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Avi Loeb: Aliens, Black Holes, and the Mystery of the Oumuamua | Lex Fridman Podcast #154


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The following is a conversation with Avi Loeb, an astrophysicist, astronomer, and cosmologist
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at Harvard. He has authored over 800 papers and written eight books, including his latest,
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called Extra Terrestrial, The First Sign of Intelligent Life Beyond Earth. It'll be released
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in a couple of weeks, so go preorder it now to show support for what I think is truly an important
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book in that it serves as a strong example of a scientist being both rigorous and open minded
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about the question of intelligent alien civilizations in our universe. Quick mention of our sponsors,
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with fasting. Choose wisely, my friends, and if you wish, click the sponsor links below to get a
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discount and to support this podcast. As a side note, let me say a bit more about why Avi's work
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is so exciting to me and I think to a lot of people. In 2017, a strange interstellar object,
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now named a Moa Moa, it's fun to say, was detected traveling through our solar system.
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Based on the evidence we have, it has strange characteristics which made it not like any
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asteroid or comet that we've seen before. Avi was one of the only world class scientists who
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fearlessly suggested that we should be open minded about whether it is naturally made or in fact
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is an artifact of an intelligent alien civilization. In fact, he suggested that the more likely
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explanation given the evidence is the latter hypothesis. We also talk about a lot of fascinating
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mysteries in our universe including black holes, dark matter, the big bang, and close the speed
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of light space travel. The theme throughout is that in scientific pursuits, the weird things,
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the anomalies, the ideas that right now are considered taboo should not be ignored if we're
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to have a chance at finding the next big breakthrough, the next big paradigm shift, and also if we are
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to inspire the world with the power and beauty of science. If you enjoy this thing, subscribe on
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YouTube, review it on Apple Podcasts, follow us on Spotify, support on Patreon, or connect with me
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on Twitter at Lex Friedman. And now, here's my conversation with Avi Loeb. In the introduction
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to your new book, Extra Terrestrial, you write, this book confronts one of the universe's most
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profound questions. Are we alone? Over time, this question has been framed in different ways. Is
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life here on earth the only life in the universe? Are humans the only sentient intelligence in the
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vastness of space and time? A better, more precise framing of this question would be this.
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Throughout the expanse of space and over the lifetime of the universe, are there now or have
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ever been other sentient civilizations that, like ours, explored the stars and left evidence
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of their efforts? So let me ask, are we alone? That's an excellent question. For me, the answer is
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sort of clear because I start from the principle of modesty. You know, if we believe that we are
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alone and special and unique, that shows organs. My daughters, when they were infants, they tended
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to think that they are special, unique. And then they went out to the street and realized that other
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kids are very much like them. And then they developed a sense of a better perspective about
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themselves. And I think the only reason that we are still thinking that we are special is because
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we haven't searched well enough to find others that might even be better than us. And you know,
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I say that because I look at the newspaper every morning and I see that we do foolish things. We
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are not necessarily the most intelligent ones. And if you think about it, if you open a recipe book,
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you see that out of the same ingredients, you can make very different cakes, depending on how
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you put them together and how you heat them up. And what is the chance that by taking the soup of
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chemicals that existed on earth and cooking it one way to get our life, that you got the best
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cake possible? I mean, we are probably not the sharpest cookie in the jar. And my question is,
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I mean, it's pretty obvious to me that we are probably not alone because half of all the sunlight
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stars we know now as astronomers, half of the sunlight stars from the Kepler satellite data
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have a planet the size of the earth, roughly at the same distance that the earth is from the sun.
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And that means that they can have liquid water on their surface and the chemistry of life as we
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know it. So if you roll the dice billions of times just within the Milky Way galaxy,
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and then you have tens of billions of galaxies like it within the observable volume of the
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universe, it would be extremely arrogant to think that we are special. I would think that we are
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sort of middle of the road, typical forms of life. And that's why nobody pays attention to us.
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You know, if you go down the street on a sidewalk and you see an ant, you don't pay attention or
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a special respect to that ant, you just continue to walk. And so I think that we are sort of average,
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not very interesting, not exciting. So nobody cares about us. We tend to think that we are
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special, but that's a sign of immaturity. And we're very early on in our development.
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Yes, that's another thing that we have our technology only for 100 years. And it's evolving
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exponentially right now on a three year timescale. So imagine what would happen in 100 years,
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in 1000 years, in a million years or in a billion years. Now the sun is actually
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relatively late in the star formation history of the universe. Most of the sunlight stars formed
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earlier. And some of them already died, you know, became white dwarfs. And so if you imagine that
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a civilization like ours existed around a typical sunlight star, by now, if they survive,
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they could be a billion years old. And then imagine a billion year technology,
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it would look like magic to us, you know, an approximation to God, we wouldn't be able to
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understand it. And so in my view, we should be humble. And by the way, we should probably just
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listen and not speak. Because there is a risk, right? If if if you are inferior, there is a risk
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if you speak too loudly. Something bad may happen to you. You mentioned we should be humble also in
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the sense with the analogy to ants, that they might be better than us. So there's a kind of scale
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that we're talking about. And in the question, you mentioned the word sentient. So sentience, or
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maybe the more basic formulation of that is consciousness. Do you think do you think that
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this thing within us humans in terms of the typical life form of consciousness is the essential
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element that permeates other if if there's other alien civilizations out there that they have something
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like consciousness as well? Or is this I guess I'm asking, can you try to untangle the word sentient?
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Yeah, so that's that's a good question. I think what is most abundant, depending on how long it
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survives. So if you look at us as an example, we are now we do have consciousness and we do have
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technology. But the technologies that we are developing are also means for our own destruction,
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as we can tell, you know, we can change the climate if we are not careful enough,
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we can go into nuclear wars. So we are developing means for our own destruction through self
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inflicted wounds. And it might well be that creatures like us are not long lived, that the
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crocodiles on other planets live for billions of years, they don't destroy themselves, they live
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naturally. And so if you look around, the most common thing would be dumb animals that live for
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long times, you know, not those that have conscious. But in terms of changing the environment, I think
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since I mean, humans develop tools, they've developed the ability to construct technologies
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that would lift us from this planet that we were born in. And that's something animals without
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the conscious consciousness cannot really do. And, and so I, you know, in terms of
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looking for things that are new, that went beyond the circumstances they were born into,
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I would think that even if they're short lived, these are the creatures that made the biggest
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difference to their environment. And we can search for them, you know, even if they're short lived,
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and most of the civilizations are dead by now. Yeah, even if that's the case,
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that's sad to think about, by the way. Well, but if you look on earth, that, you know,
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there are lots of cultures that existed throughout time, and they're dead by now,
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the Mayan culture was very sophisticated, died, but we can find evidence for it and learn about it
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just by archaeology, digging into the ground looking. And so we can do the same thing in space,
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look for dead civilizations. And perhaps we can learn a lesson why they died and behave better
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so that we will not share the same fate. So I think, you know, there is a lesson to be learned
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from the sky. And by the way, I should also say, if we find the technology that we have not
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dreamed of, that we can import to earth, that may be a better strategy for making a fortune
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than going to Silicon Valley or going to Wall Street. Because you learn, you make a jump start
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into something of the future. So that's one way to do the leap is actually to find,
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to literally discover versus come up with the idea in our own limited human capacity,
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like a cognitive capacity. It would look like it would feel like cheating in an exam where
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you look over the shoulder of a student next to you. But it's not good on an exam, but it is good
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when you're coming up with technology that could change the fabric of human civilization. But
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there is, you know, in my neck of the woods of artificial intelligence, there's a lot of
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trajectories one can imagine of creating very powerful beings, the technology that's essentially,
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you know, you can call superintelligence that could achieve space exploration,
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all those kinds of things without consciousness, without something that to us humans looks like
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consciousness. And there, you know, there is a sad feeling I have that consciousness too,
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in terms of us being humble, is a thing we humans take too seriously, that it's we think
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it's special just because we have it. But it could be a thing that's actually holding us back
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in some kind of way. It may well be. It may well be. I should say something about AI, because I do
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think it offers a very important step into the future. If you look at the Old Testament, the
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Bible, there is this story about Noach's Ark that you might know about. Yes. Noach knew about
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a great flood that is about to endanger all life on earth. So he decided to build an Ark.
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And the Bible actually talks about specifically what the size of this Ark was, what the dimensions
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were. Turns out it was quite similar to Uumuamua that we will discuss in a few minutes. But
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at any event, he built this Ark, and he put animals on it so that they were saved from the great
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flood. Now, you can think about doing the same on earth, because there are risks for future
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catastrophes. You know, we could have the self inflicted wounds that we were talking about,
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like nuclear war, changing the climate, or there could be an asteroid impacting us just like the
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dinosaurs died. The dinosaurs didn't have size, astronomy, they couldn't have a warning system,
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but there was this big stone, big rock that approached them. It must have been a beautiful
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sight just when it was approaching, got very big and then smashed them and killed them.
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So you could have a catastrophe like that, or in a billion years, the sun will basically boil
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off all the oceans on earth. And currently, all our eggs are in one basket, but we can spread them.
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It's sort of like the printing press, if you think about it, the revolution that Gutenberg
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brought is there were very few copies of the Bible at the time, and each of them was precious
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because it was handwritten. But once the printing press produced multiple copies, you know, if
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something bad happened to one of the copies, it wasn't a catastrophe, you know, it wasn't a disaster,
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because you had many more copies. And so if we have copies of life here on earth elsewhere,
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then we avoid the risk of it being eliminated by a single point breakdown, a catastrophe.
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So the question is, can we build NOx spaceship that will carry life as we know it? Now, you might
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think we have to put elephants and whales and birds on a big spaceship. But that's not true,
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because all you need to know is the DNA making, the genetic making of these animals, put it on
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a computer system that has AI plus a 3D printer, so that this cubesat, which is rather small,
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can go with this information to another planet and use the raw materials there
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to produce synthetic life. And that would be a way of producing copies, just like the Gutenberg
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printing press. Yeah, and it doesn't have to be exact copies of the humans, it could just
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contain some basic elements of life and then have enough life on board that it could
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reproduce the process of evolution on another place. Right. So that also makes you sad, of course,
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because you confront the mortality of your own little precious consciousness and all your own
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memories and knowledge and all that stuff. That's right. But who cares? I mean, we are not so...
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I care about mine, right? And you care about yours. No, no, I actually don't. You know,
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if you look at the big... If you're an astronomer, one thing that you learn from the universe is
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to be modest, because you are not so significant. Oh, boy. I mean, think about it. All these
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emperors and kings that conquered the peace of land on Earth and were extremely proud. You know,
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you see these images of kings and emperors that usually are alpha males and they stand strong and
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they're very proud of themselves. But if you think about it, there are 10 to the power 20
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planets like the Earth in the observable volume of the universe. And this view of conquering a
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piece of land that even conquering all of Earth is just like an ant hugging a single grain of sand
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on the landscape of a huge beach. That's not very impressive. So you can't be arrogant. If you see
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the big picture, you have to be humble. You know, also we are short lived. You know, within 100 years,
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that's it, right? So what does it teach you? First, to be humble, modest. You never have
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significant powers relative to the big scheme of things. And second, you should appreciate every
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day that you live and learn about the world. Humble and still grateful. Yes, exactly. Well, let's
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talk about probably the most interesting object I've heard about and also the most fun to pronounce.
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Can you tell me the story of this object and why it may be an important event in human history?
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And is it possibly a piece of alien technology? Right. So this is the first object that was
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spotted close to Earth from outside the solar system. And it was found on October 19, 2017.
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And at that time, it was receding away from us. And at first, astronomers thought it must be a
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piece of rock, you know, just like all the asteroids and comets that we have seen from within the solar
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system. And it just came from another star. I should say that the actual discovery of this
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object was surprising to me because a decade earlier, I wrote the first paper together with
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Ed Turner and Amaya Morrow Martin, that tried to predict whether the same telescope that was
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serving the sky, pan stars from Hawaii, would find anything from interstellar space, given what we
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know about the solar system. So if you assume that other planetary systems have similar
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abundance of rocks and you just calculate how many should be ejected into interstellar space,
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the conclusion is no, we shouldn't find anything with pan stars. To me, I apologize,
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probably reviewing my stupidity, but it was surprising to me that so few interstellar objects
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from outside this whole system have ever been detected or none. None has been. You do maybe
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talk about it that there has been one or two rocks since then. Well, since then, there was one
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called the Borisov. It was discovered by an amateur Russian astronomer, Gennady Borisov.
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And that one looked like a comet. And just like a comet from within the solar system.
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But this is a really important point. Sorry to interrupt that. You showed that it's unlikely
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that a rock from another solar system would arrive to ours. Right. And so the actual detection of
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this one was surprising by itself, to me. Yes. But then, so at first they thought maybe it's a
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comet or an asteroid, but then it looked, it didn't look like anything we've seen before.
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Borisov did look like a comet. So people asked me afterwards and said, you know,
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doesn't it convince you that if Borisov looks like a comet, doesn't it convince you that
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Oumuamua is also natural? Yeah. And I said, you know, when I went on the first date with my wife,
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she looked special to me. Yes. And since then I met many women. Yes. That didn't change my
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opinion of my wife. You know, that's not an argument. Anyway, so why did Oumuamua look
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weird? Let me explain. So first of all, astronomers monitored the amount of light,
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sunlight that it reflects. And it was tumbling, spinning every eight hours. And as it was spinning,
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the brightness that we saw from that direction, we couldn't resolve it because it's tiny. It's
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about 100 meters, a few hundred feet, size of a football field. And we cannot, from Earth,
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we with existing telescopes, we cannot resolve it. The only way to actually get a photograph of it
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is to send the camera close to it. And that was not possible at the time that Oumuamua was
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discovered because it was already moving away from us faster than any rocket we can send.
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It's sort of like a guest that appeared for dinner. And then by the time we realized that
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it's weird, the guest is already out the front door into the dark street. What we would like
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to find is an object like it approaching us because then you can send the camera irrespective
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of how fast it moves. And if we were to find it in July 2017, that would have been possible
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because it was approaching us at that time. Actually, I was visiting Mount Haleakala
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in Maui, Hawaii with my family for vacation at that time in July 2017. But nobody knew
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at the observatory that the Oumuamua is very close. That's sad to think about that. We had
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the opportunity at that time to send up a camera. But don't worry. I mean, there will be more.
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There will be more because I operate by the Copernican principle, which says we don't leave
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at a special place and we don't leave at a special time. And that means if we surveyed the sky for
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a few years and we had sensitivity to this region between us and the sun, and we found this object
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with panstas, there should be many more that we will find in the future with surveys that
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might be even better. And actually, in three years time scale, there would be the so called LST.
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That's a survey of the Vera Rubin Observatory that would be much more sensitive and could
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potentially find an Oumuamua like object every month. Okay, so I'm just waiting for that. And
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the main reason for me to alert everyone to the unusual properties of Oumuamua is with the hope
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that next time around when we see something as unusual, we would take a photograph or we would
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get as much evidence as possible because science is based on evidence, not on prejudice. And we
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will get back to that theme. So anyway, let me let me point out some of the properties actually,
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yeah, the elongated nature, all those other things. So the light, the amount of light sunlight that
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was reflected from it was changing over eight hours by a factor of 10, meaning that the area
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of this object, even though we can't resolve it, the area on the sky that reflects sunlight
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was bigger by a factor of 10 in some phases as it was tumbling around than in other phases. So
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even if you take a piece of paper that is razor thin, you know, it's there is a very small likelihood
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that it's exactly a John. And getting a factor of 10 change in the area that you see on the sky
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is huge. It's much more than any. It means that the object has an unusual geometry. It's at least
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a factor of a few more than any of the comets or asteroids that we have seen before.
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You mentioned reflectivity. So it's not just the geometry, but the properties of the surface of that
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thing. Well, or no, if you assume the reflectivity is the same, then it's just geometry. If you
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assume the reflectivity may change, then it could be a combination of the area that you see and
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the reflectivity, because different directions may reflect differently. But the point is that
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it's very extreme. Yes. And it actually the best fit to the light curve that we saw was of a flat
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object. Unlike all the cartoons that you have seen of a cigar shape, a flat object at the 90%
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confidence gives a better model for the way that the light varied. And it's like flat meaning like
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a pancake like a pancake. Exactly. And so that's, you know, the very first unusual property. But
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to me, it was not unusual enough to think that it might be artificial. It was not
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significant enough. Then there was no cometary tail, you know, no dust, no gas around this
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object. And the Spitzer Space Telescope really searched very deeply for carbon based molecules.
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There was nothing. So it's definitely not a comet the way people expected it to be.
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00:23:49.840
Can you maybe briefly mention what property is a comet that you're referring to usually has?
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00:23:55.840
Right. So a comet is a rock that has some water ice on the surface. So you can think of it as an
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00:24:02.960
icy rock. Actually, comets were discovered a long time ago. But the first model that was developed
link |
00:24:12.400
for them was by Fred the Whipple, who was at Harvard. And I think the legend goes that he got the
link |
00:24:19.920
idea from walking through Harvard Square and seeing during a winter day and seeing these icy rocks,
link |
00:24:27.040
you know, and so a comet is icy. It's just a rock. It's just a rock. So when you have ice on the
link |
00:24:34.960
surface, when the rock gets close to the sun, the sunlight warms it up. And the ice sublimates,
link |
00:24:43.520
evaporates. Because the one thing about ice, water ice, is it doesn't become liquid if you warm it up
link |
00:24:51.040
in vacuum, you know, without an external pressure. It just goes straight into gas. And that's what
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00:24:58.000
you see as the tail of a comet. The only way to get liquid water is to have an atmosphere like on
link |
00:25:05.280
Earth that has an external pressure. Only then you get liquid. And that's why it's essential to have
link |
00:25:11.680
an atmosphere to a planet in order to have liquid water and the chemistry of life. So if you look
link |
00:25:17.120
at Mars, Mars lost its atmosphere. And therefore, no liquid water on the surface anymore. I mean,
link |
00:25:23.760
there may have been early and that's what the Perseverance survey, you know, the Perseverance
link |
00:25:30.000
mission will try to find out whether it had liquid water, whether there was life, perhaps,
link |
00:25:35.200
on it at the time. But at some point, it lost its atmosphere. And then the liquid water was gone.
link |
00:25:41.200
So the only reason that we can live on Earth is because of the atmosphere. But a comet is in
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00:25:47.760
vacuum, pretty much. And when it gets warmed up on the surface, the water becomes the water ice
link |
00:25:55.920
becomes gas. And then you see this cometary tail behind it. In addition to water, there is that
link |
00:26:03.120
there are all kinds of carbon based molecules or dust that comes off the surface. And those are
link |
00:26:08.240
detectable. Yeah, it's easy to detect. It's very prominent. You see these cometary tails that look
link |
00:26:14.000
very prominent because they reflect sunlight. And you can see them. In fact, it's sometimes
link |
00:26:18.160
difficult to see the nucleus of the comet, because it's surrounded and shrouded with. And in this
link |
00:26:24.000
case, there was no trace of anything. That's fascinating. Now, you might say, okay, it's not
link |
00:26:28.800
a, so that's what the community said. Okay, it's not a no problem. It's still a rock, you know,
link |
00:26:32.960
it's not a comet, but it's just a rock, bare rock, you know, okay, no problem. Then, and that's the
link |
00:26:40.000
thing that convinced me to write about it. And then in June 2018, you know, significantly later,
link |
00:26:46.880
there was a report that in fact, the object exhibited an excess push in addition to the
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00:26:55.200
force of gravity. So the sun acts on it by gravity, but then there was an extra push on
link |
00:27:00.240
this object that was figured out from the orbit that you can trace. And the question was, what is
link |
00:27:06.720
this excess push? So for comets, you get the rocket effect. When you evaporate gas, you know,
link |
00:27:12.320
just like a jet engine on an airplane, you throw a jet engine is very simple, you throw the gas back,
link |
00:27:19.280
and it pushes the airplane forward. That's all. That's how a jet. So in a case of a comet, you
link |
00:27:24.400
throw gas in the direction of the sun because it's, and then you get a push. Okay. So in the
link |
00:27:30.400
case of comets, you can get a push, but there was no cometary tail. So then people say, oh, wait a
link |
00:27:36.000
second. Is it an asteroid? No, but it behaves like a comet, but it doesn't look like a comet.
link |
00:27:41.200
So what, well, forget about it, business as usual. So that's what they mean by a non
link |
00:27:46.240
gravitation, non gravitational acceleration. So that's interesting. So like the primary force
link |
00:27:51.760
acting on something like just a rock like an asteroid would be like you can predict a trajectory
link |
00:27:57.360
based on the gravity, based on gravity. And also here there's detected movement that's not,
link |
00:28:02.880
cannot be accounted purely by the gravity of the sun. And if it was a comet, you would need
link |
00:28:07.120
about a tenth of the mass of this comet, the weight of this comet to be evaporated in order
link |
00:28:13.600
to give it. And there was no sign of that. No sign. 10% of the mass evaporating. It's huge.
link |
00:28:19.200
Think about it, a 100 meter size object losing 10% of its mass. You can't miss that.
link |
00:28:25.440
And so that's super weird. It's super weird. What is there a good expo? Is there in your mind
link |
00:28:30.880
a possible explanation for that? You know, so I operated just like Sherlock Holmes in a way.
link |
00:28:35.280
I said, okay, what are the possibilities? And the only thing I could think, so I ruled out
link |
00:28:39.760
everything else. And I said, it must be the sunlight reflected off it. Okay. So the sunlight
link |
00:28:46.720
reflects off the surface and gives it a push, just like you get a push on a sail on a boat,
link |
00:28:53.440
you know, from the wind reflecting off it. Now, in order for this to be effective,
link |
00:28:59.040
it turns out the object needs to be extremely thin. It turns out it needs to be less than a
link |
00:29:04.880
millimeter thick. Nature does not produce such things. So but we produce it because it's called
link |
00:29:13.120
the technology of a light sail. So we are for space exploration, we are exploring this technology
link |
00:29:19.040
because it has the benefit of not needing to carry the fuel with the spacecraft. So you don't have
link |
00:29:25.040
the fuel, you just have a you just have a sail and it's being pushed either by sunlight or by a
link |
00:29:32.880
laser beam or whatever. So perhaps this is a light sail. So this is actually the same technology
link |
00:29:40.320
with the with the Starshot project? Yes. So you know, people afterwards say, okay, you work on
link |
00:29:46.640
this project, you imagine, you know, no, that's a pretty good explanation, right? Obviously,
link |
00:29:50.960
my imagination is limited by what I know. So I, you know, I would not deny that,
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00:29:56.560
you know, working on light sails expanded my ability to imagine this possibility.
link |
00:30:01.840
But let me offer another interesting anecdote. In September this year, 2020, I mean,
link |
00:30:08.560
2020, there was another object found. And it was given the name 2020 SO by the
link |
00:30:17.600
Minor Planet Center. You know, this is an organization actually in Cambridge, Massachusetts,
link |
00:30:24.320
that gives names to objects, astronomical objects found in the solar system. And they gave it that
link |
00:30:30.080
name 2020 SO because you know, it looked like an object in the solar system. And it moved in an orbit
link |
00:30:37.840
that is similar to the orbit of the earth, but not the same exactly. And therefore, it was bound
link |
00:30:44.320
to the sun, but it also exhibited a deviation from what you expect based on gravity. So they
link |
00:30:51.680
astronomers that found it extrapolated back in time and found that in 1966, it intercepted the earth.
link |
00:31:00.640
And then they realized they went to the history books and they realized, oh, there was a mission
link |
00:31:04.960
called lunar surveyor, lunar lander, surveyor two that had a rocket booster. It was a failed mission,
link |
00:31:12.880
but there was a rocket booster that was kicked into space. And presumably, this is the rocket
link |
00:31:18.800
booster that we are seeing. Now, this rocket booster was sufficiently hollow and thin for us to
link |
00:31:24.800
recognize that it's pushed by sunlight. So here is my point. We can tell from the orbit of an
link |
00:31:31.200
object. Obviously, this object didn't have any cometary tail. It was artificially made. We know
link |
00:31:37.280
that it was made by us and it did deviate from an orbit of a rock. So just by seeing something
link |
00:31:45.600
that doesn't have cometary tail and deviates from an orbit shaped by gravity, we can tell that it's
link |
00:31:51.520
artificial. In the case of a Muammua, it couldn't have been sent by humans because it just passed
link |
00:31:57.840
near us for a few months. We know exactly what we were doing at that time. And also it was moving
link |
00:32:03.440
faster than any object that we can launch. And so obviously it came from outside the solar system.
link |
00:32:09.600
And the question is who produced it? Now, I should say that when I walk on vacation on a beach,
link |
00:32:16.320
I often see natural objects like seashells that are beautiful and I look at them. And every now
link |
00:32:24.000
and then I stumble on a plastic bottle that was artificially produced. And my point is that maybe
link |
00:32:32.000
a Muammua was a message in a bottle. And this is simply another window into searching for artifacts
link |
00:32:40.240
from other civilizations. Where do you think it could have come from? And from a scientific
link |
00:32:50.400
perspective, the narrow minded view, as we'll probably talk about throughout, is you kind of
link |
00:32:58.400
want to stick to the things that to naturally originating objects like asteroids and comets.
link |
00:33:05.280
Okay, that's the space of possible hypotheses. And then if we expand beyond that,
link |
00:33:10.000
you start to think, okay, these are artificially constructed. Like you just said, it could be by
link |
00:33:14.000
humans. It could be by by whatever that means by some kind of extraterrestrial alien civilizations.
link |
00:33:22.880
If it's the alien civilization variety, what is this object then? That's an excellent question.
link |
00:33:31.920
An excellent question. And let me lay out, I mean, we don't have enough evidence to tell. If we had a
link |
00:33:37.200
photograph, perhaps we would have more information. But there is one other peculiar fact about
link |
00:33:43.440
a Muammua. Well, other than it was very shiny, that I didn't mention, you know, we didn't detect
link |
00:33:50.800
any heat from it. And that implies that it's rather small and shiny. But the other peculiar fact is
link |
00:33:58.160
that it was it came from a very special frame of reference. So it's sort of like finding a car
link |
00:34:04.400
in a parking lot in a public parking lot that, you know, you can't really tell where it came from.
link |
00:34:11.440
So there is this frame of reference where you average over the motions of all the stars in
link |
00:34:16.640
the neighborhood of the sun. So you find the so called local standard of rest of the galaxy.
link |
00:34:24.560
And that's a frame of reference that is obtained by averaging the random motions of all the stars.
link |
00:34:31.520
And the sun is moving relative to that frame at some speed. But this object was at rest in that
link |
00:34:37.760
frame. And only one in 500 stars is so much at rest in that frame. And that's why I was saying
link |
00:34:44.000
it's like a parking lot. It was parked there and we bumped into it. So the relative speed between
link |
00:34:49.680
the solar system and this object is just because we are moving. It was sitting still. Now you ask
link |
00:34:57.040
yourself, why is it so unusual in that context? You know why? Because if it was expelled from
link |
00:35:03.440
another planetary system, most likely it will carry the speed of the host star that it came from.
link |
00:35:10.400
Because it was, you know, the most loosely bound objects are in the periphery of the planetary
link |
00:35:16.080
system. And they move very slowly relative to the star. And so they carry the when they are ripped
link |
00:35:22.480
apart from the planetary system, most of the objects will have the residual motion of the star,
link |
00:35:28.160
roughly relative to the local star. But this one was at rest in the local. Now,
link |
00:35:31.920
one thing I can think of if there is a grid of road posts, you know, like for navigation system,
link |
00:35:40.400
so that you can find your way in the local frame, then that would be one possibility.
link |
00:35:45.360
These are like little sensors. That's fascinating to think about. So there could be, I mean,
link |
00:35:50.000
not necessarily literally a grid, but just evenly in some definition of evenly spread out
link |
00:35:56.640
set of objects like these that are just out there. A lot of them. Another possibility is that these
link |
00:36:02.720
are relay stations, you know, for communication, you might think in order to communicate, you need
link |
00:36:07.520
a huge beacon, a very powerful beacon. But it's not true because even on Earth, you know, we have
link |
00:36:13.920
these relay stations. So you have a not so powerful beacon. So it can be heard only out to a limited
link |
00:36:20.160
distance. But then you relay the message. And it could be one of those. Now, after it collided
link |
00:36:26.160
with the solar system, of course, it got a kick. So it's just like a billiard ball, you know, we
link |
00:36:31.360
gave it a kick by colliding with, but most of them are not colliding with stars. And so that's one
link |
00:36:36.720
possibility. Okay. And there should be numerous lots of them if that's the case. The other possibility
link |
00:36:44.800
is that it's a probe, you know, that was sent in the direction of the habitable region around the
link |
00:36:54.080
sun to find out if there is life. Now, it takes tens of thousands of years for such a probe to
link |
00:36:59.520
traverse the solar system from the outer edge of the Earth cloud all the way to where we are.
link |
00:37:05.520
And, you know, it's a long journey. So when it started the journey from the edge of the solar
link |
00:37:09.200
system to get to us now, you know, we were rather primitive back then, you know, we still didn't
link |
00:37:14.800
have any technology. There was no reason to visit, you know, there was grass around and so forth.
link |
00:37:19.520
But, you know, maybe it is a probe. So you said 10,000 years as fast as so it takes that long
link |
00:37:25.520
tens of thousands. Yes, tens of thousands a year. Yeah. Yeah. And the other thing I should say is,
link |
00:37:31.360
you know, it could be just an outer layer of something else, like, you know, something that
link |
00:37:38.160
was ripped apart, like a surface of an instrument that was, and you can have lots of these pieces,
link |
00:37:45.120
you know, if something breaks, lots of these pieces spread out like space junk. And, you know,
link |
00:37:51.040
it could be just space junk from an alien civilization. Yes. So it's, I can tell you
link |
00:37:59.680
about space junk. Let me, what do you mean by space junk? So I think, you know, you might ask,
link |
00:38:07.120
why aren't they looking for us? One possibility is that we are not interesting, like we were talking
link |
00:38:11.600
about another possibility, you know, if there are millions of billions of years
link |
00:38:19.440
into their technological development, they created their own, their own habitat, their own cocoon,
link |
00:38:26.800
where they feel comfortable, they have everything they need. And it's risky for them to establish
link |
00:38:32.400
communication with other. So they have their own cocoon and they close off. They don't care about
link |
00:38:38.960
anything else. Now, in that case, you might say, oh, so how can we find about them if they are closed
link |
00:38:44.480
off? The answer is they still have to deposit trash, right? That's, that is something from the
link |
00:38:51.040
law of thermodynamics. There must be some production of trash. And, you know, we can still find about
link |
00:38:57.040
them just like investigative journalists going through the trash cans of celebrities in Hollywood,
link |
00:39:03.920
you know, you can learn about the private lives of those celebrities by looking at the trash.
link |
00:39:09.120
It's fascinating to think, you know, if, if we are the ants in this picture, if we, if this thing is
link |
00:39:14.720
a water bottle, or if it's like a smartphone, like where, where on the spectrum of possible
link |
00:39:22.080
objects of space, because there's a lot of interesting trash. So like, how interesting is
link |
00:39:28.000
this trash? But imagine a caveman seeing a cell phone. The caveman would think, since the caveman
link |
00:39:34.480
played with rocks all of his life, he would say, it's a rock, just like my fellow astronomers said.
link |
00:39:39.680
Yes. Right. Exactly. That's brilliantly put. Actually, as a scientist, do you hope it's a water
link |
00:39:45.040
bottle or a smartphone? Because I hope it's even more than a smartphone. I hope that it's something
link |
00:39:50.800
that is really sophisticated and funny. See, I'm the opposite. I feel like I hope it's a water bottle,
link |
00:39:56.640
because at least we have a hope with our current set of skills to understand it. Yeah, but caveman
link |
00:40:02.560
has no way of understanding the smartphone. It's like, it will be like, I feel like a caveman has
link |
00:40:07.680
more to learn from the plastic water bottle than it do from the smartphone. But suppose we figure
link |
00:40:12.400
it out, if we, if we, for example, come close to it and, and, and learn what it's made of.
link |
00:40:17.840
And I guess the smartphone is full of like thousands of different technologies that we could
link |
00:40:22.640
probably pick at. Do you have a sense of where a hypothesis of where is the cocoon that it might
link |
00:40:32.960
have come from? No, because there, okay. So first of all, you know, the solar system, the outermost
link |
00:40:40.880
edge of the solar system is called the Oort cloud. It's a cloud of icy rocks of different sizes
link |
00:40:50.240
that were left over from the formation of the solar system. And it's thought to be roughly
link |
00:40:57.680
a ball or a sphere. And it's halfway, the extent of it is roughly halfway to the nearest star.
link |
00:41:04.720
Okay. So you can imagine each planetary system basically touching the Oort clouds of those stars
link |
00:41:15.040
that are near us are touching each other. Space is full of these billiard balls that are very densely
link |
00:41:23.360
packed. And what that means is any object that you see irrespective of whether it came from the
link |
00:41:29.440
local standard. So we said that this object is special because it came from a local standard
link |
00:41:33.600
of rest. But even if it didn't, you would never be able to trace where it came from because
link |
00:41:38.400
all these Oort clouds overlap. So if you take some direction in the sky, you will cross
link |
00:41:46.320
as many stars as you have in that direction. Like there is no way to tell which Oort cloud it came
link |
00:41:52.000
from. So yes, I didn't realize how densely packed everything was from the perspective of the Oort
link |
00:41:57.120
cloud. And that's really interesting. So yeah, it could be nearby, it could be very far away.
link |
00:42:01.920
Yeah, we have no clue. You said cocoon. And you kind of paint, I think in the book, I've
link |
00:42:11.760
read a lot of your articles too on the Scientific American, which are brilliant. So I'm kind of
link |
00:42:15.600
mixing things up in my head a little bit. But there's what does that cocoon look like? What
link |
00:42:22.080
is the civilization that's able to harness the power of multiple suns, for example,
link |
00:42:26.560
look like? When you imagine possible civilizations that are a million years more advanced than us,
link |
00:42:34.000
what do you think that actually looks like? I think it's very different than we can imagine.
link |
00:42:40.160
By the way, I should start from the point that even biological life, just without technology
link |
00:42:46.960
getting into the game, could look like something we have never seen before. Take, for example,
link |
00:42:53.120
the nearest star, which is Proxima Centauri. It's four and a quarter light years away. So they will
link |
00:42:59.200
know about the results of the 2016 elections only next month in February 2021. It's very far away.
link |
00:43:09.360
But if you think about it, you know, this star is a dwarf star. And it's much cooler than it's
link |
00:43:19.680
twice as cold as the sun. And it emits mostly infrared radiation. So if there are any creatures
link |
00:43:27.680
on the planet close to it that is habitable, which is called Proxima B, there is a planet
link |
00:43:34.960
in the habitable zone, in the zone just at the right distance where in principle liquid water
link |
00:43:39.520
can be on the surface. If there are any animals there, they have infrared eyes because our eyes
link |
00:43:45.760
was designed to be sensitive to where most of the sunlight is in the visible range. But
link |
00:43:52.800
Proxima Centauri emits mostly infrared. So you know, the nearest to see each other in the nearest star
link |
00:43:58.800
system, these animals would be quite strange. They would have eyes that are detectors of
link |
00:44:05.040
infrared very different from ours. Moreover, this planet Proxima B faces the star always with the
link |
00:44:11.200
same side. So it has a permanent day side and a permanent night side. And obviously the creatures
link |
00:44:17.600
that would evolve on the permanent day side, which is much warmer, would be quite different than
link |
00:44:22.480
those on the permanent night side. Between them, there would be a permanent sunset strip. And my
link |
00:44:29.280
daughters said that that's the best opportunity for high value real estate because you will see the
link |
00:44:35.040
sunset throughout your life, right? The sun never sets on this strip. So you know, these worlds are
link |
00:44:44.160
out of our imagination. Just even the individual creatures, the sensor suite that they're operating
link |
00:44:50.000
with might be very different. Very different. So I think when we see something like that,
link |
00:44:53.680
we would be shocked not to speak about seeing technology now. So I don't even dare to imagine,
link |
00:44:59.920
you know? And I think, you know, obviously we can bury our head in the sand and say,
link |
00:45:06.560
it's never aliens, like many of my colleagues say. And it's a self fulfilling prophecy. If you
link |
00:45:12.560
never look, you will never find. If you are not ready to find wonderful things, you will never
link |
00:45:18.160
discover them. And the other thing I would like to say is reality doesn't care whether you ignore
link |
00:45:24.640
it or not. You can ignore reality, but it's still there. So we can all agree based on Twitter
link |
00:45:32.560
that aliens don't exist. That was a rock. We can all agree. And you will get a lot of likes.
link |
00:45:40.240
Have a big crowd of supporters and everyone will be happy and give each other awards and
link |
00:45:45.040
honours and so forth. But might still be an alien artifact. Who cares what humans agree on.
link |
00:45:53.840
There is a reality out there. And we have to be modest enough to recognize that we should make
link |
00:46:00.880
our statements based on evidence. Science is not about ourselves. It's not about glorifying our
link |
00:46:08.000
image. It's not about getting honours, prizes, you know, a lot of the scientific, a lot of the
link |
00:46:13.600
academic activity is geared towards creating your echo chamber where you have students,
link |
00:46:19.200
postdocs repeating your mantras so that your voice is heard loudly so that you can get more
link |
00:46:24.640
honours, prizes, recognition. That's not the purpose of science. The purpose is to figure out
link |
00:46:30.960
what nature is, right? And in the process of doing that, it's a learning experience. You make mistakes.
link |
00:46:36.960
You know, Einstein made three mistakes at the end of his career. He argued that in the 1930s,
link |
00:46:43.120
he argued that black holes don't exist, gravitational waves don't exist, and quantum
link |
00:46:49.360
mechanics doesn't have spooky action at a distance. And all three turned out to be wrong.
link |
00:46:56.000
Okay. So the point is that if you work at the frontier, then you make mistakes. It's inevitable
link |
00:47:01.600
because you can tell what is true or not. And avoiding making mistakes in order to preserve
link |
00:47:06.800
your image makes you extremely boring. Okay. You will get a prize, but you will be a boring
link |
00:47:13.520
scientist because you will keep repeating things we already know. If you want to make progress,
link |
00:47:18.480
if you want to innovate, you have to take risks and you have to look at the evidence.
link |
00:47:23.840
It's a dialogue with nature. You don't know the truth in advance. You let nature tell you, educate
link |
00:47:30.240
you. And then you realize that what you thought before is incorrect. And a lot of my colleagues
link |
00:47:38.240
prefer to be in a state where they have a monologue. You know, if you look at these people that work
link |
00:47:42.240
on string theory, they have a monologue. They know what, and in fact, their monologue is centered on
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00:47:48.960
anti the sitter space, which we don't live in. Now, you know, it's to me, it's just like the
link |
00:47:54.400
Olympics, you know, you define a hundred meters, and you say whoever runs this hundred meters is the
link |
00:48:00.160
best athlete, the fastest, you know, and it's completely arbitrary. You could have decided
link |
00:48:05.280
it would be 50 meters or 20 meters. Who cares? You just measure the ability of people this way.
link |
00:48:11.200
So you define anti the sitter space as a space where you do your mathematical gymnastics,
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00:48:16.480
and then you find who can do it the best, and you give jobs based on that, you give prizes.
link |
00:48:20.480
But as we said before, you know, nature doesn't care about, you know, the prizes that you give
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00:48:27.120
to each other. It cares, you know, it has its own reality, and we should figure it out. And
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00:48:33.200
it's not about us. The scientific activity is about figuring out nature. And sometimes we may be
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00:48:38.880
wrong. Our image will not be preserved. But it's that's the fun, you know, kids explore the world
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00:48:47.920
out of curiosity. And I always want to maintain my childhood curiosity. And I don't care about
link |
00:48:53.520
the labels that I have. In fact, having tenure is exactly the opportunity to behave like a child,
link |
00:49:00.480
because you can make mistakes. And I was asked by the Harvard Gazette, you know, the Pravda
link |
00:49:07.200
of Harvard, what is the one thing that you would like to change about the world?
link |
00:49:14.000
Yes. And I said, I would like my colleagues to behave more like kids. Yeah, that's the one thing
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00:49:20.640
I would like them to do. Because something bad happens to these kids when they become
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00:49:26.400
tenured professors, they start to worry about their ego, and about themselves more than about
link |
00:49:32.400
the purpose of science, which is, you know, curiosity driven, figuring out from evidence.
link |
00:49:37.120
Evidence is the key. So when an object shows anomalies, like, what's the problem discussing,
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00:49:43.360
you know, whether it's artificial or not, you know, so there was, I should tell you,
link |
00:49:47.360
there was a mainstream paper in nature, published saying, it must be natural. That's it.
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00:49:54.880
It's unusual, but it must be natural. Period. And then at the same time,
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00:50:00.400
that those means some other mainstream scientists tried to explain the properties.
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00:50:05.680
Yes. And they came up with interpretations like, it's a dust bunny, you know, the kind
link |
00:50:10.560
that you find in a household, a collection of dust particles pushed by sunlight,
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00:50:16.240
something we have never seen before. Or it's a hydrogen iceberg. It actually evaporates like a
link |
00:50:21.920
comet, but hydrogen is transparent. You don't see it. And that's why we don't see the cometary
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00:50:26.560
tail. Again, we have never seen something like that. In both cases, the objects would not
link |
00:50:31.760
survive the long journey. We discussed it in a paper that I wrote afterwards. But my point is,
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00:50:37.920
those that tried to explain the unusual properties went into great length at discussing things that
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00:50:44.800
we have never seen before. Okay. So even when you think about the natural origin, you have to come
link |
00:50:50.400
up with scenarios of things that were never seen before. And by the way, they look less plausible
link |
00:50:57.120
to me personally. But my point is, if we discuss things that were never seen before, right,
link |
00:51:02.960
why not discuss, why not contemplate an artificial origin? What's the problem? Why do people have
link |
00:51:09.760
this pushback? You know, I worked on dark matter. And we don't know what most of the matter in the
link |
00:51:17.200
universe is. It's called dark matter. It's just an acronym, because we have no clue. We simply
link |
00:51:23.280
don't know. So it could be all kinds of particles. And over the years, people suggested weekly
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00:51:27.680
interacting massive particles, axions, all kinds of particles. And experiments were made. They
link |
00:51:33.760
cost hundreds of millions of dollars. They put upper limits, constraints that ruled out many
link |
00:51:40.080
of the possibilities that were proposed as natural initially. The mainstream community regarded it
link |
00:51:45.840
as a mainstream activity to search the nature of the dark matter. And they nobody complained that
link |
00:51:52.080
it's speculative to consider weekly interacting massive particles. Now, I ask you, why is it
link |
00:51:58.160
speculative to consider extraterrestrial technologies? We have a proof that it exists here
link |
00:52:05.280
on Earth. We also know that the conditions of Earth are reproduced in billions of systems
link |
00:52:12.960
throughout the Milky Way galaxy. So what's more conservative than to say, if you arrange for
link |
00:52:18.160
similar conditions, you get the same outcome. How can you imagine this to be speculative? It's not
link |
00:52:23.600
speculative at all. And nevertheless, it's regarded the periphery. And at the same time, you have
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00:52:28.640
physicists, theoretical physicists working on extra dimensions, supersymmetry, super string theory,
link |
00:52:35.920
the multiverse, maybe we live in a simulation, all of these ideas that have no grounding in reality,
link |
00:52:42.480
some of which sound to me like, you know, just like what someone would say, science fiction,
link |
00:52:49.600
basically, because you have no way to test it, you know, through experiments and experiments really
link |
00:52:56.720
are key. It's not just the nuance. You say, okay, I forget about experiments, as some philosophers
link |
00:53:01.440
try to say, you know, if there is a consensus, what's the problem? The point is, it's key,
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00:53:06.560
then that's what Galileo, it's key to have feedback from reality. You know, you can think that you
link |
00:53:11.680
have a billion dollars or that you are more rich than, you know, Elon Musk, that's fine. You can
link |
00:53:19.040
feel very happy about it. You can talk about it with your friends and all of you will be happy
link |
00:53:23.600
and think about what you can do with the money. Then you go to an ATM machine and you make an
link |
00:53:27.920
experiment, you check how much money you have in your checking account. And if it turns out that,
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00:53:34.080
you know, you don't have much, you can't materialize your dreams. Okay, so you realize you have a
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00:53:40.800
reality check. And my point is, without experiments giving you a reality check, without the ATM
link |
00:53:46.080
machine showing you whether your ideas are bankrupt or not, without putting skin in the game. And by
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00:53:52.400
skin in the game, I mean, don't just talk about theoretical ideas, make them testable. If you
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00:53:58.720
don't make them testable, they're worthless. They're just like theology that is not testable.
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00:54:04.160
By the way, theology has some tests. Let me give you three examples. Yes.
link |
00:54:12.480
It turns out that my book already inspired a PhD student at Harvard in the English department
link |
00:54:19.040
to pursue a PhD in that direction. And she invited me to the PhD exam a couple of months ago.
link |
00:54:26.240
And in the exam, one of the examiners, a professor asked her, do you know why Giordano Bruno was
link |
00:54:36.080
burnt at the stake? And she said, I think it's because he was an obnoxious guy and
link |
00:54:42.800
they irritated a lot of people, which is true. But the professor said, no, it's because Giordano
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00:54:51.520
Bruno said that other stars are just like the sun and they could have a planet like the earth
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00:54:58.960
around them that could host life. And that was offensive to the church. Why was it offensive?
link |
00:55:07.200
Because there is the possibility that this life sinned. Okay. And if that life sinned
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00:55:14.400
on planets around other stars, it should have been saved by Christ. And then you need multiple
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00:55:20.560
copies of Christ. And that's unacceptable. How can you have duplicates of Christ? And so they burned
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00:55:28.000
the guy. It was about, okay, I'm just like loading this all in, because that's kind of brilliant.
link |
00:55:35.600
So he was actually already into this, it's not just about the stars, it's anticipating that there
link |
00:55:39.600
could be other life forms. Like why if this star, if there's other stars, why would it be special?
link |
00:55:46.080
Why would our star be special? He was making the right arguments. And he would just follow that
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00:55:51.040
all along to say like there should be other earth like places, there should be other life forms.
link |
00:55:56.240
And then that was offense copies of Christ. Yes. So that was offensive. So I said, I said to that,
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00:56:03.040
I said to that professor, I said, great, you know, I wanted to introduce some scientific tone to the
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00:56:07.840
discussion. And I said, this is great, because now you basically laid the foundation for an
link |
00:56:13.680
experimental test of this theology. What is the test? We now know that other stars are like the sun.
link |
00:56:20.720
And we know they have planets like the earth around them. So suppose we find life there,
link |
00:56:25.520
and we figure out that they sinned, then we ask them, did you witness Christ? And if they say no,
link |
00:56:34.000
it means that this theology is ruled out. So there is an experimental test. So this is
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00:56:39.680
experimental test number one. Another experimental test, you know, in the Bible, you know, in the
link |
00:56:47.120
Old Testament, Abraham was heard the voice, the voice of God to sacrifice his son, right? Only son.
link |
00:56:59.040
And that's what the story says. Now suppose Abraham, my name, by the way, had a voice memo up on his
link |
00:57:08.720
cell phone. He could have pressed this up and recorded the voice of God. And that would have
link |
00:57:14.400
been experimental evidence that God exists, right? Fortunately, he didn't. But it's an experimental
link |
00:57:21.520
test, right? There is a third example I should tell. And that is Elie Wiesel attributed this story
link |
00:57:28.800
to Martin Buber. But it's not clear whether it's true or not. At any event, the story goes that
link |
00:57:34.160
Martin Buber, you know, he was a philosopher and he said, you know, the Christians argue that Jesus,
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00:57:41.920
you know, the Messiah arrived already and will come back again in the future. The Jews argue
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00:57:50.240
the Messiah never came and will arrive in the future. So he said, why argue? Both sides agree
link |
00:57:58.320
that the Messiah will arrive in the future. When the Messiah arrives, we can ask whether he or she
link |
00:58:07.600
came before, you know, like visited us and then figure it out. And one side, so again,
link |
00:58:12.880
experimental test of a theology. So even theology, if it puts a skin in the game, you know, if it
link |
00:58:20.080
makes a prediction, could be tested, right? So why can't string theories test themselves? Or why can't,
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00:58:26.560
you know, even cosmic inflation, that's another model that, you know, one of the inventors from
link |
00:58:31.120
MIT, Alan Guth argues that it's not falsifiable. My point is, a theory that cannot be falsified
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00:58:39.360
is not helpful, because it means that you can't make progress. You cannot improve your understanding
link |
00:58:44.720
of nature. The only way for us to learn about nature is by making hypotheses that are testable,
link |
00:58:51.280
doing the experiments and learning whether we are correct or not. So be and coupled that with
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00:58:57.280
a curiosity and open mindedness that allows us to explore all kinds of possible hypotheses,
link |
00:59:03.120
but always the pursuit of those, the scientific rigor around those hypotheses is ultimately
link |
00:59:11.360
get evidence. Knowledge is, of what nature is, should be a dialogue with nature. Yes.
link |
00:59:18.320
Rather than a monologue. Monologue, beautifully put. Can we talk a little bit about the Drake
link |
00:59:23.040
equation, another framework from which to have this kind of discussion about possible civilizations
link |
00:59:29.200
out there? So let me ask, within the context of the Drake equation, or maybe bigger, how many
link |
00:59:35.440
alien civilizations do you think are out there? Well, it's hard to tell, because the Drake equation
link |
00:59:40.240
is again quantifying our ignorance. It's just a set of factors. The only one that we know,
link |
00:59:47.280
or actually two that we know quite well is the rate of star formation in the Milky Way Galaxy,
link |
00:59:52.960
which we measured by now, and the frequency of planets like the Earth around stars,
link |
01:00:00.080
and at the right distance to have life. But other than that, there are lots of implicit
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01:00:06.560
assumptions about all the other factors that will enable us to detect a signal.
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01:00:10.160
Now, I should say that Drake equation has a very limited validity just for signals from civilizations
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01:00:17.520
that are transmitting at the time that you're observing them. However, we can do much better
link |
01:00:24.160
than that. We can look for artifacts that they left behind. Even if they're dead, you can look for
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01:00:31.600
industrial pollution in the atmosphere of planets. Why do I bring this up? Again, to show you the
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01:00:37.920
conservatism of the mainstream in astronomy. By the way, I have leadership positions. I was
link |
01:00:43.760
chair of the Astronomy Department for nine years, the longest serving chair at Harvard.
link |
01:00:48.080
I'm the chair of the Board on Physics and Astronomy of the National Academies. It's a
link |
01:00:53.280
primary board. I'm director of two centers at Harvard and so forth. I do represent the community
link |
01:01:03.520
in various ways. But at the same time, I'm a little bit disappointed by the conservatism that
link |
01:01:08.720
people have. Let me give you an illustration of that. The astronomy community actually is going
link |
01:01:15.280
right now through the process of defining its goals for the next decade. There are proposals for
link |
01:01:22.320
telescopes that would cost billions of dollars and whose goal is to find evidence for oxygen
link |
01:01:30.720
in the atmosphere of planets around other stars. With the idea that this would be a marker, a
link |
01:01:37.680
signature of life. Now, the problem with that is Earth didn't have much oxygen in its atmosphere
link |
01:01:45.360
for the first two billion years. Roughly half of its life. It didn't have much oxygen, but it had
link |
01:01:51.600
life. It had microbial life. It's not clear yet as of yet what the origin is for the rise in the
link |
01:01:59.760
oxygen level after two billion years, about 2.4 billion years ago. But we know that a planet
link |
01:02:08.880
can have life without oxygen in the atmosphere because Earth did it. The second problem with this
link |
01:02:13.840
approach is that you can have oxygen from natural processes. You can break water molecules and make
link |
01:02:21.440
oxygen. So even if you find it, it will never tell you that for sure life exists there. And so even
link |
01:02:28.640
with these billions of dollars, the mainstream community will never be confident whether there
link |
01:02:35.600
is life there. Now, how can it be confident? There is actually a way. If instead of looking with
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01:02:40.560
the same instruments, if you look for molecules that indicate industrial pollution, for example,
link |
01:02:46.800
CFCs that are produced by refrigerating systems or industries here on Earth that they do the
link |
01:02:53.280
ozone layer, you can search for that. And I wrote a paper five years ago suggesting that.
link |
01:02:58.400
Now, what's the problem? You can just tell NASA, I want to build this telescope to search for oxygen
link |
01:03:06.000
but also for industrial pollution. Nobody would say that because it sounds like
link |
01:03:13.520
on the periphery of the field. And I ask you, why would... It's hilarious because that's exactly...
link |
01:03:20.320
That would be saying is quite brilliant because it's a really strong signal. And if life, if there's
link |
01:03:27.680
alien civilizations out there, then there are probably going to be many of them. And they're
link |
01:03:32.880
probably going to be more advanced than us. And they're probably going to have something like
link |
01:03:36.800
industrial pollution, which would be a much stronger signal than some basic gas, which could
link |
01:03:42.560
have a lot of different explanations. So like oxygen or... We could talk about signs of life
link |
01:03:51.280
on Venus and so on. But if you want a strong signal, it'll be pollution. I love how garbage is...
link |
01:03:58.480
No, but the pollution, you have to understand, we think of pollution as a problem. But on a planet
link |
01:04:03.840
that was too cold, for example, to have comfortable life on it, you can imagine terraforming it and
link |
01:04:11.440
putting a blanket of polluting gases such that it will be warmer. And that would be a positive change.
link |
01:04:18.960
So if an industrial or a technological civilization wants to terraform a planet that otherwise is
link |
01:04:27.520
too cold for them, they will do it. So what's the problem of defining it as a search goal
link |
01:04:34.640
using the same technologies? The problem is that there is a taboo. We're not supposed to discuss
link |
01:04:41.760
extraterrestrial intelligence. There is no funding for this subject, not much, very little.
link |
01:04:46.560
And young people, because of the bullying on Twitter, all the social media and elsewhere,
link |
01:04:54.000
young people with talent that are curious about these questions do not enter this field of study.
link |
01:05:00.880
And obviously, if you step on the grass, it will never grow. So if you don't give funding,
link |
01:05:08.320
obviously, the mainstream community says, look, nothing was discovered so far. Obviously,
link |
01:05:12.480
nothing would be discovered. If talented people go to other disciplines, you never search for it
link |
01:05:18.560
well enough, you will never find anything. I mean, look at gravitational wave astrophysics.
link |
01:05:23.600
It's a completely new window into the universe, pioneered by Ray Weiss at MIT. And at first,
link |
01:05:29.840
it was ridiculed. And thanks to some administrators at the National Science Foundation, it received
link |
01:05:36.560
funding despite the fact that the mainstream of the astronomy community was very resistant to it.
link |
01:05:43.600
And now it's considered a frontier. So all these people that I remember as a postdoc,
link |
01:05:48.640
a young postdoc, these people that bashed these fields, said bad things about people,
link |
01:05:52.640
said nothing will come out of it. Now they say, oh, yeah, of course. The Nobel Prize was given
link |
01:05:59.120
to the LIGO collaboration. Of course, now they are supportive of it. But my point is,
link |
01:06:08.880
if you suppress innovation early on, there are lots of missed opportunities.
link |
01:06:16.000
The discovery of exoplanets is one example. In 1952, there was an astronomer named Otto
link |
01:06:23.760
Struve. And he wrote a paper saying, why don't we search for Jupiter, like planets,
link |
01:06:31.440
close to their host star? Because if they're close enough, they would move the star back
link |
01:06:36.480
and forth and we can detect the signal. And so astronomers on time allocation committees of
link |
01:06:43.440
telescopes for 40 years argued, this is not possible, because we know why Jupiter resides
link |
01:06:52.320
so far from the sun. You cannot have Jupiter so close, because there is this region where ice
link |
01:06:57.200
forms far from the sun. And beyond that region is where Jupiter, like planets, can form. There
link |
01:07:02.560
was a theory behind it, which ended up being wrong by today's standards. But anyway,
link |
01:07:08.000
they did not give time on telescopes to search for such systems until the first system was discovered
link |
01:07:14.800
four decades after Otto Struve's paper. And the Nobel Prize was awarded to that
link |
01:07:19.360
just a couple of years ago. And you ask yourself, okay, so science still made progress. What's the
link |
01:07:26.480
problem? The problem is that this baby came out barely and there was a delay of four decades. So
link |
01:07:34.560
the progress was delayed. And I wonder how many babies were not born because of this resistance.
link |
01:07:40.000
So there must be ideas that are as good as this one that were suppressed because they were bullied
link |
01:07:45.040
because people ridiculed them that were actually good ideas. And these are missed opportunities,
link |
01:07:52.560
babies that were never born. And I'm willing to push this frontier of the search for technologies
link |
01:07:59.680
or technological signatures for the civilization. Because when I was young, I was in the military
link |
01:08:06.080
in Israel, it's obligatory to serve. And there was this saying that one of the soldiers sometimes
link |
01:08:12.560
has to put his body on the barbed wire so that others can go through. And I'm willing to suffer
link |
01:08:20.080
the pain so that younger people in the future will be able to speak freely about the possibility that
link |
01:08:27.040
some of the anomalies we find in the sky are due to technological signatures.
link |
01:08:31.600
And it's quite obvious. This is why folks in the artificial intelligence space, Elon Musk and a
link |
01:08:37.440
few others speak about this. And they look at the long arc, they say like, what, you know,
link |
01:08:43.280
this kind of, you know, you can call it like first principles thinking or you can call anything
link |
01:08:48.080
really is like, if we just zoom out from our current bickering and our current
link |
01:08:54.560
like discussions and what science is doing, look at the long arc of the trajectory we're
link |
01:08:59.520
headed at, which questions are obviously fundamental to science and that should be asked. And which
link |
01:09:08.080
is the space of hypothesis we should be exploring. And like exoplanets is a really good example of
link |
01:09:12.880
one that was like an obvious one. I recently talked to Sarah Seeger and it was very taboo when she
link |
01:09:19.040
was starting out to work on an exoplanet and that was even in the 90s. And like it's obvious
link |
01:09:26.160
should not be a taboo subject. And to me, I mean, I'm probably ignorant, but to me exoplanets seems
link |
01:09:31.760
like it's ridiculous that that would ever be a taboo subject to not fund, to not explore.
link |
01:09:37.760
That's very, but even for her, it's now taboo to say like what, you know, to look for industrial
link |
01:09:46.800
pollution, right? Right. I find that ridiculous. I'll tell you why. It's ridiculous for another
link |
01:09:53.440
reason, not because of just the scientific benefits that we might have by exploring it,
link |
01:09:58.720
but because the public cares about these questions and the public funds science. So how dare the
link |
01:10:05.920
scientists shy away from addressing these questions if they have the technology to do it? It's like
link |
01:10:13.680
saying, I don't want to look through Galileo's telescope. It's exactly the same. You have the
link |
01:10:17.520
technology to explore this question, to find evidence and you shy away from it. You might
link |
01:10:23.280
ask why do people shy away from it? And perhaps it's because of the fact that there is science
link |
01:10:28.320
fiction. I'm not a fan of science fiction because it has an element to it that violates the laws
link |
01:10:34.160
of physics in many of the books and the film. And I cannot enjoy these things when I see the
link |
01:10:40.240
laws of physics violated. But who cares that the fact that there is science fiction? I mean,
link |
01:10:46.640
if you have the scientific methodology to address the same subject, I don't care that
link |
01:10:51.280
other people spoke nonsense about this subject or said things that make no sense. Who cares?
link |
01:10:57.520
You do your scientific work just like you explore the dark matter. You explore the possibility that
link |
01:11:04.800
is an artifact. You just look for evidence and try to deduce what it means. And I have no problem
link |
01:11:13.760
with doing that. To me, it sounds like any other scientific question that we have. And given the
link |
01:11:18.160
public's interest, we have an obligation to do that. By the way, science, to me, is not an
link |
01:11:24.240
occupation of the elite. It doesn't allow me to feel superior to other humans that are unable to
link |
01:11:29.280
understand the math. To me, it's a way of life. If there is a problem in the faucet or in the pipe
link |
01:11:36.720
at home, I try to figure out what the problem is. And with a plumber, we figure it out and we
link |
01:11:42.400
look at the clues. And the same thing in science. You look at the evidence, you try to figure out
link |
01:11:47.600
what it means. It's common sense, in a way. And it shouldn't be regarded as something removed
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01:11:55.280
from the public. It should be a reflection of the public's interest. And I think it's actually a
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01:12:00.320
crime to resist the public. If the public says, I care about this. And you say, no, no, no, that's
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01:12:06.320
not sophisticated enough for me. I want to do intellectual gymnastics on anti the sitter
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01:12:10.720
space. To me, that's a crime. Yes. I 100% agree. So it's hilarious that the very, not hilarious,
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01:12:19.280
it's sad that people who are trained in the scientific community to have the tools to explore
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01:12:27.280
this world, to be children, to be the most effective at being children are the ones that
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01:12:32.480
resist being children the most. But there is a large number of people that embrace the childlike
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01:12:41.840
wonder about the world and may not necessarily have the tools to do it. That's the more general
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01:12:47.120
public. And so, I wonder if I could ask you and talk to you a little bit about UFO sightings,
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01:12:56.080
that there's people, quote unquote, believers, there's hundreds of thousands of UFO sightings.
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01:13:03.920
And I've consumed some of the things that people have said about it. And one thing I really like
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01:13:14.640
about it is how excited they are by the possibility, by it's almost like this childlike wonder about
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01:13:23.840
the world out there. It's not a fear, it's an excitement. Do you think, because we're talking
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01:13:30.320
about this possibly extraterrestrial object that visited, that flew by Earth, do you think it's
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01:13:38.320
possible that out of those hundreds of thousands of UFO sightings, one is an actual one or some
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01:13:48.240
number is an actual sighting of a nonhuman to some alien technology? And that we're not,
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01:13:56.880
we're too close minded to look and to see. I think to answer this question, we need better
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01:14:07.280
evidence. My starting point, as I said, out of modesty is that we are not particularly interesting.
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01:14:14.480
And therefore, I would agree, I would be hard pressed to imagine that someone wants to really
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01:14:20.000
spy on us. So I would think, you know, as a starting point that we don't deserve attention,
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01:14:27.040
and we shouldn't expect someone, but who knows. Now, the problem that I have with UFO sighting
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01:14:33.600
reports is that, you know, 50 years ago, there were some reports of fuzzy images, you know,
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01:14:39.120
saucer like things. By now, our technologies are much better, our cameras are much more sensitive.
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01:14:48.000
These fuzzy images should have turned into crisp, clear images of things that we are confident about.
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01:14:55.280
And they haven't turned that way. It's always on the borderline of believability. And because of
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01:15:00.960
that, I believe that it might be most likely artifacts of our instruments, or some natural
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01:15:06.000
phenomena that we are unable to understand. Now, of course, the reason you need, you must examine
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01:15:12.000
those. If, for example, pilots report about them, or the military finds evidence for them,
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01:15:19.840
is because it may pose a national security threat. If another country has technologies that we don't
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01:15:25.280
know about, and they're spying on us, we need to know about it. And therefore, we should examine
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01:15:30.240
everything that looks unusual. But to associate it with an alien life is a little too far for me
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01:15:38.960
until we have evidence that stands up to the level of scientific credence, you know, that
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01:15:46.160
we are 100% sure that, you know, from multiple detectors and, you know, through a scientific
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01:15:53.120
process. Now, again, if the scientific community shies away from these reports, we will never have
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01:15:58.720
that. It's like saying, I don't want to take photographs of something because I know what it
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01:16:04.160
is, then you will never know what it is. But I think if some scientists, if grants, let's put it
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01:16:10.480
this way, if funding will be given to scientists to follow on some of these reports and use scientific
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01:16:17.840
instruments that are capable of detecting those sightings with much better resolution, with much
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01:16:24.240
better information, that would be great because it will clarify the matter. You know, these are not,
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01:16:29.520
as you said, you know, hundreds of thousands, these are not the ones in the lifetime events.
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01:16:34.160
So it's possible to take scientific instrumentation and explore, go to the ocean where the,
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01:16:40.800
you know, someone reported that there are frequent events that are unusual and check it out, do a
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01:16:47.360
scientific experiment. What's the problem? Why not? Why only do experiments deep into the ocean and
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01:16:51.920
look at the oceanography or do other things? You know, we can do scientific investigation of these
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01:16:59.360
sightings and figure out what they mean. I'm very much in favor of that. But until we have the
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01:17:05.600
evidence, I would be doubtful as to what they actually mean. Yeah, we'll have to be humble
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01:17:11.200
and acknowledge that we're not that interesting. It's kind of, you're making me realize that
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01:17:16.240
because it's so taboo that the people that have the equipment, meaning, and we're not just talking,
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01:17:22.160
everybody has cameras now, but to have a large scale like sensor network that collects data,
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01:17:31.360
that regularly collects, just like we look at the weather, we're collecting information,
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01:17:35.200
and then we can then access that information when there is reports and like have it not be a taboo
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01:17:40.320
thing where there's like millions or billions of dollars funding this effort, that by the way,
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01:17:46.640
inspires millions of people. This is exactly what you're talking about. It's like the scientific
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01:17:53.360
community is afraid of a topic that inspires millions of people. It's absurd. But if you put
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01:17:59.200
blinders on your eyes, you don't see it. Yeah, right. I should say that we do have meteors that
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01:18:06.080
we see. These are rocks that by chance happen to collide with the Earth. And if they're small,
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01:18:13.360
they burn up in the atmosphere. But if they're big enough, tens of meters or more, hundreds of
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01:18:19.600
meters, the outer layer burns up, but then the core of the object makes it through. And this is our
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01:18:28.000
chance of putting our hands around an object if this meteor came from interstellar space. So
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01:18:34.480
one path of discovery is to search for interstellar meteors. And with the student of mine, we actually
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01:18:42.400
looked through the record and we thought that we found one example of a meteor that was reported
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01:18:47.840
that might have come from interstellar space. And another approach is, for example, to look at the
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01:18:55.040
moon. The moon is different from the Earth in the sense that it doesn't have an atmosphere. So objects
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01:19:00.800
do not burn up on their way to it. It's sort of like a museum. It collects everything that comes
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01:19:06.880
of rocks from out there. Yeah, deep space. Yeah. And there is no geological activity on the moon.
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01:19:11.760
So on Earth, every 100 million years, you know, we could have had computer terminals on Earth that
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01:19:17.360
could have been a civilization like ours with electronic equipment more than 100 million years
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01:19:23.200
ago. And it's completely lost. You cannot excavate and find it evidence for it because in archaeological
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01:19:29.920
digs, because the Earth is being mixed on these time scales. And everything that was on the surface
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01:19:36.240
more than 100 million years ago is buried deep inside the Earth right now because of geological
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01:19:40.800
activity. Fascinating to think about, by the way. Yeah. But on the moon, this doesn't happen. The only
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01:19:45.600
thing that happens on the moon is you have objects impacting the moon and they go 10 meters deep,
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01:19:51.600
so they produce some dust. But the moon keeps everything. It's like a museum. It keeps everything
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01:19:56.400
on the surface. So if we go to the moon, I would highly recommend regarding it as an archaeological
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01:20:03.760
site and looking for objects that are strange. Maybe it collected some trash, you know, from
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01:20:09.920
interstellar space. If we could just link it on the Drake equation for a little bit. We kind of
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01:20:15.760
talked about there's a lot of uncertainty in the parameters and the Drake equation itself is very
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01:20:22.640
limited. But I think the parameters are interesting in themselves, even if it's limited, because I
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01:20:29.120
think each one is within the reach of science, right? Did you get the evidence for it? I mean,
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01:20:34.400
a few I find really interesting. It's interesting to get your comment on. So the one with the most
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01:20:41.200
variants, I would say from my perspective, is the length that civilizations last. However you
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01:20:47.920
define it. In the Drake equation, it's the length of how long you're communicating, just like transmitting.
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01:20:53.520
Just like you said, that's a wrong way to think about it, because we can be detecting
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01:20:59.120
some other outputs of the civilizations, etc. But just if we just define broadly how long those
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01:21:04.240
civilizations last, do you have a sense of how long that might last? Like what are the great
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01:21:12.160
filters that might destroy civilizations that we should be thinking about? How can science
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01:21:19.840
give us more hints on this topic? So I, as I mentioned before, operate by the Copernican
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01:21:25.760
principle, meaning that we are not special. We don't live in a special place and not in a special
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01:21:32.800
time. And by the way, it's just modesty and encapsulated in scientific terms, right? You're
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01:21:39.200
saying I'm not special, you know, I find conditions here, they exist everywhere. So if you adapt the
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01:21:45.120
Copernican principle, you basically say our civilization transmitted radio signals for 100
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01:21:53.280
years, roughly. So probably it would last another 100 or a few hundred and that's it,
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01:22:00.480
because we don't live at a special time. So that's, you know, well, of course, if we get our act
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01:22:07.360
together, and we somehow start to cooperate rather than fighting each other, killing each other,
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01:22:14.640
you know, wasting a lot of resources on things that would destroy our planet,
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01:22:21.280
maybe we can lengthen that period if we get smarter. But the most natural assumption is to
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01:22:28.480
say that we will live into the future as much as we lived from the time that we start to develop
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01:22:34.400
the means for our own destruction, the technologies we have, which is quite pessimistic, I must say.
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01:22:39.680
So several centuries, that's what I would give, not unless we get our act, unless we become more
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01:22:44.880
intelligent than the newspapers report every day. Okay, point number one. Second, and by the way,
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01:22:51.920
this is relevant, I should say, because there was a report about perhaps a radio signal detected
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01:22:58.480
from Proxima Centauri. What do you make of that signal? Oh, I think it's some Australian guy with
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01:23:03.520
a cell phone next to the observatory or something like that, because it was the park's telescope
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01:23:09.120
in Australia. Okay. So it's human created noise. Yeah, which is always the worry, because actually
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01:23:17.120
the same observatory, the park's observatory detected a couple of years ago some signal,
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01:23:23.360
and then they realized that it comes back at lunch lunchtime. Yes. And they said, okay,
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01:23:29.760
what could it be? And then they figured out that it must be the microwave oven in the observatory,
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01:23:33.920
because someone was opening it before it finished, and it was creating this radio signal that they
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01:23:40.080
detected with a telescope every lunchtime. So just a cautionary remark. But the reason I think
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01:23:48.080
it's human made, without getting to the technical details, is because of this very short window by
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01:23:54.720
which we were transmitting radio signals out of the lifetime of the earth. You know, as I said,
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01:23:59.120
100 years out of four and a half billion years that the earth existed. So what's the chance that
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01:24:05.040
another civilization, a twin civilization of ours, is transmitting radio signals exactly at
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01:24:10.720
the time that we are looking with our radio telescopes, 10 to the minus seven, you know.
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01:24:17.440
So, and the other argument I have that is that they detected it in a very narrow band of frequencies,
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01:24:25.840
and that makes it, you know, it cannot be through natural processes, a very narrow band,
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01:24:31.760
just like some radio transmissions that we produce. But if it were to come from the habitable zone,
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01:24:40.560
from a transmitter on the surface of Proxima B, this is the planet that orbits Proxima Centauri,
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01:24:46.880
then I calculated that the frequency would drift through the Doppler effect, you know,
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01:24:51.920
just like when you hear a siren on the street, you know, when the car approaches you,
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01:24:57.920
it has a different pitch than when it goes, recedes away from you. That's the Doppler effect.
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01:25:02.960
And when the planet orbits the star, Proxima Centauri, you would see or detect a different
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01:25:10.480
frequency when the planet approaches us as compared to when it recedes. So there should be a frequency
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01:25:15.600
drift just because of the motion of the planet. And I calculated that it must be much bigger than
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01:25:25.120
observed. So it cannot just be a transmitter sitting on the planet and sending in our direction,
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01:25:30.480
a radio signal, unless they want to cancel the Doppler effect, but then they need to know about
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01:25:37.280
us, because in a different direction, it will not be canceled. Only in our direction, they can
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01:25:41.040
cancel it perfectly. So there is this direction of Proxima Centauri, but I have a problem imagining
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01:25:49.600
a transmitter on the surface of a planet in the habitable zone emitting it. But my main issue
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01:25:56.800
is really with a likelihood, given what we know about ourself.
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01:26:01.680
Right. In terms of the duration of the civilization.
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01:26:03.840
The Copernican principle, yeah.
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01:26:05.200
So nevertheless, this particular signal is likely to be a human interference, perhaps, but
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01:26:12.400
do you find Proxima be interesting? Or the more general question is, do you think we humans
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01:26:20.880
will venture out into outside our solar system and potentially colonize other habitable planets?
link |
01:26:30.240
Actually, I am involved in a project whose goal is to develop the technology that
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01:26:34.880
would allow us to leave the solar system and visit the nearest stars. And that is called the
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01:26:40.400
Starshot. In May 2015, an entrepreneur from Silicon Valley, Yuri Milner, came to my office
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01:26:48.880
at Harvard and said, would you be interested in leading a project that would do that in our lifetime?
link |
01:26:57.760
Because as we discussed before, to traverse those distances with existing rockets would take
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01:27:04.000
tens of thousands of years. And that's too long. For example, to get to Proxima Centauri with
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01:27:12.880
the kind of spacecrafts that we already sent, like New Horizons or Voyager 1, Voyager 2,
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01:27:20.400
you needed to send them when the first humans left Africa, so that they would arrive there now.
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01:27:27.840
And that's a long time to wait. So Yuri wanted to do it within our lifetime, 10, 20 years,
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01:27:34.960
meaning it has to move at a fraction of the speed of light. So can we send a spacecraft that would
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01:27:40.640
be moving at a fraction of the speed of light? And I said, let me look into that for six months.
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01:27:46.880
And with my students and postdocs, we arrived to the conclusion that the only technology that
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01:27:51.520
can do that is the light sail technology, where you basically produce a very powerful laser beam
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01:28:00.240
on Earth. So you can collect sunlight with photovoltaic cells or whatever, and then convert it into
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01:28:12.160
stored energy and then produce a very powerful laser beam that is 100 gigawatts
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01:28:17.200
and focus it on a sail in space that is roughly the size of a person, a couple of meters or a few
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01:28:28.080
meters, that weighs only a gram or a few grams, very thin. And through the math, you can show that
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01:28:37.600
you can propel such a sail, if you shine on it for a few minutes, it will traverse a distance
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01:28:42.640
that is five times the distance to the moon, and it will get to a fifth of the speed of light.
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01:28:47.440
Sounds crazy, but I've talked to a bunch of people and they're like, I know it sounds crazy,
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01:28:52.480
but it's actually, it will work. This is one of those, it's just beautiful. I mean, this is science.
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01:28:59.840
And the point is, people didn't get excited about space since the Apollo era. And it's about time,
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01:29:09.040
you know, for us to go into space. A couple of months ago, I was asked to participate in a debate
link |
01:29:15.360
organized by IBM and Bloomberg News, and the discussion centered on the question,
link |
01:29:22.160
is the space race between the US and China good for humanity? And all the other debaters
link |
01:29:29.840
were worried about the military threats. And I just couldn't understand what they're talking about,
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01:29:35.920
because military threats come from hovering above the surface of the earth, right? And
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01:29:43.040
we live on a two dimensional surface, we live on the surface of the earth,
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01:29:46.480
but space is all about the third dimension getting far from Earth. So if you go to Mars,
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01:29:51.600
or you go to a star, another star, there is no military threat. What are we talking about?
link |
01:29:56.880
Space is all about, you know, feeling that, you know, we are one civilization, in fact,
link |
01:30:03.120
not fighting each other, just going far and having aspirations for something that goes
link |
01:30:08.480
beyond military threats. So why would we be worried that the space race will lead?
link |
01:30:14.560
That's actually brilliant. You know, in our discourse about it, the space race is sometimes
link |
01:30:21.120
made synonymous with like the Cold War, something like that, or with wars. But really, yeah, there
link |
01:30:26.400
was a lot of ego tied up in that. I remember, I mean, it's still, still to this day, there's a
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01:30:31.040
lot of pride that Russians, the Soviet Union was the first to space. And there's a lot of pride in
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01:30:35.440
the American side that was the first on the moon. But yeah, you're exactly right. Like,
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01:30:39.680
there's no aggression. There's no wars. And beyond that, if you think about the global economy
link |
01:30:45.200
right now, there is a commercial interest. That's why Jeff Bezos and Elon Musk are interested about,
link |
01:30:51.440
you know, Mars and so on. There is a commercial interest which is international. It's not,
link |
01:30:55.360
it's driven by money, not by pride. And, you know, nations can sign treaties. First of all,
link |
01:31:03.440
there are lots of treaties that were signed even before the First World War and the Second World
link |
01:31:07.360
War and the World War took place. So who cares, you know, like humans, treaties do not safeguard
link |
01:31:13.840
anything, you know. But beyond that, even if nations sign treaties about space exploration,
link |
01:31:19.600
you might still find commercial entities that will find a way to get their launches. And,
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01:31:26.320
you know, so I think we should rethink space. It has nothing to do with national pride. Once
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01:31:32.240
again, nothing to do with our egos. It's about exploration. And the biggest problem, I think,
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01:31:38.640
to human, in human history is that, is that humans tend to think about egos and about their,
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01:31:45.760
their, their own personal image rather than look at the big picture. You know,
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01:31:54.720
we will not be around for long. We are just occupying a small space right now. Let's move
link |
01:32:00.160
out of this, you know, the way that Oscar Wilde said, I think is the best. He said,
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01:32:05.920
all of us are in the gutters, but some of us are looking at the stars.
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01:32:10.560
Yeah. And the more of us are looking at the stars, the likelier we are to, uh, to this,
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01:32:17.360
for this thing, for this little experiment we have going on to last, last a while, as opposed
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01:32:22.800
to end too quickly. I mean, it's not just about science of being humble. It's, it's about the
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01:32:27.920
survival of the human species is being, is being humble. To me, it's incredibly inspiring, the
link |
01:32:34.240
Starshop project of, I mean, there's something magical about being able to go to another habitable
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01:32:40.800
planet and take a picture even. I mean, within our lifetime, I mean, that, that, uh, with crazy
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01:32:47.600
technology too, which I should tell you how it was conceived. So, um, I was at the time, um,
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01:32:54.560
so after six months past, after the visit of Urimillah, uh, I was usually I go in December
link |
01:33:01.440
during the winter break, I go to Israel. Um, I used to go to see my family and, uh, I get a phone call.
link |
01:33:09.120
Um, just before the weekend started, they get a phone call. Uh, Yuri would like you to present
link |
01:33:15.280
your concept, um, in two weeks at his home. And I said, well, uh, thank you for letting me know,
link |
01:33:22.320
because I'm actually out of the door of the hotel to go to a goat farm in the negative,
link |
01:33:29.040
in the southern part of Israel with, because my wife wanted to have sort of, um, to go to a place
link |
01:33:35.520
that is removed from civilization, so to speak. So we went to that goat farm and, you know,
link |
01:33:42.960
I need to make the presentation and, um, there was no internet connectivity except in the office
link |
01:33:49.360
of the goat farm. So the following morning at six a.m., I sit with my back to the office of
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01:33:55.680
that goat farm looking at goats that were newly born and, uh, typing into my laptop the presentation,
link |
01:34:02.800
you know, the PowerPoints presentation about, you know, our ambitions for visiting the nearest
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01:34:07.520
star. And that was very surreal to me that, um, you know, look. Oh, like our origins in many ways,
link |
01:34:16.560
this very primitive origins and, uh, our dreams of looking out that it's brilliant. So that is
link |
01:34:23.280
incredibly inspiring to me, but it's also inspiring of putting humans onto other, um, moons or
link |
01:34:33.520
planets. I still find going to the moon really exciting. I don't know, maybe I'm just a sucker
link |
01:34:38.560
for it, but it's really exciting. And Mars, which is a new place, a new planet, another
link |
01:34:44.560
planet that might have life. I mean, there's something magical to that or some traces of
link |
01:34:49.120
previous life. You might think that humans cannot really survive. Uh, and, and there are risks
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01:34:54.080
by going there. But my point is, you know, we started from Africa and we got to apartment
link |
01:35:01.120
buildings in Manhattan, right? It's a very different environment from the jungles to
link |
01:35:06.240
live in an apartment building in, you know, a small cubicle. Um, and, you know, it took
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01:35:12.320
tens of thousands of years, but humans adapted, right? So why couldn't humans also make the leap
link |
01:35:18.880
and adapt to a habitat in space? You know that now you can build a platform that would look like
link |
01:35:24.880
an apartment building in the Bronx or somewhere, but have inside of it everything that humans need.
link |
01:35:32.400
And it just like the space station, but bigger and it will be a platform in space. And the
link |
01:35:37.520
advantage of that is if something bad happens on earth, you have that complex where humans live.
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01:35:45.280
And you can also move it back and forth depending on how bright the sun gets. Uh, because, you know,
link |
01:35:50.960
within, within a billion years, within a billion years, the sun would be too hot and it will boil
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01:35:58.160
off all the oceans on earth. So we cannot stay here for more than a billion years. That's for sure.
link |
01:36:02.800
Yes. So that's a billion years from now. Uh, I prefer like shorter term deadlines. And so
link |
01:36:09.840
in, in that's, I mean, there's a lot of threats that we're facing currently. Do you find it exciting
link |
01:36:13.840
the possibility of, uh, you know, uh, landing on Mars and starting little like, uh, building a
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01:36:21.440
Manhattan style apartment building on Mars and humans occupying it? Do you think from a scientific
link |
01:36:27.120
or an engineering perspective that's, uh, that's a worthy pursuit? I think it's worthy, but the
link |
01:36:32.960
real issue that is often, uh, underplayed is the risk to the human body from cosmic rays.
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01:36:40.480
Right. These are energetic particles and we are protected from them by the magnetic field around
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01:36:47.920
the earth, uh, that blocks them. But if you go to Mars where there is no such magnetic field to
link |
01:36:54.560
block them, then, um, you know, a significant fraction of the brain cells in your, your head
link |
01:37:00.320
will be damaged within a year. And the consequences of that are not clear. I mean, uh, it's quite
link |
01:37:07.840
possible that humans cannot really survive on the surface. Now it may mean that we need to dig
link |
01:37:13.840
tunnels, uh, go underground or create some protection. Uh, this is something that can be engineered.
link |
01:37:20.720
Yes. Uh, and, you know, we can start from the moon and then move to Mars. That would be a natural
link |
01:37:25.760
progression, but it's a big, uh, issue that needs to be dealt with. I don't think, you know, it's
link |
01:37:32.400
a showstopper. I think we can overcome it, but, you know, just like anything in science and technology,
link |
01:37:38.160
you have to work on it for a while, figure out solutions. And, but it's not as rosy as Elon
link |
01:37:44.080
Musk talks about. I mean, Elon Musk can obviously be optimistic. I think eventually it will boil
link |
01:37:49.840
down to figuring out, um, how to cope with this risk, the health risk. Yeah. I mean, uh, in defense
link |
01:37:56.080
of optimism, I, I find that there's at least a correlation, if not their best friends is optimism
link |
01:38:03.200
and open mindedness is, uh, it's a necessary, it's precondition to do, to do, to try crazy things.
link |
01:38:14.000
And, uh, in that sense, there, uh, the sense I have about going to Mars, if we use today's logic
link |
01:38:21.280
of what kind of benefits we'll get from that, we're never going to go. Uh, and like most decisions
link |
01:38:29.760
we'll make in life, most decisions we've made as a human species are irrational. If you just,
link |
01:38:37.360
if you look at just today, but if you look at the long arc and the possibilities that it might bring,
link |
01:38:43.920
just like humans, uh, uh, Europe and Europe and, and, and by the way, it was destroyed everybody
link |
01:38:50.800
and, uh, but it was a commercial interest that drove that, uh, for trade. And you know, it might
link |
01:38:57.360
happen again in this context. You have people like Jeff Bezos and Elon Musk that are commercially
link |
01:39:02.000
driven to go to space. Yes. But it doesn't mean that what we will ultimately find is not new worlds,
link |
01:39:09.280
you know, that have nothing, you know, much, have much more to offer than just commercial interest.
link |
01:39:15.120
And, uh, as a side effect almost, right? Yeah. Yeah. And then that's why I think, you know,
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01:39:20.880
we should be open minded and explore. And however, at the same time, because of the reasons you
link |
01:39:26.240
pointed out, uh, I'm not optimistic that we will survive more than a few centuries into the future,
link |
01:39:32.080
because people do not think long term. And that means that we will only survive for the short
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01:39:37.520
term. I don't know if you have thoughts about this, but what are the things that were you the most
link |
01:39:42.640
about, uh, from the great perspective of the universe, which is the great filters that destroys
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01:39:48.320
intelligence civilizations, but for our own species here, uh, like what are the things that
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01:39:54.080
worry you the most? Yeah. The thing that worries me the most is that people pay attention to how
link |
01:39:58.880
many likes they have on Twitter. And, uh, rather than, you know, basketball coaches tell the team
link |
01:40:07.600
players, keep your eyes on the ball, not on the audience. The problem is we keep our eyes
link |
01:40:14.640
on the audience most of the time. Let's keep our eyes on the ball. And what does that mean?
link |
01:40:19.680
First of all, in context of science, it means pay attention to the evidence. When the evidence looks
link |
01:40:25.520
strange, then we should figure it out. You know, I went to a seminar about Uumuamua at Harvard
link |
01:40:33.920
and a colleague of mine that is a mainstream conservative would never say anything that would
link |
01:40:42.560
deviate from what everyone else is thinking, said to me after the seminar, I wish this object
link |
01:40:49.760
never existed. Now, to me, I mean, I just couldn't hear that. What do you mean? Nature is whatever
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01:40:57.520
it is. You have to pay attention to it. You cannot say, you know, you cannot bury your head in this.
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01:41:03.200
I mean, you should bless nature for giving you clues about things that you haven't expected.
link |
01:41:08.240
And I think that's the biggest fault that we are looking for confirmations of things we already know
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01:41:15.360
so that we can maintain our pride that we already knew it and maintain our image,
link |
01:41:22.480
not make mistakes because we already knew it. Therefore, we expected the right thing. But
link |
01:41:27.360
science is a learning experience and sometimes you're wrong. And let's learn from those mistakes.
link |
01:41:33.120
And what's the problem about that? Why do we have to get prizes and why do we get to be
link |
01:41:39.360
honoured and maintain our image when the actual objective of science is learning about nature?
link |
01:41:45.920
You've talked about anomalies in this case are actually not things that are unfortunate and to
link |
01:41:52.560
be ignored are in fact gifts and should be the focus of science. Exactly, because that's the
link |
01:41:57.760
way for us to improve our understanding. If you look at quantum mechanics, nobody dreamed about it.
link |
01:42:03.280
And it was revolutionary and we still don't fully understand it. It's a pain for us to figure out.
link |
01:42:09.120
So why do you think so? I understand from the science from the perspective of that's holding
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01:42:12.880
our science back. Why do you ever sense that that's also something that might be a problem for us in
link |
01:42:21.120
terms of the survival of human civilization? Because when you look at society, it operates
link |
01:42:26.880
by the same principles. There is a people look for affirmation by groups and they,
link |
01:42:37.200
you know, people segregate into herds that think like them, especially these days when
link |
01:42:41.440
social media is so strong, you can find your support group. And if you don't look for evidence
link |
01:42:47.520
for what you're saying, you can say crazy things. As long as there are enough people supporting what
link |
01:42:52.240
you say, you can even have your newspapers. You can have everything to support your view.
link |
01:42:58.400
And then, you know, bad things will happen to society because we're detaching ourselves from
link |
01:43:02.720
reality. And if we detach ourselves from reality, all the destructive things that naturally can
link |
01:43:08.000
occur in the real world, whether from nuclear weapons, all the kinds of threats that we're
link |
01:43:12.560
facing, even we're living through a pandemic, the supposed, you know, a much, much worse pandemic
link |
01:43:19.920
can happen. And then we could sadly, like we did this one, politicize it in some kind of way and
link |
01:43:25.760
have bickering in the space of Twitter and politics as opposed to there's an actual thing that can
link |
01:43:31.840
destroy the human species. Exactly. So the only way for us to maintain, to stay modest and learn
link |
01:43:37.520
about what really happens is by looking for evidence. Again, I'm saying it's not about our
link |
01:43:44.000
self, you know, it's about figuring out what's around us. And if you close yourself by surrounding
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01:43:50.000
yourself with people that are like minded, that refuse to look at the evidence, you can do bad
link |
01:43:56.800
things. And throughout human history, that's the origin of all the bad things that happen.
link |
01:44:03.520
Yes. And I think it's a key. It's a key to be modest and to look at evidence. And it's not a
link |
01:44:09.200
nuance. Now, you might say, Oh, okay, the uneducated person might operate. No, it's the
link |
01:44:16.720
scientific community operates this way. My problem is not with people that don't have an
link |
01:44:22.560
academic pedigree. It's included everywhere in society. On the topic of the discovery of
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01:44:29.840
evidence of alien civilizations, which is something you touch on in your book, what that
link |
01:44:34.880
idea would do to societies, to the human psyche. And in general, do you think,
link |
01:44:42.800
and you talk about the, I still have trouble pronouncing, but a more, more wager, right? What
link |
01:44:51.760
do you think is, can you explain it? And what do you think in general is the effect that such
link |
01:44:57.120
knowledge might have on human civilization? Right. So Pascal had this wager about God.
link |
01:45:03.440
And by the way, there are interesting connections between theology and the search for extraterrestrial
link |
01:45:08.560
life. You know, it's possible that, you know, we were planted on this planet by another civilization
link |
01:45:14.640
that, you know, we attribute to God powers that are that belong really to the technological
link |
01:45:20.080
civilization. But putting that aside, Pascal basically said, you know, let's, the two possibilities,
link |
01:45:27.840
either God exists or not, right? And if God exists, you know, the consequences are quite
link |
01:45:35.360
significant. And therefore, you know, we should, we should consider that possibility differently
link |
01:45:41.520
than equal weight to both possibilities. And I suggest that we do the same with Oumuamua or
link |
01:45:51.280
other technological signatures that we keep in mind the consequences. And therefore,
link |
01:45:59.360
pay more attention to that possibility. Now, some people say, extraordinary claims require
link |
01:46:05.520
extraordinary evidence. My point is that the term extraordinary is really subjective, you know.
link |
01:46:12.800
For one person, a black hole is extraordinary. For another, you know, it's just a consequence
link |
01:46:18.800
of Einstein's theory of gravity. It's nothing extraordinary. The same about the type of dark
link |
01:46:25.040
matter or anything. So we should leave the extraordinary part of that sentence. Just
link |
01:46:32.400
keep evidence. Okay, so let's be guided by evidence. And even if we have extraordinary
link |
01:46:38.720
claims, you know, let's not dismiss them because the evidence is not extraordinary enough, because
link |
01:46:44.000
if we have an image of something, and it looks really strange, and we say, oh, the image is not
link |
01:46:49.200
sufficiently sharp. Therefore, we should not even pay attention to this image or not even consider.
link |
01:46:54.400
I think that's a mistake. What we should do is say, look, there is some evidence for something
link |
01:46:59.120
unusual. Let's try and build instruments that will give us a better image. And if you just dismiss
link |
01:47:06.160
extraordinary claims, because you consider them extraordinary, you avoid discovering things that
link |
01:47:12.880
you haven't expected. And so I believe that along the history of astronomy, there are many missed
link |
01:47:19.920
opportunities. And I speak about astronomy, but I'm sure in other fields, it's also true. I mean,
link |
01:47:24.320
this is my expertise. For example, you know, the astrophysical journal, which is the main primary
link |
01:47:30.320
publication in astrophysics. If you go, you go beyond before the 1980s, there are images that
link |
01:47:37.680
were posted in the astrophysical journal of giant arcs, you know, arcs of light surrounding clusters
link |
01:47:45.040
of galaxies. And, you know, you can find it in printed versions of the astrophysical journal,
link |
01:47:51.520
people just ignore, they put the image, they see the arc, they say, who knows what it is and just
link |
01:47:57.360
ignore it. And then in the 1980s, the subject of gravitational lensing became popular. And the
link |
01:48:05.920
idea is that you can deflect light by the force of gravity. And then you can put a source behind
link |
01:48:14.320
the cluster of galaxies, and then you will get these arcs. And actually Einstein predicted it
link |
01:48:18.800
in 1940. And, you know, so these things were expected, but people just had them in the images,
link |
01:48:26.880
didn't pay attention. So I'm sure there are lost opportunities sometimes, even in existing data,
link |
01:48:31.760
you have things that are unusual and exceptional, and they're not being addressed.
link |
01:48:37.680
Yeah, you actually, I think you have the article, the data is not enough from quite a few years ago,
link |
01:48:44.080
where you talk, you know, we can go back to the 70s and 80s, but we can go also to the Mayan
link |
01:48:49.600
civilization. Right, the Mayan civilization basically believed in astrology that you can
link |
01:48:54.640
forecast the outcome of a war based on the position of the planets. And they had, you know,
link |
01:49:01.280
astronomers in their culture had the highest social status. They were priests, they were
link |
01:49:08.240
elevated. And the reason was that they helped politicians decide when to go to war, because
link |
01:49:14.160
they would tell the politicians, you know, the planets would be in this configuration,
link |
01:49:18.240
it's a better chance for you to win the war, go to war. And in retrospect, they collected wonderful
link |
01:49:25.200
data, but misinterpreted it, because we now know that the position of Venus, or Jupiter, or whatever,
link |
01:49:32.400
has nothing to do with the outcome of World War I, World War II, you know, has nothing to do. And
link |
01:49:39.600
so we can have a prejudice and collect data without actually doing the right thing with it.
link |
01:49:46.240
That's such a Pisces thing to say. I looked up what your astrological sign is.
link |
01:49:54.000
So you mentioned Einstein predicted that black holes don't exist,
link |
01:49:57.440
or just don't exist in nature. When Einstein came up with this theory of gravity in 1915,
link |
01:50:04.320
November 1915, a few months later, another physicist, Karl Schwarzschild, he was the
link |
01:50:12.000
director of the Potsdam Observatory, but he was a patriot, a German patriot. So he went into the
link |
01:50:16.880
First World War fighting for Germany. But while he was at the front, he sent a postcard to Einstein
link |
01:50:23.120
saying, you know, a few months after the theory was developed, saying, actually, I found a solution
link |
01:50:27.120
to your equations. And that was a black hole solution. And then he died a few months later.
link |
01:50:33.520
And Einstein was a pacifist, and he survived. So the lesson from this story is that if you want to
link |
01:50:39.280
work out the consequences of a theory, you better be a pacifist. But the point is that
link |
01:50:47.200
this solution was known shortly after Einstein came up with his theory. But in 1939, Einstein
link |
01:50:54.560
wrote a paper in the analysis of mathematics saying, even though the solution exists,
link |
01:51:00.000
I don't think it's realized in nature. And his argument was, if you imagine a star collapsing,
link |
01:51:06.880
stars often spin, and the spin will prevent them from making a black hole,
link |
01:51:11.280
collapsing to a point. So I mean, can you maybe one of the many things you you have worked on,
link |
01:51:19.120
you're an expert in black holes? Can you first say what are black holes? And second,
link |
01:51:24.960
how do we know that they exist? Right. So black holes are the ultimate prison.
link |
01:51:31.520
You know, you can check in, but you can never check out. Even light cannot escape from them.
link |
01:51:38.160
So there are extreme structures of space and time. And there is this so called Schwarzschild
link |
01:51:44.720
radius or the event horizon of a black hole. Once you enter into it with a spaceship,
link |
01:51:52.480
you would never be able to tweet back to your friends and tell them, by the way,
link |
01:51:56.960
I asked the students in my class, Freshman seminar at Harvard, I said,
link |
01:52:01.200
let me give you two possible journeys that you can take. I said, suppose aliens come to earth
link |
01:52:07.680
and suggest that you would board our spaceship, would you do it? And the second is suppose you
link |
01:52:16.160
could board a spaceship that will take you into a black hole, would you do it? So all of them said
link |
01:52:22.320
to the first question, yes, under one condition, that I'll be able to maintain my social media
link |
01:52:29.280
contacts and report back, share the experience with them. I couldn't personally, I have no footprint
link |
01:52:35.520
on social media. Yeah, which is as a matter of principle. Yeah, my wife asked me when we got
link |
01:52:41.120
married. And I honoured that. And I told you offline, I need to get married to such a woman.
link |
01:52:48.160
She truly is a special lady. Well, she was wise enough to recognise the risk. But it saves me time.
link |
01:52:55.120
And it also keeps me away from crowds. You know, I don't have the notion of what a lot of other
link |
01:53:02.320
people think. So I can think independently. Exactly. So I was surprised to hear that for
link |
01:53:09.760
students, it's extremely important to share experiences. Even if they go on a spaceship
link |
01:53:13.920
with aliens, they still want to brag about it rather than look around and see what's going on.
link |
01:53:19.680
This is not an option when you go to the black hole. It's exactly the point.
link |
01:53:22.960
So for the black hole, they said no, because obviously you can find your death after you
link |
01:53:29.440
get into it. You crash in the singularity. There is this singularity in the centre. So
link |
01:53:34.880
inside the event horizon, we know that all the matter collects at a point. Now, we can't really
link |
01:53:43.360
predict what happens at the singularity because Einstein's theory breaks down. And we know why
link |
01:53:49.040
it breaks down because it doesn't have quantum mechanics that talks about small distances.
link |
01:53:53.280
We don't have a theory that unifies quantum mechanics and gravity so that it will predict
link |
01:53:59.600
what happens near a singularity. And in fact, you know, I once, a couple of years ago, I had a
link |
01:54:06.400
flood in my basement. I mean, and I invited a plumber to come over and figure out. And we
link |
01:54:14.800
found that the sewer was clogged because of tree roots that got into it. And we solved the problem.
link |
01:54:23.440
But then I thought to myself, well, isn't that what happens to the singularity of a black hole?
link |
01:54:30.640
Because the question is, where does the matter go? You know, in the case of a home, I never
link |
01:54:37.360
thought about it. But the water, all the water that we use goes in through the sewer to some
link |
01:54:42.880
reservoir somewhere. And the question is, what happens inside a black hole? And one possibility
link |
01:54:49.280
is that there is an object in the middle, just like a star, you know, and everything collects
link |
01:54:53.120
there. And the object has the maximum density that we can imagine, like Planck density. It's
link |
01:54:58.720
the ultimate density that you can have, where gravity is as strong as all the other forces.
link |
01:55:07.120
So you can imagine this object, very dense object at the center that collects all the matter.
link |
01:55:12.000
Another possibility is that there is some tunnel just like the sewer. It takes the matter into
link |
01:55:17.920
another place. And we don't know the answer. But I wrote a Scientific American essay about it,
link |
01:55:25.200
admitting our ignorance. It's a fascinating question. What happens to the matter that goes
link |
01:55:29.120
into a black hole? I actually recommended to some of my colleagues that work on string theory
link |
01:55:34.960
at the closing of a conference. I'm the founding director of the Black Hole Initiative
link |
01:55:39.200
at Harvard, which brings together astronomers, physicists, philosophers, and mathematicians.
link |
01:55:44.320
And we have a conference once a year. And at the end of one of them, since I'm the director,
link |
01:55:49.520
I had to summarize and I said that I wish we could go on a field trip to a black hole nearby.
link |
01:55:57.840
And I highly recommend to my colleagues that work on string theory to enter into that black hole,
link |
01:56:03.680
because then they can test their theory when they get inside. But one of the string theories
link |
01:56:09.680
in the audience, Nimar Khani Hamid, immediately raised his voice and said, you have an ulterior
link |
01:56:15.200
motive for sending us into a black hole, which I didn't deny, but at any event.
link |
01:56:23.680
Yeah, that's true. That's true. Can you say why we know that black holes exist?
link |
01:56:31.600
Right. So it's an interesting question because black holes were considered a theoretical construct.
link |
01:56:40.720
And Einstein even denied their existence in 1939. But then in the mid 1960s,
link |
01:56:51.120
quasars were discovered. These are very bright sources of light,
link |
01:56:55.440
a hundred times brighter than their host galaxy, which are point like at the center of galaxies.
link |
01:57:03.520
And it was immediately suggested by Ed Salpeter in the West and by Yakov Zeldovich in the East,
link |
01:57:14.080
that these are black holes that accrete gas, collect gas from their host galaxy that are
link |
01:57:20.560
being fed with gas. And they shine very brightly because as the gas falls towards the black holes,
link |
01:57:28.400
just like water running down the sink, the gas swirls and then rubs against itself and heats up
link |
01:57:40.640
and shines very brightly because it's very hot close to the black hole by viscosity.
link |
01:57:47.360
It heats up. And in the case of black holes, it's the turbulence, the turbulent viscosity
link |
01:57:53.760
that causes it to heat up. So we get these very bright sources of light just from black holes
link |
01:58:00.000
that are supposed to be dark. Nothing escapes from them, but they create a violent environment
link |
01:58:06.800
where gas moves close to the speed of light and therefore shines very brightly,
link |
01:58:11.280
much more than any other source in the sky. And we can see these quasars all the way to
link |
01:58:16.240
the edge of the universe. So we have evidence now that when the universe was about 7% of its
link |
01:58:23.280
present age, infant, already back then, you had black holes of a billion times the mass of the
link |
01:58:30.000
sun, which is quite remarkable. It's like finding giant babies in a nursery. How can these black
link |
01:58:39.120
holes grow so fast? Less than a billion years after the Big Bang, you already have a billion times
link |
01:58:44.400
the mass of the sun in these black holes. And the answer is presumably there are very quick
link |
01:58:51.040
processes that build them up. They build quickly. Very quickly. And so we see those black holes.
link |
01:58:59.760
And that was found in the mid 1960s, but in 2015, exactly 100 years after Einstein came up with his
link |
01:59:09.840
theory of gravity, the LIGO observatory detected gravitational waves. And these are just ripples
link |
01:59:17.360
in space and time. So according to Einstein's theory, the innovation, the ingenuity of Einstein's
link |
01:59:22.560
theory of gravity that was formulated in November 1915 was to say that space and time
link |
01:59:30.800
are not rigid. You know, they are, they respond to matter. So for example, if you have two black
link |
01:59:39.520
holes and they collide, it's just like a stone being thrown into the surface of a pond. They
link |
01:59:47.680
generate waves, disturbances in space and time that propagate out at the speed of light. These
link |
01:59:53.840
are gravitational waves. They create a space time storm around them. And then the waves go
link |
02:00:00.320
all the way through the universe and reach us. And if you have a sensitive enough detector like
link |
02:00:06.080
LIGO, you can detect these waves. And so it was not just the message that we received for the
link |
02:00:12.160
first time, gravitational waves, but it was the messenger. So there are two aspects to it. One
link |
02:00:17.680
is the messenger, which is gravitational wave. For the first time, we're detected directly.
link |
02:00:21.760
And the second was the message, which was a collision of two black holes, because we could
link |
02:00:26.800
see the pattern of the ripples in space and time. And it was fully consistent with the prediction
link |
02:00:33.600
that Schwartz had made for how a black, the space time around the black hole is, because when two
link |
02:00:38.640
black holes collide, you can sort of map from the message that you get, you can reconstruct what
link |
02:00:46.000
really happened. And it's fully consistent. And in 2017 and 2020, there's two Nobel prizes.
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02:00:54.720
That's right. That had to do with the black holes. Can you maybe describe in the same
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02:01:01.760
massive way that you've already been doing what those Nobel prizes were given for?
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02:01:06.720
Yeah. So the 2017 was given for the LIGO collaboration for discovering
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02:01:12.000
gravitation waves from collisions of black holes. And the 2020 Nobel prize in physics
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02:01:20.480
was given for two things. One was theoretical work that was done by Roger Penrose in the 1960s,
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02:01:29.440
demonstrating that black holes are inevitable when stars collapse. And it was mostly mathematical
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02:01:38.320
work. And actually, Stephen Hawking also contributed significantly to that frontier. And
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02:01:45.280
unfortunately, he is not alive, so he could not be honored. So Penrose received it on his own.
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02:01:51.600
And then two other astronomers received it as well, Andrea Ghez and Reinhard Genzel,
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02:01:58.560
and they provided conclusive evidence that there is a black hole at the center of the Milky Way
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02:02:03.840
galaxy that weighs about four million times the mass of the sun. And they found the evidence from
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02:02:11.280
the motion of stars very close to the black hole, just like we see the planets moving around the
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02:02:16.640
planets moving around the sun. There are stars close to the center of the galaxy, and they are
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02:02:21.920
orbiting at very high speeds of other thousands of kilometers per second, or thousands of miles
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02:02:27.680
per second. Think about it, which can only be induced at those distances if there is a four
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02:02:38.240
million solar mass object that is extremely compact. And the only thing that is compatible
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02:02:47.040
with the constraints is a black hole. And they actually made a movie of the motion of these
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02:02:54.640
stars around the center. One of them moves around the center over a decade, over timescales that
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02:03:01.120
we can monitor. And it was a breakthrough in a way. So combining LIGO with the detection of
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02:03:11.280
a black hole at the center of the Milky Way and in many other galaxies like quasars,
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02:03:17.520
now I would say black hole research is vogue. It's very much in fashion. We saw it back in
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02:03:26.320
2016 when we established the black hole initiative. You saw that there is this excitement about in
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02:03:36.000
breakthroughs and discoveries around black holes, which are probably one of the most fascinating
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02:03:41.600
objects in the universe. It's up there. They're both terrifying and beautiful, and they capture
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02:03:49.200
the entirety of the physics that we know about this universe. I should say the question is,
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02:03:53.440
where is the nearest black hole? Can we visit it? I wrote a paper with my undergraduate student,
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02:04:00.880
Amir Siraj, suggesting that perhaps if there is one in the solar system, we can detect it.
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02:04:09.920
I don't know if you heard, but there is a claim that maybe there is a Planet 9 in the solar system
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02:04:17.840
because we see some anomalies at the outer parts of the solar system. So some people suggested
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02:04:22.480
maybe there is a planet out there that was not yet detected. So people searched for it,
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02:04:28.080
didn't find it. It weighs roughly five times the mass of the Earth. And we said, okay, maybe you
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02:04:33.760
can't find it because it's a black hole that was formed early in the universe.
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02:04:38.000
So where do you stand on that?
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02:04:40.640
It could be that the dark matter is made of black holes of this mass. We don't know what
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02:04:44.560
the dark matter is made of. It could be black holes. So we said, but there is an experimental
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02:04:50.240
way to test it. And the way to do it is because there is the ore cloud of icy rocks in the outer
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02:04:59.680
solar system. And if you imagine a black hole there, every now and then, a rock will pass
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02:05:06.080
close enough to the black hole to be disrupted by the very strong gravity close to the black hole.
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02:05:12.240
And that would produce a flare that you can observe. And we calculated how frequently these
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02:05:17.280
flares should occur. And with LSSD on the Vera Rubin Observatory, we found that you can actually
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02:05:23.120
test this hypothesis. And if you don't see flares, then you can put limits on the existence of a
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02:05:29.360
black hole in the solar system. It would be extremely exciting if there was a black hole,
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02:05:33.920
if Planet Nine was a black hole, because we could visit it and we can examine it.
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02:05:40.560
And it will not be a matter of an object that is very removed from us.
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02:05:45.360
Another thing I should say is, it's possible that the black hole affected life on Earth.
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02:05:51.680
The black hole at the center of the Milky Way. How? You know, that black hole right now is
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02:05:58.080
dormant. It's very faint. But we know that it flares. When a star like the Sun comes close to
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02:06:05.760
it, the star will be spaghettified, basically become a stream of gas, like a spaghetti. And then
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02:06:13.360
the gas would fall into the black hole and there would be a flare. And this process happens once
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02:06:18.720
every 10,000 years or so. So we expect that, you know, these flares to occur every 10,000 years.
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02:06:24.720
But we also see evidence for the possibility that gas clouds were disrupted by the black hole,
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02:06:31.440
because the stars that are close to the black hole are residing in a single or two planes.
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02:06:37.760
And the only way you can get that is if they formed out of a disk of gas, just like the
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02:06:42.160
planets in the solar system formed. So there is evidence that gas fell into the black hole and
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02:06:48.720
powered possibly a flare. And these flares produce X rays and ultraviolet radiation that could damage
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02:06:57.200
life if the Earth was close enough to the center of the galaxy. Where we are right now, it's not
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02:07:05.280
very risky for us. But there is a theoretical argument that says the solar system, the Sun,
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02:07:13.840
was closer to the galactic center early on, and then it migrated outwards. So maybe in the early
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02:07:22.800
stage of the solar system, the conditions were affected, shaped by these flares
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02:07:30.000
of the black hole at the center of the galaxy. And that's why for the first two billion years,
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02:07:33.840
there wasn't any oxygen in the atmosphere, who knows. But it's just interesting to think that
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02:07:40.640
from a theoretical concept that Einstein resisted in 1939, it may well be that black holes have
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02:07:48.800
influence on our life. And that it's just like discovering that some stranger affected your
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02:07:57.680
family and in a way, your life. And if that happens to be the case, a second Nobel Prize
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02:08:06.560
should be given not for just the discovery of this black hole at the center of the galaxy,
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02:08:11.920
but perhaps for the Nobel Prize in chemistry for the effect that it had.
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02:08:15.840
But the effect for the interplay that resulted in some kind of,
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02:08:19.840
yeah, the chemical effect, biology, I mean, all those kinds of things in terms of
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02:08:27.360
the emergence of life and the creation of a habitable environment. That's so fascinating.
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02:08:33.360
And of course, like you said, dark matter, like black holes have some...
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02:08:36.800
They could be the dark matter in principle, yes. We don't know what the dark matter is at the moment.
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02:08:43.200
Does it make you sad? So you've had an interaction and perhaps a bit of a friendship
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with Stephen Hawking. Does it make you sad that he didn't win the Nobel?
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02:08:52.000
Well, all together, I don't assign great importance to prizes because...
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02:08:58.000
As you said.
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02:08:58.480
You know, Jean Paul Satter, who I admire as a teenager because I was interested in philosophy.
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02:09:04.640
When I grew up on a farm in Israel, I used to collect eggs every afternoon and I would drive
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02:09:10.160
the tractor to the hills of our village and just think about philosophy, read philosophy books.
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02:09:15.600
And Jean Paul Satter was one of my favorites. And he was honored with the Nobel Prize in literature.
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02:09:21.760
He was a philosopher primarily, existentialist. And he said, the hell with it, why should I give
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02:09:29.280
special attention to this committee of people that get their self importance from awarding me
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02:09:36.160
the prize? Why does that merit my attention? So he gave up on the Nobel Prize.
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02:09:43.760
And, you know, there are two benefits to that. One, that you don't, you're not working your
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02:09:51.040
entire life in the direction that would satisfy the will of other people. You know, you work
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02:09:56.080
independently, you're not after these honors. Just for the same reason that if you're not
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02:10:02.960
living your life from making a profit or money, you can live a more fulfilling life because you're
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02:10:08.720
not being swayed by the wind, you know, of how to make money and so forth. The second aspect of
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02:10:15.520
it is, you know, that very often, you know, these prizes, they, they distort the way we do science
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02:10:26.720
because instead of people willing to take risks, and instead of having announcements only after
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02:10:35.680
a group of people converges with a definite result, you know, the natural progression of
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02:10:43.520
science is based on trial and error, you know, so reporting some results and perhaps they're wrong,
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02:10:48.880
but then other people find perhaps better evidence and then you figure out what's going on. And
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02:10:53.760
that's the natural way that science is, you know, it's a learning experience. So if you give the
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02:10:58.720
public an image by which scientists are always right, you know, and, and, and, you know, some of
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02:11:04.240
my colleagues say we must do that because otherwise the public will never believe us that global
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02:11:08.640
warming is really taking place. But that's not true because the public will really believe you
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02:11:13.600
if you show the evidence. So the point is you should be sincere when the evidence is not
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02:11:18.560
absolutely clear or whether there are disputes about the interpretation of the evidence, we
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02:11:22.160
should show ourselves, you know, the king is naked. Okay. There is no point in pretending that the
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02:11:28.320
king is dressed, saying that scientists are always right. Scientists are wrong frequently.
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02:11:35.040
And the only way to make progress is by evidence, giving us the support that we need to make
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02:11:42.000
airtight arguments. So when you say global warming is taking place, if the evidence is
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02:11:47.920
fully supportive, there are no holes in the argument, then people will be convinced because
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02:11:53.680
you're not trying to fool them. When the evidence was not complete, you also show them that the
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02:11:57.600
evidence is not complete. And when there's holes, you show that there's holes and here's the
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02:12:01.360
methodology we're using to try to close those holes. Exactly. Let's be sincere. Why pretend?
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02:12:05.840
So if there were no, in a world where there were, there were no prizes, no honours,
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02:12:10.640
we would act like kids, as I said before, we would really be focusing on the ball and not
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02:12:16.480
on the audience. Yeah, the prizes get in the way and it's, it's so powerful. Do you think
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02:12:22.640
in some sense the few people that have turned down the prize made a much more powerful statement?
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02:12:28.560
I don't know if you're familiar in the space of mathematics with the Fields Medal
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02:12:33.360
and a good girl at Perlman who turned down the prize. So he, I've committed, one of the reasons
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02:12:40.640
I started this podcast is I'm going to definitely talk to Putin, I'm definitely talking to Perlman
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02:12:46.000
and people keep telling me it's impossible. I love hearing that because I'll talk to both.
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02:12:52.240
Anyway, but do you have a sense of why he turned down the prize and is that a powerful statement
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02:13:02.640
to you? Well, what I read is that you're talking about the mathematician. The mathematician turned
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02:13:07.760
down the prize. What I read is that he was disappointed by the response of the community,
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02:13:12.480
the mainstream community, the mathematicians, to his earlier work where they dismissed it,
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02:13:19.360
they didn't attend to the details and didn't treat him with proper respect because he was not
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02:13:25.920
considered one of them. And I think that speaks volumes about the current scientific culture
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02:13:34.000
which is based on groupthink and on social interaction rather than on the merit of the
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02:13:43.440
argument and on the evidence in the context of physics. So in mathematics there is no empirical
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02:13:48.480
basis, you're exploring ideas that are logically consistent, but nevertheless there is this
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02:13:56.080
groupthink. And I think he was so frustrated with his past experience that he didn't even bother to
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02:14:03.040
publish his papers, he just posted them on the archive and in a way saying, you know,
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02:14:09.680
I know what the answer is, go look at it. And then again, in the long arc of history,
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02:14:16.000
his work on archive will be remembered and all the prizes, most of the prizes will be forgotten.
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02:14:22.640
That's what people don't kind of think about. When you look at Roger Penrose, for example,
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02:14:28.800
is another fascinating figure. You know, it's possible, and forgive me if I'm sure I'm ignorant,
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02:14:35.280
but he's also did some work on consciousness. He's been one of the only people who spoke about
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02:14:40.800
consciousness, which for the longest time is still arguably outside of the realm of the sciences.
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02:14:48.720
It's still seen as a taboo subject. And he was brave enough to explore it from a physics
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02:14:57.440
perspective, from just a philosophical perspective, but with the rigor, like proposing different
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02:15:02.880
kind of hypotheses of how consciousness might be able to emerge in the brain. And it's possible
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02:15:08.160
that that is the thing he's remembered for, if you look hundred years from now, right? As opposed
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02:15:13.280
to the work in the black holes, which fits into the kind of, like the fits into what the current
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02:15:22.000
scientific community allows to be the space of what is and isn't science.
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02:15:28.800
Yeah, it's really interesting to look at people that are innovators, where in some phases of their
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02:15:34.720
career, their ideas fit into the social structure that is around them, but in other phases,
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02:15:42.400
it doesn't. And when you look at them, they just operated the same way throughout.
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02:15:48.000
And it says more about their environment than about them.
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02:15:52.720
Well, yeah, I don't know if you know who Max Tagmark is.
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02:15:55.280
Yeah, of course. He's a friend of mine.
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02:15:58.000
I just recently talked to him again. And he, I mean, he was a little bit more explicit about
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02:16:02.880
saying, you know, being aware, which is something I also recommend is like being aware where the
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02:16:07.200
scientific community stands and doing enough to get, like move along into your career in your
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02:16:12.480
career. And yeah, it's the necessary evil, I suppose. If you are one of those out of the box
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02:16:17.840
thinkers that just naturally have this childlike curiosity, which Max definitely is one of them,
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02:16:23.600
is sometimes you have to do some stuff that fits in, you publish and you get 10 years and all those
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02:16:28.080
kinds of things. But the tenure is a great privilege because it allows you to, in principle,
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02:16:32.480
explore things that are not accepted by others. And unfortunately, it's not being taken advantage
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02:16:40.000
of by most people. And it's a waste of a very precious resource.
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02:16:45.200
Yeah, absolutely. The space that you kind of touched on, that's full of theories and is perhaps
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02:16:53.520
detached from appreciation of empirical evidence or longing for empirical evidence or grounding
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02:17:01.440
in empirical evidence is the theoretical physics community and the interest in unifying the laws
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02:17:08.480
of physics and with the theory of everything. I'm not sure from which direction to approach
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02:17:16.480
this question, but how far away are we from arriving at a theory of everything, do you think?
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02:17:23.200
And how important is it to try to arrive at it at this kind of goal of this beautiful,
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02:17:33.280
simple theory that unlocks the very fundamental basis of our nature as we know it? And what
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02:17:46.160
are the kinds of approaches we need to take to get there?
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02:17:50.160
Yeah, so in physics, the biggest challenge is to unify quantum mechanics with gravity.
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02:17:56.240
And I believe that once we have experimental evidence for how this happens in nature,
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02:18:04.320
in systems that have quantum mechanical effects, but also gravity is important,
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02:18:09.920
then the theory will fall into our lap. But the mistake that is made by the community right
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02:18:17.280
now is to come up with the right theory from scratch. And Einstein gave the illusion that you
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02:18:26.000
can just sit in your office and understand nature when he came up with his general theory
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02:18:32.560
of relativity. But first of all, perhaps he was lucky, but it's not a rule. The rule is that you
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02:18:40.480
need evidence to guide you, especially when dealing with quantum mechanics, which is really
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02:18:44.320
not intuitive. And so there are two places where the two theories meet. One is black holes.
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02:18:54.320
And there is a puzzle there. It's called the information paradox. In principle, you can throw
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02:18:59.920
the encyclopedia Britannica into a black hole. It's a lot of information. And then it will be
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02:19:06.160
gone because a black hole carries only three properties or qualities, the mass, the charge,
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02:19:15.040
and the spin, according to Einstein. But then when Hawking tried to bring in quantum mechanics
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02:19:22.160
to the game, he realized that black holes have a temperature and they radiate. This is called
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02:19:28.400
Hawking radiation. And it was sort of anticipated by Jacob Bekenstein before him. And Hawking wanted
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02:19:38.880
to prove Bekenstein wrong and then figure this out. And so what it means is black holes eventually
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02:19:44.800
evaporate. And they evaporate into radiation that doesn't carry this information, according to
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02:19:50.880
Hawking's calculation. And then the question is, according to quantum mechanics, information must
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02:19:55.920
be preserved. So where did the information go if a black hole is gone? And where is the information
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02:20:04.560
that was encoded in the encyclopedia when it went into the black hole? And to that question,
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02:20:10.960
we don't have an answer yet. It's one of those puzzles about black holes. And it touches on the
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02:20:15.920
interplay between quantum mechanics and gravity. Another important question is, what happened
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02:20:22.320
at the beginning of the universe? What happened before the Big Bang? And by the way, on that,
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02:20:28.400
I should say, you know, there are some conjectures. In principle, if we figure it out, if we have a
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02:20:36.320
theory of quantum gravity, it's possible to imagine that we will figure out how to create a universe
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02:20:42.640
in the laboratory. By irritating the vacuum, you might create a baby universe. And if we do that,
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02:20:49.920
it will offer a solution to what happened before the Big Bang. Perhaps the Big Bang emerged from
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02:20:55.040
the laboratory of another civilization. So it's like, baby universes are being born out of laboratories.
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02:21:02.640
And inside the baby universe, you have a civilization that brings to existence a new baby
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02:21:07.440
universe, just like humans, right? We have babies and they make babies. So in principle,
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02:21:12.560
that would solve the problem of why there was a Big Bang, and also what happened before the
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02:21:19.040
Big Bang. So we came, our umbilical cord is connected to a laboratory of a civilization that
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02:21:25.840
produced our universe once it figured out quantum gravity. It's baby Big Bangs all the way down.
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02:21:32.960
It's just Big Bangs all the way down. So if we collect data about how the universe started,
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02:21:38.000
we could potentially test theories, or it can educate us about how to unify quantum mechanics
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02:21:44.240
and gravity. If we could, if we get any information about what happens near the singularity of a
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02:21:49.120
black hole, you know, if we, if we get a sense of, you know, somehow we learn what happens at the
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02:21:56.400
same, that would educate. So there are places where we can search for evidence, but it's very
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02:22:02.560
challenging, I should say. And my point is, you know, the string theories, they decided that they
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02:22:08.000
know how to approach the problem, but they don't have a single theory. There is a multitude of
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02:22:14.960
theories, and it's not tightly constrained, and they cannot make predictions about black holes,
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02:22:20.560
or about the beginning of the universe. So, so at the moment, I say we're at a loss. And the way I
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02:22:26.000
feel about this concept of the theory of everything, we should wait until we get enough evidence to
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02:22:32.320
guide us. And until then, you know, there are many important problems that we can address,
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02:22:36.320
you know, why, why bang our head against the wall on a problem for which we have no guidance?
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02:22:43.280
Right. We don't have a good dance partner in terms of evidence. There's not, I mean, it'd be
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02:22:47.840
interesting, just like you said, I mean, the lab is one place to create universes or black holes,
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02:22:55.440
but it'd be fascinating if there is indeed a black hole in our solar system that you can
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02:23:00.080
interact with. So the problem with the origin of the universe is all you can do is collect data
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02:23:05.040
about it, right? You can't interact with it. Well, you can, for example, detect gravitational waves
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02:23:10.400
that emerged from that. And, you know, there is an effort to do that. And that could potentially
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02:23:15.680
tell us something. But yeah, it's a challenge. And that's why we're stuck. So I should say,
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02:23:23.840
despite what physicists portray that, you know, we live through an exceptional growth in our
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02:23:29.760
understanding of the universe, we're actually pretty much stuck, I would say, because we don't
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02:23:34.640
know the nature of the dark matter, most of the matter in the universe. We don't know what it is.
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02:23:39.920
And we don't know how the universe started. We don't know what happens in the interior of a black
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02:23:45.040
hole. Because you've thought quite a bit about dark matter as well. Do you have any kind of
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02:23:49.600
hypothesis, interesting hypothesis? We already mentioned a few about what is dark matter and
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02:23:55.120
what are the possible paths that we could take to unlock the mystery of dark? What is dark matter?
link |
02:24:02.400
Yeah, so what we need is some anomalies that would hint what the nature of the dark matter is,
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02:24:08.160
or to detect it in the laboratory. There are lots of laboratory experiments
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02:24:11.760
searching, but it's like searching for a needle in a haystack, because there are so many possibilities
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02:24:16.160
for the type of particle that it may be. But maybe at some point, you know, we'll find either a
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02:24:22.720
particle or black holes as dark matter or something else. But at the moment...
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02:24:27.600
Can you also maybe start to interrupt, to comment about what is dark matter? Like what? It's just
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02:24:32.480
the name we're assigned to. What? So most of the community believes that it's a particle
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02:24:39.440
that we haven't yet detected. It doesn't interact with light, so it's dark. But the question is,
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02:24:45.680
what does it interact with and how can we find it? And for many years, physicists were guided by
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02:24:52.480
the idea that it's some extension of the standard model of particle physics. But then they said,
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02:24:58.400
oh, we will find some clues from the Large Hadron Collider about its nature. Or maybe it's related
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02:25:04.560
to supersymmetry, which is a new symmetry that we haven't found any evidence for. In both cases,
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02:25:09.600
the Large Hadron Collider did not give us any clues. And other people search for specific types
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02:25:15.760
of particles in the laboratory and didn't find any. A couple of years ago, actually,
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02:25:21.120
around the time that I worked on Oumuamua, I also worked on the possibility that the dark
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02:25:27.760
matter particles may have a small electric charge, which is a speculation. But nobody complained about
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02:25:34.800
it. And it was published. And I regarded more of a speculation than the artificial origin of
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02:25:42.240
Oumuamua. And to me, as far as I'm concerned, I applied the same scientific tools in both cases.
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02:25:49.840
There is an anomaly that led me to that discussion, which has to do with the hydrogen being called in
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02:25:56.160
the early universe more than we expected. So we suggested maybe the dark matter particles have
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02:26:00.480
some small charge. But you deal with anomalies by exploring possibilities. That's the only way
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02:26:06.720
to do it. And then collecting more data to check those. And searching for technological signatures
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02:26:15.440
is the same as any other part of our scientific endeavor. We make hypotheses and we collect data,
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02:26:24.960
and I don't see any reason for having a taboo on this subject.
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02:26:28.720
And your childlike, open minded excitement and approach to science, I think to anyone listening
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02:26:35.760
to this is truly inspiring. I mean, the question I think is useful to ask is by way of advice
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02:26:42.320
for young people. A lot of young people listen to this, whether from all over the world,
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02:26:47.600
and teenagers, undergraduate students, even graduate students, even be like even young faculty,
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02:26:56.080
even older faculty, they're all young and hard. Like there's many young and hard. Do you have
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advice for bullets focused on the traditionally defined sort of young folks like undergraduate?
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02:27:05.840
Do you have advice to give to young people like that today about life, maybe in general,
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02:27:12.720
maybe a life of curiosity in the sciences? Definitely. Well, first I should confess that
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I enjoy working with young people much more than with senior people. And the reason is they don't
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02:27:24.560
carry a baggage of prejudice. They're not so self centered. They're open to exploration.
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02:27:30.960
My advice, I mean, one of the lessons that took me a while to learn, and I should say I lost
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02:27:38.480
important opportunities as a result of that. So that I would regard it as a mistake on my behalf
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02:27:44.080
was to believe experts. So quote unquote. So on a number of occasions, I would come up with an
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02:27:52.480
original idea, and then suggest it to an expert, someone that works in the same field for a while.
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02:27:59.040
And the expert would dismiss it most of the time because it's new and was not explored,
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02:28:06.480
not because of the merit. And then what happened to me several times is that someone else would
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02:28:12.880
listen to the conversation or would hear me suggesting it. And I would give up because the
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02:28:18.720
expert said no. And then that someone else, you know, would develop it so that it becomes the
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02:28:25.600
so that it becomes the hottest thing in this field. And it happened, you know, once it happened to me
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02:28:30.400
multiple times, I then realized the hell with the experts, you know, like, they don't know what
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02:28:36.160
they're talking. They're just repeating them. Yes, they don't think creatively, they are being
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02:28:41.200
threatened by innovation. Okay. And it's the natural reaction of someone that cares about
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02:28:48.800
their ego more than about the matter that we are discussing. And so I said, I would not,
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02:28:54.880
I don't care how many likes I have on Twitter. I don't care whether the experts say one thing
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02:28:59.600
or another, I will basically exercise my judgment and do the best I can, you know,
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02:29:04.640
turns out that I'm wrong. I made a mistake, you know, that's part of the of the scientific endeavor,
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02:29:10.880
you know, and it took me a while to recognize that and it was a lot of wasted opportunities. So
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02:29:16.560
to the young people, I would recommend, don't listen to experts, carve your own path. Now,
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02:29:24.000
of course, you will be wrong. You should learn from experience, just like kids do. But do it yourself.
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02:29:32.960
Your father died in 2017. Your mother died in 2019. Do you miss them? Very much so.
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02:29:45.360
Is there a memory that fond memory that stands out or maybe
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02:29:51.200
be whatever you learned from them? From my mother, I mean, she was very much my inspiration for
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02:29:59.600
pursuing intellectual work because she studied at the university. And then because of the
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02:30:07.760
Second World War, after the Second World War, she was born in Bulgaria, they immigrated to
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02:30:13.680
Israel and and she left university to work on a farm. And later in life, when all the kids left
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02:30:24.240
home, she went back to the university and finished the PhD. But she planted in me the intellectual
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02:30:30.640
curiosity and valuing learning as or acquiring knowledge as a very important element in life.
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02:30:40.960
And and my love with philosophy came from attending classes that she took at the university.
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02:30:50.080
When I was a teenager, I was fortunate to go to some of these and they inspired me later on. And
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02:30:58.000
I'm very different than my colleagues, as you can tell, because my upbringing was quite different.
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02:31:03.920
And the only reason I'm doing physics or astrophysics is because of circumstances. I
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02:31:08.480
at age 18, I was asked to serve in the military. And the only way for me to pursue intellectual
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02:31:17.520
work was to work on physics, because that was the closest to philosophy. And I was good at physics.
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02:31:25.920
So they admitted me to an elite program called LPO that allowed me to finish my PhD at age 24.
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02:31:32.960
And to actually propose the first international project that was funded by the Star Wars initiative
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02:31:40.400
for Ronald Reagan. And that brought me brought me to the US to visit Washington DC, where we were
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02:31:46.000
funded from. And then on one of the visits, I went to the Institute for Advanced Study at Princeton
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02:31:53.680
and met John Bacal that later offered me a five year fellowship there under the condition that
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02:32:00.240
I'll switch to astrophysics, at which point, you know, I said, okay, I cannot give up on this
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02:32:05.200
opportunity. I'll do it, switch to astrophysics. It felt like a forced marriage kind of arranged
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02:32:11.440
marriage. And then I was offered the position at Harvard, because nobody wanted that.
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02:32:18.000
They first selected someone else. And that someone said, I don't want to become a junior
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02:32:23.680
faculty at the Harvard astronomy department, because the chance for being promoted are very small.
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02:32:28.480
So he took another job. And then I was second in line. They gave it to me. I didn't care much,
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02:32:32.880
because I could go back to the farm any day, you know. And after three years, I was tenured.
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02:32:38.880
And eventually, a decade later, became the chair of this department and served for nine years as
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02:32:45.760
the chair of the astronomy department at Harvard. But at that point, it became clear to me that
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02:32:51.200
I'm actually married to the love of my life, even though it was an arranged marriage. There are many
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02:32:56.320
philosophical questions in astrophysics that we can address. But I'm still very different than my
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02:33:01.760
colleagues, you know, that were focusing on technical skills in getting to this job. So my
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02:33:10.160
mother was really extremely instrumental in planting the seeds of thinking about the big picture
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02:33:17.760
in me. Then my father, he was, you know, he was working in the farm. And we didn't speak much,
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02:33:25.280
because we sort of understood each other without speaking. But what he gave me is a sense of,
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02:33:36.640
you know, that it's more important to do things than to talk about them.
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02:33:40.240
I love the, I mean, my apologies, but MIT, mind and hand, I love that there's
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02:33:49.200
that the root of philosophy that you gain from your mom and the hand that action is all that,
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02:33:56.000
ultimately, in the end, matters from your dad. That's really powerful. If we could take a small
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02:34:02.320
detour into philosophy, is there by chance any books, authors, whether philosophical or not,
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02:34:11.600
you mentioned Sartre that stand out to you that were formative in some small or big way that
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02:34:16.720
perhaps you would recommend to others, maybe when you were very young or maybe later on in life?
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02:34:22.080
Well, actually, yeah, I, you know, I read the number of existentialists that
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02:34:27.520
appealed to me because they were authentic. You know, Sartre, you know, he declined the
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02:34:34.160
Nobel Prizes we discussed, but he also was mocking people that pretend to be something
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02:34:41.040
better than they are, you know, he was living an authentic life that is sincere. And that's
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02:34:46.240
what appealed to me. And Albert Camus was another French philosopher that advocated existentialism.
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02:34:53.200
You know, that really appealed to me. That's probably my favorite existentialist Camus.
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02:34:58.400
Yeah. And he died at a young age in an accident, unfortunately. And then, you know, people like
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02:35:05.440
Nietzsche that, you know, broke conventions. And I noticed that Nietzsche is still extremely
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02:35:15.760
popular. You know, that's quite surprising. He appeals to the young people of today.
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02:35:22.160
And the people that, it's the children, it's the childlike wonder about the world. And
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02:35:26.720
he was unapologetic. You know, it's like most philosophers have a very strict
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02:35:31.360
adherence to terminology into the practices, academic philosophers. And Nietzsche was full
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02:35:36.080
of contradictions. And he just, I mean, he was just this big kid with opinions and thought deeply
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02:35:44.720
about this world. And people are really attracted to that. And surprisingly, there's not enough
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02:35:49.120
people like that throughout history of philosophy. And that's why I think this is still drawn to him.
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02:35:55.680
Yeah. To me, what stands out is his statement that the best way to corrupt the mind of young
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02:36:02.960
people is to tell them that they should agree with the common view, you know. And, you know,
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02:36:11.520
it goes back to the thread that went throughout discussion. Yes. You've kind of suggested that
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02:36:18.400
we ought to be humble about our very own existence and that our existence lasts only a short time.
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02:36:25.600
We talked about you losing your father and your mother. Do you think about your own mortality?
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02:36:33.360
Oh, yeah. Are you afraid of death? I'm not afraid. You know what Epichorus,
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02:36:37.680
actually Epichorus was a very wise person. According to Lucretius, Epichorus didn't live
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02:36:44.480
anything in writing, but he said that he's never afraid of death because as long as he's around,
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02:36:51.840
death is not around. And when death will be around, he will not be around. So he will never
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02:36:58.400
meet death. So why should you be worried about something you will never meet? You know, and
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02:37:04.160
it's an interesting philosophy of life. You know, you shouldn't be afraid of something that you
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02:37:07.840
will never encounter, right? But there's a finiteness to this experience. We live every day. I mean,
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02:37:16.720
I think of it for being honest. We live every day as if it's going to last forever. We often kind
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02:37:21.680
of don't contemplate the fact that it ends. You kind of have plans and goals and you have these
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02:37:27.360
possibilities. You have a kind of lingering thought, especially as you get older and older and older,
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02:37:32.960
that this is, especially when you lose friends, then you start to realize, you know, it doesn't.
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02:37:40.560
But I don't know if you're really cognizant of that. I mean, because...
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02:37:44.400
But you have to be careful not to be depressed by it because otherwise you lose the vitality,
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02:37:49.680
right? So I think the most important thing to draw from knowing that you are short lived
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02:37:56.160
is a sense of appreciation that you're alive. That's the first thing. But more importantly,
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02:38:02.320
a sense of modesty because how can anyone be arrogant if they kept at the same time this
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02:38:09.760
notion that they are short lived? I mean, you cannot be arrogant because anything that you
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02:38:14.080
advocate for, you know, you will not be around to do that in a hundred years. So people will
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02:38:19.920
just forget and move on, you know? And if you keep that in mind, you know, the scissors in
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02:38:26.320
ancient Rome, they had a person next to them telling them, don't forget that you are mortal.
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02:38:32.640
You know, there was a person with that duty because the scissors thought that they are all
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02:38:36.880
powerful, you know? And they had, for a good reason, someone they hired to whisper in their ear,
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02:38:47.040
don't forget that you are mortal. Well, you're somebody one of the most
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02:38:52.080
respected, famous scientists in the world sitting on a farm gazing up at the stars.
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02:38:59.440
So you seem like an appropriate person to ask the completely inappropriate question of
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02:39:04.640
what do you think is the meaning of it all? What's the meaning of life?
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02:39:08.960
That's an excellent question. And if we ever find an alien that we can converse with,
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02:39:13.840
I would like to answer this. I would like to ask for an answer to this question because...
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02:39:17.760
Would they have a different opinion, you think? Well,
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02:39:21.200
they might be wiser because they lived around for a while, but I'm afraid they will be silent.
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02:39:27.120
I'm afraid they will not have a good answer. And I think
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02:39:32.720
it's the process that you should get satisfied by, the process of learning you should enjoy.
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02:39:41.440
Okay, so it's not so much that there is a meaning. In fact, there is, as far as I can tell,
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02:39:49.280
things just exist, you know? And it's... I think it's inappropriate for us to assign
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02:39:56.960
meaning for our existence because, you know, as a civilization, we will eventually perish,
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02:40:02.640
and nothing will be, you know, just another planet on which life died, you know? And
link |
02:40:07.600
if you look at the big scheme of things, who cares? Like, who cares? And how can we assign
link |
02:40:15.680
significance to what we are doing, you know? So if you say the meaning of life is this,
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02:40:20.720
well, it will not be around in a billion years. So what, you know, it cannot be the meaning of
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02:40:26.080
life because life, you know, nothing will be around. So I think we should just enjoy the process.
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02:40:32.160
And, you know, it's like many other things in life, you enjoy good food, okay? And you can enjoy
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02:40:40.000
learning. Why? Because it makes you appreciate better the environment that you live in. And
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02:40:48.160
sometimes people think religion, for example, is in conflict with science, spirituality,
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02:40:54.480
in conflict. That's not true. If you see a watch and you look at it from the outside,
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02:41:03.120
you know, you might say, oh, that's interesting. But then if you start to open it up and learn
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02:41:07.440
about how it works, you appreciate it more. So science is the way to learn about how the world
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02:41:13.280
works. And it's not in conflict to the meaning that you assign to all of this, but it helps you
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02:41:21.120
appreciate the world better. So in fact, I would think that a religious person should promote
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02:41:27.120
science because it gives you a better appreciation of what's around you. You know, it's like, you
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02:41:32.640
know, if you buy in a grocery, buy something, you know, a bunch of fruits that are packed together,
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02:41:41.280
and you can't see from the outside exactly what kind of fruits are inside. But if you open it up
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02:41:46.080
and study, you appreciate better the merchandise that you get, right? So you pay the same amount
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02:41:50.720
of money, but at least you know what's inside. So why don't we figure out what the world is about,
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02:41:55.840
you know, what the universe contains, what is the dark matter? It will help us appreciate,
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02:42:00.240
you know, the bigger picture. And then you can assign your own flavor to what it means, you know.
link |
02:42:07.600
Ali, I think I'm truly grateful that a person like you exists at the center of the scientific
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02:42:14.800
community gives me faith and hope about this, this big journey that we call science. So
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02:42:22.880
thank you for writing the book you wrote recently. You have many other books and articles that I
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02:42:29.040
think people should definitely read. And thank you for wasting all this time with me as a truly
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02:42:34.480
an honor. Thank you so much. Was not a waste at all. And thank you for having me. I learned a lot
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02:42:38.320
from your questions and your remarks. Thank you. Thank you. Thanks for listening to this
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02:42:43.120
conversation with Avi Loeb. And thank you to our sponsors. Zero fasting app for intermittent fasting,
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02:42:49.360
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02:42:56.960
So the choice is a fasting app, fasting fuel, fast breaking, delicious meals, and a history
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you wish, click the sponsor links below to get a discount and to support this podcast. And now
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02:43:16.400
let me leave you with some words from Albert Einstein. The important thing is not to stop
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02:43:20.960
questioning. Curiosity has its own reason for existence. One cannot help but be in awe when
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02:43:27.200
he contemplates the mysteries of eternity, of life, of the marvelous structure of reality.
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02:43:33.360
It is enough if one tries merely to comprehend a little of this mystery every day.
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02:43:38.640
Thank you for listening and hope to see you next time.