back to indexAvi Loeb: Aliens, Black Holes, and the Mystery of the Oumuamua | Lex Fridman Podcast #154
link |
The following is a conversation with Avi Loeb, an astrophysicist, astronomer, and cosmologist
link |
at Harvard. He has authored over 800 papers and written eight books, including his latest,
link |
called Extra Terrestrial, The First Sign of Intelligent Life Beyond Earth. It'll be released
link |
in a couple of weeks, so go preorder it now to show support for what I think is truly an important
link |
book in that it serves as a strong example of a scientist being both rigorous and open minded
link |
about the question of intelligent alien civilizations in our universe. Quick mention of our sponsors,
link |
zero fasting app for intermittent fasting, element electrolyte drink, sunbasket meal
link |
delivery service, and pessimist archive history podcast. So the choice is a fasting app,
link |
fasting fuel, fast breaking, delicious meals, and the history podcast that has very little to do
link |
with fasting. Choose wisely, my friends, and if you wish, click the sponsor links below to get a
link |
discount and to support this podcast. As a side note, let me say a bit more about why Avi's work
link |
is so exciting to me and I think to a lot of people. In 2017, a strange interstellar object,
link |
now named a Moa Moa, it's fun to say, was detected traveling through our solar system.
link |
Based on the evidence we have, it has strange characteristics which made it not like any
link |
asteroid or comet that we've seen before. Avi was one of the only world class scientists who
link |
fearlessly suggested that we should be open minded about whether it is naturally made or in fact
link |
is an artifact of an intelligent alien civilization. In fact, he suggested that the more likely
link |
explanation given the evidence is the latter hypothesis. We also talk about a lot of fascinating
link |
mysteries in our universe including black holes, dark matter, the big bang, and close the speed
link |
of light space travel. The theme throughout is that in scientific pursuits, the weird things,
link |
the anomalies, the ideas that right now are considered taboo should not be ignored if we're
link |
to have a chance at finding the next big breakthrough, the next big paradigm shift, and also if we are
link |
to inspire the world with the power and beauty of science. If you enjoy this thing, subscribe on
link |
YouTube, review it on Apple Podcasts, follow us on Spotify, support on Patreon, or connect with me
link |
on Twitter at Lex Friedman. And now, here's my conversation with Avi Loeb. In the introduction
link |
to your new book, Extra Terrestrial, you write, this book confronts one of the universe's most
link |
profound questions. Are we alone? Over time, this question has been framed in different ways. Is
link |
life here on earth the only life in the universe? Are humans the only sentient intelligence in the
link |
vastness of space and time? A better, more precise framing of this question would be this.
link |
Throughout the expanse of space and over the lifetime of the universe, are there now or have
link |
ever been other sentient civilizations that, like ours, explored the stars and left evidence
link |
of their efforts? So let me ask, are we alone? That's an excellent question. For me, the answer is
link |
sort of clear because I start from the principle of modesty. You know, if we believe that we are
link |
alone and special and unique, that shows organs. My daughters, when they were infants, they tended
link |
to think that they are special, unique. And then they went out to the street and realized that other
link |
kids are very much like them. And then they developed a sense of a better perspective about
link |
themselves. And I think the only reason that we are still thinking that we are special is because
link |
we haven't searched well enough to find others that might even be better than us. And you know,
link |
I say that because I look at the newspaper every morning and I see that we do foolish things. We
link |
are not necessarily the most intelligent ones. And if you think about it, if you open a recipe book,
link |
you see that out of the same ingredients, you can make very different cakes, depending on how
link |
you put them together and how you heat them up. And what is the chance that by taking the soup of
link |
chemicals that existed on earth and cooking it one way to get our life, that you got the best
link |
cake possible? I mean, we are probably not the sharpest cookie in the jar. And my question is,
link |
I mean, it's pretty obvious to me that we are probably not alone because half of all the sunlight
link |
stars we know now as astronomers, half of the sunlight stars from the Kepler satellite data
link |
have a planet the size of the earth, roughly at the same distance that the earth is from the sun.
link |
And that means that they can have liquid water on their surface and the chemistry of life as we
link |
know it. So if you roll the dice billions of times just within the Milky Way galaxy,
link |
and then you have tens of billions of galaxies like it within the observable volume of the
link |
universe, it would be extremely arrogant to think that we are special. I would think that we are
link |
sort of middle of the road, typical forms of life. And that's why nobody pays attention to us.
link |
You know, if you go down the street on a sidewalk and you see an ant, you don't pay attention or
link |
a special respect to that ant, you just continue to walk. And so I think that we are sort of average,
link |
not very interesting, not exciting. So nobody cares about us. We tend to think that we are
link |
special, but that's a sign of immaturity. And we're very early on in our development.
link |
Yes, that's another thing that we have our technology only for 100 years. And it's evolving
link |
exponentially right now on a three year timescale. So imagine what would happen in 100 years,
link |
in 1000 years, in a million years or in a billion years. Now the sun is actually
link |
relatively late in the star formation history of the universe. Most of the sunlight stars formed
link |
earlier. And some of them already died, you know, became white dwarfs. And so if you imagine that
link |
a civilization like ours existed around a typical sunlight star, by now, if they survive,
link |
they could be a billion years old. And then imagine a billion year technology,
link |
it would look like magic to us, you know, an approximation to God, we wouldn't be able to
link |
understand it. And so in my view, we should be humble. And by the way, we should probably just
link |
listen and not speak. Because there is a risk, right? If if if you are inferior, there is a risk
link |
if you speak too loudly. Something bad may happen to you. You mentioned we should be humble also in
link |
the sense with the analogy to ants, that they might be better than us. So there's a kind of scale
link |
that we're talking about. And in the question, you mentioned the word sentient. So sentience, or
link |
maybe the more basic formulation of that is consciousness. Do you think do you think that
link |
this thing within us humans in terms of the typical life form of consciousness is the essential
link |
element that permeates other if if there's other alien civilizations out there that they have something
link |
like consciousness as well? Or is this I guess I'm asking, can you try to untangle the word sentient?
link |
Yeah, so that's that's a good question. I think what is most abundant, depending on how long it
link |
survives. So if you look at us as an example, we are now we do have consciousness and we do have
link |
technology. But the technologies that we are developing are also means for our own destruction,
link |
as we can tell, you know, we can change the climate if we are not careful enough,
link |
we can go into nuclear wars. So we are developing means for our own destruction through self
link |
inflicted wounds. And it might well be that creatures like us are not long lived, that the
link |
crocodiles on other planets live for billions of years, they don't destroy themselves, they live
link |
naturally. And so if you look around, the most common thing would be dumb animals that live for
link |
long times, you know, not those that have conscious. But in terms of changing the environment, I think
link |
since I mean, humans develop tools, they've developed the ability to construct technologies
link |
that would lift us from this planet that we were born in. And that's something animals without
link |
the conscious consciousness cannot really do. And, and so I, you know, in terms of
link |
looking for things that are new, that went beyond the circumstances they were born into,
link |
I would think that even if they're short lived, these are the creatures that made the biggest
link |
difference to their environment. And we can search for them, you know, even if they're short lived,
link |
and most of the civilizations are dead by now. Yeah, even if that's the case,
link |
that's sad to think about, by the way. Well, but if you look on earth, that, you know,
link |
there are lots of cultures that existed throughout time, and they're dead by now,
link |
the Mayan culture was very sophisticated, died, but we can find evidence for it and learn about it
link |
just by archaeology, digging into the ground looking. And so we can do the same thing in space,
link |
look for dead civilizations. And perhaps we can learn a lesson why they died and behave better
link |
so that we will not share the same fate. So I think, you know, there is a lesson to be learned
link |
from the sky. And by the way, I should also say, if we find the technology that we have not
link |
dreamed of, that we can import to earth, that may be a better strategy for making a fortune
link |
than going to Silicon Valley or going to Wall Street. Because you learn, you make a jump start
link |
into something of the future. So that's one way to do the leap is actually to find,
link |
to literally discover versus come up with the idea in our own limited human capacity,
link |
like a cognitive capacity. It would look like it would feel like cheating in an exam where
link |
you look over the shoulder of a student next to you. But it's not good on an exam, but it is good
link |
when you're coming up with technology that could change the fabric of human civilization. But
link |
there is, you know, in my neck of the woods of artificial intelligence, there's a lot of
link |
trajectories one can imagine of creating very powerful beings, the technology that's essentially,
link |
you know, you can call superintelligence that could achieve space exploration,
link |
all those kinds of things without consciousness, without something that to us humans looks like
link |
consciousness. And there, you know, there is a sad feeling I have that consciousness too,
link |
in terms of us being humble, is a thing we humans take too seriously, that it's we think
link |
it's special just because we have it. But it could be a thing that's actually holding us back
link |
in some kind of way. It may well be. It may well be. I should say something about AI, because I do
link |
think it offers a very important step into the future. If you look at the Old Testament, the
link |
Bible, there is this story about Noach's Ark that you might know about. Yes. Noach knew about
link |
a great flood that is about to endanger all life on earth. So he decided to build an Ark.
link |
And the Bible actually talks about specifically what the size of this Ark was, what the dimensions
link |
were. Turns out it was quite similar to Uumuamua that we will discuss in a few minutes. But
link |
at any event, he built this Ark, and he put animals on it so that they were saved from the great
link |
flood. Now, you can think about doing the same on earth, because there are risks for future
link |
catastrophes. You know, we could have the self inflicted wounds that we were talking about,
link |
like nuclear war, changing the climate, or there could be an asteroid impacting us just like the
link |
dinosaurs died. The dinosaurs didn't have size, astronomy, they couldn't have a warning system,
link |
but there was this big stone, big rock that approached them. It must have been a beautiful
link |
sight just when it was approaching, got very big and then smashed them and killed them.
link |
So you could have a catastrophe like that, or in a billion years, the sun will basically boil
link |
off all the oceans on earth. And currently, all our eggs are in one basket, but we can spread them.
link |
It's sort of like the printing press, if you think about it, the revolution that Gutenberg
link |
brought is there were very few copies of the Bible at the time, and each of them was precious
link |
because it was handwritten. But once the printing press produced multiple copies, you know, if
link |
something bad happened to one of the copies, it wasn't a catastrophe, you know, it wasn't a disaster,
link |
because you had many more copies. And so if we have copies of life here on earth elsewhere,
link |
then we avoid the risk of it being eliminated by a single point breakdown, a catastrophe.
link |
So the question is, can we build NOx spaceship that will carry life as we know it? Now, you might
link |
think we have to put elephants and whales and birds on a big spaceship. But that's not true,
link |
because all you need to know is the DNA making, the genetic making of these animals, put it on
link |
a computer system that has AI plus a 3D printer, so that this cubesat, which is rather small,
link |
can go with this information to another planet and use the raw materials there
link |
to produce synthetic life. And that would be a way of producing copies, just like the Gutenberg
link |
printing press. Yeah, and it doesn't have to be exact copies of the humans, it could just
link |
contain some basic elements of life and then have enough life on board that it could
link |
reproduce the process of evolution on another place. Right. So that also makes you sad, of course,
link |
because you confront the mortality of your own little precious consciousness and all your own
link |
memories and knowledge and all that stuff. That's right. But who cares? I mean, we are not so...
link |
I care about mine, right? And you care about yours. No, no, I actually don't. You know,
link |
if you look at the big... If you're an astronomer, one thing that you learn from the universe is
link |
to be modest, because you are not so significant. Oh, boy. I mean, think about it. All these
link |
emperors and kings that conquered the peace of land on Earth and were extremely proud. You know,
link |
you see these images of kings and emperors that usually are alpha males and they stand strong and
link |
they're very proud of themselves. But if you think about it, there are 10 to the power 20
link |
planets like the Earth in the observable volume of the universe. And this view of conquering a
link |
piece of land that even conquering all of Earth is just like an ant hugging a single grain of sand
link |
on the landscape of a huge beach. That's not very impressive. So you can't be arrogant. If you see
link |
the big picture, you have to be humble. You know, also we are short lived. You know, within 100 years,
link |
that's it, right? So what does it teach you? First, to be humble, modest. You never have
link |
significant powers relative to the big scheme of things. And second, you should appreciate every
link |
day that you live and learn about the world. Humble and still grateful. Yes, exactly. Well, let's
link |
talk about probably the most interesting object I've heard about and also the most fun to pronounce.
link |
Can you tell me the story of this object and why it may be an important event in human history?
link |
And is it possibly a piece of alien technology? Right. So this is the first object that was
link |
spotted close to Earth from outside the solar system. And it was found on October 19, 2017.
link |
And at that time, it was receding away from us. And at first, astronomers thought it must be a
link |
piece of rock, you know, just like all the asteroids and comets that we have seen from within the solar
link |
system. And it just came from another star. I should say that the actual discovery of this
link |
object was surprising to me because a decade earlier, I wrote the first paper together with
link |
Ed Turner and Amaya Morrow Martin, that tried to predict whether the same telescope that was
link |
serving the sky, pan stars from Hawaii, would find anything from interstellar space, given what we
link |
know about the solar system. So if you assume that other planetary systems have similar
link |
abundance of rocks and you just calculate how many should be ejected into interstellar space,
link |
the conclusion is no, we shouldn't find anything with pan stars. To me, I apologize,
link |
probably reviewing my stupidity, but it was surprising to me that so few interstellar objects
link |
from outside this whole system have ever been detected or none. None has been. You do maybe
link |
talk about it that there has been one or two rocks since then. Well, since then, there was one
link |
called the Borisov. It was discovered by an amateur Russian astronomer, Gennady Borisov.
link |
And that one looked like a comet. And just like a comet from within the solar system.
link |
But this is a really important point. Sorry to interrupt that. You showed that it's unlikely
link |
that a rock from another solar system would arrive to ours. Right. And so the actual detection of
link |
this one was surprising by itself, to me. Yes. But then, so at first they thought maybe it's a
link |
comet or an asteroid, but then it looked, it didn't look like anything we've seen before.
link |
Borisov did look like a comet. So people asked me afterwards and said, you know,
link |
doesn't it convince you that if Borisov looks like a comet, doesn't it convince you that
link |
Oumuamua is also natural? Yeah. And I said, you know, when I went on the first date with my wife,
link |
she looked special to me. Yes. And since then I met many women. Yes. That didn't change my
link |
opinion of my wife. You know, that's not an argument. Anyway, so why did Oumuamua look
link |
weird? Let me explain. So first of all, astronomers monitored the amount of light,
link |
sunlight that it reflects. And it was tumbling, spinning every eight hours. And as it was spinning,
link |
the brightness that we saw from that direction, we couldn't resolve it because it's tiny. It's
link |
about 100 meters, a few hundred feet, size of a football field. And we cannot, from Earth,
link |
we with existing telescopes, we cannot resolve it. The only way to actually get a photograph of it
link |
is to send the camera close to it. And that was not possible at the time that Oumuamua was
link |
discovered because it was already moving away from us faster than any rocket we can send.
link |
It's sort of like a guest that appeared for dinner. And then by the time we realized that
link |
it's weird, the guest is already out the front door into the dark street. What we would like
link |
to find is an object like it approaching us because then you can send the camera irrespective
link |
of how fast it moves. And if we were to find it in July 2017, that would have been possible
link |
because it was approaching us at that time. Actually, I was visiting Mount Haleakala
link |
in Maui, Hawaii with my family for vacation at that time in July 2017. But nobody knew
link |
at the observatory that the Oumuamua is very close. That's sad to think about that. We had
link |
the opportunity at that time to send up a camera. But don't worry. I mean, there will be more.
link |
There will be more because I operate by the Copernican principle, which says we don't leave
link |
at a special place and we don't leave at a special time. And that means if we surveyed the sky for
link |
a few years and we had sensitivity to this region between us and the sun, and we found this object
link |
with panstas, there should be many more that we will find in the future with surveys that
link |
might be even better. And actually, in three years time scale, there would be the so called LST.
link |
That's a survey of the Vera Rubin Observatory that would be much more sensitive and could
link |
potentially find an Oumuamua like object every month. Okay, so I'm just waiting for that. And
link |
the main reason for me to alert everyone to the unusual properties of Oumuamua is with the hope
link |
that next time around when we see something as unusual, we would take a photograph or we would
link |
get as much evidence as possible because science is based on evidence, not on prejudice. And we
link |
will get back to that theme. So anyway, let me let me point out some of the properties actually,
link |
yeah, the elongated nature, all those other things. So the light, the amount of light sunlight that
link |
was reflected from it was changing over eight hours by a factor of 10, meaning that the area
link |
of this object, even though we can't resolve it, the area on the sky that reflects sunlight
link |
was bigger by a factor of 10 in some phases as it was tumbling around than in other phases. So
link |
even if you take a piece of paper that is razor thin, you know, it's there is a very small likelihood
link |
that it's exactly a John. And getting a factor of 10 change in the area that you see on the sky
link |
is huge. It's much more than any. It means that the object has an unusual geometry. It's at least
link |
a factor of a few more than any of the comets or asteroids that we have seen before.
link |
You mentioned reflectivity. So it's not just the geometry, but the properties of the surface of that
link |
thing. Well, or no, if you assume the reflectivity is the same, then it's just geometry. If you
link |
assume the reflectivity may change, then it could be a combination of the area that you see and
link |
the reflectivity, because different directions may reflect differently. But the point is that
link |
it's very extreme. Yes. And it actually the best fit to the light curve that we saw was of a flat
link |
object. Unlike all the cartoons that you have seen of a cigar shape, a flat object at the 90%
link |
confidence gives a better model for the way that the light varied. And it's like flat meaning like
link |
a pancake like a pancake. Exactly. And so that's, you know, the very first unusual property. But
link |
to me, it was not unusual enough to think that it might be artificial. It was not
link |
significant enough. Then there was no cometary tail, you know, no dust, no gas around this
link |
object. And the Spitzer Space Telescope really searched very deeply for carbon based molecules.
link |
There was nothing. So it's definitely not a comet the way people expected it to be.
link |
Can you maybe briefly mention what property is a comet that you're referring to usually has?
link |
Right. So a comet is a rock that has some water ice on the surface. So you can think of it as an
link |
icy rock. Actually, comets were discovered a long time ago. But the first model that was developed
link |
for them was by Fred the Whipple, who was at Harvard. And I think the legend goes that he got the
link |
idea from walking through Harvard Square and seeing during a winter day and seeing these icy rocks,
link |
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 |
surface, when the rock gets close to the sun, the sunlight warms it up. And the ice sublimates,
link |
evaporates. Because the one thing about ice, water ice, is it doesn't become liquid if you warm it up
link |
in vacuum, you know, without an external pressure. It just goes straight into gas. And that's what
link |
you see as the tail of a comet. The only way to get liquid water is to have an atmosphere like on
link |
Earth that has an external pressure. Only then you get liquid. And that's why it's essential to have
link |
an atmosphere to a planet in order to have liquid water and the chemistry of life. So if you look
link |
at Mars, Mars lost its atmosphere. And therefore, no liquid water on the surface anymore. I mean,
link |
there may have been early and that's what the Perseverance survey, you know, the Perseverance
link |
mission will try to find out whether it had liquid water, whether there was life, perhaps,
link |
on it at the time. But at some point, it lost its atmosphere. And then the liquid water was gone.
link |
So the only reason that we can live on Earth is because of the atmosphere. But a comet is in
link |
vacuum, pretty much. And when it gets warmed up on the surface, the water becomes the water ice
link |
becomes gas. And then you see this cometary tail behind it. In addition to water, there is that
link |
there are all kinds of carbon based molecules or dust that comes off the surface. And those are
link |
detectable. Yeah, it's easy to detect. It's very prominent. You see these cometary tails that look
link |
very prominent because they reflect sunlight. And you can see them. In fact, it's sometimes
link |
difficult to see the nucleus of the comet, because it's surrounded and shrouded with. And in this
link |
case, there was no trace of anything. That's fascinating. Now, you might say, okay, it's not
link |
a, so that's what the community said. Okay, it's not a no problem. It's still a rock, you know,
link |
it's not a comet, but it's just a rock, bare rock, you know, okay, no problem. Then, and that's the
link |
thing that convinced me to write about it. And then in June 2018, you know, significantly later,
link |
there was a report that in fact, the object exhibited an excess push in addition to the
link |
force of gravity. So the sun acts on it by gravity, but then there was an extra push on
link |
this object that was figured out from the orbit that you can trace. And the question was, what is
link |
this excess push? So for comets, you get the rocket effect. When you evaporate gas, you know,
link |
just like a jet engine on an airplane, you throw a jet engine is very simple, you throw the gas back,
link |
and it pushes the airplane forward. That's all. That's how a jet. So in a case of a comet, you
link |
throw gas in the direction of the sun because it's, and then you get a push. Okay. So in the
link |
case of comets, you can get a push, but there was no cometary tail. So then people say, oh, wait a
link |
second. Is it an asteroid? No, but it behaves like a comet, but it doesn't look like a comet.
link |
So what, well, forget about it, business as usual. So that's what they mean by a non
link |
gravitation, non gravitational acceleration. So that's interesting. So like the primary force
link |
acting on something like just a rock like an asteroid would be like you can predict a trajectory
link |
based on the gravity, based on gravity. And also here there's detected movement that's not,
link |
cannot be accounted purely by the gravity of the sun. And if it was a comet, you would need
link |
about a tenth of the mass of this comet, the weight of this comet to be evaporated in order
link |
to give it. And there was no sign of that. No sign. 10% of the mass evaporating. It's huge.
link |
Think about it, a 100 meter size object losing 10% of its mass. You can't miss that.
link |
And so that's super weird. It's super weird. What is there a good expo? Is there in your mind
link |
a possible explanation for that? You know, so I operated just like Sherlock Holmes in a way.
link |
I said, okay, what are the possibilities? And the only thing I could think, so I ruled out
link |
everything else. And I said, it must be the sunlight reflected off it. Okay. So the sunlight
link |
reflects off the surface and gives it a push, just like you get a push on a sail on a boat,
link |
you know, from the wind reflecting off it. Now, in order for this to be effective,
link |
it turns out the object needs to be extremely thin. It turns out it needs to be less than a
link |
millimeter thick. Nature does not produce such things. So but we produce it because it's called
link |
the technology of a light sail. So we are for space exploration, we are exploring this technology
link |
because it has the benefit of not needing to carry the fuel with the spacecraft. So you don't have
link |
the fuel, you just have a you just have a sail and it's being pushed either by sunlight or by a
link |
laser beam or whatever. So perhaps this is a light sail. So this is actually the same technology
link |
with the with the Starshot project? Yes. So you know, people afterwards say, okay, you work on
link |
this project, you imagine, you know, no, that's a pretty good explanation, right? Obviously,
link |
my imagination is limited by what I know. So I, you know, I would not deny that,
link |
you know, working on light sails expanded my ability to imagine this possibility.
link |
But let me offer another interesting anecdote. In September this year, 2020, I mean,
link |
2020, there was another object found. And it was given the name 2020 SO by the
link |
Minor Planet Center. You know, this is an organization actually in Cambridge, Massachusetts,
link |
that gives names to objects, astronomical objects found in the solar system. And they gave it that
link |
name 2020 SO because you know, it looked like an object in the solar system. And it moved in an orbit
link |
that is similar to the orbit of the earth, but not the same exactly. And therefore, it was bound
link |
to the sun, but it also exhibited a deviation from what you expect based on gravity. So they
link |
astronomers that found it extrapolated back in time and found that in 1966, it intercepted the earth.
link |
And then they realized they went to the history books and they realized, oh, there was a mission
link |
called lunar surveyor, lunar lander, surveyor two that had a rocket booster. It was a failed mission,
link |
but there was a rocket booster that was kicked into space. And presumably, this is the rocket
link |
booster that we are seeing. Now, this rocket booster was sufficiently hollow and thin for us to
link |
recognize that it's pushed by sunlight. So here is my point. We can tell from the orbit of an
link |
object. Obviously, this object didn't have any cometary tail. It was artificially made. We know
link |
that it was made by us and it did deviate from an orbit of a rock. So just by seeing something
link |
that doesn't have cometary tail and deviates from an orbit shaped by gravity, we can tell that it's
link |
artificial. In the case of a Muammua, it couldn't have been sent by humans because it just passed
link |
near us for a few months. We know exactly what we were doing at that time. And also it was moving
link |
faster than any object that we can launch. And so obviously it came from outside the solar system.
link |
And the question is who produced it? Now, I should say that when I walk on vacation on a beach,
link |
I often see natural objects like seashells that are beautiful and I look at them. And every now
link |
and then I stumble on a plastic bottle that was artificially produced. And my point is that maybe
link |
a Muammua was a message in a bottle. And this is simply another window into searching for artifacts
link |
from other civilizations. Where do you think it could have come from? And from a scientific
link |
perspective, the narrow minded view, as we'll probably talk about throughout, is you kind of
link |
want to stick to the things that to naturally originating objects like asteroids and comets.
link |
Okay, that's the space of possible hypotheses. And then if we expand beyond that,
link |
you start to think, okay, these are artificially constructed. Like you just said, it could be by
link |
humans. It could be by by whatever that means by some kind of extraterrestrial alien civilizations.
link |
If it's the alien civilization variety, what is this object then? That's an excellent question.
link |
An excellent question. And let me lay out, I mean, we don't have enough evidence to tell. If we had a
link |
photograph, perhaps we would have more information. But there is one other peculiar fact about
link |
a Muammua. Well, other than it was very shiny, that I didn't mention, you know, we didn't detect
link |
any heat from it. And that implies that it's rather small and shiny. But the other peculiar fact is
link |
that it was it came from a very special frame of reference. So it's sort of like finding a car
link |
in a parking lot in a public parking lot that, you know, you can't really tell where it came from.
link |
So there is this frame of reference where you average over the motions of all the stars in
link |
the neighborhood of the sun. So you find the so called local standard of rest of the galaxy.
link |
And that's a frame of reference that is obtained by averaging the random motions of all the stars.
link |
And the sun is moving relative to that frame at some speed. But this object was at rest in that
link |
frame. And only one in 500 stars is so much at rest in that frame. And that's why I was saying
link |
it's like a parking lot. It was parked there and we bumped into it. So the relative speed between
link |
the solar system and this object is just because we are moving. It was sitting still. Now you ask
link |
yourself, why is it so unusual in that context? You know why? Because if it was expelled from
link |
another planetary system, most likely it will carry the speed of the host star that it came from.
link |
Because it was, you know, the most loosely bound objects are in the periphery of the planetary
link |
system. And they move very slowly relative to the star. And so they carry the when they are ripped
link |
apart from the planetary system, most of the objects will have the residual motion of the star,
link |
roughly relative to the local star. But this one was at rest in the local. Now,
link |
one thing I can think of if there is a grid of road posts, you know, like for navigation system,
link |
so that you can find your way in the local frame, then that would be one possibility.
link |
These are like little sensors. That's fascinating to think about. So there could be, I mean,
link |
not necessarily literally a grid, but just evenly in some definition of evenly spread out
link |
set of objects like these that are just out there. A lot of them. Another possibility is that these
link |
are relay stations, you know, for communication, you might think in order to communicate, you need
link |
a huge beacon, a very powerful beacon. But it's not true because even on Earth, you know, we have
link |
these relay stations. So you have a not so powerful beacon. So it can be heard only out to a limited
link |
distance. But then you relay the message. And it could be one of those. Now, after it collided
link |
with the solar system, of course, it got a kick. So it's just like a billiard ball, you know, we
link |
gave it a kick by colliding with, but most of them are not colliding with stars. And so that's one
link |
possibility. Okay. And there should be numerous lots of them if that's the case. The other possibility
link |
is that it's a probe, you know, that was sent in the direction of the habitable region around the
link |
sun to find out if there is life. Now, it takes tens of thousands of years for such a probe to
link |
traverse the solar system from the outer edge of the Earth cloud all the way to where we are.
link |
And, you know, it's a long journey. So when it started the journey from the edge of the solar
link |
system to get to us now, you know, we were rather primitive back then, you know, we still didn't
link |
have any technology. There was no reason to visit, you know, there was grass around and so forth.
link |
But, you know, maybe it is a probe. So you said 10,000 years as fast as so it takes that long
link |
tens of thousands. Yes, tens of thousands a year. Yeah. Yeah. And the other thing I should say is,
link |
you know, it could be just an outer layer of something else, like, you know, something that
link |
was ripped apart, like a surface of an instrument that was, and you can have lots of these pieces,
link |
you know, if something breaks, lots of these pieces spread out like space junk. And, you know,
link |
it could be just space junk from an alien civilization. Yes. So it's, I can tell you
link |
about space junk. Let me, what do you mean by space junk? So I think, you know, you might ask,
link |
why aren't they looking for us? One possibility is that we are not interesting, like we were talking
link |
about another possibility, you know, if there are millions of billions of years
link |
into their technological development, they created their own, their own habitat, their own cocoon,
link |
where they feel comfortable, they have everything they need. And it's risky for them to establish
link |
communication with other. So they have their own cocoon and they close off. They don't care about
link |
anything else. Now, in that case, you might say, oh, so how can we find about them if they are closed
link |
off? The answer is they still have to deposit trash, right? That's, that is something from the
link |
law of thermodynamics. There must be some production of trash. And, you know, we can still find about
link |
them just like investigative journalists going through the trash cans of celebrities in Hollywood,
link |
you know, you can learn about the private lives of those celebrities by looking at the trash.
link |
It's fascinating to think, you know, if, if we are the ants in this picture, if we, if this thing is
link |
a water bottle, or if it's like a smartphone, like where, where on the spectrum of possible
link |
objects of space, because there's a lot of interesting trash. So like, how interesting is
link |
this trash? But imagine a caveman seeing a cell phone. The caveman would think, since the caveman
link |
played with rocks all of his life, he would say, it's a rock, just like my fellow astronomers said.
link |
Yes. Right. Exactly. That's brilliantly put. Actually, as a scientist, do you hope it's a water
link |
bottle or a smartphone? Because I hope it's even more than a smartphone. I hope that it's something
link |
that is really sophisticated and funny. See, I'm the opposite. I feel like I hope it's a water bottle,
link |
because at least we have a hope with our current set of skills to understand it. Yeah, but caveman
link |
has no way of understanding the smartphone. It's like, it will be like, I feel like a caveman has
link |
more to learn from the plastic water bottle than it do from the smartphone. But suppose we figure
link |
it out, if we, if we, for example, come close to it and, and, and learn what it's made of.
link |
And I guess the smartphone is full of like thousands of different technologies that we could
link |
probably pick at. Do you have a sense of where a hypothesis of where is the cocoon that it might
link |
have come from? No, because there, okay. So first of all, you know, the solar system, the outermost
link |
edge of the solar system is called the Oort cloud. It's a cloud of icy rocks of different sizes
link |
that were left over from the formation of the solar system. And it's thought to be roughly
link |
a ball or a sphere. And it's halfway, the extent of it is roughly halfway to the nearest star.
link |
Okay. So you can imagine each planetary system basically touching the Oort clouds of those stars
link |
that are near us are touching each other. Space is full of these billiard balls that are very densely
link |
packed. And what that means is any object that you see irrespective of whether it came from the
link |
local standard. So we said that this object is special because it came from a local standard
link |
of rest. But even if it didn't, you would never be able to trace where it came from because
link |
all these Oort clouds overlap. So if you take some direction in the sky, you will cross
link |
as many stars as you have in that direction. Like there is no way to tell which Oort cloud it came
link |
from. So yes, I didn't realize how densely packed everything was from the perspective of the Oort
link |
cloud. And that's really interesting. So yeah, it could be nearby, it could be very far away.
link |
Yeah, we have no clue. You said cocoon. And you kind of paint, I think in the book, I've
link |
read a lot of your articles too on the Scientific American, which are brilliant. So I'm kind of
link |
mixing things up in my head a little bit. But there's what does that cocoon look like? What
link |
is the civilization that's able to harness the power of multiple suns, for example,
link |
look like? When you imagine possible civilizations that are a million years more advanced than us,
link |
what do you think that actually looks like? I think it's very different than we can imagine.
link |
By the way, I should start from the point that even biological life, just without technology
link |
getting into the game, could look like something we have never seen before. Take, for example,
link |
the nearest star, which is Proxima Centauri. It's four and a quarter light years away. So they will
link |
know about the results of the 2016 elections only next month in February 2021. It's very far away.
link |
But if you think about it, you know, this star is a dwarf star. And it's much cooler than it's
link |
twice as cold as the sun. And it emits mostly infrared radiation. So if there are any creatures
link |
on the planet close to it that is habitable, which is called Proxima B, there is a planet
link |
in the habitable zone, in the zone just at the right distance where in principle liquid water
link |
can be on the surface. If there are any animals there, they have infrared eyes because our eyes
link |
was designed to be sensitive to where most of the sunlight is in the visible range. But
link |
Proxima Centauri emits mostly infrared. So you know, the nearest to see each other in the nearest star
link |
system, these animals would be quite strange. They would have eyes that are detectors of
link |
infrared very different from ours. Moreover, this planet Proxima B faces the star always with the
link |
same side. So it has a permanent day side and a permanent night side. And obviously the creatures
link |
that would evolve on the permanent day side, which is much warmer, would be quite different than
link |
those on the permanent night side. Between them, there would be a permanent sunset strip. And my
link |
daughters said that that's the best opportunity for high value real estate because you will see the
link |
sunset throughout your life, right? The sun never sets on this strip. So you know, these worlds are
link |
out of our imagination. Just even the individual creatures, the sensor suite that they're operating
link |
with might be very different. Very different. So I think when we see something like that,
link |
we would be shocked not to speak about seeing technology now. So I don't even dare to imagine,
link |
you know? And I think, you know, obviously we can bury our head in the sand and say,
link |
it's never aliens, like many of my colleagues say. And it's a self fulfilling prophecy. If you
link |
never look, you will never find. If you are not ready to find wonderful things, you will never
link |
discover them. And the other thing I would like to say is reality doesn't care whether you ignore
link |
it or not. You can ignore reality, but it's still there. So we can all agree based on Twitter
link |
that aliens don't exist. That was a rock. We can all agree. And you will get a lot of likes.
link |
Have a big crowd of supporters and everyone will be happy and give each other awards and
link |
honours and so forth. But might still be an alien artifact. Who cares what humans agree on.
link |
There is a reality out there. And we have to be modest enough to recognize that we should make
link |
our statements based on evidence. Science is not about ourselves. It's not about glorifying our
link |
image. It's not about getting honours, prizes, you know, a lot of the scientific, a lot of the
link |
academic activity is geared towards creating your echo chamber where you have students,
link |
postdocs repeating your mantras so that your voice is heard loudly so that you can get more
link |
honours, prizes, recognition. That's not the purpose of science. The purpose is to figure out
link |
what nature is, right? And in the process of doing that, it's a learning experience. You make mistakes.
link |
You know, Einstein made three mistakes at the end of his career. He argued that in the 1930s,
link |
he argued that black holes don't exist, gravitational waves don't exist, and quantum
link |
mechanics doesn't have spooky action at a distance. And all three turned out to be wrong.
link |
Okay. So the point is that if you work at the frontier, then you make mistakes. It's inevitable
link |
because you can tell what is true or not. And avoiding making mistakes in order to preserve
link |
your image makes you extremely boring. Okay. You will get a prize, but you will be a boring
link |
scientist because you will keep repeating things we already know. If you want to make progress,
link |
if you want to innovate, you have to take risks and you have to look at the evidence.
link |
It's a dialogue with nature. You don't know the truth in advance. You let nature tell you, educate
link |
you. And then you realize that what you thought before is incorrect. And a lot of my colleagues
link |
prefer to be in a state where they have a monologue. You know, if you look at these people that work
link |
on string theory, they have a monologue. They know what, and in fact, their monologue is centered on
link |
anti the sitter space, which we don't live in. Now, you know, it's to me, it's just like the
link |
Olympics, you know, you define a hundred meters, and you say whoever runs this hundred meters is the
link |
best athlete, the fastest, you know, and it's completely arbitrary. You could have decided
link |
it would be 50 meters or 20 meters. Who cares? You just measure the ability of people this way.
link |
So you define anti the sitter space as a space where you do your mathematical gymnastics,
link |
and then you find who can do it the best, and you give jobs based on that, you give prizes.
link |
But as we said before, you know, nature doesn't care about, you know, the prizes that you give
link |
to each other. It cares, you know, it has its own reality, and we should figure it out. And
link |
it's not about us. The scientific activity is about figuring out nature. And sometimes we may be
link |
wrong. Our image will not be preserved. But it's that's the fun, you know, kids explore the world
link |
out of curiosity. And I always want to maintain my childhood curiosity. And I don't care about
link |
the labels that I have. In fact, having tenure is exactly the opportunity to behave like a child,
link |
because you can make mistakes. And I was asked by the Harvard Gazette, you know, the Pravda
link |
of Harvard, what is the one thing that you would like to change about the world?
link |
Yes. And I said, I would like my colleagues to behave more like kids. Yeah, that's the one thing
link |
I would like them to do. Because something bad happens to these kids when they become
link |
tenured professors, they start to worry about their ego, and about themselves more than about
link |
the purpose of science, which is, you know, curiosity driven, figuring out from evidence.
link |
Evidence is the key. So when an object shows anomalies, like, what's the problem discussing,
link |
you know, whether it's artificial or not, you know, so there was, I should tell you,
link |
there was a mainstream paper in nature, published saying, it must be natural. That's it.
link |
It's unusual, but it must be natural. Period. And then at the same time,
link |
that those means some other mainstream scientists tried to explain the properties.
link |
Yes. And they came up with interpretations like, it's a dust bunny, you know, the kind
link |
that you find in a household, a collection of dust particles pushed by sunlight,
link |
something we have never seen before. Or it's a hydrogen iceberg. It actually evaporates like a
link |
comet, but hydrogen is transparent. You don't see it. And that's why we don't see the cometary
link |
tail. Again, we have never seen something like that. In both cases, the objects would not
link |
survive the long journey. We discussed it in a paper that I wrote afterwards. But my point is,
link |
those that tried to explain the unusual properties went into great length at discussing things that
link |
we have never seen before. Okay. So even when you think about the natural origin, you have to come
link |
up with scenarios of things that were never seen before. And by the way, they look less plausible
link |
to me personally. But my point is, if we discuss things that were never seen before, right,
link |
why not discuss, why not contemplate an artificial origin? What's the problem? Why do people have
link |
this pushback? You know, I worked on dark matter. And we don't know what most of the matter in the
link |
universe is. It's called dark matter. It's just an acronym, because we have no clue. We simply
link |
don't know. So it could be all kinds of particles. And over the years, people suggested weekly
link |
interacting massive particles, axions, all kinds of particles. And experiments were made. They
link |
cost hundreds of millions of dollars. They put upper limits, constraints that ruled out many
link |
of the possibilities that were proposed as natural initially. The mainstream community regarded it
link |
as a mainstream activity to search the nature of the dark matter. And they nobody complained that
link |
it's speculative to consider weekly interacting massive particles. Now, I ask you, why is it
link |
speculative to consider extraterrestrial technologies? We have a proof that it exists here
link |
on Earth. We also know that the conditions of Earth are reproduced in billions of systems
link |
throughout the Milky Way galaxy. So what's more conservative than to say, if you arrange for
link |
similar conditions, you get the same outcome. How can you imagine this to be speculative? It's not
link |
speculative at all. And nevertheless, it's regarded the periphery. And at the same time, you have
link |
physicists, theoretical physicists working on extra dimensions, supersymmetry, super string theory,
link |
the multiverse, maybe we live in a simulation, all of these ideas that have no grounding in reality,
link |
some of which sound to me like, you know, just like what someone would say, science fiction,
link |
basically, because you have no way to test it, you know, through experiments and experiments really
link |
are key. It's not just the nuance. You say, okay, I forget about experiments, as some philosophers
link |
try to say, you know, if there is a consensus, what's the problem? The point is, it's key,
link |
then that's what Galileo, it's key to have feedback from reality. You know, you can think that you
link |
have a billion dollars or that you are more rich than, you know, Elon Musk, that's fine. You can
link |
feel very happy about it. You can talk about it with your friends and all of you will be happy
link |
and think about what you can do with the money. Then you go to an ATM machine and you make an
link |
experiment, you check how much money you have in your checking account. And if it turns out that,
link |
you know, you don't have much, you can't materialize your dreams. Okay, so you realize you have a
link |
reality check. And my point is, without experiments giving you a reality check, without the ATM
link |
machine showing you whether your ideas are bankrupt or not, without putting skin in the game. And by
link |
skin in the game, I mean, don't just talk about theoretical ideas, make them testable. If you
link |
don't make them testable, they're worthless. They're just like theology that is not testable.
link |
By the way, theology has some tests. Let me give you three examples. Yes.
link |
It turns out that my book already inspired a PhD student at Harvard in the English department
link |
to pursue a PhD in that direction. And she invited me to the PhD exam a couple of months ago.
link |
And in the exam, one of the examiners, a professor asked her, do you know why Giordano Bruno was
link |
burnt at the stake? And she said, I think it's because he was an obnoxious guy and
link |
they irritated a lot of people, which is true. But the professor said, no, it's because Giordano
link |
Bruno said that other stars are just like the sun and they could have a planet like the earth
link |
around them that could host life. And that was offensive to the church. Why was it offensive?
link |
Because there is the possibility that this life sinned. Okay. And if that life sinned
link |
on planets around other stars, it should have been saved by Christ. And then you need multiple
link |
copies of Christ. And that's unacceptable. How can you have duplicates of Christ? And so they burned
link |
the guy. It was about, okay, I'm just like loading this all in, because that's kind of brilliant.
link |
So he was actually already into this, it's not just about the stars, it's anticipating that there
link |
could be other life forms. Like why if this star, if there's other stars, why would it be special?
link |
Why would our star be special? He was making the right arguments. And he would just follow that
link |
all along to say like there should be other earth like places, there should be other life forms.
link |
And then that was offense copies of Christ. Yes. So that was offensive. So I said, I said to that,
link |
I said to that professor, I said, great, you know, I wanted to introduce some scientific tone to the
link |
discussion. And I said, this is great, because now you basically laid the foundation for an
link |
experimental test of this theology. What is the test? We now know that other stars are like the sun.
link |
And we know they have planets like the earth around them. So suppose we find life there,
link |
and we figure out that they sinned, then we ask them, did you witness Christ? And if they say no,
link |
it means that this theology is ruled out. So there is an experimental test. So this is
link |
experimental test number one. Another experimental test, you know, in the Bible, you know, in the
link |
Old Testament, Abraham was heard the voice, the voice of God to sacrifice his son, right? Only son.
link |
And that's what the story says. Now suppose Abraham, my name, by the way, had a voice memo up on his
link |
cell phone. He could have pressed this up and recorded the voice of God. And that would have
link |
been experimental evidence that God exists, right? Fortunately, he didn't. But it's an experimental
link |
test, right? There is a third example I should tell. And that is Elie Wiesel attributed this story
link |
to Martin Buber. But it's not clear whether it's true or not. At any event, the story goes that
link |
Martin Buber, you know, he was a philosopher and he said, you know, the Christians argue that Jesus,
link |
you know, the Messiah arrived already and will come back again in the future. The Jews argue
link |
the Messiah never came and will arrive in the future. So he said, why argue? Both sides agree
link |
that the Messiah will arrive in the future. When the Messiah arrives, we can ask whether he or she
link |
came before, you know, like visited us and then figure it out. And one side, so again,
link |
experimental test of a theology. So even theology, if it puts a skin in the game, you know, if it
link |
makes a prediction, could be tested, right? So why can't string theories test themselves? Or why can't,
link |
you know, even cosmic inflation, that's another model that, you know, one of the inventors from
link |
MIT, Alan Guth argues that it's not falsifiable. My point is, a theory that cannot be falsified
link |
is not helpful, because it means that you can't make progress. You cannot improve your understanding
link |
of nature. The only way for us to learn about nature is by making hypotheses that are testable,
link |
doing the experiments and learning whether we are correct or not. So be and coupled that with
link |
a curiosity and open mindedness that allows us to explore all kinds of possible hypotheses,
link |
but always the pursuit of those, the scientific rigor around those hypotheses is ultimately
link |
get evidence. Knowledge is, of what nature is, should be a dialogue with nature. Yes.
link |
Rather than a monologue. Monologue, beautifully put. Can we talk a little bit about the Drake
link |
equation, another framework from which to have this kind of discussion about possible civilizations
link |
out there? So let me ask, within the context of the Drake equation, or maybe bigger, how many
link |
alien civilizations do you think are out there? Well, it's hard to tell, because the Drake equation
link |
is again quantifying our ignorance. It's just a set of factors. The only one that we know,
link |
or actually two that we know quite well is the rate of star formation in the Milky Way Galaxy,
link |
which we measured by now, and the frequency of planets like the Earth around stars,
link |
and at the right distance to have life. But other than that, there are lots of implicit
link |
assumptions about all the other factors that will enable us to detect a signal.
link |
Now, I should say that Drake equation has a very limited validity just for signals from civilizations
link |
that are transmitting at the time that you're observing them. However, we can do much better
link |
than that. We can look for artifacts that they left behind. Even if they're dead, you can look for
link |
industrial pollution in the atmosphere of planets. Why do I bring this up? Again, to show you the
link |
conservatism of the mainstream in astronomy. By the way, I have leadership positions. I was
link |
chair of the Astronomy Department for nine years, the longest serving chair at Harvard.
link |
I'm the chair of the Board on Physics and Astronomy of the National Academies. It's a
link |
primary board. I'm director of two centers at Harvard and so forth. I do represent the community
link |
in various ways. But at the same time, I'm a little bit disappointed by the conservatism that
link |
people have. Let me give you an illustration of that. The astronomy community actually is going
link |
right now through the process of defining its goals for the next decade. There are proposals for
link |
telescopes that would cost billions of dollars and whose goal is to find evidence for oxygen
link |
in the atmosphere of planets around other stars. With the idea that this would be a marker, a
link |
signature of life. Now, the problem with that is Earth didn't have much oxygen in its atmosphere
link |
for the first two billion years. Roughly half of its life. It didn't have much oxygen, but it had
link |
life. It had microbial life. It's not clear yet as of yet what the origin is for the rise in the
link |
oxygen level after two billion years, about 2.4 billion years ago. But we know that a planet
link |
can have life without oxygen in the atmosphere because Earth did it. The second problem with this
link |
approach is that you can have oxygen from natural processes. You can break water molecules and make
link |
oxygen. So even if you find it, it will never tell you that for sure life exists there. And so even
link |
with these billions of dollars, the mainstream community will never be confident whether there
link |
is life there. Now, how can it be confident? There is actually a way. If instead of looking with
link |
the same instruments, if you look for molecules that indicate industrial pollution, for example,
link |
CFCs that are produced by refrigerating systems or industries here on Earth that they do the
link |
ozone layer, you can search for that. And I wrote a paper five years ago suggesting that.
link |
Now, what's the problem? You can just tell NASA, I want to build this telescope to search for oxygen
link |
but also for industrial pollution. Nobody would say that because it sounds like
link |
on the periphery of the field. And I ask you, why would... It's hilarious because that's exactly...
link |
That would be saying is quite brilliant because it's a really strong signal. And if life, if there's
link |
alien civilizations out there, then there are probably going to be many of them. And they're
link |
probably going to be more advanced than us. And they're probably going to have something like
link |
industrial pollution, which would be a much stronger signal than some basic gas, which could
link |
have a lot of different explanations. So like oxygen or... We could talk about signs of life
link |
on Venus and so on. But if you want a strong signal, it'll be pollution. I love how garbage is...
link |
No, but the pollution, you have to understand, we think of pollution as a problem. But on a planet
link |
that was too cold, for example, to have comfortable life on it, you can imagine terraforming it and
link |
putting a blanket of polluting gases such that it will be warmer. And that would be a positive change.
link |
So if an industrial or a technological civilization wants to terraform a planet that otherwise is
link |
too cold for them, they will do it. So what's the problem of defining it as a search goal
link |
using the same technologies? The problem is that there is a taboo. We're not supposed to discuss
link |
extraterrestrial intelligence. There is no funding for this subject, not much, very little.
link |
And young people, because of the bullying on Twitter, all the social media and elsewhere,
link |
young people with talent that are curious about these questions do not enter this field of study.
link |
And obviously, if you step on the grass, it will never grow. So if you don't give funding,
link |
obviously, the mainstream community says, look, nothing was discovered so far. Obviously,
link |
nothing would be discovered. If talented people go to other disciplines, you never search for it
link |
well enough, you will never find anything. I mean, look at gravitational wave astrophysics.
link |
It's a completely new window into the universe, pioneered by Ray Weiss at MIT. And at first,
link |
it was ridiculed. And thanks to some administrators at the National Science Foundation, it received
link |
funding despite the fact that the mainstream of the astronomy community was very resistant to it.
link |
And now it's considered a frontier. So all these people that I remember as a postdoc,
link |
a young postdoc, these people that bashed these fields, said bad things about people,
link |
said nothing will come out of it. Now they say, oh, yeah, of course. The Nobel Prize was given
link |
to the LIGO collaboration. Of course, now they are supportive of it. But my point is,
link |
if you suppress innovation early on, there are lots of missed opportunities.
link |
The discovery of exoplanets is one example. In 1952, there was an astronomer named Otto
link |
Struve. And he wrote a paper saying, why don't we search for Jupiter, like planets,
link |
close to their host star? Because if they're close enough, they would move the star back
link |
and forth and we can detect the signal. And so astronomers on time allocation committees of
link |
telescopes for 40 years argued, this is not possible, because we know why Jupiter resides
link |
so far from the sun. You cannot have Jupiter so close, because there is this region where ice
link |
forms far from the sun. And beyond that region is where Jupiter, like planets, can form. There
link |
was a theory behind it, which ended up being wrong by today's standards. But anyway,
link |
they did not give time on telescopes to search for such systems until the first system was discovered
link |
four decades after Otto Struve's paper. And the Nobel Prize was awarded to that
link |
just a couple of years ago. And you ask yourself, okay, so science still made progress. What's the
link |
problem? The problem is that this baby came out barely and there was a delay of four decades. So
link |
the progress was delayed. And I wonder how many babies were not born because of this resistance.
link |
So there must be ideas that are as good as this one that were suppressed because they were bullied
link |
because people ridiculed them that were actually good ideas. And these are missed opportunities,
link |
babies that were never born. And I'm willing to push this frontier of the search for technologies
link |
or technological signatures for the civilization. Because when I was young, I was in the military
link |
in Israel, it's obligatory to serve. And there was this saying that one of the soldiers sometimes
link |
has to put his body on the barbed wire so that others can go through. And I'm willing to suffer
link |
the pain so that younger people in the future will be able to speak freely about the possibility that
link |
some of the anomalies we find in the sky are due to technological signatures.
link |
And it's quite obvious. This is why folks in the artificial intelligence space, Elon Musk and a
link |
few others speak about this. And they look at the long arc, they say like, what, you know,
link |
this kind of, you know, you can call it like first principles thinking or you can call anything
link |
really is like, if we just zoom out from our current bickering and our current
link |
like discussions and what science is doing, look at the long arc of the trajectory we're
link |
headed at, which questions are obviously fundamental to science and that should be asked. And which
link |
is the space of hypothesis we should be exploring. And like exoplanets is a really good example of
link |
one that was like an obvious one. I recently talked to Sarah Seeger and it was very taboo when she
link |
was starting out to work on an exoplanet and that was even in the 90s. And like it's obvious
link |
should not be a taboo subject. And to me, I mean, I'm probably ignorant, but to me exoplanets seems
link |
like it's ridiculous that that would ever be a taboo subject to not fund, to not explore.
link |
That's very, but even for her, it's now taboo to say like what, you know, to look for industrial
link |
pollution, right? Right. I find that ridiculous. I'll tell you why. It's ridiculous for another
link |
reason, not because of just the scientific benefits that we might have by exploring it,
link |
but because the public cares about these questions and the public funds science. So how dare the
link |
scientists shy away from addressing these questions if they have the technology to do it? It's like
link |
saying, I don't want to look through Galileo's telescope. It's exactly the same. You have the
link |
technology to explore this question, to find evidence and you shy away from it. You might
link |
ask why do people shy away from it? And perhaps it's because of the fact that there is science
link |
fiction. I'm not a fan of science fiction because it has an element to it that violates the laws
link |
of physics in many of the books and the film. And I cannot enjoy these things when I see the
link |
laws of physics violated. But who cares that the fact that there is science fiction? I mean,
link |
if you have the scientific methodology to address the same subject, I don't care that
link |
other people spoke nonsense about this subject or said things that make no sense. Who cares?
link |
You do your scientific work just like you explore the dark matter. You explore the possibility that
link |
is an artifact. You just look for evidence and try to deduce what it means. And I have no problem
link |
with doing that. To me, it sounds like any other scientific question that we have. And given the
link |
public's interest, we have an obligation to do that. By the way, science, to me, is not an
link |
occupation of the elite. It doesn't allow me to feel superior to other humans that are unable to
link |
understand the math. To me, it's a way of life. If there is a problem in the faucet or in the pipe
link |
at home, I try to figure out what the problem is. And with a plumber, we figure it out and we
link |
look at the clues. And the same thing in science. You look at the evidence, you try to figure out
link |
what it means. It's common sense, in a way. And it shouldn't be regarded as something removed
link |
from the public. It should be a reflection of the public's interest. And I think it's actually a
link |
crime to resist the public. If the public says, I care about this. And you say, no, no, no, that's
link |
not sophisticated enough for me. I want to do intellectual gymnastics on anti the sitter
link |
space. To me, that's a crime. Yes. I 100% agree. So it's hilarious that the very, not hilarious,
link |
it's sad that people who are trained in the scientific community to have the tools to explore
link |
this world, to be children, to be the most effective at being children are the ones that
link |
resist being children the most. But there is a large number of people that embrace the childlike
link |
wonder about the world and may not necessarily have the tools to do it. That's the more general
link |
public. And so, I wonder if I could ask you and talk to you a little bit about UFO sightings,
link |
that there's people, quote unquote, believers, there's hundreds of thousands of UFO sightings.
link |
And I've consumed some of the things that people have said about it. And one thing I really like
link |
about it is how excited they are by the possibility, by it's almost like this childlike wonder about
link |
the world out there. It's not a fear, it's an excitement. Do you think, because we're talking
link |
about this possibly extraterrestrial object that visited, that flew by Earth, do you think it's
link |
possible that out of those hundreds of thousands of UFO sightings, one is an actual one or some
link |
number is an actual sighting of a nonhuman to some alien technology? And that we're not,
link |
we're too close minded to look and to see. I think to answer this question, we need better
link |
evidence. My starting point, as I said, out of modesty is that we are not particularly interesting.
link |
And therefore, I would agree, I would be hard pressed to imagine that someone wants to really
link |
spy on us. So I would think, you know, as a starting point that we don't deserve attention,
link |
and we shouldn't expect someone, but who knows. Now, the problem that I have with UFO sighting
link |
reports is that, you know, 50 years ago, there were some reports of fuzzy images, you know,
link |
saucer like things. By now, our technologies are much better, our cameras are much more sensitive.
link |
These fuzzy images should have turned into crisp, clear images of things that we are confident about.
link |
And they haven't turned that way. It's always on the borderline of believability. And because of
link |
that, I believe that it might be most likely artifacts of our instruments, or some natural
link |
phenomena that we are unable to understand. Now, of course, the reason you need, you must examine
link |
those. If, for example, pilots report about them, or the military finds evidence for them,
link |
is because it may pose a national security threat. If another country has technologies that we don't
link |
know about, and they're spying on us, we need to know about it. And therefore, we should examine
link |
everything that looks unusual. But to associate it with an alien life is a little too far for me
link |
until we have evidence that stands up to the level of scientific credence, you know, that
link |
we are 100% sure that, you know, from multiple detectors and, you know, through a scientific
link |
process. Now, again, if the scientific community shies away from these reports, we will never have
link |
that. It's like saying, I don't want to take photographs of something because I know what it
link |
is, then you will never know what it is. But I think if some scientists, if grants, let's put it
link |
this way, if funding will be given to scientists to follow on some of these reports and use scientific
link |
instruments that are capable of detecting those sightings with much better resolution, with much
link |
better information, that would be great because it will clarify the matter. You know, these are not,
link |
as you said, you know, hundreds of thousands, these are not the ones in the lifetime events.
link |
So it's possible to take scientific instrumentation and explore, go to the ocean where the,
link |
you know, someone reported that there are frequent events that are unusual and check it out, do a
link |
scientific experiment. What's the problem? Why not? Why only do experiments deep into the ocean and
link |
look at the oceanography or do other things? You know, we can do scientific investigation of these
link |
sightings and figure out what they mean. I'm very much in favor of that. But until we have the
link |
evidence, I would be doubtful as to what they actually mean. Yeah, we'll have to be humble
link |
and acknowledge that we're not that interesting. It's kind of, you're making me realize that
link |
because it's so taboo that the people that have the equipment, meaning, and we're not just talking,
link |
everybody has cameras now, but to have a large scale like sensor network that collects data,
link |
that regularly collects, just like we look at the weather, we're collecting information,
link |
and then we can then access that information when there is reports and like have it not be a taboo
link |
thing where there's like millions or billions of dollars funding this effort, that by the way,
link |
inspires millions of people. This is exactly what you're talking about. It's like the scientific
link |
community is afraid of a topic that inspires millions of people. It's absurd. But if you put
link |
blinders on your eyes, you don't see it. Yeah, right. I should say that we do have meteors that
link |
we see. These are rocks that by chance happen to collide with the Earth. And if they're small,
link |
they burn up in the atmosphere. But if they're big enough, tens of meters or more, hundreds of
link |
meters, the outer layer burns up, but then the core of the object makes it through. And this is our
link |
chance of putting our hands around an object if this meteor came from interstellar space. So
link |
one path of discovery is to search for interstellar meteors. And with the student of mine, we actually
link |
looked through the record and we thought that we found one example of a meteor that was reported
link |
that might have come from interstellar space. And another approach is, for example, to look at the
link |
moon. The moon is different from the Earth in the sense that it doesn't have an atmosphere. So objects
link |
do not burn up on their way to it. It's sort of like a museum. It collects everything that comes
link |
of rocks from out there. Yeah, deep space. Yeah. And there is no geological activity on the moon.
link |
So on Earth, every 100 million years, you know, we could have had computer terminals on Earth that
link |
could have been a civilization like ours with electronic equipment more than 100 million years
link |
ago. And it's completely lost. You cannot excavate and find it evidence for it because in archaeological
link |
digs, because the Earth is being mixed on these time scales. And everything that was on the surface
link |
more than 100 million years ago is buried deep inside the Earth right now because of geological
link |
activity. Fascinating to think about, by the way. Yeah. But on the moon, this doesn't happen. The only
link |
thing that happens on the moon is you have objects impacting the moon and they go 10 meters deep,
link |
so they produce some dust. But the moon keeps everything. It's like a museum. It keeps everything
link |
on the surface. So if we go to the moon, I would highly recommend regarding it as an archaeological
link |
site and looking for objects that are strange. Maybe it collected some trash, you know, from
link |
interstellar space. If we could just link it on the Drake equation for a little bit. We kind of
link |
talked about there's a lot of uncertainty in the parameters and the Drake equation itself is very
link |
limited. But I think the parameters are interesting in themselves, even if it's limited, because I
link |
think each one is within the reach of science, right? Did you get the evidence for it? I mean,
link |
a few I find really interesting. It's interesting to get your comment on. So the one with the most
link |
variants, I would say from my perspective, is the length that civilizations last. However you
link |
define it. In the Drake equation, it's the length of how long you're communicating, just like transmitting.
link |
Just like you said, that's a wrong way to think about it, because we can be detecting
link |
some other outputs of the civilizations, etc. But just if we just define broadly how long those
link |
civilizations last, do you have a sense of how long that might last? Like what are the great
link |
filters that might destroy civilizations that we should be thinking about? How can science
link |
give us more hints on this topic? So I, as I mentioned before, operate by the Copernican
link |
principle, meaning that we are not special. We don't live in a special place and not in a special
link |
time. And by the way, it's just modesty and encapsulated in scientific terms, right? You're
link |
saying I'm not special, you know, I find conditions here, they exist everywhere. So if you adapt the
link |
Copernican principle, you basically say our civilization transmitted radio signals for 100
link |
years, roughly. So probably it would last another 100 or a few hundred and that's it,
link |
because we don't live at a special time. So that's, you know, well, of course, if we get our act
link |
together, and we somehow start to cooperate rather than fighting each other, killing each other,
link |
you know, wasting a lot of resources on things that would destroy our planet,
link |
maybe we can lengthen that period if we get smarter. But the most natural assumption is to
link |
say that we will live into the future as much as we lived from the time that we start to develop
link |
the means for our own destruction, the technologies we have, which is quite pessimistic, I must say.
link |
So several centuries, that's what I would give, not unless we get our act, unless we become more
link |
intelligent than the newspapers report every day. Okay, point number one. Second, and by the way,
link |
this is relevant, I should say, because there was a report about perhaps a radio signal detected
link |
from Proxima Centauri. What do you make of that signal? Oh, I think it's some Australian guy with
link |
a cell phone next to the observatory or something like that, because it was the park's telescope
link |
in Australia. Okay. So it's human created noise. Yeah, which is always the worry, because actually
link |
the same observatory, the park's observatory detected a couple of years ago some signal,
link |
and then they realized that it comes back at lunch lunchtime. Yes. And they said, okay,
link |
what could it be? And then they figured out that it must be the microwave oven in the observatory,
link |
because someone was opening it before it finished, and it was creating this radio signal that they
link |
detected with a telescope every lunchtime. So just a cautionary remark. But the reason I think
link |
it's human made, without getting to the technical details, is because of this very short window by
link |
which we were transmitting radio signals out of the lifetime of the earth. You know, as I said,
link |
100 years out of four and a half billion years that the earth existed. So what's the chance that
link |
another civilization, a twin civilization of ours, is transmitting radio signals exactly at
link |
the time that we are looking with our radio telescopes, 10 to the minus seven, you know.
link |
So, and the other argument I have that is that they detected it in a very narrow band of frequencies,
link |
and that makes it, you know, it cannot be through natural processes, a very narrow band,
link |
just like some radio transmissions that we produce. But if it were to come from the habitable zone,
link |
from a transmitter on the surface of Proxima B, this is the planet that orbits Proxima Centauri,
link |
then I calculated that the frequency would drift through the Doppler effect, you know,
link |
just like when you hear a siren on the street, you know, when the car approaches you,
link |
it has a different pitch than when it goes, recedes away from you. That's the Doppler effect.
link |
And when the planet orbits the star, Proxima Centauri, you would see or detect a different
link |
frequency when the planet approaches us as compared to when it recedes. So there should be a frequency
link |
drift just because of the motion of the planet. And I calculated that it must be much bigger than
link |
observed. So it cannot just be a transmitter sitting on the planet and sending in our direction,
link |
a radio signal, unless they want to cancel the Doppler effect, but then they need to know about
link |
us, because in a different direction, it will not be canceled. Only in our direction, they can
link |
cancel it perfectly. So there is this direction of Proxima Centauri, but I have a problem imagining
link |
a transmitter on the surface of a planet in the habitable zone emitting it. But my main issue
link |
is really with a likelihood, given what we know about ourself.
link |
Right. In terms of the duration of the civilization.
link |
The Copernican principle, yeah.
link |
So nevertheless, this particular signal is likely to be a human interference, perhaps, but
link |
do you find Proxima be interesting? Or the more general question is, do you think we humans
link |
will venture out into outside our solar system and potentially colonize other habitable planets?
link |
Actually, I am involved in a project whose goal is to develop the technology that
link |
would allow us to leave the solar system and visit the nearest stars. And that is called the
link |
Starshot. In May 2015, an entrepreneur from Silicon Valley, Yuri Milner, came to my office
link |
at Harvard and said, would you be interested in leading a project that would do that in our lifetime?
link |
Because as we discussed before, to traverse those distances with existing rockets would take
link |
tens of thousands of years. And that's too long. For example, to get to Proxima Centauri with
link |
the kind of spacecrafts that we already sent, like New Horizons or Voyager 1, Voyager 2,
link |
you needed to send them when the first humans left Africa, so that they would arrive there now.
link |
And that's a long time to wait. So Yuri wanted to do it within our lifetime, 10, 20 years,
link |
meaning it has to move at a fraction of the speed of light. So can we send a spacecraft that would
link |
be moving at a fraction of the speed of light? And I said, let me look into that for six months.
link |
And with my students and postdocs, we arrived to the conclusion that the only technology that
link |
can do that is the light sail technology, where you basically produce a very powerful laser beam
link |
on Earth. So you can collect sunlight with photovoltaic cells or whatever, and then convert it into
link |
stored energy and then produce a very powerful laser beam that is 100 gigawatts
link |
and focus it on a sail in space that is roughly the size of a person, a couple of meters or a few
link |
meters, that weighs only a gram or a few grams, very thin. And through the math, you can show that
link |
you can propel such a sail, if you shine on it for a few minutes, it will traverse a distance
link |
that is five times the distance to the moon, and it will get to a fifth of the speed of light.
link |
Sounds crazy, but I've talked to a bunch of people and they're like, I know it sounds crazy,
link |
but it's actually, it will work. This is one of those, it's just beautiful. I mean, this is science.
link |
And the point is, people didn't get excited about space since the Apollo era. And it's about time,
link |
you know, for us to go into space. A couple of months ago, I was asked to participate in a debate
link |
organized by IBM and Bloomberg News, and the discussion centered on the question,
link |
is the space race between the US and China good for humanity? And all the other debaters
link |
were worried about the military threats. And I just couldn't understand what they're talking about,
link |
because military threats come from hovering above the surface of the earth, right? And
link |
we live on a two dimensional surface, we live on the surface of the earth,
link |
but space is all about the third dimension getting far from Earth. So if you go to Mars,
link |
or you go to a star, another star, there is no military threat. What are we talking about?
link |
Space is all about, you know, feeling that, you know, we are one civilization, in fact,
link |
not fighting each other, just going far and having aspirations for something that goes
link |
beyond military threats. So why would we be worried that the space race will lead?
link |
That's actually brilliant. You know, in our discourse about it, the space race is sometimes
link |
made synonymous with like the Cold War, something like that, or with wars. But really, yeah, there
link |
was a lot of ego tied up in that. I remember, I mean, it's still, still to this day, there's a
link |
lot of pride that Russians, the Soviet Union was the first to space. And there's a lot of pride in
link |
the American side that was the first on the moon. But yeah, you're exactly right. Like,
link |
there's no aggression. There's no wars. And beyond that, if you think about the global economy
link |
right now, there is a commercial interest. That's why Jeff Bezos and Elon Musk are interested about,
link |
you know, Mars and so on. There is a commercial interest which is international. It's not,
link |
it's driven by money, not by pride. And, you know, nations can sign treaties. First of all,
link |
there are lots of treaties that were signed even before the First World War and the Second World
link |
War and the World War took place. So who cares, you know, like humans, treaties do not safeguard
link |
anything, you know. But beyond that, even if nations sign treaties about space exploration,
link |
you might still find commercial entities that will find a way to get their launches. And,
link |
you know, so I think we should rethink space. It has nothing to do with national pride. Once
link |
again, nothing to do with our egos. It's about exploration. And the biggest problem, I think,
link |
to human, in human history is that, is that humans tend to think about egos and about their,
link |
their, their own personal image rather than look at the big picture. You know,
link |
we will not be around for long. We are just occupying a small space right now. Let's move
link |
out of this, you know, the way that Oscar Wilde said, I think is the best. He said,
link |
all of us are in the gutters, but some of us are looking at the stars.
link |
Yeah. And the more of us are looking at the stars, the likelier we are to, uh, to this,
link |
for this thing, for this little experiment we have going on to last, last a while, as opposed
link |
to end too quickly. I mean, it's not just about science of being humble. It's, it's about the
link |
survival of the human species is being, is being humble. To me, it's incredibly inspiring, the
link |
Starshop project of, I mean, there's something magical about being able to go to another habitable
link |
planet and take a picture even. I mean, within our lifetime, I mean, that, that, uh, with crazy
link |
technology too, which I should tell you how it was conceived. So, um, I was at the time, um,
link |
so after six months past, after the visit of Urimillah, uh, I was usually I go in December
link |
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 |
Um, just before the weekend started, they get a phone call. Uh, Yuri would like you to present
link |
your concept, um, in two weeks at his home. And I said, well, uh, thank you for letting me know,
link |
because I'm actually out of the door of the hotel to go to a goat farm in the negative,
link |
in the southern part of Israel with, because my wife wanted to have sort of, um, to go to a place
link |
that is removed from civilization, so to speak. So we went to that goat farm and, you know,
link |
I need to make the presentation and, um, there was no internet connectivity except in the office
link |
of the goat farm. So the following morning at six a.m., I sit with my back to the office of
link |
that goat farm looking at goats that were newly born and, uh, typing into my laptop the presentation,
link |
you know, the PowerPoints presentation about, you know, our ambitions for visiting the nearest
link |
star. And that was very surreal to me that, um, you know, look. Oh, like our origins in many ways,
link |
this very primitive origins and, uh, our dreams of looking out that it's brilliant. So that is
link |
incredibly inspiring to me, but it's also inspiring of putting humans onto other, um, moons or
link |
planets. I still find going to the moon really exciting. I don't know, maybe I'm just a sucker
link |
for it, but it's really exciting. And Mars, which is a new place, a new planet, another
link |
planet that might have life. I mean, there's something magical to that or some traces of
link |
previous life. You might think that humans cannot really survive. Uh, and, and there are risks
link |
by going there. But my point is, you know, we started from Africa and we got to apartment
link |
buildings in Manhattan, right? It's a very different environment from the jungles to
link |
live in an apartment building in, you know, a small cubicle. Um, and, you know, it took
link |
tens of thousands of years, but humans adapted, right? So why couldn't humans also make the leap
link |
and adapt to a habitat in space? You know that now you can build a platform that would look like
link |
an apartment building in the Bronx or somewhere, but have inside of it everything that humans need.
link |
And it just like the space station, but bigger and it will be a platform in space. And the
link |
advantage of that is if something bad happens on earth, you have that complex where humans live.
link |
And you can also move it back and forth depending on how bright the sun gets. Uh, because, you know,
link |
within, within a billion years, within a billion years, the sun would be too hot and it will boil
link |
off all the oceans on earth. So we cannot stay here for more than a billion years. That's for sure.
link |
Yes. So that's a billion years from now. Uh, I prefer like shorter term deadlines. And so
link |
in, in that's, I mean, there's a lot of threats that we're facing currently. Do you find it exciting
link |
the possibility of, uh, you know, uh, landing on Mars and starting little like, uh, building a
link |
Manhattan style apartment building on Mars and humans occupying it? Do you think from a scientific
link |
or an engineering perspective that's, uh, that's a worthy pursuit? I think it's worthy, but the
link |
real issue that is often, uh, underplayed is the risk to the human body from cosmic rays.
link |
Right. These are energetic particles and we are protected from them by the magnetic field around
link |
the earth, uh, that blocks them. But if you go to Mars where there is no such magnetic field to
link |
block them, then, um, you know, a significant fraction of the brain cells in your, your head
link |
will be damaged within a year. And the consequences of that are not clear. I mean, uh, it's quite
link |
possible that humans cannot really survive on the surface. Now it may mean that we need to dig
link |
tunnels, uh, go underground or create some protection. Uh, this is something that can be engineered.
link |
Yes. Uh, and, you know, we can start from the moon and then move to Mars. That would be a natural
link |
progression, but it's a big, uh, issue that needs to be dealt with. I don't think, you know, it's
link |
a showstopper. I think we can overcome it, but, you know, just like anything in science and technology,
link |
you have to work on it for a while, figure out solutions. And, but it's not as rosy as Elon
link |
Musk talks about. I mean, Elon Musk can obviously be optimistic. I think eventually it will boil
link |
down to figuring out, um, how to cope with this risk, the health risk. Yeah. I mean, uh, in defense
link |
of optimism, I, I find that there's at least a correlation, if not their best friends is optimism
link |
and open mindedness is, uh, it's a necessary, it's precondition to do, to do, to try crazy things.
link |
And, uh, in that sense, there, uh, the sense I have about going to Mars, if we use today's logic
link |
of what kind of benefits we'll get from that, we're never going to go. Uh, and like most decisions
link |
we'll make in life, most decisions we've made as a human species are irrational. If you just,
link |
if you look at just today, but if you look at the long arc and the possibilities that it might bring,
link |
just like humans, uh, uh, Europe and Europe and, and, and by the way, it was destroyed everybody
link |
and, uh, but it was a commercial interest that drove that, uh, for trade. And you know, it might
link |
happen again in this context. You have people like Jeff Bezos and Elon Musk that are commercially
link |
driven to go to space. Yes. But it doesn't mean that what we will ultimately find is not new worlds,
link |
you know, that have nothing, you know, much, have much more to offer than just commercial interest.
link |
And, uh, as a side effect almost, right? Yeah. Yeah. And then that's why I think, you know,
link |
we should be open minded and explore. And however, at the same time, because of the reasons you
link |
pointed out, uh, I'm not optimistic that we will survive more than a few centuries into the future,
link |
because people do not think long term. And that means that we will only survive for the short
link |
term. I don't know if you have thoughts about this, but what are the things that were you the most
link |
about, uh, from the great perspective of the universe, which is the great filters that destroys
link |
intelligence civilizations, but for our own species here, uh, like what are the things that
link |
worry you the most? Yeah. The thing that worries me the most is that people pay attention to how
link |
many likes they have on Twitter. And, uh, rather than, you know, basketball coaches tell the team
link |
players, keep your eyes on the ball, not on the audience. The problem is we keep our eyes
link |
on the audience most of the time. Let's keep our eyes on the ball. And what does that mean?
link |
First of all, in context of science, it means pay attention to the evidence. When the evidence looks
link |
strange, then we should figure it out. You know, I went to a seminar about Uumuamua at Harvard
link |
and a colleague of mine that is a mainstream conservative would never say anything that would
link |
deviate from what everyone else is thinking, said to me after the seminar, I wish this object
link |
never existed. Now, to me, I mean, I just couldn't hear that. What do you mean? Nature is whatever
link |
it is. You have to pay attention to it. You cannot say, you know, you cannot bury your head in this.
link |
I mean, you should bless nature for giving you clues about things that you haven't expected.
link |
And I think that's the biggest fault that we are looking for confirmations of things we already know
link |
so that we can maintain our pride that we already knew it and maintain our image,
link |
not make mistakes because we already knew it. Therefore, we expected the right thing. But
link |
science is a learning experience and sometimes you're wrong. And let's learn from those mistakes.
link |
And what's the problem about that? Why do we have to get prizes and why do we get to be
link |
honoured and maintain our image when the actual objective of science is learning about nature?
link |
You've talked about anomalies in this case are actually not things that are unfortunate and to
link |
be ignored are in fact gifts and should be the focus of science. Exactly, because that's the
link |
way for us to improve our understanding. If you look at quantum mechanics, nobody dreamed about it.
link |
And it was revolutionary and we still don't fully understand it. It's a pain for us to figure out.
link |
So why do you think so? I understand from the science from the perspective of that's holding
link |
our science back. Why do you ever sense that that's also something that might be a problem for us in
link |
terms of the survival of human civilization? Because when you look at society, it operates
link |
by the same principles. There is a people look for affirmation by groups and they,
link |
you know, people segregate into herds that think like them, especially these days when
link |
social media is so strong, you can find your support group. And if you don't look for evidence
link |
for what you're saying, you can say crazy things. As long as there are enough people supporting what
link |
you say, you can even have your newspapers. You can have everything to support your view.
link |
And then, you know, bad things will happen to society because we're detaching ourselves from
link |
reality. And if we detach ourselves from reality, all the destructive things that naturally can
link |
occur in the real world, whether from nuclear weapons, all the kinds of threats that we're
link |
facing, even we're living through a pandemic, the supposed, you know, a much, much worse pandemic
link |
can happen. And then we could sadly, like we did this one, politicize it in some kind of way and
link |
have bickering in the space of Twitter and politics as opposed to there's an actual thing that can
link |
destroy the human species. Exactly. So the only way for us to maintain, to stay modest and learn
link |
about what really happens is by looking for evidence. Again, I'm saying it's not about our
link |
self, you know, it's about figuring out what's around us. And if you close yourself by surrounding
link |
yourself with people that are like minded, that refuse to look at the evidence, you can do bad
link |
things. And throughout human history, that's the origin of all the bad things that happen.
link |
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 |
nuance. Now, you might say, Oh, okay, the uneducated person might operate. No, it's the
link |
scientific community operates this way. My problem is not with people that don't have an
link |
academic pedigree. It's included everywhere in society. On the topic of the discovery of
link |
evidence of alien civilizations, which is something you touch on in your book, what that
link |
idea would do to societies, to the human psyche. And in general, do you think,
link |
and you talk about the, I still have trouble pronouncing, but a more, more wager, right? What
link |
do you think is, can you explain it? And what do you think in general is the effect that such
link |
knowledge might have on human civilization? Right. So Pascal had this wager about God.
link |
And by the way, there are interesting connections between theology and the search for extraterrestrial
link |
life. You know, it's possible that, you know, we were planted on this planet by another civilization
link |
that, you know, we attribute to God powers that are that belong really to the technological
link |
civilization. But putting that aside, Pascal basically said, you know, let's, the two possibilities,
link |
either God exists or not, right? And if God exists, you know, the consequences are quite
link |
significant. And therefore, you know, we should, we should consider that possibility differently
link |
than equal weight to both possibilities. And I suggest that we do the same with Oumuamua or
link |
other technological signatures that we keep in mind the consequences. And therefore,
link |
pay more attention to that possibility. Now, some people say, extraordinary claims require
link |
extraordinary evidence. My point is that the term extraordinary is really subjective, you know.
link |
For one person, a black hole is extraordinary. For another, you know, it's just a consequence
link |
of Einstein's theory of gravity. It's nothing extraordinary. The same about the type of dark
link |
matter or anything. So we should leave the extraordinary part of that sentence. Just
link |
keep evidence. Okay, so let's be guided by evidence. And even if we have extraordinary
link |
claims, you know, let's not dismiss them because the evidence is not extraordinary enough, because
link |
if we have an image of something, and it looks really strange, and we say, oh, the image is not
link |
sufficiently sharp. Therefore, we should not even pay attention to this image or not even consider.
link |
I think that's a mistake. What we should do is say, look, there is some evidence for something
link |
unusual. Let's try and build instruments that will give us a better image. And if you just dismiss
link |
extraordinary claims, because you consider them extraordinary, you avoid discovering things that
link |
you haven't expected. And so I believe that along the history of astronomy, there are many missed
link |
opportunities. And I speak about astronomy, but I'm sure in other fields, it's also true. I mean,
link |
this is my expertise. For example, you know, the astrophysical journal, which is the main primary
link |
publication in astrophysics. If you go, you go beyond before the 1980s, there are images that
link |
were posted in the astrophysical journal of giant arcs, you know, arcs of light surrounding clusters
link |
of galaxies. And, you know, you can find it in printed versions of the astrophysical journal,
link |
people just ignore, they put the image, they see the arc, they say, who knows what it is and just
link |
ignore it. And then in the 1980s, the subject of gravitational lensing became popular. And the
link |
idea is that you can deflect light by the force of gravity. And then you can put a source behind
link |
the cluster of galaxies, and then you will get these arcs. And actually Einstein predicted it
link |
in 1940. And, you know, so these things were expected, but people just had them in the images,
link |
didn't pay attention. So I'm sure there are lost opportunities sometimes, even in existing data,
link |
you have things that are unusual and exceptional, and they're not being addressed.
link |
Yeah, you actually, I think you have the article, the data is not enough from quite a few years ago,
link |
where you talk, you know, we can go back to the 70s and 80s, but we can go also to the Mayan
link |
civilization. Right, the Mayan civilization basically believed in astrology that you can
link |
forecast the outcome of a war based on the position of the planets. And they had, you know,
link |
astronomers in their culture had the highest social status. They were priests, they were
link |
elevated. And the reason was that they helped politicians decide when to go to war, because
link |
they would tell the politicians, you know, the planets would be in this configuration,
link |
it's a better chance for you to win the war, go to war. And in retrospect, they collected wonderful
link |
data, but misinterpreted it, because we now know that the position of Venus, or Jupiter, or whatever,
link |
has nothing to do with the outcome of World War I, World War II, you know, has nothing to do. And
link |
so we can have a prejudice and collect data without actually doing the right thing with it.
link |
That's such a Pisces thing to say. I looked up what your astrological sign is.
link |
So you mentioned Einstein predicted that black holes don't exist,
link |
or just don't exist in nature. When Einstein came up with this theory of gravity in 1915,
link |
November 1915, a few months later, another physicist, Karl Schwarzschild, he was the
link |
director of the Potsdam Observatory, but he was a patriot, a German patriot. So he went into the
link |
First World War fighting for Germany. But while he was at the front, he sent a postcard to Einstein
link |
saying, you know, a few months after the theory was developed, saying, actually, I found a solution
link |
to your equations. And that was a black hole solution. And then he died a few months later.
link |
And Einstein was a pacifist, and he survived. So the lesson from this story is that if you want to
link |
work out the consequences of a theory, you better be a pacifist. But the point is that
link |
this solution was known shortly after Einstein came up with his theory. But in 1939, Einstein
link |
wrote a paper in the analysis of mathematics saying, even though the solution exists,
link |
I don't think it's realized in nature. And his argument was, if you imagine a star collapsing,
link |
stars often spin, and the spin will prevent them from making a black hole,
link |
collapsing to a point. So I mean, can you maybe one of the many things you you have worked on,
link |
you're an expert in black holes? Can you first say what are black holes? And second,
link |
how do we know that they exist? Right. So black holes are the ultimate prison.
link |
You know, you can check in, but you can never check out. Even light cannot escape from them.
link |
So there are extreme structures of space and time. And there is this so called Schwarzschild
link |
radius or the event horizon of a black hole. Once you enter into it with a spaceship,
link |
you would never be able to tweet back to your friends and tell them, by the way,
link |
I asked the students in my class, Freshman seminar at Harvard, I said,
link |
let me give you two possible journeys that you can take. I said, suppose aliens come to earth
link |
and suggest that you would board our spaceship, would you do it? And the second is suppose you
link |
could board a spaceship that will take you into a black hole, would you do it? So all of them said
link |
to the first question, yes, under one condition, that I'll be able to maintain my social media
link |
contacts and report back, share the experience with them. I couldn't personally, I have no footprint
link |
on social media. Yeah, which is as a matter of principle. Yeah, my wife asked me when we got
link |
married. And I honoured that. And I told you offline, I need to get married to such a woman.
link |
She truly is a special lady. Well, she was wise enough to recognise the risk. But it saves me time.
link |
And it also keeps me away from crowds. You know, I don't have the notion of what a lot of other
link |
people think. So I can think independently. Exactly. So I was surprised to hear that for
link |
students, it's extremely important to share experiences. Even if they go on a spaceship
link |
with aliens, they still want to brag about it rather than look around and see what's going on.
link |
This is not an option when you go to the black hole. It's exactly the point.
link |
So for the black hole, they said no, because obviously you can find your death after you
link |
get into it. You crash in the singularity. There is this singularity in the centre. So
link |
inside the event horizon, we know that all the matter collects at a point. Now, we can't really
link |
predict what happens at the singularity because Einstein's theory breaks down. And we know why
link |
it breaks down because it doesn't have quantum mechanics that talks about small distances.
link |
We don't have a theory that unifies quantum mechanics and gravity so that it will predict
link |
what happens near a singularity. And in fact, you know, I once, a couple of years ago, I had a
link |
flood in my basement. I mean, and I invited a plumber to come over and figure out. And we
link |
found that the sewer was clogged because of tree roots that got into it. And we solved the problem.
link |
But then I thought to myself, well, isn't that what happens to the singularity of a black hole?
link |
Because the question is, where does the matter go? You know, in the case of a home, I never
link |
thought about it. But the water, all the water that we use goes in through the sewer to some
link |
reservoir somewhere. And the question is, what happens inside a black hole? And one possibility
link |
is that there is an object in the middle, just like a star, you know, and everything collects
link |
there. And the object has the maximum density that we can imagine, like Planck density. It's
link |
the ultimate density that you can have, where gravity is as strong as all the other forces.
link |
So you can imagine this object, very dense object at the center that collects all the matter.
link |
Another possibility is that there is some tunnel just like the sewer. It takes the matter into
link |
another place. And we don't know the answer. But I wrote a Scientific American essay about it,
link |
admitting our ignorance. It's a fascinating question. What happens to the matter that goes
link |
into a black hole? I actually recommended to some of my colleagues that work on string theory
link |
at the closing of a conference. I'm the founding director of the Black Hole Initiative
link |
at Harvard, which brings together astronomers, physicists, philosophers, and mathematicians.
link |
And we have a conference once a year. And at the end of one of them, since I'm the director,
link |
I had to summarize and I said that I wish we could go on a field trip to a black hole nearby.
link |
And I highly recommend to my colleagues that work on string theory to enter into that black hole,
link |
because then they can test their theory when they get inside. But one of the string theories
link |
in the audience, Nimar Khani Hamid, immediately raised his voice and said, you have an ulterior
link |
motive for sending us into a black hole, which I didn't deny, but at any event.
link |
Yeah, that's true. That's true. Can you say why we know that black holes exist?
link |
Right. So it's an interesting question because black holes were considered a theoretical construct.
link |
And Einstein even denied their existence in 1939. But then in the mid 1960s,
link |
quasars were discovered. These are very bright sources of light,
link |
a hundred times brighter than their host galaxy, which are point like at the center of galaxies.
link |
And it was immediately suggested by Ed Salpeter in the West and by Yakov Zeldovich in the East,
link |
that these are black holes that accrete gas, collect gas from their host galaxy that are
link |
being fed with gas. And they shine very brightly because as the gas falls towards the black holes,
link |
just like water running down the sink, the gas swirls and then rubs against itself and heats up
link |
and shines very brightly because it's very hot close to the black hole by viscosity.
link |
It heats up. And in the case of black holes, it's the turbulence, the turbulent viscosity
link |
that causes it to heat up. So we get these very bright sources of light just from black holes
link |
that are supposed to be dark. Nothing escapes from them, but they create a violent environment
link |
where gas moves close to the speed of light and therefore shines very brightly,
link |
much more than any other source in the sky. And we can see these quasars all the way to
link |
the edge of the universe. So we have evidence now that when the universe was about 7% of its
link |
present age, infant, already back then, you had black holes of a billion times the mass of the
link |
sun, which is quite remarkable. It's like finding giant babies in a nursery. How can these black
link |
holes grow so fast? Less than a billion years after the Big Bang, you already have a billion times
link |
the mass of the sun in these black holes. And the answer is presumably there are very quick
link |
processes that build them up. They build quickly. Very quickly. And so we see those black holes.
link |
And that was found in the mid 1960s, but in 2015, exactly 100 years after Einstein came up with his
link |
theory of gravity, the LIGO observatory detected gravitational waves. And these are just ripples
link |
in space and time. So according to Einstein's theory, the innovation, the ingenuity of Einstein's
link |
theory of gravity that was formulated in November 1915 was to say that space and time
link |
are not rigid. You know, they are, they respond to matter. So for example, if you have two black
link |
holes and they collide, it's just like a stone being thrown into the surface of a pond. They
link |
generate waves, disturbances in space and time that propagate out at the speed of light. These
link |
are gravitational waves. They create a space time storm around them. And then the waves go
link |
all the way through the universe and reach us. And if you have a sensitive enough detector like
link |
LIGO, you can detect these waves. And so it was not just the message that we received for the
link |
first time, gravitational waves, but it was the messenger. So there are two aspects to it. One
link |
is the messenger, which is gravitational wave. For the first time, we're detected directly.
link |
And the second was the message, which was a collision of two black holes, because we could
link |
see the pattern of the ripples in space and time. And it was fully consistent with the prediction
link |
that Schwartz had made for how a black, the space time around the black hole is, because when two
link |
black holes collide, you can sort of map from the message that you get, you can reconstruct what
link |
really happened. And it's fully consistent. And in 2017 and 2020, there's two Nobel prizes.
link |
That's right. That had to do with the black holes. Can you maybe describe in the same
link |
massive way that you've already been doing what those Nobel prizes were given for?
link |
Yeah. So the 2017 was given for the LIGO collaboration for discovering
link |
gravitation waves from collisions of black holes. And the 2020 Nobel prize in physics
link |
was given for two things. One was theoretical work that was done by Roger Penrose in the 1960s,
link |
demonstrating that black holes are inevitable when stars collapse. And it was mostly mathematical
link |
work. And actually, Stephen Hawking also contributed significantly to that frontier. And
link |
unfortunately, he is not alive, so he could not be honored. So Penrose received it on his own.
link |
And then two other astronomers received it as well, Andrea Ghez and Reinhard Genzel,
link |
and they provided conclusive evidence that there is a black hole at the center of the Milky Way
link |
galaxy that weighs about four million times the mass of the sun. And they found the evidence from
link |
the motion of stars very close to the black hole, just like we see the planets moving around the
link |
planets moving around the sun. There are stars close to the center of the galaxy, and they are
link |
orbiting at very high speeds of other thousands of kilometers per second, or thousands of miles
link |
per second. Think about it, which can only be induced at those distances if there is a four
link |
million solar mass object that is extremely compact. And the only thing that is compatible
link |
with the constraints is a black hole. And they actually made a movie of the motion of these
link |
stars around the center. One of them moves around the center over a decade, over timescales that
link |
we can monitor. And it was a breakthrough in a way. So combining LIGO with the detection of
link |
a black hole at the center of the Milky Way and in many other galaxies like quasars,
link |
now I would say black hole research is vogue. It's very much in fashion. We saw it back in
link |
2016 when we established the black hole initiative. You saw that there is this excitement about in
link |
breakthroughs and discoveries around black holes, which are probably one of the most fascinating
link |
objects in the universe. It's up there. They're both terrifying and beautiful, and they capture
link |
the entirety of the physics that we know about this universe. I should say the question is,
link |
where is the nearest black hole? Can we visit it? I wrote a paper with my undergraduate student,
link |
Amir Siraj, suggesting that perhaps if there is one in the solar system, we can detect it.
link |
I don't know if you heard, but there is a claim that maybe there is a Planet 9 in the solar system
link |
because we see some anomalies at the outer parts of the solar system. So some people suggested
link |
maybe there is a planet out there that was not yet detected. So people searched for it,
link |
didn't find it. It weighs roughly five times the mass of the Earth. And we said, okay, maybe you
link |
can't find it because it's a black hole that was formed early in the universe.
link |
So where do you stand on that?
link |
It could be that the dark matter is made of black holes of this mass. We don't know what
link |
the dark matter is made of. It could be black holes. So we said, but there is an experimental
link |
way to test it. And the way to do it is because there is the ore cloud of icy rocks in the outer
link |
solar system. And if you imagine a black hole there, every now and then, a rock will pass
link |
close enough to the black hole to be disrupted by the very strong gravity close to the black hole.
link |
And that would produce a flare that you can observe. And we calculated how frequently these
link |
flares should occur. And with LSSD on the Vera Rubin Observatory, we found that you can actually
link |
test this hypothesis. And if you don't see flares, then you can put limits on the existence of a
link |
black hole in the solar system. It would be extremely exciting if there was a black hole,
link |
if Planet Nine was a black hole, because we could visit it and we can examine it.
link |
And it will not be a matter of an object that is very removed from us.
link |
Another thing I should say is, it's possible that the black hole affected life on Earth.
link |
The black hole at the center of the Milky Way. How? You know, that black hole right now is
link |
dormant. It's very faint. But we know that it flares. When a star like the Sun comes close to
link |
it, the star will be spaghettified, basically become a stream of gas, like a spaghetti. And then
link |
the gas would fall into the black hole and there would be a flare. And this process happens once
link |
every 10,000 years or so. So we expect that, you know, these flares to occur every 10,000 years.
link |
But we also see evidence for the possibility that gas clouds were disrupted by the black hole,
link |
because the stars that are close to the black hole are residing in a single or two planes.
link |
And the only way you can get that is if they formed out of a disk of gas, just like the
link |
planets in the solar system formed. So there is evidence that gas fell into the black hole and
link |
powered possibly a flare. And these flares produce X rays and ultraviolet radiation that could damage
link |
life if the Earth was close enough to the center of the galaxy. Where we are right now, it's not
link |
very risky for us. But there is a theoretical argument that says the solar system, the Sun,
link |
was closer to the galactic center early on, and then it migrated outwards. So maybe in the early
link |
stage of the solar system, the conditions were affected, shaped by these flares
link |
of the black hole at the center of the galaxy. And that's why for the first two billion years,
link |
there wasn't any oxygen in the atmosphere, who knows. But it's just interesting to think that
link |
from a theoretical concept that Einstein resisted in 1939, it may well be that black holes have
link |
influence on our life. And that it's just like discovering that some stranger affected your
link |
family and in a way, your life. And if that happens to be the case, a second Nobel Prize
link |
should be given not for just the discovery of this black hole at the center of the galaxy,
link |
but perhaps for the Nobel Prize in chemistry for the effect that it had.
link |
But the effect for the interplay that resulted in some kind of,
link |
yeah, the chemical effect, biology, I mean, all those kinds of things in terms of
link |
the emergence of life and the creation of a habitable environment. That's so fascinating.
link |
And of course, like you said, dark matter, like black holes have some...
link |
They could be the dark matter in principle, yes. We don't know what the dark matter is at the moment.
link |
Does it make you sad? So you've had an interaction and perhaps a bit of a friendship
link |
with Stephen Hawking. Does it make you sad that he didn't win the Nobel?
link |
Well, all together, I don't assign great importance to prizes because...
link |
You know, Jean Paul Satter, who I admire as a teenager because I was interested in philosophy.
link |
When I grew up on a farm in Israel, I used to collect eggs every afternoon and I would drive
link |
the tractor to the hills of our village and just think about philosophy, read philosophy books.
link |
And Jean Paul Satter was one of my favorites. And he was honored with the Nobel Prize in literature.
link |
He was a philosopher primarily, existentialist. And he said, the hell with it, why should I give
link |
special attention to this committee of people that get their self importance from awarding me
link |
the prize? Why does that merit my attention? So he gave up on the Nobel Prize.
link |
And, you know, there are two benefits to that. One, that you don't, you're not working your
link |
entire life in the direction that would satisfy the will of other people. You know, you work
link |
independently, you're not after these honors. Just for the same reason that if you're not
link |
living your life from making a profit or money, you can live a more fulfilling life because you're
link |
not being swayed by the wind, you know, of how to make money and so forth. The second aspect of
link |
it is, you know, that very often, you know, these prizes, they, they distort the way we do science
link |
because instead of people willing to take risks, and instead of having announcements only after
link |
a group of people converges with a definite result, you know, the natural progression of
link |
science is based on trial and error, you know, so reporting some results and perhaps they're wrong,
link |
but then other people find perhaps better evidence and then you figure out what's going on. And
link |
that's the natural way that science is, you know, it's a learning experience. So if you give the
link |
public an image by which scientists are always right, you know, and, and, and, you know, some of
link |
my colleagues say we must do that because otherwise the public will never believe us that global
link |
warming is really taking place. But that's not true because the public will really believe you
link |
if you show the evidence. So the point is you should be sincere when the evidence is not
link |
absolutely clear or whether there are disputes about the interpretation of the evidence, we
link |
should show ourselves, you know, the king is naked. Okay. There is no point in pretending that the
link |
king is dressed, saying that scientists are always right. Scientists are wrong frequently.
link |
And the only way to make progress is by evidence, giving us the support that we need to make
link |
airtight arguments. So when you say global warming is taking place, if the evidence is
link |
fully supportive, there are no holes in the argument, then people will be convinced because
link |
you're not trying to fool them. When the evidence was not complete, you also show them that the
link |
evidence is not complete. And when there's holes, you show that there's holes and here's the
link |
methodology we're using to try to close those holes. Exactly. Let's be sincere. Why pretend?
link |
So if there were no, in a world where there were, there were no prizes, no honours,
link |
we would act like kids, as I said before, we would really be focusing on the ball and not
link |
on the audience. Yeah, the prizes get in the way and it's, it's so powerful. Do you think
link |
in some sense the few people that have turned down the prize made a much more powerful statement?
link |
I don't know if you're familiar in the space of mathematics with the Fields Medal
link |
and a good girl at Perlman who turned down the prize. So he, I've committed, one of the reasons
link |
I started this podcast is I'm going to definitely talk to Putin, I'm definitely talking to Perlman
link |
and people keep telling me it's impossible. I love hearing that because I'll talk to both.
link |
Anyway, but do you have a sense of why he turned down the prize and is that a powerful statement
link |
to you? Well, what I read is that you're talking about the mathematician. The mathematician turned
link |
down the prize. What I read is that he was disappointed by the response of the community,
link |
the mainstream community, the mathematicians, to his earlier work where they dismissed it,
link |
they didn't attend to the details and didn't treat him with proper respect because he was not
link |
considered one of them. And I think that speaks volumes about the current scientific culture
link |
which is based on groupthink and on social interaction rather than on the merit of the
link |
argument and on the evidence in the context of physics. So in mathematics there is no empirical
link |
basis, you're exploring ideas that are logically consistent, but nevertheless there is this
link |
groupthink. And I think he was so frustrated with his past experience that he didn't even bother to
link |
publish his papers, he just posted them on the archive and in a way saying, you know,
link |
I know what the answer is, go look at it. And then again, in the long arc of history,
link |
his work on archive will be remembered and all the prizes, most of the prizes will be forgotten.
link |
That's what people don't kind of think about. When you look at Roger Penrose, for example,
link |
is another fascinating figure. You know, it's possible, and forgive me if I'm sure I'm ignorant,
link |
but he's also did some work on consciousness. He's been one of the only people who spoke about
link |
consciousness, which for the longest time is still arguably outside of the realm of the sciences.
link |
It's still seen as a taboo subject. And he was brave enough to explore it from a physics
link |
perspective, from just a philosophical perspective, but with the rigor, like proposing different
link |
kind of hypotheses of how consciousness might be able to emerge in the brain. And it's possible
link |
that that is the thing he's remembered for, if you look hundred years from now, right? As opposed
link |
to the work in the black holes, which fits into the kind of, like the fits into what the current
link |
scientific community allows to be the space of what is and isn't science.
link |
Yeah, it's really interesting to look at people that are innovators, where in some phases of their
link |
career, their ideas fit into the social structure that is around them, but in other phases,
link |
it doesn't. And when you look at them, they just operated the same way throughout.
link |
And it says more about their environment than about them.
link |
Well, yeah, I don't know if you know who Max Tagmark is.
link |
Yeah, of course. He's a friend of mine.
link |
I just recently talked to him again. And he, I mean, he was a little bit more explicit about
link |
saying, you know, being aware, which is something I also recommend is like being aware where the
link |
scientific community stands and doing enough to get, like move along into your career in your
link |
career. And yeah, it's the necessary evil, I suppose. If you are one of those out of the box
link |
thinkers that just naturally have this childlike curiosity, which Max definitely is one of them,
link |
is sometimes you have to do some stuff that fits in, you publish and you get 10 years and all those
link |
kinds of things. But the tenure is a great privilege because it allows you to, in principle,
link |
explore things that are not accepted by others. And unfortunately, it's not being taken advantage
link |
of by most people. And it's a waste of a very precious resource.
link |
Yeah, absolutely. The space that you kind of touched on, that's full of theories and is perhaps
link |
detached from appreciation of empirical evidence or longing for empirical evidence or grounding
link |
in empirical evidence is the theoretical physics community and the interest in unifying the laws
link |
of physics and with the theory of everything. I'm not sure from which direction to approach
link |
this question, but how far away are we from arriving at a theory of everything, do you think?
link |
And how important is it to try to arrive at it at this kind of goal of this beautiful,
link |
simple theory that unlocks the very fundamental basis of our nature as we know it? And what
link |
are the kinds of approaches we need to take to get there?
link |
Yeah, so in physics, the biggest challenge is to unify quantum mechanics with gravity.
link |
And I believe that once we have experimental evidence for how this happens in nature,
link |
in systems that have quantum mechanical effects, but also gravity is important,
link |
then the theory will fall into our lap. But the mistake that is made by the community right
link |
now is to come up with the right theory from scratch. And Einstein gave the illusion that you
link |
can just sit in your office and understand nature when he came up with his general theory
link |
of relativity. But first of all, perhaps he was lucky, but it's not a rule. The rule is that you
link |
need evidence to guide you, especially when dealing with quantum mechanics, which is really
link |
not intuitive. And so there are two places where the two theories meet. One is black holes.
link |
And there is a puzzle there. It's called the information paradox. In principle, you can throw
link |
the encyclopedia Britannica into a black hole. It's a lot of information. And then it will be
link |
gone because a black hole carries only three properties or qualities, the mass, the charge,
link |
and the spin, according to Einstein. But then when Hawking tried to bring in quantum mechanics
link |
to the game, he realized that black holes have a temperature and they radiate. This is called
link |
Hawking radiation. And it was sort of anticipated by Jacob Bekenstein before him. And Hawking wanted
link |
to prove Bekenstein wrong and then figure this out. And so what it means is black holes eventually
link |
evaporate. And they evaporate into radiation that doesn't carry this information, according to
link |
Hawking's calculation. And then the question is, according to quantum mechanics, information must
link |
be preserved. So where did the information go if a black hole is gone? And where is the information
link |
that was encoded in the encyclopedia when it went into the black hole? And to that question,
link |
we don't have an answer yet. It's one of those puzzles about black holes. And it touches on the
link |
interplay between quantum mechanics and gravity. Another important question is, what happened
link |
at the beginning of the universe? What happened before the Big Bang? And by the way, on that,
link |
I should say, you know, there are some conjectures. In principle, if we figure it out, if we have a
link |
theory of quantum gravity, it's possible to imagine that we will figure out how to create a universe
link |
in the laboratory. By irritating the vacuum, you might create a baby universe. And if we do that,
link |
it will offer a solution to what happened before the Big Bang. Perhaps the Big Bang emerged from
link |
the laboratory of another civilization. So it's like, baby universes are being born out of laboratories.
link |
And inside the baby universe, you have a civilization that brings to existence a new baby
link |
universe, just like humans, right? We have babies and they make babies. So in principle,
link |
that would solve the problem of why there was a Big Bang, and also what happened before the
link |
Big Bang. So we came, our umbilical cord is connected to a laboratory of a civilization that
link |
produced our universe once it figured out quantum gravity. It's baby Big Bangs all the way down.
link |
It's just Big Bangs all the way down. So if we collect data about how the universe started,
link |
we could potentially test theories, or it can educate us about how to unify quantum mechanics
link |
and gravity. If we could, if we get any information about what happens near the singularity of a
link |
black hole, you know, if we, if we get a sense of, you know, somehow we learn what happens at the
link |
same, that would educate. So there are places where we can search for evidence, but it's very
link |
challenging, I should say. And my point is, you know, the string theories, they decided that they
link |
know how to approach the problem, but they don't have a single theory. There is a multitude of
link |
theories, and it's not tightly constrained, and they cannot make predictions about black holes,
link |
or about the beginning of the universe. So, so at the moment, I say we're at a loss. And the way I
link |
feel about this concept of the theory of everything, we should wait until we get enough evidence to
link |
guide us. And until then, you know, there are many important problems that we can address,
link |
you know, why, why bang our head against the wall on a problem for which we have no guidance?
link |
Right. We don't have a good dance partner in terms of evidence. There's not, I mean, it'd be
link |
interesting, just like you said, I mean, the lab is one place to create universes or black holes,
link |
but it'd be fascinating if there is indeed a black hole in our solar system that you can
link |
interact with. So the problem with the origin of the universe is all you can do is collect data
link |
about it, right? You can't interact with it. Well, you can, for example, detect gravitational waves
link |
that emerged from that. And, you know, there is an effort to do that. And that could potentially
link |
tell us something. But yeah, it's a challenge. And that's why we're stuck. So I should say,
link |
despite what physicists portray that, you know, we live through an exceptional growth in our
link |
understanding of the universe, we're actually pretty much stuck, I would say, because we don't
link |
know the nature of the dark matter, most of the matter in the universe. We don't know what it is.
link |
And we don't know how the universe started. We don't know what happens in the interior of a black
link |
hole. Because you've thought quite a bit about dark matter as well. Do you have any kind of
link |
hypothesis, interesting hypothesis? We already mentioned a few about what is dark matter and
link |
what are the possible paths that we could take to unlock the mystery of dark? What is dark matter?
link |
Yeah, so what we need is some anomalies that would hint what the nature of the dark matter is,
link |
or to detect it in the laboratory. There are lots of laboratory experiments
link |
searching, but it's like searching for a needle in a haystack, because there are so many possibilities
link |
for the type of particle that it may be. But maybe at some point, you know, we'll find either a
link |
particle or black holes as dark matter or something else. But at the moment...
link |
Can you also maybe start to interrupt, to comment about what is dark matter? Like what? It's just
link |
the name we're assigned to. What? So most of the community believes that it's a particle
link |
that we haven't yet detected. It doesn't interact with light, so it's dark. But the question is,
link |
what does it interact with and how can we find it? And for many years, physicists were guided by
link |
the idea that it's some extension of the standard model of particle physics. But then they said,
link |
oh, we will find some clues from the Large Hadron Collider about its nature. Or maybe it's related
link |
to supersymmetry, which is a new symmetry that we haven't found any evidence for. In both cases,
link |
the Large Hadron Collider did not give us any clues. And other people search for specific types
link |
of particles in the laboratory and didn't find any. A couple of years ago, actually,
link |
around the time that I worked on Oumuamua, I also worked on the possibility that the dark
link |
matter particles may have a small electric charge, which is a speculation. But nobody complained about
link |
it. And it was published. And I regarded more of a speculation than the artificial origin of
link |
Oumuamua. And to me, as far as I'm concerned, I applied the same scientific tools in both cases.
link |
There is an anomaly that led me to that discussion, which has to do with the hydrogen being called in
link |
the early universe more than we expected. So we suggested maybe the dark matter particles have
link |
some small charge. But you deal with anomalies by exploring possibilities. That's the only way
link |
to do it. And then collecting more data to check those. And searching for technological signatures
link |
is the same as any other part of our scientific endeavor. We make hypotheses and we collect data,
link |
and I don't see any reason for having a taboo on this subject.
link |
And your childlike, open minded excitement and approach to science, I think to anyone listening
link |
to this is truly inspiring. I mean, the question I think is useful to ask is by way of advice
link |
for young people. A lot of young people listen to this, whether from all over the world,
link |
and teenagers, undergraduate students, even graduate students, even be like even young faculty,
link |
even older faculty, they're all young and hard. Like there's many young and hard. Do you have
link |
advice for bullets focused on the traditionally defined sort of young folks like undergraduate?
link |
Do you have advice to give to young people like that today about life, maybe in general,
link |
maybe a life of curiosity in the sciences? Definitely. Well, first I should confess that
link |
I enjoy working with young people much more than with senior people. And the reason is they don't
link |
carry a baggage of prejudice. They're not so self centered. They're open to exploration.
link |
My advice, I mean, one of the lessons that took me a while to learn, and I should say I lost
link |
important opportunities as a result of that. So that I would regard it as a mistake on my behalf
link |
was to believe experts. So quote unquote. So on a number of occasions, I would come up with an
link |
original idea, and then suggest it to an expert, someone that works in the same field for a while.
link |
And the expert would dismiss it most of the time because it's new and was not explored,
link |
not because of the merit. And then what happened to me several times is that someone else would
link |
listen to the conversation or would hear me suggesting it. And I would give up because the
link |
expert said no. And then that someone else, you know, would develop it so that it becomes the
link |
so that it becomes the hottest thing in this field. And it happened, you know, once it happened to me
link |
multiple times, I then realized the hell with the experts, you know, like, they don't know what
link |
they're talking. They're just repeating them. Yes, they don't think creatively, they are being
link |
threatened by innovation. Okay. And it's the natural reaction of someone that cares about
link |
their ego more than about the matter that we are discussing. And so I said, I would not,
link |
I don't care how many likes I have on Twitter. I don't care whether the experts say one thing
link |
or another, I will basically exercise my judgment and do the best I can, you know,
link |
turns out that I'm wrong. I made a mistake, you know, that's part of the of the scientific endeavor,
link |
you know, and it took me a while to recognize that and it was a lot of wasted opportunities. So
link |
to the young people, I would recommend, don't listen to experts, carve your own path. Now,
link |
of course, you will be wrong. You should learn from experience, just like kids do. But do it yourself.
link |
Your father died in 2017. Your mother died in 2019. Do you miss them? Very much so.
link |
Is there a memory that fond memory that stands out or maybe
link |
be whatever you learned from them? From my mother, I mean, she was very much my inspiration for
link |
pursuing intellectual work because she studied at the university. And then because of the
link |
Second World War, after the Second World War, she was born in Bulgaria, they immigrated to
link |
Israel and and she left university to work on a farm. And later in life, when all the kids left
link |
home, she went back to the university and finished the PhD. But she planted in me the intellectual
link |
curiosity and valuing learning as or acquiring knowledge as a very important element in life.
link |
And and my love with philosophy came from attending classes that she took at the university.
link |
When I was a teenager, I was fortunate to go to some of these and they inspired me later on. And
link |
I'm very different than my colleagues, as you can tell, because my upbringing was quite different.
link |
And the only reason I'm doing physics or astrophysics is because of circumstances. I
link |
at age 18, I was asked to serve in the military. And the only way for me to pursue intellectual
link |
work was to work on physics, because that was the closest to philosophy. And I was good at physics.
link |
So they admitted me to an elite program called LPO that allowed me to finish my PhD at age 24.
link |
And to actually propose the first international project that was funded by the Star Wars initiative
link |
for Ronald Reagan. And that brought me brought me to the US to visit Washington DC, where we were
link |
funded from. And then on one of the visits, I went to the Institute for Advanced Study at Princeton
link |
and met John Bacal that later offered me a five year fellowship there under the condition that
link |
I'll switch to astrophysics, at which point, you know, I said, okay, I cannot give up on this
link |
opportunity. I'll do it, switch to astrophysics. It felt like a forced marriage kind of arranged
link |
marriage. And then I was offered the position at Harvard, because nobody wanted that.
link |
They first selected someone else. And that someone said, I don't want to become a junior
link |
faculty at the Harvard astronomy department, because the chance for being promoted are very small.
link |
So he took another job. And then I was second in line. They gave it to me. I didn't care much,
link |
because I could go back to the farm any day, you know. And after three years, I was tenured.
link |
And eventually, a decade later, became the chair of this department and served for nine years as
link |
the chair of the astronomy department at Harvard. But at that point, it became clear to me that
link |
I'm actually married to the love of my life, even though it was an arranged marriage. There are many
link |
philosophical questions in astrophysics that we can address. But I'm still very different than my
link |
colleagues, you know, that were focusing on technical skills in getting to this job. So my
link |
mother was really extremely instrumental in planting the seeds of thinking about the big picture
link |
in me. Then my father, he was, you know, he was working in the farm. And we didn't speak much,
link |
because we sort of understood each other without speaking. But what he gave me is a sense of,
link |
you know, that it's more important to do things than to talk about them.
link |
I love the, I mean, my apologies, but MIT, mind and hand, I love that there's
link |
that the root of philosophy that you gain from your mom and the hand that action is all that,
link |
ultimately, in the end, matters from your dad. That's really powerful. If we could take a small
link |
detour into philosophy, is there by chance any books, authors, whether philosophical or not,
link |
you mentioned Sartre that stand out to you that were formative in some small or big way that
link |
perhaps you would recommend to others, maybe when you were very young or maybe later on in life?
link |
Well, actually, yeah, I, you know, I read the number of existentialists that
link |
appealed to me because they were authentic. You know, Sartre, you know, he declined the
link |
Nobel Prizes we discussed, but he also was mocking people that pretend to be something
link |
better than they are, you know, he was living an authentic life that is sincere. And that's
link |
what appealed to me. And Albert Camus was another French philosopher that advocated existentialism.
link |
You know, that really appealed to me. That's probably my favorite existentialist Camus.
link |
Yeah. And he died at a young age in an accident, unfortunately. And then, you know, people like
link |
Nietzsche that, you know, broke conventions. And I noticed that Nietzsche is still extremely
link |
popular. You know, that's quite surprising. He appeals to the young people of today.
link |
And the people that, it's the children, it's the childlike wonder about the world. And
link |
he was unapologetic. You know, it's like most philosophers have a very strict
link |
adherence to terminology into the practices, academic philosophers. And Nietzsche was full
link |
of contradictions. And he just, I mean, he was just this big kid with opinions and thought deeply
link |
about this world. And people are really attracted to that. And surprisingly, there's not enough
link |
people like that throughout history of philosophy. And that's why I think this is still drawn to him.
link |
Yeah. To me, what stands out is his statement that the best way to corrupt the mind of young
link |
people is to tell them that they should agree with the common view, you know. And, you know,
link |
it goes back to the thread that went throughout discussion. Yes. You've kind of suggested that
link |
we ought to be humble about our very own existence and that our existence lasts only a short time.
link |
We talked about you losing your father and your mother. Do you think about your own mortality?
link |
Oh, yeah. Are you afraid of death? I'm not afraid. You know what Epichorus,
link |
actually Epichorus was a very wise person. According to Lucretius, Epichorus didn't live
link |
anything in writing, but he said that he's never afraid of death because as long as he's around,
link |
death is not around. And when death will be around, he will not be around. So he will never
link |
meet death. So why should you be worried about something you will never meet? You know, and
link |
it's an interesting philosophy of life. You know, you shouldn't be afraid of something that you
link |
will never encounter, right? But there's a finiteness to this experience. We live every day. I mean,
link |
I think of it for being honest. We live every day as if it's going to last forever. We often kind
link |
of don't contemplate the fact that it ends. You kind of have plans and goals and you have these
link |
possibilities. You have a kind of lingering thought, especially as you get older and older and older,
link |
that this is, especially when you lose friends, then you start to realize, you know, it doesn't.
link |
But I don't know if you're really cognizant of that. I mean, because...
link |
But you have to be careful not to be depressed by it because otherwise you lose the vitality,
link |
right? So I think the most important thing to draw from knowing that you are short lived
link |
is a sense of appreciation that you're alive. That's the first thing. But more importantly,
link |
a sense of modesty because how can anyone be arrogant if they kept at the same time this
link |
notion that they are short lived? I mean, you cannot be arrogant because anything that you
link |
advocate for, you know, you will not be around to do that in a hundred years. So people will
link |
just forget and move on, you know? And if you keep that in mind, you know, the scissors in
link |
ancient Rome, they had a person next to them telling them, don't forget that you are mortal.
link |
You know, there was a person with that duty because the scissors thought that they are all
link |
powerful, you know? And they had, for a good reason, someone they hired to whisper in their ear,
link |
don't forget that you are mortal. Well, you're somebody one of the most
link |
respected, famous scientists in the world sitting on a farm gazing up at the stars.
link |
So you seem like an appropriate person to ask the completely inappropriate question of
link |
what do you think is the meaning of it all? What's the meaning of life?
link |
That's an excellent question. And if we ever find an alien that we can converse with,
link |
I would like to answer this. I would like to ask for an answer to this question because...
link |
Would they have a different opinion, you think? Well,
link |
they might be wiser because they lived around for a while, but I'm afraid they will be silent.
link |
I'm afraid they will not have a good answer. And I think
link |
it's the process that you should get satisfied by, the process of learning you should enjoy.
link |
Okay, so it's not so much that there is a meaning. In fact, there is, as far as I can tell,
link |
things just exist, you know? And it's... I think it's inappropriate for us to assign
link |
meaning for our existence because, you know, as a civilization, we will eventually perish,
link |
and nothing will be, you know, just another planet on which life died, you know? And
link |
if you look at the big scheme of things, who cares? Like, who cares? And how can we assign
link |
significance to what we are doing, you know? So if you say the meaning of life is this,
link |
well, it will not be around in a billion years. So what, you know, it cannot be the meaning of
link |
life because life, you know, nothing will be around. So I think we should just enjoy the process.
link |
And, you know, it's like many other things in life, you enjoy good food, okay? And you can enjoy
link |
learning. Why? Because it makes you appreciate better the environment that you live in. And
link |
sometimes people think religion, for example, is in conflict with science, spirituality,
link |
in conflict. That's not true. If you see a watch and you look at it from the outside,
link |
you know, you might say, oh, that's interesting. But then if you start to open it up and learn
link |
about how it works, you appreciate it more. So science is the way to learn about how the world
link |
works. And it's not in conflict to the meaning that you assign to all of this, but it helps you
link |
appreciate the world better. So in fact, I would think that a religious person should promote
link |
science because it gives you a better appreciation of what's around you. You know, it's like, you
link |
know, if you buy in a grocery, buy something, you know, a bunch of fruits that are packed together,
link |
and you can't see from the outside exactly what kind of fruits are inside. But if you open it up
link |
and study, you appreciate better the merchandise that you get, right? So you pay the same amount
link |
of money, but at least you know what's inside. So why don't we figure out what the world is about,
link |
you know, what the universe contains, what is the dark matter? It will help us appreciate,
link |
you know, the bigger picture. And then you can assign your own flavor to what it means, you know.
link |
Ali, I think I'm truly grateful that a person like you exists at the center of the scientific
link |
community gives me faith and hope about this, this big journey that we call science. So
link |
thank you for writing the book you wrote recently. You have many other books and articles that I
link |
think people should definitely read. And thank you for wasting all this time with me as a truly
link |
an honor. Thank you so much. Was not a waste at all. And thank you for having me. I learned a lot
link |
from your questions and your remarks. Thank you. Thank you. Thanks for listening to this
link |
conversation with Avi Loeb. And thank you to our sponsors. Zero fasting app for intermittent fasting,
link |
element electrolyte drink, sunbasket meal delivery service, and pessimist archive history podcast.
link |
So the choice is a fasting app, fasting fuel, fast breaking, delicious meals, and a history
link |
podcast that has very little as far as I know to do with fasting. Choose wisely, my friends. And if
link |
you wish, click the sponsor links below to get a discount and to support this podcast. And now
link |
let me leave you with some words from Albert Einstein. The important thing is not to stop
link |
questioning. Curiosity has its own reason for existence. One cannot help but be in awe when
link |
he contemplates the mysteries of eternity, of life, of the marvelous structure of reality.
link |
It is enough if one tries merely to comprehend a little of this mystery every day.
link |
Thank you for listening and hope to see you next time.