There's no reason to think that the ocean ends just beyond your horizon.

And likewise, there's no reason to think that the aftermath of our big bang

ends just at the boundary of what we can see.

Indeed, there are quite strong arguments that it probably goes on about 100 times further.

And it may even go on so much further that all combinatorials are replicated.

And there's another set of people like us sitting in a room like this.

The following is a conversation with Lord Martin Rees,

emeritus professor of cosmology and astrophysics at Cambridge University

and cofounder of the Center for the Study of Existential Risk.

This is the Lex Friedman podcast.

To support it, please check out our sponsors in the description.

And now, dear friends, here's Martin Rees.

In your 2020 Scientific American article, you write that, quote,

today we know that the universe is far bigger and stranger than anyone suspected.

So what do you think are the strangest, maybe the most beautiful,

or maybe even the most terrifying things lurking out there in the cosmos?

Well, of course, we're still groping for any detail understanding of the remote parts of the universe.

But of course, what we've learned in the last few decades is really two things.

First, we've understood that the universe had an origin about 13.8 billion years ago

in a so called Big Bang, a hot 10 states whose very beginnings are still shrouded in mystery.

And also, we've learned more about the extreme things in it,

black holes, neutron stars, explosions of various kinds.

And one of the most potentially exciting discoveries in the last 20 years, mainly in the last 10,

has been the realization that most of the stars in the sky are orbited by retinas of planets,

just as the sun is orbited by the Earth and the other familiar planets.

And this, of course, makes the night sky farmer interesting.

What you see up there aren't just points of light, but they're planetary systems.

And that raises the question, could there be life out there?

And so that is an exciting problem for the 21st century.

So when you see all those lights out there, you immediately imagine

all the planetary worlds that are around them.

And they potentially have all kinds of different lives,

living organisms, life forms, or different histories.

That we don't know at all.

We know that these planets are there.

We know that they have masses and orbits, rather like the planets of our solar system.

But we don't know at all if there's any life on any of them.

I mean, it's entirely logically possible that life is unique to this Earth.

Doesn't exist anywhere.

On the other hand, it could be that the origin of life is something which happens routinely,

given conditions like the young Earth, in which case there could be literally billions

of places in our galaxy where some sort of biosphere has evolved.

And settling where the truth lies between those two extremes

is a challenge for the coming decades.

So certainly we're either lucky to be here or very, very, very lucky to be here.

I guess that's the difference.

Where do you fall, your own estimate, your own guess on this question?

Are we alone in the universe, do you think?

I think we foolish to give any firm estimate because we just don't know.

And that's just an example of how we are depending on greater observations

and also, incidentally, in the case of life.

We've got to take account of the fact that, as I always say to my scientific colleagues,

biology is a much harder subject than physics.

And most of the universe, as we know about, could be understood by physics.

But we've got to remember that even the smallest living organism, an insect,

is far more complicated with layer on layer complexity

than the most complicated star or galaxy.

You know, that's the funny thing about physics and biology.

The dream of physicists in the 20th century and maybe this century

is to discover the theory of everything.

And there's a sense that once you discover that theory, you will understand everything.

If we unlock the mysteries of how the universe works,

would you be able to understand how life emerges

from that fabric of the universe that we understand?

I think the phrase theory of everything is very misleading

because it's used to describe a theory which unifies the three laws of microphysics,

electricity, magnetism, and weak interaction with gravity.

So it's an important step forward for particle physicists.

But the lack of such a theory doesn't hold up any other scientists.

Anyone doing biology or most of physics is not held up at all

through not understanding subnuclear physics.

They're held up because they're dealing with things that are very complicated.

And that's especially true of anything biological.

So what's holding up biologists is not a lack of the so called theory of everything.

It's the inability to understand things which are very complicated.

What do you think we'll understand first?

How the universe works or how the human body works deeply?

Like from a fundamental, deep level?

Well, I think, and perhaps we can come back to it later,

that there are only limited prospects of ever being able to understand

with unedged human brains the most fundamental theories

linking together all the forces of nature.

I think that may be a limitation of the human brains.

But I also think that we can, perhaps aided by computer simulations,

understand a bit more of the complexity of nature.

But even understanding a simple organism from the atom up is very, very difficult.

And I think extreme reductionists have a very misleading perception.

They tend to think that in a sense we are all solutions to Freudian's equation.

But that isn't the way we'll ever understand anything.

It may be true that we are reductionists in a sense if we believe

that that's the case, we don't believe in any special life force in living things.

But nonetheless, no one thinks that we can understand a living thing

by solving Freudian's equation.

To take an example which isn't as complicated,

lots of people study the flow of fluids like water.

Why waves break, why flows go turbulent, things like that.

This is a serious branch of applied mathematics and engineering.

And in doing this, you have concepts of viscosity, turbulence, and things like that.

Now, you can understand quite a lot about how water behaves

and how waves break in terms of those concepts.

But the fact that any breaking wave is a solution

of Freudian's equation for tens of 30 particles,

even if you could solve that, which you clearly can't,

would not give you any insight.

So the important thing is that every science has its own irreducible concepts

in which you get the best explanation.

So it may be in chemistry, things like balance, in biology,

concepts in cell biology,

and in ecology, there are concepts like imprinting, et cetera.

And in psychology, there are other concepts.

So in a sense, the sciences are like a tall building

where you have basic physics most fundamental,

then the rest of physics, then chemistry, then cell biology, et cetera,

all the way up to the, I guess, economists and the penthouse and all that.

We have that.

And that's true in a sense, but it's not true

that it's like a building in that it's made unstable by an unstable base,

because if you're a chemist, biologist, or an economist,

you're facing challenging problems,

but they're not made any worse by uncertainty about subnuclear physics.

And at every level, just because you understand the rules of the game

or have some understanding of the rules of the game

doesn't mean you know what kind of beautiful things that game creates.

Right. So if you're interested in birds and how they fly,

then things like imprinting the baby on the mother and all that

and things like that are what you need to understand.

You couldn't even, in principle, solve this vertical equation,

how an albatross wanders for thousands of miles to the southern ocean

and comes back and then coughs up food for its young.

That's something we can understand in a sense and predict the behavior,

but it's not because we can solve it on the atomic scale.

You mentioned that there might be some fundamental limitation to the human brain

that limits our ability to understand something that we can't understand.

To understand some aspect of how the universe works, that's really interesting.

That's sad, actually, to the degree it's true, it's sad.

So what do you mean by that?

I would simply say that just as a monkey can't understand quantum theory

or even Newtonian physics, there's no particular reason

why the human brain should evolve to be well matched

to understanding a deepest aspect of reality.

And I suspect that there may be aspects that we are not even aware of

and couldn't really fully comprehend, but as an intermediate step towards that,

one thing which I think is very interesting possibility

is the extent to which AI can help us.

I mean, I think if we take the example of so called theories of everything,

one of which is string theory, string theory involves very complicated geometry

and structures in 10 dimensions.

And it's certainly, in my view, on the cards that the physics of 10 dimensions,

very complicated geometry, may be too hard for a human being to work through,

but could be worked through by an AI with the advantage of the huge processing power,

which enables them to learn world championship chess within a few hours just by watching games.

So there's every reason to expect that these machines could help us to solve these problems.

And of course, if that's the way we came to understand where the string theory was right,

it should be in a sense frustrating because you wouldn't get the sort of ah ha insight,

which is the greatest satisfaction doing science.

But on the other hand, if a machine churns away a 10 dimensional geometry,

figuring out all the possible origamis and wound up in extra dimensions,

if it comes out at the end, spews out the correct mass of the electron,

the fact that there are three kinds of neutrinos, something like that,

you would know that there was some truth in the theory.

And so we may have a theory which we come to trust because it does predict

it does protect things that we can observe and check,

but we may never really understand the full workings of it to the extent that we do more or less

understand how most phenomena can be explained in a fundamental way.

Of course, in the case of quantum theory,

many people would say, understand if there's still some mystery,

you don't quite understand why it works.

But there could be deeper mysteries when we get to these unified theories,

where there's a big gap between what a computer can print out for us at the end

and what we can actually grasp and think through in our heads.

Yeah, it's interesting that the idea that there could be things a computer could tell us that

is true. And maybe it can even help us understand why it's true a little bit.

But ultimately, it's still a long journey to really deeply understand the whys of it.

Yes, and that's the limitation of our brain.

Well, we can try to sneak up to it in different ways,

given the limitations of our brain.

Have you, I've gotten a chance to spend the day at DeepMind, Dr. Dennis Lasabas.

His big dream is to apply AI to the questions of science,

certainly to the questions of physics.

Have you gotten a chance to interact with them?

Well, I've known quite well. He's one of my heroes, certainly.

I'm sure he would say the same.

And I remember the first time I met him, he said that he was like me.

He wants to understand the universe, but he thought the best thing to do

was to try and develop AI.

And then with the help of AI, he'd stand more chance of understanding the universe.

And I think he's right about that.

And of course, although we're familiar with the way his computers play go and chess,

he's already made contributions to science through

understanding protein folding better than the best human chemists.

And so already he's on the path to showing ways in which computers have the power to learn

and do things by having a bit to analyze enormous samples in a short time

to do better than humans.

And so I think he would resonate for what I just said,

that it may be that in these other fundamental questions,

the computers will play a crucial role.

Yeah. And they're also doing quantum mechanical simulation of electrons.

They're doing control of high temperature plasmus fusion reactors.

Yes. That's a new thing, which is very interesting.

They can suppress the instabilities in these tokamaks better than any other way.

Yeah.

And it's just the march of progress by AIs and science is making big strides.

Do you think an AI system will win a Nobel Prize in the century?

What do you think?

And does that make you sad?

If I can digress and push in a plug for my next book,

it has a chapter saying why Nobel Prizes do more harm than good.

So on a quite separate subject, I think Nobel Prizes do greatly

damage to the percept of the way science is done.

Of course, if you ask who or what deserves the credit for any scientific discovery,

it may be often someone who has an idea,

a team of people who work a big experiment, etc.

And of course, it's the quality of the equipment, which is crucial.

And certainly in the subjects I do in astronomy,

the huge advances we've had come not from us being more intelligent than Aristotle was,

but through us having far, far better data from powerful telescopes on the ground and in space.

And also, incidentally, we've benefited hugely in astronomy from computer simulations,

because if you are a subatomic physicist, then of course you crash together

the particles in the big accelerator like the one at CERN and see what happens.

But I can't crash together two galaxies or two stars and see what happens.

But in the virtual world of a computer, one can do simulations like that.

And the power of computers is such that these simulations can yield a phenomena and insights

which we wouldn't have guessed beforehand.

And the way we can feel by making progress and trying to understand

some of these phenomena, why galaxies have the size and shape they do and all that,

is because we can do simulations tweaking different initial conditions

and seeing which gives the best fit to what we actually observe.

And so that's a way in which we've made progress in using computers.

And incidentally, we also now need them to analyze data,

because one thinks of astronomy as being traditionally a rather data poor subjects,

but the European satellite called Gaia has just put online the speeds and colors

and properties of nearly two billion stars in the Milky Way,

and which we can do fantastic analyses of.

And that of course could not be done at all without just the number of crushing capacitors

computers.

And the new methods of machine learning actually love raw data,

the kind that astronomy provides, organized structured raw data.

Well, indeed, because the reason they really have a benefit over us

is that they can learn and think so much faster.

That's how they can learn to play chess and go.

That's how they can learn to diagnose lung cancer better than a radiologist,

because they can look at 100,000 scans in a few days,

whereas no human radiologist sees that many in lifetime.

Well, there's still a magic to the human intelligence,

to the intuition, to the common sense reasoning.

Well, we hope so for now.

What is the new book that you mentioned?

The book is called If Science is to Save Us.

It's coming out in September, and it's on the big challenges of science,

climate, dealing with biosafety and dealing with cyber safety,

and also it's got chapters on the way science is organized in a universe,

it's an academy, et cetera, and the ethics of science and the education and the limits.

Well, let me actually just stroll around the beautiful and the strange of the universe.

Over 20 years ago, you hypothesized that we would solve the mystery of dark matter by now.

So, unfortunately, we didn't quite yet.

First, what is dark matter and why has it been so tough to figure out?

Well, I mean, we learned that galaxies and other large scale structures,

which are moving around but prevent them flying apart by gravity, would be flying apart

if they only contain the stuff we see, if everything in them was shining,

and to understand how galaxies formed and why they do remain confined the same size.

One has to infer that there's about five times as much stuff producing gravitational forces

than the total amount of stuff in the gas and stars that we see, and that stuff is called dark

matter. That's like this leading name, it's not dark, it's just transparent, et cetera.

And the most likely interpretation is that it's a swarm of microscopic particles

which have no electric charge and the very small cross sections were hitting each other

and hitting anything else. So, they swarm around and we can detect their collective effects.

And when we do computer simulations of how galaxies form and evolve and how they emerge

from the Big Bang, then we get a nice consistent picture if we put in five times as much mass

in the form of these mysterious dark particles. And, for instance, it works better if we think

they're not interacting particles than if we think they're a gas which would have shock waves

and things. So, we know something about the properties of these, but we don't know what they

are. And the disappointment compared to my guess 20 years ago is that particles answering this

description have not yet been found. It was thought that the big accelerator, the Large

Handler Collider at CERN, which is the world's biggest, might have found a new class of particles

which would have been the obvious candidates. And it hasn't. And some people say, well,

doc matter can't be there, etc. But what I would argue is that there's a huge amount of parameter

space that hasn't been explored. There are other kinds of particles called axions which behave

slightly differently, which are good candidates. And there's a factor of 10 powers of 10 between

the heaviest particles that could be created by the Large Hadron Collider and the heaviest particles

which on theoretical grounds could exist without turning into black holes. So, there's a huge amount

of possible particles which could be out there as remnants of the Big Bang, but which we wouldn't

be able to detect so easily. So, the fact that we've got new constraints on what the doc matter

could be doesn't diminish my belief that it's there in the form of particles because we've only

explored a small fraction of parameter space. So, there's this search. You're literally, upon

unintended, are searching in the dark here in this giant parameter space of possible particles.

You're searching for, I mean, there could be all kinds of particles. There could be. And

there's some which may be very, very hard to detect. But I think we can hope for

some new theoretical ideas because one point which perhaps you'd like to discuss more is about the

very early stage of the Big Bang. And the situation now is that we have an outline picture for how the

universe has evolved from the time when it was expanding in just a nanosecond right up to the

present. And we could do that because after nanosecond, the physics of the material is in the same

range that we can test in the lab. After a nanosecond, the particles move around like those in the

large heterocollider. If you wait for one second, they're rather like in the centers of the hotter

stars and nuclear actions, please, hydrogen, helium, etc., which fit the data. So, we can with

confidence extrapolate back to when the universe was a nanosecond old. Indeed, I think we can do

it with as much confidence as anything a geologist tells you about the early history of the earth.

And that's huge progress in the last 50 years. But any progress puts in sharper focus new mysteries.

And of course, the new mysteries in this context are why is the universe expanding the way it is?

Why does it contain this mixture of atoms and dark matter and radiation? And why does it have

the properties which allow galaxies to form, being fairly smooth but not completely smooth?

And the answer to those questions are generally believed to lie in a much, much earlier stage

of the universe when conditions were much more extreme and therefore far beyond the stage where

we had the foot holding experiments, very theoretical. And so, we don't have a convincing theory. We

just have ideas until we have something like string theory or some other clues to the ultra

early universe that's going to remain speculative. So, there's a big gap. And to say how big the

gap is, if we take the observable universe, a bit more than 10 billion light years, then

when the universe was a nanosecond old, that would have been squeezed down to the size of our solar

system or compressed into that volume. But the times we're talking about when the key properties

of the universe were first imprinted were times when that entire universe was squeezed down to

the size of a tennis ball or baseball, if you prefer, and it emerged from something microscopic.

So, it's a huge extrapolation and it's not surprising that since it's so far from our

experimental range of detectability, we are still groping for ideas.

But you think first theory will reach into that place and then experiment will perhaps one day

catch up? Well, I think in a sense it's a combination. I think what we hope for is that

there'll be a theory which applies to the early universe, but which also has consequences which

we can test in our present day universe, like discovering my new treatise exists or things

like that. And that's the thing which, as I mentioned, we may perhaps need a bit of AI to

help us to calculate. But I think the hope would be that we will have a theory which

applies under the very, very extreme early stages of the universe, which gains credibility and

gains confidence because it also manages to account for otherwise unexplained features of

the no energy world and what people call a standard model of particle physics,

where there are lots of undetermined numbers. So, it may help with that.

So, we're dancing between physics and philosophy a little bit, but what do you think

happened before the Big Bang? So, this seems, this feels like something that's out of the

reach of science. It's out of the reach of present science because science develops and

as the front is advanced, then new problems come into focus that couldn't be postulated before.

I mean, if I think of my own career, when I was a student, the evidence for the Big Bang

was pretty weak, whereas now it's extremely strong. But we are now thinking about the

reason why the universe is the way it is and all that. So, I would put all these things we've

just mentioned in the category of speculative science and identity of bifurcation between that

and philosophy. But of course, to answer your question, if we do want to understand the very

early universe, then we've got to realize that it may involve even more counterintuitive concepts

than quantum theory does, because it's a condition even further away from everyday world

than quantum theory is and remember our lives, our brains evolved and haven't changed much since

our ancestors roamed the African savannah and looked at the everyday world. And it's rather

amazing that we've been able to make some sense of the quantum micro world and of the cosmos.

But there may be some things which are beyond us and certainly, as we implied,

there are things that we don't yet understand at all. And of course, one concept we might have

to jettison is the idea of three dimensions of space and time just ticking away. There are

lots of ideas. I mean, I think Stephen Hawking had an idea that talking about what's what hasn't

before the Big Bang, it's like asking what happens if you go north from the North Pole,

you know, it somehow closes off. That's just one idea. I don't like that idea, but that's a possible

one. And so we just don't know what happened at the very beginning of the Big Bang, were there

many Big Bangs rather than one, etc. And those are issues which we may be able to get some

foothold on from some new theory. But even then, we won't be able to directly test the theories.

But I think it's a heresy to think you have to be able to test every prediction of a theory.

Let me give another example. We take seriously what Einstein's theory says about the inside of

black holes, even though we can't observe them, because that theory has been vindicated in many

other places in cosmology and black holes, gravitational waves and all those things.

Likewise, if we had a theory which explains some things about the early history of our Big Bang

and the present universe, then we would take seriously the inference if it predicted many

Big Bangs, not one, even though we can't predict the other ones. So the example is that we can

take seriously a prediction if it's the consequence of a theory that we believe on other grounds.

We don't need to be able to detect another Big Bang in order to take it seriously.

It may not be a proof, but it's a good indication that this is the direction where the truth lies.

Yeah, if the theory is getting confidence in other ways.

Yes. Where do you sense? Do you think there's other universes besides our own?

There are well defined theories which make assumptions about the physics at the relevant

time. And this time, incidentally, is 10 to the power minus 36 seconds or earlier than that.

So this tiny sliver of time. And there are some theories, famous one due to Andre Linday,

the Russian cosmologist now at Stanford called eternal inflation, which did predict

an eternal production of new Big Bangs, as it were. And that's based on specific assumptions

about the physics. But those assumptions, of course, are just hypotheses which aren't vindicated.

But there are other theories which only predict one Big Bang. So I think we should be open minded

and not dogmatic about these options until we do understand the relevant physics.

But there are these different scenarios of very different ideas about this. But I think all of

them have the feature that physical reality is a lot more extensive than what we can see

through our telescope. I think even most conservator astronomers would say that because we can see out

with our telescopes to a sort of horizon, which is about, depending on how you measure it,

when maybe 15 billion light years away or something like that. But that horizon of our observations

is no more physical reality than the horizon around you, if you're in the ocean.

And looking out at your horizon, there's no reason to think that the ocean ends just beyond your

horizon. And likewise, there's no reason to think that the aftermath of our Big Bang

ends just at the boundary of what we can see. Indeed, there are quite strong arguments

that it probably goes on about 100 times further. It may even go on so much further

that all combinatorials are replicated. And there's another set of people like us sitting in a room

like this. Every possible combination of... Yeah, that could happen. That's not logically

impossible. But I think many people would accept that it does go on and contain probably a million

times as much stuff as what we can see within the horizon. The reason for that, incidentally,

is that if we look as far as we can in one direction and in the opposite direction,

then the conditions don't differ by more than one part in 100,000. So that means that if we're

apart of some finite structure, the gradient across the part we can see is very small. And so

that suggests that it probably does go on a lot further. And the best estimates say it must go

on at least 20 times further. Is that exciting or terrifying to you? Just the spans of it all,

the wide, everything that lies beyond the horizon. That example doesn't even hold for Earth. So it

goes way, way farther. And on top of that, just to take your metaphor further on the ocean,

while we're on top of this ocean, not only can we now see beyond the horizon,

we also don't know much about the depth of the ocean, nor the actual mechanism of observation

that's in our head. Yes. No, I think the Ruggles and the Housers is on those points you make.

Yes. But I think even the solar system is pretty vast by human standards. And so I don't think

the perception of this utterly vast cosmos need have any deeper impact on us than just

realizing that we are very small on the scale of the external world.

Yeah. It's humbling, though. It's humbling in depending where your ego is. It's humbling.

Well, if you start off very unhumble, indeed, it may make a difference. But most of us,

I don't think it makes much difference. And, well, there's a more general question, of course,

about whether the human race as such is something which is very special, or if, on the other hand,

it's just one of many such species elsewhere in the universe, or indeed existing at different

times in our universe. To me, it feels almost obvious that the universe should be full of alien

life, perhaps dead alien civilizations, but just the vastness of space. And it just feels wrong

to think of Earth as somehow special. It sure as heck doesn't look that special.

The more we learn, the less special it seems. Well, I mean, I don't agree with that as far as

life is concerned. Because remember that we don't understand how life began here on Earth.

And we don't understand, although we know there are any evolutions from simple life

to complex life, we don't understand what caused the transition between complex chemistry

and the first replicating metabolizing entity we call alive. That's a mystery.

And serious physicists and chemists are now thinking about it, but we don't know.

So we therefore can't say, was it a rare fluke which would not have happened anywhere else,

or was it something which involves a process that would have happened in any other

planet where conditions were like they were on the young Earth? So we can't say that now.

I think many of us would indeed bet that probably some kind of life exists elsewhere.

But even if you accept that, then there are many contingencies going from simple life to

present day life. And some biologists like Stephen Jay Gould thought that if you rerun

evolution, you'd end up with something quite different, and maybe not with an intelligent

species. So the contingencies in evolution may militate against the emergence of intelligence,

even if life gets started in lots of places. So I think these are still completely open questions.

And that's why it's such an exciting time now that we are starting to be able to address these.

I mean, I mentioned the fact that the origin of life is a question that we may be able to

understand. And serious people are working on it. It's usually put in the sort of too difficult

box. Everyone knew it was important, but they didn't know how to tackle it or what experiments

to do. But it's not like that now. And that's partly because of cleverer experiments. But I

think most importantly, because we are aware that we can look for life in other places,

other places in our solar system, and of course, on the exoplanets around other stars. And within

10 or 20 years, I think two things could happen, which will be really, really important. We might,

with the next big telescope, be able to image some of the Earth like planets around other stars.

Image, like get a picture. Well, actually, let me caveat that. It takes 50 years to get a resolved

image, but to actually detect the light. Because now, of course, these exoplanets are detected by

their effects on the parent star. They either cause their parent star to dim slightly when they

transit across in front of it. And so we see the dips, or their gravitational pull makes

the star wobble a bit. So most of the 5,000 plus planets that have been found around other stars,

they've been found indirectly by their effect in one of those two ways on the parent star.

You could still do a pretty good job of estimating size, all those kinds of things.

The size and the mass, you can estimate. But detecting the actual light

from one of these exoplanets hasn't really been done yet, except in one or two very

bright, big planets. Maybe like James Webb Telescope would be.

Well, James Webb may do this, but even better will be the European ground based telescope

called, on the magic of the Extremilars Telescope, which has a 39 meter diameter mirror.

39 meters is the equivalent of Jesus Glass. And that will collect enough light from

one of these exoplanets around the nearby star to be able to separate out its light

from that of the star, which is a million times brighter, and get the spectrum of the planet

and see if it's got oxygen or chlorophyll and things in it. So that will come.

James Webb may make some steps there. But I think we can look forward to learning quite a bit

in the next 20 years, because I like to say, supposing that we're aliens looking at the solar

system, then they'd see the Sun as an ordinary star, they'd see the Earth as in Carl Sager's

nice phrase, a pale blue dot. I'm very close in the sky to its star, our Sun, and much,

much, much fainter. But if they could observe that dot, they could learn quite a bit. They could

perhaps get the spectrum of the light and find the atmosphere. They'd find the shade of blue

was slightly different, depending on whether the Pacific Ocean or the land mass of Asia was

facing them, so they could infer the length of the day and the ocean and continents,

and maybe something about the seasons and the climate. And that's the kind of

calculation under inference we might be able to draw within the next 10 or 20 years

about other exoplanets. And evidence of some sort of biosphere on one of them would, of course,

be crucial, and it would rule out the still logical possibilities that life is unique.

But there's another way in which this may happen in the next 20 years. People think there could be

something swimming under the ice of Europa and then Celadus and probes are being sent to maybe

not quite go under the ice, but detect the spray coming out to see if there's evidence for

organics in that. And if we found any evidence for an origin of life that happened

in either of those places, that would immediately be important, because if

life has originated twice independently in one planetary system, the solar system,

that would tell us straight away it wasn't a rare accident and must have happened

billions of times in the galaxy. At the moment, we can't rule out it being unique. And incidentally,

if we found life on Mars, then that would still be ambiguous because

people have realized that this early life could have got from Mars to Earth or vice versa on

meteorites. So if you found life on Mars, then some skeptics could still say if it was a single

origin. But I think Europe is far enough. That's far enough away. That's why that would be especially.

It's always the skeptics that ruin a good party. But we need them, of course.

We need them at the party. We need some skeptics at the party. But boy, would that be so exciting

to find life on one of the moons, because it means that life is everywhere.

That'll just be any kind of vegetation or life. The question of the aliens of science fiction

is a different matter. Intelligent aliens. But if you have a good indication that there's life

elsewhere in the solar system, that means life is everywhere. I don't know if that's terrifying

or what that is, because if life is everywhere, why is intelligent life not everywhere? You've

talked about that most likely alien civilizations, if they are out there, they would likely be far

ahead of us, the ones that would actually communicate with us. And that, again, one of those things

that is both exciting and terrifying. You've mentioned that they're likely not to be of biological

nature. Well, I think that's important. Of course, again, it's a speculation, but in speculating about

intelligent life. And I take the search seriously. In fact, I chair the committee that the Russian

American investor Yuri Milner supports looking for intelligent life. He's putting $10 million

a year into better equipment and getting time on telescopes to do this. And so I think it's

worthwhile, even though I don't hold my breath for success. It's very exciting. But that does

lead me to wonder what might be detected. And I think, well, we don't know. We've got to be

mindful about anything. We've no idea what it will be. And so any anomalous objects,

or even some strange shiny objects in the solar system or anything, we've got to keep our eyes

open for. But I think if we ask what about a planet like the Earth where evolution had taken

more of the same track, then as you say, it wouldn't be synchronized. If it had lagged behind,

then of course, it would not have got to advanced life. But it may have had a head start. It may

have formed on a planet around an older star. But then let's ask what we would see. It's taken

nearly four billion years from the first life to us. And we've now got this technological

civilization, which could make itself detectable to any alien life, aliens out there. But I think

most people would say that this civilization of flesh and blood creatures in the collective

civilization may not last more than a few hundred years more. I think that the bad people may,

some people would say it will kill itself off. But I'm more optimistic. And I would say

that what we're going to have in future is no longer the slow Darwinian selection,

but we're going to have what I call secular intelligence design, which will be humans designing

their progeny to be better adapted to where they are. And if they go to Mars or somewhere,

they're badly adapted, they want to adapt a lot. And so they will adapt. But there may be some

limits to what could be done with flesh and blood. And so they may become largely electronic,

download their brains and be electronic entities. And if they're electronic,

then what's important is that they're near immortal. And also, they won't necessarily want to be on a

planet with an atmosphere or gravity. They may go off into the blue yonder. And if they're near

immortal, they won't be daunted by interstellar travel taking a long time. And so if we looked

at what would happen on the earth in the next millions of years, then there may be these

electronic entities which have been sent out and are now far away from the earth,

but still sort of burping away in some fashion to be detected. And so this therefore leads me to

think that if there was another planet which had evolved like the earth and was ahead of us,

it wouldn't be synchronized. So we wouldn't see a flesh and blood civilization,

but we would see these electronic progeny as it were. And then this raises another question,

because there's the famous argument against there being lots of aliens out there, which is that they

would come and invade us and eat us or something like that. That's a common idea, which is fairly

is attributed to have been the first to say. And I think there's a escape clause to that because

these entities would be evolved by second intelligence design, designed by their predecessors

and then designed by us. Whereas Darwinian selection requires two things. It requires

aggression and intelligence. This future intel design may favor intelligence because that's

what they were designed for, but it may not favor aggression. And so these future entities, they

may be sitting deep thoughts, thinking deep thoughts and not being a tall expansionist. So

they could be out there. And we can't refute their existence in the way the Fermi paradox is

supposed to refute their existence because these would not be aggressive or expansionist.

Well, maybe evolution requires competition, not aggression. And I wonder if competition can take

forms that are non expansionary. So you can still have fun competing in the space of ideas,

which may be primarily philosophical, perhaps, in a way, right. It's an intellectual exercise

versus a sort of violent exercise. So what does this civilization on Mars look like? So do you

think we would more and more, you know, maybe start with some genetic modification and then

move to basically cyborgs, increasing integration of electronic systems, computational systems

into our bodies and brains? This is a theme of my other new book out this year, which is called

The End of Astronauts and co co written with my own friend and colleague from Berkeley,

Don Goldsmith. And it's really about the role of human spaceflight versus sort of robotic

spaceflight. And just to summarize what it says, it argues that the practical case for sending

humans into space is getting weaker all the time as robots get better and more capable.

Robots 50 years ago couldn't do anything very much. But now they could assemble big structures on

space or in space or on the moon, and they could probably do exploration. Well, present ones on

Mars can't actually do the geology, but future AI will be able to do the geology and already they

can dig on Mars. And so if you want to do exploration of Mars, and of course, even more of

Enceladus or Europa where you could never send humans, we depend on robots. And they're far,

far cheaper because to send a human to Mars requires feeding them for 200 days on the journey

there and bringing them back and neither of those are necessary for robots. So the practical case

for humans is getting very, very weak. And if humans go, it's only as an adventure, really.

And so the line in our book is that human spaceflight should not be pursued by NASA or public

funding agencies because it has no practical purpose, but also because it's especially

expensive if they do it because they would have to be risk averse in launching civilians into space.

I can illustrate that by noting that the shuttle was launched 135 times and it had two spectacular

failures, which each killed the seven people in the crew. And it had been mistakenly presented as

safe for civilians. And there was a woman's school teacher killed in one of them. It was a big

national trauma and they tried to make it safer still. But if you launch into space just the

kind of people prepared to accept that sort of risk, and of course test pilots and people who go

hang gliding and go to the South Pole, etc., are prepared to accept a 2% risk at least for a big

challenge, then of course you do it more cheaply. And that's why I think human spaceflight should

be left to the billionaires and their sponsors because then the taxpayers aren't paying and they

can launch simply those people who are prepared to accept high risks, space adventure, not space

tourism. And we should cheer them on. And as regards where they would go, then low earth orbit,

I suspect, can be done quite cheaply in the future. But going to Mars, which is very, very expensive

and dangerous for humans, the only people who would go would be these adventurers, maybe on one way

trip like some of the early polar explorers and Magellan and people like that, and we would cheer

them on. And I expect and I very much hope that by the end of the century there will be a small

community of such people on Mars living far less comfortably than at the South Pole or the bottom

of the ocean or the top of Everest, but they will be there and they won't have a return ticket,

but they'll be there. Incidentally, I think it's a dangerous illusion to think, as Elon Musk has

said, that we can have mass emigration from the earth to Mars to escape the earth's problems.

It's a dangerous illusion because it's far easier to deal with climate change on earth

than to terraform Mars to make it properly habitable to humans. So there's no planet

beef or ordinary risk of earth people. But for these crazy adventurers, then you can imagine

that they would be trying to live on Mars as great pioneers. And by the end of the century,

then there will be huge advances compared to the present in two things. First in understanding

genetics, so is to genetically redesign one's offspring. And secondly, to use cyborg techniques

to implant something in our brain or indeed think about downloading, etc. And those techniques will,

one hopes, be heavily regulated on earth, on potentials and ethical grounds. And of course,

we are pretty well adapted to the earth, so we don't have the incentive to do these things in

the way they were there. So our argument is that it'll be those crazy pioneers on Mars

using all these scientific advances, which would be controlled here, away from the regulators,

they will transition into a new post human species. And so if they do that, and if they

transition into something which is electronic, eventually, because there may be some limits

to the capacity of flesh and blood brains, anyway, then those electronic entities may not

want to stay on a planet like Mars, they may want to go go away. And so they'll be the precursors

of the future evolution of life and intelligence coming from the earth. And of course, there's

one point which perhaps astronomers are more aware of than most people. Most people are aware

that we are the outcome of four billion years of evolution. Most of them, nonetheless, probably

think that we humans are somehow the culmination, the top of the tree. But yes, no astronomers

can believe that because astronomers know that the earth is four and a half billion years old.

The sun has been shiny for that length of time, but the sun has got six billion years more to go

before it flares up and engulfs the inner planet. So the sun is less than halfway through its life.

And the expanding universe goes on far longer still, maybe forever. And I like to quote Woody Allen,

who said eternally is very long, especially towards the end. So we shouldn't think of ourselves as

maybe even a halfway stage in the emergence of cosmic complexity. And so these entities who are

post curses, they will go beyond the solar system. And of course, even if there's nothing else out

there already, then they could populate the rest of the galaxy. And maybe eventually meet the others

who are out there expanding as well, expanding and populating with expanded capacity for life

and intelligence, all those kinds of things. Well, they might, but again, all better off.

Because I can't conceive what they'd be like. They won't be green men and women with eyes on

stalks. They'd be something quite different. We just don't know. But there isn't anything

to question, actually, which comes up when I've sometimes spoken to audiences about this topic,

but the question of consciousness and self awareness. Because going back to philosophical

questions, whether an electronic robot would be a zombie, or would it be conscious and self aware?

And I think there's no way of answering this empirically. And some people think that consciousness

and self awareness is an emergent property in any sufficiently complicated networks that they

would be. Others say, well, maybe it's something special to the flesh and blood that we're made

of. We don't know. And in a sense, this may not matter to the way things behave, because they

could be zombies and still behave as though they were intelligent. But I remember after

one of my talks, someone came up and said, wouldn't it be sad if these future entities,

which were the main television universe, had no self awareness? So there was nothing

which could appreciate the wonder and mystery of the universe, and the beauty of the universe,

in the way that we do. And so it does perhaps affect one's perspective of whether you welcome

or deplore this possible future scenario, depending on whether you think the future

post human entities are conscious and have an aesthetic sense, or whether they're just zombies.

And of course, you have to be humble to realize that self awareness may not be the highest form

of being, that humans have a very strong ego and a very strong sense of identity,

like personal identity connected to this particular brain. It's not so obvious to me that that is

somehow the highest achievement of a life form, that maybe this kind of collective would be.

It's possible that, well, I think from an alien perspective, when you look at earth,

it's not so obvious to me that individual humans are the atoms of intelligence. It could be the

entire organism together, the collective intelligence. And so we humans think of ourselves

as individuals, we dress up, we wear ties and suits, and we'll give each other prizes. But in

reality, the intelligence, the things we create that are beautiful emerges from our interaction

with each other. And that may be where the intelligence is, ideas jumping from one person

to another over generations. Yes, but we have experiences where we can appreciate beauty and

wonder and all that. And a zombie may not have those experiences. Yeah, or it may have a very

different, they have a very black and white harsh description of like a philosophical zombie,

a zombie, that could be just a very different way to experience.

And, you know, in terms of the explorers that colonize Mars, I mean, there's several things

I want to mention. One, it's just at a high level to me, that's one of the most inspiring

things humans can do is reach out into the unknown. That's in the space of ideas,

in the space of science, but also the explorers. And that inspires people here on Earth more.

I mean, it did in their, you know, when going to the moon or going out to space in the 20th

century, that inspired a generation of scientists. I think that also could be used to inspire a

generation of new scientists in the 21st century by reaching out towards Mars. So in that sense,

I think what Elon Musk and others are doing is actually quite inspiring. It's not,

it's not a recreational thing. It's actually has a deep humanitarian purpose of really inspiring

the world. And then on the other one, to push back on your thought, you know, I don't think Elon says

we want to escape Earth's problems. It's more that we should allocate some small percentage

of resources to have a backup plan. And because you yourself have spoken about and written about

all the ways we clever humans can destroy ourselves. And I'm not sure it does seem,

when you look at the long arc of human history, it seems almost obvious that we need to become

multi planetary species over a period. If we are to survive many centuries, it seems that

as we get clever and clever with the ways we can destroy ourselves, Earth is going to become less

than less safe. So in that sense, this is one of the things, you know, people talk about climate

change, and then we need to respond to climate change. And that's a long term investment we need

to make. But it's not really long term, it's a span of decades. I think what Elon is doing is

a really long term investment. We should be working on multi planetary colonization now,

if we were to have it ready five centuries from now. And so taking those early steps.

And then also, there's something happens when you're caught when you

go into the unknown and do this really difficult thing, you discover something very new,

you discover something about robotics or materials engineering, or nutrition,

or neuroscience or human relations or political systems that actually work well with humans.

You discover all those things. And so it's a worthy effort to go out there and try to become

cyborgs. Yeah, no, I agree with that. I think the only different point I'd make is that

this is going to be very expensive, if it's done in a risk averse way. And that's why I think we

should be grateful to the billionaires, if they're going to sort of foster these opportunities

for thrill seeking risk takers who we can all admire.

Yeah. By the way, I should push back on the billionaires, because there's sometimes a

negative connotation to the word billionaire. It's not a billionaire, it's a company versus

government, because governments are billionaires and trillionaires. It's not the wealth, it's the

capitalist imperative, which I think deserves a lot more praise than people are giving it.

I'm troubled by the sort of criticism like it's billionaires playing with toys for their own

pleasure. I think what some of these companies like SpaceX and Blue Origin are doing is some

of the most inspiring engineering and even scientific work ever done in human history.

No, I agree. I think the people who've made the greatest wealth are people who've really been

mega benefactors. I mean, I think some of them, some of them.

Yes, some of them, but those who've founded Google and all that and even Amazon,

they're beneficiaries. They're in a quite different category, in my view,

from those who just shuffle around money or crypto coins and things like that.

But now you're really talking trash.

Yes, but I think if they use their money in these ways, that's fine, but I think it's

true that the far more money is owned by us collectively as taxpayers, but I think the

fact is that in a democracy, there'd be big resistance to exposing human beings to very high

risks, if in a sense we share responsibility for it. That's the reason I think we've done much

more cheaply by these private funders. That's an interesting hypothesis,

but I have to push back. I don't know if it's obvious why NASA spends so much money and takes

such a long time to develop the things it was doing. Before Elon Musk came along,

because I would love to live in a world where government actually uses taxpayer money to get

some of the best engineers and scientists in the world and actually work across governments,

Russia, China, United States, the European Union together to do some of these big projects,

it's strange that Elon is able to do this much cheaper, much faster. It could have to be

due with risk aversion, you're right. I think it's that is that he had all the whole assembly

within this one building as it were rather than depending on a supply chain, but I think it's

also that he had a Silicon Valley culture and had younger people, whereas the big aerospace

companies, Boeing and Lockheed Martin, they had people who were left over from the Apollo program

in some cases, and so they weren't quite so lively. Indeed, quite apart from the controversial issues

of the future of human spaceflight, in terms of the next generation of big rockets, then the one

that Musk is going to launch for the first time this year, the huge one, is going to be far,

far cheaper than the one that NASA's been working on at the same time, and that's because it will

have a reusable first stage, and it's going to be great. It can launch over 100 tons into Earth orbit,

and it's going to be make it feasible to do things that I used to think were crazy,

like having solar energy from space. There's no longer so crazy if you can do that, and also

for science, because its nose cone could contain within it something as big as the entire unfurled

James Webb telescope mirror, and therefore you can have a big telescope much more cheaply if you

can launch it all in one piece, and so it's going to be hugely beneficial to science and to any

practical use of space to have these cheaper rockets that are far more completely reusable

than it was NASA had, so I think Musk's are a tremendous service to space exploration and

the whole space technology through these rockets, certainly. Plus, it's some big sexy rocket,

it's just great engineering. Of course, yeah. It's like looking at a beautiful big bridge

that humans are capable, us descendants of apes are capable to do something so majestic.

Yes, and also the way they land coming down this bar, that's amazing. It's both controls,

engineering, it's increasing intelligence in these rockets, but also great propulsion

engineering materials, entrepreneurship, and it just inspires so many people.

No, I'm entirely with you on that.

So would it be exciting to you to see a human being step foot on Mars in your lifetime?

Yes, I think it's unlikely in my lifetime since I'm so ancient, but I think this century is going

to happen and I think that will indeed be exciting and I hope there will be a small

community by the end of a century. But as I say, I think they may go with one way tickets or

accepting the risk of no return. So they've got to be people like that and I still think it's going

to be hard to persuade the public to send people when you say straight out that they may never

come back. But of course the Apollo astronauts, they took a high risk and in fact in my previous

book I quote the speech that's been written for Nixon to be read out if Neil Armstrong got stuck

on the moon. And it was written by one of his advisors and very eloquent speech about

how they have come to a noble end, etc. But of course there was a genuine risk at that time.

But that may have been accepted, but clearly the crashes of the shuttle were not acceptable to the

American public even when they were told that this was only a 2% risk given how often they

launched it. And so that's what leads me to think that it's got to be left to the kind of

people who are prepared to take these risks. And I think of a mega adventure was a guy called

Steve Fossa, who was an aviator, did all kinds of crazy things, you know, and then a guy who fell

supersonicly with the parachute from very high altitude. All these people, we all share them on.

They extend the bounds of humanity. But I don't think the public will be so happy to fund them.

I mean, I disagree with that. I think if we change the narrative, we should change the story.

You think so?

I think there's a lot of people, because the public is happy to fund

folks in other domains that take bold, giant risks. First of all, military, for example.

Military, obviously, yes. I think this is in the name of science, especially if it's

sold correctly, I sure as hell would go up there with a risk. I would take a 40% chance risk of

death for something that's... I might want to be even older than them now, but then I would go.

I guess what I'm trying to communicate is there's a lot of people on earth that's the nice feature,

and I'm sure there's going to be a significant percentage or some percentage of people that

are... They take on the risk for the adventure. I particularly love that risk of adventure when

taking on inspires people, and just the ripple effect that has across the generation, especially

among the young minds, is perhaps immeasurable. But you're thinking that sending humans should

be something we do less and less, sending humans to space, that it should be primarily an effort...

The work of space exploration should be done primarily by robots.

Well, I think it can be done much more cheaply, obviously, on Mars, and no one's thinking of

sending humans to Enceladus or Europa, the outer planets. And the point is we'll have much better

robots, because let's take an example. You've seen the pictures of the moons of Saturn and the picture

of Pluto and the comet taken by probes and Cassini spent 13 years going around Saturn and its moons

after a seven year voyage. And those are all based on 1990s technology. And if you think of how

smartphones have advanced in 20 years since then, just think how much better one could do, instrumenting

some very small sophisticated probe that could send dozens of them to explore the outer planets.

And that's the way to do that, because no one thinks you could send humans that far.

And I would apply the same argument to Mars. And if you want to assemble big structures like,

for instance, radio astronomers would like to have a big radio telescope on the far side of

the moon, so it's away from the Earth's background artificial radio waves. And that could be done

by assembling, using robots without people. So on the moon and on Mars, I think everything that's

useful can be done by machines much more cheaply than by humans. Do you know the movie 2001,

A Space Odyssey? Of course, yes. But you must be too young to have seen that when it came out,

obviously. I remember seeing it when it came out. You saw it when it came out.

Yeah, yeah, 50 years ago. 60, when was it? 60? In the 60s? Yeah, it's still classic.

It's still probably, for me, the greatest AI movie ever made. Yes, yes, I agree. One of the great

space movies ever made. So let me ask you a philosophical question since we're talking

about robots exploring space. Do you think how 9000 is good or bad? So for people who haven't

watched, this computer system makes a decision to basically prioritize the mission that the ship is

on over the humans that are part of the mission. Do you think how is good or evil?

If you ask me, probably in that context, it was probably good. But I think you're raising

what is, of course, very much an active issue in everyday life about the extent to which we should

entrust any important decision to a machine. And there again, I'm very worried because I think

if you are recommended for an operation or not given parole from prison, or even denied credit

by your bank, you feel you should be entitled to an explanation. It's not enough to be told that the

machine has a more reliable record on the whole than humans have of making these decisions. You

think you should be given reasons you could understand. And that's why I think the presence

of subtle trends to take away the humans and leave us in the hands of decisions that we can't contest

is a very dangerous one. I think we've got to be very careful of the extent to which AI,

which can handle lots of information, actually makes the decisions without oversight. And I think

we can use them as a supplement, but to take the case of radiology and cancer. I mean,

it's true that the radiologist hasn't seen as many x ways of cancer lungs as the machine.

So the machine can certainly help, but you want the human to make the final decision. And I think

that's true in most of these instances. But if we turn a bit to the short term concerns with robotics,

I think the big worry, of course, is the effect it has on people's self respect and their labor

market. And I think my solution will be that we should arrange to tax more heavily the big

international conglomerates, which use the robots and use that tax to fund

decently paid dignified posts of the kind where being a human being is important. Above all,

carers for old people, teachers, assistants for young, gardeners in public parks and things like

that. And if the people who are now working in mind numbing jobs in Amazon warehouses

or in telephone call centers are automated, but those same people are given jobs where being a

human is an asset, then that's a plus plus situation. And so that's the way I think that we

should benefit from these technologies, take over the mind numbing jobs and use machines to

make them more efficient, but enable the people so displaced to do jobs where we do want human

being. I mean, most people when they're old, the rich people, if they have the choice,

they want human carers and all that, don't they? They may want robots to help with some things,

MC to bedpans and things like that, but they want real people. And certainly in this country,

I think even worse in America, the care of old people is completely inadequate and it needs

just more human beings to help them cope with everyday life and look after them when they're

sick. And so that seems to me the way in which the money raised in tax from these big companies

should be deployed. So that's in the short term. But if you actually just look, the fact is where

we are today to long term future in 100 years, it does seem that there is some significant chance

that the human species is coming to an end in its pure biological form. There's going to be

greater and greater integration to genetic modification than cyborg type of creatures.

And so you have to think, all right, well, we're going to have to get from here to there.

And that process is going to be painful. And that, you know, how there's so many different

trajectories that take us from one place to another, it does seem that we need to deeply respect

humaneness and humanity, basic human rights, human welfare, like happiness and all that kind

of stuff. No, absolutely. And that's why I think we ought to try and slow down the application of

these human enhancement techniques and cyborg techniques for humans for just that reason.

I mean, that's why I want to lead into the people on Mars. Let them do it. But there are people too.

Okay. People on Mars are people too. I tend to, you know, but they are very poorly adapted to

where they are. That's why they need modification, whereas we're adapted to the earth quite well.

So we don't need these modifications. We're happy to be humans living in the environment

where our ancestors lived. So we don't have the same motive. So I think there's a difference.

But I agree, we don't want drastic changes probably in our lifestyle. And that indeed is a worry

because some things are changing so fast. But I think I'd like to inject a note of caution.

If you think of the way programs in one technology goes, it goes in a sort of

spurt. It goes up very fast and then it levels off. Let me give you two examples of one we've

had already, a human space flight at the time of the Apollo program. It was only 12 years after

Sputnik 1. I was alive then and I thought it would only be 10 or 20 years further before

the Earth would pretend Mars. But as we know, for reasons we could all understand, that was,

and still remains the high point of human space exploration. And that's because it was funded for

reason to superpower rivalry at huge public expense. But let me give you another case,

civil aviation. If you think of the change between 1919 when that was Alcock and Brown's

first transatlantic fight to 1979, the first flight to the jumbo jet was a big change.

It's more than 50 years since 1969. And we still have jumbo jets more or less the same. So that's

an example of something which developed fast and to take another analogy, we've had huge

developments in mobile phones. But I suspect the iPhone 24 may not be too different from

the iPhone 13. They develop, but then they saturate and then maybe some new innovation

takes over in stimulating economic growth. Yeah, so it's that we have to be cautious about being

too optimistic. And we have to be cautious about being too cynical. I think that is well, optimistic

is begging the question. I mean, do we want this very rough a change? Right. So first of all,

there's some degree to which technological advancement is something is a force that can't

be stopped. And so the question is about directing it versus stopping it or slowing it can be sort

of slot to slow what they human spaceflight that could be have been footprints on Mars if and if

America gone on spending 4% of the federal budget on the project after. Yes, by the reason. So it's

very good reasons, but and we could we could have had supersonic flight, but Concorde came

and went during the 50 years. But the reason it didn't progress is not because we realize it's not

good for human society. The reason it didn't progress is because it couldn't make sort of from

a capitalist perspective, it couldn't make there was no short term or long term way for it to make

money. So for me, but that's the same as saying it's local for society. I don't think everything

that makes money is good for society and everything that doesn't make money is bad for society,

right? That's a that's a difficult, that's a difficult thing we're always contending with

when we look at social networks. It's not obvious even though they make a tremendous amount of money

that they're good for society, especially how they're currently implemented with the advertisement

and engagement maximization. So that's the constant struggle of you know, I agree with you

that many innovations are damaging. Yes. Yes. Well, but I would have thought that supersonic

flight was something that would benefit only a tiny elite, huge expense and environmental damage.

That was obviously something which they're very glad not to have in my opinion.

Yeah. But perhaps there was a way to do it where it could benefit the general populace. If you were

to think about airplanes, wouldn't you think that in the early days, airplanes would have been seen

as something that can surely only benefit 1% at most of the population as opposed to a much

larger percentage. There's another aspect of capitalist system that's able to drive down

costs once you get the thing kind of going. So, you know, we get together maybe with taxpayer

money and get the thing going at first. And once it gets going, companies step up and drive down

the cost and actually make it so that blue collar folks can actually start using this. Yeah. Sometimes

that does happen. That's good. Yeah. So, that's again the double S sword of human civilization

that some technology hurts us, some benefits us and we don't know ahead of time. We could just

do our best. There's a gap between what could be done and what we can actually decide to do.

Yes. In the term, you could push forward some developments faster than we do.

Let me ask you, in your book on the future prospects for humanity,

you imagine a time machine that allows you to send a tweet length message to scientists in the past

like the Newton. Yes. What tweet would you send? It's an interesting thought experiment. What

message would you send to Newton about what we know today? Well, I think he'd love to know

that there were planets around all the stars. He'd like to know that that would really blows

mind. He'd like to know that everything was made of atoms. He'd like to know that if he looked a

bit more carefully through his prisms and looked at light not just from the sun, but from some

flames, he might get the idea that different substances emitted light of different colors

and he might have been twigged to discover some things that had to wait 200, 300 years.

Could have given him those clues, I think. It's fascinating to think, to look back

at how little he understood, people at that time understood about our world.

Yes. And certainly about the cosmos, because of course, well, if we think about astronomy,

then until about 1850, astronomy was a matter of the positions of how the stars and the planets

moved around. Of course, that goes back a long way, but Newton understood why the planets moved

around in ellipses. But he didn't understand why the solar system was all in a plane, what we

call the ecliptic. And he didn't understand it. He didn't know what until the mid 19th century

what the stars are made of. We thought we made it some fifth essence, not earth, earth,

and water like everything else. And it was only after 1850 when people did use prisms

more precisely to get spectra that they realized that the sun was made of the same

stuff as the earth, and indeed the stars were. And it wasn't until 1930 that people

knew about nuclear energy and knew what kept the sun shining for so long. So it was quite late

that some of these key ideas came in, which would have completely transformed Newton's views,

and of course, the entire scale of the galaxy and the rest of the universe.

Just imagine what he would have thought about the Big Bang, or even just general relativity.

Him and Einstein talking for a couple of weeks. Would he be able to make sense of spacetime

and the curvature of spacetime? Well, I think given a quick course, I mean, he was sort of,

if one looks back, he was really a unique intellect in a way. And he said that he

thought better than everyone else by thinking on things continually and thinking very deep

thoughts. And so he was an utterly remarkable intellect, obviously. But of course, scientists

aren't all like that. I think it's one thing that's interesting to me, having spent a life

amongst scientists is what a variety of mindsets and mental styles they have. And well, just to

contrast Newton and Darwin, Darwin said, and he's probably correct, that he thought he just had

as much sort of a common sense and reasoning power as he had with his lawyer. And that's probably

true because his ability was to sort of connect data and think through things deeply. That's

a quite different kind of thinking from what was involved in Newton or someone doing abstract

mathematics. I think in the 20th century, the coolest, well, there's the theory, but

from an astronomy perspective, black holes is one of the most fascinating entities to have been

through theory and through experiment to have emerged from.

Obviously, I agree. It's an amazing story that, well, of course, what's interesting is Einstein's

reaction because, as you know, we now accept this is one of the most remarkable predictions of

Einstein's theory. He never took it seriously, even believed it. Although it was a consequence of

a series of his equations, which someone discovered just a year off his theory, Swordsfield,

but he never took it seriously and others did. But then, of course, well, this is something

that I've been involved in, actually finding evidence for black holes. And that's come in

the last 50 years. And so now there's pretty compelling evidence that they exist as the

remnants of stars or big ones in the center of galaxies. And we understand what's going on.

We have ideas vaguely on how they form. And, of course, gravitation waves have been detected.

And that's an amazing piece of technology.

LIGO is one of the most incredible engineering efforts of all time.

That's an example where the engineers deserve the most of the credit because the precision is,

as they said, it's like measuring the thickness of a hair at the distance of Alpha Centauri.

Yeah, it's incredible.

Tens of miles 21.

So maybe actually, if we step back, what are black holes? What do we humans understand about

black holes? And what's still unknown?

Einstein's theory, extended by people like Roger Penrose, tells us that black holes are,

in a sense, one of the simple things, basically, because they are solutions to Einstein's equations.

And the thing that was shown in the 1960s by Roger Penrose in particular, and by a few other people,

was that a black hole, when it forms and settles down, is defined just by two quantities. It's

mass and it's spin. So they're actually based standardized objects. It's amazing that objects

as standardized as that can be so big and can lurk in the vessel solar system. And so that's

the situation for a ready formed black hole. But the way they form, obviously, is very messy and

complicated. And one of the things that I've worked on a lot is what the phenomena are,

which are best attributed to black holes and what may lead to them and all that.

Which, can you explain to that? So what are the different phenomena that lead to a black hole?

Let's talk about it. This is so cool.

Okay. Well, I mean, I think one thing that only became understood really in the 1950s, I suppose,

and beyond was how stars evolve differently depending on how heavy they are. This is the sun

burns hydrogen to helium. And then when it's run out of that, it contracts to be a white dwarf.

And we know how long that will take, say about 10 billion years altogether for its lifetime.

But big stars burn up their fuel more quickly and more interestingly, because when they've

turned hydrogen to helium, they then get even hotter. So they confuse helium into carbon

and go up the periodic table. And then they eventually explode when they have an energy crisis

and they blow out that process material, which as a digression is crucially important because

all the atoms inside our bodies were synthesized inside a star, a star that lived and died more

than 5 billion years ago before our services informed. And so we each have inside us atoms made

in thousands of different stars all over the Milky Way. And that's an amazing idea. And my

predecessor Fred Hoyle in 1946 was the first person to suggest that idea. And that's been

borne out. That's a wonderful idea. So that's how massive stars explode. And they leave behind

something which is very exotic and of two kinds. One possibility is a neutron star.

And these were first discovered in 1967, 68. These are stars a bit heavier than the sun,

which are compressed to an amazing density. So the whole mass of more than the sun's mass

is in something about 10 miles across. So they're extraordinarily dense. They're exotic physics.

And they've been studied in immense detail. And they've been real laboratories because the good

thing about astronomy, apart from exploring what's out there, is to use the fact that the

cosmos has provided us with a lab with far more extreme conditions than we could ever

simulate. And so we learn lots of basic physics from looking at these objects. And that's been

true of neutron stars. But for black holes, that's even more true because the bigger stars,

when they collapse, they leave something behind in the center, which is too big to be a stable white

two or four neutron star becomes a black hole. And we know that there are lots of black holes weighing

about 10 or up to 50 times as much as the sun, which are the remnants of stars. They were detected

first 50 years ago, when a black hole was orbiting around another star and grabbing

material from the other star, which swirled into it and gave us X ray. So the X rays astronomers

found these objects orbiting around an ordinary star and emitting X ray radiation very intensely,

varying out of a short time scale. So something very small and dense was giving that radiation.

That was the first evidence for black holes. But then the other thing that's happened was

realizing that there was a different class of monster black holes in the center of galaxies.

And these are a response for what's called quasars, which is when

something in the center of a galaxy is grabbing some fuel and outshines all the

100 billion stars or so in the rest of the galaxy. A giant beam of light. And in many

cases, it should be, it should be. Is that that's gotta be the most epic thing the universe produces

quasars? Well, it's a debate about the most epic, but quasars maybe or maybe gamma ray bursts or

something. But they are remarkable. And they were a mystery for a long time. And they're

one of the things I worked on in my younger days. So even though they're so bright, they're still

a mystery. And I wouldn't say they're a little mystery now. I think we do understand basically

what's going on. How were quasars discovered? Well, they were discovered when astronomers

found things that looked like stars and they were small enough to be a point like and not resolved

by a telescope, but outshone an entire galaxy. Yeah. And that's suspicious. Yes. But then they

realized that what they were, they were object which you now know are black holes. And they were

black holes were capturing gas. And that gas was getting very hot. But it was producing

far more energy than all the stars added together. And it was the energy of the

black hole that was lighting up all the gas in the galaxy. So you've got a spectrum of it.

So this was something which was realized from 1970s onwards. And as you say, the other thing

we've learned is that they often do produce these jets squirting out, which could be detected in

in all wave bands. So there's now a picture black hole generating jets like the center of most

galaxies. Do we know? Do we have a sense if every galaxy has one of these big, big boys?

Well, most galaxies have big black holes. They vary in size. The one in our galactic center.

Do we know much about ours? We do, yes. We know it weighs about as much as four million

suns, which is less than some, it's a several billion other galaxies. And but we know this

the one in our galactic center isn't very bright or conspicuous. And that's because not much is

falling into it at the moment. If a black hole is isolated, then of course it doesn't radiate. It only

all that radiates is gas swirling into it, which is very hot or has magnetic fields.

It's only radiating the thing it's murdering or consuming or however you put it.

Yeah, that's right. And so it's thought that our galaxy may have been bright,

bright at some time in the past. But now, and that's when the black hole formed or grew. But

now it's not catching very much gas. And so it's rather it's rather faint and detected indirectly

and by fairly weak radio emission. And so I think the answer to your question is that

we suspect that most galaxies have a black hole in them. So that means that some stays in their

lives, or maybe one or more stages, they went through a phase of being like a quasar where

that black hole captured gas and became very, very bright. But for the rest of the lives,

the black holes are fairly quiescent because there's not much gas falling into them.

And so this universe of ours sprinkled a bunch of galaxies and giant black holes with

like very large number of stars orbiting these black holes and then planets orbiting.

And that's right. And just this beautiful universe of ours. So what happens when galaxies collide,

when these two big black holes collide? Is that? Yes. Well, what would happen is that well,

and I should say that this is going to happen near us one day, but not for four billion years,

because the Andromeda galaxy, which is the biggest scan of the galaxy,

is going to be the biggest scan of the galaxy. And it's going to be the biggest scan of the galaxy.

Four billion years, because the Andromeda galaxy, which is the biggest galaxy near to us, which is

about three million light years away, which is a big disk galaxy with a black hole in its hub,

rather like our Milky Way. And that's in falling towards us because they're both in a

common gravitational potential well. And that will collide with our galaxy in about four billion

years. But it'll be maybe it'll be a lesser collision and more of a dance because it'll be

like a swirling situation. Well, it's a swirling, but eventually there'll be a merger. They'll

go through each other and then merge. In fact, the nice move is to be made of this computer

simulations and it'll go through. And then there's a black hole in the sense of Andromeda and our

galaxy. And the black holes will settle towards the center. Then they will orbit around each other

very fast and then they will eventually merge. And that will produce a big burst of gravitational

waves, a very big burst. That an alien civilization with a LIGO like detector will be able to detect.

Yes. Well, in fact, we can detect these with their lower frequencies than the

ways that have been detected by LIGO. So there's a space interferometer which can detect these.

It's about one cycle per hour rather than about a hundred cycles per second. Yes.

It's the ones that are detected. But that will happen. But thinking back to what will happen

in four billion years to any of our descendants, they'll be okay because the two disk galaxies

will merge. It'll end up as a sort of amorphous elliptical galaxy. But the stars won't be much

closer together than they are now. It'll still be just twice as many stars in the structure,

almost as big. And so the chance of another star colliding with our sun would still be very small.

Yeah. Because there's actually a lot of space between stars and planets.

Yes. The chance of a star getting close enough to affect our solar systems orbit

is small and it won't change that very much. So you can be reassured.

A heck of a starry sky though. What would that look like?

Well, it won't make much difference even to that actually. It'll just be...

Wouldn't that look kind of beautiful when you're swirling or because it's swirling so slow?

Yeah, they're far away. So it'll be twice as many stars in the sky.

Yeah. But the pattern changes.

The pattern will change a bit and there won't be the Milky Way because the Milky Way

across the sky is because we are looking in the disc of our galaxy. And you lose that.

Because the disc will be so disrupted. And it'll be also the spherical distribution.

And of course, many galaxies are like that. And that's probably because they have been through

mergers of this kind. If we survive four billion years, we would likely be able to survive beyond

that. What's the other thing on the horizon for humans in terms of the sun burning out,

all those kinds of interesting cosmological threats to our civilization?

Well, I think on the cosmological time scale, because it won't be humans because

even the evolution has got no faster than Darwinian. And I would argue it will be faster than

Darwinian in the future. Then we're thinking about six billion years before the sun dies.

So any entities watching the death of the sun, if they're still around, maybe it's different

much as we are from slime mold or something. And far more different still if they become

electronic. So on that time scale, we just can't predict anything. But I think going back to

the human time scale, then we've talked about whether there'll be people on Mars by the end of

a century. And even in these long perspectives, then indeed, this century is very special,

because it may see the transition between purely flesh and blood entities to those which are

sort of cyborgs. And that'll be an important transition in biology and complexity in this

century. But of course, the other importance, and this has been the theme of a couple of my older

books, is that this is the first century where one species, namely our species, has the future of

the planet in his hands. And that's because of two types of concerns. One is that there are more

of us where more demanding of energy and resources. And therefore we are for the first time,

changing the whole planet through climate change, loss of biodiversity and all those issues.

This has never happened in the past, because having enough humans have been much in power.

So this is an effect that's obviously is high on everyone's agenda now, and rightly so, because

we've got to ensure that we leave a heritage that isn't eroded or damaged to future generations.

And so that's one class of threats. But there's another thing that worries me, perhaps more than

many people seem to worry. And that's the threat of misuse of technology. And so this is particularly

because technologies empower even small groups of malevolent people or indeed, even careless people

to create some effect which could cascade globally. And to take an example, a dangerous

pathogen or pandemic. I mean, my worst nightmare is that there could be some small group that can

engineer a virus to make it more virulent or more transmissible than a natural virus. This is so

called gain of function experiments which were done on the flu virus 10 years ago and can be

done for others. And of course, we now know from COVID 19 that our world is so interconnected

that a disaster in one part of the world can't be confined to that part and we spread globally.

So it's possible for a few dissidents with expertise in biotech could create a global

catastrophe of that kind. And also, I think we need to worry about very large scale disruption by

cyber attacks. In fact, I quote in one of my books, a 2012 report from the American Pentagon

about the possibility of a state level cyber attack on the electricity grid in eastern United

States, which is it could happen. And it says at the end of this chapter that this would

merit a nuclear response. This is pretty scary possibility. That was 10 years ago. And I think

now what would have needed a state actor then could be done perhaps by a small group empowered

by AI. And so there's obviously been an arms race between the cyber criminals and the cyber

security people, not clear which side is winning. But the main point is that as we become more

dependent on more integrated systems, then we get more vulnerable. And as we have the knowledge,

then the misuse of that knowledge becomes more and more of a threat. And I say bio and cyber

are the two biggest concerns. And if we depend too much on AI and complex systems, then just

breakdowns, it may be that they break down. And even if it's an innocent breakdown, then it may be

pretty hard to mend it and just think how much worse the pandemic would have been if we'd lost

the internet in the middle of it. Because we depended more than ever for communication,

everything else on the internet and zooms and all that. And if that had broken down,

that would have made things far worse. And those are the kinds of threats that we I think need to

be more energized and politicians need to be more energized to minimize. And one of the things I've

been doing the last year, through being a member of our part of our parliament is sort of a, I

have to instigate a committee to think more on better preparedness for extreme technological

risks and things like that. So they're a big concern in my mind that we've got to make sure that we

can benefit from these advances but safely because the stakes are getting higher and the benefits

are getting great, as we know, huge benefits from computers, but also huge downsides as well.

And one of the things this war in Ukraine has shown, one of the most terrifying things outside

of the humanitarian crisis is that at least for me, I realized that the human capacity to initiate

nuclear war is greater than I thought. I thought the lessons of the past have been learned.

It seems that we hang on the brink of nuclear war with this conflict like every single day

where just one mistake or bad actor or the actual leaders of the particular nations launching a

nuclear strike and all hell breaks loose. So then adding to that picture cyber attacks and so on,

they can lead to confusion and chaos. And then out of that confusion,

calculations are made such that a nuclear weapon is launched and then you're talking about,

I mean, direct probably 60, 70% of humans on earth are dead instantly. And then the rest,

I mean, it's basically 99% of the human population is wiped out in the period of five years.

Well, it may not be that bad, but it will be a devastation for civilization, of course.

And of course, it will be quite right that this could happen very quickly because of

information coming in and there's hardly enough time for human collected and careful thought.

And there have been recorded cases of false alarms. There's everywhere,

where there have been suspected attacks from the other side and fortunately,

they've been realized to be false alarms, but this could happen. And there's a new

class of threats actually, which in our center in Cambridge, people are thinking about,

which is that the commander control system of the nuclear weapons and the submarine fleets and all

that is now more automated and could be subject to cyber attacks. And that's a new threat,

which didn't exist 30 years ago. And so I think, indeed, it's really a sort of scary world, I think.

And it's because things happen faster and human beings aren't in such direct and immediate control,

because so much is delegated to machines. And also because the world is so much more interconnected,

then some local event can cascade globally in a way it never could in the past and much faster.

Yeah, it's a double H sword because the interconnectedness brings a higher quality

of life across a lot of metrics. Yeah, it can do, but of course, there again,

I mean, if you think of supply chains where we get stuff from around the world,

then one lesson we've learned is that there's a trade off between resilience and efficiency and

it's resilient to have an inventory in stock and to depend on local supplies, whereas it's more

efficient to have long supply chains. But the risk there is that a break in one link in one chain

can screw up car production. And this has already happened in the pandemic. So there's a trade off.

And there are the examples. I mean, for instance, the other thing we learned was that

it may be efficient to have 95% of your hospital intensive care beds occupied all the time,

which has been the UK situation, where to do what the Germans do and always keep 20% of them free

for an emergency is really a sensible precaution. And so I think we've probably learned a lot of

lessons from COVID 19 and they would include rebalancing the trade off between resilience

and efficiency. Boy, the fact that COVID 19, a pandemic that could have been a lot, a lot worse,

brought the world to its knees anyway. It could be far worse in terms of its fatality rate or

something. Fatality rate, yeah. So the fact that that, I mean, it revealed so many flaws in our

human institutions. Yeah, yeah. Yes. And I think I'm rather pessimistic because I do worry about

the bad actor or the small group who can produce catastrophe. And if you imagine someone with

access to the kind of equipment that's available in university labs or industrial labs, and they

could create some dangerous pathogen, then even one such person is too many. And how can we stop

that? Because it's true that you can have regulations. I mean, academies are having meetings,

et cetera, about how to regulate these new biological experiments, et cetera, make them safe.

But even if you have all these regulations, then enforcing regulations is pretty hopeless. We can't

enforce the tax laws globally. We can't enforce the drug laws globally. And so similarly, we can't

readily enforce the laws against people doing these dangerous experiments, even if all the

governments say they should be prohibited. And so my line on this is that all nations are going to

face a big trade off between three things we value, freedom, security, and privacy.

And I think different nations will make that choice differently. The Chinese would give up

privacy and have more security, if not more liberty. But I think in our countries, I think we're

going to have to give up more privacy in the same way.

That's a really interesting trade off. But there's also something about human nature here, where

I personally believe that all humans are capable of good and evil. And there's some aspect to which

we can fight this by encouraging people, incentivizing people towards the better angels of their nature.

So in order for a small group of people to create, to engineer deadly pathogens, you have to have people

that for whatever trajectory took them in life wanting to do that kind of thing. And if we can

aggressively work on a world that sort of sees the beauty in everybody and encourages

the flourishing of everybody in terms of mental health, in terms of meaning, in terms of all those

kinds of things, that's one way to fight the development of weapons that can lead to atrocities.

Yes. And I completely agree with that and to reduce the reason why people feel embittered.

Yes. But of course, we've got a long way to go to do that, because if you look at the present world,

nearly everyone in Africa has reason to feel embittered, because their economic development

is lagging behind most of the rest of the world. And the prospects of getting out of the poverty trap

is rather bleak, especially if the population grows. Because for instance, they can't develop

like the Eastern Tigers by cheap manufacturing, because robots are taking that over, so that they

will naturally feel embittered by the inequality. And of course, what we need to have is some sort

of mega version of the Marshall Plan that helped Europe in the post World War II era

to enable Africa to develop. That will be not just an altruistic thing for Europe to do,

but in our interest. Because otherwise, those in Africa will feel massively disaffected.

And indeed, it's a manifestation of the excessive inequalities, the fact that the

2000 richest people in the world have enough money to double the income of the bottom billion.

And that's an indictment of the ethics of the world. And this is where my friend Stephen

Pinker and I have had some contact. We wrote joint articles on bio threats and all that.

But he writes these books being very optimistic about quoting figures about how

life expectancy has gone up, infant mortality has gone down,

literacy has gone up, and all those things. And he's quite right about that.

And so he says the world's getting better.

Do you disagree with your friends, Stephen Pinker?

Well, I mean, I agree with those facts. But I think he misses out parts of the picture,

because there's a new class of threats which hang over us now, which didn't hang over us in the past.

And I would also question whether we have collectively improved our ethics at all,

because let's think back to the Middle Ages. It's true that, as Pinker says,

the average person was in a more miserable state than they are today on average.

For all the reasons he quantifies, that's fine. But in the Middle Ages, there wasn't very much

that could have been done to improve people's lot in life because of lack of knowledge and lack

of science, etc. So the gap between the way the world was, which is pretty miserable,

and the way the world could have been, which wasn't all that much better, was fairly narrow.

Whereas now, the gap between the way the world is and the way the world could be

is far, far wider. And therefore, I think we are ethically more at fault in allowing this gap

to get wider than it was in medieval times. And so I would very much question and dispute

the idea that we are ethically in advance of our predecessors.

That's a lot of interesting hypotheses in there. It's a fascinating question of how much

is the size of that gap between the way the world is and the way the world could be

is a reflection of our ethics, or maybe sometimes it's just a reflection of a very large number of

people. Maybe it's a technical challenge too. It's not just one of our political systems.

Political systems. And we're trying to figure this thing out. There's a 20th century

tried this thing that sounded really good on paper of collective communism type of things,

and it turned out at least the way it was done there,

that leads to atrocities and the suffering and the murder of tens of millions of people.

Okay, so that didn't work. Let's try democracy. And that seems to have a lot of flaws,

but it seems to be the best thing we've got so far. So we're trying to figure this out

as our technologies become more and more powerful, have the capacity to do a lot of good to the world,

but also unfortunately have the capacity to destroy the entirety of the human civilization.

I think it's social media generally, which makes it harder to get a sort of moderate consensus,

because in the old days when people got their news filtered through responsible journalists

in this country, the BBC and the main newspapers, et cetera, they would muffle the crazy extremes.

Whereas now, of course, they're on the internet, and if you click on them, you get to the war

extreme. And so I think we are seeing a sort of dangerous polarization, which I think is going

to make all countries harder to govern. And that's something which I'm pessimistic about.

So to push back, it is true that brilliant people like you highlighting the limitations

of social media is making them realize the stakes and the failings of social media companies,

but at the same time, they're revealing the division. It's not like they're creating it,

they're revealing it in part. And so that puts a lot of, that puts the responsibility into the

hands of social media and the opportunity in the hands of social media to alleviate some of that

division. So it could in the long arc of human history result, so bringing some of those divisions

and the anger and the hatred to the surface, so that we can talk about it. And as opposed to

disproportionately promoting it, actually just surfacing it so we can get over it.

Well, you're assuming that the fat cats are more public spirited than the politicians.

And I'm not sure about that.

Yeah. I think there's a lot of money to be made in being publicly spirited. I think there's a

lot of money to be made in increasing the amount of love in the world, despite the sort of public

perception that all the social media companies heads are interested in doing is making money.

I think that may be true, but I just personally believe people being happy

is a hell of a good business model. And so making as many people happy, helping them flourish in a

long term way, that's a good way to make money. Well, I think guilt and shame are good motives

to make you behave better in future. That's my experience. From maybe in the political

perspective of certainness in this case. But it does make sense now that we can destroy ourselves

with nuclear weapons, with engineered pandemics and so on, that the aliens would show up.

That if I was the, had a leadership position, maybe as a scientist or otherwise in an alien

civilization, and I would come upon Earth, I would try to watch from a distance,

do not interfere. And I would start interfering when these life forms start becoming quite,

have the capacity to be destructive. And so, I mean, it is an interesting question when people

talk about UFO sightings and all those kinds of things that at least...

These are benign aliens you're thinking of.

Benign, yes. I mean, benign, almost curious, almost partially, as with all curiosity,

partially selfish to try to observe, is there something interesting about this particular

evolutionary system? Because I'm sure even to aliens, Earth is a curiosity.

Yeah. Well, it's in a very special stage, you know what I mean?

It's special. It's special. Perhaps a very short...

This century is very special among the 45 million centuries the Earth experienced already.

So, it is a very special time where they should be specially interested. But I think going back

to the politics, the other problem is getting people who have short term concerns to care about

the long term. By the long term, I now mean just looking 30 years or so ahead. I know people who've

been scientific advisors to governments and things, and they may make these points.

But of course, they don't have much traction because, as we know very well,

any politician has an urgent agenda of very worrying things to deal with. And so,

they aren't going to prioritize these issues which are longer term and less immediate and

don't just concern their constituents if they concern distant parts of the world.

And so, I think what we have to do is to enlist charismatic individuals

to convert the public. Because if the politicians know the public care about something,

climate change is an example, then they will make decisions which take cognizance of that.

And I think for that to happen, then we do need some public individuals who are respected by

everyone and to have a high profile. And in the climate context, I would say that I've mentioned

four very disparate people who've had such a big effect in the last few years. One is Pope Francis,

the other is David Attenborough, the other is Bill Gates, and the other is Greater Taunberg.

And those four people have certainly had a big shift in public opinion and

even changed the rhetoric of business, although how deep that is, I don't know.

But politicians can't let these issues drop down off the agenda if there's a public clamor.

And it needs people like that to keep the public clamor going.

To push back a little bit, so those four are very interesting and I have deep respect for them.

They have, except David Attenborough, David Attenborough is really, I mean, everybody loves him.

I mean, I can't say anything. But Bill Gates and Greta, they also create a lot of division.

Oh, sure. Yeah, yeah.

And this is a big problem. So it's not just charismatic. I put that responsibility actually

on the scientific community. And the populace too, yeah. And the politicians. So we need

the charismatic leaders. And they're rare. When you look at human history,

those are the ones that make a difference. Those are the ones that

not the ride, they inspire the populace to think long term. The JFK, we'll go to the

moon in this decade now because it's easy, but because it is hard. There's no discussion about

short term political gains or any of that kind of stuff in the vision of going to the moon,

or going to Mars, or taking on gigantic projects, or taking on world hunger, or taking on climate

change, or the education system, all those things that require long term, significant investment

that requires. But it's hard to find those people. And incidentally, I think another problem,

which is a downside of social media is that of younger people, I know the number who would

contemplate a political career has gone down because of the pressures on them and their family

from social media. It's a hell of a job now. And so I think we are all losers because the

quality of people who choose that path is really dropping. And as we see by the quality of those

who are in these compositions. That said, I think the silver lining there is the quality of the

competition actually is inspiring because it shows to you that there's a dire need of leaders,

which I think would be inspiring to young people to step into the fold. I mean, great leaders

are not afraid of a little bit of fire on social media. So if you have a 20 year old kid now,

a 25 year old kid is seeing how the world responded to the pandemic, seeing the geopolitical

division over the war in Ukraine, seeing the brewing war between the West and China,

we need great leaders. And there's a hunger for them. And the time will come when they step up.

I believe that. But also to add to your list of four, he doesn't get enough credit. I've been

defending him in this conversation. Elon Musk in terms of the fight and climate change.

But he also has led to a lot of division, but we need more. David Edinburgh.

Yeah, no, I mean, I'm definitely, I mean, I've heard him described as a 21st century Brunel

for his innovation. And that's true. But whether he's an ethical inspiration, I don't know.

Yeah, he has a lot of fun on Twitter. Well, let me ask you to put on your wise sage hat.

What advice would you give to young people today? Maybe they're teenagers in high school, maybe

early college. What advice would you give to a career or have a life they can be proud of?

Yes. Well, I'd be very different, really, about offering any wisdom. But I think they should

they should realize that the choices they make at that time are important. And from the experience

of I've had with many friends, many people don't realize that opportunities are open until it's too

late. They somehow think that some opportunities are only open to a few privileged people. And

they don't even try. And that they could succeed. But if I focus on people working in some professor

I know about like science, I would say, pick an area to work in, where new things are happening,

where you can do something that the old guys never had a chance to think about.

Don't go into a field that's fairly stagnant, because then there's not much to do, or you'll be

trying to tackle the problems that the old guys got stuck on. And so I think in science,

I can give people good advice that they should pick a subject where there are exciting new

developments. And also, of course, something which suits their style, because even when in

science, which is just one profession, there's a big range of style between the sort of

solitary thinker that a person does field work, the person who works in a big team, etc. And

whether you like computing or mathematical thought, etc. So pick some subject that suits your style

and where things are happening fast. And be prepared to be flexible. That's what I'd say,

really. Keep your eyes open for the opportunity throughout, like you said. Go to a new field,

go to a field where new cool stuff is happening. Just keep your eyes open. Yes, that's

patitudinous. But I think most of us, and I include myself in this, didn't realize these

sorts of things are too late. Yeah, I think this applies way beyond science. What do you make of

this finiteness of our life? Do you think about death? Do you think about mortality?

Do you think about your mortality? And are you afraid of death? Well, I mean, I'm not afraid,

because I think I'm lucky. I feel lucky to have laughed as long as I have. And to have been

fairly lucky in my life in many respects compared to most people. So I feel very fortunate.

This reminds me of this current emphasis on living much longer than these so called

Altos laboratories, which have been set up by billionaires. There's one in San Francisco,

one in La Jolla, I think, and one in Cambridge. And they're funded by these guys who,

when young, wanted to be rich. And now they're rich, they want to be young again. They won't

find that quite so easy. And do we want this? I don't know if there was some elite that was able

to do much longer than others. That would be a really fundamental kind of inequality. And I think

if it happened to everyone, then that might be an improvement. It's not so obvious. But I think

for my part, I think to have lived as long as most people and had a fortunate life is all I can

expect and a lot to be grateful for. Those are all past issues. Well, I am incredibly honored

that you sit down with me today. I thank you so much for life of exploring some of the deepest

mysteries of our universe and of our humanity and thinking about our future with existential

risks that are before us. It's a huge honor, Martin, that you sit with me. And I've really

enjoyed it. Well, thank you, Lex. I thought we couldn't go on for as long as this, but we could

have gone on much longer. Exactly. Thank you so much. Thank you for listening to this conversation

with Martin Rees. To support this podcast, please check out our sponsors in the description. And

now let me leave you with some words for Martin Rees himself. I'd like to widen people's awareness

of the tremendous time span lying ahead for our planet and for life itself. Most educated people

are aware that we're the outcome of nearly four billion years of Darwinian selection,

but many tend to think that humans are somehow the culmination. Our sun, however,

is less than halfway through its lifespan. It will not be humans who watch the sun's demise

six billion years from now. Any creatures that then exist will be as different from us as we are

from bacteria or amoeba. Thank you for listening and hope to see you next time.