Transcript
00:00:00 no reason to think that the ocean ends just beyond your horizon. And likewise, there’s no reason to
00:00:05 think that the aftermath of our Big Bang ends just at the boundary of what we can see. Indeed,
00:00:12 there are quite strong arguments that it probably goes on about 100 times further.
00:00:18 It may even go on so much further that all combinatorials are replicated. And there’s
00:00:24 another set of people like us sitting in a room like this. The following is a conversation with
00:00:32 Lord Martin Rees, Emeritus Professor of Cosmology and Astrophysics at Cambridge University and
00:00:38 co founder of the Center for the Study of Existential Risk. This is the Lex Friedman
00:00:43 podcast. To support it, please check out our sponsors in the description. And now,
00:00:48 dear friends, here’s Martin Rees. In your 2020 Scientific American article,
00:00:55 you write that, quote, today we know that the universe is far bigger and stranger than anyone
00:01:00 suspected. So what do you think are the strangest, maybe the most beautiful, or maybe even the most
00:01:07 terrifying things lurking out there in the cosmos? Well, of course, we’re still groping for any
00:01:13 detailed understanding of the remote parts of the universe. But of course, what we’ve learned in the
00:01:19 last few decades is really two things. First, we’ve understood that the universe had an origin
00:01:26 about 13.8 billion years ago, in a so called Big Bang, a hot 10 states, whose very beginnings are
00:01:33 still shrouded in mystery. And also, we’ve learned more about the extreme things in it, black holes,
00:01:39 neutron stars, explosions of various kinds. And one of the most potentially exciting discoveries
00:01:46 in the last 20 years, mainly in the last 10, has been the realization that most of the stars in the
00:01:53 sky are orbited by retinues of planets, just as the Sun is orbited by the Earth and the other
00:02:00 familiar planets. And this, of course, makes the night sky far more interesting. What you see up
00:02:05 there aren’t just points of light, but they’re planetary systems. And that raises the question,
00:02:10 could there be life out there? And so that is an exciting problem for the 21st century.
00:02:15 So when you see all those lights out there, you immediately imagine all the planetary worlds that
00:02:21 are around them, and they potentially have all kinds of different lives, living organisms,
00:02:29 life forms or different histories. Well, that we don’t know at all. We know
00:02:32 that these planets are there. We know that they have masses and orbits rather like the
00:02:39 planets of our solar system. But we don’t know at all if there’s any life on any of them. I mean,
00:02:44 it’s entirely logically possible that life is unique to this Earth, doesn’t exist anywhere.
00:02:50 On the other hand, it could be that the origin of life is something which happens routinely given
00:02:56 conditions like the young Earth, in which case there could be literally billions of places in
00:03:00 our galaxy where some sort of biosphere has evolved. And settling where the truth lies
00:03:07 between those two extremes is a challenge for the coming decades.
00:03:12 So certainly we’re either lucky to be here or very, very, very lucky to be here.
00:03:18 I guess that’s the difference. Where do you fall? Your own estimate,
00:03:25 your own guess on this question. Are we alone in the universe, do you think?
00:03:29 I think we’re foolish to give any firm estimate because we just don’t know. And that’s just an
00:03:35 example of how we are depending on greater observations. And also, incidentally,
00:03:40 in the case of life, we’ve got to take account of the fact that, as I always say to my scientific
00:03:47 colleagues, biology is a much harder subject than physics. And most of the universe that we know
00:03:54 about could be understood by physics. But we’ve got to remember that even the smallest living
00:03:59 organism, an insect, is far more complicated with layer on layer complexity than the most
00:04:08 complicated star or galaxy. That’s the funny thing about physics
00:04:13 and biology. The dream of physicists in the 20th century and maybe this century is to discover
00:04:19 the theory of everything. And there’s a sense that once you discover that theory,
00:04:27 you will understand everything. If we unlock the mysteries of how the universe works,
00:04:32 would you be able to understand how life emerges from that fabric of the universe that we understand?
00:04:39 I think the phrase, theory of everything, is very misleading because it’s used to describe
00:04:45 a theory which unifies the three laws of microphysics, electricity,
00:04:52 magnetism, and weak interaction with gravity. So it’s an important step forward for particle
00:04:57 physicists. But the lack of such a theory doesn’t hold up any other scientists. Anyone doing
00:05:04 biology or most of physics is not held up at all through not understanding subnuclear physics.
00:05:10 They’re held up because they’re dealing with things that are very complicated.
00:05:12 And that’s especially true of anything biological. So what’s holding up biologists is not a lack of
00:05:18 the so called theory of everything. It’s the inability to understand things which are very
00:05:23 complicated. What do you think we’ll understand first? How the universe works or how the human
00:05:30 body works deeply, like from a fundamental deep level? Well, I think, perhaps we can come back to
00:05:36 it later, that there are only limited prospects of ever being able to understand with unaided human
00:05:44 brains the most fundamental theories linking together all the forces of nature. I think that
00:05:51 may be a limitation of the human brains. But I also think that we can, perhaps aided by computer
00:05:58 simulations, understand a bit more of the complexity of nature. But even understanding a
00:06:06 simple organism from the atom up is very, very difficult. And I think extreme reductionists have
00:06:15 a very misleading perception. They tend to think that, in a sense, we are all solutions to
00:06:20 Schrodinger’s equation, etc. But that isn’t the way we’ll ever understand anything. It may be true
00:06:28 that we are reductionists in the sense that we believe that that’s the case. We don’t believe in
00:06:34 any special life force in living things. But nonetheless, no one thinks that we can understand
00:06:40 a living thing by solving Schrodinger’s equation. To take an example which isn’t as complicated,
00:06:46 lots of people study the flow of fluids like water, why waves break, why flows go turbulent,
00:06:52 things like that. This is a serious branch of applied mathematics and engineering. And in doing
00:06:59 this, you have concepts of viscosity, turbulence, and things like that. Now, you can understand
00:07:06 quite a lot about how water behaves and how waves break in terms of those concepts. But the fact
00:07:13 that any breaking wave is a solution of Schrodinger’s equation for 10 to the 30 particles,
00:07:20 even if you could solve that, which you clearly can’t, would not give you any insight.
00:07:26 So the important thing is that every science has its own irreducible concepts
00:07:32 in which you get the best explanation. So it may be in chemistry, it’s things like valence.
00:07:38 In biology, there are concepts in cell biology. And in ecology, there are concepts like
00:07:47 imprinting, etc. And in psychology, there are other concepts. So in a sense, the sciences are
00:07:55 like a tall building where you have basic physics, most fundamental, then the rest of
00:08:01 physics, then chemistry, then cell biology, etc., all the way up to the, I guess, economist in the
00:08:08 penthouse and all that. And we have that. And that’s true in a sense. But it’s not true that
00:08:15 it’s like a building in that it’s made unstable by an unstable base. Because if you’re a chemist,
00:08:23 biologist, or an economist, you’re facing challenging problems.
00:08:27 But they’re not made any worse by uncertainty about subnuclear physics.
00:08:33 TK And at every level, just because you understand the rules of the game,
00:08:37 or have some understanding of the rules of the game, doesn’t
00:08:40 TK mean you know what kind of beautiful things that game creates.
00:08:46 TK Right. So if you’re interested in birds and how they fly, then things like imprinting
00:08:56 the baby on the mother and all that, and things like that, are what you need to understand.
00:09:02 You couldn’t even in principle solve this fairly good equation, how an albatross
00:09:08 wanders for thousands of miles in the Southern Ocean and comes back and then coughs up
00:09:12 food for its young. That’s something we can understand, in a sense,
00:09:16 and predict the behavior. But it’s not because we can solve it on the atomic scale.
00:09:21 TK You mentioned that there might be some fundamental limitation to the human brain
00:09:26 that limits our ability to understand some aspect of how the universe works. That’s really
00:09:32 interesting. That’s sad, actually. To the degree it’s true, it’s sad. So what do you mean by that?
00:09:39 TK I would simply say that just as a monkey can’t understand quantum theory or even Newtonian
00:09:46 physics, there’s no particular reason why the human brain should have evolved to be well matched
00:09:52 to understanding the deepest aspects of reality. And I suspect that there may be aspects that we
00:09:59 are not even aware of and couldn’t really fully comprehend.
00:10:03 But as an intermediate step towards that, one thing which I think is a very interesting
00:10:07 possibility is the extent to which AI can help us. I mean, I think if you take the example of
00:10:14 so called theories of everything, one of which is string theory.
00:10:18 String theory involves very complicated geometry and structures in 10 dimensions.
00:10:24 And it’s certainly, in my view on the cards, that the physics of 10 dimensions,
00:10:36 very complicated geometry, may be too hard for a human being to work through,
00:10:42 but could be worked through by an AI with the advantage of the huge processing power,
00:10:50 which enables them to learn world championship chess within a few hours just by watching games.
00:10:55 So there’s every reason to expect that these machines could help us to solve these problems.
00:11:02 And of course, if that’s the way we came to understand whether string theory was right,
00:11:08 it should be in a sense frustrating because you wouldn’t get the sort of aha insight,
00:11:13 which is the greatest satisfaction from doing science. But on the other hand, if a machine
00:11:19 churns away at 10 dimensional geometry, figuring out all the possible origamis wound up in extra
00:11:26 dimensions, if it comes out at the end, spews out the correct mass of the electron, the fact that
00:11:32 there are three kinds of neutrinos, something like that, you would know that there was some truth in
00:11:36 the theory. And so we may have a theory which we come to trust because it does predict things that
00:11:43 we can observe and check, but we may never really understand the full workings of it to the extent
00:11:49 that we do more or less understand how most phenomena can be explained in a fundamental way.
00:11:57 Of course, in the case of quantum theory, many people would say,
00:12:01 understand if there’s still some mystery, if you don’t quite understand why it works.
00:12:04 But there could be deeper mysteries when we get to these unified theories, where there’s a big gap
00:12:09 between what a computer can print out for us at the end and what we can actually grasp and think
00:12:16 through in our heads. Yeah, it’s interesting that the idea that there could be things a computer
00:12:21 could tell us that is true. And maybe it can even help us understand why it’s true a little bit,
00:12:29 but ultimately it’s still a long journey to really deeply understand the whys of it.
00:12:34 Yes, and that’s the limitation of our brain. We can try to sneak up to it in different ways,
00:12:40 given the limitations of our brain. I’ve gotten a chance to spend the day at DeepMind,
00:12:45 talk to Demis Hassabis. His big dream is to apply AI to the questions of science,
00:12:52 certainly to the questions of physics. Have you gotten a chance to interact with him?
00:12:55 Well, I know him quite well. He’s one of my heroes, certainly.
00:12:59 I’m sure he would say the same.
00:13:02 And I remember the first time I met him, he said that he was like me, he wants to understand the
00:13:07 universe, but he thought the best thing to do was to try and develop AI. And then with the help of
00:13:12 AI, he’d stand more chance of understanding the universe. And I think he’s right about that.
00:13:18 And of course, although we’re familiar with the way his computers play go and chess,
00:13:26 he’s already made contributions to science through understanding protein folding better
00:13:33 than the best human chemists. And so already he’s on the path to showing ways in which computers
00:13:40 have the power to learn and do things by having ability to analyze enormous samples in a short
00:13:45 time to do better than humans. And so I think he would resonate for what I just said, that it may
00:13:52 be that in these other fundamental questions, the computers will play a crucial role.
00:13:58 Yeah. And they’re also doing a quantum mechanical simulation of electrons. They’re doing
00:14:03 control of high temperature plasmas, fusion reactors.
00:14:07 Yes, that’s a new thing, which is very interesting. They can suppress the instabilities
00:14:11 in these tokamaks better than any other way. Yeah.
00:14:14 And it’s just the march of progress by AIs in science is making big strides. Do you think
00:14:24 an AI system will win a Nobel Prize in the century? What do you think?
00:14:31 And does that make you sad?
00:14:33 If I can digress and put in a plug for my next book, it has a chapter saying,
00:14:38 why Nobel Prizes do more harm than good. So on a quite separate subject, I think
00:14:43 the Nobel Prizes do a great deal of damage to the perception of the way science is done.
00:14:49 Of course, if you ask who or what deserves the credit for any scientific discovery,
00:14:53 it may be often someone who has an idea, a team of people who work a big experiment, etc.
00:14:59 And of course, it’s the quality of the equipment, which is crucial. And certainly in the subjects
00:15:07 I do in astronomy, the huge advances we’ve had come not from us being more intelligent than
00:15:15 Aristotle was, but through us having far, far better data from powerful telescopes on the
00:15:22 ground and in space. And also, incidentally, we’ve benefited hugely in astronomy from computer
00:15:29 simulations. Because if you are a subatomic physicist, then of course, you crash together
00:15:36 the particles in the big accelerator like the one at CERN and see what happens. But I can’t
00:15:43 crash together two galaxies or two stars and see what happens. But in the virtual world of a
00:15:48 computer, one can do simulations like that. And the power of computers is such that these
00:15:56 simulations can yield phenomena and insights which we wouldn’t have guessed beforehand. And the way
00:16:05 we can feel we’re making progress and trying to understand some of these phenomena, why galaxies
00:16:11 have the size and shape they do and all that, is because we can do simulations and tweaking
00:16:16 different initial conditions and seeing which gives the best fit to what we actually observe.
00:16:22 And so that’s a way in which we’ve made progress in using computers. And incidentally, we also now
00:16:30 need to analyze data because one thinks of astronomy as being traditionally rather data
00:16:34 poor subjects. But the European satellite called Gaia has just put online the speeds and colors
00:16:43 and properties of nearly two billion stars in the Milky Way, which we can do fantastic analyses of.
00:16:50 And that, of course, could not be done at all without just the number crunching capacity
00:16:54 of computers. And the new methods of machine learning actually love raw data, the kind that
00:17:01 astronomy provides, organized, structured, raw data. Well, indeed, because the reason they really
00:17:06 have a benefit over us is that they can learn and think so much faster. That’s how they can
00:17:12 learn to play chess and go. That’s how they can learn to diagnose lung cancer better than a
00:17:17 radiologist because they can look at 100,000 scans in a few days, whereas no human radiologist sees
00:17:26 that many a lifetime. Well, there’s still magic to the human intelligence, to the intuition,
00:17:33 to the common sense reasoning. Well, we hope so. For now. What is the new book that you mentioned?
00:17:40 The book I mentioned is called If Science is to Save Us. It’s coming out in September.
00:17:44 And it’s on the big challenges of science, climate, dealing with biosafety and dealing
00:17:56 with cyber safety. And also, it’s got chapters on the way science is organized, universities
00:18:03 and academies, et cetera, and the ethics of science and education. And the limits, yes.
00:18:12 Yes. Well, let me actually just stroll around the beautiful and the strange of the universe.
00:18:18 Over 20 years ago, you hypothesized that we would solve the mystery of dark matter by now.
00:18:25 So unfortunately, we didn’t quite yet. First, what is dark matter and why has it been so tough
00:18:34 to figure out? Well, I mean, we learned that galaxies and other large scale structures,
00:18:39 which are moving around but preventive of flying apart by gravity, would be flying apart if they
00:18:50 only contain the stuff we see, if everything in them is shining. And to understand how galaxies
00:18:57 formed and why they do remain confined the same size, one has to infer that there’s about five
00:19:06 times as much stuff producing gravitational forces than the total amount of stuff in the
00:19:12 gas and stars that we see. And that stuff is called dark matter. That’s the leading name,
00:19:18 it’s not dark, it’s just transparent, et cetera. And the most likely interpretation is that it’s
00:19:26 a swarm of microscopic particles which have no electric charge. And the very small cross sections
00:19:34 were hitting each other and hitting anything else. So they swarm around and we can detect their
00:19:39 collective effects. And when we do computer simulations of how galaxies form and evolve
00:19:45 and how they emerge from the Big Bang, then we get a nice consistent picture if we put in
00:19:53 five times as much mass in the form of these mysterious dark particles. And for instance,
00:20:01 it works better if we think they’re not interacting particles than if you think they’re a gas which
00:20:05 would have shockwaves and things. So we know something about the properties of these, but we
00:20:09 don’t know what they are. And the disappointment compared to my guess 20 years ago is that
00:20:17 particles answering this description have not yet been found. It was thought that the
00:20:21 big accelerator, the Large Hadron Collider at CERN, which is the world’s biggest,
00:20:26 might have found a new class of particles which would have been the obvious candidates.
00:20:30 And it hasn’t. And some people say, well, dark matter can’t be there, etc. But what I would argue
00:20:38 is that there’s a huge amount of parameter space that hasn’t been explored. There are other kinds
00:20:44 of particles called axions which behave slightly differently, which are good candidates. And
00:20:50 there’s a factor of 10 powers of 10 between the heaviest particles that could be created by
00:20:58 the Large Hadron Collider and the heaviest particles which on theoretical grounds could exist
00:21:04 without turning into black holes. So there’s a huge amount of possible particles which could be
00:21:09 out there as remnants of the Big Bang, but which we wouldn’t be able to detect so easily. So the
00:21:16 fact that we’ve got new constraints on what the dark matter could be doesn’t diminish my belief
00:21:22 that it’s there in the form of particles because we’ve only explored a small fraction of parameter
00:21:27 space. So there’s this search, you’re literally, upon an unintended, are searching in the dark
00:21:36 here in this giant parameter space of possible particles. You’re searching for, I mean,
00:21:41 there could be all kinds of particles. There could be, and there’s some which may be very,
00:21:46 very hard to detect. But I think we can hope for some new theoretical ideas because one point which
00:21:53 perhaps we’d like to discuss more is about the very early stages of the Big Bang.
00:21:58 And the situation now is that we have an outline picture for how the universe has evolved from
00:22:06 the time when it was expanding in just a nanosecond up to the present. And we could do
00:22:12 that because after nanosecond, the physics of the material is in the same range that we can test in
00:22:20 the lab. After a nanosecond, the particles move around like those in the Large Hadron Collider.
00:22:27 If you wait for one second, they’re rather like in the centers of the hottest stars. And nuclear
00:22:34 reactions produce hydrogen, helium, et cetera, which fit the data. So we can with confidence
00:22:38 extrapolate back to when the universe was a nanosecond old. Indeed, I think we can do it with
00:22:43 as much confidence as anything a geologist tells you about the early history of the Earth.
00:22:47 And that’s huge progress in the last 50 years. But any progress puts in sharper focus new mysteries.
00:22:56 And of course, the new mysteries in this context are, why is the universe expanding the way it is?
00:23:02 Why does it contain this mixture of atoms and dark matter and radiation? And why does it have
00:23:10 the properties which allow galaxies to form, being fairly smooth but not completely smooth?
00:23:15 And the answer to those questions, I generally believe, to lie in a much, much earlier stage
00:23:21 of the universe, when conditions were much more extreme, and therefore far beyond the stage where
00:23:27 we have the foothold in experiments. Very theoretical. And so we don’t have a convincing
00:23:33 theory. We just have ideas. Until we have something like string theory or some other
00:23:38 clues to the ultra early universe, that’s going to remain speculative. So there’s a big gap.
00:23:44 And to say how big the gap is, if we take the observable universe out of a bit more than 10
00:23:50 billion light years, then when the universe was a nanosecond old, that would have been squeezed down
00:23:57 to the size of our solar system, or compressed into that volume. But the times we’re talking
00:24:05 about when the key properties of the universe were first imprinted were times when that entire
00:24:11 universe was squeezed down to the size of a tennis ball, or baseball if you prefer, and it emerged
00:24:18 from something microscopic. So it’s a huge extrapolation. And it’s not surprising that,
00:24:24 since it’s so far from our experimental range of detectability, we are still groping for ideas.
00:24:30 TG But you think first theory will reach into that place, and then experiment will perhaps
00:24:38 one day catch up, maybe simulation. JG Well, I think in a sense it’s a combination. I think
00:24:43 what we hope for is that there’ll be a theory which applies to the early universe,
00:24:51 which also has consequences which we can test in our present day universe, like discovering
00:25:00 why neutrinos exist or things like that. And that’s the thing which, as I mentioned,
00:25:05 we may perhaps need a bit of AI to help us to calculate. But I think the hope would be
00:25:11 that we will have a theory which applies under the very, very extreme early stages of the universe,
00:25:18 but which gains credibility and gains confidence, because it also manages to account for otherwise
00:25:23 unexplained features of the low energy world, what people call the standard model of particle
00:25:29 physics, where there are lots of undetermined numbers. So it may help with that. TG So we’re
00:25:35 dancing between physics and philosophy a little bit, but what do you think happened before the
00:25:42 Big Bang? So this feels like something that’s out of the reach of science. JG It’s out of the reach
00:25:49 of present science, because science develops and as the front is advanced, then new problems come
00:25:55 into focus that couldn’t even have been postulated before. I mean, if I think of my own career,
00:26:00 when I was a student, the evidence for the Big Bang was pretty weak, whereas now it’s extremely
00:26:07 strong. But we are now thinking about the reason why the universe is the way it is and all that.
00:26:14 So I would put all these things we’ve just mentioned in the category of speculative science.
00:26:21 And I don’t see a bifurcation between that and philosophy. But of course, to answer your question,
00:26:29 if we do want to understand the very early universe, then we’ve got to realize that
00:26:34 it may involve even more counterintuitive concepts than quantum theory does, because it’s a
00:26:40 condition even further away from everyday world than quantum theory is. And remember, our lives,
00:26:47 our brains evolved and haven’t changed much since our ancestors roamed the African savanna and
00:26:55 looked at the everyday world. And it’s rather amazing that we’ve been able to make some sense
00:27:00 of the quantum micro world and of the cosmos. But there may be some things which are beyond us. And
00:27:06 certainly, as you implied, there are things that we don’t yet understand at all. And of course,
00:27:11 one concept we might have to jettison is the idea of three dimensions of space and time just ticking
00:27:18 away. There are lots of ideas. I mean, I think Stephen Hawking had an idea. They’re talking about
00:27:26 what happened before the Big Bang. It’s like asking what happens if you go north from the
00:27:30 North Pole. It somehow closes off. That’s just one idea. I don’t like that idea, but that’s a
00:27:37 possible one. And so we just don’t know what happened at the very beginning of the Big Bang,
00:27:45 were there many Big Bangs rather than one, etc. And those are issues which we may be able to
00:27:53 get some foothold on from some new theory. But even then, we won’t be able to directly
00:28:04 test the theories. But I think it’s a heresy to think you have to be able to test every prediction
00:28:10 of a theory. Let me give you another example. We take seriously what Einstein’s theory says
00:28:16 about the inside of black holes, even though we can’t observe them, because that theory has been
00:28:23 vindicated in many other places in cosmology and black holes, gravitational waves, and all those
00:28:28 things. Likewise, if we had a theory which explains some things about the early history
00:28:36 of our Big Bang and the present universe, then we would take seriously the inference if it
00:28:43 predicted many Big Bangs, not one, even though we can’t predict the other ones. So the example is
00:28:49 we can take seriously a prediction if it’s the consequence of a theory that we believe
00:28:54 on other grounds. We don’t need to be able to detect another Big Bang in order to take it
00:29:00 seriously. It may not be a proof, but it’s a good indication that this is the direction where the
00:29:08 truth lies. Yeah, if the theory is getting confidence in other ways. Where do you sense?
00:29:14 Do you think there’s other universes besides our own? There are sort of well defined theories which
00:29:20 make assumptions about the physics at the relevant time, and this time, incidentally,
00:29:26 is 10 to the power minus 36 seconds or earlier than that, so this tiny sliver of time.
00:29:34 There are some theories, a famous one due to Andrei Linde, the Russian cosmologist now at
00:29:41 Stanford, called eternal inflation, which did predict an eternal production of new Big Bangs,
00:29:48 as it were, and that’s based on specific assumptions about the physics. But those
00:29:54 assumptions, of course, are just hypotheses which aren’t vindicated. But there are other
00:29:59 theories which only predict one Big Bang. So I think we should be open minded and not dogmatic
00:30:06 about these options until we do understand the relevant physics. But there are these different
00:30:12 scenarios of very different ideas about this. But I think all of them have the feature that
00:30:19 physical reality is a lot more extensive than what we can see through our telescope. I think
00:30:24 even most conservative astronomers would say that because we can see out with our telescopes to a
00:30:31 sort of horizon, which is about, depending on how you measure it, maybe 15 billion light years away
00:30:38 or something like that. But that horizon of observations is no more physical reality than
00:30:45 the horizon around you if you’re in the ocean and looking out at your horizon. There’s no reason to
00:30:53 think that the ocean ends just beyond your horizon. And likewise, there’s no reason to think that
00:30:59 the aftermath of our Big Bang ends just at the boundary of what we can see. Indeed,
00:31:05 there are quite strong arguments that it probably goes on about 100 times further.
00:31:10 It may even go on so much further that all combinatorials are replicated. And there’s
00:31:17 another set of people like us sitting in a room like this. That’s not logically impossible.
00:31:27 But I think many people would accept that it does go on and contain probably a million times
00:31:35 as much stuff as what we can see within a horizon. The reason for that, incidentally,
00:31:40 is that if we look as far as we can in one direction and in the opposite direction,
00:31:44 then the conditions don’t differ by more than one part in 100,000. So that means that if we’re part
00:31:50 of some finite structure, the gradient across the part we can see is very small. And so that
00:31:56 suggests that it probably does go on a lot further. And the best estimates say it must
00:32:01 go on at least 20 times further. LR – Is that exciting or terrifying to you?
00:32:07 Just the spans of it all, the wide, everything that lies beyond the horizon.
00:32:15 That example doesn’t even hold for Earth, so it goes way, way farther. And on top of that,
00:32:20 just to take your metaphor further on the ocean, while we’re on top of this ocean,
00:32:25 not only can we not see beyond the horizon, we also don’t know much about the depth of the ocean,
00:32:31 nor the actual mechanism of observation that’s in our head.
00:32:36 RL – I don’t think the perception of this utterly vast cosmos need have any deeper impact
00:32:59 on us than just realizing that we are very small on the scale of the external world.
00:33:04 LR – Yeah, it’s humbling though. It’s humbling, depending where your ego is, it’s humbling.
00:33:13 RL – Well, if you start off very unhumble indeed, it may make a difference. But for most of us,
00:33:17 I don’t think it makes much of a difference. Well, there’s a more general question, of course,
00:33:22 about whether the human race as such is something which is very special, or if on the other hand,
00:33:34 it’s just one of many such species elsewhere in the universe, or indeed existing at different
00:33:42 times in our universe. LR – To me, it feels almost obvious
00:33:48 that the universe should be full of alien life, perhaps dead alien civilizations, but
00:33:54 just the vastness of space. And it just feels wrong to think of Earth as somehow special. It
00:34:04 sure as heck doesn’t look that special. The more we learn, the less special it seems.
00:34:09 RL – Well, I mean, I don’t agree with that as far as life is concerned, because remember that
00:34:16 we don’t understand how life began here on Earth. We don’t understand, although we know there were
00:34:22 any evolution of simple life to complex life, we don’t understand what caused the transition
00:34:28 between complex chemistry and the first replicating, metabolizing entity we call alive.
00:34:35 That’s a mystery, and serious physicists and chemists are now thinking about it,
00:34:42 but we don’t know. So we therefore can’t say, was it a rare fluke which would not have happened
00:34:50 anywhere else, or was it something which involves a process that would have happened in any other
00:34:57 planet where conditions were like they were on the young Earth? So we can’t say that now. I think
00:35:04 many of us would indeed bet that probably some kind of life exists elsewhere. But even if you
00:35:11 accept that, then there are many contingencies going from simple life to present day life.
00:35:18 Some biologists like Stephen Jay Gould thought that if you reround evolution,
00:35:24 you’d end up with something quite different, and maybe not with an intelligent species. So
00:35:28 the contingencies in evolution may militate against the emergence of intelligence,
00:35:35 even if life gets started in lots of places. So I think these are still completely open questions,
00:35:40 and that’s why it’s such an exciting time now that we are starting to be able to address these.
00:35:45 I mentioned the fact that the origin of life is a question that we may be able to understand,
00:35:52 and serious people are working on it. It used to be put in a sort of too difficult box. Everyone
00:35:56 knew it was important, but they didn’t know how to tackle it or what experiments to do.
00:36:00 But it’s not like that now. That’s partly because of clever experiments, but I think most
00:36:06 importantly because we are aware that we can look for life in other places, other places in our
00:36:13 solar system, and of course, on the exoplanets around other stars. And within 10 or 20 years,
00:36:20 I think two things could happen, which would be really, really important. We might,
00:36:25 with the next big telescope, be able to image some of the Earth like planets around other stars.
00:36:32 TG. Image, like get a picture?
00:36:36 MR. Well, actually, caveat that, it’d take 50 years to get a resolved image,
00:36:41 but try to detect the light. Because now, of course, these exoplanets are detected by their
00:36:47 effects on the parent star. They either cause their parent star to dim slightly when they
00:36:52 transit across in front of it, and so we see the dips, or their gravitational pull makes the star
00:36:58 wobble a bit. So most of the 5,000 plus planets that have been found around other stars, they’ve
00:37:05 been found indirectly by their effect in one of those two ways on the parent star.
00:37:09 TG. You can still do a pretty good job estimating size, all those kinds of things.
00:37:13 MR. The size and the mass, you can estimate. But detecting the actual light from one of these
00:37:22 exoplanets hasn’t really been done yet, except for one or two very bright, big planets.
00:37:27 TG. So maybe like James Webb Telescope.
00:37:29 MR. Well, James Webb may do this, but even better will be the European ground based telescope
00:37:36 called Unimaginatively Extremely Large Telescope, which has a 39 meter diameter mirror. 39 meters,
00:37:42 a mosaic of eight hundred sheets of glass, and that will collect enough light from one of these
00:37:49 exoplanets around a nearby star to be able to separate out its light from that of the star,
00:37:57 which is millions of times brighter, and get the spectrum of the planet and see if it’s got
00:38:03 oxygen or chlorophyll and things in it. So that will come. James Webb may make some steps there.
00:38:11 But I think we can look forward to learning quite a bit in the next 20 years, because I like to say,
00:38:18 supposing that aliens were looking at the solar system. Then they’d see the sun as an ordinary
00:38:24 star. They’d see the Earth as, in Carl Sagan’s nice phrase, a pale blue dot lying very close in
00:38:31 the sky to its star, our sun, and much, much, much fainter. But if they could observe that dot,
00:38:38 they could learn quite a bit. They could perhaps get the spectrum of the light and find the
00:38:44 atmosphere. They’d find the shade of blue was slightly different, depending on whether the
00:38:49 Pacific Ocean or the land mass of Asia was facing them, so they could infer the length of the day
00:38:54 and the ocean and continents, and maybe something about the seasons and the climate.
00:39:00 That’s the kind of calculation and inference we might be able to draw within the next 10 or 20
00:39:08 years about other exoplanets. Evidence of some sort of biosphere on one of them would, of course,
00:39:16 be crucial, and it would rule out the still logical possibility that life is unique.
00:39:22 But there’s another way in which this may happen in the next 20 years. People think there could be
00:39:26 something swimming under the ice of Europa and Enceladus, and probes are being sent to maybe not
00:39:33 quite go under the ice but detect the spray coming out to see if there’s evidence for organics in
00:39:39 that. And if we found any evidence for an origin of life that had happened in either of those
00:39:47 places, that would immediately be important. Because if life has originated twice independently
00:39:54 in one planetary system, the solar system, that would tell us straight away it wasn’t a rare
00:39:59 accident and must have happened billions of times in the galaxy. At the moment, we can’t rule out
00:40:05 it being unique. And incidentally, if we found life on Mars, then that would still be ambiguous
00:40:11 because people have realized that this early life could have got from Mars to Earth or vice versa
00:40:18 on meteorites. So if you found life on Mars, then some skeptics could still say if it’s a single
00:40:24 origin. But I think that’s far enough away statistically. So that’s why that would be
00:40:31 especially… It’s always the skeptics that ruin a good party. But we need them, of course. We need
00:40:38 them at the party. We need some skeptics at the party. But boy, would that be so exciting to find
00:40:44 life on one of the moons. Because it means that life is everywhere. That’ll just be any kind of
00:40:52 vegetation or life. The question of the aliens of science fiction is a different matter.
00:40:58 LW. Intelligent aliens. Yeah, but if you have a good indication that there’s life elsewhere in
00:41:05 the solar system, that means life is everywhere. I don’t know if that’s terrifying or what that is.
00:41:15 Because if life is everywhere, why is intelligent life not everywhere? You’ve talked about that
00:41:22 most likely alien civilizations, if they are out there, they would likely be far ahead of us.
00:41:29 The ones that would actually communicate with us. And that, again, one of those things is both
00:41:38 exciting and terrifying. You’ve mentioned that they’re likely not to be of biological nature.
00:41:44 MR. Well, I think that’s important. Of course, again, it’s speculation. But in speculating about
00:41:51 intelligent life, and I take the search seriously. In fact, I chair the committee that the Russian
00:41:59 American investor Yuri Milner supports looking for intelligent life. He’s putting $10 million
00:42:05 a year into better equipment and getting time on telescopes to do this. And so I think it’s
00:42:11 worthwhile, even though I don’t hold my breath for success. It’s very exciting. But that does
00:42:18 lead me to wonder what might be detected. And I think, well, we don’t know. We’ve got to be
00:42:24 open minded about anything. We have no idea what it could be. And so any anomalous objects,
00:42:28 or even some strange shiny objects in the solar system, or anything we’ve got to keep our eyes
00:42:34 open for. But I think if we ask about a planet like the Earth, where evolution had taken more
00:42:44 of the same track, then, as you say, it wouldn’t be synchronized. If it had lagged behind, then,
00:42:51 of course, it would not have got to advanced life. But it may have had a head start. It may
00:42:57 have formed on a planet around an older star. But then let’s ask what we would see. It’s taken
00:43:04 nearly four billion years from the first life to us. And we now got this technological civilization
00:43:11 which could make itself detectable to any aliens out there. But I think most people would say
00:43:21 that this civilization of flesh and blood creatures in a collective civilization may not last more
00:43:29 than a few hundred years more. I think that some people would say it will kill itself off. But I’m
00:43:38 more optimistic. And I would say that what we’re going to have in future is no longer the slow
00:43:47 Darwinian selection. But we’re going to have what I call secular intelligent design, which will be
00:43:54 humans designing their progeny to be better adapted to where they are.
00:44:02 And if they go to Mars or somewhere, they’re badly adapted and they want to adapt a lot.
00:44:09 And so they will adapt. But there may be some limits to what could be done with flesh and blood.
00:44:15 And so they may become largely electronic, download their brains and be electronic entities.
00:44:23 And if they’re electronic, then what’s important is that they’re near immortal.
00:44:30 And also, they won’t necessarily want to be on a planet with an atmosphere or gravity. They may
00:44:36 go off into the blue yonder. And if they’re near immortal, they won’t be daunted by interstellar
00:44:41 travel taking a long time. And so if we looked at what would happen on the Earth in the next
00:44:51 millions of years, then there may be these electronic entities, which have been sent out
00:44:58 and are now far away from the Earth, but still sort of burping away in some fashion to be detected.
00:45:04 And so this therefore leads me to think that if there was another planet which had evolved like
00:45:13 the Earth and was ahead of us, it wouldn’t be synchronized, so we wouldn’t see a flesh and
00:45:19 blood civilization, but we would see these electronic progeny, as it were. And then this
00:45:26 raises another question, because there’s the famous argument against there being lots of
00:45:33 aliens out there, which is that they would come and invade us and eat us or something like that.
00:45:39 That’s a common idea, which Fermi is attributed to have been the first to say.
00:45:46 And I think there’s an escape clause to that, because these entities would be
00:45:54 evolved by second intelligent design, designed by their predecessors and then designed by us.
00:45:59 Whereas Darwinian selection requires two things. It requires aggression and intelligence. This
00:46:11 future intelligent design may favor intelligence, because that’s what they were designed for,
00:46:16 but it may not favor aggression. And so these future entities, they may be sitting deep thoughts,
00:46:23 they’re thinking deep thoughts, and not being at all expansionist. So they could be out there.
00:46:32 And we can’t refute their existence in the way the Fermi paradox is supposed to refute their
00:46:38 existence, because these would not be aggressive or expansionist.
00:46:41 Well, maybe evolution requires competition, not aggression. And I wonder if competition
00:46:46 can take forms that are non expansionary. So you can still have fun competing in the space
00:46:53 of ideas, which maybe primarily…
00:46:56 The Darwin philosophers, perhaps, yeah.
00:46:59 In a way, right. It’s an intellectual exercise versus a sort of violent exercise.
00:47:07 So what does this civilization on Mars look like? So do you think we would more and more
00:47:15 maybe start with some genetic modification and then move to basically cyborgs,
00:47:20 increasing integration of electronic systems, computational systems into our bodies and brains?
00:47:25 This is a theme of my other new book out this year, which is called The End of Astronauts.
00:47:31 The End of Astronauts.
00:47:33 It’s co written with my old friend and colleague from Berkeley, Don Goldsmith. And it’s really
00:47:40 about the role of human spaceflight versus sort of robotic spaceflight. And just to summarize
00:47:48 what it says, it argues that the practical case for sending humans into space is getting
00:47:56 weaker all the time as robots get better and more capable. Robots 50 years ago couldn’t
00:48:02 do anything very much, but now they could assemble big structures on space or in space
00:48:08 or on the moon, and they could probably do exploration. But present ones on Mars can’t
00:48:17 actually do the geology, but future AI will be able to do the geology and already they
00:48:24 can dig on Mars. And so if you want to do exploration of Mars, and of course, even more
00:48:31 of Enceladus or Europa where you could never send humans, we depend on robots. And they’re
00:48:37 far, far cheaper because to send a human to Mars requires feeding them for 200 days on
00:48:43 the journey there and bringing them back. And neither of those are necessary for robots.
00:48:48 So the practical case for humans is getting very, very weak. And if humans go, it’s only
00:48:54 as an adventure, really. And so the line in our book is that human spaceflight should
00:49:03 not be pursued by NASA or public funding agencies because it has no practical purpose, but also
00:49:12 because it’s especially expensive if they do it because they would have to be risk averse
00:49:19 in launching civilians into space. I can illustrate that by noting that the shuttle
00:49:27 was launched 135 times and it had two spectacular failures, which each killed the seven people in
00:49:35 the crew. And it had been mistakenly presented as safe for civilians. And there was a woman
00:49:42 schoolteacher killed in one of them. It was a big national trauma and they tried to make
00:49:46 it safer still. But if you launch into space, just the kind of people prepared to accept that
00:49:54 sort of risk, and of course, test pilots and people who go hang gliding and go to the South
00:50:00 Pole, et cetera, are prepared to accept a 2% risk at least for a big challenge, then of course,
00:50:06 you do it more cheaply. And that’s why I think human spaceflight should be left to the billionaires
00:50:16 and their sponsors because then the taxpayers aren’t paying and they can launch simply those
00:50:22 people who are prepared to accept high risks. Space adventure, not space tourism. And we should
00:50:31 cheer them on. And as regards where they would go, then low Earth orbit, as I suspect, can be done
00:50:40 quite cheaply in the future. But going to Mars, which is very, very expensive and dangerous for
00:50:46 humans. The only people who would go would be these adventurers, maybe on one way trip,
00:50:55 like some of the early polar explorers and Magellan and people like that. And we would
00:51:00 cheer them on. And I expect and I’ve ever hoped that by the end of a century, there will be a
00:51:07 small community of such people on Mars living very uncomfortably, far less comfortably than
00:51:16 at the South Pole or the bottom of the ocean or the top of Everest. But they will be there
00:51:21 and they won’t have a return ticket, but they’ll be there. Incidentally, I think it’s a dangerous
00:51:29 illusion to think, as Elon Musk has said, that we can have mass emigration from the Earth to Mars
00:51:38 to escape the Earth’s problems. It’s a dangerous illusion because it’s far easier to deal with
00:51:44 climate change on Earth than to terraform Mars to make it probably habitable to humans.
00:51:51 And so there’s no planet B for ordinary risk averse people. But for these crazy adventurers,
00:51:56 then you can imagine that they would be trying to live on Mars as great pioneers.
00:52:03 And by the end of a century, then there will be huge advances compared to the present in two
00:52:09 things. First, in understanding genetics, so as to genetically redesign one’s offspring. And
00:52:16 secondly, to use cyborg techniques to implant something in our brain or indeed think about
00:52:23 downloading, et cetera. And those techniques will, one hopes, be heavily regulated on Earth on
00:52:30 prudentials and ethical grounds. And of course, we are pretty well adapted to the Earth, so we
00:52:36 don’t have the incentive to do these things in the way they were there. So our argument is that
00:52:42 it’ll be those crazy pioneers on Mars using all these scientific advances, which will be
00:52:51 controlled here, away from the regulators, they will transition into a new post human species.
00:52:58 And so if they do that, and if they transition into something which is electronic,
00:53:04 eventually, because there may be some limits to the capacity of flesh and blood brains anyways,
00:53:10 then those electronic entities may not want to stay on a planet like Mars, they may want to go
00:53:16 away. And so they’ll be the precursors of the future evolution of life and intelligence coming
00:53:24 from the Earth. And of course, there’s one point which perhaps astronomers are more aware of than
00:53:29 most people. Most people are aware that we are the outcome of 4 billion years of evolution.
00:53:36 Most of them nonetheless, probably think that we humans are somehow the culmination,
00:53:42 the top of the tree. But yes, no astronomers can believe that because astronomers know
00:53:49 that the Earth is four and a half billion years old. The sun has been shiny for that length of
00:53:56 time. But the sun has got 6 billion years more to go before it flares up and engulfs the inner
00:54:01 planet. So the sun is less than halfway through its life. And the expanding universe goes on far
00:54:08 longer still, maybe forever. And I like to quote Woody Allen, who said, eternity is very long,
00:54:13 especially towards the end. So we shouldn’t think of ourselves as maybe even the halfway stage
00:54:19 in the emergence of cosmic complexity. And so these entities who are postcursors,
00:54:27 they will go beyond the solar system. And of course, even if there’s nothing else out there
00:54:32 already, then they could populate the rest of the galaxy. And maybe eventually meet the others who
00:54:40 are out there expanding as well. Expanding, populating with expanded capacity for life
00:54:48 and intelligence, all those kinds of things. Well, they might. But again, all better off.
00:54:55 We can’t conceive what they’d be like. They won’t be green men and women with eyes on stalks.
00:55:03 Maybe something quite different. We just don’t know. But there is an interesting question,
00:55:08 actually, which comes up when I’ve sometimes spoken to audiences about this topic,
00:55:12 but the question of consciousness and self awareness. Because going back to philosophical
00:55:17 questions, whether an electronic robot would be a zombie, or would it be conscious and self aware?
00:55:27 And I think there’s no way of answering this empirically. And some people think that
00:55:34 consciousness and self awareness is an emergent property in any sufficiently complicated networks
00:55:39 that they would be. Others say, well, maybe it’s something special to the flesh and blood that we’re
00:55:44 made of. We don’t know. And in a sense, this may not matter to the way things behave because
00:55:52 they could be zombies and still behave as though they were intelligent. But I remember
00:55:59 after one of my talks, someone came up and said, wouldn’t it be sad if these future entities,
00:56:06 which were the main intelligent in the universe, had no self awareness? So there was nothing
00:56:11 which could appreciate the wonder and mystery of the universe and the beauty of the universe
00:56:17 in the way that we do. And so it does perhaps affect one’s perspective of whether you welcome
00:56:24 or deplore this possible future scenario, depending on whether you think the future
00:56:30 post human entities are conscious and have an aesthetic sense or whether they’re just zombies.
00:56:36 And of course, you have to be humble to realize that self awareness may not be the
00:56:45 highest form of being, that humans have a very strong ego and a very strong sense of identity,
00:56:54 like personal identity connected to this particular brain. It’s not so obvious to me
00:57:00 that that is somehow the highest achievement of a life form, that maybe this kind of…
00:57:08 Do you think something collective would be?
00:57:10 It’s possible that, well, I think from an alien perspective, when you look at Earth,
00:57:17 it’s not so obvious to me that individual humans are the atoms of intelligence. It could be the
00:57:24 entire organism together, the collective intelligence. And so we humans think of
00:57:28 ourselves as individuals, we dress up, we wear ties and suits, and we’ll give each other prizes.
00:57:33 But in reality, the intelligence, the things we create that are beautiful emerges from our
00:57:39 interaction with each other. And that may be where the intelligence is, ideas jumping from
00:57:44 one person to another over generations.
00:57:47 Yes, but we have experiences where we can appreciate beauty and wonder and all that.
00:57:54 And a zombie may not have those experiences.
00:57:59 Yeah, or it may have a very different, a very black and white,
00:58:04 harsh description of a philosophical zombie that could be just a very different way to experience.
00:58:13 And, you know, in terms of the explorers that colonize Mars,
00:58:18 I mean, there’s several things I want to mention. One, it’s just at a high level. To me,
00:58:25 that’s one of the most inspiring things humans can do, is reach out into the unknown. That’s
00:58:31 in the space of ideas, in the space of science, but also the explorers.
00:58:34 Yes, no, I agree with that.
00:58:35 And that inspires people here on Earth more. I mean, it did in their, you know,
00:58:42 when going to the moon or going out to space in the 20th century, that inspired me.
00:58:46 I think that also could be used to inspire a generation of new scientists in the 21st century
00:58:54 by reaching out towards Mars. So in that sense, I think what Elon Musk and others are doing is
00:59:00 actually quite inspiring. It’s not, it’s not a recreational thing. It’s actually has a deep
00:59:07 humanitarian purpose of really inspiring the world. And then, you know, I think, you know,
00:59:12 I don’t think Elon says we want to escape Earth’s problems. It’s more that we should allocate some
00:59:22 small percentage of resources to have a backup plan. And because you yourself have spoken about
00:59:30 and written about all the ways we clever humans destroy ourselves.
00:59:35 You could go on.
00:59:36 And I’m not sure, it does seem when you look at the long arc of human history, it seems almost
00:59:45 obvious that we need to become a multi planetary species over a period. If we are to survive many
00:59:51 centuries, it seems that as we get clever and clever with the ways we can destroy ourselves,
00:59:59 Earth is going to become less and less safe. So in that sense, this is one of the things,
01:00:08 you know, people talk about climate change and that we need to respond to climate change. And
01:00:13 that’s a long term investment we need to make, but it’s not really long term. It’s a span of decades.
01:00:19 I think what Elon is doing is a really long term investment.
01:00:22 We should be working on multi planetary colonization now if we were to have it ready
01:00:29 five centuries from now. And so taking those early steps. And then also there’s something
01:00:35 happens when you go into the unknown and do this really difficult thing. You discover
01:00:42 something very new. You discover something about robotics. You discover something about
01:00:47 materials engineering or nutrition or neuroscience or human relations or political systems that
01:00:53 actually work well with humans. You discover all those things. And so it’s a worthy effort to go
01:00:59 out there and try to become cyborgs. Yeah, no, I agree with that. I think the only different point
01:01:08 I’d make is that this is going to be very, very, very, very, very, very, very, very, very, very, very,
01:01:17 very expensive if it’s done in a risk averse way. And that’s why I think we should be grateful to
01:01:24 the billionaires if they’re going to sort of foster these opportunities for thrill seeking
01:01:33 risk takers who we can all admire. Yeah. By the way, I should push back on the billionaires
01:01:38 because there’s sometimes a negative connotation to the word billionaire. It’s not a billionaire.
01:01:41 It’s a company versus government because governments are billionaires and trillionaires.
01:01:46 Yeah. It’s not the wealth. It’s the capitalist imperative, which I think
01:01:58 deserves a lot more praise than people are giving it. I’m troubled by the sort of criticism like
01:02:04 it’s billionaires playing with toys for their own pleasure. I think what some of these companies
01:02:11 like SpaceX and Blue Origin are doing is some of the most inspiring engineering and even scientific
01:02:19 work ever done in human history. No, I agree. I think the people who’ve made the greatest wealth
01:02:26 are people who’ve really been mega benefactors. I mean, I think, you know.
01:02:31 Some of them, some of them. Yeah, yes, some of them. But those who’ve founded Google and all
01:02:37 that and even Amazon, they’re beneficiaries. They’re in a quite different category, in my view,
01:02:44 from those who just shuffle around money or crypto coins and things like that.
01:02:52 Now you’re really talking trash.
01:02:54 Yes. But I think if they use their money in these ways, that’s fine. But I think it’s true that far
01:03:02 more money is owned by us collectively as taxpayers. But I think the fact is that in a democracy,
01:03:09 there’d be big resistance to exposing human beings to very high risks if in a sense we
01:03:16 share responsibility for it. And that’s the reason I think it would be done much more cheaply by
01:03:23 these private funders.
01:03:24 That’s an interesting hypothesis, but I have to push back. I don’t know if it’s obvious
01:03:29 why NASA spends so much money and takes such a long time to develop the things it was doing.
01:03:38 So before Elon Musk came along, because I would love to live in a world where government
01:03:44 actually uses taxpayer money to get some of the best engineers and scientists in the world
01:03:49 and actually work across governments, Russia, China, United States, European Union together
01:03:55 to do some of these big projects. It’s strange that Elon is able to do this much cheaper,
01:04:00 much faster. It could have to do with risk aversion, you’re right.
01:04:06 But I think it’s that he had all the whole assembly within this one building as it were,
01:04:15 rather than depending on a supply chain. But I think it’s also that he had a Silicon Valley
01:04:22 culture and had younger people, whereas the big aerospace companies, Boeing and Lockheed Martin,
01:04:28 they had people who were left over from the Apollo program in some cases. And so they weren’t
01:04:33 quite so lively. And indeed, quite apart from the controversial issues of the future of human
01:04:40 spaceflight, in terms of the next generation of big rockets, then the one that Musk is going to
01:04:48 launch for the first time this year, the huge one, is going to be far, far cheaper than the
01:04:55 one that NASA has been working on at the same time. And that’s because it will have a reusable
01:05:01 first stage. And it’s going to be great. It can launch over 100 tons into Earth orbit. And
01:05:09 incidentally, that’s going to make it feasible to do things that I used to think were crazy,
01:05:14 like having solar energy from space. That’s no longer so crazy if you can do that. And also,
01:05:21 for science, because its nose cone could contain within it something as big as the entire unfurled
01:05:31 James Webb telescope mirror. And therefore, you can have a big telescope much more cheaply if you
01:05:37 can launch it all in one piece. And so it’s going to be hugely beneficial to science and to any
01:05:43 practical use of space to have these cheaper rockets that are far more completely reusable
01:05:49 than anyways NASA had. So I think Musk’s done a tremendous service to space exploration and the
01:05:56 whole space technology through these rockets, certainly. Plus, it’s some big sexy rocket.
01:06:03 It’s just great engineering. Of course, yeah. It’s like looking at a beautiful big bridge
01:06:08 that humans are capable. Us descendants of apes are capable to do something so majestic.
01:06:12 Yes. And also the way they land coming down on this bar. That’s amazing.
01:06:16 It’s both controls engineering. It’s increasing sort of intelligence in these rockets, but also
01:06:24 great propulsion engineering materials, entrepreneurship. And it just inspires so
01:06:31 many people. No, I’m entirely with you on that. So would it be exciting to you to see a human
01:06:38 being step foot on Mars in your lifetime? Yes, I think it’s unlikely in my lifetime
01:06:43 since I’m so ancient. But I think this century, it’s going to happen. And I think that will
01:06:50 indeed be exciting. And I hope there will be a small community by the end of a century.
01:06:55 But as I say, I think they may go with one way tickets or accepting the risk of no return.
01:07:03 And so they’ve got to be people like that. And I still think it’s going to be hard to persuade
01:07:10 the public to send people when you say straight out that they may never come back. But of course,
01:07:18 the Apollo astronauts, they took a high risk. And in fact, in my previous book, I quote the
01:07:25 speech that has been written for Nixon to be read out if Neil Armstrong got stuck on the moon.
01:07:31 And it was written by one of his advisors and very eloquent speech about how they have come
01:07:42 to a noble end, et cetera. But of course, there was a genuine risk at that time. But that may have
01:07:51 been accepted. But clearly, the crashes of the shuttle were not acceptable to the American
01:07:59 public, even when they were told that this was only a 2% risk given how often they launched it.
01:08:05 And so that’s what leads me to think that it’s got to be left to the kind of people who are
01:08:13 prepared to take these risks. And I think of American Avengers, there was a guy called Steve
01:08:19 Fossett who was an aviator who did all kinds of crazy things. And then a guy who fell
01:08:25 supersonically with a parachute from very high altitude. All these people, we all share them on.
01:08:32 They extend the bounds of humanity. But I don’t think the public will be so happy to fund them.
01:08:39 I mean, I disagree with that. I think if we change the narrative, we should change the story.
01:08:44 You think so?
01:08:45 I think there’s a lot of people… Because the public is happy to fund folks in other domains
01:08:53 that take bold, giant risks. First of all, military, for example.
01:08:57 Oh, in the military, obviously, yes.
01:08:59 I think this is, in the name of science, especially if it’s sold correctly, I sure as hell would go
01:09:05 up there with a risk… I would take a 40% chance risk of death for something that’s…
01:09:12 I would. I might want to be even older than I am now. But then I would go.
01:09:17 I guess what I’m trying to communicate is there’s a lot of people on Earth. That’s the nice feature
01:09:22 and I’m sure there’s going to be a significant percentage or some percentage of people that are…
01:09:27 They take on the risk for the adventure. So, and I particularly love that that risk of adventure
01:09:36 when taking on inspires people and just the ripple effect it has across the generation,
01:09:40 especially among the young minds, is perhaps immeasurable. But you’re thinking that sending
01:09:50 humans should be something we do less and less, sending humans to space. That it should be
01:09:56 primarily an effort. The work of space exploration should be done primarily by robots.
01:10:03 Well, I think it can be done much more cheaply, obviously, on Mars. And no one’s thinking of
01:10:09 sending humans to Enceladus or Europa, the outer planets. And the point is we will have much better
01:10:18 robots. Because let’s take an example. You’ve seen the pictures of the moons of Saturn and the
01:10:27 picture of Pluto and the comet taken by probes and Cassini spent 13 years going around Saturn and
01:10:37 its moons after seven year voyage. And those are all based on 1990s technology. And if you think
01:10:43 of how smartphones have advanced in the 20 years since then, just think how much better one could
01:10:47 do instrumenting some very small, sophisticated probe. You could send dozens of them to explore
01:10:54 the outer planets. And that’s the way to do that. Because no one thinks you could send humans that
01:10:58 far. But I would apply the same argument to Mars. And if you want to assemble big structures like,
01:11:07 for instance, radio astronomers would like to have a big radio telescope on the far side of the moon
01:11:12 so it’s away from the Earth’s background artificial radio waves. And that could be
01:11:20 done by assembling using robots without people. So on the moon and on Mars, I think
01:11:29 everything that’s useful can be done by machines much more cheaper than by humans.
01:11:35 Do you know the movie 2001 A Space Odyssey?
01:11:39 Of course, yes. You must be too young to have seen that when it came out, obviously.
01:11:44 I remember seeing it when it came out.
01:11:46 You saw it when it came out.
01:11:48 Yeah, yeah, 50 years ago.
01:11:50 60, when was it? 60, in the 60s.
01:11:54 Yeah, that’s right. Still a classic.
01:11:58 It’s still probably, for me, the greatest AI movie ever made.
01:12:03 Yes, yes, I agree.
01:12:04 One of the great space movies ever made.
01:12:06 Yes. Well, let me ask you a philosophical question. Since we’re talking about robots
01:12:12 exploring space, do you think HAL 9000 is good or bad? So for people who haven’t watched,
01:12:20 this computer system makes a decision to basically prioritize the mission that
01:12:28 the ship is on over the humans that are part of the mission. Do you think HAL is good or evil?
01:12:38 If you ask me, probably in that context, it was probably good. But I think you’re raising
01:12:43 what is, of course, very much an active issue in everyday life about the extent to which we should
01:12:50 entrust any important decision to a machine. And there again, I’m very worried, because I think
01:12:58 if you are recommended for an operation or not given parole from prison or even denied credit
01:13:06 by your bank, you feel you should be entitled to an explanation. It’s not enough to be told that
01:13:13 the machine has a more reliable record on the whole than humans have of making these decisions.
01:13:20 You think you should be given reasons you could understand. And that’s why I think the present
01:13:26 societal trend to take away the humans and leave us in the hands of decisions that we can’t contest
01:13:37 is a very dangerous one. I think we’ve got to be very careful of the extent to which AI,
01:13:44 which can handle lots of information, actually makes the decision without oversight. And I think
01:13:50 we can use them as a supplement. But to take the case of radiology and cancer,
01:13:57 I mean, it’s true that the radiologist hasn’t seen as many x rays of cancer lungs as the machine. So
01:14:08 the machine could certainly help, but you want the human to make the final decision. And I think
01:14:12 that’s true in most of these instances. But if we turn a bit to the short term concerns with
01:14:19 robotics, I think the big worry, of course, is the effect it has on people’s self respect and
01:14:27 their labor market. And I think my solution would be that we should arrange to tax more heavily
01:14:36 the big international conglomerates, which use the robots and use that tax to fund
01:14:48 decently paid, dignified posts of the kind where being a human being is important.
01:14:54 Above all, carers for old people, teachers assistants for young, gardens in public parks,
01:14:59 and things like that. And if the people who are now working in mind numbing jobs in Amazon
01:15:05 warehouses, or in telephone call centers, are automated, but those same people are given
01:15:15 jobs where being a human is an asset, then that’s a plus plus situation. And so that’s
01:15:22 the way I think that we should benefit from these technologies, take over the mind numbing jobs,
01:15:31 and use machines to make them more efficient, but enable the people so displaced to do jobs
01:15:40 where we do want a human being. I mean, most people when they’re old, they’re rich people
01:15:46 if they have the choice. They want human carers and all that, don’t they? They may want robots
01:15:51 to help with some things, empty the bed pans and things like that, but they want real people. And
01:15:59 certainly in this country, I think even worse in America, the care of old people is completely
01:16:06 inadequate. And it needs just more human beings to help them cope with everyday life and look after
01:16:11 them when they’re sick. And so that seems to be the way in which the money raised in tax from
01:16:19 these big companies should be deployed. So that’s in the short term, but if you actually just look,
01:16:24 the fact is where we are today to longterm future in a hundred years, it does seem that
01:16:31 there is some significant chance that the human species is coming to an end in its
01:16:39 pure biological form. There’s going to be greater and greater integration
01:16:43 through genetic modification and cyborg type of creatures. And so you have to think, all right,
01:16:50 well, we’re going to have to get from here to there and that process is going to be painful.
01:16:56 And there’s so many different trajectories that take us from one place to another.
01:17:02 It does seem that we need to deeply respect humanness and humanity, basic human rights,
01:17:09 human welfare, like happiness and all that kind of stuff.
01:17:14 No, absolutely. And that’s why I think we ought to try and slow down the application of these
01:17:20 human enhancement techniques and cyborg techniques for humans for just that reason. I mean,
01:17:26 that’s why I want to lead into the people on Mars, let them do it, but for just that reason.
01:17:32 But there are people too. Okay. People on Mars are people too. I tend to, you know.
01:17:37 But they are very poorly adapted to where they are. That’s why they need this modification,
01:17:42 whereas we’re adapted to the Earth quite well. So we don’t need these modifications. We’re
01:17:49 happy to be humans living in the environment where our ancestors lived. So we don’t have the same
01:17:55 motive. So I think there’s a difference. But I agree, we don’t want drastic changes probably in
01:18:01 our lifestyle. And that indeed is a worry because some things are changing so fast.
01:18:06 But I think I’d like to inject a note of caution. If you think of the way progress in one technology
01:18:13 goes, it goes in a sort of spurt. It goes up very fast and then it levels off. Let me give you
01:18:22 two examples. One we’ve had already, a human space flight. At the time of the Apollo program,
01:18:28 which was only 12 years after Sputnik 1, I was alive then. And I thought it would only be 10
01:18:35 or 20 years further before there were footprints on Mars. But as we know, for reasons we could all
01:18:41 understand, that still remains the high point of human space exploration. That’s because it was
01:18:50 funded for reasons of superpower rivalry at huge public expense. But let me give you another case,
01:18:57 civil aviation. If you think of the change between 1919, when that was Alcock and Brown’s first
01:19:05 transatlantic fight, to 1979, the first flight of the jumbo jet. It was a big change. But it’s more
01:19:12 than 50 years since 1969. And we still have jumbo jets more or less the same. So that’s an example
01:19:17 of something which developed fast. And to take another analogy, we’ve had huge developments in
01:19:24 mobile phones. But I suspect the iPhone 24 may not be too different from the iPhone 13.
01:19:32 They develop, but then they saturate, and then maybe some new innovation takes over
01:19:39 in stimulating economic growth. Yeah, so it’s that we have to be cautious about being too optimistic,
01:19:47 and we have to be cautious about being too cynical. I think that is the
01:19:52 optimistic is begging the question. I mean, do we want this rapid change?
01:19:56 Right. So first of all, there’s some degree to which technological advancement is something,
01:20:01 is a force that can’t be stopped. And so the question is about directing it versus stopping it
01:20:07 or slowing it. Well, it can be sort of sloped or slow. We’ll take human spaceflight. There could
01:20:11 have been footprints on Mars if America had gone on spending 4% of the federal budget on the project
01:20:19 after Apollo. There were very good reasons, and we could have had supersonic flight, but Concorde
01:20:29 came and went during the 50 years. But the reason it didn’t progress is not because we realize it’s
01:20:37 not good for human society. The reason it didn’t progress is because it couldn’t make,
01:20:41 sort of from a capitalist perspective, it couldn’t make, there was no short term or long term way for
01:20:47 it to make money. So for me, it isn’t, but that’s the same as saying it’s not good for society.
01:20:54 I don’t think everything that makes money is good for society and everything that doesn’t make money
01:20:59 is bad for society, right? That’s a difficult thing we’re always contending with.
01:21:06 That’s a difficult thing we’re always contending with when we look at social networks. It’s not
01:21:14 obvious, even though they make a tremendous amount of money, that they’re good for society,
01:21:19 especially how they’re currently implemented with advertisement and engagement maximization.
01:21:24 So that’s the constant struggle.
01:21:26 But I would have thought that supersonic flight was something that would benefit only a tiny
01:21:38 elite at a huge expense and environmental damage. That was obviously something which we’re very
01:21:44 glad not to have, in my opinion.
01:21:46 Yeah, but perhaps there was a way to do it where it could benefit the general populace.
01:21:51 If you were to think about airplanes, wouldn’t you think that in the early days, airplanes would
01:21:56 have been seen as something that can surely only benefit 1% at most of the population,
01:22:03 as opposed to a much larger percentage? There’s another aspect of capitalist system that’s able
01:22:09 to drive down costs once you get the thing kind of going. So we get together maybe with taxpayer
01:22:15 money and get the thing going at first. And once it gets going, companies step up and drive down
01:22:21 the cost and actually make it so that blue collar folks can actually start using the stuff.
01:22:26 Yeah, sometimes that does happen. That’s good.
01:22:29 Yeah. So that’s, again, the double edged sword of human civilization, that some technology
01:22:37 hurts us, some benefits us, and we don’t know ahead of time. We can just do our best.
01:22:41 Yes. There’s a gap between what could be done and what we collectively decide to do.
01:22:49 Yes.
01:22:49 And it could push forward some developments faster than we do.
01:22:55 Let me ask you, in your book on the future prospects for humanity,
01:23:01 you imagine a time machine that allows you to send a tweet length message to scientists in
01:23:05 the past, like to Newton. What tweet would you send? It’s an interesting thought experiment.
01:23:12 What message would you send to Newton about what we know today?
01:23:15 Well, I think he’d love to know that there were planets around other stars. He’d like to know
01:23:22 that everything was made of atoms. He’d like to know that if he looked a bit more carefully
01:23:29 through his prisms and looked at light, not just from the sun, but from some flames,
01:23:38 he might get the idea that different substances emitted light of different colors, and he might
01:23:44 have been twigged to discover some things that had to wait 200 or 300 years. Could have given him
01:23:51 those clues, I think. It’s fascinating to think, to look back at how little
01:23:59 he understood, people at that time understood about our world.
01:24:04 Yes. And certainly about the cosmos.
01:24:07 About the cosmos, yes.
01:24:08 Well, if you think about astronomy, then until about 1850, astronomy was a matter of
01:24:19 the positions of how the stars and the planets moved around. Of course, that goes back a long
01:24:25 way, but Newton understood why the planets moved around in ellipses. But he didn’t understand
01:24:31 why the solar system was all in a plane, what we call the ecliptic, and he didn’t understand it.
01:24:39 No one did until the mid 19th century what the stars are made of. I mean, they were thought to
01:24:44 be made of some fifth essence, not earth, air, fire, and water like everything else,
01:24:49 and it was only after 1850 when people did use prisms more precisely to get spectra that they
01:24:56 realized that the sun was made of the same stuff as the earth, and indeed the stars were. It wasn’t
01:25:04 until 1930 that people knew about nuclear energy and knew what kept the sun shining for so long.
01:25:12 So it was quite late that some of these key ideas came in, which would have completely
01:25:17 transformed Newton’s views, and of course, the entire scale of the galaxy and the rest of the
01:25:25 universe. Just imagine what he would have thought about the Big Bang, or even just general
01:25:30 relativity, just gravity, just him and Einstein talking for a couple weeks. Would he be able to
01:25:39 make sense of space time and the curvature of space time? Well, I think given a quick course,
01:25:46 I mean, he was sort of, if one looks back, he was really a unique intellect in a way,
01:25:51 you know, and he said that he thought better than everyone else by thinking on things continually,
01:26:00 and thinking very deep thoughts, and so he was an utterly remarkable intellect, obviously.
01:26:06 But of course, scientists aren’t all like that. I think one thing that’s interesting to me,
01:26:10 having spent a life among scientists, is what a variety of mindsets and mental styles they have.
01:26:16 And just to contrast Newton and Darwin, Darwin said, and he’s probably correct, that he thought
01:26:30 he just had as much common sense and reasoning power as the average lawyer. And that’s probably
01:26:38 true because his ability was to sort of collect data and think through things deeply. That’s a
01:26:45 quite different kind of thinking from what was involved in Newton or someone doing abstract
01:26:50 mathematics. I think in the 20th century, the coolest, well, there’s the theory, but
01:26:59 from an astronomy perspective, black holes is one of the most fascinating entities to have been,
01:27:08 through theory and through experiment, to have emerged from. Obviously, I agree. It’s an amazing
01:27:13 story. Well, of course, what’s interesting is Einstein’s reaction because, as you know,
01:27:22 we now accept this is one of the most remarkable predictions of Einstein’s theory. He never took
01:27:27 it seriously, even believed it, although it was a consequence of a solution of his equations,
01:27:34 which someone discovered just a year after his theory, Schwarzschild. But he never took it
01:27:40 seriously, and others did. But then, of course, well, this is something that I’ve been involved
01:27:47 in actually finding evidence for black holes, and that’s come in the last 50 years. So now,
01:27:53 there’s pretty compelling evidence that they exist as the remnants of stars or big ones in
01:27:58 the center of galaxies. And we understand what’s going on. We have ideas, vaguely on how they form.
01:28:07 And, of course, gravitational waves have been detected, and that’s an amazing piece of technology.
01:28:14 Ligo is one of the most incredible engineering efforts of all time.
01:28:18 That’s an example where the engineers deserve most of the credit because the precision is,
01:28:23 as I said, it’s like measuring the thickness of a hair at the distance of Alpha Centauri.
01:28:28 Yeah, it’s incredible.
01:28:30 Tens to minus 21.
01:28:31 So maybe, actually, if we step back, what are black holes? What do we humans understand about
01:28:36 black holes and what’s still unknown?
01:28:40 Einstein’s theory, extended by people like Roger Penrose, tells us that black holes are,
01:28:47 in a sense, rather simple things, basically, because they are solutions of Einstein’s equations.
01:28:54 And the thing that was shown in the 1960s by Roger Penrose in particular, and by a few other
01:29:01 people, was that a black hole, when it forms and settles down, is defined just by two quantities,
01:29:09 its mass and its spin. So they’re actually very standardized objects. It’s amazing that objects
01:29:14 as standardized as that can be so big and can lurk in the rest of the solar system.
01:29:20 And so that’s the situation for a ready formed black hole. But the way they form, obviously,
01:29:27 is very messy and complicated. And one of the things that I’ve worked on a lot is what the
01:29:36 phenomena are, which are best attributed to black holes, and what may lead to them, and all that.
01:29:43 Which, can you explain to that? So what are the different phenomena
01:29:46 that lead to a black hole? Let’s talk about it. This is so cool.
01:29:49 Oh, okay. Well, I think one thing that only became understood, really,
01:29:56 in the 1950s, I suppose, and beyond was how stars evolve differently depending on how
01:30:05 heavy they are. The sun burns hydrogen to helium, and then when it’s run out of that,
01:30:11 it contracts to be a white dwarf. And we know how long that will take. It’ll take about 10 billion
01:30:16 years altogether for its lifetime. But big stars burn up their fuel more quickly, and more
01:30:23 interestingly, because when they’ve turned hydrogen to helium, they then get even hotter,
01:30:27 so they can fuse helium into carbon and go up the periodic table. And then they eventually
01:30:33 explode when they have an energy crisis, and they blow out that process material,
01:30:38 which, as a digression, is crucially important because all the atoms inside our bodies
01:30:44 were synthesized inside a star, a star that lived and died more than five billion years ago
01:30:50 before our solar system formed. And so we each have inside us atoms made in thousands of different
01:30:55 stars all over the Milky Way, and that’s an amazing idea. My predecessor, Fred Hoyle,
01:31:00 in 1946 was the first person to suggest that idea, and that’s been borne out. That’s a wonderful
01:31:05 idea. So that’s how massive stars explode. And they leave behind something which is very exotic
01:31:15 of two kinds. One possibility is a neutron star, and these were first discovered in 1967,
01:31:21 68. These are stars a bit heavier than the sun, which are compressed to an amazing density,
01:31:29 so the whole mass of more than the sun’s mass is in something about 10 miles across.
01:31:34 So they’re extraordinarily dense, they’re exotic physics, and they’ve been studied in immense
01:31:46 detail. And they’ve been real laboratories because the good thing about astronomy, apart from
01:31:51 exploring what’s out there, is to use the fact that the cosmos has provided us with a lab
01:31:57 with far more extreme conditions than we could ever simulate. And so we learn lots of basic
01:32:01 physics from looking at these objects, and that’s been true of neutron stars. But for black holes,
01:32:06 that’s even more true because the bigger stars, when they collapse, they leave something behind
01:32:14 in the center which is too big to be a stable white 2 or 4 neutron star and becomes a black hole.
01:32:19 And we know that there are lots of black holes weighing about 10 or up to 50 times as much as the
01:32:25 sun, which are the remnants of stars. They were detected first 50 years ago, when a black hole
01:32:33 was orbiting around another star and grabbing material from the other star which swirled into
01:32:40 it and gave us X rays. So the X rays astronomers found these objects orbiting around an ordinary
01:32:48 star and emitting X ray radiation very intensely, varying on a very short time scale. So something
01:32:56 very small and dense was giving that radiation. That was the first evidence for black holes.
01:33:00 But then the other thing that happened was realizing that there was a different class
01:33:05 of monster black holes in the centers of galaxies. And these are responsible for what’s called
01:33:12 quasars, which is when something in the center of a galaxy is grabbing some fuel and outshines all
01:33:19 the hundred billion stars or so in the rest of the galaxy. A giant beam of light. And in many
01:33:26 cases, it’s a beam of… That’s got to be the most epic thing the universe produces is quasars.
01:33:35 Well, it’s a debate about what’s the most epic, but quasars maybe or maybe gamma ray bursts or
01:33:40 something, but they are remarkable and they were a mystery for a long time. And they’re
01:33:45 one of the things I worked on in my younger days. So even though they’re so bright,
01:33:50 they’re still a mystery and you can only see them. I think they’re less of a mystery now.
01:33:54 I think we do understand basically what’s going on. How were quasars discovered?
01:34:00 Well, they were discovered when astronomers found things that looked like stars and that they were
01:34:05 small enough to be a point like and not resolved by a telescope, but outshone an entire galaxy.
01:34:13 Yeah. That’s suspicious.
01:34:15 Yes. But then they realized that what they were, they were objects which you now know are black
01:34:25 holes and black holes were capturing gas and that gas was getting very hot, but it was producing
01:34:33 far more energy than all the stars added together. And it was the energy of the black hole that was
01:34:43 lighting up all the gas in the galaxy. So you’ve got a spectrum of it there. So this was something
01:34:50 which was realized from the 1970s onwards. And as you say, the other thing we’ve learned is that
01:34:56 they often do produce these jets squirting out, which could be detected in all wave bands. So
01:35:03 there’s now a standard picture.
01:35:05 So there’s a giant black hole generating jets of light at the center of most galaxies.
01:35:10 Yes. That’s right.
01:35:11 Do we know, do we have a sense if every galaxy has one of these big boys, big black holes?
01:35:18 Most galaxies have big black holes. They vary in size. The one in our galactic center.
01:35:23 Do we know much about ours?
01:35:25 We do. Yes. We know it weighs about as much as 4 million suns, which is less than some,
01:35:34 it’s several billion other galaxies. But we know this one in our galactic center
01:35:40 isn’t very bright or conspicuous. And that’s because not much is falling into it at the
01:35:46 moment. If a black hole is isolated, then of course it doesn’t radiate. All that radiates
01:35:52 is gas swirling into it, which is very hot or has magnetic fields.
01:35:57 It’s only radiating the thing it’s murdering or consuming, however you put it.
01:36:01 Yeah, that’s right. And so it’s thought that our galaxy may have been bright at some time
01:36:07 in the past, but now that’s when the black hole formed or grew. But now it’s not capturing
01:36:16 very much gas. And so it’s rather faint and detected indirectly and by fairly weak radio
01:36:24 emission. And so I think the answer to your question is that we suspect that most galaxies
01:36:31 have a black hole in them. So that means at some stage in their lives, or maybe one or
01:36:36 more stages, they went through a phase of being like a quasar where that black hole
01:36:41 captured gas and became very, very bright. But for the rest of their lives, the black
01:36:47 holes are fairly quiescent because there’s not much gas falling into them.
01:36:53 And so this universe of ours is sprinkled with a bunch of galaxies and giant black holes with
01:37:01 very large number of stars orbiting these black holes and then planets orbiting.
01:37:08 Likely, it seems like planets orbiting almost every one of those stars and just this beautiful
01:37:17 universe of ours. Well, what happens when galaxies collide, when these two big black holes
01:37:24 collide? Well, what would happen is that… Well, and I should say that this is going to happen
01:37:32 near us one day, but not for 4 billion years because the Andromeda galaxy, which is the
01:37:37 biggest galaxy near to us, which is about nearly 3 million light years away, which is a big disk
01:37:44 galaxy with a black hole in its hub, rather like our Milky Way. And that’s falling towards us
01:37:53 because they’re both in a common gravitational potential well. And that will collide with our
01:37:59 galaxy in about 4 billion years. But maybe it’ll be less a collision and more of a dance because
01:38:05 it’ll be like a swirling situation. But eventually, there’ll be a merger. They’ll
01:38:10 go through each other and then merge. In fact, there are nice movies to be made of this,
01:38:16 computer simulations, and it’ll go through. And then there’s a black hole in the center of
01:38:26 Andromeda and our galaxy. And the black holes will settle towards the center. Then they will
01:38:34 orbit around each other very fast, and then they will eventually merge. And that’ll produce a big
01:38:39 burst of gravitational waves, a very big burst. That an alien civilization with a LIGO like
01:38:45 detector will be able to detect. Yes. Well, in fact, we can detect these
01:38:50 with their lower frequencies than the ways that will be detected by LIGO. So there’s a
01:38:57 spatial interferometer which can detect these. It’s about one cycle per hour rather than about
01:39:04 100 cycles per second. It’s the ones that detect it. But that will happen. But thinking back to
01:39:11 what will happen in 4 billion years to any of our descendants, they’ll be okay because the two disk
01:39:19 galaxies will merge. It’ll end up as a sort of amorphous elliptical galaxy. But the stars won’t
01:39:26 be much closer together than they are now. It’ll still be just twice as many stars in a structure
01:39:32 almost as big. And so the chance of another star colliding with our sun would still be very small.
01:39:41 Because there’s actually a lot of space between stars and planets.
01:39:45 Yes, the chance of a star getting close enough to affect our solar system’s orbit
01:39:49 is small. And it won’t change that very much. So you could be reassured.
01:39:53 A heck of a starry sky though. What would that look like?
01:39:57 Well, it won’t make much difference even to that actually. It’ll just be…
01:40:01 Wouldn’t that look kind of beautiful when you’re swirling? Oh, because it’s swirling so slowly.
01:40:05 Yeah, but they’re far away. So it’ll be twice as many stars in the sky.
01:40:10 Yeah, but the pattern changes in interesting ways.
01:40:12 Yeah, the pattern will change a bit. And there won’t be the Milky Way because the Milky Way
01:40:17 across the sky is because we are looking in the disk of our galaxy. And you lose that.
01:40:22 And because the disk will be so disrupted. And it’ll be a more sort of spherical distribution.
01:40:28 And of course, many galaxies are like that. And that’s probably because they have been through
01:40:33 mergers of this kind. If we survive four billion years,
01:40:36 we would likely be able to survive beyond that. Oh, yeah.
01:40:39 What’s the other thing on the horizon for humans in terms of the sun burning out,
01:40:45 all those kinds of interesting cosmological threats to our civilization?
01:40:51 Well, I think on the cosmological time scale, because it won’t be humans, because even if
01:40:57 evolution is no faster than Darwinian, and I would argue it will be faster than Darwinian
01:41:03 in the future, then we’re thinking about six billion years before the sun dies. So any
01:41:09 entities watching the death of the sun, if they’re still around, they’ll be as different
01:41:14 from much as we are from slime mold or something. And far more different still if they become
01:41:20 electronic. So on that time scale, we just can’t predict anything. But I think going back to
01:41:25 the human time scale, then we’ve talked about whether there’ll be people on Mars by the end
01:41:32 of a century. And even in these long perspectives, then indeed, this century is very special,
01:41:39 because it may see the transition between purely flesh and blood entities to those which are sort
01:41:45 of cyborgs. And that’ll be an important transition in the future.
01:41:51 But of course, the other importance, and this has been the theme of a couple of my older books,
01:41:55 is that this is the first century when one species, namely our species, has the future of
01:42:02 the planet in its hands. And that’s because of two types of concerns. One is that there are more
01:42:10 of us where more of us are living in the past, and the other is that there are more of us who are
01:42:16 living in the future. So those are two concerns. One is that there are more of us where more
01:42:23 demanding of energy and resources, and therefore we are for the first time changing the whole
01:42:30 planet through climate change, loss of biodiversity, and all those issues. This has never
01:42:37 happened in the past, because there haven’t been enough humans. So this is an effect that’s
01:42:43 now, and rightly so, because we’ve got to ensure that we leave a heritage that isn’t eroded or
01:42:51 damaged to future generations. And so that’s one class of threats.
01:42:55 But there’s another thing that worries me, perhaps more than many people seem to worry,
01:43:02 and that’s the threat of misuse of technology. And so this is particularly because technologies
01:43:11 empower even small groups of malevolent people, or indeed even careless people, to create some
01:43:21 effect which could cascade globally. And to take an example, a dangerous pathogen or pandemic,
01:43:30 I mean, my worst nightmare is that there could be some small group that can engineer a virus
01:43:42 to make it more variant or more transmissible than a natural virus. This is a gain of function
01:43:47 experiments which were done on the flu virus 10 years ago and can be done for others.
01:43:51 And of course, we now know from COVID 19 that our world is so interconnected that a disaster in one
01:44:02 part of the world can’t be confined to that part and will spread globally. So it’s possible for
01:44:08 a few dissidents with expertise in biotech could create a global catastrophe of that kind.
01:44:14 And also, I think we need to worry about very large scale disruption by cyber attacks and
01:44:21 in fact, I quote in one of my books, a 2012 report from the American Pentagon about the possibility
01:44:31 of a state level cyber attack on the electricity grid in Eastern United States, which is it could
01:44:38 happen. And it says at the end of this chapter that this would merit a nuclear response. This
01:44:45 is a pretty scary possibility. And that was 10 years ago. And I think now what would have needed
01:44:51 a state actor then could be done perhaps by a small group empowered by AI. And so there’s
01:44:57 obviously been an arms race between the cyber criminals and the cyber security people. Not
01:45:06 clear which side is winning. But the main point is that as we become more dependent on more
01:45:11 integrated systems, then we get more vulnerable. And so we have the knowledge, then the misuse of
01:45:21 that knowledge becomes more and more of a threat. And I’d say bio and cyber are the two biggest
01:45:28 concerns. And if we depend too much on AI and complex systems, then just breakdowns, it may be
01:45:37 that they break down. And even if it’s an innocent breakdown, then it may be pretty hard to mend it.
01:45:43 And just think how much worse the pandemic would have been if we’d lost the internet in the middle
01:45:48 of it. We’d be dependent more than ever for communication and everything else on the internet
01:45:55 and Zooms and all that. And if that had broken down, that would have made things far worse. And
01:46:01 those are the kinds of threats that we, I think, need to be more energized and politicians need to
01:46:07 be more energized to minimize. And one of the things I’ve been doing in the last year through
01:46:13 being a member of our part of our parliament is I have to instigate a committee to think more on
01:46:20 better preparedness for extreme technological risks and things like that. So they’re a big
01:46:26 concern in my mind that we’ve got to make sure that we can benefit from these advances but safely
01:46:36 because the stakes are getting higher and the benefits are getting great, as we know, huge
01:46:42 benefits from computers, but also huge downsides as well. And one of the things this war in Ukraine
01:46:50 has shown, one of the most terrifying things outside of the humanitarian crisis, is that at
01:46:58 least for me, I realized that the human capacity to initiate nuclear war is greater than I thought.
01:47:11 I thought the lessons of the past have been learned. It seems that we hang on the brink of
01:47:17 nuclear war with this conflict like every single day with just one mistake or bad actor or the
01:47:28 actual leaders of the particular nations launching a nuclear strike and all hell breaks loose. So
01:47:35 then add into that picture, cyber attacks and so on, that can lead to confusion and chaos. And then
01:47:43 out of that confusion, calculations are made such that a nuclear weapon is launched and then
01:47:56 you’re talking about, I mean, it directs probably 60, 70% of humans on Earth are dead instantly.
01:48:05 And then the rest, I mean, it’s basically 99% of the human population is wiped out in the period
01:48:14 of five years. Well, it may not be that bad, but it will be a devastation for civilization,
01:48:18 of course. And of course, you were quite right that this could happen very quickly because of
01:48:26 information coming in and there’s hardly enough time for human collected and careful thought.
01:48:34 And there have been recorded cases of false alarms. There’s several where there have been
01:48:41 suspected attacks from the other side. And fortunately, they’ve been really false alarm
01:48:48 soon enough, but this could happen. And there’s a new class of threats actually, which in our
01:48:53 center in Cambridge, people are thinking about, which is that the commander control system
01:49:00 of the nuclear weapons and the submarine fleet and all that is now more automated and could be
01:49:08 subject to cyber attacks. And that’s a new threat which didn’t exist 30 years ago. And so I think
01:49:16 indeed, we’re in a sort of scary world, I think. And it’s because things happen faster and human
01:49:26 beings aren’t in such direct and immediate control because so much is delegated to machines. And
01:49:32 also because the world is so much more interconnected, then some local event can cascade
01:49:40 globally in a way it never could in the past and much faster.
01:49:44 Yeah, it’s a double edged sword because the interconnectedness brings a higher quality of
01:49:54 life across a lot of metrics.
01:49:56 Yeah, it can do. But of course, there again, I mean, if you think of supply chains where we
01:50:02 get stuff from around the world, then one lesson we’ve learned is that there’s a trade off between
01:50:06 resilience and efficiency and it’s resilient to have an inventory in stock and to depend on local
01:50:16 supplies, whereas they’re more efficient to have long supply chains. But the risk there is that a
01:50:24 break in one link in one chain can screw up car production. This has already happened in the
01:50:30 pandemic. So there’s a trade off. And there are other examples. I mean, for instance, the other
01:50:35 thing we learned was that it may be efficient to have 95% of your hospital intensive care beds
01:50:42 occupied all the time, which has been the UK situation, whereas to do what the Germans do and
01:50:47 always keep 20% of them free for an emergency is really a sensible precaution. And so I think
01:50:53 we’ve probably learned a lot of lessons from COVID 19. And they would include rebalancing the
01:51:01 trade off between resilience and efficiency.
01:51:04 Boy, the fact that COVID 19, a pandemic that could have been a lot, a lot worse,
01:51:12 brought the world to its knees anyway.
01:51:15 It could be far worse in terms of its fatality rate or something like that, of course.
01:51:20 So the fact that that, I mean, it revealed so many flaws in our human institutions.
01:51:26 And I think I’m rather pessimistic because I do worry about the baractol, a small group
01:51:38 who can produce catastrophe. And if you imagine someone with access to the kind of equipment that’s
01:51:46 available in university labs or industrial labs, and they could create some dangerous pathogen,
01:51:52 then even one such person is too many. And how can we stop that? Because it’s true that you can
01:52:00 have regulations. I mean, academies are having meetings, et cetera, about how to regulate these
01:52:07 new biological experiments, et cetera, make them safe. But even if you have all these regulations,
01:52:13 then enforcing regulations is pretty hopeless. We can’t enforce the tax laws globally. We can’t
01:52:20 enforce the drug laws globally. And so similarly, we can’t readily enforce the laws against people
01:52:28 doing these dangerous experiments, even if all the governments say they should be prohibited.
01:52:33 And so my line on this is that all nations are going to face a big trade off between
01:52:40 three things we value, freedom, security, and privacy. And I think different nations will
01:52:52 make that choice differently. The Chinese would give up privacy and have certainly more security,
01:52:59 if not more liberty. But I think in our countries, I think we’re going to have to give up more
01:53:08 privacy in the same way. That’s a really interesting trade off. But there’s also something
01:53:15 about human nature here, where I personally believe that all humans are capable of good and
01:53:21 evil. And there’s some aspect to which we can fight this by encouraging people, incentivizing people
01:53:32 towards the better angels of their nature. So in order for a small group of people to create,
01:53:38 to engineer deadly pathogens, you have to have people that, for whatever trajectory took them
01:53:47 in life, wanting to do that kind of thing. And if we can aggressively work on a world
01:53:55 that sort of sees the beauty in everybody and encourages the flourishing of everybody in terms
01:54:03 of mental health, in terms of meaning, in terms of all those kinds of things, that’s one way
01:54:08 to fight the development of weapons that can lead to atrocities.
01:54:14 RL Yes, and I completely agree with that and to reduce the reason why people feel embittered.
01:54:19 But of course, we’ve got a long way to go to do that. Because if you look at the present world,
01:54:26 nearly everyone in Africa has reason to feel embittered because their economic development
01:54:34 is lagging behind most of the rest of the world. And the prospects of getting out of
01:54:39 the poverty trap is rather bleak, especially as the population grows. Because for instance,
01:54:46 they can’t develop like the Eastern Tigers by cheap manufacturing, because robots have taken
01:54:50 that over. So they naturally feel embittered by the inequality. And of course, what we need to have
01:54:59 is some sort of mega version of the Marshall Plan that helped Europe in the post World War II era
01:55:06 to enable Africa to develop. That would be not just an altruistic thing for Europe to do,
01:55:11 but in our interest because otherwise, those in Africa will feel massively disaffected.
01:55:20 And indeed, it’s a manifestation of the excessive inequalities, the fact that the
01:55:24 2000 richest people in the world have enough money to double the income of the bottom billion.
01:55:30 And that’s an indictment of the ethics of the world. And this is where my friend Stephen Pinker
01:55:39 and I have had some contact. We wrote joint articles on bio threats and all that. But he
01:55:46 writes these books, being very optimistic about quoting figures about how life expectancy has gone
01:55:54 up, infant mortality has gone down, literacy has gone up, and all those things. And he’s quite
01:55:58 right about that. And so he says the world’s getting better. Do you disagree with your
01:56:04 friends, Stephen Pinker? Well, I mean, I agree with those facts. But I think he misses out part
01:56:11 of the picture. Because there’s a new class of threats, which hang over us now, which didn’t
01:56:19 hang over us in the past. And I would also question whether we have collectively improved
01:56:24 our ethics at all. Because let’s think back to the Middle Ages. It’s true that, as Pinker says,
01:56:30 the average person was in a more miserable state than they are today, on average. For all the
01:56:37 reasons he quantifies, that’s fine. But in the Middle Ages, there wasn’t very much that could
01:56:44 have been done to improve people’s lot in life because of lack of knowledge and lack of science,
01:56:51 etc. So the gap between the way the world was, which was pretty miserable, and the way the world
01:56:57 could have been, which wasn’t all that much better, was fairly narrow. Whereas now, the gap
01:57:03 between the way the world is and the way the world could be is far, far wider. And therefore, I think
01:57:09 we are ethically more at fault in allowing this gap to get wider than it was in medieval times.
01:57:18 And so I would very much question and dispute the idea that we are ethically in advance of
01:57:26 our predecessors collectively. That’s a lot of interesting hypotheses in there. It’s a fascinating
01:57:33 question of how much is the size of that gap between the way the world is and the way the world
01:57:39 could be is a reflection of our ethics. Or maybe sometimes it’s just a reflection of a very large
01:57:44 number of people. Maybe it’s a technical challenge too. It’s not just… Well, of our political
01:57:51 systems. And we’re trying to figure this thing out. There’s 20th century, tried this thing that
01:57:58 sounded really good on paper of collective, the communism type of things. And it’s like,
01:58:05 turned out at least the way that was done there, that leads to atrocities and the suffering and
01:58:10 the murder of tens of millions of people. Okay, so that didn’t work. Let’s try democracy.
01:58:16 And that seems to have a lot of flaws, but it seems to be the best thing we got so far.
01:58:20 So we’re trying to figure this out as our technologies become more and more powerful,
01:58:25 have the capacity to do a lot of good to the world, but also unfortunately have the capacity
01:58:30 to destroy the entirety of the human civilization. And I think it’s social media generally,
01:58:35 which makes it harder to get a sort of moderate consensus because in the old days when people got
01:58:43 their news filtered through responsible journalists in this country, the BBC and the
01:58:49 main newspapers, et cetera, they would muffle the crazy extremes. Whereas now, of course,
01:58:56 they’re on the internet. And if you click on them, you get something still more extreme.
01:59:00 And so I think we are seeing a sort of dangerous polarization, which I think is going to make all
01:59:06 countries harder to govern. And that’s something which I’m pessimistic about.
01:59:09 RL So to push back, it is true that brilliant people like you highlighting the limitations
01:59:15 of social media is making them realize the stakes and the failings of social media companies,
01:59:22 but at the same time, they’re revealing the division. It’s not like they’re creating it,
01:59:26 they’re revealing it in part. And so that puts a lot of, that puts the responsibility
01:59:34 into the hands of social media and the opportunity in the hands of social media
01:59:38 to alleviate some of that division. So it could in the long arc of human history result. So bringing
01:59:45 some of those divisions and the anger and the hatred to the surface so that we can talk about
01:59:52 it. And as opposed to disproportionately promoting it, actually just surfacing it so we can get over
01:59:57 it. Well, you’re assuming that the fat cats are more public spirited than the politicians.
02:00:02 And I’m not sure about that.
02:00:03 RL I think there’s a lot of money to be made in being publicly spirited. I think there’s a lot of
02:00:10 money to be made in increasing the amount of love in the world, despite the sort of public perception
02:00:17 that all the social media companies heads are interested in doing is making money.
02:00:23 I think that may be true, but I just personally believe people being happy
02:00:31 is a hell of a good business model. And so making as many people happy, helping them flourish in a
02:00:39 long term way, that’s a good way to make money.
02:00:42 RL Well, I think on the other hand, guilt and shame are good motives to make you behave better
02:00:47 in the future. That’s my experience.
02:00:49 RL From maybe in the political perspective, certainly it’s the case. But it does make sense
02:00:56 now that we can destroy ourselves with nuclear weapons, with engineered pandemics and so on,
02:01:02 that the aliens would show up. If I had a leadership position, maybe as a scientist
02:01:14 or otherwise in an alien civilization, and I would come upon Earth, I would try to watch from
02:01:22 a distance, do not interfere. And I would start interfering when these life forms start
02:01:31 becoming quite, have the capacity to be destructive. And so, I mean, it is an interesting
02:01:38 question when people talk about UFO sightings and all those kinds of things that at least…
02:01:43 RL These are benign aliens you’re thinking of.
02:01:45 RL Benign, yes. I mean, they benign, almost curious, almost, partially, as with all curiosity,
02:01:55 partially selfish to try to observe, is there something interesting about this particular
02:02:00 evolutionary system? Because I’m sure even to aliens, Earth is a curiosity.
02:02:06 RL Yeah. Well, it’s in its very special stage.
02:02:09 RL It’s very special. Perhaps it’s very short.
02:02:12 RL This century is very special among the 45 million centuries the Earth experienced already.
02:02:17 So it is a very special time where they should be specially interested. But I think going back
02:02:22 to the politics, the other problem is getting people who have short term concerns to care
02:02:31 about the long term. By the long term, I now mean just looking 30 years or so ahead. I
02:02:38 know people who’ve been scientific advisors to governments and things, and they may make
02:02:43 these points, but of course, they don’t have much traction because as we know very well,
02:02:48 any politician has an urgent agenda of very worrying things to deal with. And so they
02:02:54 aren’t going to prioritize these issues, which are longer term and less immediate, and don’t
02:03:01 just concern their constituents, they concern distant parts of the world. And so I think
02:03:08 what we have to do is to enlist charismatic individuals to convert the public, because
02:03:17 if the politicians know the public care about something, climate change as an example, then
02:03:25 they will make decisions which take cognizance of that. And I think for that to happen, then
02:03:34 we do need some public individuals who are respected by everyone, and to have a high
02:03:42 profile. And in the climate context, I would say that I’ve mentioned four very disparate
02:03:48 people who’ve had such a big effect in the last few years. One is Pope Francis, the other is
02:03:54 David Attenborough, the other is Bill Gates, and the other is Greta Thornberg. And those
02:03:58 four people have certainly had a big shift in public opinion, and even changed the rhetoric
02:04:07 of business, although how deep that is, I don’t know. But politicians can’t let these
02:04:14 issues drop down off the agenda if there’s a public clamor, and it needs people like that
02:04:21 to keep the public clamor going.
02:04:23 To push back a little bit, so those four are very interesting, and I have deep respect
02:04:27 for them. They have, except David Attenborough, David Attenborough is really, I mean, everybody
02:04:33 loves him. I can’t say anything. But Bill Gates and Greta, that also has created a lot
02:04:40 of division. And this is a big problem, so it’s not just charismatic. I put that responsibility
02:04:46 actually on the scientific community and the politicians. So we need the charismatic leaders,
02:04:58 and they’re rare. When you look at human history, those are the ones that make a difference.
02:05:03 Those are the ones that, not deride, they inspire the populace to think long term. The
02:05:13 JFK will go to the moon in this decade, not because it’s easy, but because it is hard.
02:05:20 There’s no discussion about short term political gains or any of that kind of stuff in the
02:05:30 vision of going to the moon, or going to Mars, or taking on gigantic projects, or taking
02:05:37 on world hunger, or taking on climate change, or the education system, all those things
02:05:42 that require long term significant investment. That requires…
02:05:47 But it’s hard to find those people. And incidentally, I think another problem, which is a downside
02:05:53 of social media, is that of younger people I know, the number who would contemplate a
02:06:01 political career has gone down because of the pressures on them and their family from
02:06:07 social media. It’s a hell of a job now. And so I think we are all losers because the quality
02:06:14 of people who choose that path is really dropping. And as we see by the quality of those who
02:06:24 are in these compositions.
02:06:25 That said, I think the silver lining there is the quality of the competition actually
02:06:31 is inspiring because it shows to you that there’s a dire need of leaders, which I think
02:06:39 would be inspiring to young people to step into the fold. I mean, great leaders are not
02:06:43 afraid of a little bit of fire on social media. So if you have a 20 year old kid now, 25 year
02:06:51 old kid is seeing how the world has responded to the pandemic, seeing the geopolitical division
02:06:57 over the war in Ukraine, seeing the brewing war between the West and China. We need great
02:07:03 leaders and there’s a hunger for them and the time will come when they step up. I believe
02:07:11 that. But also to add to your list of four, he doesn’t get enough credit. I’ve been defending
02:07:16 him in this conversation, Elon Musk, in terms of the fight in climate change. But he also
02:07:22 has led to a lot of division, but we need more David Edinburgh.
02:07:27 Yeah, no, no. I mean, I’m a fan. Definitely. I mean, I’ve heard him described as a 21st
02:07:33 century Brunel for his innovation and that’s true. But whether he’s an ethical inspiration,
02:07:40 I don’t know.
02:07:41 Yeah, he has a lot of fun on Twitter. Well, let me ask you to put on your wise sage hat.
02:07:50 What advice would you give to young people today? Maybe they’re teenagers in high school,
02:07:56 maybe early college. What advice would you give to a career or have a life they can be
02:08:04 proud of?
02:08:05 Yes. Well, I’d be very diffident, really, about offering any wisdom. But I think they
02:08:14 should realise that the choices they make at that time are important. And from the experience
02:08:27 I’ve had with many friends, many people don’t realise that opportunities open until it’s
02:08:33 too late. They somehow think that some opportunities are only open to a few privileged people and
02:08:38 they don’t even try and that they could succeed. But if I focus on people working in some profession
02:08:48 I know about, like science, I would say pick an area to work in where new things are happening,
02:08:56 where you can do something that the old guys never had a chance to think about. Don’t go
02:09:02 into a field that’s fairly stagnant because then there’s nothing much to do or you’ll
02:09:07 be trying to tackle the problems that the old guys got stuck on. And so I think in science,
02:09:13 I can give people good advice that they should pick a subject where there are exciting new
02:09:19 developments. And also, of course, something which suits their style because even within
02:09:24 science, which is just one profession, there’s a big range of style between the sort of solitary
02:09:29 thinker, the person who does field work, the person who works in a big team, et cetera,
02:09:34 and whether you like computing or mathematical thought, et cetera. So pick some subject that
02:09:40 suits your style and where things are happening fast. And be prepared to be flexible. That’s what
02:09:46 I’d say, really. Keep your eyes open for the opportunity throughout, like you said. Go to
02:09:51 a new field. Go to a field where new cool stuff is happening. Just keep your eyes open.
02:09:56 Yes, that’s patitudinous. But I think most of us, and I include myself in this, didn’t realize
02:10:01 this sort of thing isn’t too late.
02:10:05 Yeah, I think this applies way beyond science. What do you make of this finiteness of our life?
02:10:13 Do you think about death? Do you think about mortality? Do you think about your mortality?
02:10:18 And are you afraid of death?
02:10:20 Well, I mean, I’m not afraid because I think I’m lucky. I feel lucky to have lasted as long as I
02:10:25 have and to have been fairly lucky in my life in many respects compared to most people. So I feel
02:10:35 very fortunate. This reminds me of this current emphasis on living much longer, the so called
02:10:44 Altos Laboratories, which have been set up by billionaires. There’s one in San Francisco,
02:10:53 one in La Jolla, I think, and one in Cambridge. And they’re funded by these guys who when young
02:11:03 wanted to be rich, and now they’re rich, they want to be young again. They won’t find that quite so
02:11:07 easy. And do we want this? I don’t know. If there was some elite that was able to live much longer
02:11:14 than others, that would be a really fundamental kind of inequality. And I think if it happened
02:11:23 to everyone, then that might be an improvement. It’s not so obvious. But I think for my part,
02:11:32 I think to have lived as long as most people and had a fortunate life is all I can
02:11:39 expect and a lot to be grateful for. Those are all past issues.
02:11:44 Well, I am incredibly honored that you sit down with me today. I thank you so much for life,
02:11:51 of exploring some of the deepest mysteries of our universe and of our humanity and thinking
02:11:57 about our future with existential risks that are before us. It’s a huge honor,
02:12:02 Martin, that you sit with me and I really enjoyed it.
02:12:06 Well, thank you, Lex. I thought we couldn’t go on for as long as this,
02:12:09 but we could have gone on much longer.
02:12:11 Exactly. Thank you so much. Thank you for listening to this conversation with Martin
02:12:16 Rees. To support this podcast, please check out our sponsors in the description. And now,
02:12:21 let me leave you with some words from Martin Rees himself.
02:12:24 I’d like to widen people’s awareness of the tremendous time spent lying ahead for our planet
02:12:30 and for life itself. Most educated people are aware that we’re the outcome of nearly 4 billion
02:12:37 years of Darwinian selection, but many tend to think that humans are somehow the culmination.
02:12:44 Our sun, however, is less than halfway through its lifespan. It will not be humans who watch
02:12:51 the sun’s demise 6 billion years from now. Any creatures that then exist will be as different
02:12:58 from us as we are from bacteria or amoeba. Thank you for listening, and hope to see you next time.