In this episode of the podcast, I catch up with astrophysicist and author of The Big Bang Theory, Brian Enthoven. We talk about his new podcast, his upcoming world tour, and why he thinks we should all be asking the big questions about the universe that we all have been asking for a long time: why are we here, how did the universe begin, and what does it mean to be human in a possibly infinite universe? And how can we make sense of it all? We also talk about some of the weirdest things we've ever heard about the Big Bang and why it's so important to know about it. And, of course, we have a quiz! If you like science and podcasts, you'll love this episode! Subscribe to Extraterrestrial life! Want to become a Friend of the Dark Side Up podcast? Subscribe, rate and review our new show on Apple Podcasts and become a patron? Learn more about your ad choices and get 10% off the first month with discount code: CRYPTOMILLION at checkout. We'll be giving out $10 off your first month, and we'll give you 5% off for the rest of the year if you leave a review on iTunes, too! Thanks for supporting the show! Brian's new book "The Big Bang" is out now! It's out in paperback and hardcover edition of his new book, The Universe Explores It's Big Bang: The Ultimate Guide to the Biggest Thing You'll Never Hear About It's Not Big Enough! is out on Amazon Prime, so you can read it on Kindle, Kindle, iBook, Paperwhite, Paperback, and Audible, and more! Best of all, it's Free, it'll Have It all, you get a copy of it on the Kindle Fire HDX, and it'll be on VSCode, too, you can watch it on VHS, and subscribe to it on Audible and subscribe on the Podcoin, and all other good ol' Audible? It'll also be on the App, too? Thank you for listening to it all, Brian will have access to all the world's Best Podcasts, and Brian will be getting all the best of the best podcasting and social media access, and so much more. You'll get access to the latest in the best vlogs, you won't be able to access all of that?
00:00:54.000It starts next week in the UK. And then we go everywhere from the South Island of New Zealand all the way to the Arctic Circle, to Svalbard, which is the furthest north that you can go on a commercial aircraft.
00:01:58.000So it's really about showing the size and scale of the universe, but addressing those questions that I think everybody has about what does it mean to be human, this tiny little finite life that we lead in a possibly infinite universe.
00:02:13.000Well, it's incredibly exciting to me that there's a giant audience for this and that what Neil deGrasse Tyson had been doing and what a lot of public touring intellectuals are doing now, they're doing these giant theaters and these people are coming out to see these shows and we're realizing that there's,
00:02:30.000I hate to use the term market for this, but there's a demand for this and there's a lot of people who are incredibly fascinated by this and it's spreading information, it's spreading knowledge.
00:02:41.000Yeah, I mean, in the UK particularly, I mean, Wembley Arena, for example, you know, you're talking about 10,000 people, 12,000 people in these shows.
00:02:49.000And you're right, they are coming, although, you know, they're big shows, spectacular screens and all that, they're coming for, to think, they're coming to hear about what we know about the universe and nature.
00:03:03.000I'm not surprised people are interested because these are questions that everybody asks.
00:04:33.000I challenge anyone to be able to picture that.
00:04:36.000But it is the reality that we've observed.
00:04:40.000We haven't counted all two trillion, by the way.
00:04:42.000We have a thing called the Sloan Digital Sky Survey, which maps the positions of galaxies.
00:04:47.000So you know how much of the sky you've surveyed, and you know how many galaxies you've counted, and then you can spread that across the wider universe.
00:04:56.000And you get this picture of a vast and possibly infinite universe.
00:05:00.000We know that the universe, or very strongly suspect, that the universe is much bigger than the piece we can see.
00:05:07.000So we have good reason to think that's the case.
00:05:10.000Whether it's infinite or not is another question.
00:05:12.000And then that goes to your, you know, can you picture infinity?
00:06:21.000The eternal universe, if there was an eternal universe, does that negate the theory of the Big Bang or does it mean that there's a constant cycle of Big Bangs and then expansion and then recompression?
00:06:54.000Or some of the other theories, there's a theory called eternal inflation, which is a theory that And it's actually the most popular theory, I think, at the moment, for what happened, for why the Big Bang is the way that it is.
00:07:05.000Because it's got some very special features, the Big Bang, which we could talk about.
00:07:08.000But inflation is the idea that space, space-time, was around before the Big Bang, and it was expanding extremely fast.
00:07:16.000There was doubling in size in the most popular of these theories, every 10 to the minus 37 seconds, which is 0.00000 with 37 knots, one of a second.
00:07:26.000So it's an unimaginably fast expansion.
00:07:29.000And then the idea is that draws to a close, so it quite naturally sort of dies away and the expansion slows down.
00:07:35.000And all the energy that was taken that was causing that expansion sort of gets dumped into space and heats it up and makes particles, and that's what we call the Big Bang.
00:07:44.000And those theories, the slight extension to those, say that that slowing down just happens in little patches.
00:07:52.000So most of the universe, the overwhelming majority of the universe, is still inflating at that insane speed.
00:08:00.000And just little patches stop and they're big bangs.
00:08:04.000So you get multiple universes, a multiverse, it's called the inflationary multiverse, and we are in one of those bubbles.
00:08:11.000And that's one of the more popular theories.
00:08:15.000Right now, I'm aware of what you're saying.
00:08:18.000I can sort of visualize it in some sort of a graphic form, but it's incomprehensible.
00:08:25.000My mind doesn't have the capacity to expand...
00:08:30.000This sense of distance and size to that grasp.
00:08:34.000Is this because of just the way we evolved?
00:08:36.000We evolved here on Earth to deal with the space that's in front of us, and now over the course of industrial civilization and education, we're now grasping these concepts that are so Alien to the reality,
00:08:52.000the tangible reality that we exist in every day?
00:08:57.000You know, even very simple things, like you go back to the Greeks, so Aristotle and the great, you know, very clever people, but they thought the Earth was at the center of the universe.
00:09:38.000And actually, it's quite a deep thought to understand why it doesn't feel that we're moving.
00:09:45.000You have to go all the way to Einstein, really, for someone to take that very seriously.
00:09:50.000And what he said, actually, he said, well, there's a great little explanation in Stephen Hawking's Brief History of Time about this, that the idea that you can't tell whether you're moving or not demolishes the notion of absolute space.
00:10:03.000So if we think about space, if I said space to you or most people, I suppose, you'd think the way that Newton did, of a big box within which things happen.
00:10:11.000And that's got to be, that's a natural picture of space and the universe, isn't it?
00:10:15.000It's a thing in which all the planets and galaxies are placed.
00:10:19.000But in The Brief History of Time, Hawking says, well, imagine bouncing a ball.
00:10:23.000So we bounce a ball on the table now, a tennis ball.
00:11:53.000We could look at the decay of a radioactive nucleus or some electricity and magnetism or bounce a ball, have a pendulum, whatever it is, and there's no experiment you can do to tell you whether you're moving or not.
00:12:04.000Therefore, that concept has no meaning because you can't measure it.
00:12:10.000And that's led Einstein to relativity.
00:12:13.000So that's the basis of general relativity, which is our best theory of the universe.
00:12:19.000Now, why is it that we think that the known universe is larger than we can observe?
00:12:27.000Well, one point is that it's expanding and we always see the same radiation out there, the glow of the Big Bang.
00:12:41.000One, from the theory of inflation, the best way to explain the universe, the properties that we see, is that it's very much bigger than the piece we can see.
00:12:55.000So, for example, We measure space to be what's called flat.
00:13:00.000I don't even have to say what's called flat.
00:13:17.000It can be flat like a tabletop or it could be curved like a sphere or it could be curved in the opposite direction, sort of like a saddle or a bowl.
00:13:26.000And when we measure it, we see it's absolutely flat.
00:13:29.000And that's a very unusual thing for it to be like.
00:13:34.000It requires, because what Einstein's theory says is that the shape of space, that the curvature of space is determined by the stuff that's in it.
00:13:43.000That's basically Einstein's theory of general relativity.
00:13:46.000Put stuff in space and it curves it and bends it and warps it and stretches it and so on.
00:13:51.000And what we find is that there's precisely the right amount of stuff in the universe to have a completely flat universe.
00:13:59.000And the explanation, the most favoured explanation for that, is the universe is way bigger than the piece we can see.
00:14:04.000And so it's like looking at a piece of the Earth.
00:14:06.000If you look at a little one mile square of the Earth, then it's flat.
00:14:13.000You have to look at big distances, kind of a border, the radius of the Earth, you know, bigger than one kilometre anyway, or one mile square.
00:14:20.000To see that actually you're on a curved surface.
00:14:23.000And that's one of the ideas about the universe and why it appears to be the way that it is.
00:16:07.000We can look at the most distant light we can see, which is something called the cosmic microwave background radiation, which is...
00:16:16.000If you imagine looking out, if you look at the Andromeda galaxy, which we can see with the naked eye here in LA, you can see that.
00:16:23.000It's the most distant object you can see with the naked eye.
00:16:26.000And it's about two million light years away or so, which means the light took two million years to get to us.
00:16:32.000So it's a long way away, but it's very big.
00:16:35.000So as you look further out into the universe, to more and more distant galaxies, you're looking further back in time because you look at something that's A billion light years away, then the light took a billion years to get to us.
00:16:46.000So you see it as it was a billion years in the past.
00:16:48.000And we can actually look so far out that we can see almost back to 13.8 billion years ago, which is very close to the Big Bang.
00:16:58.000So we can look to light that began its journey before there were galaxies.
00:17:03.000And that's the oldest light in the universe, which is, by the way, one of the pieces of evidence when people say, I don't believe in the Big Bang.
00:17:17.000That light, it turns out that there are structures or ripples in that light, which we can use as a ruler.
00:17:25.000So quite literally, as a ruler on the sky.
00:17:28.000And then because that light's been traveling through the universe, we can see how that rule has been distorted as the light has traveled through space.
00:17:36.000And so we can infer whether space is flat or curved or how it warps, if you like, just from that measurement.
00:18:00.000Well, before that time, the universe was so hot that atoms couldn't form.
00:18:05.000So you had a soup of electrically charged particles.
00:18:08.000It was just too hot for electrons to go into orbit around nuclei.
00:18:12.000So the universe was opaque to light, so you just couldn't.
00:18:15.000It was almost like a big glowing star, if you like.
00:18:19.000And then when it was expanding, it cooled past the point where the atoms could form.
00:18:23.000And at that point, it becomes transparent, really almost instantly in a cosmic timescale.
00:18:29.000And so the light could then travel in straight lines through the universe, and we can see that light.
00:18:34.000So we see the light from that time, but further back than that, it's opaque, so you can't see past that with light.
00:18:42.000But you can, potentially, with gravitational waves, which is this measurement that got the Nobel Prize a couple of years ago, the LIGO experiment here in the United States.
00:18:52.000And that looks for ripples in the fabric of space and time.
00:18:56.000And in principle, if we had a big enough detector, you could see the ripples from the Big Bang.
00:19:01.000So you could take an image of the Big Bang in gravitational waves, which would be...
00:19:07.000But you need an enormous space-based detector that we're not going to build anytime soon.
00:19:12.000Now obviously this is all through equipment and technology that's been invented over the last few hundred years and perfected.
00:19:19.000Is it possible that things could get better and you could get some ability to detect things even in a far more distant way?
00:19:28.000Yeah, I mean, the gravitational waves are incredible.
00:19:31.000I mean, Einstein predicted them in 1915. Never thought they'd be detected because you need such a hyper...
00:20:39.000So that technology is incredible because the change in length I can't remember the exact number, but it's way, way, way less than the diameter of an atomic nucleus.
00:22:22.000So they are stars at the end of their life.
00:22:25.000Very bigger than the Sun, more massive than the Sun, but they run out of their fuel and they start to collapse because gravity squashes them.
00:22:32.000And if they're sufficiently massive, then there's nothing that can stop the collapse.
00:22:37.000And so they collapse, as far as we know, to a point, essentially an infinitely dense point.
00:22:44.000We don't really know what happens, we don't know what happens right in the middle.
00:22:48.000But they collapse to such an extent that there's a region around it from which light can't escape.
00:24:07.000And when it collapses, there's a sort of a pressure, a force, if you like, which is caused by the fact that electrons don't like to be very close to each other.
00:24:20.000So it's called the Pauli Exclusion Principle.
00:24:22.000But essentially what happens is that as they get squashed closer and closer together, they move faster and faster to get out of each other's way, if you like.
00:24:31.000And that makes a force which holds them up.
00:24:34.000And so that creates what's called a white dwarf star.
00:24:57.000So if it's massive enough that it overwhelms the electron thing, then the electrons sort of crush into protons and turn into neutrons, and the whole thing starts again.
00:26:04.000The first one that was discovered was called LGM-1 because they spin very fast.
00:26:10.000And it was called LGM-1 because it's a very regular pulse and they thought it was little green men.
00:26:15.000So they called it, kind of jokingly, Little Green Men one.
00:26:21.000We've seen that there's one called the Crab Pulsar, which is in the Crab Nebula, which we saw the supernova explosion.
00:26:27.000So that's when one of these stars explodes at the end of its life and then collapses to form a neutron star.
00:26:32.000And we saw that in 1054 AD. Wasn't there some speculation that our solar system at one point was a binary star system and that one of those stars had become a dwarf?
00:27:46.000It's one of those, it is a possibility that there's something out there.
00:27:49.000The speculation was that there's something out there, correct me if I'm wrong, something called a galactic shelf, like that it gets to a certain space and it indicates that there's something far larger out there.
00:28:09.000I mean, there are some sort of suggestions there's another planet out there, a big planet, for example.
00:28:15.000But you're right, there can be stuff orbiting way beyond the Kuiper Belt.
00:28:20.000And we're talking, you know, a light year away or something like that now.
00:28:24.000It's interesting because it's incomprehensible, the distance, right, in our minds, how far that must be out past what we used to call Pluto.
00:28:31.000But for whatever reason, that becomes more interesting because it's in our neighborhood.
00:28:37.000Whereas if they find some distant star system and it might have a planet that's similar to Earth, that doesn't seem as compelling for whatever weird reason.
00:28:48.000Yeah, I mean, I think the planets around Alpha Centauri, Proxima Centauri, which are the closest stars, it seems like there are planets around those now.
00:28:57.000And I think that was interesting, because we could conceive of going there.
00:29:01.000And there was this idea, Stephen Hawking, actually, and some others, Before he died, he had this idea called Breakthrough Starshot, which is the idea to send a little probe out to the Alpha Centauri system.
00:29:13.000And I think in their view, Yuri Milner as well, the entrepreneur, wanted to do that.
00:29:21.000And I think it's something like 100 years travel time or something with our current technology.
00:29:27.000And they pointed out that we don't do that now.
00:29:29.000We don't think 100 years in the future.
00:29:31.000But if you go back when people were building cathedrals, people used to routinely start projects that would take 100 years to bear fruit.
00:29:42.000And that then becomes fascinating, I think, because then you've got a solar system, another solar system that you could go and visit conceivably.
00:30:40.000If you can send a little robot spaceship there, you can send a crude spaceship there.
00:30:44.000I'm of the opinion as time goes on and augmented and virtual reality gets better and better that it doesn't really totally make sense unless we're talking about colonizing someplace to send biological life to another planet.
00:30:59.000If we can send some probe that doesn't have to worry about You know, the biology being affected by radiation or by the speed of travel or even by food.
00:31:09.000We can send something out there and almost be there by virtue of, you know, goggles, virtual reality goggles or something else.
00:31:21.000In science at the moment, space science, we have this debate a lot, actually, because, of course, space probes like Curiosity that's on Mars at the moment, that's really cheap compared to sending people to Mars.
00:31:33.000And so quite often the scientists who want to find out about the world will say, well, we should spend it on robots.
00:31:41.000I think crude space exploration is, in some ways, I mean, it's clearly true at the moment that humans can do more than robots, so we can explore the place better.
00:31:53.000But I think it has to be, it's about something else.
00:31:57.000I mean, it's about, and it's not only, it's about living and working off the planet, which I think is quite a persuasive argument, actually.
00:32:07.000We've already industrialized near-Earth orbit, so it's already a multi-billion dollar industry, you know, communication satellites and weather satellites, GPS, whatever.
00:32:17.000And so learning to live and work in space is, I think, a natural extension of our Of our civilization.
00:32:24.000Plus the fact if you talk to Elon or Jeff Bezos, they point out that the amount of resources available just slightly above our heads is vast.
00:32:33.000And so I remember I talked to Jeff Bezos actually once and he thinks really simply and he said, for example, in the asteroid belt, there's enough metal, I think, to build a skyscraper.
00:32:58.000So you could almost imagine trying to zone the earth residential at some point in the future to protect the planet and do your heavy industry off the planet, for example.
00:33:08.000And it sounds like science fiction, except that...
00:33:11.000Now, SpaceX and Blue Origin, those people have got reusable rockets.
00:33:15.000So suddenly the economics becomes sensible.
00:33:32.000It's not about gathering scientific information.
00:33:34.000It's about a frontier and all the benefits that come from operating as a civilization on a frontier, which we've lost on the Earth because there is no frontier left.
00:34:10.000If we just want to find out stuff, then you send robots.
00:34:13.000But as far as expanding actual civilization and bringing it to another place, one of the things that freaks me out is people get depressed about living in Seattle.
00:36:00.000So it would still have a significant weakening effect.
00:36:03.000Like if you went to Mars and then somehow or another in the future they were able to get back to Earth, your body would have a real problem with that, right?
00:36:56.000So you could go there, and at the bottom, the atmospheric pressure's so high that you could just about have liquid water occasionally on the floor of that crater.
00:38:10.000So it would be a different kind of lightsaber.
00:38:12.000The only point I was making is that photons, particles of light, can bounce off each other.
00:38:17.000So we see that in really high energy experiments in particle accelerators, we can collide photons together.
00:38:23.000So my point was a bit of a pedantic physicist one, because it is true that light can bounce off, it can hit light, but very, very high energy.
00:38:34.000But when they press that button, it goes to a certain distance.
00:39:59.000I could go warp speed in this Millennium Falcon and travel the speed of light, but for whatever reason, these lasers are so slow that you could duck out of the way of them?
00:41:15.000I read that they just – someone just found an interview, didn't they, the other day where he explained the ending of 2001. I didn't see that.
00:41:24.000And it was kind of a really simple version of it.
00:41:27.000He just said, well, the super intelligent beings take him in and put him in a zoo, basically, and watch him grow old and then send him back to the earth as a super being.
00:41:39.000That's the worst explanation at the end of 2001 I've ever heard.
00:42:36.000You know, because I think it is, you're right, it's a form that you can let your imagination wander and address things without restriction, I think.
00:43:09.000But I feel like Ridley Scott's original Alien is probably one of the greatest horror science fiction movies of all time and one of my all-time favorite movies.
00:43:18.000But I really like the newer ones as well.
00:43:20.000I like Prometheus and I really like Covenant, the last one.
00:45:26.000It's about the sun as a god in some ways.
00:45:29.000So it's about our response to the power of nature.
00:45:31.000And it's about deifying this thing and worshipping it and how ultimately you go mad.
00:45:37.000If you remember the film, there's Pimbacker, who's the first captain that went to the...
00:45:41.000Captain the first mission to go and restart the sun, which is the mad bit, but then became a religious fundamentalist, essentially, and then decided...
00:45:49.000It's a fascinating idea that he decides to bring meaning to his life.
00:45:54.000He will become the last, last man, the last human.
00:46:08.000So he stays there waiting for the second ship.
00:46:10.000And I like those ideas that, you know, what's your reaction to the power of nature?
00:46:17.000One of the things I do in my shows, I'm not being a commercial person, I've just thought of it.
00:46:21.000One of the great things about cosmology is that it is terrifying in the truest sense of the word.
00:46:27.000I mean, we talked a bit about the size and scale of the universe and black holes colliding and those things.
00:46:32.000It is very frightening, but also I think the act of trying to understand our place in nature and the size and scale of the universe and our tiny presence within it is valuable.
00:46:51.000So that you can be terrified but also inspired and interested.
00:46:56.000And it's part of, if you want to find If you want to ask questions about what it means to be human and means to be alive, then I think you find the answers in confronting that reality, which is that we live in a terrifyingly vast universe, powers in the universe that we cannot comprehend,
00:47:26.000And it is really interesting that we need that suspension of disbelief in order to sort of make a film on space.
00:47:34.000You almost have to go, well, this isn't really how it would be, but this is how you have to make it in order to fit it into a two-hour movie.
00:47:57.000I always wanted to ask about their concept of propulsion, that almost like space would be flat and you would fold space over and you would intersect those two points and you would be able to travel vast distances instantaneously, right?
00:48:12.000I'm doing a terrible job of explaining it, I'm sure.
00:48:15.000Is that a concept that people have actually considered?
00:48:18.000Yeah, in general relativity, I should say what it is, Einstein's theory of general relativity is our best theory of space and time.
00:48:28.000And so it really is, as we talked about before, you imagine space and time as a sheet, just imagine it as a thing, literally a sheet surface.
00:48:39.000And all the theory says is that if you put matter and or energy into that, then it curves it and distorts it and it can stretch it and make it shrink.
00:48:48.000And so it's the response of space and time to matter and energy.
00:48:52.000So the simplest version would be the Sun.
00:48:56.000So you put a big spherical ball of stuff in there and it warps space and time such that the nice straight lines, something just travelling minding its own business through that warp space, turns into an orbit.
00:49:08.000And that's why you can actually kind of see things that are behind the Sun?
00:49:12.000So light bends around the Sun because it's just traveling through the curved space.
00:49:17.000The Earth goes around the Sun because it's just rolling, minding its own business through the curved space.
00:49:23.000So an example would be, you might say, well, how does curved space, how can that give rise to something that looks like a force, which is gravity?
00:49:32.000So the best analogy I know of is to think of walking around on the surface of the Earth.
00:49:36.000So if you stand on the equator of the Earth with your friend and you say, we're going to walk due north.
00:49:42.000So we're going to set off, let's say we're a thousand miles apart on the equator and we're going to walk due north.
00:50:20.000So all you have to do, those folded kind of geometries, is you have to try and specify where you would put the matter and what kind of stuff you'd put there to make the geometry fold in that way.
00:50:35.000And you can do it so you can write down that geometry.
00:50:39.000It's called a warp drive geometry, I think it's in textbooks.
00:50:43.000So you can do that to have a warp drive.
00:50:47.000The question becomes, what sort of stuff Would you have to actually put into the real universe to make it warp in that way?
00:50:55.000And it usually turns out that it's the kind of stuff that doesn't exist.
00:52:38.000So you could go all the way around the edge, or you could take the shortcut.
00:52:41.000So you can do that in Einstein's theory.
00:52:44.000You can write down that geometry, and there it is.
00:52:47.000So the first question is, can you make it?
00:52:49.000And as we said, we don't think that stuff exists.
00:52:53.000There's a second set of theoretical bits of theoretical work, which if you had a wormhole, then what would happen if you tried to travel through it?
00:53:03.000And what seems to happen is that they become unstable the moment anything tries to go through.
00:53:10.000So you get kind of a feedback of stuff going through and through and through and through.
00:53:19.000He got the Nobel Prize last year for the gravitational waves.
00:53:22.000And he wrote a brilliant book, I think it's in the 80s, called Black Holes and Time Warps, where he talks about The answer is we don't fully know.
00:53:31.000But most physicists think that even if they existed, they will be unstable.
00:53:36.000And as soon as you even try to transmit information through them, send a bit of light through, then there will be this sort of feedback and they'd collapse.
00:53:43.000And ultimately, the reason we don't really know Absolutely.
00:53:47.000It's because you need what's called a quantum theory of gravity.
00:54:13.000So the conjecture basically was that the laws of nature will be such that you can't have stable wormholes and you can't build time machines.
00:54:21.000And if you sense something through it, it would destabilize it.
00:54:35.000That's called the tidal gravitational force.
00:54:37.000It's the difference in gravitational pull across your body, which is one of the things that gets you if you fall into a black hole.
00:54:44.000To the singularity, you can get, it's called spaghettified as a technical word.
00:54:50.000And it's just like the moon's, you know, the tidal effects on the Earth, which are quite small, but they still raise tides on the oceans.
00:54:57.000So that can be, if you think about something like a black hole, that can be a massive difference in gravitational pull from your head to your feet.
00:55:56.000Even in the solar system, I would not be surprised if we find microbes on Mars or on some of the moons of Jupiter or Saturn where there's liquid water.
00:56:19.000And almost as soon as it cooled down, we see evidence of life.
00:56:24.000So certainly 3.8 billion years ago, possibly even further back than that, we see evidence of life on Earth.
00:56:31.000So somewhere along the line, geochemistry, active geochemistry became biochemistry on Earth.
00:56:39.000And we have some idea, you know, that if you get gradients of temperature and acid and alkaline and the conditions that are naturally present on the surface of oceans, then complex carbon chemistry spontaneously happens.
00:56:56.000So we know that life, almost certainly we know that life began on Earth.
00:57:01.000I mean, the other option is it came from space or something like that, but it probably didn't.
00:58:04.000So it would be good to know if what I've said is right.
00:58:07.000And the way we find out is to find life or evidence of past life.
00:58:12.000Are you aware of the speculation that was going around?
00:58:16.000How recent was it, that Occupy thing, the octopus eggs?
00:58:22.000There was a group of scientists that were speculating that it's, you know, panspermia, the idea of panspermia, that it's possible that octopi had come from somewhere else, some frozen eggs had actually come from somewhere else and landed on Earth.
00:58:37.000And these are like legitimate scientists that are contemplating it, not morons.
00:59:37.000It has to do with the Cambrian explosion.
00:59:39.000And there were 33 authors on a paper that got published in The Progress in Biophysics and Molecular Biology that talked about this possibility.
00:59:49.000There are other people that disagree with it, though.
01:00:38.000I mean, they have incredible camouflage abilities that really don't exist in the mammalian world.
01:00:43.000Yeah, but on cellular level, you look at an octopus cell under a microscope and you wouldn't be able to tell the difference between an octopus cell and a human cell.
01:00:51.000So the only way that that would make sense is if all life comes from basically the same kind of building blocks and just varies depending upon the conditions and where it takes place.
01:01:00.000I'm guessing, but yes, that must be the only way you could sustain that, given that they're so similar to us, because they really are, biochemically, is that that's the only way it can be done, given the building block, the toolkit,
01:01:16.000the laws of nature and the elements and so on that we have in our universe.
01:01:19.000We have so many different life forms on our planet, but if we found anything that's remotely similar to what we have here on Earth on another planet, it would be such an incredible discovery.
01:01:29.000Like, if we found a frog on the moon, I mean, the world would stop, right?
01:01:34.000I'd be very surprised if we found a frog on the moon.
01:01:36.000But, I mean, if we found anything anywhere that is in any way similar, an insect on Mars.
01:01:43.000I mean, as I say, it'd be micro, I think it'd be single-celled things.
01:01:46.000Remember, I mean, you mentioned the Cambrian explosion.
01:01:49.000So that is, what we do know about Earth is that although life began, let's say, 3.8 billion years ago, it wasn't until around 600 million years ago or so, or maybe at most 700, that you see any complex multicellular organisms at all.
01:02:05.000So for something like 3 billion years, it was single-celled, alone.
01:02:10.000And that's one of the reasons why I would guess, if I had to guess, I would say that microbes would be common because life began very quickly on Earth.
01:02:18.000And I wouldn't be surprised if we find it on Mars.
01:02:20.000But complex life, multicellular life, insects, plants, intelligence, I would guess would be very rare because it took so long on Earth to get there.
01:03:14.000Two billion years ago, whatever it was, in some ocean...
01:03:17.000The bacteria cell got inside the Archean and survived as a symbiotic organism, essentially, and then somehow, unbelievably, managed to reproduce and replicate in that configuration.
01:03:34.000And that does seem to be the origin of all complex multisolar life on Earth.
01:03:38.000So it's called the fateful encounter hypothesis.
01:03:41.000And if that's true, then it's just a bit of luck.
01:05:10.000You know, there's a theory called the grand tack theory.
01:05:16.000It's very hard to explain the evolution of our solar system.
01:05:19.000So when you do computer models of solar systems, you don't tend to get four rocky planets too close to the sun and four big gas giants further out.
01:05:28.000And one of the current best theories, and I say this because it shows you how lucky we might be, Is that Jupiter, they tend to form these big gas giants and migrate inwards towards the star.
01:05:39.000So in almost all the computer simulations, just because you've got this big gas giant orbiting all the dust around the star, they tend to drop inwards.
01:05:49.000So it looks like it formed and came in, and came in almost to where Mars orbits today, and cleared out the region around Mars, actually, which is maybe the reason Mars is so small compared to Venus and Earth.
01:06:02.000But then Saturn was coming in as well.
01:06:06.000And in the computer models, the interaction between Jupiter and Saturn stopped Jupiter coming in before it gets to the Earth.
01:06:14.000And they both get dragged out again to where they are today.
01:06:56.000Bode's Law is a method of detecting, if you look at the mass of a planet, you can accurately detect how much mass and the size of a neighboring planet.
01:07:06.000I think it wasn't just the positions of the orbits, I think.
01:07:49.000Other than to say that most simulations of the solar system, if you put other planets in, they tend to get thrown out by gravitational interactions.
01:08:00.000So there is a sense in which our solar system has got as much stuff in it as it could have.
01:08:06.000And you're right, given the mass of them, that depends on how close another planet can be before the interaction goes wrong and it gets thrown out into the intergalactic space or something.
01:08:39.000They evolve and planets can shift orbits and change.
01:08:43.000And we know, if you look at the surface of the Moon, for example, it's covered in craters.
01:08:48.000And that was caused, they all seem to hit about the same time.
01:08:51.000And it's about 3.8 billion years ago or so.
01:08:55.000And that's called the late heavy bombardment.
01:08:57.000So we know that if you look at cratering rates on Mars and on the Moon, it all seemed to happen in this, not all, but a big peak around that time.
01:09:06.000And that seems to be correlated with Neptune moving outwards in the solar system and into the Kuiper Belt basically or towards the Kuiper Belt and causing all sorts of havoc and everything comes into the inner solar system.
01:09:19.000So those things happen but it didn't happen when life was established on the Earth.
01:09:44.000Do you think that it's possible, do you ever entertain the idea that it's possible that we are the only intelligent life in the known universe?
01:09:53.000I tend to restrict myself to the galaxy.
01:09:57.000So I do think it's possible that at the moment there's one civilization in the Milky Way, and that's us.
01:10:04.000And I think that's important, actually.
01:10:07.000And it goes back to what I was saying at the start about the Astronomy and cosmology being part of the framework within which you have to think if you're looking for meaning or you're looking for how we should behave even politically, you know, that has a bearing to me.
01:10:24.000I mean, imagine that we're the only place where there is intelligence in this galaxy.
01:10:32.000Should we actually, notwithstanding the fact that we're tiny and fragile things and insignificant physically, should we consider ourselves extremely valuable in that respect?
01:13:00.000I mean, I think what it says is you have to take responsibility for all those things, those spiritual things that you think about and the emotional things you think about.
01:13:23.000Make the best of it, would be my view.
01:13:25.000It's so unbelievably compelling, though, to consider the idea that somewhere out there, there's another civilization that may be even more advanced than us.
01:13:35.000And this thought of it is just so attractive.
01:15:42.000North Sentinel Island, which is a really unusual place because they branched off from Africa 60,000 years ago and they've been living on this one small island the size of Manhattan.
01:15:50.000And as well as we know, there's only about 39 of them left, somewhere around there.
01:15:59.000We're supposed to leave them alone, and they're a rare tribe.
01:16:04.000When they find them in the Amazon, the uncontacted tribes, our initial instinct is back off, back off, leave them alone, leave them alone.
01:16:11.000Do you think that perhaps the universe, like if there is a civilization that's a million times more advanced than us, been around here for millions of years of life as opposed to a quarter million, Why would they let us know?
01:16:26.000Would they look at us dropping bombs on each other and polluting the ocean and sucking all the fish out and putting clouds into the skies of dirt and particles?
01:17:13.000So it's possible, I suppose, that there are space probes all over the place that are so small and are so efficient and use so little energy that we just don't see them.
01:17:25.000My other thought is that where we are headed, it seems to me that there's some sort of a strange symbiosis that's taking place.
01:17:33.000There's a strange connection that we have to electronics and ultimately to an artificial creation, artificial intelligence, whatever you want to call it, artificial life, something that's created by carbon-based beings, cellular beings that isn't cellular,
01:19:18.000We have these biological motivations to survive and You know, there's motivations to conquer and to innovate and to spread our genes and to move into new territories.
01:19:27.000But if you didn't have biology, if you existed completely from man-made materials or from materials found on Earth and that this new form of life is created out of that, you wouldn't have those unless you programmed them.
01:20:08.000Does it have to have a sufficient level of intelligence that it actually is conscious?
01:20:13.000And all these things that we talked about, this word meaning that we used earlier, that we all understand and can't define.
01:20:20.000Is that an emergent property that has to emerge if you've got something that's intelligent enough to replicate itself and live?
01:20:32.000I don't know the answer, but it's worth considering that this thing, emotion, meaning, love and fear and all those things, Are just the things that happen when you are intelligent?
01:21:12.000It's like literally from a device not connected by any wires or anything, it's coming to me.
01:21:18.000If there's a possibility to create some sort of global intelligence through electronics that's non-local, if one piece of it falls off, it just repairs itself or figures itself out.
01:21:32.000But it's the same consciousness existing on a global scale through some sort of an electronic network that instead of the idea that you and I have that Brian and Joe, you have your mind, I have my mind, and we exist As intelligent beings separate from each other,
01:21:49.000but instead of that, that all of it is connected and that all of it is something that we can't even conceive of because our brains are too crude, like trying to explain to Australiapithecus what a satellite is.
01:22:08.000I mean, if you think about our brains, they are ultimately, what are they?
01:22:11.000They're just a distributed network of cells connected by neurons.
01:22:15.000And I mean, they're very complicated, but they are a colony of things that are autonomous in a sense, and they're communicating with each other.
01:22:23.000So yeah, I don't see why you can't scale that up in principle.
01:22:27.000I mean, the caveat is always that we don't know about this.
01:23:05.000So it's made of electrons and protons and neutrons.
01:23:08.000And if I have a soul in there, something that we don't understand, but it's a different kind of energy or whatever it is that we don't have in physics at the moment, it interacts with matter because I'm moving my hand around.
01:23:23.000It's something that interacts very strongly with matter.
01:23:27.000But if you look at the history of particle physics in particular, which is the study of matter, we spent decades making high precision measurements of how matter behaves and interacts.
01:23:38.000And we look, for example, for a fifth force of nature.
01:23:42.000So we know four forces, the gravity, the two nuclear forces, called the weak and strong nuclear forces, and electromagnetism.
01:24:22.000And you would have to jump through a lot of hoops to come up with a theory of some stuff that we wouldn't have seen when we've observed how matter interacts that is present in our bodies.
01:24:33.000And presumably if you believe in the soul, you want it to exist outside.
01:24:36.000When you die, you still want the thing to be there.
01:24:38.000And you might believe in ghosts and things like that.
01:25:54.000So this energy that's interacting with matter, even if you're not moving at all, if you're just thinking, it's interacting with the matter that encompasses your mind or your brain.
01:26:25.000But even if you're not moving, you're saying your body's interacting with matter as you're moving your arm, but even if you're not moving, if you're just thinking and you're completely still, which is not totally possible because your heart's beating and you're breathing and all that stuff, but if somehow or another you were able to isolate just the thought,
01:26:42.000the thoughts themselves are still interacting with matter because they're interacting with the brain itself.
01:26:59.000The woo-woo version is that the brain itself and the body, the physical, the spiritual self, you are merely an antenna that's tuning into the great consciousness of the universe.
01:28:38.000I think it goes to the heart of this question of what it means to be human.
01:28:44.000So I would say that being human, the answer, right?
01:28:51.000I don't have the answer to the meaning at all.
01:28:54.000But an answer would be, We are small, finite beings, which are just clusters of atoms.
01:29:04.000As we said before, they're very rare, but we understand roughly how they came to be.
01:29:10.000And we have a limited amount of time, not actually unfortunately, but because of the laws of nature.
01:29:17.000The laws of nature forbid us to be immortal.
01:29:22.000Immortality is ruled out by the laws of physics.
01:29:26.000But also, actually what's interesting about if you look at the basic physics of the universe, going from the Big Bang to where we are today, then the physics is driven by the fact that the universe began in an extremely ordered state.
01:29:41.000So it was a very highly ordered system.
01:29:44.000And it is tending towards a more disordered system at the moment.
01:29:48.000And that's called the second law of thermodynamics.
01:29:50.000And it's that basic common sense thing that things go to shit.
01:29:55.000Basically, it's the second law of thermodynamics.
01:29:57.000What we strongly suspect, and I would say no, is that In that process of going from order to disorder, complexity emerges naturally for a brief period of time.
01:30:13.000So it's a natural part of the evolution of the universe that you get a period in time when there's complexity in the universe.
01:30:20.000So stars and planets and galaxies and life and civilizations.
01:30:24.000But they exist because the universe is decaying, not in spite of the fact the universe is decaying.
01:30:32.000So our existence in that sort of picture is necessarily finite and necessarily time-limited.
01:30:39.000And it is a remarkable thing that that complexity has got so far that there are things in the universe that can think and feel and explore it.
01:30:51.000If you want an answer to the meaning of it all, it's that.
01:30:53.000That you are part of the universe because of the way the laws of nature work.
01:30:58.000You are allowed to exist, but you're allowed to exist for a temporary or for a small amount of time in a possibly infinite universe.
01:31:07.000One of the biggest mind-blowing moments, I think, of my limited comprehension of what it means to be a living being was when I found out that carbon and all the stuff that makes us has to come out of a dying star.
01:31:38.000That one alone, that there is some strange loop of biological life that comes from Stars, which is like the most elemental thing that we can observe.
01:34:10.000And I think that's what I think you miss out.
01:34:13.000I think if you decide to simplify it because you don't want to face that, you don't want to face the infinity that's out there in front of us.
01:34:21.000And you don't want to face those stories, as you said, that you look at your finger and its ingredients cooked in multiple stars over billions of years.
01:34:36.000And I think you're missing out if you don't want to face that.
01:34:39.000Well, I think the distribution of information has changed so radically over the last couple hundred years and particularly over the last 20 that you're seeing these trends now where more people are inclined to To abandon a lot of the,
01:34:54.000even if you remain religious or remain, you keep a thought or a belief in a higher power, people are more inclined to entertain these concepts of science and to take in the understanding of what has been observed and documented and written about among scholars and academics and There's more people accepting that.
01:35:20.000If you look at the number of agnostic people now as opposed to 20, 30 years ago, it's rising.
01:35:26.000And I think there's also, because of you and because of Neil deGrasse Tyson and Sean Carroll and all these other people that are public intellectuals that are discussing this kind of stuff, people like myself have a far greater understanding of this than I think people did 30, 40 years ago.
01:35:42.000And that trend is continuing, I think, in a very good direction.
01:35:47.000I mean, you know, what we should say is that science, we don't know all the answers, so we don't know where the laws of nature came from.
01:35:57.000We don't know why the universe began in the way that it did, if indeed it had a beginning.
01:36:04.000So we don't know why the Big Bang was very, very highly ordered, which is ultimately, as Sean Carroll actually, you mentioned him, often points out, and he's right, The whole difference, the only difference between the past and the future, the so-called arrow of time, is that in the past the universe was really ordered and it's getting more disordered.
01:36:24.000And that necessary state of order at the start of the universe, which is really the reason that we exist, that's the reason, because the universe began in a particular form.
01:36:49.000Science can sometimes sound arrogant, right?
01:36:51.000It can sometimes sound like it's the discipline of saying to people, well, you're not right.
01:36:56.000And it's not the discipline of saying you're not right.
01:36:59.000It's saying this is what we found out.
01:37:02.000So I like to say that it provides a framework within which If you want to philosophize or you want to do theology or you want to ask these deep questions about why we're here, you have to operate within that framework because it's just an observational framework.
01:37:18.000So everything we've said is stuff we've discovered.
01:39:05.000You see it all across the world in all different cultures.
01:39:08.000But I think that in the 21st century, religion needs to operate within that framework, if it's going to operate.
01:39:17.000There are still great mysteries, and it is appropriate to think about what it means to be human, and I've given you my view of what it means.
01:39:24.000But I don't think the problem comes when your theology or your philosophy forces you to deny some facts, some measurement.
01:40:41.000And I think that a guy like Dawkins just gets frustrated from all these years of debates with people who are uneducated or saying ridiculous things.
01:41:10.000Having said that, you know, I've kind of softened a bit over the years, actually, because Now, I think at this point, both in the US actually and in Britain and in some other countries, we are at a point, you've sort of alluded to it, where everybody's angry.
01:42:38.000So I think seeking consensus and diffusing anger, as you said, it is incumbent on all of us, especially people like us who have a public voice.
01:42:47.000We need to diffuse some of this anger because otherwise it will consume everyone.
01:42:52.000Yes, I've tried very hard to evolve in that respect and just get better at communicating ideas and get better at understanding how people receive those ideas.
01:43:01.000And I think it's easy to get lazy and to insult and sometimes it's fun.
01:43:21.000But I think in terms of discussing ideas, especially that are so personal to people, like religion, I've re-examined the way I interpret these ideas and the way I talk about these things.
01:44:38.000He talked about how thinking like a scientist, which means thinking in the way that nature forces you to think, can be valuable in other areas.
01:45:15.000It behaves like a little billiard ball thing, a pool ball that bounces around.
01:45:19.000But sometimes it behaves like an extended thing, like a wavy thing.
01:45:23.000And nature forces you to hold both ideas in your head at the same time in order to get a complete picture of the object, a description of an electron.
01:45:32.000And he said that's the valuable thing about quantum mechanics.
01:45:36.000Unless you're doing electronics or inventing lasers, you don't need to know this stuff.
01:45:40.000But if you want to learn how to think...
01:45:43.000It's valuable to be forced to hold different ideas in your head at the same time.
01:45:47.000It's really teaching you not to be an absolutist.
01:46:10.000Oh, you could be a libertarian, right, on the far conservative end, where you think that the individual is the only thing that matters, and that's it.
01:46:17.000But actually, of course, to have a function in society, you need a mixture of the two.
01:46:21.000And we can weight it one way or the other, but you need to hold both ideas in your head at the same time.
01:46:27.000And he said that's one of the most valuable things about science, because it forces you into modes of thought that are valuable.
01:46:34.000And that's what we're talking about here.
01:46:36.000Absolute positions are always just a blinkered subset of what's actually happening.
01:46:44.000You can't understand the world by being an extremist.
01:46:48.000You've got to hold all these views in your head.
01:46:52.000Well, I find that so often on this podcast because I talk with people I agree with and disagree with, and I always try to put myself in the head of the person that I disagree with.
01:47:03.000I always try to figure out how they're coming to those conclusions or where they're coming from.
01:47:09.000And I think it's so important to not be married to ideas.
01:47:14.000I got a conversation with someone about this.
01:47:17.000And they said, like, sometimes you change your opinions a lot.
01:48:25.000But in that essay, he said that the most valuable thing about science is the realization that we don't know.
01:48:34.000And he said, in that statement, he calls science a satisfactory philosophy of ignorance, by the way.
01:48:41.000He said, in that statement is the open door, the open channel, he called it.
01:48:46.000So if we want to make progress, we have to understand that we don't know everything and we have to leave things to future generations and we can be uncertain and we can change our minds.
01:48:57.000And he said that it's a great last line.
01:49:00.000I can't remember exactly what he says, but he said it's something like, it's our duty as scientists to communicate the value of uncertainty and the value of freedom of thought to all future generations.
01:51:08.000And that's one of the problems with religion is to say that you know when you do not or to say that you have absolute truth and absolute knowledge of something when it can't really exist.
01:51:18.000Yeah, I mean, history tells us, doesn't it, that anyone who thinks they've got absolute knowledge causes trouble.
01:51:55.000He talks about it like we're in the opening scene of a science fiction movie where he's trying to warn people and then they don't listen to the genius and it goes south.
01:52:08.000I chaired a debate on this with the Royal Society in London a few weeks ago.
01:52:14.000So it's true now, at the moment, what people tend to be frightened of are general AIs, or AGI they call it, artificial general intelligence, which is like what we talked about earlier, a human-like capability thing.
01:52:29.000We don't know how to do it, we haven't got them, and we're miles away.
01:52:33.000So at the moment, artificial intelligence is expert systems and very focused systems that do particular things.
01:52:40.000You can be scared of them in a limited economic sense because they're going to displace people's jobs.
01:52:46.000And actually, interestingly, in this panel discussion we had, it's going to be what you might call middle-class jobs in the UK, so white-collar jobs.
01:52:54.000Which is why people are interested in universal basic income to sort of replace money that's going to be lost because there will be no jobs for all these people.
01:53:01.000Otherwise, we have just a mass catastrophe.
01:54:23.000I mean, it's our choice at the moment, isn't it?
01:54:25.000I mean, don't give your iPhone a laser, you know, for example.
01:54:29.000And it doesn't matter if it goes crazy and tries to take over the world.
01:54:32.000I know that's a bit facetious because they can...
01:54:35.000He would say they could take over power grids and all that kind of stuff, I guess, but...
01:54:39.000Well, it's these concepts that are really hard to visualize, like Sura Kurzweil's idea of the exponential increase of technology leading us to a point in the near future where you're going to be able to download your consciousness into a computer.
01:54:53.000You talk to computer experts, they're like, there's no way we're miles away from that.
01:55:03.000But Kurzweil's convinced that what's going to happen is that as technology increases, it increases in this wildly exponential way where we really can't visualize it.
01:55:13.000We can't even imagine how much advancement will take place over 50 years.
01:55:19.000But in those 50 years, something's going to happen that radically changes our idea of what's possible.
01:55:24.000And I think Elon shares this idea as well, that it's going to sneak up on us so quickly that when it does go live, it'll be too late.
01:56:41.000Critical parts of being a person is that we need things to do that we find meaning in.
01:56:46.000Like you were talking about, we're the only things that we know of that have meaning, that find meaning and share meaning and believe in that.
01:56:55.000We're going to need something like that.
01:56:57.000If universal basic income comes along, I don't think it's going to be enough to just feed people and house them.
01:57:02.000They're going to want something to do.
01:57:04.000If you're doing something for an occupation and this is your identity, and then all of a sudden that occupation becomes irrelevant because the computer does it faster, cheaper, quicker, these people are going to have this incredible feeling of despair and just not being valuable.
01:57:29.000Which is make a living sort of thinking and creating and all that kind of, you know, so that's the utopian ideal is you don't need to do the stuff, the job that you don't really want to do in the factory.
01:57:52.000Well, it would be great if everybody had an interest like that, if everybody went on to make pottery and painting and doing all these different things that they've always really wanted to do, and their needs are met by the universal basic income money that they receive every month.
01:58:08.000But boy, there's a lot of people I don't think have those desires or needs and to sort of force it onto them at age 55 or whatever it's going to be seems to be very, very difficult.
01:58:25.000But I think that, in concept at least, it's inevitable that we do have some sort of an artificial intelligence that resembles us, or that resembles something like Ex Machina, if people choose to create that.
01:58:39.000I mean, choose to create it in our own image.
02:00:12.000They're driving down the road, streaming two people talking, where it's ones and zeros that are broken down into some audible form and you can listen to it in your car.
02:00:48.000So it's certainly in the early 90s I was involved in that.
02:00:52.000You know, in the university environment with email and all that kind of stuff.
02:00:56.000So I don't know when it kind of didn't really...
02:00:59.000You could have a web browser that just...
02:01:02.000The only sites that were there were NASA. And I think NASA had one of the early sites and CERN. And there's very little else.
02:01:09.000When did you become involved with CERN? So that would be, I started doing particle physics in 95. And when was, when did the Large Hadron Collider go live?
02:01:20.000That was, I remember it was 2000 and 2007, I think it was, or 2008. It's so long ago.
02:02:30.000So going back to what you said about the carbon and the oxygen, we can trace that story back way beyond the time when there were protons and neutrons to when there were quarks and gluons around and go all the way back and the Higgs boson doing its thing back then.
02:02:46.000So we can see all that physics in the lab.
02:02:50.000So that's why we have a lot of confidence in that story.
02:02:54.000It's so fascinating that they were able to talk someone into funding that.
02:02:58.000That they got a bunch of people together and that you were able to explain to politicians and, you know...
02:03:22.000And it was built out from the Second World War.
02:03:26.000So you have Europe at the end of the war.
02:03:28.000And it was realized that the only way forward for Europe was collaboration.
02:03:32.000To rebuild the scientific base and for peace, for peaceful purposes.
02:03:38.000And so CERN was set up as an international collaboration in Europe initially with that political ideal that it would explore nature just for freely and for peace, for peaceful means,
02:03:55.000And so that was, the politics was right.
02:03:58.000So it was set up by international treaty So that the member states are bound together by a treaty.
02:04:05.000And they pay a small amount, relatively small amount each, into CERN every year, which is a percentage of their GDP. And that's the money they use to do the experiments and build the accelerators.
02:04:41.000I mean, the reason that the US collider, the SSC, failed is It's because it's the problem you have in the US with the funding system, as you've seen in the last few weeks, is that it's very arbitrary and it's open to political manoeuvring and things can be shut down.
02:06:03.000You can do these wonderful things for not a lot of money if you just do it over many years and have stable funding and just commit to doing it.
02:06:45.000Well, we invented the World Wide Web, as we've just said.
02:06:48.000A lot of the medical imaging technology that we use comes from CERN. It's pioneered the use of these very high-field magnets, which is what it needed.
02:07:24.000So most particle accelerators today are in hospitals and in medicine.
02:07:29.000But they came from doing particle physics.
02:07:33.000So the spin-offs of these big experiments at the edge of our capability are always immense, which is why they're worth funding at these very low levels.
02:08:46.000So we've been exploring that because we don't only collide protons together, we can collide lead nuclei together or silver nuclei together at the LHC. And that's when you make these kind of soups of nuclear matter, if you like, very hot nuclear matter to explore that physics,
02:10:18.000I mean, one thing we're trying to do is, one of the things in particle physics is that you want as many collisions per second as you can generate.
02:10:26.000And we have a collision, we have what's called a bunch crossing at LHC. We can vary it, but it's something like 25 nanoseconds, depending on what, so it's really, we get a lot of collisions per second.
02:10:39.000And the more collisions per second you can get, the more chance you have of making interesting things like Higgs particles or whatever else may be out there waiting to be discovered.
02:10:49.000I mean, it's possible there are other particles out there that we haven't yet discovered that could be within the reach of the LHC. And if this one that was in Texas had gotten built and it was more powerful than the LHC, you'd have even more opportunity to do something like that.
02:11:13.000So the general rule in physics, in particle physics, is that the more massive it is and the more things it can decay into, the faster it will do that.
02:11:22.000So basically the heavy things decay into light things.
02:11:26.000And so the stable particles are things like electrons and some of the quarks.
02:11:33.000The up-quarks and down-quarks are stable things.
02:11:37.000So everything tends to decay very fast.
02:11:39.000So we're talking fractions, billions of a second, fractions of...
02:12:02.000So most of it's a load of particles that are spraying out which you're not interested in.
02:12:07.000But sometimes when, let's say, a couple of the gluons bang together, and they can make something interesting, like a top quark or a Higgs particle, What's a top quark?
02:12:40.000And then the charm and stranger, another family in the top and bottom are the third family.
02:12:44.000And so we, for some reason, so the only thing, the only particles we need to make up, you and me, are up quarks, down quarks and electrons.
02:12:52.000But for some reason, there are two further copies of those, which are identical in every way except they're heavier.
02:12:58.000So there's the charm and the strange quark and a heavy electron called a muon.
02:13:03.000And then there's the top and the bottom quark and another heavy electron called a tau.
02:13:09.000So there's this weird pattern that we don't understand.
02:13:13.000So it seems like you only needed the first family to build a universe.
02:13:18.000But for some reason, there are two copies.
02:13:22.000And the heavy ones decay into the lighter ones is the point.
02:13:25.000So when you make them, they're not around very long.
02:13:27.000And just to answer your question, what happens?
02:13:29.000Is that when they decay, they throw their decay products out into our detector.
02:13:34.000So we take a photograph of the cascade of particles that comes from these heavier particles decaying, and the trick is to patch it all up to try and work out what everything came from.
02:14:25.000We wouldn't exist if there wasn't mass in the universe.
02:14:28.000And the Higgs is ultimately responsible for that mass.
02:14:32.000I keep caveating it because then you get other sorts of mass that are generated, but the fundamental basic seed, as it were, is from the Higgs.
02:14:44.000So what we want to know is we want to know how that thing behaves.
02:15:28.000So we look out into the universe and we see that there's a lot of stuff there that's interacting gravitationally, but is not interacting strongly with the matter out of which we are made and the stars are made.
02:15:40.000So it's almost certain that that's some form of particle.
02:15:47.000And we see lots of different observations, the way galaxies rotate and interact.
02:15:51.000And even that oldest light in the universe, the so-called cosmic microwave background radiation, we see the signature of that stuff in that light as well.
02:15:59.000So we think that there's some other particle out there.
02:16:01.000And to be honest, we thought we would have detected it, I think, at LHC. We have lots of theories called supersymmetric theories that make predictions for all sorts of different particles that would interact weakly with normal matter.
02:16:16.000And I think it's broadly seen as a surprise that we haven't seen them at LHC. So that just may well mean that either they're a bit too massive, so we need more energy to make them, and we just haven't quite got enough.
02:16:31.000Or we're not making enough of them often enough to see them, which is one of the reasons we're upgrading the LHC. So we also look for them, by the way, directly.
02:16:41.000So we have experiments under mountains.
02:16:43.000We bury them under mountains so the cosmic rays from space don't interfere with them.
02:16:48.000And we're looking for the rare occasions when these dark matter particles bump into the particles of matter in the detector.
02:16:56.000Because the idea would be this room is full of them.
02:16:58.000I mean, the galaxy is swimming with dark matter, as far as we can tell.
02:17:02.000But it interacts very weakly with this matter.
02:17:06.000So it doesn't bump into us very often.
02:17:08.000So we're looking for the direct detection of it.
02:17:11.000And we're looking to make those particles at LHC. So it's everywhere, but it doesn't interact with us.
02:18:32.000So again, we talked about Einstein's theory earlier.
02:18:36.000So Einstein's theory, which works spectacularly well, says that if you put stuff into the universe, as we said before, then it warps and deforms and stretches.
02:18:46.000And it very precisely tells you, given the stuff that you put in it, how much does it stretch?
02:18:54.000And the measurement we have is how it's stretching.
02:18:57.000So the thing we observe is how the universe is expanding and how that expansion rate is changing and how it's changed over time.
02:19:07.000So we have very precise measurements of that.
02:19:09.000So then we can use the theory to tell us what's in it, given that we know how it's responding to that stuff.
02:19:16.000And that's how we discovered dark energy.
02:19:18.000So we noticed that the universe's expansion rate is increasing.
02:19:22.000So the universe is accelerating in its expansion, which is exactly the opposite of what we thought.
02:19:28.000And this is in the 1990s that we discovered that.
02:19:31.000So we can work out what sort of stuff and how much of that stuff you need to put in the universe to make that happen.
02:19:38.000And that's where we get these numbers from.
02:19:41.000Was there a resistance to that when that was first proposed?
02:19:44.000Yeah, I remember one of my friends, Brian Schmidt, got the Nobel Prize for that.
02:19:48.000And I remember I talked to him and he said, he was a postdoc, I think, at the time, so a young researcher.
02:19:55.000And he was making measurements of supernova, the light from supernova explosions, which are so bright that you can see them, you know, hundreds of millions of light years away.
02:20:04.000And he noticed that if you look at the data, the light is stretched in the wrong way.
02:20:09.000So we look at the stretch of light as it travels across the universe and the universe is expanding.
02:20:14.000It stretches the light, so it changes the colour.
02:20:17.000And he noticed that there was a discrepancy which said that the expansion rate is speeding up.
02:20:24.000It's been speeding up for I think something like seven billion years or so.
02:21:06.000And so a good scientist will be really happy if they turn out to be wrong because they've learned something.
02:21:13.000It's good that he took that path because he got the Nobel Prize.
02:21:16.000Now, when he received the Nobel Prize and this concept started being discussed, what was the initial reaction to it?
02:21:23.000Well, it's interesting because it's allowed in Einstein's theory, and it was in Einstein's original theory.
02:21:30.000So it's got a name, it's called the cosmological constant.
02:21:33.000And it's just allowed in the equations.
02:21:37.000And Einstein actually introduced it Initially, because Einstein's equations strongly suggest that the universe is expanding or contracting and not just sat there.
02:21:50.000So even before we'd observed anything, Einstein had a theory that suggested that the universe is just not static and actually really strongly suggests that there's a beginning.
02:22:01.000So the theory itself, on its own, suggests that you can see that if the universe is stretching today, then it must have been smaller in the past, right?
02:22:09.000Everything must have been closer together, let's say that.
02:22:12.000So there's a man actually called Georges Lemaitre, who worked independently of Einstein, but at the same time in the early 1920s, before we even knew there were other galaxies beyond the Milky Way.
02:22:24.000And they noticed that the equation suggests the universe might be stretching.
02:22:29.000And so he wrote to Einstein and said, your theory suggests there was a day without a yesterday.
02:22:35.000Because he thought if everything's expanding now, then it must have been closer together in the past.
02:22:40.000And so there might be a time when it was all together.
02:22:50.000But I think that he was more predisposed to accept what the equations were telling him because a beginning...
02:22:58.000An origin for a priest is really a nice thing because it tells you it's a creation event.
02:23:03.000And Einstein tried to dodge it and put this allowed term into his equation, which is almost the stretchy term to say, well, if it's all kind of contracting or something, can I put something in to make it stretch a bit, to balance it all out so it can be eternal?
02:24:09.000But it's still dominating the universe now.
02:24:12.000And it will dominate even more in the future.
02:24:15.000So we think that we're in a universe that will continue to expand, essentially doubling in size on a fixed timescale, which is about 20 billion years.
02:24:25.000So within every 20 billion years into the future, forever, unless something happens, the universe will continue to expand and double in size.
02:24:35.000And that's the dark energy that's driving that.
02:25:09.000But it looks like a very simple thing that doesn't change over time and just stays there.
02:25:14.000So it requires theoretical advance as well.
02:25:20.000And so people are trying very hard to do that.
02:25:23.000It's so crazy when you go from Galileo to modern theoretical physics that they're still in the midst of this understanding of what all this stuff is.
02:25:56.000Right now, it's very theoretical, right?
02:25:59.000They're trying to wrap their minds around what this is and what the properties of it are.
02:26:04.000Do you envision a time where you can actually physically measure this and have a real clear understanding of what it is and what its properties are?
02:27:05.000There's something really profound we don't understand about the way that stuff, in particular the Higgs actually, interacts with space and time.
02:27:15.000So very naively, the Higgs should blow the universe apart, just very naively.
02:27:21.000It's loads of energy in a very small amount of space, huge amounts of energy in the Higgs field.
02:27:28.000But it doesn't do anything apart from give mass to things.
02:27:31.000It doesn't seem to, it doesn't directly affect space.
02:27:36.000But everything else that you put in space directly affects it.
02:27:40.000So, you know, there are kind of issues there that we don't, and it just says we don't get it, we don't.
02:28:12.000I mean, it's probably tens of thousands if you count all the people who work at CERN and the particle physicists and the theoretical physicists.
02:30:56.000You must have a huge crew carrying all this stuff around.
02:30:59.000Yeah, that's like 16 or 18 people, and it's like a rock and roll show.
02:31:02.000And at some of the venues we're doing it in North America, in Canada, they're a bit smaller venues, but we just fill it with screen as much as we can get.
02:31:10.000And then the graphics, a lot of the graphics I have were done by D-Neg, who did Ex Machina, actually, and Interstellar.
02:31:17.000And the reason, I mean, I say chose them, I rang them up and goes, please, please, will you do this?
02:31:24.000And they said, how much money have you got?
02:31:25.000And, you know, because it's way lower than Chris Nolan, and they did it.
02:31:30.000They just liked the idea of these messages and these ideas.
02:31:33.000So they used the software that they used for Interstellar to create images of black holes.
02:32:01.000It's a simulation of what Einstein's theory tells us a black hole will look like.
02:32:05.000And so I can use that to talk about what happens when you fall into a black hole.
02:32:09.000What would you see watching someone fall in?
02:32:12.000And you can explain all that using Einstein's theory.
02:32:15.000The idea that it's kind of a well-known idea, it's a bizarre idea that if I was to fall into a black hole and you were watching, you'd never see me fall in.
02:32:24.000You'd see time slow down, my time slow down as you watch me.
02:32:29.000So in the end I'd just slow down and slow down and slow down and then I'd get frozen on the event horizon and just fade away as an image, a reddening image on the event horizon.
02:32:39.000So time passes at different rates as you move close to the black hole and far away because space and time are distorted by the mass of the black hole.
02:32:49.000And so I talk about all that but I talk about all that with this incredible image It's so high resolution, by the way, that it was higher resolution than they used for Interstellar because my screen's so big.
02:33:02.000So we need a special machine to play it.
02:33:05.000You can buy the most expensive Mac Pro in the world.