Joe Rogan Experience #1233 - Brian Cox

Brian Cox 0:01 That's very cool.

Joe Rogan 0:04 Three, two, one. Yeah, a guy named, uh... Well, it's, it's online Twitter ha- or his, uh, Instagram handle is TGTstudios. And he makes these... I actually had one made for Elon. Elon Musk loved it too, so we made him one with... He made one with, like, this very beautiful red wood.

Brian Cox 0:23 Yeah.

Joe Rogan 0:23 And those are... What are those things made out of, Jamie? The... Some diodes or something?

Brian Cox 0:26 Nixie tubes is what it's called.

Joe Rogan 0:27 Nixie tubes. He has to-

Brian Cox 0:29 It's like valves, right? They're old...

Joe Rogan 0:30 Yes.

Brian Cox 0:30 ... valve technology.

Joe Rogan 0:31 Yeah, he has to get them from Russia.

Brian Cox 0:34 Yeah.

Joe Rogan 0:34 That's, uh... He has them delivered over from Russia, so they might have, like, listening devices implanted in them as well.

Brian Cox 0:40 Yeah. (laughs)

Joe Rogan 0:41 So, Brian, good to see you, man.

Brian Cox 0:43 Great to be back.

Joe Rogan 0:44 Yeah, great to have you back.

Brian Cox 0:45 Girl, these shoes.

Joe Rogan 0:45 So tell me about this tour that you're doing.

Brian Cox 0:47 It's a, it's a, a world tour.

Joe Rogan 0:49 Try to keep this sucker like a fist from my face.

Brian Cox 0:51 Oh, yeah.

Joe Rogan 0:51 There you go.

Brian Cox 0:52 How's that?

Joe Rogan 0:52 Yeah, perfect.

Brian Cox 0:53 Yeah. So world tour, starts next week in, um, the UK, and then we go everywhere from the South Island in New Zealand all the way to the Arctic Circle, to Svalbard, which is north, th- the furthest north that you can go on a (laughs) commercial aircraft.

Joe Rogan 1:07 Wow.

Brian Cox 1:07 In the middle, we're in the States for a month, in, uh, mainly May. And, uh, yeah, it's, it's about cosmology and about the questions that cosmology raises. So if you're interested in the science of how did the universe begin, even questions of what may have been there. Is the universe eternal? Is there such a thing as before the Big Bang? What is the future of the universe? How does complexity emerge spontaneously in a universe? I mean, we sort of take it for granted that we, we... There's a big bang, and it's all hot, and there's just this kind of hot glow of stuff. And out of that, spontaneously, in 13.8 billion years, you get something like the Earth with a civilization and life on it. So how does that... Do we know anything about that? I mean, we do. I'm asking the question rhetorically. (laughs)

Joe Rogan 1:57 Right.

Brian Cox 1:57 We know quite a lot about it. So it's, it's really about showing the size and scale of the universe, but addressing those questions I think everybody has about what does it, what does it mean to be human? This tiny little finite life that we lead in a possibly infinite universe, how do you make sense of that?

Joe Rogan 2:14 Well, it's incredibly exciting to me that th- there's a giant audience for this, and that wha- what Neil deGrasse Tyson had been doing and what a, 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... I mean, I 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.

Brian Cox 2:37 Yeah.

Joe Rogan 2:38 And it's, it's spreading information. It's spreading knowledge.

Brian Cox 2:41 Yeah. I mean, it's... In the UK particularly, I mean, D- Wembley Arena, for example, you know?

Joe Rogan 2:45 Wow!

Brian Cox 2:45 You're talking about 10,000 people, 12,000 people-

Joe Rogan 2:48 That's incredible.

Brian Cox 2:48 ... in these shows. And you're right, they are coming. Al- although, you know, they're, they're big shows, spectacular screens and all that. They're, they're coming for to think. Th- th- they're coming to hear about what we know about the universe and nature. And I think... You know, I think... I'm not surprised people are interested, because these are questions that everybody asks. You know? I mean, just why am I here? You know, everybody's sat-

Joe Rogan 3:09 Yes.

Brian Cox 3:09 ... there asking that question. But I... My point is that there is a framework, there's a framework of knowledge. There are things we know about the universe. So it is true that science, scientists are not gonna tell you why you're here. (laughs) They're not gonna tell you what the meaning of life is. But there is actually a, a... There are things you need to know if you want to start to explore those questions for yourself. I mean, you need to know that there are two trillion galaxies in the observable universe. You need to know that the Milky Way galaxy has got 200 billion stars. Most of those stars now we know have planetary systems. We estimate there are t- something like 20 billion Earth-like planets, or potentially Earth-like planets, in the Milky Way galaxy alone. So if you're asking questions about, "What is my place in the universe?" you need to know those things first of all. It's a framework within which you can think.

Joe Rogan 3:58 When you get to those numbers, when you're talking about trillions and billions and tho- all those zeros, my brain just goes numb. I... There's this lack of comprehension that I'm, I'm well aware of. Like, those numbers get thrown about, I go, "Oh, 200 billion."

Brian Cox 4:13 Hmm. No, every-

Joe Rogan 4:14 And it just (swoosh sound) .

Brian Cox 4:16 I think everybody does. I think ev- every scientist that... No scientist can picture that number. I mean, e- even the small number, 200 billion- (laughs)

Joe Rogan 4:25 The small number, right.

Brian Cox 4:25 ... the number of stars in one galaxy. And then when you say two trillion galaxies, y- you know, that, that's... I challenge anyone to be able to picture that. But it is the reality that we've observed. We've... You know, we... I mean, we haven't counted all two trillion, by the way. We have, we have a thing called the Sloan Digital Sky Survey, which maps the positions of galaxies. So you can... 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. And you get this picture of a vast and possibly infinite universe. I mean, we, we know that the universe, or very strongly suspect, that the universe is much bigger than the piece we can see. So we have good reason to think that's the case. Whether it's infinite or not is another question. And then that goes to your, you know, the, can you picture infinity?

Joe Rogan 5:16 (laughs)

Brian Cox 5:16 Well, no one can picture infinity.

Joe Rogan 5:17 No.

Brian Cox 5:17 There's a, there's (laughs) a weird thing as well about... You know, we, we say the universe began 13.8 billion years ago. So that's a measurement, so... Because we can measure the speed that all the galaxies are flying away from us, essentially. And then you, so you can run time backwards, if you like, to, to find out when they were all on top of each other. And so it's quite a simple measurement, and we've done that. So we say the universe began 13.8 billion years ago. But actually, all we know really was the universe was very hot and very dense at that time. And we have some theories that the universe was in existence before that, and perhaps some sort of circumstantial evidence. And that means that actually the universe could, could have always been there, eternal. And, um, when, when I talk to people sometimes, they get a bit... Some people get upset about that. Some people would rather it had a beginning. (laughs)

Joe Rogan 6:03 Yeah.

Brian Cox 6:04 And the, the idea that it might have been around forever...... is more frightening somehow than the fact that it began. And that it's, it's interesting the way that people's minds work. What, what terrifies you the most, an eternal universe or a finite universe?

Joe Rogan 6:18 Yeah, they're both incomprehensible. The, uh, the eternal universe, the w- 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 or?

Brian Cox 6:36 Yeah, it could do. So those theories are, are back in vogue. Some of those theories are back in vogue again. So yes, some of them say that there's a, a cycling universe. Um, so the Big Bang is an event when space gets very hot and very dense and filled with particles, and that may happen again. Uh, some of the other theories, uh, 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. 'Cause it's got some very special features, the Big Bang, which we could talk about. But inflation is the idea that space, space-time was around before the Big Bang and it was expanding extremely fast, and it was doubling in size, in the most popular of these theories, every 10 to the minus 37 seconds, which is .000000 with 37 noughts, one of a second. So it's an unimaginably fast expansion. And then the idea is that draws to a close, so it quite naturally sort of dies away and the expansion slows down, and 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. And those theories, the slight extension to those, um, say that, that, that slowing down just happens in little patches. So most of the universe, the overwhelming majority of the universe is still inflating at that insane s- speed, and that just little patches stop, and they're Big Bangs. So you get multiple universes, a multiverse, it's called the inflationary multiverse, and we are in one of those bubbles, and that's one of the more popular theories.

Joe Rogan 8:14 That's another one. I mean, that right now, I'm aware of what you're saying. I, I, I can, I can sort of visualize it in some sort of a graphic form, but it's incomprehensible. Like my-

Brian Cox 8:25 Yeah.

Joe Rogan 8:25 ... my mind doesn't, it doesn't have the capacity to expand the, this sense of distance and size to that, that grasp. Is this because of just the way we evolved, we evolved here on Earth to deal with the space that's in front of us, and now over the course of, you know, in industrial civilization and education, we are now grasping these concepts that are so alien to the v- reality, the, the tangible reality that we exist in every day?

Brian Cox 8:55 I'm sure that's right. Um, there, the, you know, even very simple things, like you go back to the Greeks, so Aristotle and those great, you know, very clever people, but they thought the Earth was at the center of the universe. Now, why? Because it feels like it's at the center of the universe.

Joe Rogan 9:09 Right.

Brian Cox 9:10 It feels like we're not moving, um, and that's quite a deep point actually in physics. It's like, why is it that we're flying around relative to the sun very fast at whatever speed it is, 18 miles a second or something like that, and the whole solar system's going round the Milky Way galaxy and so on, but why is it that we don't feel it? And, um, the Greeks, quite naturally, said, "Well, because we're at the center of the universe." They also said everything falls towards the Earth, so therefore the Earth must be at the center. It's, it's natural.

Joe Rogan 9:37 Right.

Brian Cox 9:38 And, and actually it's quite a deep, uh, thought to, to understand why it doesn't feel that we're moving. It, uh, you have to go all the way to Einstein really for someone to take that very seriously. And he, well, he said actually, he said, "Well, this..." Um, 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. So if we think about space, if I said, "Space," to you or most people I suppose, you'd think i- the way that Newton did of a big box within which things happen. And that's gotta be the, that's a natural picture of space and the universe, isn't it? It's a, a thing in which all the planets and galaxies are placed. But, um, in, in The Brief History of Time, Hawking says, "Well, imagine bouncing a ball." So we bounce a ball on the table now, a tennis ball. So I drop it and I catch it again. Um, so let's say I drop it and it takes a second to bounce up. So in that second, the Earth has moved about 18 miles or so in space around the sun. So you could ask the question, did that ball return to the same place in space or not? And the answer is, you can't answer it. You... It does from our perspective. But from the perspective of someone watching the Earth go all the way around the sun, it went up and caught it again, it had moved 18 miles.

Joe Rogan 10:55 (sighs)

Brian Cox 10:55 And then from some other perspective, it would've done something else. So the point is, you can't say this is a point in space, it came back to the same place, because that just depends on your perspective. It depends on whether you're watching the sun... The Earth go around the sun or whatever it is. So, so Einstein said that means there's no such thing as absolute space.

Joe Rogan 11:14 Oh.

Brian Cox 11:15 Which is, it kind of follows if you think about it, but that's a difficult... It's, it's a cool, but difficult thought process.

Joe Rogan 11:22 Right. I mean, that's, that's essentially what's happening when you're on a plane. I mean, if you're throwing a ball up in the air and catching it on the plane, it's happening at a much smaller scale, right?

Brian Cox 11:29 Yeah, yeah. I mean, you're flying at, whatever, 600 miles an hour relative to the ground.

Joe Rogan 11:33 Yeah. But it doesn't seem like it when you're sitting there.

Brian Cox 11:35 Yeah. And Einstein elevated that to a principle and said, "If you're moving at a bu- if you're not accelerating, you're just moving at a constant speed, uh, in a plane or now..." I mean, that's essentially what we're doing now, we're moving around the sun at effectively constant speed, "... then you can't tell." So there's no experiment you can do. We 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. Therefore, that concept has no meaning because you can't measure it.And that, there, or that's led Einstein to relativity.

Joe Rogan 12:13 Wow.

Brian Cox 12:13 So that, that's the, the basis of general relativity, which is our best theory of the universe.

Joe Rogan 12:19 Now, why is it that we think that the known universe is larger than what we can observe?

Brian Cox 12:27 Well, one point is that it's, um, expanding (laughs) and, and we, we always see the same radiation out there, so the glow of the Big Bang. But there are some deeper reasons. Um, the one, uh, from the theory of inflation, the, the, uh, the, the w- 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. So for example, we measure space to be what's called flat. I don't even have to tell you what's called flat, it is flat. (laughs) So if you imagine slices of space, let's imagine slices of them at different times. So, so you just slice the universe and, and say there's a big sheet. It's like this table.

Joe Rogan 13:11 Okay, like a table.

Brian Cox 13:12 There's a sheet of space, and there's another sheet, another sheet. And it can, it can have a geometry, right? It can be flat, like a tabletop, or it could be curved, uh, like a sphere, or it could be curved in the opposite direction, sort of like a saddle or a bowl. And we can measure that. And when we measure it, we see it's absolutely flat. And that's a very unusual thing for it to be like. Um, it requires... Because what, what Einstein's theory says is that the, the shape of space, that the curvature of space is determined by the stuff that's in it. That's, that's basically Einstein's theory of general relativity. Put stuff in space and it curves it and bends it and warps it and stretches it and so on. And what we find is that w- there's precisely the right amount of stuff in the universe to have a completely flat universe. And the, the, the explanation, the most favorite explanation for that is the universe is way bigger than the piece we can see. And so it's like looking at a piece of the Earth, how you look at little one-mile square of the Earth, right? Then it's, it, it's flat, right? (laughs) You have to look at big distances, kind of of order the radius of the Earth, or not, you know, bigger, bigger than one kilometer anyway, or one mile, to see that actually you're on a curved surface. And that's one of the ideas about the, the universe and why it appears to be the way that it is, because it's way, way bigger. So we just, we're just looking at a little piece, and that's why it looks flat, and that's, you know, one of the ideas.

Joe Rogan 14:37 Now, when you say flat, like that... My, my brain doesn't understand this because from our perspective, when you look up at the Milky Way, you see all these stars all over the place. So if you're saying flat, like what, how much height and what, what are you saying-

Brian Cox 14:53 Uh, so-

Joe Rogan 14:53 ... so in terms of like the way to measure it?

Brian Cox 14:55 The, the, the best way to think about it is not to think of three dimensions as face 'cause then we can't picture it.

Joe Rogan 15:00 Okay.

Brian Cox 15:00 But you can think of two, like this tabletop, and that's all right. We just forget the other one for now. And so you know what flat is on this table. I mean, you could define it. So you could say, for example, that if I draw a triangle on the top of the table, then all the angles add up to 180 degrees. So that actually defines flat. If you did that on the surface of the Earth with a big triangle, then the angles wouldn't add up to 180 degrees. Um, or you could draw a circle and say, "What's pi?" So pi is the ratio of the circumference of a circle to its diameter. That's only true on a flat surface. It's different if the surface is curved. So you can define flatness.

Joe Rogan 15:39 So when you're... but when you're saying flatness, how, what is the height and what is the width? Like if you're, you've been talking about it as if it's a table, there must be some sort of a... there's a dimension to it, correct?

Brian Cox 15:50 Oh, yeah. There's a third dimension of space.

Joe Rogan 15:51 Right.

Brian Cox 15:52 Uh, but the i- the same applies. It's just a generalization of geometry then. (laughs) So you, you can pi- the, the point is we can picture it in two dimensions. But you can, you can draw... Y- you can quite literally, you could imagine sending light beams out. And we do this measurement actually. We can look at the, the, the dist- the most distant light we can see, which is something called the cosmic microwave background radiation, which is... If you, if 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. It's the most distant object you can see with the naked eye, and it's about two, two million light years away or so, which means the light took two million years to get to us. So it's a long way away, but it's very big. So y- as you look further out into the universe to more and more distant galaxies, you're looking further back in time 'cause you look at something that's a billion light years away, then the light took a billion years to get to us. So you see it as it was a billion years in the past. And 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. So we can look to light that began its journey before there were galaxies, and that's the, the oldest light in the universe, which is, by the way, one of the, one of the pieces of evidence when people say, "I don't believe in the Big Bang." The answer is, "Well, you can see it." (laughs) "So, you know, it's just there." You can see it. We have pictures of it. Um, that light, it turns out that there are sort of structures or ripples in that light, um, which we can use as a ruler. So quite literally, as a, as a ruler on the sky. And then because that light's been traveling through the universe, we can see how that rule has been distorted as, as, as the light has traveled through space. And so we can infer whether space is flat or curved or how it warps, if you like, just from that measurement.

Joe Rogan 17:43 Is-

Brian Cox 17:43 It's a beautiful measurement.

Joe Rogan 17:45 Is it possible that in the future we'll be able to see past 13.8 billion years?

Brian Cox 17:49 Not with light.

Joe Rogan 17:50 Not with light.

Brian Cox 17:50 Because what... The, the picture is that before... It, it's actually was released 380,000 years after the Big Bang. It's a very precise number. You might say, "How do you know that?" Well, before that time, the universe was so hot that atoms couldn't form. So you had a soup of electrically charged particles. It was just too hot for electrons to go into orbit around nuclei. So the universe was opaque to light. So you just couldn't... It was like one... almost like a big glowing star, if you like.And then when it was expanding, it cooled past the point where the atoms could form. And at that point, it becomes transparent, really almost instantly in a cosmic time scale. And so the light could then travel in straight lines through the universe, and we can see that light. So we see the light from that time, but further back than that, it's opaque, so you can't see past that with light. But 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. And that se- looks for ripples in the fabric of space and time. And in principle, if we had a big enough detector, you could see the ripples from the Big Bang. So you could in- you could take an image of the Big Bang in gravitational waves, which would be ... But you need a enormous sort of space-based detector that we're not gonna build any time soon.

Joe Rogan 19:12 Now, obviously, this is all through equipment and technology that's been invented over the last few hundred years-

Brian Cox 19:18 Mm-hmm.

Joe Rogan 19:18 ... and perfected. Is it possible that things could get better, and you could get, uh, some, some ability to detect things, even in a, a far more distant way?

Brian Cox 19:28 Yeah, I mean, the, I think gravitational waves are, are incredible. I mean, Einstein predicted them in 1915. N- never thought they'd be detected-

Joe Rogan 19:36 Hmm.

Brian Cox 19:36 ... because you need such a hyper ... You need lasers, for ... Didn't have lasers.

Joe Rogan 19:40 Right.

Brian Cox 19:40 But the thing, LIGO, this experiment, which is half in, uh, near Seattle in Washington State and half in Louisiana, so they've got two detectors. And they're basically sort of, uh, I don't know, three-mile-long laser beams, um, that just sit and measure the sort of stretching and squashing of space as the ripples in the fabric of the universe go through. And, and what they've been observing, uh, collisions of black holes. So you can imagine-

Joe Rogan 20:06 Wow.

Brian Cox 20:06 ... how extreme ... Like, a colliding black holes is an incredibly extreme event, so it shakes the fabric of the universe, and the ripples come across the universe. And these laser beams, which are just basically rulers, can detect it. They just sort of ring almost, like, you know, just vibrate as the ripples go through, in space and time. Kip Thorne, who got the Nobel Prize, uh, last year for this, he's one of the greatest living physicists, hi- I once heard him describe it as a storm in time. So you've got this, a time storm. It's a beautiful image. (laughs) But-

Joe Rogan 20:40 Oh, God.

Brian Cox 20:40 So that technology's incredible, 'cause it, it, the change in length, is I can't remember the exact number, but it's way, way, way less than the diameter of an atomic nucleus, so the change in, in length of the beams. It's tiny measurement, but we can do it.

Joe Rogan 20:55 So this ti- a collision of black holes, the idea that you can detect that-

Brian Cox 21:00 Yeah.

Joe Rogan 21:00 ... that ...

Brian Cox 21:01 Yeah. They, the, the, there were ... I s- the paper, the first paper they published, there are two black holes, and they were about 30 times the mass of the sun each, and they were orbiting each other and spiraling in towards each other. And, uh, they accelerated. At one point, they were approaching each other at one-third the speed of light, and they accelerated to two-thirds the speed of light in a tenth of a second and then hit each other. And the explosion, the energy release, was ... I think I'm right, it was something like 50 times the energy release that the power of all the stars in the observable universe glowing, and it was something like 50 times that amount of energy for a tiny fraction of a second.

Joe Rogan 21:46 Whew.

Brian Cox 21:46 But it's, it's an unimaginably violent event, and that's why our detectors can see the ripples that that makes in space and time. And we detected, God, maybe it's two or three of them now, and, and also, uh, two neutron stars colliding, we saw that as well with it. So it's an incredible m- machine, which is why it got the Nobel Prize.

Joe Rogan 22:06 Now, there's a super massive black hole at the center of every galaxy.

Brian Cox 22:10 Yeah, yeah, we think.

Joe Rogan 22:10 But there's also other black holes that aren't necessarily in the center of galaxies?

Brian Cox 22:15 Yeah, so these little ones, well, little, you know (laughs) -

Joe Rogan 22:17 Little. (laughs)

Brian Cox 22:18 Um, they, they're, they're a few times the mass of the sun, and they're from collapsed stars. So they are stars at the end of their life, very, n- 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. And if they're sufficiently massive, then there's nothing that can stop the collapse, and so they collapse, as far as we know, to a point, right, uh, uh, essentially an infinitely dense point. We don't really know what happens at the ... W- we don't know what happens right in the middle. But they collapse to such an extent that there's a region around it where, from which light can't escape, and that's, uh ... So nothing can escape, and that, that's a black hole.

Joe Rogan 23:00 And what happens to them? Do they travel? Are they moving through space?

Brian Cox 23:06 Yeah, they, they're, they're, they're still stars.

Joe Rogan 23:08 Right.

Brian Cox 23:08 Uh, you know, so they're, they're still there. Um, they, they're surrounded, this region, where if you fall in, it's called the event horizon, and if you go across that horizon, then you are going to the center. There's one way of thinking about it, which is quite cool, which is that, uh, the time and space sort of flip, is one way to think about it. So in the same way that we are going into the future now, so, so we're going to tomorrow, there's nothing we can do about it, we are going to tomorrow, um, in the same way, if you fall in across the event horizon of a black hole, you are going to the middle, the singularity, it's called. So that's, that's your future. Every, every line of your future points to the center of the black hole, so it's kind of the ultimate (laughs) o- no escape, the ultimate prison. You're gonna get squashed to an infinitely dense point, basically.

Joe Rogan 23:57 So n- but not every star becomes a black hole at the end of its life?

Brian Cox 24:01 No, uh, 'cause if, if, um, something like the sun, um, then-

Joe Rogan 24:05 We have a small star.

Brian Cox 24:06 It's quite small, yeah. And, and when it collapses, there's a, there's a, uh, 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.So it's called a Pauli exclusion principle. But essentially what happens is that ... So as they get squashed closer and closer together, they move faster and faster to sort of get out of each other's way, if you like, and that makes a force which holds them up. And so that creates what's called a white dwarf star. So, so you can have a blob of matter. They're about the size of the Earth, but they're about the mass of the sun. And, uh, so that's, that's for smaller stars. They end up as these white dwarf things which are very dense objects. There's another version which is called a neutron star which is the same thing, but for neutrons. And they, they move faster and faster, so the ... If it's, if it's massive enough that it overwhelms the electron thing, then the electrons sort of fu- ... Crush into protons and turn into neutrons, and the whole things starts again. And so a neutron star can be, you know, at lea- ... One and a half times the mass of the sun, let's say, but it can be, uh, about, what, 10 miles across. (laughs) So-

Joe Rogan 25:18 Wow.

Brian Cox 25:18 So that's an incredibly dense ball of matter held up by this n- ... The neutrons moving around. It's got a fancy name, it's called neutron degeneracy pressure, but that's what it is. (laughs) But if you go even bigger then even that can't hold it up. And as far as we know then, there's no known force that we know of that can hold, hold the thing up if it's m- ... If it's too massive.

Joe Rogan 25:38 S-

Brian Cox 25:38 And so that's when it just w- ... Almost winks out of existence, if you like. I ... It collapses and collapses and collapses, um, and that's when you get a black hole.

Joe Rogan 25:46 We try to put that into perspective, the eart- ... The sun is a million times bigger than the Earth.

Brian Cox 25:50 Yeah.

Joe Rogan 25:50 And this, this neutron star is, wha- ... What'd you say, one and a half times the mass of the sun-

Brian Cox 25:56 Yes, but they, they-

Joe Rogan 25:56 ... but 10 miles wide?

Brian Cox 25:57 Yeah, yeah. So ... And there's loads of those around. They're, they're called pulsars.

Joe Rogan 26:02 (laughs)

Brian Cox 26:02 So we, we, we see those all over the place. The, the first one that was discovered was called LGM-1 because they spin very fast and, um, th- ... It was called LGM-1 'cause it's a very regular pulse and they thought it was little green men.

Joe Rogan 26:15 Oh, wow.

Brian Cox 26:15 So they called it, kind of jokingly, Little Green Men 1.

Joe Rogan 26:18 (laughs)

Brian Cox 26:18 And, um, so, yeah, there ... We, we've seen the ... There's one called the Crab Pulsar which is in the Crab Nebula which we saw the supernova explosion. So that's when a ... When one of these stars explodes at the end of its life and then collapses to form a neutron star. And we saw that in 1054 AD.

Joe Rogan 26:36 We- ... Wasn't there some speculation that our gal- ... Or our solar system at one point was ... Had a ... Was a binary star system and that one of those stars had become a dwarf?

Brian Cox 26:50 I don't know. Um, I haven't heard that.

Joe Rogan 26:52 Some- ... Someone ... I'd read something about that in relationship to the dense object they believe is outside the Kuiper Belt.

Brian Cox 26:59 Yeah, I mean, there's some evident- ... There's a bit of evidence that there's something out there, yeah.

Joe Rogan 27:02 Yeah.

Brian Cox 27:03 Um, cou- ... Because of the periodic extinctions and things on Earth, like, you get periodic bombardments from out in the Kuiper Belt, so yeah, I think one of the theories is that-

Joe Rogan 27:11 Periodic extinctions?

Brian Cox 27:13 Well, yeah, so if we're talking about like the ... You know, there, there've been ... There have been mass extinctions on Earth when, when a lot of the life died and, um, we don't know what caused all those, but, um, sometimes they're impacts from space. That seems clear. And so yeah, there are theories that there's something orbiting out there which can disrupt all these objects out in the Kuiper Belt that sends loads of comets and, you know, asteroids inwards to the inner solar system-

Joe Rogan 27:39 Ah.

Brian Cox 27:39 ... and it can cause, uh, havoc. And so the- ... There's some people look at those theories. I mean, I don't know. It's one of those i- it is a possibility that there's something out there.

Joe Rogan 27:49 Right because the speculation-

Brian Cox 27:51 So-

Joe Rogan 27:51 ... was that there's something out there's ... Correct me if I'm wrong, something called the galactic shelf, like, that it gets to a certain space and it indicates that there's something far larger out there.

Brian Cox 28:01 Uh, yeah. I mean, I think ... I don't know the exact- ... About the stellar-sized or mass objects-

Joe Rogan 28:08 Mm-hmm.

Brian Cox 28:09 ... out there. I don't know that. I mean, there are some, uh, sort of suggestions there's another planet out there, a big planet, for example. But you're, you're right, there can be, there can be stuff orbiting way beyond the Kuiper Belt. And we're talking, you know, a light year away or something like that now. Um-

Joe Rogan 28:24 It's, it's interesting because it's incomprehensible the distance, right, in, in our minds, how far that must be out past what we used to call Pluto, but for whatever reason, that becomes more interesting 'cause it's in our neighborhood-

Brian Cox 28:37 Yeah. (laughs)

Joe Rogan 28:37 ... whereas if they find some distant star system and ... That it might have a planet that's similar to Earth, that doesn't seem as, uh, compelling for whatever weird reason.

Brian Cox 28:48 No- ... Yeah, I mean, I, I think the, the planets around Alpha Centauri and Proxima Centauri which are the closest stars, it seems like there are planets around those now. And i- ... That, that was interesting because we could conceive of going there.

Joe Rogan 29:01 Right.

Brian Cox 29:01 And there was this idea ... Yeah, Stephen Hawking actually and some others, uh, before he died had this idea called Breakthrough Starshot which is the idea to send a little probe, uh, out to, uh, the center- ... The Alpha Centauri system and it, and it ... I think in their view, Y- Yuri Milner as well, the, the ... You know, the, the entrepreneur wanting to do that, and, uh, there ... It's ... I think it's, uh, something like 100 years travel time or something with, with the ... with our current technology. And they've pointed out that, you know, we don't do that now. We don't think 100 years in the future, but if you go back when people were building cathedrals people used to routinely start projects that would take 100 years to bear fruit.

Joe Rogan 29:40 Yeah.

Brian Cox 29:40 And so we could imagine going there and that's ... That then becomes fascinating, I think, 'cause then you've got a solar system, another solar system, that you could go and visit conceivably.

Joe Rogan 29:51 Conceivably. Yeah, I mean, what kind of speed are we talking and how long would it take to get there?

Brian Cox 29:57 Well, yeah, I mean, so it is ... I think the, the idea was about 100 years to get there.

Joe Rogan 30:02 Oh.

Brian Cox 30:02 So it's going, you know, four light years or so in 100 years, so whatever that in terms of-

Joe Rogan 30:06 So you would have to essentially do what they did in, like, the Ridley Scott Alien film and put people into some sort of a hyper sleep-

Brian Cox 30:12 Oh, yeah, a robot probably. It wou- ... It wouldn't be a crew. It prob-

Joe Rogan 30:15 It wouldn't be possible for w- ... A crew?

Brian Cox 30:18 Well, it is.

Joe Rogan 30:19 But you'd have to freeze 'em?

Brian Cox 30:20 Yeah. That's always... Th- You know, whenever you talk to engineers, you had Elon on, didn't you? It's like-

Joe Rogan 30:23 Yes.

Brian Cox 30:24 Engineers always say, "You know, if physicists go, 'Well, it's possible in principle,' so over to you."

Joe Rogan 30:28 (laughs)

Brian Cox 30:28 You know? (laughs) "You, you do it now. There, there are no laws of physics that tell us-

Joe Rogan 30:31 Right.

Brian Cox 30:31 ... we can't do it, so we just do it."

Joe Rogan 30:33 Right.

Brian Cox 30:33 But, you know, it's... (laughs)

Joe Rogan 30:34 That's a weird relationship-

Brian Cox 30:35 It's... (laughs)

Joe Rogan 30:35 ... between the physics, physicists and the engineers.

Brian Cox 30:37 Yeah. Yeah, yeah.

Joe Rogan 30:38 Yeah.

Brian Cox 30:39 But, but yeah. I- in principle, you're right. I- if you can send a little robot spaceship there, you can send a, a crewed spaceship there.

Joe Rogan 30:45 I'm, uh, uh, of the opinion as time goes on and augmented and virtual reality gets better and better that, uh, it doesn't really totally make sense, unless we're talking about colonizing some place, to send biological life to another planet. And if we can send some probe that doesn't have to worry about the, you know, the biology being affected by radiation or by the speed of travel or even-

Brian Cox 31:08 Mm-hmm.

Joe Rogan 31:09 ... by food, we can send something out there and almost be there by v- virtue of, you know, f- goggles, virtual reality goggles-

Brian Cox 31:18 Mm-hmm.

Joe Rogan 31:18 ... or, or something else.

Brian Cox 31:19 Yeah. Uh, you hear that in science, uh, at the moment, space science, we have this debate a lot actually because, of course, um, space probes like Curiosity that's on Mars at the moment, that's really cheap, uh, compared to sending people to Mars. And so quite often the scientists who want to find out about the worlds will say, "Well, we should spend it on robots. We shouldn't spend it on people." I think crewed space exploration is in s- 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.

Joe Rogan 31:52 For now.

Brian Cox 31:52 Yeah. But, but I think it has to be... It's about something else. I mean, it's about... It... And it's not only... It, it's about living and working off the planet, which I think is quite a persuasive argument actually. We've, we've already industrialized near Earth orbit, so it's already a multi-billion-

Joe Rogan 32:12 Mm-hmm.

Brian Cox 32:12 ... dollar industry, you know, with communication, satellites, and weather satellites, GPS, whatever, yet we're already up there. And so learning to live and work in space is, I think, a natural extension of our, of our civilization. Plus the fact if you talk to Elon or Jeff Bezos, they point out that the, the amount of resources available just slightly above our heads is vast. And so I, I remember I talked to Jeff Bezos actually once, and he, he thinks really simply, and he said, you know, "For example, in the asteroid belt, there's enough metal, I think, to, to build a skyscraper s- what is it? Eight- uh, something like 800 stories tall and cover the Earth in it, right? (laughs) If you want." Now, we don't wanna do that, but his point was that, that the energy from the sun is all up there, the resources are up there, so 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. And th- these sound, it sounds like science fiction, except that now SpaceX and Blue Origin, those people have got reusable rockets. So suddenly, the economics become sensible. So I think it... I think, I think expansion is good, and I think we will expand, and I think we will expand outwards because there's not much room left on this planet to expand, so I think we'll do... So it... But it's a... That's a whole different idea. It's, it's not about gathering scientific information. It's about a frontier an- and all the benefits that come from operating as a civilization on a frontier, which we've, have lost on the Earth because there is no frontier left. And so I like that idea.

Joe Rogan 33:47 Mm-hmm.

Brian Cox 33:48 That Mars... And w- when you talk about Mars, especially with Elon, he's right that that's the only place you can go. So there, there is no other planet we can go to other than Mars. Uh, you can't go to Jupiter or Saturn.

Joe Rogan 33:59 Right.

Brian Cox 33:59 You can't go to Mercury or Venus. So if we wanna go somewhere and expand our civilization, it has to be Mars, and everything's there that you need. So, but that, that's a different thing saying that you wanna find out stuff. You're right, if we just wanna find out stuff, then you send robots.

Joe Rogan 34:13 But 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.

Brian Cox 34:22 (laughs)

Joe Rogan 34:22 Total... I mean, you, you're gonna live on Mars? I wouldn't.

Brian Cox 34:25 I, I agree with you.

Joe Rogan 34:26 I wouldn't. Yeah.

Brian Cox 34:26 It's... Uh, it'd be a hor- horrendous thing. It's, it's like the... A bit like the Western Front. Yeah, it's the frontier when people cross the states.

Joe Rogan 34:33 Yeah.

Brian Cox 34:33 An incredibly dangerous thing to do, but it's far-

Joe Rogan 34:36 But when people crossed the states, they still got to Wyoming and beautiful places and Colorado and...

Brian Cox 34:42 Yeah, but it was hard.

Joe Rogan 34:43 Yes.

Brian Cox 34:43 I wouldn't have wanted to do it.

Joe Rogan 34:44 But once you got there, there's a river and there's trout in the river and the, the meadows are green and...

Brian Cox 34:50 It's, it's right... I mean, (laughs) I, I agree with you, right? I mean, the... I'm not gonna go there 'til there are vineyards and-

Joe Rogan 34:54 Yes.

Brian Cox 34:54 ... hotels and things, but however (laughs) , uh, it is true that there are people who like the challenge. And what is true about Mars, it's interesting actually, 'cause w- we know something about the history of Mars now, quite a lot about the history of Mars, and it's certainly clear that there was water, almost certainly oceans and rivers. So... And that water is almost certainly still there. So I would say certainly still there.

Joe Rogan 35:19 Well, they have found large quantities of ice now, right?

Brian Cox 35:22 Yeah. So there's certainly ice. There may even be pockets of liquid water below the surface somewhere. So, um, couple that with all the, the minerals and the resources that we know are there, and you have everything you need. So that's the thing about Mars. It's, it's quite nice relative to everywhere else other than the Earth. You, you can't go to Venus, right?

Joe Rogan 35:42 Right.

Brian Cox 35:42 You, you'd just melt. It's... What is it? 400 and something degrees and, uh, 90 atmospheric pressure.

Joe Rogan 35:48 Yeah.

Brian Cox 35:48 And, and so that... So, so, so Mars is quite nice, um, but I wouldn't go there. I agree with you 'cause it's not habitable.

Joe Rogan 35:55 And what's the gravity of Mars in relationship to the Earth?

Brian Cox 35:57 It's, um... What is it? About a third, I think.

Joe Rogan 35:59 A third of it, right?

Brian Cox 36:00 Yeah, something like that.

Joe Rogan 36:00 So it would still have a, a significant, like, weakening effect. Like, if you went to Mars and then somehow or another in the future that they were able to get back to Earth-

Brian Cox 36:08 Yeah.

Joe Rogan 36:09 ... your body would have a, a real problem with that, right?

Brian Cox 36:11 It would, but there, there is, there is still grav... No, it's a bit more than a third. I can't quite remember, but it's something like that. But yeah, so y- i- there's still gravity.

Joe Rogan 36:19 Right.

Brian Cox 36:19 So there's gravity. There's, um, some protection from th- th... You'd probably want to live in the caves actually or something like that 'cause th- th- there's no magnetic field there.

Joe Rogan 36:29 Right.

Brian Cox 36:29 So it's quite a high radiation environment, but not too bad. It's further from the sun than we are. It's not too... There are places on Mars... There, there's a very deep crater called Hellas, which is a big impact basin. And at the bottom, the, the... It's so deep-You could fit Everest in it. So you put Mount Everest in there-

Joe Rogan 36:48 Oh.

Brian Cox 36:48 ... the summit of Everest wouldn't reach the rim of the crater. So it's, it's something like, I don't know what it is, 7 miles deep or something.

Joe Rogan 36:54 Wow.

Brian Cox 36:54 6 miles deep. So you could go there, and at the bottom, the, the atmospheric pressure's so high that you could just about have liquid water, on... Occasionally on the floor of that crater.

Joe Rogan 37:06 So they wouldn't go?

Brian Cox 37:06 And it's quite warm sometimes. It can be 20 degrees.

Joe Rogan 37:09 Really?

Brian Cox 37:09 Yeah, (laughs) there. Celsius. Um-

Joe Rogan 37:12 Wo- Wow.

Brian Cox 37:12 So, so occasional-

Joe Rogan 37:13 That's better than Minnesota right now.

Brian Cox 37:14 Exactly, so-

Joe Rogan 37:15 Minnesota's experiencing a serious cold front.

Brian Cox 37:16 (laughs) That's right, yeah. So it can be warmer than Minnesota and, uh... So, so there are places where, where it's not horrendous on Mars. Uh, you know, so The Martian is, is kinda realistic in that sense.

Joe Rogan 37:30 Sort of?

Brian Cox 37:31 Bits of it.

Joe Rogan 37:31 Do you watch those movies-

Brian Cox 37:33 (laughs)

Joe Rogan 37:33 ... and shake your head?

Brian Cox 37:34 I quite... I like them. I just-

Joe Rogan 37:35 Do you?

Brian Cox 37:35 I, I like science fiction, you know?

Joe Rogan 37:36 Right.

Brian Cox 37:37 I, you know, so, yeah, I don't sit there... I, I grew up with Star Wars. That was my... When I was nine years old or something like that. So I don't sit there going-

Joe Rogan 37:43 It's funny watching it now.

Brian Cox 37:43 I just don't... Yeah, I'm not having this.

Joe Rogan 37:46 (laughs)

Brian Cox 37:46 I did, I had a, an argument with Neil deGrasse Tyson... Not an argument, but a debate with him about lightsabers once. 'Cause I claim that they're physically po-... That in principle, they're possible. Um, and he was trying to say that they aren't, but they are.

Joe Rogan 37:58 Would it have to loop back around 'cause the light's not continuing to-

Brian Cox 38:02 It-

Joe Rogan 38:02 Like, the fact that it goes to a certain distance and pauses?

Brian Cox 38:06 Well, you'd have to have a mirror or something, I guess, yeah.

Joe Rogan 38:08 Something would have to-

Brian Cox 38:08 That's true.

Joe Rogan 38:08 ... be the end of it, right?

Brian Cox 38:09 That's true. So it wouldn't... It, it would be a different kind of lightsaber. The, the only point I was making is that photons, particles of light, can bounce off each other.

Joe Rogan 38:17 Hmm.

Brian Cox 38:17 So we see that in really high-energy experiments in particle accelerators, we can collide photons together. So my point was a bit of a pedantic physicist one, but it is... 'Cause it, it is true that light can bounce off. It can hit light-

Joe Rogan 38:32 Right.

Brian Cox 38:32 ... but very, very high energy.

Joe Rogan 38:34 But when they press that button, it goes to a certain distance.

Brian Cox 38:37 Yeah, yes, yeah. I wasn't... That's engineering.

Joe Rogan 38:40 Right.

Brian Cox 38:41 (laughs) No, I agree with you. I agree with you. The distance thing doesn't work.

Joe Rogan 38:44 Well, there's also-

Brian Cox 38:44 Yeah, I agree. (laughs)

Joe Rogan 38:44 There's no mass to it, right? So as you're swinging it around, you wouldn't have the-

Brian Cox 38:50 (laughs)

Joe Rogan 38:50 ... leverage of a long thing, so why not make it really long? 'Cause it wouldn't be difficult to swing around. Like you could stab someone with a lightsaber a mile away.

Brian Cox 39:00 That's true, (laughs) yes.

Joe Rogan 39:01 Right?

Brian Cox 39:01 True. Well, that's just a laser, isn't it?

Joe Rogan 39:03 Yes. Like why-

Brian Cox 39:04 I suppose.

Joe Rogan 39:04 Why make it so short?

Brian Cox 39:05 Yeah, exactly. (laughs)

Joe Rogan 39:06 It's ridiculous. You have to swing... You have to be close to hit e- a person with it.

Brian Cox 39:09 Yes.

Joe Rogan 39:10 That's a silly, silly design.

Brian Cox 39:12 You, you are picking holes correctly in the engineering part of my-

Joe Rogan 39:16 (laughs)

Brian Cox 39:17 The only point I was making is the physics is that, which I think is quite, uh, interesting, is that light can bounce off light.

Joe Rogan 39:23 Yes.

Brian Cox 39:24 That's the point, but-

Joe Rogan 39:25 So, but it would have to... There would have to be something that causes it to stop at the very end.

Brian Cox 39:29 Yeah.

Joe Rogan 39:30 Yeah.

Brian Cox 39:30 Yeah. Which would be... You're right. It'd have a mirror, but it wouldn't look cool, would it? If there was a-

Joe Rogan 39:34 No.

Brian Cox 39:35 ... kind of thing with a mirror. (laughs)

Joe Rogan 39:36 Well, what drives me crazy about Star Wars is not the lightsabers, it's the lasers when they're shooting the guns. I'm like, "Why can I see that, but I can't see bullets?"

Brian Cox 39:46 Yeah.

Joe Rogan 39:46 This is supposed to be way faster than a bullet.

Brian Cox 39:49 Yeah. (laughs) Like a space fighter.

Joe Rogan 39:49 Why is it easy to see this?

Brian Cox 39:51 (laughs)

Joe Rogan 39:51 'Cause it's like... You could duck. You could get out of the way of those things.

Brian Cox 39:54 They're really slow, aren't they?

Joe Rogan 39:55 They're so slow.

Brian Cox 39:56 (laughs)

Joe Rogan 39:56 I would be so angry. I'd be like, "This is so dumb. I 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?"

Brian Cox 40:08 Yeah.

Joe Rogan 40:08 "That's so dumb."

Brian Cox 40:08 And it's not only Star Wars, is it? It's everything.

Joe Rogan 40:10 (laughs)

Brian Cox 40:11 Every single film does that.

Joe Rogan 40:12 Yeah.

Brian Cox 40:13 Yeah.

Joe Rogan 40:14 Why?

Brian Cox 40:15 Well, it's like, it's like films like... Also, I worked on one of these films years ago. Uh, Sunshine.

Joe Rogan 40:20 Oh, that was a great movie.

Brian Cox 40:22 With Danny Boyle. Very, very-

Joe Rogan 40:23 Very underappreciated movie.

Brian Cox 40:24 Yeah, I think so. I think it's-

Joe Rogan 40:25 Yeah.

Brian Cox 40:25 ... a brilliant film. But in that, so they, they asked me, or Danny said, "I wanna do it right, so I'll do the spacecraft without any sound. So when it's traveling through space, it'll be silent."

Joe Rogan 40:35 Oh.

Brian Cox 40:35 And it looks shit.

Joe Rogan 40:37 Oh.

Brian Cox 40:37 You know, just when you watch it.

Joe Rogan 40:38 Yeah, yeah, yeah.

Brian Cox 40:39 It's the same when, when you try and film astronauts and you... And they're in zero G and they always move slowly.

Joe Rogan 40:44 Mm-hmm.

Brian Cox 40:44 It's like, "Why?" You know, you're right. You don't-

Joe Rogan 40:46 Right, you'd be able to move very fast.

Brian Cox 40:48 ... move as fast as you want.

Joe Rogan 40:48 Yeah.

Brian Cox 40:49 But it looks silly.

Joe Rogan 40:50 Ah.

Brian Cox 40:50 So there's kind of a, a... I suppose it's what audiences have got used to over the years, and so in the end, you have a... And the spacecraft goes past.

Joe Rogan 40:59 Right.

Brian Cox 40:59 Apart from 2001, which didn't do it.

Joe Rogan 41:02 Yeah.

Brian Cox 41:02 It was silent in 2001.

Joe Rogan 41:04 Well, Kubrick was a stickler for science and for... He, he was apparently... He would do complex mathematics in his spare time. What a fascinating guy-

Brian Cox 41:13 Yeah.

Joe Rogan 41:14 ... that must've been.

Brian Cox 41:15 Yeah. I read that they just, um... Someone just found an interview, didn't they, the other day, where he explained the ending of 2001.

Joe Rogan 41:22 Oh, I didn't see that.

Brian Cox 41:23 I saw, I saw it yesterday actually. And it was, it was kind of a really simple version of it. He 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."

Joe Rogan 41:39 Wow.

Brian Cox 41:40 That's the, that's the worst explanation at the end of 2001 I've ever heard. But it was Kubrick's. That's what Kubrick said, so the... He falls into the monolith, yeah, that they just put him in this room which is kind of a bad version of a French chateau or something, watch him grow old, and then send him back to the Earth as a super being.

Joe Rogan 41:59 Wow. Okay.

Brian Cox 42:00 That was Kubrick's-

Joe Rogan 42:01 Yeah.

Brian Cox 42:02 ... version. I guess.

Joe Rogan 42:03 How strange. It's, uh, it's a, it's a weird genre, right? Because sometimes people get things right. Like, didn't H.G. Wells predict, uh, a significant amount of scientific inventions in the future?

Brian Cox 42:17 Um... Well, there was... I mean, it depends which one, doesn't it? There was a moon one, wasn't there? He did a, a journey to the moon. I mean, his time machine is-

Joe Rogan 42:25 Yes.

Brian Cox 42:25 ... not-

Joe Rogan 42:25 Right, that one hasn't-

Brian Cox 42:26 We're not gonna be able to do that.

Joe Rogan 42:27 ... really worked out yet. (laughs)

Brian Cox 42:29 No. (laughs) But, but yeah, I think it's... I, I always liked science fiction.

Joe Rogan 42:34 Yeah.

Brian Cox 42:34 I like Arthur C. Clarke a lot, you know, 'cause I, I think it is... You're right, it's, it's a-... a, a form that you can let your imagination wander and address things-

Joe Rogan 42:44 Yeah.

Brian Cox 42:45 ... without restriction, I think.

Joe Rogan 42:46 Did you like the Alien series?

Brian Cox 42:48 I loved it.

Joe Rogan 42:48 Yeah, me too.

Brian Cox 42:49 I saw Alien when I was... Uh, when I was at school, it was 1979, right, and we had a school film club. And in the '70s, they weren't like they are now, you know? And the... So the first films they put on, the three films, I was 11 and it was Alien, Apocalypse Now, and Life of Brian.

Joe Rogan 43:03 Wow.

Brian Cox 43:04 Which I... So that was my introduction to (laughs) to cinema.

Joe Rogan 43:07 Wow. Well, those are three great choices.

Brian Cox 43:09 Uh-huh.

Joe Rogan 43:09 But I, I feel like Ridley Scott's original Alien is probably one of the greatest horror/science fiction movies of all time.

Brian Cox 43:16 Yeah, I'm agree-

Joe Rogan 43:16 And one of my all-time favorite movies.

Brian Cox 43:18 Completely.

Joe Rogan 43:18 But I really like the newer ones as well, like Pro... I liked Prometheus and I really liked Covenant, the, the last one.

Brian Cox 43:24 Yeah, Prometheus, I don't know, I, I, I do.

Joe Rogan 43:26 Yeah, it's not the best one. I like what they're trying to do with it. The, the whole idea about the engineers coming back in time and-

Brian Cox 43:32 That's, that's wh- that's why I was disappointed with it, 'cause I thought the setup, the opening is brilliant.

Joe Rogan 43:37 Mm-hmm.

Brian Cox 43:37 And I thought, "This is just going to be brilliant."

Joe Rogan 43:40 Right.

Brian Cox 43:40 And then I thought it just lost its way and it was a-

Joe Rogan 43:43 Yeah.

Brian Cox 43:43 ... disappointment-

Joe Rogan 43:44 Yes.

Brian Cox 43:44 ... because it could've been so brilliant, I think.

Joe Rogan 43:46 Yes, I agree with you. Yeah, the beginning was fantastic. But I think Covenant was more, more exciting. And, well, but it's also preposterous. Like, if you went to another planet, like, the last thing you'd be doing is just breathing in the air, right? I mean, we'd have to be really c... If there was a life on the planet, we'd have to be really careful a, not to contaminate, but b, not to be contaminated, right?

Brian Cox 44:08 Yeah, y- yeah.

Joe Rogan 44:09 I mean, the-

Brian Cox 44:09 Yeah.

Joe Rogan 44:10 ... there's also... I mean, you know, the other thing in science fiction films is gravity, 'cause it, you always- Yeah.

Brian Cox 44:15 ... even in Alien, you always just say the spaceship's got gravity.

Joe Rogan 44:18 Right.

Brian Cox 44:18 Again, there's only 2001-

Joe Rogan 44:20 Right.

Brian Cox 44:20 ... where everybody floats around.

Joe Rogan 44:22 Yeah.

Brian Cox 44:22 Because all has a spinning thing to it.

Joe Rogan 44:24 Right. The spaceship has gravity and then when you land, the gravity's exactly like Earth.

Brian Cox 44:28 Yep.

Joe Rogan 44:29 Perfect.

Brian Cox 44:30 Yeah.

Joe Rogan 44:30 But it's-

Brian Cox 44:30 You know... (laughs)

Joe Rogan 44:31 ... it's ridiculous. Yeah. I mean, would, uh... What are the odds that you would find a planet that is exa... Like, even if a planet was one and a half times the size of Earth, it would have far more gravity, right? And that's, that's really common for a planet to be, like, just a little bit bigger.

Brian Cox 44:46 Yeah.

Joe Rogan 44:46 And then we would be like, "Fuck," everywhere we'd be walking, we'd be w- we'd be getting crushed, right?

Brian Cox 44:51 (laughs) Right. I agree with you.

Joe Rogan 44:53 Yeah. But-

Brian Cox 44:53 But I suppose that's not the point. It's about ideas, isn't it, science fiction?

Joe Rogan 44:56 Yes, and, you know, this whole idea where you're just supposed to let it, let the, you know, let the story play out and, and-

Brian Cox 45:04 Yeah. Well, I mean, Sunshine was, um... You know, the pre- the premise is, is silly. I mean, it's, the premise is the sun is dying and we're gonna go and fix it.

Joe Rogan 45:15 Yeah. (laughs)

Brian Cox 45:15 So both of those things... It fails on its first line-

Joe Rogan 45:18 Right, right, right.

Brian Cox 45:19 ... in, in terms of realism. But the idea is that it's not about that. It's about, um, it's about the, it's about the sun as a god in some ways, so it's about our response to the power of nature. And it's about deifying this thing and worshiping it and how ultimately you go mad. If you remember the film, there's Pinbacker, who's the first captain that went to the... Captain, the first mission to go and restart the sun, which is the mad bit.

Joe Rogan 45:44 Mm-hmm.

Brian Cox 45:45 But then became a religious fundamentalist, essentially, and then decided... It's a fascinating idea that he decides that to bring meaning to his life, he will become the last, last man, the last human. And so he wants to be the last, he wants the sun to die, and he wants it to take humanity with it. And he decides to make that happen, so he stays there waiting for the second ship.

Joe Rogan 46:11 Mm-hmm.

Brian Cox 46:11 And I like those ideas that, you know, that what, what's your reaction to the power of nature? And this happens in... It's one of the things I do in my shows, I'm not being a commercial person, I've just thought of it. (laughs) One of the great things about cosmology is that it is terrifying in the, in the truest sense of the word. I mean, we talked a bit about the size and scale of the universe and black holes colliding and those things. You know, it is very frightening, but also the, I think the, the act of trying to understand our place in nature and the size and scale of the universe and our, our, you know, tiny presence within it is valuable. It's a, it's a... So that you can be terrified, but also inspired and interested. And it's part of... If you want to find... If you wanna 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 of pow- powers in the universe that we cannot comprehend, as you said. But that, tha- that's what you've got to face, because that's reality, so you can't hide your head in the sand and just duck it. And it sends some, it can send some people crazy.

Joe Rogan 47:26 I'm sure. And it is really interesting that we need that suspension of disbelief in order to sort of make a film on space. You, you, you almost have to, like, go, "Well, this isn't really how it'd be, but this is how you have to make it in order to fit it into a two-hour movie."

Brian Cox 47:43 Yeah. And then, and then the film, as with Sunshine, becomes about... Then you can have the film about something else.

Joe Rogan 47:49 Yes.

Brian Cox 47:49 'Cause it's not really about that.

Joe Rogan 47:51 Yes. Well, did you like Event Horizon?

Brian Cox 47:53 Yeah, I did actually. I thought that was quite a cool film.

Joe Rogan 47:56 It was fun, right? It's ridiculous, but-

Brian Cox 47:56 Yeah.

Joe Rogan 47:56 ... I haven't seen it for years.

Brian Cox 47:57 ... but fun. Yeah.

Joe Rogan 47:58 I always wanted to ask about their, their concept of propulsion, that you, uh, 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-

Brian Cox 48:11 Mm-hmm.

Joe Rogan 48:11 ... instantaneously, right? And I'm doing a terrible job of explaining it, I'm sure. But is that a, a concept that people have actually considered?

Brian Cox 48:18 Yeah, you can... In, in general relativity... So, so Einstein's... I should say what it is. Uh, Einstein's theory of general relativity is our best theory of space and time. And so it really is... As we've talked about before, it's you imagine space and time as a sheet. Just imagine it as a thing, sort of a, a literally a sheet surface. And 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.And so it's the response of space and time to matter and energy. So if you, if you... The- the simplest version would be the- the sun. So you put the- a big spherical ball of stuff in there, and it- it warps space and time such that the nice straight lines, something just traveling, minding its own business through that warped space, turns into an orbit.

Joe Rogan 49:08 And that's why you can actually-

Brian Cox 49:09 And that-

Joe Rogan 49:09 ... kind of see things that are behind the sun?

Brian Cox 49:12 Yeah.

Joe Rogan 49:12 Okay.

Brian Cox 49:12 So light bends around the sun-

Joe Rogan 49:15 Okay.

Brian Cox 49:15 ... um, because it's just traveling through the curved space. The Earth goes round the sun because it's just rolling, minding its own business through the curved space. So, um, an example would be, you might say, "Well, how does curved space, how- how does, can that give rise to something that looks like a force, which is gravity?" So the best analogy I know of is to think of walking around on the surface of the Earth. So if you stand on the equator of the Earth, and you- you, with your friend, and you- you say, "We're gonna walk due north, so we're gonna set off..." Let's say we're 1,000 miles apart on the equator and we're gonna walk due north. What's gonna happen? So you walk in straight lines. You don't change direction, you don't do any accelerating. But the straight lines are the lines of longitude on the surface of the Earth. So as you go further and further north, you get closer and closer together. And if you carry on to the pole, you bump into each other.

Joe Rogan 50:03 Hmm.

Brian Cox 50:04 But nothing's happened, right? No one's... no one... there's no forces acting. It's just that you're moving on a curved surface, and so you get closer. And that's basically Einstein's theory of general relativity. Now, why did I start talking about that?

Joe Rogan 50:17 Event horizon, the idea of, uh, folding.

Brian Cox 50:19 Oh, yeah. So- so you can... So all you have to do so that there's folded kind of geometries, is you have to try and specify how, where you would put the matter and what kind of stuff you'd put there to make the geometry fold in that way. And you can do, you can do it. So you can, you can write down that geometry. So it's called a- a warp drive geometry, I think it's called. It's in textbooks. So you can do that to- to have a warp drive. The question becomes, what sort of stuff would you have to actually put into the real universe to make it warp in that way? And, um, it- it always, it usually turns out that it's the kind of stuff that doesn't exist.

Joe Rogan 51:00 Right. (laughs)

Brian Cox 51:01 (laughs) But it has properties. It's ma-

Joe Rogan 51:02 Right.

Brian Cox 51:02 ... sort of matter or sort of energy that has properties that do not exist in nature as far as we can tell. But you can still write the geometry down in Einstein's theory. So if you have the stuff-

Joe Rogan 51:13 So if you had a significant force or mass or whatever it is, if you had that-

Brian Cox 51:16 Yeah.

Joe Rogan 51:16 ... stuff that doesn't exist, it is a concept that- that- that could be implemented.

Brian Cox 51:19 Yeah. So the geometry exists. So-

Joe Rogan 51:22 Right.

Brian Cox 51:22 So you can, you can, you can do it and you can do the calculations and you can see the warp drive. You can construct wormholes that connect distant regions of the universe, which you could use as time machines. Um, you can do all that in the theory. But in nature, you'd have to have the right stuff to do it.

Joe Rogan 51:39 But that stuff is not real-

Brian Cox 51:40 That seems to be the case.

Joe Rogan 51:41 ... as far as we know.

Brian Cox 51:42 Yeah.

Joe Rogan 51:42 Now, what would have to happen? Like, the, you would have to have a- enough power or mass to- to- to be able to fold those two things together? Like...

Brian Cox 51:51 It tends to be weird stuff like, um, stuff that has a negative pressure or something like that. So stuff that has physical properties that are just bizarre, and- and that no matter or energy that we know of in the universe has. So that- that... to make, to make the geometry happen.

Joe Rogan 52:09 But it's conceivable in theory that this could exist, even though it doesn't?

Brian Cox 52:15 It's a- it's a- it's a debate ultimately. Um, so wormholes are a good example. So that would be... quite literally, it was talked about the surface of the Earth. So you fly to Australia from LA and you have to go quite a long way around the s- edge of the Earth. Or you could tunnel straight through and get there quicker, right? (laughs)

Joe Rogan 52:33 There we go.

Brian Cox 52:33 So you can... That- that's a wormhole.

Joe Rogan 52:34 Jamie's got a little graphic up there on the-

Brian Cox 52:36 There it is.

Joe Rogan 52:37 ... screen for us.

Brian Cox 52:37 There's a wormhole. So you could go all the way around the edge, or you could cut- take the shortcut.

Joe Rogan 52:41 Mm-hmm.

Brian Cox 52:42 So the question is... So you can do that in Einstein's theory, you can write down that geometry, and- and there it is. So the first question is, can you make it? And- and as we said, we- we don't think that stuff exists.

Joe Rogan 52:53 Right.

Brian Cox 52:53 There's a second set of theoretical, bits of theoretical work which are, if you had a wormhole, then what would happen if you tried to travel through it? And what seems to happen is that- is that they become unstable the moment anything tries to go through. So you get kind of a feedback of stuff going through-

Joe Rogan 53:13 Ah!

Brian Cox 53:13 ... and through and through and through. And so it collapses. And there- there's a great, there's a great book by Kip Thorne actually. We just mentioned him. He got the Nobel Prize last year for the gravitational waves. And he wrote a brilliant book, I think it's in the '80s, called Black Holes and Time Warps, where he talks about the... The answer is we don't fully know, but most physicists think that even if they existed, they would be unstable. And as soon as you even try to transmit information through them, send a bit of light through, then there would be this feedback and they'd collapse. And- and ultimately, the reason we don't really know absolutely is because you need what's called a quantum theory of gravity, and we don't have one. So we don't have the theoretical tools to be absolutely sure that these things would be unstable or- or don't exist in nature. But we strongly suspect that they don't. If they did, you could build a time machine. So... There- Stephen Hawking wrote a paper called The Chronology Protection Conjecture. Um, and conjecture is the important word. So he... uh, the- 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. And-

Joe Rogan 54:22 And if you sent something through it, it would destabilize it.

Brian Cox 54:24 Yeah.

Joe Rogan 54:25 And if it didn't destabilize it, how would your physical body deal with the stress of that?

Brian Cox 54:31 Well, it doesn't have to be. The... You can, you can build them. That's called the tidal gravitational force, so it'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. So before (laughs) you actually get to the s- singularity, you can get... it's called spaghettified. It's a technical word. (laughs)

Joe Rogan 54:49 (laughs)

Brian Cox 54:49 So you get... And it's just like the moon's, you know, the tidal effects on the Earth, which are-

Joe Rogan 54:53 Mm-hmm.

Brian Cox 54:54 ... quite small, but they still raise tides on the oceans. So that can be a... i- if you think about something like a black hole, that can be a massive difference in gravitational pull from your head to your feet, and so it can stretch you out. And so... But you can... With wormholes, you- you can, you can write the geometry down in Einstein's theory such that you could go through.

Joe Rogan 55:15 ... so-

Brian Cox 55:15 Uh, so you don't have to be destroyed or anything weird happen to you.

Joe Rogan 55:19 Would you have to have some- something protecting you? Some force? Some, some sort of a-

Brian Cox 55:25 No. You just literally, you fall through. I mean, so, so, you know, i- if they were, if you, they exist, you just, you just go through. Yo- well, you sit in a little spaceship, but you, you, you wouldn't... There's nothing inherently in them that says that you would be ripped apart-

Joe Rogan 55:41 Right.

Brian Cox 55:41 ... or anything like that. But-

Joe Rogan 55:44 What are your thoughts on, on alien life, on life outside of this planet?

Brian Cox 55:51 I-

Joe Rogan 55:51 Is that something you think about?

Brian Cox 55:52 Yeah. I, I think there must be, um, even 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.

Joe Rogan 56:05 Like Europa?

Brian Cox 56:06 Yeah. And the reason is, if you think about... The reason I think that, and it's a guess, is because if you look at the history of life on Earth, then... So Earth formed and it was just a, a... There was no life, it was a ball of rock. And almost as soon as it cooled down, we see evidence of life. So certainly 3.8 billion years ago, possibly even further back than that, we see evidence of life on Earth. So somewhere along the line, geochemistry, active geochemistry, became biochemistry on Earth. And we have some idea, you know, that, that if you get s-, uh, 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. So we have a... We know that life... Almost certainly we know that life began on Earth. I mean, the oth- the other option is it came from space or something like that, but it probably didn't (laughs) , right? It probably began on Earth. Um, so that means that, at least here, that happened, and that we know that the conditions that led to the origin of life on Earth were present on Mars 3.8-4 billion years ago, and we know that they're present on Europa today. So I don't see that there's anything special. Life is just chemistry, and it... Uh, and the, the idea that geochemistry becomes biochemistry is not fanciful because it happened here. So I think that given the same conditions, it would be surprising to me if the same thing didn't happen, in that life begins. So I, I... That's one of the... To test that is one of the great frontiers of science now. It's one of the great challenges, which is why w- another reason we're interested in Mars, because we know those conditions were there. We know there were what's called hydrothermal vent systems on the floors of oceans on Mars 3.8 or 4 billion years ago, so it would be good to know if what I've said is right. And the, the way we find out is to find life or evidence of past life.

Joe Rogan 58:12 Uh, d- are you aware of, uh, the speculation that was going around? Wh- how, how recent was it, that octopi thing, the oc-, uh, uh, the oc- octopus eggs? They, there was a group of scientists that were speculating that it's pos- you know, panspermia, the idea of panspermia?

Brian Cox 58:28 Yeah, yeah.

Joe Rogan 58:29 That it's possible that octopi had come from somewhere else, some frozen eggs had actually come from somewhere else and, and landed on Earth. And these were, like, legitimate scientists who were contemplating, not morons.

Brian Cox 58:40 I, I don't think-

Joe Rogan 58:41 You've seen this?

Brian Cox 58:43 The... No, I didn't, but I mean, it, I think it's unlikely. So panspermia doesn't have to be unlikely.

Joe Rogan 58:48 Right. Sure.

Brian Cox 58:48 I mean, for example, you might have seen the other day we found an Earth rock on the moon.

Joe Rogan 58:51 Yes.

Brian Cox 58:52 Right. Well, the, well, it's back on Earth now-

Joe Rogan 58:53 Yeah. Right.

Brian Cox 58:53 ... 'cause the Apollo astronauts brought it back, didn't they? And it's 4 billion years old or something like that.

Joe Rogan 58:57 One of the oldest rocks ever found.

Brian Cox 58:58 Yeah.

Joe Rogan 58:59 Right.

Brian Cox 58:59 So, so we know that material gets transferred between planets. Um, and so it's not inconceivable that microbes could survive that journey, right? We know that microbes can survive in space, for example. So that isn't mad. Uh-

Joe Rogan 59:14 Right.

Brian Cox 59:14 ... it's, it's probably unlikely, but it's not mad. But with the octopus, I hadn't heard that. But the thing is that the octopus is still extremely similar biologically to us. I mean, the differences are negligible.

Joe Rogan 59:25 Yeah.

Brian Cox 59:25 So it's still got the same energy system with single ATP and DNA and all that stuff. It's all very, very similar.

Joe Rogan 59:31 It was something about RNA and DNA. Did you, did you find that article?

Narrator 59:34 Yeah. I'm trying to f- I'm looking at a different one from a different website.

Joe Rogan 59:37 Sorry.

Narrator 59:37 It's about the same thing. It has-

Joe Rogan 59:38 Di-

Narrator 59:38 ... to do with the Cambrian explosion and th- there were 33 authors on a paper that got published in the Progress in, in Biophysics and Molecular Biology that talked about this possibility. There are other people that disagree with it though.

Joe Rogan 59:51 Right.

Brian Cox 59:51 I mean, th- I suppose the... I haven't seen it yet, so I think it's unlikely because the octopus is extremely similar to us, so that suggests a common origin to me. Now, I suppose the counter argument you could, you could advance would be, there's only one way to do life-

Joe Rogan 1:00:06 Hmm. Right.

Brian Cox 1:00:06 ... so you could say that actually given... Because the laws of physics and chemistry are the same everywhere, so maybe it's, maybe DNA wi- th- is the only way to do it, so that's the way it gets done. So you-

Joe Rogan 1:00:18 Which is why they're so similar to us.

Brian Cox 1:00:20 Yeah. See-

Joe Rogan 1:00:20 Although so alien as well.

Brian Cox 1:00:23 Yeah. They're, they're not though. You know, that's the thing about an octo- (laughs) that's why I'm surprised about it, because they're not that alien. They- they're very similar.

Joe Rogan 1:00:30 Well, they are in their abilities. I mean, their ability to transform their out- outer texture and their color inst- almost instantaneously.

Brian Cox 1:00:37 Oh, yeah.

Joe Rogan 1:00:38 I mean, they have incredible camouflage abilities that really don't exist-

Brian Cox 1:00:41 Yeah.

Joe Rogan 1:00:41 ... in the mam- mammalian world.

Brian Cox 1:00:44 Yeah. But on a cellular level, you look at an octopus cell in a, under a microscope and you wouldn't be able to tell the difference-

Joe Rogan 1:00:49 Right.

Brian Cox 1:00:49 ... between an octopus cell and a human cell.

Joe Rogan 1:00:51 So 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?

Brian Cox 1:01:00 I'm, I'm guessing, but-

Joe Rogan 1:01:01 Right.

Brian Cox 1:01:01 ... yes, that, that, that must be the, uh, the only way you could sustain that, given that they're so similar to us, because they really are biochemically.

Joe Rogan 1:01:09 Hmm.

Brian Cox 1:01:10 ... is that? That's the only way it can be done, given the, given the building block, the toolkit, the laws of nature, and the, the elements and so on that we have in our universe.

Joe Rogan 1:01:19 We 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.

Brian Cox 1:01:29 Yeah.

Joe Rogan 1:01:29 Like, if we sa- if we found a frog on the moon, I mean-

Brian Cox 1:01:32 (laughs)

Joe Rogan 1:01:32 ... the, the world would stop, right?

Brian Cox 1:01:34 I'd be very surprised if we found a frog on the moon. (laughs)

Joe Rogan 1:01:36 Right? But also, I mean, if we found anything anywhere that is any, in any way similar-

Brian Cox 1:01:40 Well, th-

Joe Rogan 1:01:40 ... An insect on Mars.

Brian Cox 1:01:42 Well, this is, I mean, it, as I said, it'd be micro, I think it'd be single-celled things. Remember, I mean, you mentioned the Cambrian explosion.

Joe Rogan 1:01:49 Right.

Brian Cox 1:01:49 So that is the, 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 that, or, or maybe at most 700, that you see any complex multicellular organisms at all. So for something like three billion years, it was single-celled alone. And that's one of the reasons why I would guess, if, if I had to guess, I would say that microbes would be common because life began very quickly on Earth, and I wouldn't be surprised if we find it on Mars. But complex life, multicellular life, insects, plants, intelligence, I would guess, would be very rare because it took so long on Earth to get there. I mean, just-

Joe Rogan 1:02:34 Mm-hmm.

Brian Cox 1:02:34 ... slime.

Joe Rogan 1:02:35 Right.

Brian Cox 1:02:35 About three billion years of slime was there.

Joe Rogan 1:02:38 (laughs)

Brian Cox 1:02:39 That was it on Earth.

Joe Rogan 1:02:40 What happened? (laughs) How did it go from slime to giraffes?

Brian Cox 1:02:44 It's, uh, well, i- it did it very quickly-

Joe Rogan 1:02:45 (laughs)

Brian Cox 1:02:46 ... once it, once it got going.

Joe Rogan 1:02:47 Yeah.

Brian Cox 1:02:47 And it's one of the great unsolved, uh, mysteries in biology that one thing that is true is that we seem to be, all complex creatures seem to be, um, we're, we're called eukaryotes, right? Which are cells with a cell nucleus and all that kind of stuff. And they look like they're the merger between two simpler life forms, bacteria and a thing called an archaea, an archaean. So it looks like somewhere in, two billion years ago, whatever it was in some ocean, the bacterium cell got inside the archaean and survived as, as a symbiotic organism essentially, and then somehow, unbelievably, managed to re- reproduce and replicate in that configuration. And that does seem to be the origin of all complex multicellular life on Earth. So it's called the fateful encounter hypothesis. And, uh, if that's true, then it's just a bit of luck, and it happened once, right? (laughs) And that's why we're here.

Joe Rogan 1:03:50 Now, when you-

Brian Cox 1:03:50 A blind look.

Joe Rogan 1:03:51 ... consider, like, how many billion Earth-like planets did you say exist just in our-

Brian Cox 1:03:56 Th-

Joe Rogan 1:03:56 ... solar system alone?

Brian Cox 1:03:57 In, in the galaxy, 20 billion, something like that, so one in 10 stars.

Joe Rogan 1:04:01 So the odds of complex life out of our incredibly fortunate situation, but the odds of that occurring on any of these billions of other planets that exist?

Brian Cox 1:04:11 Well, we don't know, but let, let's say the Earth is, let's say it was on the fortunate side. So, so we- we're, we're talking about ro- give or take 4 billion years, right, from the origin of life to now. And we have a civilization now, and we've had it, our species have been around, what, a quarter of a million years or something? So it's just now basically. So let's say four billion is on the fortunate side. Let's say that it was double that, or, or triple that on the average. Suddenly, that's the age of the universe, right? (laughs)

Joe Rogan 1:04:40 Right.

Brian Cox 1:04:40 That's a third of the age of the universe it took.

Joe Rogan 1:04:43 Right.

Brian Cox 1:04:43 So how many of those worlds have been stable for 3 or 4 billion years? Th- that's quite a tall order actually. It looks like our solar system might be quite unusual in that respect th- 'cause it, the planet's got to remain stable, in a stable orbit. The star's got to remain stable, at least in our solar system.

Joe Rogan 1:05:03 The large moon helps us.

Brian Cox 1:05:03 Large moon stabilizes. Uh, Jupiter plays a big role and has been-

Joe Rogan 1:05:08 Takes in asteroids.

Brian Cox 1:05:09 Yeah.

Joe Rogan 1:05:10 Sucks them in.

Brian Cox 1:05:10 So, and that, you know, there, there's a thing, there's a theory called the Grand Tack Theory, which is, so it's very hard to explain the evolution of our solar system. So the, 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. And one of the current best theories, and this, I say this 'cause it shows you how lucky we might be, is that Jupiter, they, they tend to form these big gas giants and migrate inwards towards the star. So in almost all the computer simulations, just 'cause you've got this big gas giant orbiting all the dust around the star, they tend to drop inwards. And it looks like Jupiter did that, so it looks like it formed and came in and came in almost to where Mars orbits today, and, and cleared out the region around Mars actually, which is maybe the reason Mars is so small compared to the other, to, to Venus and Earth.

Joe Rogan 1:06:03 Oh.

Brian Cox 1:06:03 But then Saturn was coming in as well. And, uh, in the computer models, the interaction between Jupiter and Saturn stopped Jupiter coming in before it gets to the Earth. And they both get dragged out again (laughs) and so to where they are today.

Joe Rogan 1:06:18 Oh, wow.

Brian Cox 1:06:19 And so that, and that, that seems to be, it's one of the best theories for the evolution of our solar system. So what are the chances? You know, the, the chances of that are so minuscule, like tiny. So y- that, that's the thing I think about these rocky planets, y- in order to get a civilization on them, I think you need, I guess you need quite unusual solar systems, and that would be a guess. And you need quite unusual stability on the planet for, for billions of years. And that's why I think we might be quite lucky.

Joe Rogan 1:06:53 Mm-hmm. And how does Bode's Law work? Bode'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, the size of a neighboring planet.

Brian Cox 1:07:06 I think it wasn't just the, um, the positions of the orbits, I think, I think.

Joe Rogan 1:07:10 Right, where it is.

Brian Cox 1:07:11 Yeah. I know, it's one thing that is true about our solar system is that you, if you get the computer simulations, you can't put more planets in.

Joe Rogan 1:07:19 Mm-hmm.Ah.

Brian Cox 1:07:20 So if you try and fill, put more planets in, they become, it becomes unstable very quickly.

Joe Rogan 1:07:24 So the, the mass of like, if you measure Mars, you can accurately depict where the next planet close to it would be?

Brian Cox 1:07:32 It, it was. I mean, it was, um, that's what was done. Was it 17th century or something? I can't remember.

Joe Rogan 1:07:38 Something like that.

Brian Cox 1:07:38 It was a long ... Yeah, and it was just one of those things where, you know, it's a pattern.

Joe Rogan 1:07:40 Right.

Brian Cox 1:07:41 Um-

Joe Rogan 1:07:41 They were just trying to figure out what the patterns were.

Brian Cox 1:07:42 Yeah, so it's just a pattern, which is, um, you know, not, there's nothing to that really. Um, other than to say that most simulations of the solar system, if there are, uh, if you put other planets in, they tend to get thrown out, th- by gravitational interactions.

Joe Rogan 1:08:00 Hm.

Brian Cox 1:08:00 So there is a sense in which our solar system has got as much stuff in it as it could have. So the planets are nicely spaced. And 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-

Joe Rogan 1:08:16 Hm.

Brian Cox 1:08:16 ... 'cause planets do that, you know. We, we know that planets get thrown out of solar systems by gravitational interactions. So, uh, yeah. So, uh, it, again, it points to the fact that solar systems are not, are not stable over long periods of time. They're not like clockwork things.

Joe Rogan 1:08:34 Hm.

Brian Cox 1:08:34 They're not like, you know, Newtonian clockwork and it just goes on forever. They're not like that. They, they evolve, and planets can shift orbits and change. And one of, we, we know if you look at the surface of the moon, for example, it's covered in craters. And that was 'cause they all seemed to hit about the same time, and it's about 3.8 billion years ago or so. Uh, and that's called the Late Heavy Bombardment. So 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. And that seems to be correlated with Neptune moving outwards-

Joe Rogan 1:09:10 Hm.

Brian Cox 1:09:11 ... 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. So those things happened.

Joe Rogan 1:09:20 And-

Brian Cox 1:09:21 But it didn't happen when life was established on the Earth. Yeah.

Joe Rogan 1:09:25 So it's all extremely old stuff that, that this-

Brian Cox 1:09:28 Yeah.

Joe Rogan 1:09:28 ... these shifting takes place. But, but how long has w- how long has the solar system been in this particularly stable situation it's in now?

Brian Cox 1:09:34 It's, it's since about 3.8 billion years ago.

Joe Rogan 1:09:37 Mm-hmm.

Brian Cox 1:09:38 So if it had been unstable at any point since then, then we likely wouldn't be here.

Joe Rogan 1:09:44 Right. Do 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?

Brian Cox 1:09:52 I, I-

Joe Rogan 1:09:53 Like, this intelligent.

Brian Cox 1:09:54 ... I, I tend to re- I tend to restrict myself to the galaxy.

Joe Rogan 1:09:57 Right.

Brian Cox 1:09:57 So I do-

Joe Rogan 1:09:58 Hm.

Brian Cox 1:09:58 ... think it's possible that, at the moment, there's one civilization in the Milky Way-

Joe Rogan 1:10:03 Wow.

Brian Cox 1:10:03 ... and that's us. And I think that's important, actually. And it goes back to what I was saying at the start about the, uh, 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, the, that has a bearing to me. I mean, imagine that we're the only place where there is intelligence in this galaxy, and how should we behave?

Joe Rogan 1:10:33 Right.

Brian Cox 1:10:33 Should we actually, notwithstanding the fact that we're tiny and fragile things and insignificant physically, should we consider ourselves extremely valuable in that respect? Because there's nowhere else where, uh, you know, there, there, I would go as far as to say there would be nowhere else where meaning exists in the Milky Way.

Joe Rogan 1:10:52 Meaning.

Brian Cox 1:10:52 Because meaning, it's one of those things that scientists don't talk about very much. Although Richard Feynman, one of my great heroes, did talk about it. There's a quote where he says, "What is the meaning of it all?" It's a great essay called The Value of Science. And so, what is self-evidently true is that meaning exists here because it means something to us. So that's kind of a- an obvious statement, you know. Life means something to you and me, and so meaning exists. But I think it is a local and temporary phenomenon. I think it's, it emerges. Meaning emerges from configurations of atoms, which is what we are. We are simply that. We're nothing more than that. We're very, very rare configurations of atoms, I think. And so that means that we are, if you go all the way down that line of logic, we are the only island of meaning in the galaxy, I would say.

Joe Rogan 1:11:48 But meaning only to ourselves.

Brian Cox 1:11:50 Yeah.

Joe Rogan 1:11:51 It means something to us-

Brian Cox 1:11:54 Yeah.

Joe Rogan 1:11:54 ... because we're the only ones who can grasp the concept, and we are finite. We are a finite organism. We have this temporary existence while we're here. And to us, there is meaning.

Brian Cox 1:12:05 Yeah. And that's, I don't know any other way to define it.

Joe Rogan 1:12:07 Right.

Brian Cox 1:12:08 So I'll define it like that.

Joe Rogan 1:12:09 Yes.

Brian Cox 1:12:09 I don't think there's globe- you know. Otherwise, you have to believe there's some kinda global meaning, and that's a God-type thing.

Joe Rogan 1:12:16 Mm-hmm.

Brian Cox 1:12:16 And I don't think that's ... I think it's more wonderful and, and more challenging to us 'cause we have to take responsibility for it to say, "We should operate such that we are it in this galaxy."

Joe Rogan 1:12:29 Mm-hmm.

Brian Cox 1:12:29 There's nothing else. I'm sure, uh, I'm just a f- I'm sure there are other civilizations out there in the universe 'cause there are two trillion galaxies, like, I just can't believe this hasn't happened in other places. The question is, how often does it happen and how widely spaced are the civilizations? And I think they're very widely spaced, and I think there may be one or two per galaxy on the average. I could ... But that, as you said, uh, th- w- what, you said it beautifully, that wha- what else can we think?

Joe Rogan 1:12:58 Right.

Brian Cox 1:12:59 And what, and what else do you want? I 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. It, y- you, you are, you are responsible for that. You, you are that, right? (laughs) That, whatever that is, it exists in you, and it will only exist for a short amount of time. And so-... what, you know, make the best of it, would be my view.

Joe Rogan 1:13:25 It'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.

Brian Cox 1:13:35 I, I would-

Joe Rogan 1:13:36 And this, this thought of it is just so attractive. It's, it's, uh, it's incredible.

Brian Cox 1:13:42 The, there shou- there should be.