Guide to Life, the Universe, and Everything - by Jim Al-Khalili, Part 1

(soft dramatic music) - My name is Jim Al-Khalili. I'm a professional physicist and I've been making films about my passionate interest in science for many years. I never cease to be astonished at the awesome power of science in shedding light on everything in the universe, from the tiniest things in existence to extraordinary objects on a cosmological scale. In this series, I want to show you how science gives us insights into the biggest questions of all. How did the universe come into being?

How did life start on earth, and how does it sustain itself? What is the nature of space and time, the very reality we live in? And how will it all end? (dramatic music) In this episode, we'll look at the first two great pillars of modern physics, Einstein's general theory of relativity, which has radically transformed our understanding of space and time, and quantum mechanics, which reveals the mind-blowingly strange world of the subatomic. And we'll see how the quest to unite the two theories

into a theory of everything has given rise to some extraordinary ideas about the fundamental nature of reality. I want to explore the latest developments and astonishing new theories that continue to shape the way we understand the universe. I hope this series will show you just how amazing our universe is. may never have occurred to you to ask, but once you start looking into this question, the horizons it opens up mind boggling. Okay, so what is space? (static hisses) But does space only exist

when there's stuff in it? Does space only have a meaning when it's enclosed by walls? Ultimately, the question is this. Does space in itself have form? (contemplative music) The properties Of space were first described by the mathematician Euclid over 2,000 years ago in his legendary text "The Elements." In it, he laid down a set of simple logical rules about space in what today we call Euclidean geometry. For Euclid himself and for almost all mathematicians for the next 2,000 years, these rule

s weren't just true mathematically. They were also true statements about physical reality itself. So they thought that two parallel lines would remain parallel forever, that the triangle in real space would always have angles adding up to 180 degrees. But weird as this might sound, it's not actually always true. (soft piano music) Almost 250 years ago in a small town in northern Germany, a mathematician was born. His name was Carl Friedrich Gauss. Gauss tackled many great problems in his career,

but from a young age, he began to speculate that the rules of Euclid may not be as absolute as everyone had assumed. For example, on the surface of a sphere, the angles of a triangle can add up to more than 180 degrees. (discordant music) (static buzzes) Let me explain with this globe. You see, we can see that it's three dimensional because we can stand back and look at it. But what if you were an ant stuck on the surface? How would it know that that surface is curved? So imagine you're the ant

and you start off at the North Pole, and facing south, you move down towards the equator. At the equator, you still face south, and you shuffle sideways along the equator. Then you reach a certain point, and then you start walking backwards so you're still facing the same direction, and head back to the North Pole. Now, look, what's happened here. You've been pointing south all the way round, and yet when you arrive back at your starting point, you're facing in a different direction. Understand

ing this gives us a way of calculating the curvature of the surface without ever leaving it. (soft piano music) This was an amazing insight, but it only applies to curve surfaces, which are two dimensional. It would take a brilliant student of Gauss's, Bernhard Riemann, to develop these ideas in a way that could be applied to the three-dimensional space that surrounds us. Age just 26, Riemann encapsulated his strange new ideas about geometry in a lecture that was to become legendary among mathem

aticians. In June 1854, Riemann delivered his lectures to an enraptured audience. In them, he detailed how he taken Gauss's ideas on curved surfaces and generalized them so that they applied not only to curved two-dimensional surfaces but the curvature of space in any dimension. (audience applauds) Okay, so I'm sure this all sounds rather complicated. What exactly do we mean by curved space in any dimension? So let me try and explain. Here's the thing. Gauss talked about curved two-dimensional s

urfaces. Well, here we have a sheet of paper, and it's two dimensional. So if I curve it, we can visualize and see this curvature but only because it's embedded in three dimensions. Now, what if we curved three dimensions? Presumably, we'd need a fourth dimension. (soft piano music) But how do you get to this four-dimensional space? It's impossible to step outside of our three-dimensional world. Wherever you travel in the universe, no matter how far you go, you're always stuck in three dimension

s. The genius of Riemann was to show that you didn't need to stand in a fourth dimension to tell if space was curved. You could actually do it from the inside. But for Riemann, this would always remain a purely mathematical idea. It would take Albert Einstein to tie these mathematical ideas together and apply bendy, curved, non-Euclidean geometries to the real space that surrounds us. (muffled chatter and laughter) (carnival music) In the general theory of relativity, Einstein took the mathemati

cs of Gauss and Riemann and used it to paint a revolutionary picture of the physical world. He showed that just as Gauss has suspected, the geometry of the space around us isn't always of the regular, flat, Euclidean kind. (upbeat bright calliope music) But if space is bent and warped all around us, surely we must be able observe that this is the case. Well, we do, just not in the way you might expect. This was Einstein's major insight. He showed that it was the ability for space to bend and war

p, for it to be flexible and change its geometry, that gives rise To the force we call gravity. (grunts) All right. Now since Newton's time, gravity was thought to be a force that pulls all objects together. So if I drop this apple, it's as though there's an invisible rubber band that's pulling it down towards the earth. But Einstein's theory of relativity gives us a completely different picture and a totally new perspective. (upbeat bright calliope music) So although gravity appears to be a for

ce, it's nothing more than the curvature of space itself. When an object falls, it's not being pulled by gravity at all. It's just following the simplest path to bent space. (exhales sharply) But the equations of general relativity didn't end there. They revealed that it was the presence of mass that caused the space to curve and distort. The reason we have gravity on earth is because the earth is actually bending the space around it. (soft gentle piano music) And although we don't perceive it l

ike this, Einstein showed us that we live in a four-dimensional universe. The fourth dimension is time. The onward flow of time itself is also warped by gravity, just as much as the other three dimensions of space. (seagulls caw in distance) Gauss, Riemann, and Einstein had between them come up with a description of how the space and time we exist in can be warped. They showed that space and time are not the fixed, unchanging stage on which the actions of the universe are played out. They're act

ually part of the performance. (soft gentle piano music) Einstein's equations were also describing a universe that was expanding. Physicists found it hard to believe at first, but astronomical observations soon told them it was absolutely true. But, and this is the crucial point here, it's not that the galaxies are flying away from each other through space but rather that the fabric of space itself in between the galaxies is expanding. So the universe in its entirety is getting bigger. (undulati

ng whirs echo) (soft gentle piano music) And that led to an inescapable conclusion. If the fabric of space is expanding, then if you wind the clock far enough backwards, there must have been a moment of creation. The universe began with all of its energy squeezed into a singularity, a point of infinite density and gravity. (water splash echoes) From this earliest moment, space expanded rapidly, spreading matter and energy as it grew, to eventually create our vast universe. This event is known as

the Big Bang. If you thought curving space and time is weird, you've heard nothing yet. (coin clinks) Get ready for the impossible world of quantum mechanics. To paraphrase one of the founders of quantum mechanics, everything we call real is made up of things that cannot be themselves regarded as real, (static buzzes) and at stake that everything we thought we knew about the world might turn out to be completely wrong. (explosion echoes) (static hisses) (soft mysterious chiming music) We're goi

ng to start this journey into scientific madness by asking another fundamental question of physics. What is light? Well, you've probably heard of light waves, so perhaps you might imagine that light is a wave. Understandably, that's what many sciences thought, too, in the age before quantum mechanics. It seemed perfectly reasonable. All around us, we see behaving in a perfectly common sense, wavy way. Look at the shadow of my hand. It's fuzzy around the edges. We understand this as the light hit

ting the sides of my hand and bending and smearing out slightly, just like water waves around an obstruction. Perfectly common sense wave-like behavior. Rather like ripples on the surface of water, light was simply ripples of energy spreading through space, and this was as firmly accepted as the fact that the earth was round. But was this always true? Bit by bit, troubling evidence emerged that seem to contradict the received opinion. In the late 19th century, scientists were studying the then n

ewly discovered radio waves and how they were transmitted, and to do that, they were building experimental rigs very similar to this one. Basically, by spinning this disc, they could generate huge voltages that cause sparks to jump across the gap between the two metal spheres. (wheel spins) (sparks snap) But in doing so, they discovered something very unexpected to do with light. They found that by shining a powerful light source on the spheres, they could make the sparks jump across more easily

. This suggested a mysterious an unexplained connection between light and electricity. (soft mysterious music) To understand what was happening, scientists used this. It's called a gold leaf electroscope. It's basically a more sensitive version of the spark gap apparatus. Now, first of all, I have to charge it up. What I'm doing is adding an excess of electrons that are pushing the two gold leaves apart. Now first, I take red light and shine it on the metal surface, and nothing happens. Even if

I increase the brightness of the light, still, the gold leaves aren't effected. Now I'll try this special blue light, rich in ultraviolet. (soft chiming mysterious music) Immediately, the gold leaves collapse. (static hisses) (sparks snap) Light can clearly remove static electric charge from the leaves. It can somehow knock out the electrons I added to them. But why is ultraviolet light so much better at doing this than red light? This new puzzle became known as the photoelectric effect. It was

a big problem for physicists, and it may not surprise you to learn that, once again, it was Albert Einstein who provided the answer. (dramatic music) This is the Archenhold-Sternwarte Observatory in Berlin. Perched on top is a strange, huge iron and steel construction, but it's not a gun. It's actually a telescope. Built in 1896, the telescope was one of the largest of its kind in the world and made the observatory the go-to place to engage and astound the public in new science. Albert Einstein

gave a very famous public lecture here on his theory of relativity, which is, of course, what he's most famous for. But it's not the work that won him the Nobel Prize. (dramatic string music) In 1905, he'd also come up with a new theory to explain the photoelectric effect, and what he suggested was revolutionary and even heretical. (dramatic music with deep choral vocals) He argued that we have to forget all about the idea that light is a wave and think of it instead as a stream of tiny bullet-l

ike particles. The term he used to describe a particle of light was a quantum. (waves crash) I'll try to explain how this helps using a rough analogy. Of course, like all analogies, it's far from perfect, but hopefully it'll give you a sense of the physics to help you understand why thinking of light as a stream of particles solves the mystery of the photoelectric effect. (soft dramatic music) (waves crash) In this analogy, these red balls represent Einstein's light quanta. And those cans over t

here are the electricity held in the metal. Now in the original experiment, they made electricity flow from the surface of the metal by shining light on it. In my analogy, I'm going to try and knock those tin cans over using these red balls. (lively orchestral music) (balls clatter) Absolutely no effect. That's just like red light. (soft dramatic music) According to Einstein, each particle of red light carries very little energy because red light has a low frequency. So even a very bright red li

ght with many red light particles can't dislodge any electrons from the metal plate, just like the red balls. Now I'm gonna use heavier balls like these blue golf balls, and I'm gonna try and knock off the tin cans with these. (balls clatter) (lively orchestral music) (cans clatter) They're like the ultra violet light in the experiment. (cans clatter) Now each individual light particle carries more energy (balls and cans clatter) because ultraviolet light is higher frequency. (balls and cans cla

tter) (soft dramatic music) Just a few of them, like a dim ultraviolet light, are enough to knock the electrons out of the metal plate and collapse the gold leaf. (can clatters) So Einstein's idea that light is made up of tiny particles or quanta is a wonderful explanation of the photoelectric effect. I remember when I first learned about this being blown away by its sheer elegance and simplicity. (static buzzes) (slow dramatic music) Okay, so was Einstein right? Light is made up of tiny bullet-

like particles? Well, yes and no. (up-tempo jazzy ragtime music) Fast forward past the First World War to the Roaring Twenties and another experiment which yet again bamboozled the world of physics. (muffled chatter) It's the birth of modernism, a time of cultural revolution and scientific revolution, too. Most mind boggling of all is an extraordinary experiment which challenged the very basis of reality itself. But weirdly, it was an experiment that wasn't even about light. It was about the par

ticles that make electricity. In the mid 1920s, an experiment was carried out at Bell Laboratories in New Jersey in America, which uncovered something entirely unexpected about electrons. Now at the time, it was accepted without question the electrons were these tiny lumps of matter, small but solid particles like miniature billiard balls. In the experiment, they fired a beam of electrons at a crystal and watched how they scattered. Now that's entirely equivalent to taking a beam of electrons, s

ay, from an electron gun and firing it at a screen with two slits in it so that the electrons pass through the slits and hit another screen at the back. (soft whimsical rhythmic music) What the Bell scientists found shocked the physics world to the core. To understand why, consider a similar experiment with water waves. I've set up a simple experiment. I have a water ripple tank placed on top of an overhead projector. I have a generator producing waves that pass through two narrow gaps. The proj

ector beams the image of the waves onto the back wall. You can see as the waves coming from the left and squeeze through the two gaps, they spread out on the other side and interfere with each other. What this means is that when you get the crest from one wave of meeting the crest from another, they add up to make a higher wave. But when the crest from one meets a trough, they cancel out. This gives rise to these characteristic lines leading to the signature wave pattern. Bands of light and dark

. Whenever you see these lights and dark bands, the signature wave pattern, you know without doubt that you've got wave-like behavior. So guess what they saw in New Jersey? Well, it seemed the firing electrons, tiny solid particles through the two gaps produced exactly the same kind of pattern, bands of light and dark. (brooding contemplative music) First, light, for a long time believed to be a wave, was found to sometimes behave like particles, and now electrons, for a long time believes to be

particles, were behaving like waves. But it was actually stranger than that. The wave pattern wasn't merely some result of the entire beam of electrons. More recently, this experiment has been repeated in labs around the world by firing one electron at a time through the slits onto the screen. (ethereal music) At first, each electron seems to land randomly on the screen. But gradually, a pattern forms, the signature wave pattern. Let me be quite clear about just how weird this is. Remember from

the wave tank experiment where the signature wave pattern only exists because each wave passes through both slits and then its two pieces interfere with each other. But here every individual electron, each single particle is passing alone through the slits before it hits the screen. And yet each single electron is still contributing to the signature wave pattern. Each electron has to be behaving like a wave. (up-tempo jazzy ragtime music) One of the leading exponents of the new science of quant

um mechanics was Niels Bohr. He and his colleagues built a new theory of light and matter, and they just decided to put up with how mind bendingly strange it was. As Niels Bohr himself said, "Anyone who isn't shocked by quantum theory hasn't understood it." So, viewers, I'm going to take our tiny electron and use it to delve deep into the heart of reality. (muffled chatter) And yes, prepare to be shocked because this is the only way to explain what we observe when a single electron travels throu

gh the slits and hits the screen. Quantum mechanics says this. We can't describe what's traveling as a physical object. All we can talk about are the chances of where the electron might be. This wave of chance somehow travels through both slits, producing interference just like the water wave. Then when it hits the screen, what was just the ghostly possibility of an electron mysteriously becomes real. Let me try and capture just how weird this is with an analogy. If I spin this coin, (ethereal m

ysterious music) (coin spins) then all the time it's spinning, it's a blur. I can't tell if it's heads or tails. But if I stop it, I force it to decide, and it's heads. So before it was not heads or tails but a mixture of both, but as soon as I've stopped it, I've forced it to make up its mind. This is what Bohr and his supporters claimed was happening with our electrons. (coin spins) (brooding contemplative music) In a sense, as it spins, the coin is both heads and tails. Similarly, the electro

n's wave of chance passes through both slits, two paths at the same time. Our coin then stops at heads. The ethereal wave of probability hits the screen and only then becomes a particle. The quantum world was unlike anything ever seen before. It's hard to overstate just how crazy this is. Bohr was effectively claiming that one can never know where the electron actually is at all until you measure it. And it's not just that you don't know where the electron is. It's weirdly as though the electron

itself is everywhere at once. (ethereal contemplative music) Bear in mind that electrons are among the commonest and most basic building blocks of reality, and yet here's Bohr saying that only by looking do we actually conjure their position into existence. (static buzzes) It's like there's a curtain between us and the quantum world and behind it, there is no solid reality, just the potential for reality. (coin clatters) Things only become real when we pull back the curtain and look. And this v

iew, ladies and gentlemen, became known as the Copenhagen interpretation. (audience applauds) (soft dramatic music) None of it seemed to make any sense, yet it was proven true in experiment after experiment. So most sciences shrugged aside the philosophical problems and got on with harnessing the incredible power of this new science. It simply didn't matter to them because it worked. They even coined a phrase for it, shut up and calculate. Quantum mechanics led to a profound understanding of sem

iconductors, which helped create the modern electronic age. It produced lasers, revolutionizing communications, breathtaking new medical advances, and breakthroughs in nuclear power. Still to this day, quantum mechanics remains a mystery we simply have to accept. It tells us that on the subatomic scale, there's no such thing as empty space, even in a vacuum. Particles are continually popping into existence and almost immediately canceling themselves out. Space is seething with them, appearing an

d disappearing, and it's thrown up and even craziest sounding phenomenon which seems to defy some of the most sacred laws of physics. It's known as entanglement. Now, entanglement is this special, incredibly close relationship between a pair of quantum particles whose fates are intertwined, for example, if they were created in the same event. (traffic hums) (contemplative music) Let me try and explain this by imagining the two particles are spinning coins. (coins clatter) Imagine these coins are

two electrons created from the same event and then moved apart from each other. Quantum mechanics says that because they're created together, they're entangled, and now many of their properties are forever linked wherever they are. Remember, the Copenhagen interpretation says that until you measure one of the coins, neither of them is heads or tails. In fact, heads and tails don't even exist. And here's where entanglement makes this weird situation even weirder. (coins clatter) When we stop the

first coin and it becomes heads, because the coins are linked through entanglement, the second coin will simultaneously become tails. And here's the crucial thing. I can't predict what the outcome of my measurement will be, only that they would always be opposite. (coins clatter) It was almost too crazy to imagine. It says if the two coins are secretly communicating, communicating instantaneously across space and time, even if the first coin was on earth and the other was on Pluto. Entanglement

may drive the next technological revolution. It underpins quantum computers, machines that could solve problems which are far beyond the reach of the fastest machines that we built today. And yet it remains a mystery because the laws of physics say that nothing can travel instantaneously across space. So how can these particles possibly be entangled with each other? It's something we still don't fully understand. Ever since the two theories were developed around a century ago, scientists have s

uspected that quantum mechanics and Einstein's general theory of relativity were really just two sides of the same coin. Now, both theories describe our reality but on very different scales, quantum mechanics down at the subatomic and general relativity at the cosmic scale. So now the quest is underway to try and unify these two theories to find a so-called theory of everything. (soft dramatic music) In recent years, an astonishing has been gaining ground with many theoretical physicists which m

ay possibly crack that problem. The idea came out of the study of those extraordinary objects in outer space, black holes. When a massive star collapses on itself, it gets smaller and smaller until it heads towards a singularity, a point of infinite density and infinite gravity. It's a weird structure composed of massively warped space and time. It's by studying black holes that physicists have been pursuing one of the biggest questions of all. What is space and time? ("On the Beautiful Blue Dan

ube Op. 314") If you've watched my films before, you probably won't be surprised to see that I've decided to represent the awesome majesty and sheer destructive power of a black hole with a water slide and a rubber duck. My poor little duck is about to fall into the black hole, and while it's not, of course, a literal analogy, if you can imagine the water in the slide represents space and time, I'm hoping my homemade contraption will at least give you an inkling of just how mysterious a black ho

le really is. (footsteps shuffle) (birds chirp) Now imagine that's the black hole over there, the swimming pool, and this is the unfortunate duck that's been caught by its immensely powerful gravitational field and so will be pulled inexorably towards it. The big question is what will happen to the duck as it approaches the black hole. (jaunty precocious instrumental music) Now remember, Einstein realized that space and time aren't fixed or stable. They change according to your perspective and f

actors such as the speed you're traveling and the distortions of the gravity you're in. From the perspective of the duck, things will see normal as it moves towards this inevitable extinction in the jaws of the black hole. At least that's what happens from its perspective. But Einstein's general theory of relativity tells us that from my perspective, something very strange indeed appears to happen. ("The Skaters' Waltz Op. 183") So let's see exactly the same events again but from my perspective.

Because the duck is moving into stronger and stronger gravity, the space around it will distort more and more. The duck will mysteriously seem to get slower and slower and slower from my perspective. Eventually the duck will reach a point of no return. It's called the event horizon, and it's a place where gravity is now so strong that nothing, not even light, can escape. For me, it will seem as if the duck has frozen exactly at the horizon. General relativity says the duck will fall into the bl

ack hole, but I will never know because it's impossible to see beyond the event horizon. And that's one reason why black holes are so mysterious. Now we can't be absolutely certain what would happen to the duck after it falls into the black hole, but it's a pretty safe bet that, at some point, the gravitational stresses inside the black hole are going to rip the duck apart. Now let's take a different duck, in this case, a rather tasteful looking ceramic one. And I ought to use it to demonstrate

a very important idea in physics, but to do that, I'm going to need safety goggles and a hammer. ("Symphony No. 5 in C Minor Op. 67: I. Allegro Con Brio") I'm sorry, but that felt rather good, but I think we can agree that you'd be very hard pressed to put this duck back together again. But it's a very important principle in physics that in theory, we should be able to reconstruct anything, even if it has been smashed to smithereens. So even if the duck has fallen into the black hole and been de

stroyed, the record of it, the information which could put it all back together again, should never be lost from our universe. But this leads us to a major paradox which is still unsolved. So we know that even if the duck falls into the black hole, the information that describes it can't be lost. But, and this was something discovered by Stephen Hawking, black holes have a temperature. They give off radiation, and if you leave them long enough, they'll just evaporate away. But now we have a real

ly big problem. Where has the duck's information gone now? (soft chiming mysterious music) - All right. - [Jim] Some of the world's leading theoretical physicists are wrestling with this very problem. - Hello. - Hi. - How are you? - [Jim] Because it could have enormous consequences for our understanding of reality itself. Physicists such as professor Sean Carroll. - If we want to talk about the black hole information puzzle at all, it's only a puzzle if you know that black holes evaporate becaus

e if if black holes don't evaporate, then you can just say, "The information's not gone. It's in the black hole." (laughs) It's only when you say, "The black hole evaporates and it evaporates into featureless radiation" that the information seems to be lost. So this is a puzzle. This is the real heart of the black hole information loss puzzle. - [Jim] The paradox has led some physicists to an extraordinary suggestion. Although the duck falls into the black hole, what if its information somehow s

tays on the event horizon in the same way as the duck seems to freeze to the outside observer? Professor Marika Taylor has spent years theorizing how this seemingly impossible concept might actually be true. - It turns out that the surface of a black hole really doesn't behave in the way that we would expect it from everyday life. So there are really strong quantum effects around a black hole horizon. And then as you throw something into a black hole, it might be absorbed in this complicated kin

d of quantum computer state. So you can kind of think here as something like in the "Matrix" movie, some really complicated quantum physics going on, the information is kind of trapped there. - It seems that there is very, very good reason to believe that whatever information is inside the black hole can, in the appropriate senses, be thought of as living on the surface of the black hole. (soft whimsical music) - To us conceptualize this extraordinary idea, physicists refer to a technology which

exists right now. It's not an exact analogy, but it helps us understand the basic idea at the heart of it all. This new theory of reality is known as the holographic principle. The reason it's called the holographic principle is because a hologram generates a realistic-looking three-dimensional image. But all the information needed to describe the hologram is contained on a two-dimensional surface. Now the next step in our story is quite extraordinary because some physicists have extended the i

dea of a hologram to explain the entirety of our universe. So it could be that the holographic principle could describe the fundamental nature of everything. (soft pleasant music) - So holography is the idea that the whole of our universe could really be understood in terms of something which lives in two dimensions. That's why people call it holography. - The idea is that somehow what you and I think of as the real tangible three-dimensional world is encoded on a two-dimensional surface. All th

e information there is located on that two-dimensional surface. - [Jim] Professor Juan Maldacena is a world-leading physicist who's developed the idea of the holographic principle. - So the idea is that everything that is happening in our three-dimensional world is really encoded on the two-dimensional boundary, so some region very far away. It's like having a crystal ball, but the ball is very big at the edge of the universe. And yeah, so what's happening in the interior and what's happening in

the boundary are two alternative descriptions of the same reality, and the physical laws, the fundamental physical laws on the boundary are simple, that they create a complex quantum state. - When Maldacena first was giving talks in '97, '98, some of the reactions were, "Look, this has to be crazy, right?" And it was only when he really started to flesh out the calculation, show how it worked mathematically, within six months or so, that the entire community was convinced by it. - After the ini

tial skepticism, thousands of physicists around the world are now working on the holographic principle as a possible explanation for physical reality itself. This is a theory that could bring together the quantum world and the universe as described by general relativity into one all-encompassing theory of everything. Now it's important to say that no one has yet proved that we're all holograms. That's still theoretical speculation at the moment. But the mind-boggling concept taken seriously by a

lot of physicists is that all the information needed to describe our three-dimensional space could be stored in a quantum state on a two-dimensional boundary at the edge of the universe. Now that's quite something to get your head around. - We're still, in some sense, absorbing the paradigm shift, the philosophical consequences of this because it is something very profound to say that really, the three-dimensional reality that we think we live in is deceptive that when we get to the true quantu

m level, that, actually, there's a fundamental two-dimension world. We need to understand this concept more, and we also need to see how we're gonna see signals of this in our astrophysical data, in our cosmological data, in data that we get from particle colliders, such as sun. I think by the end of this century, we'll look back at the beginning of the century and just be astonished about the way our perceptions of physical reality have actually changed. - Well, it's certainly not proven yet, b

ut perhaps in 10 years' time, I'll make another film in which I tell you that yes, it's been proven we are all holograms. Or maybe there's another mind-boggling theory, a whole new way of looking at reality that's waiting round the corner to be discovered. (slow dramatic music) (dramatic music) In the next episode, we'll dig even deeper into the secrets of our existence. We'll see how some deceptively simple laws of physics explain how life can exist and thrive in the universe. We'll learn how t

he breathtaking complexity and exquisite patterns of nature can emerge spontaneously from simple mathematical rules. I'll investigate how the spooky world of quantum mechanics is now helping us understand some of the most important processes in life itself. And we'll ask one of the biggest questions of all. How did life begin? (deep undulating contemplative music)