0:00:05 > 0:00:08Ever since the first humans stood in awe and wonder
0:00:08 > 0:00:12beneath the night sky, we have wanted to know what's out there
0:00:12 > 0:00:14and what is our place in the cosmos.
0:00:16 > 0:00:20For thousands of years, it seemed only religion could provide answers.
0:00:22 > 0:00:25But today, it's science that guides our understanding of the universe.
0:00:27 > 0:00:32The goal is to understand the universe in which we live.
0:00:32 > 0:00:36We want to know why things are the way they are,
0:00:36 > 0:00:41how they work, what everything is. We want to understand.
0:00:41 > 0:00:46Was there a beginning? Did time continue before the Big Bang?
0:00:46 > 0:00:50This is the deepest problem in cosmology.
0:00:52 > 0:00:55Over the last 50 years, Horizon and the BBC have been
0:00:55 > 0:01:00following science's pursuit of the biggest questions humanity can ask.
0:01:00 > 0:01:03Where did the universe come from? How did we get here?
0:01:03 > 0:01:05Are we alone?
0:01:05 > 0:01:08This is the story of our final frontier -
0:01:08 > 0:01:11the search for a complete understanding of the universe.
0:01:31 > 0:01:34JFK: Man in his quest for knowledge and progress
0:01:34 > 0:01:36is determined and cannot be deterred.
0:01:36 > 0:01:39The exploration of space will go ahead.
0:01:41 > 0:01:43We choose to go to the moon.
0:01:43 > 0:01:49We choose to go to the moon in this decade and do the other things,
0:01:49 > 0:01:51not because they are easy, but because they are hard.
0:01:53 > 0:01:57When President John F Kennedy made that speech in 1962,
0:01:57 > 0:01:59it was at the moment when human
0:01:59 > 0:02:03exploration of space changed from science fiction into reality.
0:02:03 > 0:02:08Hello, Apollo 11. Houston. We'd like you press on to star 44. Over.
0:02:08 > 0:02:12Up until this point, the idea of leaving our planet,
0:02:12 > 0:02:16and travelling into the cosmos seemed fantastical.
0:02:18 > 0:02:22But within a decade, men had stood on the surface of the moon.
0:02:22 > 0:02:24One small step for man...
0:02:24 > 0:02:27It was a technological triumph...
0:02:29 > 0:02:32..and perhaps the greatest voyage of discovery that we humans
0:02:32 > 0:02:34have ever undertaken.
0:02:49 > 0:02:53For thousands of years, explorers have set sail to discover new lands
0:02:53 > 0:02:56and find what lies beyond the horizon.
0:03:00 > 0:03:03But now, the nature of exploration is changing.
0:03:03 > 0:03:08Today, we've mapped, we've catalogued, we've photographed
0:03:08 > 0:03:12virtually every corner of the globe. We've even gone into space.
0:03:12 > 0:03:16The human desire to explore is as strong as it has ever been.
0:03:16 > 0:03:19The difference is, today, we don't need to physically
0:03:19 > 0:03:21set sail into the unknown to learn new things.
0:03:21 > 0:03:24Most of what we understand about the universe didn't come from our
0:03:24 > 0:03:28space missions. Instead, it came from our clever instruments,
0:03:28 > 0:03:32the great minds and extraordinary imaginations
0:03:32 > 0:03:33of the people right here on Earth.
0:03:38 > 0:03:41Back in the 17th century, one of the greatest breakthroughs in
0:03:41 > 0:03:45the history of science was made in this apple orchard in Lincolnshire.
0:03:48 > 0:03:51It would reveal the fundamental force that
0:03:51 > 0:03:55keeps our feet on the ground and binds the entire universe together.
0:03:57 > 0:04:01The idea sprung from the imagination of Britain's best-known scientist.
0:04:02 > 0:04:05No, it wasn't Brian Cox, it was Isaac Newton.
0:04:07 > 0:04:12The story goes that it was in this orchard that Newton was sat
0:04:12 > 0:04:16thinking about the universe and an apple fell on Newton's head
0:04:16 > 0:04:20and got him thinking about what it is that makes the apple fall.
0:04:20 > 0:04:23What force pulls the apple towards the ground?
0:04:26 > 0:04:30Newton suggested that the apple falls because of a force of attraction
0:04:30 > 0:04:34that naturally exists between the apple and the Earth.
0:04:36 > 0:04:39It's this force that we know as gravity.
0:04:41 > 0:04:45But Newton's real genius was not to just stop with the apple,
0:04:45 > 0:04:48but to ask the question, "Is the same force that causes the apple
0:04:48 > 0:04:52"to fall here on Earth also responsible for the movement
0:04:52 > 0:04:54"of much bigger things out there in the cosmos?"
0:04:59 > 0:05:03Newton believed that gravity is a force that acts throughout
0:05:03 > 0:05:05the entire universe.
0:05:07 > 0:05:12In 1686, he finally managed to break it down into one single
0:05:12 > 0:05:15mathematical equation.
0:05:16 > 0:05:20Newton's understanding of gravity is actually incredibly simple -
0:05:20 > 0:05:24the force between two objects depends on only two things:
0:05:24 > 0:05:27the mass of the objects and the distance they are apart.
0:05:27 > 0:05:31So the more massive the objects, the stronger the force, and the further
0:05:31 > 0:05:34the objects are apart, the weaker the force.
0:05:36 > 0:05:41With one beautiful bit of maths, Newton had figured out gravity.
0:05:42 > 0:05:43But not just here on Earth.
0:05:46 > 0:05:49The Moon seemed to orbit the Earth exactly as he predicted...
0:05:52 > 0:05:54..as did the planets orbiting around the Sun.
0:05:57 > 0:06:01Newton believed we live in a universe in which, ultimately,
0:06:01 > 0:06:03the movement of everything can be predicted.
0:06:08 > 0:06:12Newton's Law of Gravity was a huge leap forward
0:06:12 > 0:06:14in our understanding of the universe.
0:06:14 > 0:06:19It told us why the sun moves across the sky and why the Moon waxes
0:06:19 > 0:06:20and wanes each month.
0:06:23 > 0:06:27Gravity locks the Moon into orbit around the Earth, and the Earth and
0:06:27 > 0:06:31all the planets into orbit around the sun. They move like clockwork.
0:06:34 > 0:06:38And those movements can be predicted with such astonishing accuracy
0:06:38 > 0:06:41that, three centuries after the falling apple,
0:06:41 > 0:06:43we were able to use Newton's equations to launch
0:06:43 > 0:06:47a rocket from Earth and land it safely on the Moon.
0:06:57 > 0:07:01Figuring out one of fundamental laws of the universe from an orchard
0:07:01 > 0:07:05in Lincolnshire was a pretty impressive bit of thinking. In fact,
0:07:05 > 0:07:09nothing quite that extraordinary was to come along for another 300 years.
0:07:09 > 0:07:12But when it did, it was mind blowing.
0:07:22 > 0:07:24For Albert Einstein,
0:07:24 > 0:07:28Newton's brilliant description of gravity wasn't quite enough.
0:07:28 > 0:07:34Einstein wanted to know what caused gravity in the first place.
0:07:34 > 0:07:36And in one gigantic leap of imagination,
0:07:36 > 0:07:39he managed to come up with the answer.
0:07:41 > 0:07:45Einstein called his theory General Relativity,
0:07:45 > 0:07:48but the concepts were so bizarre, scientists ever since
0:07:48 > 0:07:51have needed just as much imagination to explain them.
0:07:52 > 0:07:58The Theory of Relativity is infamous for its difficulty.
0:07:59 > 0:08:04I want to show that there's nothing peculiarly difficult about it.
0:08:05 > 0:08:08Here's a little piece of the universe
0:08:08 > 0:08:11and each of these stars represents a galaxy.
0:08:11 > 0:08:13If I just stretch the rubber band...
0:08:13 > 0:08:15Let me illustrate this with an example here.
0:08:15 > 0:08:17Let's imagine this piece of jelly is the space.
0:08:17 > 0:08:20Then the presence of matter is to distort the space.
0:08:20 > 0:08:22The sun or the Earth bends space-time.
0:08:22 > 0:08:25In bent space-time, you don't move in a straight line any more.
0:08:26 > 0:08:30According to Einstein, space isn't simply an empty void.
0:08:30 > 0:08:33It's more like a fabric woven from both space and time.
0:08:35 > 0:08:38Objects like stars bend the space time around them.
0:08:38 > 0:08:41Certainly, Einstein's Theory of Relativity
0:08:41 > 0:08:44does lead us down some very strange and unfamiliar paths.
0:08:46 > 0:08:51Any object that passes through that warped space-time will move
0:08:51 > 0:08:53as if being pulled by a force
0:08:53 > 0:08:55and that's what we experience as gravity.
0:08:57 > 0:09:03Relativity is perfectly intelligible to anybody who is willing to think.
0:09:05 > 0:09:09General relativity is probably one of the greatest feats
0:09:09 > 0:09:11of human thinking ever accomplished.
0:09:16 > 0:09:18And bizarre as the theory may sound,
0:09:18 > 0:09:21experimental evidence has proved that Einstein was right.
0:09:23 > 0:09:27Gravity really is a distortion of space and time.
0:09:29 > 0:09:30BANJO MUSIC
0:09:36 > 0:09:37Armed with Newton's gravity
0:09:37 > 0:09:41and Einstein's Theory of Relativity, scientists could predict
0:09:41 > 0:09:45and explain the movements of everything in the cosmos,
0:09:45 > 0:09:49from an apple falling to the ground to the orbits of the planets
0:09:49 > 0:09:50and the stars.
0:09:51 > 0:09:56Einstein and Newton completely revolutionised our understanding
0:09:56 > 0:09:59of the universe and they revealed much of the inner workings
0:09:59 > 0:10:05of the cosmos using almost entirely the power of abstract thought.
0:10:05 > 0:10:08Now, great minds like those don't come along very often
0:10:08 > 0:10:09and, luckily, they don't need to,
0:10:09 > 0:10:13because human beings have another great skill that's just as useful
0:10:13 > 0:10:17when it comes to unravelling the secrets of the universe.
0:10:17 > 0:10:19We're very good at building things.
0:10:22 > 0:10:25In the early 1900s, astronomers set out
0:10:25 > 0:10:29to build the most powerful telescope the world had ever seen.
0:10:34 > 0:10:38A 4,000 kilogram slab of glass was ground and polished for five years,
0:10:38 > 0:10:42to produce a gigantic mirror that was installed into the brand-new
0:10:42 > 0:10:46Hooker telescope, here the Mount Wilson Observatory in California.
0:10:48 > 0:10:52The mighty telescope could see, not just the stars in our own sky,
0:10:52 > 0:10:55but the stars in other galaxies,
0:10:55 > 0:10:58trillions and trillions of miles away.
0:10:58 > 0:11:01And it was these distant galaxies that would lead astronomer
0:11:01 > 0:11:06Edwin Hubble to discover the origin of the universe itself.
0:11:14 > 0:11:15Up until this point,
0:11:15 > 0:11:19people had thought that the universe was eternal and unchanging.
0:11:19 > 0:11:23After all, the stars had been twinkling away in the night sky
0:11:23 > 0:11:25ever since anyone could remember.
0:11:28 > 0:11:32But with the new, super-powerful Hooker telescope,
0:11:32 > 0:11:34Hubble saw something remarkable...
0:11:36 > 0:11:38The universe was on the move.
0:11:39 > 0:11:42The distant galaxies were hurtling through space.
0:11:44 > 0:11:47And Hubble could even work out which direction they were moving in,
0:11:47 > 0:11:51thanks to a handy bit of physics, known as the Doppler Shift.
0:11:52 > 0:11:54STEAM ENGINE WHISTLES
0:11:54 > 0:11:58In 1978, Horizon enlisted the help of a steam train, and no fewer than
0:11:58 > 0:12:03six professional trumpeters, to show us how the Doppler Shift works.
0:12:03 > 0:12:07This baroque experiment was actually first tried by a Dutch physicist
0:12:07 > 0:12:11in the flatlands of Holland - steam engine, uniformed bandsmen and all.
0:12:22 > 0:12:24Yes. Half a semitone?
0:12:25 > 0:12:27- Do you think?- Yes.- What speed do you think he was doing?
0:12:27 > 0:12:30I think about 40 kilometres.
0:12:31 > 0:12:33The expert trumpeters on the train
0:12:33 > 0:12:35certainly held their pitch constant, at a middle C,
0:12:35 > 0:12:38but listeners on the ground heard the tone change
0:12:38 > 0:12:40as the locomotive puffed by.
0:12:41 > 0:12:44It was the physicist Christian Doppler, of Prague, who first
0:12:44 > 0:12:48pointed out, 150 years ago, that such a change of pitch would be expected
0:12:48 > 0:12:52whenever a steady source of waves moved with respect to an observer.
0:12:52 > 0:12:55Today, we call it the Doppler Shift.
0:12:57 > 0:13:01Approaching - higher pitch, shorter waves.
0:13:01 > 0:13:05Receding - lower pitch, longer waves.
0:13:06 > 0:13:10By listening for changes in the pitch of the note, it's possible to
0:13:10 > 0:13:14work out if the source of the sound is moving towards or away from you.
0:13:17 > 0:13:20And the same principle applies to light.
0:13:23 > 0:13:26Using the powerful Hooker telescope,
0:13:26 > 0:13:29Hubble measured the wavelengths of light coming from distant galaxies.
0:13:34 > 0:13:38He discovered they were all hurtling away from each other
0:13:38 > 0:13:42and that could only mean one thing - the universe is expanding.
0:13:46 > 0:13:50If the universe is expanding, that means yesterday, it must have
0:13:50 > 0:13:53been smaller and the day before that, smaller still.
0:13:53 > 0:13:55And if you keep winding the clock back, it gets smaller
0:13:55 > 0:13:58and smaller and smaller until, at some point, the whole thing
0:13:58 > 0:14:02must have been all squashed together in a single tiny space.
0:14:02 > 0:14:07Hubble had discovered that, far from being eternal and unchanging,
0:14:07 > 0:14:09the universe had a beginning.
0:14:15 > 0:14:17Scientists called it The Big Bang -
0:14:17 > 0:14:21a single moment of creation, in which everything in the universe
0:14:21 > 0:14:23burst into existence.
0:14:28 > 0:14:32From a hilltop in Los Angeles, Hubble had discovered
0:14:32 > 0:14:34the origin of the universe.
0:14:35 > 0:14:38But he knew he could go one step further than that,
0:14:38 > 0:14:42because if he could work out the speed at which the galaxies
0:14:42 > 0:14:46were moving, he would know how long the cosmos had taken to grow
0:14:46 > 0:14:47to its present size.
0:14:47 > 0:14:50He could calculate the age of the universe.
0:15:00 > 0:15:05But even with the most powerful telescope in the world at the time,
0:15:05 > 0:15:08Hubble couldn't see distant galaxies in very much detail.
0:15:08 > 0:15:11He could tell that they were moving,
0:15:11 > 0:15:15but it was impossible to calculate their speed with any accuracy.
0:15:15 > 0:15:19The problem was that no matter how sensitive the telescope,
0:15:19 > 0:15:21the Earth's atmosphere distorts the light
0:15:21 > 0:15:24coming from distant galaxies,
0:15:24 > 0:15:26making it impossible to see them with any clarity.
0:15:28 > 0:15:33In 1953, Edwin Hubble died without ever managing to calculate
0:15:33 > 0:15:35the true age of the universe.
0:15:43 > 0:15:46But 25 years later, a new building project began.
0:15:46 > 0:15:51This time, astronomers set out to build a telescope that would be free
0:15:51 > 0:15:54from the distorting effects of Earth's atmosphere.
0:15:54 > 0:15:57Because this telescope would be launched into space.
0:15:59 > 0:16:03It took 13 years, one and half billion dollars,
0:16:03 > 0:16:06and a mirror so perfectly curved it could capture
0:16:06 > 0:16:10light from distant galaxies in pin-sharp detail.
0:16:10 > 0:16:13Its mission was to discover the age of the universe.
0:16:15 > 0:16:17It was named the Hubble Space Telescope in honour
0:16:17 > 0:16:19of Edwin Hubble's groundbreaking work.
0:16:19 > 0:16:25But it very nearly tarnished the reputation of the whole of science.
0:16:35 > 0:16:36And lift off!
0:16:36 > 0:16:40The space shuttle Discovery with the Hubble Space Telescope.
0:16:40 > 0:16:42A window on the universe.
0:16:47 > 0:16:50There are smiles galore down here.
0:16:50 > 0:16:52It's quite a sight.
0:16:52 > 0:16:54Great work up there, you guys.
0:16:59 > 0:17:01The moment everyone was waiting for had arrived.
0:17:04 > 0:17:08Hubble was ready to transmit its first pictures back to Earth.
0:17:14 > 0:17:16But something was wrong.
0:17:20 > 0:17:23What we had expected to see in those first images
0:17:23 > 0:17:25were very, very sharp points of light.
0:17:25 > 0:17:28What we actually saw were kind of big blurry things.
0:17:31 > 0:17:35In fact things that at first glance didn't look a lot sharper
0:17:35 > 0:17:37than what we could see from the ground.
0:17:38 > 0:17:41And we looked at them and we thought, "Hmm."
0:17:45 > 0:17:48The Hubble had a serious problem.
0:17:48 > 0:17:51The most perfect mirror in the world...
0:17:51 > 0:17:52was the wrong shape.
0:17:54 > 0:17:57It was slightly too flat,
0:17:57 > 0:17:59which meant that the light reflected from its edge,
0:17:59 > 0:18:03and light from its centre, were focused in different places.
0:18:04 > 0:18:07It could not produce a sharp image.
0:18:07 > 0:18:10And there was nothing anyone could do about it.
0:18:18 > 0:18:22Remarkably the original equipment used to test the mirror was
0:18:22 > 0:18:24still in position.
0:18:24 > 0:18:27And it was here they discovered that unknown
0:18:27 > 0:18:31to anybody one tiny accident had crippled the telescope.
0:18:32 > 0:18:36A fleck of black paint just two millimetres wide
0:18:36 > 0:18:38had at some stage been
0:18:38 > 0:18:41chipped off the cap of one of the measuring rods that had been
0:18:41 > 0:18:42used to test the mirror's shape.
0:18:45 > 0:18:47This exposed a chink of metal.
0:18:49 > 0:18:52Light hitting this chink distorted the measurements,
0:18:52 > 0:18:54causing the fatal error.
0:18:55 > 0:18:58The mirror was only minutely misshapen -
0:18:58 > 0:19:01just a 50th of a width of a human hair.
0:19:02 > 0:19:05But it was enough to put the mission's goals out of reach.
0:19:07 > 0:19:10The Hubble had to be saved at all costs.
0:19:11 > 0:19:16Which we listed as mechanical correction or deformation.
0:19:17 > 0:19:20We put everything on the table,
0:19:20 > 0:19:24even the craziest idea to see what we could do to fix the problem.
0:19:24 > 0:19:27This is replacement of the secondary,
0:19:27 > 0:19:29just as a straight correction.
0:19:30 > 0:19:32And they range from going
0:19:32 > 0:19:34up in the shuttle taking the space craft,
0:19:34 > 0:19:36bringing it back to Earth and replacing the primary mirror.
0:19:36 > 0:19:41To send astronauts up and actually inside the tube
0:19:41 > 0:19:44of the telescope to do something to the optics.
0:19:47 > 0:19:49Among the proposals was the ingenious solution.
0:19:49 > 0:19:54An instrument that would match the error in the mirror in reverse
0:19:54 > 0:19:56and cancel it out.
0:20:00 > 0:20:03Plans for an ambitious repair mission began to take shape.
0:20:14 > 0:20:18The astronaut team undertook the most punishing training
0:20:18 > 0:20:21schedule since Apollo to make ready for this boldest of missions.
0:20:24 > 0:20:30Five, four, three, two, one...
0:20:31 > 0:20:32..and we have lift off!
0:20:32 > 0:20:35Lift off of the space shuttle Endeavour on an ambitious
0:20:35 > 0:20:37mission to service the Hubble Space Telescope.
0:20:41 > 0:20:46In December 1993 the impossible mission was launched.
0:20:51 > 0:20:54Hello, Houston, we are ready. Let's go fix this thing.
0:20:56 > 0:20:58The astronauts got to work.
0:20:59 > 0:21:00They knew that the tiniest mistake
0:21:00 > 0:21:03could be catastrophic for the mission.
0:21:10 > 0:21:14First came the delicate task of putting in the new camera.
0:21:16 > 0:21:18It goes in with incredible precision.
0:21:18 > 0:21:20What we were worried about was
0:21:20 > 0:21:22any astronaut could just kind of bump into it,
0:21:22 > 0:21:24and that would be the end of our mission.
0:21:27 > 0:21:31The astronauts eased the new camera into place.
0:21:31 > 0:21:32My side looks good.
0:21:32 > 0:21:37That's beautiful. Looks like it's in there.
0:21:47 > 0:21:51Two weeks later, it was time to put the repairs to the test.
0:21:53 > 0:21:55CHEERING
0:21:55 > 0:21:59- Right there!- Ooh!
0:21:59 > 0:22:02- Wait, wait, wait.- Yeah. Yeah.
0:22:02 > 0:22:04Those are actually stars!
0:22:11 > 0:22:14Orbiting 350 miles above our planet,
0:22:14 > 0:22:19the telescope could see distant galaxies in breathtaking clarity,
0:22:19 > 0:22:22and measure the speed at which they were moving
0:22:22 > 0:22:24with unprecedented accuracy.
0:22:24 > 0:22:27The Hubble Space Telescope was finally able to finish
0:22:27 > 0:22:29the work that Edwin Hubble had started.
0:22:29 > 0:22:33It could measure the age of the universe.
0:22:33 > 0:22:37The answer was 13.7 billion years.
0:22:47 > 0:22:50The Hubble Space Telescope went on to produce the most
0:22:50 > 0:22:54magnificent images of the universe the world had ever seen.
0:23:01 > 0:23:05They showed that space isn't just an endless blanket of stars -
0:23:05 > 0:23:09it's populated by a bewildering variety of celestial phenomenon.
0:23:11 > 0:23:15There are colossal furnaces where new stars are forged.
0:23:15 > 0:23:18And violent explosions where others have died.
0:23:20 > 0:23:25There are ancient, primordial galaxies in the furthest reaches
0:23:25 > 0:23:29of space, and newer ones stretching out in majestic, glittering spirals.
0:23:29 > 0:23:31Hubble would have been proud.
0:23:40 > 0:23:44The construction and launch of the Hubble Space telescope was
0:23:44 > 0:23:49one of the most ambitious engineering projects ever attempted.
0:23:49 > 0:23:50But if it wasn't for the skill
0:23:50 > 0:23:52and the determination of the engineers,
0:23:52 > 0:23:55then it could have become one of science's greatest failures.
0:23:55 > 0:23:59It's that persistence and determination to overcome problems
0:23:59 > 0:24:03that has driven our quest to understand the universe.
0:24:03 > 0:24:07And nowhere have we needed it more than to find the answer
0:24:07 > 0:24:11to perhaps our most profound question - are we alone?
0:24:19 > 0:24:22Science fiction fans aren't the only ones
0:24:22 > 0:24:24who believe in extraterrestrials.
0:24:24 > 0:24:25Hello!
0:24:28 > 0:24:31Is there anyone out there?
0:24:34 > 0:24:37Plenty of scientists believe in them too.
0:24:37 > 0:24:41In fact, science's determination to find alien life
0:24:41 > 0:24:43borders on obsession.
0:24:44 > 0:24:48They've scoured the skies, sent messages out into space
0:24:48 > 0:24:53and spent years listening intently for the faintest sign of ET.
0:24:53 > 0:24:56So far, they've found nothing.
0:25:04 > 0:25:08But there is one place they have been searching more than any other.
0:25:08 > 0:25:13Generations of scientists have dreamed of finding life there.
0:25:13 > 0:25:16It's our nearest planetary neighbour - Mars.
0:25:16 > 0:25:20Something is happening to the children of Mars.
0:25:22 > 0:25:25As leader of the Martians you must do something about it.
0:25:25 > 0:25:27I know. But what?
0:25:36 > 0:25:40In the late 19th century, American astronomer Percival Lowell was
0:25:40 > 0:25:42so convinced that life existed on Mars,
0:25:42 > 0:25:45he thought the markings he could see
0:25:45 > 0:25:47through his telescope must be canals,
0:25:47 > 0:25:49built by a Martian civilisation.
0:25:52 > 0:25:55Up until the 1970s, it was thought that dark patches
0:25:55 > 0:25:59on the surface of the red planet could be extraterrestrial forests.
0:26:01 > 0:26:03We've just had some amazing photographs sent back
0:26:03 > 0:26:05by the American probe to Mars - Mariner 6.
0:26:05 > 0:26:08Just look at that!
0:26:08 > 0:26:11You can see some of the dark areas, which may be vegetation...
0:26:13 > 0:26:17Of course, those early observations were just tricks of the eye.
0:26:17 > 0:26:20But the hope of finding Martians never faded.
0:26:20 > 0:26:23And in 1996,
0:26:23 > 0:26:27the first strong evidence of life on Mars was announced.
0:26:27 > 0:26:32If this discovery is confirmed, it will surely be one of the most
0:26:32 > 0:26:36stunning insights into our universe that science has ever uncovered.
0:26:39 > 0:26:43Researchers working in Antarctica had found a meteorite
0:26:43 > 0:26:44lying in the snow.
0:26:49 > 0:26:52A battery of tests showed that this was no ordinary meteorite -
0:26:52 > 0:26:54it had come from Mars.
0:27:01 > 0:27:05Closer analysis revealed something extraordinary.
0:27:05 > 0:27:08The Martian rock contained large quantities of organic carbonates...
0:27:10 > 0:27:14..a compound that is usually associated with living things.
0:27:14 > 0:27:16This is just going to knock
0:27:16 > 0:27:18the socks off of people when they see this.
0:27:18 > 0:27:23Samples were sent to NASA, where astrobiologist Everett Gibson
0:27:23 > 0:27:24set out to establish
0:27:24 > 0:27:28if this meteorite contained evidence of alien life.
0:27:30 > 0:27:33Everett Gibson took the meteorite to the head of NASA's electron
0:27:33 > 0:27:35microscope lab, Dave McKay.
0:27:37 > 0:27:41As we zoom in on this cave area here,
0:27:41 > 0:27:43we see some interesting features.
0:27:44 > 0:27:48One evening, after David had spent many long hours on the microscope,
0:27:48 > 0:27:51we were moving around and we came across a region
0:27:51 > 0:27:53that appeared to be a little different
0:27:53 > 0:27:55to what we had normally seen.
0:27:55 > 0:28:00And we kept scanning in and scanning in at higher magnification,
0:28:00 > 0:28:02and we saw something that caught our eye.
0:28:08 > 0:28:11And we said, "What is that?"
0:28:11 > 0:28:16We found this structure. It had 10-12 segments in it,
0:28:16 > 0:28:21and appeared to have a head, and appeared to have a tail.
0:28:21 > 0:28:24And we looked at each other
0:28:24 > 0:28:28and kind of looked with this look that said, "This can't be."
0:28:28 > 0:28:32And the significance of the structure got to both of us.
0:28:32 > 0:28:34That night I had difficulty sleeping.
0:28:35 > 0:28:40I was saying, "Could we have a microfossil here from Mars?"
0:28:42 > 0:28:44Later this month, scientists are
0:28:44 > 0:28:49expected to announce remarkable new findings about life on Mars.
0:28:51 > 0:28:57We are right on the edge of a potential unbelievable discovery
0:28:57 > 0:28:59that's going to rock our world if it's true.
0:29:02 > 0:29:05Sure enough, the press had a field day.
0:29:07 > 0:29:11They are the remains of Martian life.
0:29:13 > 0:29:14But there's a problem.
0:29:14 > 0:29:18Some microbiologists think that what NASA are seeing are might not
0:29:18 > 0:29:20be bugs but blobs -
0:29:20 > 0:29:22artefacts created
0:29:22 > 0:29:26when the sample is coated with gold for use in the electron microscope.
0:29:27 > 0:29:28Is the fact that things
0:29:28 > 0:29:31are consistent with the presence of life
0:29:31 > 0:29:32enough to convince you
0:29:32 > 0:29:36that you're making one of the most sensational claims ever made.
0:29:36 > 0:29:38And I would say no.
0:29:38 > 0:29:42What you need is evidence that requires life to explain it.
0:29:45 > 0:29:47Nealson's team have been looking at rocks with a new
0:29:47 > 0:29:49kind of electron microscope.
0:29:51 > 0:29:53This one can work without the gold coating.
0:29:55 > 0:29:58To my way of thinking, it's very impressive how different
0:29:58 > 0:30:02the samples are when they're coated with gold or not coated.
0:30:03 > 0:30:06His uncoated rocks look jagged and crystalline
0:30:06 > 0:30:07at high magnification.
0:30:09 > 0:30:13But add the gold coating and tiny blobs appear,
0:30:13 > 0:30:17which are about the same size as the famous Martian worm.
0:30:17 > 0:30:20The edges now can be rounded off with the gold
0:30:20 > 0:30:23and even an expert could be fooled.
0:30:23 > 0:30:27You look at it and you say, "Wow, that could be life."
0:30:29 > 0:30:32So this might just be rock fragments,
0:30:32 > 0:30:35made to look like a worm by a thin coating of gold.
0:30:41 > 0:30:45Almost 20 years later, the controversy still goes on.
0:30:59 > 0:31:03So far, we've found no signs of intelligent life on Mars
0:31:03 > 0:31:06and no hard evidence of microbes either.
0:31:06 > 0:31:09But all hope is not lost.
0:31:10 > 0:31:13Even if Mars is barren and lifeless today,
0:31:13 > 0:31:16it might still have been a home to life in the past.
0:31:17 > 0:31:19Because for a planet to support life,
0:31:19 > 0:31:22there is one vital ingredient it must have.
0:31:23 > 0:31:27One special substance that it's thought any alien,
0:31:27 > 0:31:28anywhere will need...
0:31:30 > 0:31:32..water.
0:31:32 > 0:31:35Life involves complex chemical reactions -
0:31:35 > 0:31:39and as far as we know, complex chemistry needs liquid water.
0:31:41 > 0:31:43On Earth, wherever there is water, there is life.
0:31:54 > 0:31:56So if Mars once had liquid water,
0:31:56 > 0:32:01then it dramatically increases the chance that it once had life too.
0:32:14 > 0:32:16An armada of spacecraft
0:32:16 > 0:32:20and six robotic rovers have been sent probe the red planet.
0:32:24 > 0:32:28They've found no sign of water on the surface today.
0:32:31 > 0:32:36But there is plenty of evidence that things were different in the past.
0:32:38 > 0:32:41Did a river once flow through this valley?
0:32:41 > 0:32:43Was this once a lake?
0:32:46 > 0:32:50Perhaps, billions of years ago, Mars had oceans, clouds and rain,
0:32:50 > 0:32:52just like the Earth.
0:32:53 > 0:32:55It's an intoxicating thought.
0:33:05 > 0:33:09Last year, NASA sent one more rover - Curiosity -
0:33:09 > 0:33:12to the surface of the red planet.
0:33:12 > 0:33:15It's the most sophisticated ever built.
0:33:15 > 0:33:17Just a few weeks ago, it landed.
0:33:19 > 0:33:22Its mission is to discover once and for all
0:33:22 > 0:33:25if Mars ever had the conditions to support life.
0:33:27 > 0:33:29Here's hoping.
0:33:42 > 0:33:44Finding any kind of life on Mars,
0:33:44 > 0:33:47even if it's the fossilised remains of tiny bacteria,
0:33:47 > 0:33:52would mean that the Earth is not unique in that respect.
0:33:52 > 0:33:57But the real goal it to try and find complex intelligent life.
0:33:57 > 0:34:00Now we're probably not going to find it within our solar system,
0:34:00 > 0:34:03but there's a lot of other solar systems out there,
0:34:03 > 0:34:08and perhaps orbiting another star in another part of the galaxy
0:34:08 > 0:34:09is a planet just like Earth.
0:34:09 > 0:34:12The problem that we've got is finding it.
0:34:17 > 0:34:22With 200 billion stars in our own galaxy alone, astronomers had
0:34:22 > 0:34:25suspected for centuries that there must be other planets out there.
0:34:25 > 0:34:28But they'd never managed to see one.
0:34:30 > 0:34:32I have little doubt that at this very moment,
0:34:32 > 0:34:35on some alien far-off planet.
0:34:35 > 0:34:36There's a broadcaster
0:34:36 > 0:34:40addressing an audience saying exactly what I am saying to you.
0:34:40 > 0:34:43And on his TV screen he maybe showing a star field.
0:34:44 > 0:34:45But suppose we could
0:34:45 > 0:34:49look at that scene from a planet going around the nearest star.
0:34:49 > 0:34:51The overall view would be the same,
0:34:51 > 0:34:56but there would be an extra point of light representing our own sun.
0:34:56 > 0:34:59And if the sun appears only as a point, what chance
0:34:59 > 0:35:02would our hypothetical astronomer have of seeing the Earth?
0:35:02 > 0:35:04Obviously none at all.
0:35:04 > 0:35:07In fact, from the Earth we similarly cannot see the planets of
0:35:07 > 0:35:10other stars. We can only infer that they exist.
0:35:10 > 0:35:12But I'm quite sure that they do.
0:35:15 > 0:35:19Spotting a planet in orbit around a distant star is like trying
0:35:19 > 0:35:22to spot a grain of sand in the glare of a floodlight,
0:35:22 > 0:35:25from a hundred miles away.
0:35:25 > 0:35:28So not surprisingly, astronomers struggled to find any
0:35:28 > 0:35:30planets at all, let alone one that looked like ours.
0:35:31 > 0:35:35The search for another Earth was stuck in the starting blocks.
0:35:36 > 0:35:40But, in the 1950s, a Russian astronomer named Otto Struve
0:35:40 > 0:35:44had come up with an ingenious idea.
0:35:44 > 0:35:47He suggested a way to spot planets by looking at stars.
0:35:50 > 0:35:54Gravity holds planets in orbit around their stars.
0:35:54 > 0:35:59The star pulls on the planet, but the planet also pulls
0:35:59 > 0:36:03back on the star, making the star move with the tiniest of wobbles.
0:36:11 > 0:36:14Struve argued that this wobble should be
0:36:14 > 0:36:16detectable from here on Earth.
0:36:17 > 0:36:20The trouble was telescopes at the time weren't capable of making
0:36:20 > 0:36:23accurate enough measurements.
0:36:23 > 0:36:24Astronomers would have to wait
0:36:24 > 0:36:28another 40 years for technology to improve.
0:36:28 > 0:36:32The first planet beyond our solar system was finally discovered
0:36:32 > 0:36:36in 1992, and it opened the floodgates.
0:36:37 > 0:36:40Within a decade, almost a hundred more had been found.
0:36:42 > 0:36:44Otto Struve's technique was brilliant.
0:36:44 > 0:36:46But it had one major flaw.
0:36:49 > 0:36:53It's much easier to spot a big wobble than a small one.
0:36:55 > 0:36:58The closer the planet is to the star, the bigger the wobble -
0:36:58 > 0:37:02but the hotter the planet will be.
0:37:02 > 0:37:06Every single one of the planets that had been found were searing hot,
0:37:06 > 0:37:08tortured worlds...
0:37:08 > 0:37:10with no chance of life.
0:37:14 > 0:37:18To find a planet like the Earth, orbiting at a safe distance
0:37:18 > 0:37:22from its star, astronomers needed to detect much smaller wobbles.
0:37:24 > 0:37:27With ordinary telescopes, that was impossible.
0:37:33 > 0:37:35But then, in 2003,
0:37:35 > 0:37:39a brand new planet hunting instrument was unveiled.
0:37:39 > 0:37:41Horizon was there to tell the story.
0:37:41 > 0:37:45Between the Andes mountains and the Pacific Ocean,
0:37:45 > 0:37:49on the remote southern edge of the Atacama Desert lies
0:37:49 > 0:37:51one of the most extraordinary observatories on Earth.
0:37:55 > 0:37:57The high elevation and the low rainfall,
0:37:57 > 0:38:00just one millimetre a year, makes it
0:38:00 > 0:38:04the perfect place for uninterrupted views of the southern night sky.
0:38:05 > 0:38:08Please come in. I have something to show you in here.
0:38:12 > 0:38:15Professor Stephane Udry is the proud owner of a machine which
0:38:15 > 0:38:18could change the course of human history.
0:38:19 > 0:38:22Inside this big box is an enclosure
0:38:22 > 0:38:26and inside this is a vacuum tank, with the instrument that is
0:38:26 > 0:38:30the most sensitive in the world now for planet detection.
0:38:30 > 0:38:35With this instrument we can detect low mass planet five,
0:38:35 > 0:38:37ten times the mass of the Earth.
0:38:37 > 0:38:38Can we go in?
0:38:38 > 0:38:42No. Of course not, because just opening the door will destroy
0:38:42 > 0:38:45the measurement for a few days.
0:38:45 > 0:38:49Because we need to have a very stable instrument to be able
0:38:49 > 0:38:54to repeat the measurement with the same precision day after day,
0:38:54 > 0:38:56month after month, years after years.
0:39:02 > 0:39:05And that's exactly what they've been doing.
0:39:07 > 0:39:10They drew up a list of a thousand targets
0:39:10 > 0:39:13taken from the Gliese Catalogue of Nearby Stars...
0:39:13 > 0:39:17and began measuring and re-measuring each candidate,
0:39:17 > 0:39:21hunting for wobbles that had previously been too small to detect.
0:39:32 > 0:39:35But one star caught Stephane's attention.
0:39:36 > 0:39:41Gliese 581 was in our target list since the beginning.
0:39:42 > 0:39:46Categorised as Gliese 581a,
0:39:46 > 0:39:49it's a Red Dwarf star, a third of the mass of our own sun.
0:39:54 > 0:39:58When the wobble was plotted it revealed 581b,
0:39:58 > 0:40:02a massive planet the size of Neptune, close into the star,
0:40:02 > 0:40:05and orbiting once every five and a half days.
0:40:07 > 0:40:09It was no Earth,
0:40:09 > 0:40:11but the star's wobble held some fine
0:40:11 > 0:40:13detail that still intrigued Stephane.
0:40:15 > 0:40:18We noticed that there was something else in the system.
0:40:19 > 0:40:23There seemed to be another, smaller planet lurking in the detail.
0:40:25 > 0:40:29That something else could be a five Earth-mass planet very close
0:40:29 > 0:40:30to the star.
0:40:32 > 0:40:34If Stephane's hunch was right,
0:40:34 > 0:40:38it would be the smallest planet ever detected around a distant sun.
0:40:39 > 0:40:42And this planet seemed to be habitable.
0:40:44 > 0:40:47We got excited because the distance was just right for the planet
0:40:47 > 0:40:49to possibly be in the habitable zone.
0:40:55 > 0:41:00After years of hunting, the search for Second Earth was over.
0:41:01 > 0:41:05European astronomers have spotted a new planet outside our solar
0:41:05 > 0:41:07system which closely resembles the planet Earth.
0:41:07 > 0:41:10The probability that there is life elsewhere in the universe
0:41:10 > 0:41:11goes up a bit.
0:41:11 > 0:41:14This latest find has set the world of astronomy alight.
0:41:17 > 0:41:21It is always very exciting to be the first one to know.
0:41:21 > 0:41:23It's like being in the spaceship
0:41:23 > 0:41:27coming to a planet and being the first one to see the landscape.
0:41:30 > 0:41:32So far, astronomers have searched just a tiny
0:41:32 > 0:41:34fraction of the stars in our galaxy,
0:41:34 > 0:41:39but they've already found five more potentially habitable worlds.
0:41:39 > 0:41:43That's five more chances that out there somewhere there is
0:41:43 > 0:41:45another Earth.
0:41:45 > 0:41:49And for every new world that astronomers discover,
0:41:49 > 0:41:52the dream of finding intelligent life gets a little closer.
0:42:00 > 0:42:04Science has completely transformed our understanding
0:42:04 > 0:42:07of the universe and most of those breakthroughs have been made
0:42:07 > 0:42:08right here on Earth.
0:42:08 > 0:42:11They've allowed us to explore alien worlds,
0:42:11 > 0:42:13to unlock the secrets of gravity,
0:42:13 > 0:42:17to discover the very origins of the universe itself.
0:42:17 > 0:42:21But it seems the deeper we look, the more questions we find
0:42:21 > 0:42:24and the more profound they become -
0:42:24 > 0:42:27questions that we've been asking for thousands of years,
0:42:27 > 0:42:29such as, "Where did we come from?"
0:42:30 > 0:42:33In the beginning there was nothing -
0:42:33 > 0:42:36no galaxies, no stars, not even atoms.
0:42:44 > 0:42:49Then 13.7 billion years ago, from nothing came everything.
0:42:50 > 0:42:52The universe burst into existence.
0:42:54 > 0:42:56We all came from the Big Bang.
0:42:56 > 0:42:58But how did it happen?
0:42:58 > 0:43:02How did the Big Bang actually create the atoms that make
0:43:02 > 0:43:06up our bodies, and the bodies of the planets and the stars?
0:43:09 > 0:43:11One inescapable fact is that we exist,
0:43:11 > 0:43:14so does the sun, the stars, the Earth and everything else.
0:43:14 > 0:43:16And no-one has yet explained how the matter
0:43:16 > 0:43:18came into existence in the first place, which adds force
0:43:18 > 0:43:21to my own contention that we are strong on the detail
0:43:21 > 0:43:24and weak on the fundamentals.
0:43:29 > 0:43:31Up until the 20th century,
0:43:31 > 0:43:35it was thought that the atom was the smallest particle in existence.
0:43:37 > 0:43:41Now we know that inside the atom live a whole host of particles
0:43:41 > 0:43:43that are even smaller still.
0:43:43 > 0:43:47The protons, neutrons and electrons. These particles
0:43:47 > 0:43:51are the building blocks from which everything in the universe is made.
0:43:53 > 0:43:56And somehow, they were forged from pure energy in the Big Bang.
0:43:59 > 0:44:02But how did that actually happen?
0:44:02 > 0:44:04How did energy become matter that we can touch?
0:44:08 > 0:44:11The answer could lie in a mysterious, invisible field.
0:44:15 > 0:44:18The best theory we have at the moment for the origin of mass
0:44:18 > 0:44:22for what makes stuff stuff is called the Higgs mechanism.
0:44:25 > 0:44:29And the Higgs mechanism works by filling the universe with...
0:44:29 > 0:44:31with a thing. It's almost like treacle.
0:44:36 > 0:44:37And by the universe,
0:44:37 > 0:44:41I don't just mean the void between the stars and the planets,
0:44:41 > 0:44:42I mean the room in front of you.
0:44:46 > 0:44:49Some particles move through the Higgs field
0:44:49 > 0:44:52and talk to the Higgs field and slow down,
0:44:52 > 0:44:55and they're the heavy particles. So all the particles that make
0:44:55 > 0:44:59up your body are heavy because they're talking to the Higgs field.
0:45:05 > 0:45:08Some other particles, like particles of light, photons,
0:45:08 > 0:45:12don't talk to the Higgs at all and move through at the speed of light.
0:45:22 > 0:45:26To prove that this strange, treacly field is real,
0:45:26 > 0:45:30scientists need to find the particle associated with it.
0:45:30 > 0:45:32They call it the Higgs particle.
0:45:35 > 0:45:36The problem is that this
0:45:36 > 0:45:40particular particle isn't exactly easy to find.
0:45:40 > 0:45:44If it exists at all, it's only for a fleeting moment.
0:45:44 > 0:45:48And the only way to see it is to travel 13.7 billion years back
0:45:48 > 0:45:52in time to moment it first flashed into existence - in the Big Bang.
0:45:54 > 0:45:56Needless to say, that's a bit tricky.
0:45:58 > 0:45:59But rather than give up,
0:45:59 > 0:46:03scientists came up with an extraordinary solution.
0:46:05 > 0:46:07They would conjure up the particle themselves,
0:46:07 > 0:46:11by recreating the conditions of the Big Bang here on Earth.
0:46:16 > 0:46:20They needed a burst of energy so powerful,
0:46:20 > 0:46:23it would mimic the moment of creation itself.
0:46:23 > 0:46:26And the best way to achieve that is to smash things
0:46:26 > 0:46:28together at phenomenal speeds.
0:46:33 > 0:46:38So they chose the tiny proton from the heart of the atom and set out
0:46:38 > 0:46:43to build the biggest proton smashing machine the world had ever seen.
0:46:59 > 0:47:0213.7 billion years after it all began...
0:47:04 > 0:47:07..we're about to go back to the beginning of time...
0:47:12 > 0:47:14..with the largest and most complex
0:47:14 > 0:47:17scientific experiment ever attempted.
0:47:19 > 0:47:24The Large Hadron Collider or LHC has just one simple
0:47:24 > 0:47:30but audacious aim - to recreate the conditions of the Big Bang...
0:47:32 > 0:47:34..in an attempt to answer the most
0:47:34 > 0:47:38profound questions about our universe.
0:47:40 > 0:47:44The goal of particle physics is to understand
0:47:44 > 0:47:47the universe in which we live.
0:47:47 > 0:47:51We want to understand why things are the way they are.
0:47:51 > 0:47:55How they work. What everything is. We want to understand.
0:47:59 > 0:48:02The large Hadron Collider spans the Swiss French border just
0:48:02 > 0:48:03outside Geneva.
0:48:05 > 0:48:09It's the largest particle accelerator ever constructed.
0:48:13 > 0:48:17It's down here in caverns brimming with the latest
0:48:17 > 0:48:19technology that the big bangs will be made.
0:48:30 > 0:48:32The bits of matter we're going to
0:48:32 > 0:48:34fire around the LHC are called protons.
0:48:37 > 0:48:41Not one, but four colossal particle detectors have been installed
0:48:41 > 0:48:46around the ring to take pictures of what happens when protons collide.
0:48:51 > 0:48:56Our theories predict that the Higgs particle is immensely heavy.
0:48:56 > 0:48:59And it's a general rule in particle physics
0:48:59 > 0:49:01that heavy particles are unstable.
0:49:01 > 0:49:05They simply fall apart into lighter particles.
0:49:05 > 0:49:08So if the Higgs is a real part of nature -
0:49:08 > 0:49:12it would have long ago vanished from the early universe.
0:49:12 > 0:49:16And today, even if we manage to recreate the Higgs,
0:49:16 > 0:49:17it'll disappear...
0:49:19 > 0:49:20..before we can see it.
0:49:22 > 0:49:27This is a simulation of a single proton-proton collision at the LHC.
0:49:27 > 0:49:32It's actually a simulation of the production of a Higgs particle.
0:49:32 > 0:49:34Now the Higgs particle you don't see of course,
0:49:34 > 0:49:37it just decays in a fraction of a second.
0:49:37 > 0:49:40But what you do see is the smoking gun.
0:49:40 > 0:49:44In this case, two very clear red tracks -
0:49:44 > 0:49:48these two particles here called muons that have gone straight to
0:49:48 > 0:49:50the very edges of the detector.
0:49:51 > 0:49:56And if we see not just one collision like this but maybe ten.
0:49:56 > 0:50:00maybe a hundred, then we'll have discovered the Higgs and for
0:50:00 > 0:50:03the first time we'll understand the origin of mass in the universe.
0:50:09 > 0:50:11That is, if the experiment works.
0:50:15 > 0:50:20On the 10th September 2008 the LHC was switched on and the first
0:50:20 > 0:50:24particles were smashed together at close to the speed of light.
0:50:25 > 0:50:31And in July 2012 the first glimpse of the Higgs particle was announced.
0:50:34 > 0:50:38Scientists hunting for the elusive Higgs boson
0:50:38 > 0:50:41say they've discovered strong signals that it exists...
0:50:41 > 0:50:44Say they've uncovered signs of the elusive Higgs boson,
0:50:44 > 0:50:46known as the God particle...
0:50:46 > 0:50:49Researchers presented results from two independent experiments...
0:50:49 > 0:50:51Evidence which helps them
0:50:51 > 0:50:54move closer to the building blocks of the universe.
0:51:00 > 0:51:04The results show that the mysterious Higgs field really exists,
0:51:04 > 0:51:07which means we now better understand how the matter that makes up
0:51:07 > 0:51:11the universe was formed, and why it is the way it is.
0:51:20 > 0:51:23You might think that staring into the face of creation would
0:51:23 > 0:51:27mark an end to science's quest to understand the universe,
0:51:27 > 0:51:30in fact it could just be the beginning.
0:51:30 > 0:51:33Once you understand how the Big Bang created us and created everything
0:51:33 > 0:51:38in the universe, you realise there's a much bigger even more profound
0:51:38 > 0:51:42question beyond it - and finding an answer to that will require
0:51:42 > 0:51:47more imagination, more intelligence, more determination than ever before.
0:51:47 > 0:51:50If the Big Bang created the universe -
0:51:50 > 0:51:52then what created the Big Bang?
0:52:06 > 0:52:09That question reveals a major problem with
0:52:09 > 0:52:11the idea of the Big Bang.
0:52:11 > 0:52:14It exposes the one part of the theory
0:52:14 > 0:52:17that just doesn't make any sense.
0:52:17 > 0:52:20How did everything apparently spring, unbidden, from nothing?
0:52:23 > 0:52:27The idea of "everything from nothing" is something that
0:52:27 > 0:52:32has occupied physicist Michio Kaku for much of his professional life.
0:52:33 > 0:52:35You know, the idea sounds impossible.
0:52:35 > 0:52:40preposterous. I mean, think about it, everything from nothing!
0:52:40 > 0:52:44The galaxies, the stars in the heavens coming from a pinpoint.
0:52:44 > 0:52:46I mean, how can it be?
0:52:46 > 0:52:49But you know, if you think about it a while,
0:52:49 > 0:52:53it all depends on how you define nothing.
0:52:57 > 0:53:00This is the biggest vacuum chamber in the world.
0:53:02 > 0:53:06It is here that NASA recreates the conditions of space on Earth.
0:53:10 > 0:53:12Its eight-feet-thick walls
0:53:12 > 0:53:15are made from 2,000 tonnes of solid aluminium.
0:53:19 > 0:53:23It takes two days of pumping out the air, and another week of
0:53:23 > 0:53:27freezing out the remaining molecules to create a near-perfect vacuum.
0:53:31 > 0:53:34A cathedral-sized volume of nothing.
0:53:35 > 0:53:38When they switch this place on,
0:53:38 > 0:53:43this is as close as we can get to a state of nothingness.
0:53:43 > 0:53:44Everywhere we look we see something.
0:53:44 > 0:53:48We see atoms, we see trees, we see forests, we see water.
0:53:48 > 0:53:53But hey, right here, we can pump all the atoms out,
0:53:53 > 0:53:57and this is probably the arena out of which genesis took place.
0:53:59 > 0:54:03Except, of course, it isn't quite that straightforward.
0:54:04 > 0:54:10For a start, the nothing created by NASA still has dimensions.
0:54:10 > 0:54:12This is nothing in 3-D.
0:54:15 > 0:54:20And the tests carried out within the chamber can, of course, be viewed.
0:54:20 > 0:54:22This is nothing through which light can travel.
0:54:27 > 0:54:29NASA's nothing has properties.
0:54:30 > 0:54:33This nothing is, in fact, something.
0:54:34 > 0:54:38So, for me, the universe did not come from absolute nothing,
0:54:38 > 0:54:42that is a state of no equations, no space, no time,
0:54:42 > 0:54:46it came from a pre-existing state, also a state of nothing
0:54:46 > 0:54:50that our universe did in fact come from this infinitesimal tiny
0:54:50 > 0:54:54explosion that took place, giving us the Big Bang and giving us
0:54:54 > 0:54:58the galaxies and stars we have today.
0:55:03 > 0:55:04For Professor Michio Kaku,
0:55:04 > 0:55:08the laws of physics did not arrive with the Big Bang.
0:55:10 > 0:55:13The appearance of matter did not start the clock of time.
0:55:14 > 0:55:16His interpretation of nothing tells him that there
0:55:16 > 0:55:20was, in short, a before.
0:55:25 > 0:55:27Most scientists now believe that there must have been
0:55:27 > 0:55:29something before the Big Bang.
0:55:31 > 0:55:34And understanding what that something was and how it
0:55:34 > 0:55:38worked is the new frontier in our quest to understand the universe.
0:55:44 > 0:55:49It occupies the minds of some of the greatest thinkers on the planet.
0:55:49 > 0:55:51And the solutions they've come up with
0:55:51 > 0:55:54stretch human imagination to its limits.
0:55:57 > 0:55:59You have Swiss cheese, OK?
0:55:59 > 0:56:04Just imagine that the cheesy part of it is heavy vacuum
0:56:04 > 0:56:08and the universe expands and these bubbles appear inside.
0:56:08 > 0:56:12The universe is born inside of a black hole.
0:56:13 > 0:56:15- String theory.- M-theory.
0:56:15 > 0:56:18Where M stands for magic, mystery or membrane.
0:56:18 > 0:56:21It's actually safe to create a universe in your basement.
0:56:21 > 0:56:25The Big Bang is the aftermath of some encounter
0:56:25 > 0:56:27between two parallel worlds.
0:56:30 > 0:56:33These theories sound pretty far-fetched.
0:56:33 > 0:56:35But then we are dealing with concepts
0:56:35 > 0:56:38that are almost beyond imagination.
0:56:38 > 0:56:41At the moment, they're fighting it out with no clear winner.
0:56:41 > 0:56:45So nobody can say for sure what caused the Big Bang.
0:56:50 > 0:56:53For the time being, this is as far as we can go.
0:57:07 > 0:57:10Science's quest to understand the universe is one of the greatest
0:57:10 > 0:57:14voyages of discovery that we've ever embarked on.
0:57:14 > 0:57:17But any explorer worth his salt will tell you that for every
0:57:17 > 0:57:21door that you open, another one lies beyond. Science has revealed
0:57:21 > 0:57:25a universe that is more beautiful, more extraordinary, than we ever
0:57:25 > 0:57:26could have imagined,
0:57:26 > 0:57:29but that journey for us is only just beginning.
0:58:03 > 0:58:05Subtitles by Red Bee Media Ltd