0:00:05 > 0:00:08In the first few years of the new millennium,
0:00:08 > 0:00:10this starkly strange building
0:00:10 > 0:00:13emerged from the Canadian countryside.
0:00:14 > 0:00:18In it are housed some of the most extreme minds in science.
0:00:18 > 0:00:21The ideas produced within the walls of this institution,
0:00:21 > 0:00:27are intended to shed new light on science's hardest problem.
0:00:27 > 0:00:31Is there an ultimate answer?
0:00:31 > 0:00:32I don't know.
0:00:32 > 0:00:35I don't even know if the question makes sense.
0:00:35 > 0:00:41They intend to tell us once and for all where we came from
0:00:41 > 0:00:46by unravelling the deepest mysteries of the birth of the universe.
0:00:46 > 0:00:50Time did not exist before the beginning.
0:00:50 > 0:00:54Somehow, time sprang into existence.
0:00:54 > 0:00:58Now, that's a notion which we have no grasp of
0:00:58 > 0:01:02and which may be a logical contradiction.
0:01:02 > 0:01:07They are re-writing science's story of creation.
0:01:07 > 0:01:09Why is it, all of a sudden, there are
0:01:09 > 0:01:11laws of nature, and where did they come from?
0:01:11 > 0:01:15Why these laws and not other laws?
0:01:19 > 0:01:23And they've concluded that one of the 20th century's
0:01:23 > 0:01:27greatest scientific ideas might have to be thrown out.
0:01:31 > 0:01:34There is certainly not big bang. That is impossible.
0:01:34 > 0:01:35I don't believe in that at all.
0:01:48 > 0:01:55For thousands of years, science has tied to understand the mysteries of the night sky.
0:01:57 > 0:02:02It is an awe-inspiring achievement that a certain kind of ape
0:02:02 > 0:02:06has discovered that it is living on a planet,
0:02:06 > 0:02:10that the planet is flying around a star in a galaxy.
0:02:13 > 0:02:20..and that that galaxy that is just one of a vast sea of galaxies in a near-infinite universe.
0:02:23 > 0:02:29But now it seems, science is about to go one step further
0:02:29 > 0:02:34with an idea that will make previous breakthroughs in cosmology
0:02:34 > 0:02:38pale into insignificance.
0:02:39 > 0:02:42It is the grandest concept imaginable,
0:02:42 > 0:02:47yet it has its roots in an notion that we are all familiar with.
0:02:48 > 0:02:51Cause.
0:02:51 > 0:02:53and effect.
0:02:53 > 0:02:55Cause.
0:02:56 > 0:02:58Effect.
0:02:58 > 0:03:00It's a simple, yet powerful idea.
0:03:04 > 0:03:08Because one thing follows another, we can stray from the present.
0:03:08 > 0:03:12We can boldly stride into the future,
0:03:12 > 0:03:15and confidently travel back in time.
0:03:18 > 0:03:23It's this idea that allowed American astronomer Edwin Hubble to draw
0:03:23 > 0:03:27a far-reaching conclusion to what he saw in the movement of galaxies.
0:03:27 > 0:03:33The discovery of the century had to be Edwin Hubble making his Hubble diagram.
0:03:33 > 0:03:38And what he did is he just plotted distance versus velocity, or speed, of the galaxy.
0:03:40 > 0:03:43And can you imagine one day making that plot
0:03:43 > 0:03:45and you discovered things further away
0:03:45 > 0:03:47were moving faster away from you?
0:03:47 > 0:03:49And this is the famous Hubble diagram
0:03:49 > 0:03:52which told us that the universe is expanding.
0:03:52 > 0:03:55This revolutionised our view of the universe.
0:03:55 > 0:03:58Not only was there a universe out there but now there was a universe
0:03:58 > 0:04:02that was expanding and it was getting bigger and bigger with time.
0:04:02 > 0:04:05And it didn't take long for someone to figure out,
0:04:05 > 0:04:09"If it's getting bigger with time, surely it started from somewhere."
0:04:09 > 0:04:12And this really brought out the first idea
0:04:12 > 0:04:15that there was a moment of creation
0:04:15 > 0:04:18i.e. the big bang.
0:04:23 > 0:04:27I think the discovery that the universe was expanding
0:04:27 > 0:04:29was one of the most significant in science.
0:04:29 > 0:04:35It's on a similar level to Darwin's discovery of evolution.
0:04:35 > 0:04:37It tells us the universe
0:04:37 > 0:04:40wasn't always the way it is today,
0:04:40 > 0:04:43it tells us we came from something,
0:04:43 > 0:04:45something violent,
0:04:45 > 0:04:47something extraordinary.
0:04:50 > 0:04:57The big bang is an elegant answer to the biggest question that science can ever ask.
0:04:57 > 0:04:59It's startling idea.
0:05:02 > 0:05:05It gives us a sense of origin.
0:05:05 > 0:05:11And however odd the notion sounds, it's a comfort to know exactly where we came from.
0:05:14 > 0:05:19Science assures us that our universe exploded into existence
0:05:19 > 0:05:2213.7 billion years ago.
0:05:24 > 0:05:29And thanks to cause and effect, science knows what happened
0:05:29 > 0:05:32right from the very beginning of the bang itself.
0:05:32 > 0:05:34Well, almost.
0:05:34 > 0:05:39So, in the standard picture, if this is the history of our universe,
0:05:39 > 0:05:43then this is where the big bang is.
0:05:43 > 0:05:44At t = 0.
0:05:44 > 0:05:46This is when the baby was born.
0:05:46 > 0:05:52And when the universe is somewhere here.
0:05:52 > 0:05:57where this is 10 to the power of -34th of this one second.
0:05:59 > 0:06:06So we know about the universe up until 0.0000341 seconds
0:06:06 > 0:06:09before it started.
0:06:09 > 0:06:11That's a pretty small number, isn't it?
0:06:11 > 0:06:15At this point, the classical theory would fail.
0:06:18 > 0:06:22The thing is, big bang doesn't quite work.
0:06:22 > 0:06:27So much so, that people are now starting to think the unthinkable -
0:06:27 > 0:06:31that big bang wasn't the beginning at all.
0:06:31 > 0:06:35How many people think that there was something before the big bang?
0:06:38 > 0:06:43Ten years ago, this would never have happened.
0:06:43 > 0:06:47Then, there was no doubt that "before the big bang"
0:06:47 > 0:06:52made no sense. But today, the certainty has gone.
0:06:55 > 0:06:58There is no escaping the inconvenient truth
0:06:58 > 0:06:59that Hubble's graph,
0:06:59 > 0:07:01work of genius though it is,
0:07:01 > 0:07:03contains a huge problem.
0:07:03 > 0:07:08It tells us that everything we see in the universe today -
0:07:08 > 0:07:12us, trees, galaxies,
0:07:12 > 0:07:17zebras, emerged in an instant from nothing.
0:07:24 > 0:07:26And that's a problem.
0:07:26 > 0:07:31It's all effect, and no cause.
0:07:31 > 0:07:33The idea of "everything from nothing"
0:07:33 > 0:07:37is something that has occupied physicist Michio Kaku
0:07:37 > 0:07:41for much of his professional life.
0:07:41 > 0:07:44You know, the idea sounds impossible.
0:07:44 > 0:07:48preposterous. I mean, think about it - everything from nothing!
0:07:48 > 0:07:49The galaxy,
0:07:49 > 0:07:53the stars in the heavens coming from a pinpoint.
0:07:53 > 0:07:56I mean how can it be? How can it be that everything comes from nothing?
0:07:56 > 0:08:00But you know, if you think about it a while,
0:08:00 > 0:08:04it all depends on how you define "nothing".
0:08:12 > 0:08:17In Sandusky, Ohio, is Plum Brook Station.
0:08:17 > 0:08:23It is here that NASA recreates the conditions of space on Earth,
0:08:23 > 0:08:26and part of that means generating nothing.
0:08:26 > 0:08:28..in vast quantities.
0:08:34 > 0:08:38This is the biggest vacuum chamber in the world.
0:08:46 > 0:08:52Its eight-feet-thick walls are made from 2,000 tons of solid aluminium.
0:08:55 > 0:08:59It takes two days of pumping out the air,
0:08:59 > 0:09:02and another week of freezing out the remaining molecules
0:09:02 > 0:09:05to create a near-perfect vacuum.
0:09:07 > 0:09:11A cathedral-sized volume of nothing.
0:09:12 > 0:09:15When they switch this place on,
0:09:15 > 0:09:20this is as close as we can get to a state of nothingness.
0:09:20 > 0:09:22Everywhere we look we see something.
0:09:22 > 0:09:25We see atoms, we see trees, we see forests, we see water.
0:09:25 > 0:09:29but hey, right here, we can pump all the atoms out,
0:09:29 > 0:09:34and this is probably the arena out of which genesis took place.
0:09:34 > 0:09:37So if you really understand the state of nothing,
0:09:37 > 0:09:40you understand everything about the origin of the universe.
0:09:43 > 0:09:46Except, of course, it isn't quite that straightforward.
0:09:46 > 0:09:51For a start, the "nothing" created by NASA
0:09:51 > 0:09:53still has dimensions -
0:09:53 > 0:09:55this is nothing in 3-D.
0:09:57 > 0:10:03And the tests carried out within the chamber can, of course, be viewed.
0:10:03 > 0:10:07This is nothing through which light can travel.
0:10:08 > 0:10:13NASA's "nothing" has properties.
0:10:13 > 0:10:18This "nothing" is, in fact, something.
0:10:18 > 0:10:21I think there are two kinds of nothing.
0:10:21 > 0:10:26First there is what I call absolute nothing, No equations, no space,
0:10:26 > 0:10:30no time, absence of anything that the human mind can conceive of,
0:10:30 > 0:10:33just "nothing", but then I think,
0:10:33 > 0:10:37"There is the vacuum, which is nothing but the absence of matter."
0:10:41 > 0:10:46Professor Kaku's version of nothing is a perfect vacuum where,
0:10:46 > 0:10:49on the face of it, there is only energy.
0:10:49 > 0:10:52But in a perfect vacuum,
0:10:52 > 0:10:55energy sometimes transforms itself,
0:10:55 > 0:10:59temporarily and briefly, into matter.
0:10:59 > 0:11:02It is one of these tiny explosions
0:11:02 > 0:11:07that might have kept going and ended up in the big bang.
0:11:07 > 0:11:12So for me, the universe did not come from "absolute nothing",
0:11:12 > 0:11:16that is a state of no equations, no space, no time,
0:11:16 > 0:11:20it came from a pre-existing state, also a state of nothing.
0:11:20 > 0:11:22That our universe did actually come from
0:11:22 > 0:11:25this infinitesimal tiny explosion that took place,
0:11:25 > 0:11:32giving us the big bang and giving us the galaxies and stars we have today.
0:11:35 > 0:11:38For Professor Michio Kaku,
0:11:38 > 0:11:42the laws of physics did not arrive with the big bang.
0:11:44 > 0:11:47The appearance of matter did not start the clock of time.
0:11:47 > 0:11:54His interpretation of "nothing" tells him that there was, in short, a "before".
0:11:54 > 0:12:01If he's right, there's an opportunity for a cause to have an effect after all.
0:12:07 > 0:12:11At Stanford University near San Francisco, Professor Andrei Lind
0:12:11 > 0:12:16believes that the big bang itself is a flawed concept,
0:12:16 > 0:12:22but one that holds tantalising clues to the "real" story of creation.
0:12:22 > 0:12:26The idea of the big bang was a very powerful idea,
0:12:26 > 0:12:29but, er, this idea chad its own problems.
0:12:29 > 0:12:30One of the problems -
0:12:30 > 0:12:33why the universe was as big as it is now?
0:12:33 > 0:12:37The second idea - who made it expand?
0:12:37 > 0:12:40What caused this explosion?
0:12:42 > 0:12:45Big Bang was clearly a very special explosion.
0:12:45 > 0:12:49Ordinary explosions are messy.
0:12:49 > 0:12:53This one produced a universe that wasn't messy at all.
0:12:53 > 0:12:55Our universe is "smooth" -
0:12:55 > 0:13:00it looks more or less the same in every direction.
0:13:04 > 0:13:09It was an observation that required a radical explanation.
0:13:09 > 0:13:14Professor Linde was one of the cosmologists who provided it.
0:13:14 > 0:13:20The idea was that, just after matter first appeared, rather than a messy explosion,
0:13:20 > 0:13:26there was instead a massive and unprecedented growth in the size of the universe.
0:13:26 > 0:13:30The process is called inflation.
0:13:31 > 0:13:33If one assumed that there was
0:13:33 > 0:13:39this period of exponential expansion of the universe,
0:13:39 > 0:13:41in some energetic, vacuum-like state,
0:13:41 > 0:13:44then you can explain why the universe is so large,
0:13:44 > 0:13:48why our universe is so smooth at the very large scale,
0:13:48 > 0:13:52why properties of the universe in different parts
0:13:52 > 0:13:54are so similar to each other.
0:13:54 > 0:13:58All of these questions can be addressed
0:13:58 > 0:13:59if one uses inflation.
0:14:03 > 0:14:07The big bang and inflation explained everything.
0:14:07 > 0:14:11the universe began with a matter-producing explosion.
0:14:11 > 0:14:15Then, inflation sped things up and smoothed things out for a while,
0:14:15 > 0:14:21before disappearing, to leave the gently-expanding universe we see today.
0:14:21 > 0:14:23Inflation was so successful
0:14:23 > 0:14:29that Linde began to wonder if the big bang was needed at all.
0:14:32 > 0:14:38Maybe it's easier to say that there was inflation from the very beginning.
0:14:38 > 0:14:41It was not difficult from the point of view of mathematics,
0:14:41 > 0:14:44it was a difficult psychological step
0:14:44 > 0:14:46to give it up.
0:14:50 > 0:14:52Linde's masterstroke was to cut the big bang
0:14:52 > 0:14:55out of the story altogether,
0:14:55 > 0:15:01and to envisage inflation as something from which our universe emerged.
0:15:01 > 0:15:04A pre-existing condition that has been there...
0:15:04 > 0:15:06well, forever.
0:15:08 > 0:15:10You have Swiss cheese, OK?
0:15:10 > 0:15:16And in Swiss cheese, we have these bubbles of air.
0:15:16 > 0:15:20OK? So just imagine that the cheesy part of it
0:15:20 > 0:15:24is heavy vacuum and the universe expands
0:15:24 > 0:15:27and these bubbles appear inside.
0:15:30 > 0:15:34And it looks like infinite universe inside.
0:15:38 > 0:15:45So for Linde, the big bang isn't really a starting point at all
0:15:45 > 0:15:49He thinks that it's simply the end of something else.
0:15:50 > 0:15:57The universe appeared out of the cheese of what he calls "eternal inflation",
0:15:57 > 0:16:01in an area where the inflation simply ran out of steam.
0:16:03 > 0:16:07This has huge implications.
0:16:07 > 0:16:10It means that when we look into the night sky,
0:16:10 > 0:16:13we see only a tiny piece of the story of existence.
0:16:13 > 0:16:18Our universe is not alone.
0:16:18 > 0:16:21There are others,
0:16:21 > 0:16:27all co-existing within the eternally-inflating super-universe of Linde's cheese.
0:16:27 > 0:16:30And he's counted them.
0:16:30 > 0:16:34We have calculated how many really different options
0:16:34 > 0:16:38you can see on the way of your travel.
0:16:38 > 0:16:40And what did that give you?
0:16:40 > 0:16:45And that gave us the number 10 to the degree 10 to the degree
0:16:45 > 0:16:4710 to the degree 7.
0:16:50 > 0:16:53This is a huge...
0:16:53 > 0:16:56absolutely enormous number.
0:16:56 > 0:17:01But that's what we got as a result of our calculations.
0:17:04 > 0:17:07Andrei Linde is a highly-respected scientist.
0:17:07 > 0:17:14His ideas of the multiverse, odd as they seem, are now within the scientific mainstream.
0:17:14 > 0:17:21For many cosmologists, eternal inflation is in itself a reasonable explanation
0:17:21 > 0:17:24of what existed before our universe.
0:17:25 > 0:17:26But for others,
0:17:26 > 0:17:28it's utter nonsense.
0:17:28 > 0:17:30It's too arbitrary.
0:17:30 > 0:17:32You can start it one way,
0:17:32 > 0:17:35another way, you can tweak the parameters
0:17:35 > 0:17:37to get whatever observations you want.
0:17:37 > 0:17:40This is very dissatisfying.
0:17:40 > 0:17:44I basically feel we are letting down our tradition
0:17:44 > 0:17:47of theoretical physics, which is the most precise,
0:17:47 > 0:17:51predictive, powerful area of science we know,
0:17:51 > 0:17:53and we've got to do better than this.
0:17:55 > 0:18:03Professor Turok runs the Perimeter Institute for fundamental physics research near Toronto in Canada.
0:18:04 > 0:18:08And you will get...one plus two!
0:18:08 > 0:18:11It is full of men and women
0:18:11 > 0:18:17trying hard to follow their leader's urgings to "do better".
0:18:17 > 0:18:22Eternal inflation is quite a different creature than ordinary inflation.
0:18:22 > 0:18:28Here, thinking about what happened before the big bang is all part of a day's work.
0:18:29 > 0:18:33And though most people think there was something before the big bang...
0:18:33 > 0:18:35How many people think there was
0:18:35 > 0:18:39a universe before the big bang which was much like this one?
0:18:39 > 0:18:41..no-one can quite agree on what,
0:18:41 > 0:18:45or even if there was a bang at all.
0:18:45 > 0:18:49I do believe that there is no big bang, but I don't know what is on the other side for sure.
0:18:49 > 0:18:53How much would you bet? Would you bet your house?
0:18:53 > 0:18:55- Would you bet, um... - LAUGHTER
0:18:55 > 0:19:00Param Singh is working on a theory that he hopes will shorten the odds.
0:19:00 > 0:19:04He's trying to overcome the same problem as everyone else,
0:19:04 > 0:19:10namely the rather inconvenient idea of everything emerging from nothing,
0:19:10 > 0:19:14one Thursday afternoon 13.7 billion years ago.
0:19:14 > 0:19:21But Param's ideas strike at the fundamental principles that cause all the problems in the first place.
0:19:21 > 0:19:24So if you believe the universe is expanding
0:19:24 > 0:19:26and if you look at its history,
0:19:26 > 0:19:29then the universe must have expanded from something.
0:19:29 > 0:19:31And if you look backward and backward,
0:19:31 > 0:19:32what big-bang theory tells you
0:19:32 > 0:19:35is that the universe starts expanding from nothing.
0:19:38 > 0:19:43The principle mathematical objection is that, as the clock is wound back,
0:19:43 > 0:19:46and Hubble's zero hour is approached,
0:19:46 > 0:19:50all the stuff of the universe is crammed into a smaller and smaller space.
0:19:50 > 0:19:55Eventually, that space will become infinitely small.
0:19:55 > 0:20:00And in mathematics, invoking infinity is the same as giving up.
0:20:00 > 0:20:03Or cheating.
0:20:03 > 0:20:08Even if the mathematical laws would not have broken down at this point,
0:20:08 > 0:20:11even then it's philosophically very incomplete,
0:20:11 > 0:20:14like, how can something just originate from nothing?
0:20:14 > 0:20:16And that is what the theory has to explain.
0:20:21 > 0:20:29It's Param's job to understand how the unimaginably large emerged from the infinitesimally small.
0:20:29 > 0:20:34But it's not just philosophy and infinity that stands in his way.
0:20:35 > 0:20:40If you look at our universe which is at large scales, the mathematics that we know
0:20:40 > 0:20:44from Einstein's' theory very well describes most of the phenomena -
0:20:44 > 0:20:49all of the phenomena. Like this ball which I throw up - it comes back.
0:20:49 > 0:20:52But if I want to describe what is inside this ball,
0:20:52 > 0:20:54the atomic structure of the ball,
0:20:54 > 0:20:57or how the molecules are made and how atoms are made,
0:20:57 > 0:20:59what are their fundamental constituents,
0:20:59 > 0:21:04then I don't use classical gravity, I use a completely different physics called quantum mechanics.
0:21:04 > 0:21:11If I look at the universe, and I ask the question, I want to describe how it came from nothing,
0:21:11 > 0:21:14what was its nature when it was very small,
0:21:14 > 0:21:19then I have to use both the classical gravity and quantum mechanics and they don't talk to each other.
0:21:19 > 0:21:22What I need is a new theory, a new mathematics.
0:21:22 > 0:21:24And that is the biggest problem to find.
0:21:27 > 0:21:31Param Singh has been working on a way to combine the two systems.
0:21:31 > 0:21:37A scheme that works in the very big AND the very small.
0:21:37 > 0:21:42What he's found is that the maths predicts a very peculiar phenomenon.
0:21:42 > 0:21:45What we find is, that gravitational force,
0:21:45 > 0:21:49which is attractive, becomes repulsive when the universe is very small.
0:21:49 > 0:21:51That is predicted by the mathematics,
0:21:51 > 0:21:57the new mathematics which we obtain by the marriage of quantum mechanics and Einstein's gravity.
0:21:57 > 0:22:00It is a completely different paradigm now.
0:22:02 > 0:22:05The problem of the big-bang infinities
0:22:05 > 0:22:09are swept away by the new "repulsive" gravity.
0:22:09 > 0:22:11The point of "everything in nothing"
0:22:11 > 0:22:16is never reached.
0:22:16 > 0:22:18The maths is here,
0:22:18 > 0:22:22so this is one of the equations which took a couple of years to derive
0:22:22 > 0:22:23and the part in orange
0:22:23 > 0:22:26is the one that is predicted by Einstein's theory
0:22:26 > 0:22:27and the part in the white
0:22:27 > 0:22:30is the corrections which come from quantum gravity.
0:22:30 > 0:22:32So if you look at this orange part,
0:22:32 > 0:22:35this orange part tells you that if you look at the universe,
0:22:35 > 0:22:39which is becoming smaller and smaller as you approach big bang,
0:22:39 > 0:22:42the left-hand side and the right-hand side,
0:22:42 > 0:22:43they both become infinity.
0:22:43 > 0:22:47And we know that whenever we encounter infinity in mathematics,
0:22:47 > 0:22:49something has gone terribly wrong.
0:22:49 > 0:22:53So what quantum gravity gives us is this expression,
0:22:53 > 0:22:58which ensures that as we approach the big bang,
0:22:58 > 0:23:02when the universe is becoming smaller and smaller, both sides become zero,
0:23:02 > 0:23:06and after that, the universe starts expanding again
0:23:06 > 0:23:10on the other direction and the same laws remain valid.
0:23:10 > 0:23:13- Problem solved.- Problem solved.
0:23:15 > 0:23:20In Param Singh's scheme, instead of emerging from nothing,
0:23:20 > 0:23:23our universe owes its existence to a previous one
0:23:23 > 0:23:26that had the misfortune to collapse in on itself,
0:23:26 > 0:23:28then, thanks to some clever maths,
0:23:28 > 0:23:31rebounded to become what we see today.
0:23:33 > 0:23:37So the big bang was not a bang at all.
0:23:37 > 0:23:40It was, rather, a big bounce.
0:23:40 > 0:23:45It's a surprising thing, a bouncing universe, but in nature,
0:23:45 > 0:23:48if you look around us, there are lots of cycles, always happening,
0:23:48 > 0:23:50like we have seasons,
0:23:50 > 0:23:53we have even the motion of planets around sun.
0:23:53 > 0:23:58In fact, nature tries to prefer things were just cyclic in a way.
0:23:58 > 0:24:01But if we look at the whole lifespan of the age of the universe,
0:24:01 > 0:24:07which is billions of years, then maybe these cycles or the bounces, may not at all be surprising,
0:24:07 > 0:24:10and these are just the cycles of weather,
0:24:10 > 0:24:11in a way, for the universe,
0:24:11 > 0:24:14of going through contraction and expansion
0:24:14 > 0:24:16and contraction and expansion and so on.
0:24:21 > 0:24:27Of course, it might all be nothing more than a fantasy world of maths and little else.
0:24:27 > 0:24:30And there's always the nagging question
0:24:30 > 0:24:34of what started the infinite bouncing in the first place.
0:24:34 > 0:24:39Well, that's the most important question and I don't know the answer to that.
0:24:39 > 0:24:43Maybe very soon we'll find an answer to how it all started.
0:24:43 > 0:24:47- But it wasn't big bang? - It was certainly not big bang,
0:24:47 > 0:24:50that is impossible, I don't believe in that at all.
0:25:01 > 0:25:07Down the corridor from Param Singh is the office of Lee Smolin.
0:25:08 > 0:25:10But Professor Smolin rarely uses it.
0:25:10 > 0:25:15He's more usually to be found doing his thinking elsewhere.
0:25:20 > 0:25:24For him, the very idea of "everything from nothing" -
0:25:24 > 0:25:28the so-called "singularity" - points to a lack of understanding.
0:25:32 > 0:25:37I strongly, strongly believe
0:25:37 > 0:25:39that there was a period before the big bang,
0:25:39 > 0:25:42that the singularity was eliminated.
0:25:42 > 0:25:45To me, the singularity is not an indication
0:25:45 > 0:25:47that there was a first moment of time -
0:25:47 > 0:25:49it's an indication
0:25:49 > 0:25:52that general relativity is an incomplete theory.
0:25:52 > 0:25:55It's general relativity shouting at us,
0:25:55 > 0:25:57screaming at us, "I am not the end."
0:25:57 > 0:25:59There is more to understand.
0:26:03 > 0:26:09In his bid to further his own understanding of the cosmology,
0:26:09 > 0:26:14Professor Smolin has cast his scientific net wide.
0:26:14 > 0:26:17And, though he shares a lot of ground with Param Singh,
0:26:17 > 0:26:20and even Andrei Linde,
0:26:20 > 0:26:24his interpretation of what happened before the big bang
0:26:24 > 0:26:28owes more to Charles Darwin than to Albert Einstein.
0:26:31 > 0:26:36The idea works by analogy to how biology works.
0:26:36 > 0:26:39It says that the universe has an ancestor,
0:26:39 > 0:26:41which is another universe.
0:26:41 > 0:26:46How is the universe born from the ancestor?
0:26:46 > 0:26:48According to this hypothesis,
0:26:48 > 0:26:52the universe is born inside of a black hole.
0:26:55 > 0:26:59A black hole is a star which collapses,
0:26:59 > 0:27:07where everything becomes infinite and time stops.
0:27:07 > 0:27:10There is a bounce inside of every black hole.
0:27:11 > 0:27:13The material contracts
0:27:13 > 0:27:17and contracts and contracts again and then begins to expand again.
0:27:19 > 0:27:25And that is the big bang which initiates a new region of the universe.
0:27:27 > 0:27:34Smolin's natural selection idea proposes that for a universe to prosper, it must reproduce.
0:27:34 > 0:27:38And for that to happen it must contain black holes,
0:27:38 > 0:27:43that according to Smolin, spawn offspring universes.
0:27:44 > 0:27:50Before the big bang was another universe much like our own.
0:27:50 > 0:27:56In that universe there was a big cloud of gas and dust.
0:27:56 > 0:28:00It collapsed to form a big massive star,
0:28:00 > 0:28:05that star exploded, it left behind a black hole,
0:28:05 > 0:28:08and in that black hole there was a region,
0:28:08 > 0:28:11if you were misfortunate enough to fall in,
0:28:11 > 0:28:14you would find it becoming denser and denser and denser.
0:28:14 > 0:28:17You wouldn't survive this, but let's imagine you did.
0:28:17 > 0:28:18And all of a sudden,
0:28:18 > 0:28:22it would explode again and that would be our big bang.
0:28:25 > 0:28:30It's a beguilingly simple, and controversial combination of two
0:28:30 > 0:28:34of the greatest scientific breakthroughs of the modern age.
0:28:34 > 0:28:41I think that the theoretical evidence is moving towards this idea.
0:28:41 > 0:28:43And that's good.
0:28:43 > 0:28:46That gives me some confidence for the future.
0:28:47 > 0:28:53Professor Smolin is convinced that the big bang was not the beginning.
0:28:53 > 0:29:00And until his theory of cosmological natural selection is conclusively proven, he's committed
0:29:00 > 0:29:06to pursuing all avenues that might provide answers to what came before.
0:29:06 > 0:29:11I think the only way to keep going in this business is to go
0:29:11 > 0:29:15under the assumption that tomorrow's idea will be the best one so far.
0:29:15 > 0:29:16So I'm trying!
0:29:22 > 0:29:29Ten years ago, the only idea in cosmology was the unexplained big bang followed by inflation.
0:29:31 > 0:29:37"Pre-big bang" was only talked about behind closed doors by radicals.
0:29:39 > 0:29:42But today it's almost mainstream.
0:29:45 > 0:29:49Yeah, we just have to replace this with this.
0:29:49 > 0:29:51Back at the Perimeter Institute,
0:29:51 > 0:29:58there are any number of strange ideas about how our universe was born.
0:29:58 > 0:30:05And perhaps the strangest of all comes from the Institute's director, Professor Neil Turok.
0:30:07 > 0:30:10There are essentially two possibilities at the beginning.
0:30:10 > 0:30:14Either time did not exist before the beginning,
0:30:14 > 0:30:17somehow time sprang into existence.
0:30:19 > 0:30:23Now that's a notion which we have no grasp of
0:30:23 > 0:30:28and which may be a logical contradiction.
0:30:28 > 0:30:34The other possibility is that this event which initiated our universe
0:30:34 > 0:30:37was a violent event in a pre-existing universe.
0:30:39 > 0:30:41Professor Turok and his colleagues
0:30:41 > 0:30:47have come up with a model that assumes a complex version of existence,
0:30:47 > 0:30:52requiring ten spatial dimensions, plus time. Simple(!)
0:30:52 > 0:30:56What is present in these models, the picture of the world in these models,
0:30:56 > 0:31:01is that we live on an extended object called the brane.
0:31:01 > 0:31:05And a brane, it's B-R-A-N-E, short for membrane.
0:31:09 > 0:31:12But it's a membrane which is three-dimensional.
0:31:19 > 0:31:22All of space that we live in is part of this brane.
0:31:26 > 0:31:30And within these models you have to have at least two of these branes.
0:31:30 > 0:31:34You can't have only one, there have to be at least two.
0:31:34 > 0:31:40And they are separated by a little gap along a fourth dimension of space.
0:31:40 > 0:31:43It's not one of our existing dimensions.
0:31:43 > 0:31:48And basically within these models, these two branes can collide.
0:31:51 > 0:31:54When they collide, they remain extended.
0:31:54 > 0:31:57It's not all of space shrinking to a point.
0:31:57 > 0:32:01They fill with a density of plasma and matter, but it's finite.
0:32:01 > 0:32:04Everything is a definite number,
0:32:04 > 0:32:09which you can calculate, and which you can then
0:32:09 > 0:32:13describe using definite mathematical laws,
0:32:13 > 0:32:17and so that's the essential picture of the big bang in our model.
0:32:18 > 0:32:24And I think it's becoming a real alternative to the conventional picture
0:32:24 > 0:32:28that everything was created at the big bang.
0:32:28 > 0:32:34For many cosmologists, this is mathematical sleight of hand,
0:32:34 > 0:32:40and an unwelcome distraction to the serious business of improving on the tried and tested.
0:32:40 > 0:32:42What happens is that the authors
0:32:42 > 0:32:45are producing one version of the theory after another.
0:32:45 > 0:32:49Usually the lifetime of their ideas is about one year,
0:32:49 > 0:32:52after which it is replaced by the new set of ideas,
0:32:52 > 0:32:55then by another set of ideas, then still by another set of ideas.
0:32:55 > 0:32:58Not because they want to replace it,
0:32:58 > 0:33:01but because the previous versions were disproved
0:33:01 > 0:33:03by investigation of other people.
0:33:03 > 0:33:09So that is something which unless the whole line of research
0:33:09 > 0:33:14and claims and statements, will become more accurate.
0:33:14 > 0:33:17This is something which undermines the whole idea.
0:33:21 > 0:33:25So far just about every prediction made by inflationary theory
0:33:25 > 0:33:29has checked out in many, many observations.
0:33:29 > 0:33:33So it's not surprising that people like Andrei Linde are sometimes irritated
0:33:33 > 0:33:40by what they sees as speculative mathematical attacks on inflation.
0:33:40 > 0:33:43But it's not quite a done deal.
0:33:44 > 0:33:48And while there is any doubt, the likes of Neil Turok feel
0:33:48 > 0:33:51that it is their duty to point out where those doubts lie.
0:33:51 > 0:33:58They are basing their theory on shaky foundations.
0:33:58 > 0:34:02They cannot explain what happens before inflation.
0:34:02 > 0:34:08And I think they've got themselves into a whole host of puzzles
0:34:08 > 0:34:11to do with eternal inflation, and in a sense,
0:34:11 > 0:34:13not being able to predict anything.
0:34:13 > 0:34:17So I feel that we ARE being constructive.
0:34:17 > 0:34:20We're putting forward an alternative, one which can be proven wrong,
0:34:20 > 0:34:24and one which I think
0:34:24 > 0:34:29may in time become much more complete and satisfying
0:34:29 > 0:34:31than the theory of inflation.
0:34:47 > 0:34:53Ever since the idea of the big bang, people have wondered what caused it.
0:34:53 > 0:34:56What made everything apparently spring un-bidden from nothing?
0:35:05 > 0:35:08Might it be that Neil Turok's right,
0:35:08 > 0:35:12that the miracle was due to colliding branes in another dimension?
0:35:14 > 0:35:16Or perhaps Lee Smolin has the answer.
0:35:16 > 0:35:24Our big bang was simply the other side of a black hole in a galaxy far, far away.
0:35:26 > 0:35:32Maybe it would be best, like Michio Kaku, to stop thinking of nothing as nothing,
0:35:32 > 0:35:35but rather as just absence of stuff,
0:35:35 > 0:35:42and to imagine bubbles of matter forming in a high-energy vacuum.
0:35:42 > 0:35:44Is Param Singh correct?
0:35:44 > 0:35:46No big bang at all,
0:35:46 > 0:35:47just the big bounce,
0:35:47 > 0:35:53again, and again, and again.
0:35:56 > 0:36:01Or should we subscribe to Andrei Linde's Swiss cheese model,
0:36:01 > 0:36:07and redefine the big bang as simply the inflationary energy of a mega-verse dying out?
0:36:07 > 0:36:14Ten to the power ten to the power ten to the power seven times.
0:36:19 > 0:36:23All of these ideas stray from the standard model of cosmology,
0:36:23 > 0:36:29which holds that everything emerged from nothing at the point of the big bang.
0:36:29 > 0:36:34And they would be easier to dismiss as the half-baked musings of the lunatic fringe,
0:36:34 > 0:36:39were it not for the fact that some of the very people who constructed
0:36:39 > 0:36:46the everything from nothing big bang model are themselves starting to dismantle it.
0:36:53 > 0:36:57For many years, Professor Sir Roger Penrose spent much of his time
0:36:57 > 0:37:04dismissing the very idea of "before the big bang" as a complete non-starter.
0:37:05 > 0:37:10If people would ask me what happened before the big bang, my normal answer would be to say,
0:37:10 > 0:37:13"The word before. What does that mean?"
0:37:13 > 0:37:16Well, that's a sort of temporal concept.
0:37:16 > 0:37:20And if the big bang was a singularity in space-time,
0:37:20 > 0:37:25that means the very notion of time loses its meaning at this event,
0:37:25 > 0:37:28this so-called big bang.
0:37:28 > 0:37:30So if the notion of time loses its meaning,
0:37:30 > 0:37:32the very notion of before loses its meaning.
0:37:32 > 0:37:33So we would tend to say
0:37:33 > 0:37:36it's a meaningless question to ask for before,
0:37:36 > 0:37:39there wasn't a before, that's the wrong kind of notion.
0:37:39 > 0:37:42And I would have perhaps gone along with this point of view,
0:37:42 > 0:37:45until I've had some different ideas more recently.
0:37:47 > 0:37:54Professor Penrose has concluded that to understand the origin of the big bang,
0:37:54 > 0:37:57science needs to study the end of the universe.
0:37:58 > 0:38:03The present picture of the universe is that it starts with a big bang,
0:38:03 > 0:38:06and it ends with an indefinitely expanding,
0:38:06 > 0:38:08exponentially expanding universe,
0:38:08 > 0:38:10where in the remote future it cools off,
0:38:10 > 0:38:12and there's not much left except photons.
0:38:19 > 0:38:22Now what I'm saying is that in this remote future,
0:38:22 > 0:38:26the photons have no way of keeping time and they don't have any mass.
0:38:28 > 0:38:34You need mass to make a clock, and you have to have a clock to measure the scale of the universe.
0:38:34 > 0:38:37So the universe loses track of how big it is.
0:38:37 > 0:38:39And this very expanded universe
0:38:39 > 0:38:43becomes equivalent to a big bang of another one.
0:38:43 > 0:38:47So I'm saying that this, what we think of our present universe
0:38:47 > 0:38:50is but one eon of a succession of eons
0:38:50 > 0:38:56where this remotely expanding universe of each becomes the big bang of the next.
0:38:59 > 0:39:03So small and big become completely equivalent.
0:39:09 > 0:39:11If Professor Penrose is right,
0:39:11 > 0:39:18our universe's expansion means that all its mass will eventually be converted to energy.
0:39:18 > 0:39:23When that happens, conventional ideas of time and size disappear.
0:39:26 > 0:39:29The contention is that because of this,
0:39:29 > 0:39:31a nearly infinitely large universe
0:39:31 > 0:39:36could just as well be the infinitely small starting point for the next one.
0:39:38 > 0:39:43A cyclic system with a before and an after.
0:39:45 > 0:39:53It's quite a volte-face for a man who was until five years ago a pre-big bang denier.
0:39:53 > 0:39:57Let me say that a change of mind is not something unpleasant, I find,
0:39:57 > 0:39:58it's something exhilarating.
0:39:58 > 0:40:02Because you get stuck in a rut and that's what I find, you know,
0:40:02 > 0:40:04you're thinking about certain things,
0:40:04 > 0:40:07and after a while you think you're stuck into this rut.
0:40:07 > 0:40:12And a change of mind, you think, "Ah, why didn't I think of it like that?"
0:40:12 > 0:40:14That's extraordinarily exhilarating.
0:40:17 > 0:40:20It is a huge turnaround.
0:40:20 > 0:40:23For 50 years, the big bang,
0:40:23 > 0:40:30stating that everything including space and time emerged from nothing, has been scientific fact.
0:40:32 > 0:40:36And though what Professor Penrose and the others are suggesting is revolutionary,
0:40:36 > 0:40:42it's worth remembering that revolutions in cosmology have happened before.
0:40:44 > 0:40:49500 years ago, anyone suggesting that the earth orbited the sun would have been ridiculed,
0:40:49 > 0:40:52and then arrested.
0:40:56 > 0:40:58But from Copernicus to Galileo...
0:41:02 > 0:41:04..from Hubble to Hawking,
0:41:04 > 0:41:12the emerging cosmology has opened our eyes in stages to a bigger, truer picture.
0:41:12 > 0:41:20What is now being proposed is nothing less than the promise of the biggest picture yet.
0:41:20 > 0:41:23Probably the biggest picture possible.
0:41:25 > 0:41:30But in science, ideas are just ideas until they are confirmed
0:41:30 > 0:41:34or denied by observations.
0:41:34 > 0:41:41And because the pre big bang ideas are so radical, the race to back them up is intense.
0:41:42 > 0:41:48In rural England, there's a project under way that could seriously undermine inflation,
0:41:48 > 0:41:51the mainstay of the current cosmology.
0:41:51 > 0:41:57What we're doing today is building part of the world's biggest radio telescope.
0:41:57 > 0:41:59Which will allow us to look back
0:41:59 > 0:42:02to about a billion years after the big bang.
0:42:02 > 0:42:08So we'll get a glimpse of the universe in its adolescent years.
0:42:13 > 0:42:20Professor Bob Nichol is part of a team of academics constructing a new generation of radio telescope.
0:42:24 > 0:42:29It's called the Low Frequency Array - LOFAR.
0:42:29 > 0:42:35And though it lacks the iconic beauty of the 25 metre dish whose site it shares...
0:42:38 > 0:42:43..its scientific ambition more than makes up for the aesthetic disappointment.
0:42:46 > 0:42:50One of the foundations of cosmology is inflation.
0:42:50 > 0:42:56And one of the great things about inflation is that it says on the largest scales in the universe,
0:42:56 > 0:42:58the universe should be random,
0:42:58 > 0:43:02and the galaxies and the matter should be distributed randomly.
0:43:02 > 0:43:05So what we can do with this telescope is check that.
0:43:05 > 0:43:08And if we don't see it, if it's not random,
0:43:08 > 0:43:12then that's going to set the cat amongst the pigeons,
0:43:12 > 0:43:15and someone's going to have to come up with a better idea
0:43:15 > 0:43:19for what could have caused that non-randomness in the universe.
0:43:19 > 0:43:26- What do you think?- Ah, I think... I'm not paid to think.
0:43:26 > 0:43:29I'm paid to make the observations.
0:43:29 > 0:43:32I would love it, I would love it to be non-random.
0:43:32 > 0:43:38That would just be fantastic, right? It would really just give us something new to think about.
0:43:38 > 0:43:42And that's what being a scientist's all about.
0:43:42 > 0:43:44If LOFAR removes inflation,
0:43:44 > 0:43:49the whole of the standard model of cosmology would be called into question.
0:43:49 > 0:43:54But if it confirms inflation, it will not only support the standard model,
0:43:54 > 0:43:59it will leave most of the competing theories intact as well.
0:43:59 > 0:44:07To settle those arguments, the ambition is nothing less than to observe the big bang itself.
0:44:13 > 0:44:18Of course, we're 13.7 billion years too late to witness the actual event.
0:44:18 > 0:44:24But in a quiet corner of Louisiana, they're looking for the next best thing.
0:44:27 > 0:44:31They're hunting for gravity waves.
0:44:31 > 0:44:38But gravity waves are such slight and shy beasts that finding them has not been easy,
0:44:38 > 0:44:42even in the relative peace of rural Louisiana.
0:44:43 > 0:44:47This is LIGO,
0:44:47 > 0:44:51the Laser Interferometer Gravitational Wave Observatory...
0:44:53 > 0:45:01..where Joe Giaimi is sniffing out the reluctant gravity waves with laser beams and mirrors.
0:45:01 > 0:45:03This concrete enclosure
0:45:03 > 0:45:09protects the stainless steel vacuum tube that encloses our beam,
0:45:09 > 0:45:12and it goes on for the next four kilometres.
0:45:12 > 0:45:14How come it has to be so long?
0:45:14 > 0:45:17Well, the way gravitational waves work,
0:45:17 > 0:45:20the longer the distance you measure,
0:45:20 > 0:45:24the larger the change in that length you see.
0:45:25 > 0:45:31And four kilometres was chosen because we could afford it, and we could find a plot of land that big.
0:45:34 > 0:45:40A gravity wave is thought to be produced when cataclysmic events take place,
0:45:40 > 0:45:42like the big bang.
0:45:46 > 0:45:48OK, let's go.
0:45:48 > 0:45:53The gravity waves that are theoretically produced by such an event
0:45:53 > 0:45:58are thought to warp the very fabric of space and time.
0:45:58 > 0:46:04And it's this warping that Joe is hoping to measure with LIGO.
0:46:04 > 0:46:08LIGO generates a laser beam which is split into two
0:46:08 > 0:46:12and then reflected off mirrors at the end of each 4km tunnel.
0:46:13 > 0:46:16When the beams arrive back at the start of their journey,
0:46:16 > 0:46:19they should still be in sync with each other.
0:46:19 > 0:46:22If they're not, it might be that a gravity wave
0:46:22 > 0:46:27has temporarily changed the relative lengths of LIGO's arms.
0:46:27 > 0:46:28A bit.
0:46:30 > 0:46:33The difference between those two lengths,
0:46:33 > 0:46:37we're sensitive to that by less than 10 in the minus 18 metres.
0:46:37 > 0:46:42So if this arm length were to change with respect to that arm length
0:46:42 > 0:46:46bigger than that, bigger than 10 in the minus 18 metres, we could see it.
0:46:46 > 0:46:48And what does that equate to?
0:46:48 > 0:46:5310 in the minus 18 metres is 1/1,000 the diameter of a proton,
0:46:53 > 0:46:57or 1/1,000 the diameter of the smallest atomic nucleus,
0:46:57 > 0:46:59the nucleus of a hydrogen atom.
0:46:59 > 0:47:02- And you can measure that?- Yes.
0:47:06 > 0:47:1024 hours a day, 7 days a week,
0:47:10 > 0:47:14a patient band of physicists watch over the signal in shifts.
0:47:16 > 0:47:20So while we're taking data, we always have two people in the control room.
0:47:20 > 0:47:23TRAIN WHISTLE
0:47:23 > 0:47:25Can I just stop there? What was train whistle?
0:47:25 > 0:47:28OK, so... All right.
0:47:28 > 0:47:34When we lose lock, which is what just happened,
0:47:34 > 0:47:41that little train whistle goes off, because usually when we lose lock it's because of a train.
0:47:41 > 0:47:43TRAIN WHISTLE
0:47:45 > 0:47:52With tolerances so fine, measurement can be affected by almost anything that moves on earth.
0:47:52 > 0:47:57Freight trains passing five miles away...
0:47:57 > 0:47:59TRAIN WHISTLE
0:47:59 > 0:48:02..means that operations cease.
0:48:03 > 0:48:05So if we...
0:48:05 > 0:48:08ALARM RINGS
0:48:08 > 0:48:09Tornado warning.
0:48:14 > 0:48:20Though the technology is in its infancy, its potential is huge.
0:48:20 > 0:48:25LIGO is, in short, a prototype big bang detector.
0:48:37 > 0:48:40And once the concept is proved on earth,
0:48:40 > 0:48:43another interferometer will be built in space,
0:48:43 > 0:48:47where arms three million miles long
0:48:47 > 0:48:54will intercept the remains of the gravity waves theoretically produced at the beginning of time.
0:48:56 > 0:48:58And it could go even further.
0:48:58 > 0:49:02It could be that hidden in the signature of that first wave
0:49:02 > 0:49:06is contained evidence of previous big bangs.
0:49:08 > 0:49:15Good news perhaps for Param Singh and Roger Penrose when the satellites eventually fly.
0:49:23 > 0:49:29It is the holy grail of science to turn theory into fact with concrete observations,
0:49:29 > 0:49:36and for pre-big bang ideas, the evidence is proving frustratingly elusive.
0:49:36 > 0:49:39But there is a scientist who believes that her idea
0:49:39 > 0:49:46has actually has been backed up by not one, but three observations already.
0:49:46 > 0:49:52Laura Mersini-Houghton's radical theory materialised, quite suddenly, in 2006.
0:49:55 > 0:49:57I was teaching early at 8am in the morning.
0:49:57 > 0:50:02And it was one of those large classes with about 100 students.
0:50:02 > 0:50:06I'm not an early riser, so I wasn't happy about it.
0:50:06 > 0:50:11However, I did manage to come and teach, and was done by 9am.
0:50:11 > 0:50:15So I thought, "I deserve a coffee.
0:50:15 > 0:50:19"Time for a coffee to wake up and plan the rest of the day."
0:50:23 > 0:50:27Of course I'd been thinking about the big questions of cosmology.
0:50:27 > 0:50:33Why did we start with this big bang and what was there before?
0:50:38 > 0:50:43And suddenly this idea comes.
0:50:44 > 0:50:48It was an idea that emerged from the fact that it's possible
0:50:48 > 0:50:52to represent the entire universe not as an object,
0:50:52 > 0:50:57but mathematically, as a wave.
0:50:57 > 0:51:02Dr Mersini-Houghton's idea was to manipulate the mechanics of that waveform
0:51:02 > 0:51:07with a branch of mathematics called string theory.
0:51:07 > 0:51:14It seemed to provide an elegant solution as to why our universe emerged in the first place.
0:51:14 > 0:51:18when you do that, and you calculate how that wave form evolves,
0:51:18 > 0:51:22you do end up with the high energy big bang.
0:51:26 > 0:51:32It seemed such a simple idea that in one hand I was very excited about it,
0:51:32 > 0:51:36at the simplicity of the idea, and the fact that it gave a very coherent picture
0:51:36 > 0:51:39of connecting different branches of physics.
0:51:39 > 0:51:45But immediately after I was also thinking, "It's too simple."
0:51:50 > 0:51:54On the face of it, the theory looks much like the others.
0:51:55 > 0:51:59It predicts a multiverse, and at least one big bang.
0:52:01 > 0:52:05But it stands out in one crucial respect.
0:52:06 > 0:52:12It doesn't commit the scientific sin of assuming initial conditions.
0:52:12 > 0:52:16It doesn't assume an earlier collapsing universe.
0:52:18 > 0:52:22It doesn't assume pre-existing inflation.
0:52:25 > 0:52:28And it doesn't assume a primordial black hole.
0:52:32 > 0:52:37According to Mersini-Houghton, it assumes nothing at all.
0:52:37 > 0:52:40as far as I know it's one of the few theories
0:52:40 > 0:52:44where everything is derived from first principles and fundamental physics.
0:52:44 > 0:52:48Nothing has been tweaked by hand or can be changed.
0:52:48 > 0:52:51Even if I wanted to change a parameter,
0:52:51 > 0:52:54the equations would not allow me to do that.
0:52:55 > 0:53:00The other remarkable thing about the theory is that it fits with three observations,
0:53:00 > 0:53:04phenomena which have defied conventional explanation.
0:53:10 > 0:53:12There's an unexplained patch of nothing,
0:53:12 > 0:53:17the so-called void in the cosmic microwave background.
0:53:21 > 0:53:28And great swathes of galaxies have been found to be moving in the wrong direction.
0:53:28 > 0:53:34Another finding shows there's something odd about the temperature in outer space.
0:53:35 > 0:53:37According to Mersini-Houghton,
0:53:37 > 0:53:42all these effects are due to the presence of neighbouring universes,
0:53:42 > 0:53:48and are explained in precise detail by her theory.
0:53:48 > 0:53:52I really started taking the theory seriously
0:53:52 > 0:53:57only when the predictions that we derived were successfully tested.
0:53:57 > 0:54:01Three unexplained, difficult to accommodate findings,
0:54:01 > 0:54:03observational findings,
0:54:03 > 0:54:08seem to just fall beautifully together in this theory
0:54:08 > 0:54:09and hang together.
0:54:09 > 0:54:13And it's a theory that would not only explain
0:54:13 > 0:54:17the high energy big bang, but have a continuation.
0:54:17 > 0:54:22A pre-big bang and after big bang part of the story.
0:54:22 > 0:54:25So now you do know what happened before the big bang?
0:54:25 > 0:54:28I think so. Yeah, I'm starting to believe it.
0:54:45 > 0:54:49In the last ten years, cosmology has experienced a remarkable turnaround.
0:54:51 > 0:54:54From insisting that there was nothing at all before the big bang,
0:54:54 > 0:55:00most researchers now concede that there must have been something.
0:55:02 > 0:55:07But understanding what that something was and how it worked,
0:55:07 > 0:55:14means that cosmologists are having to give up many of their most prized certainties.
0:55:17 > 0:55:22Whatever the fate of the ideas which are on the table now,
0:55:22 > 0:55:26about the big bang and before the big bang,
0:55:26 > 0:55:28it's inconceivable to me
0:55:28 > 0:55:30that the universe really started at the big bang.
0:55:30 > 0:55:35Why? Because that would leave so many basic questions unanswered.
0:55:36 > 0:55:39What I certainly believe in is that
0:55:39 > 0:55:43the big bang is just a very small event in this whole history of the universe.
0:55:43 > 0:55:46And I think that itself is a big paradigm change.
0:55:46 > 0:55:49Once we start thinking about things before big bang,
0:55:49 > 0:55:51and we work on these theories,
0:55:51 > 0:55:54maybe very soon we'll find an answer to how it all started.
0:55:58 > 0:56:01My parents were Buddhists.
0:56:01 > 0:56:04In Buddhism there is no beginning, there is no end.
0:56:04 > 0:56:05There is just Nirvana.
0:56:05 > 0:56:08But as a child I also went to Sunday school,
0:56:08 > 0:56:11where we learned that there was an instant where God said,
0:56:11 > 0:56:12"Let there be light".
0:56:17 > 0:56:21So I've had these two mutually contradicting paradigms in my head.
0:56:21 > 0:56:27Well, now we can meld these two paradigms together into a pleasing whole.
0:56:27 > 0:56:29Yes, there was a genesis.
0:56:29 > 0:56:33Yes, there was a big bang, and it happens all the time.
0:56:35 > 0:56:40I'm open to almost any philosophical point of view, as long as it works,
0:56:40 > 0:56:45and I want a theory that's ultimately tested by data and confirmed
0:56:45 > 0:56:48that this is the way the world works.
0:56:52 > 0:56:58The story of cosmology is a quest for the ultimate truth,
0:56:58 > 0:57:05but one where crazy notions like the big bang sometimes turn out to be correct.
0:57:05 > 0:57:07For a while, at least.
0:57:11 > 0:57:17Its characters are men and women who defend their theories as passionately as any priest...
0:57:22 > 0:57:26..who believe it is their calling to answer questions
0:57:26 > 0:57:30that were once thought to be unknowable.
0:57:30 > 0:57:34If you are not brave enough to ask strange questions,
0:57:34 > 0:57:41if you are not brave enough to believe your own answers even if they are unbelievable,
0:57:41 > 0:57:47then, well, OK, so you live your life, but then it is not completely fulfilled.
0:57:47 > 0:57:51If you take courage to answer questions
0:57:51 > 0:57:56in not necessarily the ways which other people expect you.
0:57:56 > 0:58:00Sometimes you just end up saying stupid things.
0:58:00 > 0:58:04Sometimes you end up saying something maybe wise.
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