What Happened Before the Big Bang? Horizon


What Happened Before the Big Bang?

This episode of the science series explores a dizzying world of cosmic bounces, rips and multiple universes, and finds out what happened before the big bang.


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Transcript


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In the first few years of the new millennium,

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this starkly strange building

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emerged from the Canadian countryside.

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In it are housed some of the most extreme minds in science.

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The ideas produced within the walls of this institution,

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are intended to shed new light on science's hardest problem.

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Is there an ultimate answer?

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I don't know.

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I don't even know if the question makes sense.

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They intend to tell us once and for all where we came from

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by unravelling the deepest mysteries of the birth of the universe.

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Time did not exist before the beginning.

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Somehow, time sprang into existence.

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Now, that's a notion which we have no grasp of

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and which may be a logical contradiction.

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They are re-writing science's story of creation.

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Why is it, all of a sudden, there are

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laws of nature, and where did they come from?

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Why these laws and not other laws?

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And they've concluded that one of the 20th century's

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greatest scientific ideas might have to be thrown out.

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There is certainly not big bang. That is impossible.

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I don't believe in that at all.

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For thousands of years, science has tied to understand the mysteries of the night sky.

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It is an awe-inspiring achievement that a certain kind of ape

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has discovered that it is living on a planet,

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that the planet is flying around a star in a galaxy.

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..and that that galaxy that is just one of a vast sea of galaxies in a near-infinite universe.

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But now it seems, science is about to go one step further

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with an idea that will make previous breakthroughs in cosmology

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pale into insignificance.

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It is the grandest concept imaginable,

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yet it has its roots in an notion that we are all familiar with.

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Cause.

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and effect.

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Cause.

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Effect.

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It's a simple, yet powerful idea.

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Because one thing follows another, we can stray from the present.

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We can boldly stride into the future,

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and confidently travel back in time.

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It's this idea that allowed American astronomer Edwin Hubble to draw

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a far-reaching conclusion to what he saw in the movement of galaxies.

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The discovery of the century had to be Edwin Hubble making his Hubble diagram.

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And what he did is he just plotted distance versus velocity, or speed, of the galaxy.

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And can you imagine one day making that plot

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and you discovered things further away

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were moving faster away from you?

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And this is the famous Hubble diagram

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which told us that the universe is expanding.

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This revolutionised our view of the universe.

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Not only was there a universe out there but now there was a universe

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that was expanding and it was getting bigger and bigger with time.

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And it didn't take long for someone to figure out,

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"If it's getting bigger with time, surely it started from somewhere."

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And this really brought out the first idea

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that there was a moment of creation

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i.e. the big bang.

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I think the discovery that the universe was expanding

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was one of the most significant in science.

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It's on a similar level to Darwin's discovery of evolution.

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It tells us the universe

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wasn't always the way it is today,

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it tells us we came from something,

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something violent,

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something extraordinary.

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The big bang is an elegant answer to the biggest question that science can ever ask.

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It's startling idea.

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It gives us a sense of origin.

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And however odd the notion sounds, it's a comfort to know exactly where we came from.

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Science assures us that our universe exploded into existence

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13.7 billion years ago.

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And thanks to cause and effect, science knows what happened

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right from the very beginning of the bang itself.

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Well, almost.

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So, in the standard picture, if this is the history of our universe,

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then this is where the big bang is.

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At t = 0.

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This is when the baby was born.

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And when the universe is somewhere here.

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where this is 10 to the power of -34th of this one second.

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So we know about the universe up until 0.0000341 seconds

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before it started.

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That's a pretty small number, isn't it?

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At this point, the classical theory would fail.

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The thing is, big bang doesn't quite work.

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So much so, that people are now starting to think the unthinkable -

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that big bang wasn't the beginning at all.

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How many people think that there was something before the big bang?

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Ten years ago, this would never have happened.

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Then, there was no doubt that "before the big bang"

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made no sense. But today, the certainty has gone.

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There is no escaping the inconvenient truth

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that Hubble's graph,

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work of genius though it is,

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contains a huge problem.

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It tells us that everything we see in the universe today -

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us, trees, galaxies,

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zebras, emerged in an instant from nothing.

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And that's a problem.

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It's all effect, and no cause.

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The idea of "everything from nothing"

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is something that has occupied physicist Michio Kaku

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for much of his professional life.

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You know, the idea sounds impossible.

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preposterous. I mean, think about it - everything from nothing!

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The galaxy,

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the stars in the heavens coming from a pinpoint.

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I mean how can it be? How can it be that everything comes from nothing?

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But you know, if you think about it a while,

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it all depends on how you define "nothing".

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In Sandusky, Ohio, is Plum Brook Station.

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It is here that NASA recreates the conditions of space on Earth,

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and part of that means generating nothing.

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..in vast quantities.

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This is the biggest vacuum chamber in the world.

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Its eight-feet-thick walls are made from 2,000 tons of solid aluminium.

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It takes two days of pumping out the air,

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and another week of freezing out the remaining molecules

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to create a near-perfect vacuum.

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A cathedral-sized volume of nothing.

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When they switch this place on,

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this is as close as we can get to a state of nothingness.

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Everywhere we look we see something.

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We see atoms, we see trees, we see forests, we see water.

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but hey, right here, we can pump all the atoms out,

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and this is probably the arena out of which genesis took place.

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So if you really understand the state of nothing,

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you understand everything about the origin of the universe.

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Except, of course, it isn't quite that straightforward.

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For a start, the "nothing" created by NASA

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still has dimensions -

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this is nothing in 3-D.

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And the tests carried out within the chamber can, of course, be viewed.

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This is nothing through which light can travel.

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NASA's "nothing" has properties.

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This "nothing" is, in fact, something.

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I think there are two kinds of nothing.

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First there is what I call absolute nothing, No equations, no space,

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no time, absence of anything that the human mind can conceive of,

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just "nothing", but then I think,

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"There is the vacuum, which is nothing but the absence of matter."

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Professor Kaku's version of nothing is a perfect vacuum where,

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on the face of it, there is only energy.

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But in a perfect vacuum,

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energy sometimes transforms itself,

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temporarily and briefly, into matter.

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It is one of these tiny explosions

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that might have kept going and ended up in the big bang.

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So for me, the universe did not come from "absolute nothing",

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that is a state of no equations, no space, no time,

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it came from a pre-existing state, also a state of nothing.

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That our universe did actually come from

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this infinitesimal tiny explosion that took place,

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giving us the big bang and giving us the galaxies and stars we have today.

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For Professor Michio Kaku,

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the laws of physics did not arrive with the big bang.

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The appearance of matter did not start the clock of time.

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His interpretation of "nothing" tells him that there was, in short, a "before".

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If he's right, there's an opportunity for a cause to have an effect after all.

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At Stanford University near San Francisco, Professor Andrei Lind

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believes that the big bang itself is a flawed concept,

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but one that holds tantalising clues to the "real" story of creation.

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The idea of the big bang was a very powerful idea,

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but, er, this idea chad its own problems.

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One of the problems -

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why the universe was as big as it is now?

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The second idea - who made it expand?

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What caused this explosion?

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Big Bang was clearly a very special explosion.

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Ordinary explosions are messy.

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This one produced a universe that wasn't messy at all.

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Our universe is "smooth" -

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it looks more or less the same in every direction.

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It was an observation that required a radical explanation.

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Professor Linde was one of the cosmologists who provided it.

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The idea was that, just after matter first appeared, rather than a messy explosion,

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there was instead a massive and unprecedented growth in the size of the universe.

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The process is called inflation.

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If one assumed that there was

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this period of exponential expansion of the universe,

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in some energetic, vacuum-like state,

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then you can explain why the universe is so large,

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why our universe is so smooth at the very large scale,

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why properties of the universe in different parts

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are so similar to each other.

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All of these questions can be addressed

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if one uses inflation.

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The big bang and inflation explained everything.

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the universe began with a matter-producing explosion.

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Then, inflation sped things up and smoothed things out for a while,

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before disappearing, to leave the gently-expanding universe we see today.

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Inflation was so successful

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that Linde began to wonder if the big bang was needed at all.

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Maybe it's easier to say that there was inflation from the very beginning.

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It was not difficult from the point of view of mathematics,

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it was a difficult psychological step

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to give it up.

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Linde's masterstroke was to cut the big bang

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out of the story altogether,

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and to envisage inflation as something from which our universe emerged.

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A pre-existing condition that has been there...

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well, forever.

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You have Swiss cheese, OK?

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And in Swiss cheese, we have these bubbles of air.

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OK? So just imagine that the cheesy part of it

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is heavy vacuum and the universe expands

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and these bubbles appear inside.

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And it looks like infinite universe inside.

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So for Linde, the big bang isn't really a starting point at all

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He thinks that it's simply the end of something else.

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The universe appeared out of the cheese of what he calls "eternal inflation",

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in an area where the inflation simply ran out of steam.

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This has huge implications.

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It means that when we look into the night sky,

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we see only a tiny piece of the story of existence.

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Our universe is not alone.

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There are others,

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all co-existing within the eternally-inflating super-universe of Linde's cheese.

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And he's counted them.

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We have calculated how many really different options

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you can see on the way of your travel.

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And what did that give you?

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And that gave us the number 10 to the degree 10 to the degree

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10 to the degree 7.

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This is a huge...

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absolutely enormous number.

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But that's what we got as a result of our calculations.

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Andrei Linde is a highly-respected scientist.

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His ideas of the multiverse, odd as they seem, are now within the scientific mainstream.

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For many cosmologists, eternal inflation is in itself a reasonable explanation

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of what existed before our universe.

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But for others,

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it's utter nonsense.

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It's too arbitrary.

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You can start it one way,

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another way, you can tweak the parameters

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to get whatever observations you want.

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This is very dissatisfying.

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I basically feel we are letting down our tradition

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of theoretical physics, which is the most precise,

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predictive, powerful area of science we know,

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and we've got to do better than this.

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Professor Turok runs the Perimeter Institute for fundamental physics research near Toronto in Canada.

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And you will get...one plus two!

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It is full of men and women

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trying hard to follow their leader's urgings to "do better".

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Eternal inflation is quite a different creature than ordinary inflation.

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Here, thinking about what happened before the big bang is all part of a day's work.

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And though most people think there was something before the big bang...

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How many people think there was

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a universe before the big bang which was much like this one?

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..no-one can quite agree on what,

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or even if there was a bang at all.

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I do believe that there is no big bang, but I don't know what is on the other side for sure.

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How much would you bet? Would you bet your house?

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-Would you bet, um...

-LAUGHTER

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Param Singh is working on a theory that he hopes will shorten the odds.

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He's trying to overcome the same problem as everyone else,

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namely the rather inconvenient idea of everything emerging from nothing,

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one Thursday afternoon 13.7 billion years ago.

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But Param's ideas strike at the fundamental principles that cause all the problems in the first place.

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So if you believe the universe is expanding

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and if you look at its history,

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then the universe must have expanded from something.

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And if you look backward and backward,

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what big-bang theory tells you

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is that the universe starts expanding from nothing.

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The principle mathematical objection is that, as the clock is wound back,

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and Hubble's zero hour is approached,

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all the stuff of the universe is crammed into a smaller and smaller space.

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Eventually, that space will become infinitely small.

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And in mathematics, invoking infinity is the same as giving up.

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Or cheating.

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Even if the mathematical laws would not have broken down at this point,

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even then it's philosophically very incomplete,

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like, how can something just originate from nothing?

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And that is what the theory has to explain.

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It's Param's job to understand how the unimaginably large emerged from the infinitesimally small.

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But it's not just philosophy and infinity that stands in his way.

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If you look at our universe which is at large scales, the mathematics that we know

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from Einstein's' theory very well describes most of the phenomena -

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all of the phenomena. Like this ball which I throw up - it comes back.

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But if I want to describe what is inside this ball,

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the atomic structure of the ball,

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or how the molecules are made and how atoms are made,

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what are their fundamental constituents,

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then I don't use classical gravity, I use a completely different physics called quantum mechanics.

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If I look at the universe, and I ask the question, I want to describe how it came from nothing,

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what was its nature when it was very small,

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then I have to use both the classical gravity and quantum mechanics and they don't talk to each other.

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What I need is a new theory, a new mathematics.

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And that is the biggest problem to find.

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Param Singh has been working on a way to combine the two systems.

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A scheme that works in the very big AND the very small.

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What he's found is that the maths predicts a very peculiar phenomenon.

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What we find is, that gravitational force,

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which is attractive, becomes repulsive when the universe is very small.

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That is predicted by the mathematics,

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the new mathematics which we obtain by the marriage of quantum mechanics and Einstein's gravity.

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It is a completely different paradigm now.

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The problem of the big-bang infinities

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are swept away by the new "repulsive" gravity.

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The point of "everything in nothing"

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is never reached.

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The maths is here,

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so this is one of the equations which took a couple of years to derive

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and the part in orange

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is the one that is predicted by Einstein's theory

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and the part in the white

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is the corrections which come from quantum gravity.

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So if you look at this orange part,

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this orange part tells you that if you look at the universe,

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which is becoming smaller and smaller as you approach big bang,

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the left-hand side and the right-hand side,

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they both become infinity.

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And we know that whenever we encounter infinity in mathematics,

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something has gone terribly wrong.

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So what quantum gravity gives us is this expression,

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which ensures that as we approach the big bang,

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when the universe is becoming smaller and smaller, both sides become zero,

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and after that, the universe starts expanding again

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on the other direction and the same laws remain valid.

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-Problem solved.

-Problem solved.

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In Param Singh's scheme, instead of emerging from nothing,

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our universe owes its existence to a previous one

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that had the misfortune to collapse in on itself,

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then, thanks to some clever maths,

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rebounded to become what we see today.

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So the big bang was not a bang at all.

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It was, rather, a big bounce.

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It's a surprising thing, a bouncing universe, but in nature,

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if you look around us, there are lots of cycles, always happening,

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like we have seasons,

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we have even the motion of planets around sun.

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In fact, nature tries to prefer things were just cyclic in a way.

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But if we look at the whole lifespan of the age of the universe,

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which is billions of years, then maybe these cycles or the bounces, may not at all be surprising,

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and these are just the cycles of weather,

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in a way, for the universe,

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of going through contraction and expansion

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and contraction and expansion and so on.

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Of course, it might all be nothing more than a fantasy world of maths and little else.

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And there's always the nagging question

0:24:270:24:30

of what started the infinite bouncing in the first place.

0:24:300:24:34

Well, that's the most important question and I don't know the answer to that.

0:24:340:24:39

Maybe very soon we'll find an answer to how it all started.

0:24:390:24:43

-But it wasn't big bang?

-It was certainly not big bang,

0:24:430:24:47

that is impossible, I don't believe in that at all.

0:24:470:24:50

Down the corridor from Param Singh is the office of Lee Smolin.

0:25:010:25:07

But Professor Smolin rarely uses it.

0:25:080:25:10

He's more usually to be found doing his thinking elsewhere.

0:25:100:25:15

For him, the very idea of "everything from nothing" -

0:25:200:25:24

the so-called "singularity" - points to a lack of understanding.

0:25:240:25:28

I strongly, strongly believe

0:25:320:25:37

that there was a period before the big bang,

0:25:370:25:39

that the singularity was eliminated.

0:25:390:25:42

To me, the singularity is not an indication

0:25:420:25:45

that there was a first moment of time -

0:25:450:25:47

it's an indication

0:25:470:25:49

that general relativity is an incomplete theory.

0:25:490:25:52

It's general relativity shouting at us,

0:25:520:25:55

screaming at us, "I am not the end."

0:25:550:25:57

There is more to understand.

0:25:570:25:59

In his bid to further his own understanding of the cosmology,

0:26:030:26:09

Professor Smolin has cast his scientific net wide.

0:26:090:26:14

And, though he shares a lot of ground with Param Singh,

0:26:140:26:17

and even Andrei Linde,

0:26:170:26:20

his interpretation of what happened before the big bang

0:26:200:26:24

owes more to Charles Darwin than to Albert Einstein.

0:26:240:26:28

The idea works by analogy to how biology works.

0:26:310:26:36

It says that the universe has an ancestor,

0:26:360:26:39

which is another universe.

0:26:390:26:41

How is the universe born from the ancestor?

0:26:410:26:46

According to this hypothesis,

0:26:460:26:48

the universe is born inside of a black hole.

0:26:480:26:52

A black hole is a star which collapses,

0:26:550:26:59

where everything becomes infinite and time stops.

0:26:590:27:07

There is a bounce inside of every black hole.

0:27:070:27:10

The material contracts

0:27:110:27:13

and contracts and contracts again and then begins to expand again.

0:27:130:27:17

And that is the big bang which initiates a new region of the universe.

0:27:190:27:25

Smolin's natural selection idea proposes that for a universe to prosper, it must reproduce.

0:27:270:27:34

And for that to happen it must contain black holes,

0:27:340:27:38

that according to Smolin, spawn offspring universes.

0:27:380:27:43

Before the big bang was another universe much like our own.

0:27:440:27:50

In that universe there was a big cloud of gas and dust.

0:27:500:27:56

It collapsed to form a big massive star,

0:27:560:28:00

that star exploded, it left behind a black hole,

0:28:000:28:05

and in that black hole there was a region,

0:28:050:28:08

if you were misfortunate enough to fall in,

0:28:080:28:11

you would find it becoming denser and denser and denser.

0:28:110:28:14

You wouldn't survive this, but let's imagine you did.

0:28:140:28:17

And all of a sudden,

0:28:170:28:18

it would explode again and that would be our big bang.

0:28:180:28:22

It's a beguilingly simple, and controversial combination of two

0:28:250:28:30

of the greatest scientific breakthroughs of the modern age.

0:28:300:28:34

I think that the theoretical evidence is moving towards this idea.

0:28:340:28:41

And that's good.

0:28:410:28:43

That gives me some confidence for the future.

0:28:430:28:46

Professor Smolin is convinced that the big bang was not the beginning.

0:28:470:28:53

And until his theory of cosmological natural selection is conclusively proven, he's committed

0:28:530:29:00

to pursuing all avenues that might provide answers to what came before.

0:29:000:29:06

I think the only way to keep going in this business is to go

0:29:060:29:11

under the assumption that tomorrow's idea will be the best one so far.

0:29:110:29:15

So I'm trying!

0:29:150:29:16

Ten years ago, the only idea in cosmology was the unexplained big bang followed by inflation.

0:29:220:29:29

"Pre-big bang" was only talked about behind closed doors by radicals.

0:29:310:29:37

But today it's almost mainstream.

0:29:390:29:42

Yeah, we just have to replace this with this.

0:29:450:29:49

Back at the Perimeter Institute,

0:29:490:29:51

there are any number of strange ideas about how our universe was born.

0:29:510:29:58

And perhaps the strangest of all comes from the Institute's director, Professor Neil Turok.

0:29:580:30:05

There are essentially two possibilities at the beginning.

0:30:070:30:10

Either time did not exist before the beginning,

0:30:100:30:14

somehow time sprang into existence.

0:30:140:30:17

Now that's a notion which we have no grasp of

0:30:190:30:23

and which may be a logical contradiction.

0:30:230:30:28

The other possibility is that this event which initiated our universe

0:30:280:30:34

was a violent event in a pre-existing universe.

0:30:340:30:37

Professor Turok and his colleagues

0:30:390:30:41

have come up with a model that assumes a complex version of existence,

0:30:410:30:47

requiring ten spatial dimensions, plus time. Simple(!)

0:30:470:30:52

What is present in these models, the picture of the world in these models,

0:30:520:30:56

is that we live on an extended object called the brane.

0:30:560:31:01

And a brane, it's B-R-A-N-E, short for membrane.

0:31:010:31:05

But it's a membrane which is three-dimensional.

0:31:090:31:12

All of space that we live in is part of this brane.

0:31:190:31:22

And within these models you have to have at least two of these branes.

0:31:260:31:30

You can't have only one, there have to be at least two.

0:31:300:31:34

And they are separated by a little gap along a fourth dimension of space.

0:31:340:31:40

It's not one of our existing dimensions.

0:31:400:31:43

And basically within these models, these two branes can collide.

0:31:430:31:48

When they collide, they remain extended.

0:31:510:31:54

It's not all of space shrinking to a point.

0:31:540:31:57

They fill with a density of plasma and matter, but it's finite.

0:31:570:32:01

Everything is a definite number,

0:32:010:32:04

which you can calculate, and which you can then

0:32:040:32:09

describe using definite mathematical laws,

0:32:090:32:13

and so that's the essential picture of the big bang in our model.

0:32:130:32:17

And I think it's becoming a real alternative to the conventional picture

0:32:180:32:24

that everything was created at the big bang.

0:32:240:32:28

For many cosmologists, this is mathematical sleight of hand,

0:32:280:32:34

and an unwelcome distraction to the serious business of improving on the tried and tested.

0:32:340:32:40

What happens is that the authors

0:32:400:32:42

are producing one version of the theory after another.

0:32:420:32:45

Usually the lifetime of their ideas is about one year,

0:32:450:32:49

after which it is replaced by the new set of ideas,

0:32:490:32:52

then by another set of ideas, then still by another set of ideas.

0:32:520:32:55

Not because they want to replace it,

0:32:550:32:58

but because the previous versions were disproved

0:32:580:33:01

by investigation of other people.

0:33:010:33:03

So that is something which unless the whole line of research

0:33:030:33:09

and claims and statements, will become more accurate.

0:33:090:33:14

This is something which undermines the whole idea.

0:33:140:33:17

So far just about every prediction made by inflationary theory

0:33:210:33:25

has checked out in many, many observations.

0:33:250:33:29

So it's not surprising that people like Andrei Linde are sometimes irritated

0:33:290:33:33

by what they sees as speculative mathematical attacks on inflation.

0:33:330:33:40

But it's not quite a done deal.

0:33:400:33:43

And while there is any doubt, the likes of Neil Turok feel

0:33:440:33:48

that it is their duty to point out where those doubts lie.

0:33:480:33:51

They are basing their theory on shaky foundations.

0:33:510:33:58

They cannot explain what happens before inflation.

0:33:580:34:02

And I think they've got themselves into a whole host of puzzles

0:34:020:34:08

to do with eternal inflation, and in a sense,

0:34:080:34:11

not being able to predict anything.

0:34:110:34:13

So I feel that we ARE being constructive.

0:34:130:34:17

We're putting forward an alternative, one which can be proven wrong,

0:34:170:34:20

and one which I think

0:34:200:34:24

may in time become much more complete and satisfying

0:34:240:34:29

than the theory of inflation.

0:34:290:34:31

Ever since the idea of the big bang, people have wondered what caused it.

0:34:470:34:53

What made everything apparently spring un-bidden from nothing?

0:34:530:34:56

Might it be that Neil Turok's right,

0:35:050:35:08

that the miracle was due to colliding branes in another dimension?

0:35:080:35:12

Or perhaps Lee Smolin has the answer.

0:35:140:35:16

Our big bang was simply the other side of a black hole in a galaxy far, far away.

0:35:160:35:24

Maybe it would be best, like Michio Kaku, to stop thinking of nothing as nothing,

0:35:260:35:32

but rather as just absence of stuff,

0:35:320:35:35

and to imagine bubbles of matter forming in a high-energy vacuum.

0:35:350:35:42

Is Param Singh correct?

0:35:420:35:44

No big bang at all,

0:35:440:35:46

just the big bounce,

0:35:460:35:47

again, and again, and again.

0:35:470:35:53

Or should we subscribe to Andrei Linde's Swiss cheese model,

0:35:560:36:01

and redefine the big bang as simply the inflationary energy of a mega-verse dying out?

0:36:010:36:07

Ten to the power ten to the power ten to the power seven times.

0:36:070:36:14

All of these ideas stray from the standard model of cosmology,

0:36:190:36:23

which holds that everything emerged from nothing at the point of the big bang.

0:36:230:36:29

And they would be easier to dismiss as the half-baked musings of the lunatic fringe,

0:36:290:36:34

were it not for the fact that some of the very people who constructed

0:36:340:36:39

the everything from nothing big bang model are themselves starting to dismantle it.

0:36:390:36:46

For many years, Professor Sir Roger Penrose spent much of his time

0:36:530:36:57

dismissing the very idea of "before the big bang" as a complete non-starter.

0:36:570:37:04

If people would ask me what happened before the big bang, my normal answer would be to say,

0:37:050:37:10

"The word before. What does that mean?"

0:37:100:37:13

Well, that's a sort of temporal concept.

0:37:130:37:16

And if the big bang was a singularity in space-time,

0:37:160:37:20

that means the very notion of time loses its meaning at this event,

0:37:200:37:25

this so-called big bang.

0:37:250:37:28

So if the notion of time loses its meaning,

0:37:280:37:30

the very notion of before loses its meaning.

0:37:300:37:32

So we would tend to say

0:37:320:37:33

it's a meaningless question to ask for before,

0:37:330:37:36

there wasn't a before, that's the wrong kind of notion.

0:37:360:37:39

And I would have perhaps gone along with this point of view,

0:37:390:37:42

until I've had some different ideas more recently.

0:37:420:37:45

Professor Penrose has concluded that to understand the origin of the big bang,

0:37:470:37:54

science needs to study the end of the universe.

0:37:540:37:57

The present picture of the universe is that it starts with a big bang,

0:37:580:38:03

and it ends with an indefinitely expanding,

0:38:030:38:06

exponentially expanding universe,

0:38:060:38:08

where in the remote future it cools off,

0:38:080:38:10

and there's not much left except photons.

0:38:100:38:12

Now what I'm saying is that in this remote future,

0:38:190:38:22

the photons have no way of keeping time and they don't have any mass.

0:38:220:38:26

You need mass to make a clock, and you have to have a clock to measure the scale of the universe.

0:38:280:38:34

So the universe loses track of how big it is.

0:38:340:38:37

And this very expanded universe

0:38:370:38:39

becomes equivalent to a big bang of another one.

0:38:390:38:43

So I'm saying that this, what we think of our present universe

0:38:430:38:47

is but one eon of a succession of eons

0:38:470:38:50

where this remotely expanding universe of each becomes the big bang of the next.

0:38:500:38:56

So small and big become completely equivalent.

0:38:590:39:03

If Professor Penrose is right,

0:39:090:39:11

our universe's expansion means that all its mass will eventually be converted to energy.

0:39:110:39:18

When that happens, conventional ideas of time and size disappear.

0:39:180:39:23

The contention is that because of this,

0:39:260:39:29

a nearly infinitely large universe

0:39:290:39:31

could just as well be the infinitely small starting point for the next one.

0:39:310:39:36

A cyclic system with a before and an after.

0:39:380:39:43

It's quite a volte-face for a man who was until five years ago a pre-big bang denier.

0:39:450:39:53

Let me say that a change of mind is not something unpleasant, I find,

0:39:530:39:57

it's something exhilarating.

0:39:570:39:58

Because you get stuck in a rut and that's what I find, you know,

0:39:580:40:02

you're thinking about certain things,

0:40:020:40:04

and after a while you think you're stuck into this rut.

0:40:040:40:07

And a change of mind, you think, "Ah, why didn't I think of it like that?"

0:40:070:40:12

That's extraordinarily exhilarating.

0:40:120:40:14

It is a huge turnaround.

0:40:170:40:20

For 50 years, the big bang,

0:40:200:40:23

stating that everything including space and time emerged from nothing, has been scientific fact.

0:40:230:40:30

And though what Professor Penrose and the others are suggesting is revolutionary,

0:40:320:40:36

it's worth remembering that revolutions in cosmology have happened before.

0:40:360:40:42

500 years ago, anyone suggesting that the earth orbited the sun would have been ridiculed,

0:40:440:40:49

and then arrested.

0:40:490:40:52

But from Copernicus to Galileo...

0:40:560:40:58

..from Hubble to Hawking,

0:41:020:41:04

the emerging cosmology has opened our eyes in stages to a bigger, truer picture.

0:41:040:41:12

What is now being proposed is nothing less than the promise of the biggest picture yet.

0:41:120:41:20

Probably the biggest picture possible.

0:41:200:41:23

But in science, ideas are just ideas until they are confirmed

0:41:250:41:30

or denied by observations.

0:41:300:41:34

And because the pre big bang ideas are so radical, the race to back them up is intense.

0:41:340:41:41

In rural England, there's a project under way that could seriously undermine inflation,

0:41:420:41:48

the mainstay of the current cosmology.

0:41:480:41:51

What we're doing today is building part of the world's biggest radio telescope.

0:41:510:41:57

Which will allow us to look back

0:41:570:41:59

to about a billion years after the big bang.

0:41:590:42:02

So we'll get a glimpse of the universe in its adolescent years.

0:42:020:42:08

Professor Bob Nichol is part of a team of academics constructing a new generation of radio telescope.

0:42:130:42:20

It's called the Low Frequency Array - LOFAR.

0:42:240:42:29

And though it lacks the iconic beauty of the 25 metre dish whose site it shares...

0:42:290:42:35

..its scientific ambition more than makes up for the aesthetic disappointment.

0:42:380:42:43

One of the foundations of cosmology is inflation.

0:42:460:42:50

And one of the great things about inflation is that it says on the largest scales in the universe,

0:42:500:42:56

the universe should be random,

0:42:560:42:58

and the galaxies and the matter should be distributed randomly.

0:42:580:43:02

So what we can do with this telescope is check that.

0:43:020:43:05

And if we don't see it, if it's not random,

0:43:050:43:08

then that's going to set the cat amongst the pigeons,

0:43:080:43:12

and someone's going to have to come up with a better idea

0:43:120:43:15

for what could have caused that non-randomness in the universe.

0:43:150:43:19

-What do you think?

-Ah, I think... I'm not paid to think.

0:43:190:43:26

I'm paid to make the observations.

0:43:260:43:29

I would love it, I would love it to be non-random.

0:43:290:43:32

That would just be fantastic, right? It would really just give us something new to think about.

0:43:320:43:38

And that's what being a scientist's all about.

0:43:380:43:42

If LOFAR removes inflation,

0:43:420:43:44

the whole of the standard model of cosmology would be called into question.

0:43:440:43:49

But if it confirms inflation, it will not only support the standard model,

0:43:490:43:54

it will leave most of the competing theories intact as well.

0:43:540:43:59

To settle those arguments, the ambition is nothing less than to observe the big bang itself.

0:43:590:44:07

Of course, we're 13.7 billion years too late to witness the actual event.

0:44:130:44:18

But in a quiet corner of Louisiana, they're looking for the next best thing.

0:44:180:44:24

They're hunting for gravity waves.

0:44:270:44:31

But gravity waves are such slight and shy beasts that finding them has not been easy,

0:44:310:44:38

even in the relative peace of rural Louisiana.

0:44:380:44:42

This is LIGO,

0:44:430:44:47

the Laser Interferometer Gravitational Wave Observatory...

0:44:470:44:51

..where Joe Giaimi is sniffing out the reluctant gravity waves with laser beams and mirrors.

0:44:530:45:01

This concrete enclosure

0:45:010:45:03

protects the stainless steel vacuum tube that encloses our beam,

0:45:030:45:09

and it goes on for the next four kilometres.

0:45:090:45:12

How come it has to be so long?

0:45:120:45:14

Well, the way gravitational waves work,

0:45:140:45:17

the longer the distance you measure,

0:45:170:45:20

the larger the change in that length you see.

0:45:200:45:24

And four kilometres was chosen because we could afford it, and we could find a plot of land that big.

0:45:250:45:31

A gravity wave is thought to be produced when cataclysmic events take place,

0:45:340:45:40

like the big bang.

0:45:400:45:42

OK, let's go.

0:45:460:45:48

The gravity waves that are theoretically produced by such an event

0:45:480:45:53

are thought to warp the very fabric of space and time.

0:45:530:45:58

And it's this warping that Joe is hoping to measure with LIGO.

0:45:580:46:04

LIGO generates a laser beam which is split into two

0:46:040:46:08

and then reflected off mirrors at the end of each 4km tunnel.

0:46:080:46:12

When the beams arrive back at the start of their journey,

0:46:130:46:16

they should still be in sync with each other.

0:46:160:46:19

If they're not, it might be that a gravity wave

0:46:190:46:22

has temporarily changed the relative lengths of LIGO's arms.

0:46:220:46:27

A bit.

0:46:270:46:28

The difference between those two lengths,

0:46:300:46:33

we're sensitive to that by less than 10 in the minus 18 metres.

0:46:330:46:37

So if this arm length were to change with respect to that arm length

0:46:370:46:42

bigger than that, bigger than 10 in the minus 18 metres, we could see it.

0:46:420:46:46

And what does that equate to?

0:46:460:46:48

10 in the minus 18 metres is 1/1,000 the diameter of a proton,

0:46:480:46:53

or 1/1,000 the diameter of the smallest atomic nucleus,

0:46:530:46:57

the nucleus of a hydrogen atom.

0:46:570:46:59

-And you can measure that?

-Yes.

0:46:590:47:02

24 hours a day, 7 days a week,

0:47:060:47:10

a patient band of physicists watch over the signal in shifts.

0:47:100:47:14

So while we're taking data, we always have two people in the control room.

0:47:160:47:20

TRAIN WHISTLE

0:47:200:47:23

Can I just stop there? What was train whistle?

0:47:230:47:25

OK, so... All right.

0:47:250:47:28

When we lose lock, which is what just happened,

0:47:280:47:34

that little train whistle goes off, because usually when we lose lock it's because of a train.

0:47:340:47:41

TRAIN WHISTLE

0:47:410:47:43

With tolerances so fine, measurement can be affected by almost anything that moves on earth.

0:47:450:47:52

Freight trains passing five miles away...

0:47:520:47:57

TRAIN WHISTLE

0:47:570:47:59

..means that operations cease.

0:47:590:48:02

So if we...

0:48:030:48:05

ALARM RINGS

0:48:050:48:08

Tornado warning.

0:48:080:48:09

Though the technology is in its infancy, its potential is huge.

0:48:140:48:20

LIGO is, in short, a prototype big bang detector.

0:48:200:48:25

And once the concept is proved on earth,

0:48:370:48:40

another interferometer will be built in space,

0:48:400:48:43

where arms three million miles long

0:48:430:48:47

will intercept the remains of the gravity waves theoretically produced at the beginning of time.

0:48:470:48:54

And it could go even further.

0:48:560:48:58

It could be that hidden in the signature of that first wave

0:48:580:49:02

is contained evidence of previous big bangs.

0:49:020:49:06

Good news perhaps for Param Singh and Roger Penrose when the satellites eventually fly.

0:49:080:49:15

It is the holy grail of science to turn theory into fact with concrete observations,

0:49:230:49:29

and for pre-big bang ideas, the evidence is proving frustratingly elusive.

0:49:290:49:36

But there is a scientist who believes that her idea

0:49:360:49:39

has actually has been backed up by not one, but three observations already.

0:49:390:49:46

Laura Mersini-Houghton's radical theory materialised, quite suddenly, in 2006.

0:49:460:49:52

I was teaching early at 8am in the morning.

0:49:550:49:57

And it was one of those large classes with about 100 students.

0:49:570:50:02

I'm not an early riser, so I wasn't happy about it.

0:50:020:50:06

However, I did manage to come and teach, and was done by 9am.

0:50:060:50:11

So I thought, "I deserve a coffee.

0:50:110:50:15

"Time for a coffee to wake up and plan the rest of the day."

0:50:150:50:19

Of course I'd been thinking about the big questions of cosmology.

0:50:230:50:27

Why did we start with this big bang and what was there before?

0:50:270:50:33

And suddenly this idea comes.

0:50:380:50:43

It was an idea that emerged from the fact that it's possible

0:50:440:50:48

to represent the entire universe not as an object,

0:50:480:50:52

but mathematically, as a wave.

0:50:520:50:57

Dr Mersini-Houghton's idea was to manipulate the mechanics of that waveform

0:50:570:51:02

with a branch of mathematics called string theory.

0:51:020:51:07

It seemed to provide an elegant solution as to why our universe emerged in the first place.

0:51:070:51:14

when you do that, and you calculate how that wave form evolves,

0:51:140:51:18

you do end up with the high energy big bang.

0:51:180:51:22

It seemed such a simple idea that in one hand I was very excited about it,

0:51:260:51:32

at the simplicity of the idea, and the fact that it gave a very coherent picture

0:51:320:51:36

of connecting different branches of physics.

0:51:360:51:39

But immediately after I was also thinking, "It's too simple."

0:51:390:51:45

On the face of it, the theory looks much like the others.

0:51:500:51:54

It predicts a multiverse, and at least one big bang.

0:51:550:51:59

But it stands out in one crucial respect.

0:52:010:52:05

It doesn't commit the scientific sin of assuming initial conditions.

0:52:060:52:12

It doesn't assume an earlier collapsing universe.

0:52:120:52:16

It doesn't assume pre-existing inflation.

0:52:180:52:22

And it doesn't assume a primordial black hole.

0:52:250:52:28

According to Mersini-Houghton, it assumes nothing at all.

0:52:320:52:37

as far as I know it's one of the few theories

0:52:370:52:40

where everything is derived from first principles and fundamental physics.

0:52:400:52:44

Nothing has been tweaked by hand or can be changed.

0:52:440:52:48

Even if I wanted to change a parameter,

0:52:480:52:51

the equations would not allow me to do that.

0:52:510:52:54

The other remarkable thing about the theory is that it fits with three observations,

0:52:550:53:00

phenomena which have defied conventional explanation.

0:53:000:53:04

There's an unexplained patch of nothing,

0:53:100:53:12

the so-called void in the cosmic microwave background.

0:53:120:53:17

And great swathes of galaxies have been found to be moving in the wrong direction.

0:53:210:53:28

Another finding shows there's something odd about the temperature in outer space.

0:53:280:53:34

According to Mersini-Houghton,

0:53:350:53:37

all these effects are due to the presence of neighbouring universes,

0:53:370:53:42

and are explained in precise detail by her theory.

0:53:420:53:48

I really started taking the theory seriously

0:53:480:53:52

only when the predictions that we derived were successfully tested.

0:53:520:53:57

Three unexplained, difficult to accommodate findings,

0:53:570:54:01

observational findings,

0:54:010:54:03

seem to just fall beautifully together in this theory

0:54:030:54:08

and hang together.

0:54:080:54:09

And it's a theory that would not only explain

0:54:090:54:13

the high energy big bang, but have a continuation.

0:54:130:54:17

A pre-big bang and after big bang part of the story.

0:54:170:54:22

So now you do know what happened before the big bang?

0:54:220:54:25

I think so. Yeah, I'm starting to believe it.

0:54:250:54:28

In the last ten years, cosmology has experienced a remarkable turnaround.

0:54:450:54:49

From insisting that there was nothing at all before the big bang,

0:54:510:54:54

most researchers now concede that there must have been something.

0:54:540:55:00

But understanding what that something was and how it worked,

0:55:020:55:07

means that cosmologists are having to give up many of their most prized certainties.

0:55:070:55:14

Whatever the fate of the ideas which are on the table now,

0:55:170:55:22

about the big bang and before the big bang,

0:55:220:55:26

it's inconceivable to me

0:55:260:55:28

that the universe really started at the big bang.

0:55:280:55:30

Why? Because that would leave so many basic questions unanswered.

0:55:300:55:35

What I certainly believe in is that

0:55:360:55:39

the big bang is just a very small event in this whole history of the universe.

0:55:390:55:43

And I think that itself is a big paradigm change.

0:55:430:55:46

Once we start thinking about things before big bang,

0:55:460:55:49

and we work on these theories,

0:55:490:55:51

maybe very soon we'll find an answer to how it all started.

0:55:510:55:54

My parents were Buddhists.

0:55:580:56:01

In Buddhism there is no beginning, there is no end.

0:56:010:56:04

There is just Nirvana.

0:56:040:56:05

But as a child I also went to Sunday school,

0:56:050:56:08

where we learned that there was an instant where God said,

0:56:080:56:11

"Let there be light".

0:56:110:56:12

So I've had these two mutually contradicting paradigms in my head.

0:56:170:56:21

Well, now we can meld these two paradigms together into a pleasing whole.

0:56:210:56:27

Yes, there was a genesis.

0:56:270:56:29

Yes, there was a big bang, and it happens all the time.

0:56:290:56:33

I'm open to almost any philosophical point of view, as long as it works,

0:56:350:56:40

and I want a theory that's ultimately tested by data and confirmed

0:56:400:56:45

that this is the way the world works.

0:56:450:56:48

The story of cosmology is a quest for the ultimate truth,

0:56:520:56:58

but one where crazy notions like the big bang sometimes turn out to be correct.

0:56:580:57:05

For a while, at least.

0:57:050:57:07

Its characters are men and women who defend their theories as passionately as any priest...

0:57:110:57:17

..who believe it is their calling to answer questions

0:57:220:57:26

that were once thought to be unknowable.

0:57:260:57:30

If you are not brave enough to ask strange questions,

0:57:300:57:34

if you are not brave enough to believe your own answers even if they are unbelievable,

0:57:340:57:41

then, well, OK, so you live your life, but then it is not completely fulfilled.

0:57:410:57:47

If you take courage to answer questions

0:57:470:57:51

in not necessarily the ways which other people expect you.

0:57:510:57:56

Sometimes you just end up saying stupid things.

0:57:560:58:00

Sometimes you end up saying something maybe wise.

0:58:000:58:04

Subtitles by Red Bee Media Ltd

0:58:270:58:30

E-mail [email protected]

0:58:300:58:33

They are the biggest questions that science can possibly ask: where did everything in our universe come from? How did it all begin? For nearly a hundred years, we thought we had the answer - a big bang some 14 billion years ago.

But now some scientists believe that was not really the beginning. Our universe may have had a life before this violent moment of creation.

Horizon takes the ultimate trip into the unknown to explore a dizzying world of cosmic bounces, rips and multiple universes, and finds out what happened before the big bang.


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