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(tense music)

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Scientists are brushing up upon age old questions

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that used to be the purview solely of theologians.

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Last century, a radical idea about the origin

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of everything was born.

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(tense music)

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It would become the most famous theory in all of science.

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Fred Hoyle, in rather derogatory way,

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described it as a big bang.

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As the big bang theory evolved,

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it made predictions that were only confirmed by accident.

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This radiation was discovered using this radio antenna

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that wasn't even looking for it.

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What was coming out of this thing

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had to come from somewhere.

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Had science discovered the moment of creation?

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We're looking at the infant pictures of the baby universe.

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But the big bang theory had its challenges.

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There were several problems

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that could not be explained without conspiracies.

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Cosmologists were forced to propose

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a mind-blowing scenario to fix the difficulties.

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I wake up my wife and I said,

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"I think that I know how the universe was born."

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They claimed that the universe expanded

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by trillions of times in a tiny amount of time.

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(exciting music)

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An idea called inflation.

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It took the observable universe

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and flung it apart so fast that space itself expanded faster

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than the speed of light.

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(exciting music)

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But could this be true

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or was there a flaw in the whole idea

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of the big bang itself?

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There should be a telltale signature all over the sky.

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An Intrepid team of scientists built

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a telescope in one of the most inhospitable places on Earth

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looking for the answer.

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(exciting music)

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It could be one of the greatest experiments of all time.

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But the team would face intense challenges

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and controversy as they battle

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to answer the greatest scientific mystery of them all.

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(exciting music)

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So is the big bang right?

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(exciting music)

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(tense music)

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Wondering where the universe from

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is the biggest question anyone can ask.

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(tense music)

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All the billions of galaxies,

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the untold trillions of stars and planets stretching out

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over unimaginable distances.

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What could possibly have made them?

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(tense music)

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For some, the question itself was irrelevant

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because the universe never had a beginning.

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It had just always been.

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Well our lifespans as humans are very short compared

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to the age of the universe.

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So during our lifetimes the universe

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doesn't appear to do very much.

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If you couple that with people's limited ability

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to observe distant objects,

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the universe did appear very static.

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But for others,

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a moment of creation better fitted their beliefs.

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There was a persistent belief that the universe

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must have been creative as we see it,

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and generally that was attributed to God.

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(gentle music)

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Yet, other religions believed

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that the universe might be an everlasting cycle

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of birth and death.

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These ideas that humans have had

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about whether there's a beginning to everything

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or something that's more cyclical, that is everlasting,

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that didn't have a beginning, that didn't have an end.

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These are things that have absolutely reflected now

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in the questions that we're asking

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now that we actually have data and we kind of doing this

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from a scientific point of view,

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not a religious point of view.

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Most scientists at the start

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of the 20th century thought the universe was static

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and had always been.

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(gentle music)

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But in 1915 preconceptions about the origins

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of the universe would be challenged

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when Albert Einstein published a paper.

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He came up with this beautiful theory

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of general relativity, which tells us how the whole

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of space time and should behave.

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It tells us that if you put mass into it,

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a bit like throwing a ball onto a rubber sheet,

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it deforms space.

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At its core, general relativity said

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that neither space nor time are rigid,

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there continuously distorted by matter.

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But Einstein was troubled by the implications

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of this on a cosmic scale.

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(gentle music)

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He came to realize that his new theory of relativity said

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that space actually should be changing.

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If you just put masses into space,

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the gravity of them should actually try and pull

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the space between them back together

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and should actually shrink space.

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But Einstein hated this idea.

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Einstein thought that the universe was static.

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And so he came up with this thing

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that he called the cosmological constant.

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So Einstein's cosmological constant is a kind

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of a fudge factor that he inserted into his equations.

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And he did this really on just on grounds of prejudice.

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You know, towering genius that he was,

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he somehow felt compelled to fix his equations

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to prevent the universe from expanding or contracting.

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In 1922

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a Soviet scientist called Alexander Friedmann

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began corresponding with Einstein.

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He was sort of inspired by Einstein's new theory

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of relativity and tried to apply them to the whole universe.

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And, you know, he quickly realized,

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as Einstein had, that the natural behavior

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of such a universe was to expand or contract.

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And that being perfectly stable was a kind

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of vanishingly, unlikely knife-edge point

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between those two possibilities.

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He said, depending on the kind of initial conditions,

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depending on how you started things off,

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space could be growing.

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But whatever it is, it shouldn't be static.

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It shouldn't be unchanging.

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And so he wrote a couple of scientific papers,

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but Einstein didn't like it.

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(tense music)

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It wasn't long

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before others would challenge Einstein's position.

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Working independently of Friedmann,

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was mathematician and priest George Lemaitre.

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Lemaitre was a very remarkable man.

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He had a distinguished war career.

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He was awarded the Croix de guerre by the king of Belgium

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for his service in the First World War.

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(tense music)

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A few years after Friedmann, he took a step further.

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He said, well, if the universe is indeed growing,

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then it must have come from somewhere.

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Must have had some beginning.

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He called it a cosmic egg.

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Lemaitre was the first to suggest

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that the beginning of the universe would

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also be the beginning of time.

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He called the beginning of the universe,

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"a day without a yesterday."

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Einstein when hearing about this for the first time,

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called Lemaitre's math,

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"elegant, but his physics atrocious."

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But Lemaitre had an ace of his sleeve.

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He so figured out what we should expect

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to see around us if the universe were in fact growing.

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And so we should see galaxies moving away from us

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and the ones that are further from our Milky Way,

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should recede from us faster than the ones close by.

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In a paper published in 1927,

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Lemaitre had given a prediction

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of how fast the expansion might be,

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depending on how far away we look.

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Well, this is where the experimentalist comes in

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and it always pays to look

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and let the universe tell us what it thinks.

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(upbeat music)

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And Lemaitre matter was already acquainted

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with one of the world's greatest astronomers,

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who was studying the most distant parts

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of the visible universe.

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(upbeat music)

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So Edwin Hubble studied the motion of galaxies

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and all the galaxies that he looked around at

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were all receding from us.

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And that was exactly the kind of prediction

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that Lemaitre would make,

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that the universe would be expanding.

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(upbeat music)

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In 1929 Edwin Hubble published his results

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that concurred with Lemaitre's predictions,

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the further away the galaxies he observed were,

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the faster they were moving from us.

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He calculated that the most distant galaxies

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were moving away at thousands of kilometers per second.

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Einstein, in fact, visited Edwin Hubble

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and his telescope here in Pasadena

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and came to the conclusion that putting in

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this cosmological constant was a mistake

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and accepted the idea that perhaps, this was possible.

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The universe is actually a dynamic place,

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expanding from a beginning time.

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It was rapidly proposed what's going on.

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It's not that there was an explosion centered on our galaxy.

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It's just that the entire fabric

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of space itself is expanding.

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If you think of such a picture,

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a kind of expanding grid

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with the galaxies on the grid points,

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it turns out that every point,

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as it looks out to other points,

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sees all the points receding.

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It doesn't matter where you are,

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every point is the center of the expansion as it were

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and the galaxies are just being carried along in the flow

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of the expansion of space.

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(tense music)

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Now that most of the world's cosmologist believed

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that the universe had a definite beginning,

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they could start to figure out how it might have worked.

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Scientists began to develop ideas

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about what should happen in these very hot conditions

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in the early universe.

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I think the biggest advance

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was by a fellow named George Gamow.

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He and his collaborators looked at the possibility

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that elements were cooked up in the early universe.

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And this is what's called primordial nucleosynthesis.

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Gamow there that at the very beginning,

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there was only intense heat and energy.

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Over the next few seconds and minutes,

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the energy condensed into the first atoms.

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But they were incomplete atoms.

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The baby universe was too hot for electrons

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to become attracted to the atomic cores.

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(tense music)

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And so you have this very short window

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in which you can create cores of atoms.

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And you just have a long enough to do that

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before the universe then cools down enough

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that you can't do it.

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A bit like turning your oven off.

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You would only be able to develop very light elements,

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like hydrogen and helium, a little bit of lithium.

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And this mixture of elements was

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then remarkably consistent with what astronomers can

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actually see now out in the skies around us.

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But Gamow and his colleagues

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also made a prediction of immense importance.

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He also found that as the universe expands,

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it should leave a remnant radiation background.

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370,000 years after the beginning,

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the expanding universe would've cooled down enough

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for the electrons to become attracted

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to the incomplete atomic cores.

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So the significance of this moment when the electrons

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and protons come together, which we call recombination,

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is that not only is the full hydrogen atom formed

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for the first time,

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but light rays now travel freely through space,

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eventually towards us.

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(gentle music)

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And so the prediction was that we should be bathed

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in this primordial radiation of light rays

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that have indeed been traveling for billions of years,

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since that beginning of the universe time.

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Gamow and his collaborators called

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this first visible remit of creation

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the cosmic microwave background.

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This entire process of the universe expanding

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from an ultra-dense ultra-hot state

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and forging matter from energy was given its famous

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and misleading name by a skeptical British cosmologist

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called Fred Hoyle on a BBC radio program.

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(gentle music)

273
00:12:33,350 --> 00:12:34,750
In a rather derogatory way,

274
00:12:34,750 --> 00:12:37,773
he just described it as a big bang.

275
00:12:37,773 --> 00:12:39,470
(gentle music)

276
00:12:39,470 --> 00:12:41,483
Well, it caught on like these things do.

277
00:12:42,545 --> 00:12:45,890
(dramatic music)

278
00:12:45,890 --> 00:12:47,240
When people call it the big bang,

279
00:12:47,240 --> 00:12:49,490
they almost always picture the wrong thing.

280
00:12:49,490 --> 00:12:52,313
They picture a firecracker at a place and a time,

281
00:12:52,313 --> 00:12:55,350
what we actually observe is the infinite universe expanding

282
00:12:55,350 --> 00:12:58,090
into itself with no actual first moment.

283
00:12:58,090 --> 00:12:59,970
People are shocked when I tell them this.

284
00:12:59,970 --> 00:13:03,280
We've been told the wrong thing by astronomers

285
00:13:03,280 --> 00:13:05,390
and science writers for generations.

286
00:13:05,390 --> 00:13:06,500
And it's hard to take the meaning

287
00:13:06,500 --> 00:13:08,350
of the words that Fred Hoyle gave us.

288
00:13:09,747 --> 00:13:12,300
(dramatic music)

289
00:13:12,300 --> 00:13:14,610
If the big bang really did happen

290
00:13:14,610 --> 00:13:17,160
then finding the cosmic microwave background

291
00:13:17,160 --> 00:13:19,710
that Gamow and his colleagues had predicted

292
00:13:19,710 --> 00:13:21,823
became a vital importance.

293
00:13:23,200 --> 00:13:26,200
The challenging thing is that it would be very difficult

294
00:13:26,200 --> 00:13:31,200
to find because as the universe has grown and cooled down,

295
00:13:33,010 --> 00:13:35,040
this light from the early universe has stretched

296
00:13:35,040 --> 00:13:38,770
its wavelength well beyond the waves that our eyes can see

297
00:13:38,770 --> 00:13:41,280
into microwave wavelength.

298
00:13:41,280 --> 00:13:45,403
And they should now be extremely cold, almost absolute zero.

299
00:13:46,477 --> 00:13:48,830
(gentle music)

300
00:13:48,830 --> 00:13:49,663
The temperature

301
00:13:49,663 --> 00:13:53,830
of this cosmic microwave background, or CMB,

302
00:13:53,830 --> 00:13:55,080
was carefully predicted

303
00:13:55,080 --> 00:13:58,293
by a Princeton scientist called Jim Peebles.

304
00:13:59,200 --> 00:14:02,263
Some of his colleagues then set about trying to find it.

305
00:14:03,160 --> 00:14:05,490
And then completely serendipitously

306
00:14:05,490 --> 00:14:07,043
this wonderful thing happened.

307
00:14:07,948 --> 00:14:09,270
(upbeat music)

308
00:14:09,270 --> 00:14:12,000
When I took a job at Bell Labs,

309
00:14:12,000 --> 00:14:14,400
they had a unique radio antenna,

310
00:14:14,400 --> 00:14:17,238
which we planned to look at some special things

311
00:14:17,238 --> 00:14:19,293
in radio astronomy with.

312
00:14:20,230 --> 00:14:23,890
And what we found was something we weren't looking for.

313
00:14:23,890 --> 00:14:25,360
Rather than collecting light,

314
00:14:25,360 --> 00:14:29,310
that our eyes can see radio astronomy uses antennas

315
00:14:29,310 --> 00:14:32,080
that capture light of much longer wavelengths,

316
00:14:32,080 --> 00:14:34,698
like microwaves and radio waves.

317
00:14:34,698 --> 00:14:37,320
(upbeat music)

318
00:14:37,320 --> 00:14:40,200
Only 26 miles from Princeton University,

319
00:14:40,200 --> 00:14:43,000
Robert Wilson and his colleague Arno Penzias,

320
00:14:43,000 --> 00:14:45,090
wanted to use their radio antenna

321
00:14:45,090 --> 00:14:47,730
to measure the emissions coming from the halo of gas

322
00:14:47,730 --> 00:14:49,343
around our own galaxy.

323
00:14:50,540 --> 00:14:52,130
But in order to do so,

324
00:14:52,130 --> 00:14:54,030
they would first need to calibrate it.

325
00:14:55,090 --> 00:14:56,330
(upbeat music)

326
00:14:56,330 --> 00:14:59,801
Radio astronomers aim their big antennas

327
00:14:59,801 --> 00:15:03,160
at a source they're interested in and get a signal.

328
00:15:03,160 --> 00:15:05,680
But then they turn them off to the side a little bit,

329
00:15:05,680 --> 00:15:08,250
and so they measure the difference between near the source

330
00:15:08,250 --> 00:15:09,747
and on the source.

331
00:15:09,747 --> 00:15:10,580
(upbeat music)

332
00:15:10,580 --> 00:15:12,470
Wherever they pointed their telescope,

333
00:15:12,470 --> 00:15:15,400
they always found background radio emission,

334
00:15:15,400 --> 00:15:19,340
a kind of noisy hiss at a certain frequency.

335
00:15:19,340 --> 00:15:21,723
The background should have been quite small.

336
00:15:22,570 --> 00:15:25,270
And so we had a real conundrum

337
00:15:25,270 --> 00:15:27,470
that the antenna was producing more noise

338
00:15:27,470 --> 00:15:29,329
than we could understand.

339
00:15:29,329 --> 00:15:32,290
(upbeat music)

340
00:15:32,290 --> 00:15:34,010
Arno and Bob set about trying

341
00:15:34,010 --> 00:15:35,850
to locate the source of the noise

342
00:15:35,850 --> 00:15:38,480
that was ruining their experiment.

343
00:15:38,480 --> 00:15:39,720
Yeah, we had a checklist

344
00:15:39,720 --> 00:15:42,300
of something like nine different things.

345
00:15:42,300 --> 00:15:46,200
But things like we had a perfect view of New York City,

346
00:15:46,200 --> 00:15:48,530
could it be that the city is noisy

347
00:15:48,530 --> 00:15:52,830
and that the side lobes of our antenna were picking that up?

348
00:15:52,830 --> 00:15:54,620
Well, we had the perfect instrument.

349
00:15:54,620 --> 00:15:57,913
We turn it around and we look at New York City, nada.

350
00:15:59,570 --> 00:16:02,040
They wondered if the troublesome signals

351
00:16:02,040 --> 00:16:03,720
were coming from the ground.

352
00:16:03,720 --> 00:16:06,260
And so they wheeled a cart around the antenna

353
00:16:06,260 --> 00:16:07,810
with the radio source in it.

354
00:16:07,810 --> 00:16:09,313
But again, nothing.

355
00:16:10,790 --> 00:16:13,970
Bob and Arno were narrowing down their list.

356
00:16:13,970 --> 00:16:16,550
But what if it was something inside the antenna

357
00:16:16,550 --> 00:16:18,123
that was causing the problems?

358
00:16:19,370 --> 00:16:20,610
There was a pair of pigeons

359
00:16:20,610 --> 00:16:23,743
who had taken up roost in the antenna.

360
00:16:25,060 --> 00:16:28,600
They would fly up just about into the cabin of the antenna

361
00:16:28,600 --> 00:16:31,123
and it must have been a nice toasty place to be.

362
00:16:32,440 --> 00:16:34,280
It wasn't necessarily the pigeons

363
00:16:34,280 --> 00:16:36,740
that were suspected of causing the interference,

364
00:16:36,740 --> 00:16:38,703
but something they were leaving behind.

365
00:16:40,350 --> 00:16:43,070
There was this white dielectric material

366
00:16:43,070 --> 00:16:45,970
all over the inside of the horn reflector.

367
00:16:45,970 --> 00:16:49,210
And so we thought it could be radiating.

368
00:16:49,210 --> 00:16:51,690
We first got a trap and put it

369
00:16:51,690 --> 00:16:53,740
where the receiver normally would be

370
00:16:53,740 --> 00:16:55,710
and caught the pigeons.

371
00:16:55,710 --> 00:16:58,910
We put them in a cardboard box and mailed them as far away

372
00:16:58,910 --> 00:17:01,800
as we could in the company mail to a pigeon fan,

373
00:17:01,800 --> 00:17:03,640
here in Whippany, New Jersey.

374
00:17:03,640 --> 00:17:05,460
Well, he took a look at these pigeons,

375
00:17:05,460 --> 00:17:08,860
said, "these are junk pigeons," and let them go.

376
00:17:08,860 --> 00:17:12,671
Well a day or so later here are the pigeons back.

377
00:17:12,671 --> 00:17:15,880
(chuckles) So that didn't work.

378
00:17:15,880 --> 00:17:18,580
Our technician brought in a shotgun

379
00:17:18,580 --> 00:17:21,763
and in the name of science dispensed with the pigeons.

380
00:17:23,275 --> 00:17:24,476
(upbeat music)

381
00:17:24,476 --> 00:17:25,860
(gunshot blasting)

382
00:17:25,860 --> 00:17:28,700
In short, none of the things we could think of

383
00:17:28,700 --> 00:17:31,563
and do anything about actually made any difference.

384
00:17:33,116 --> 00:17:33,949
(upbeat music)

385
00:17:33,949 --> 00:17:36,220
A hint at where their problems might lie,

386
00:17:36,220 --> 00:17:38,610
came when Arno had a chance conversation

387
00:17:38,610 --> 00:17:40,670
with the fellow astronomer.

388
00:17:40,670 --> 00:17:41,777
He said to Arno,

389
00:17:41,777 --> 00:17:44,120
"what's happening with your crazy experiment?"

390
00:17:44,120 --> 00:17:45,357
And Arno laid it on him,

391
00:17:45,357 --> 00:17:48,190
"We've got this excess noise in our antenna.

392
00:17:48,190 --> 00:17:49,460
We can't find it."

393
00:17:49,460 --> 00:17:52,110
He said, "You oughta talk to Bob Dicke at Princeton."

394
00:17:53,470 --> 00:17:55,050
Bob Dicke was the colleague

395
00:17:55,050 --> 00:17:57,520
of Jim Peebles at Princeton University,

396
00:17:57,520 --> 00:18:00,540
whose team were already actively looking for evidence

397
00:18:00,540 --> 00:18:03,143
of the radiation predicted by the big bang theory.

398
00:18:04,600 --> 00:18:06,800
Although Peebles had calculated what kind

399
00:18:06,800 --> 00:18:08,750
of radiation they were looking for,

400
00:18:08,750 --> 00:18:11,530
their experiments were only being calibrated

401
00:18:11,530 --> 00:18:12,933
and had yet to begin.

402
00:18:14,280 --> 00:18:17,080
The team were eating lunch together when the phone rang.

403
00:18:18,416 --> 00:18:19,610
Dicke picked up the phone

404
00:18:19,610 --> 00:18:22,850
and they heard atmospheric radiation,

405
00:18:22,850 --> 00:18:26,240
sky temperature, antennalized,

406
00:18:26,240 --> 00:18:28,223
all the things they were interested in.

407
00:18:29,126 --> 00:18:30,577
Dicke put down the phone and said,

408
00:18:30,577 --> 00:18:32,647
"Boys, we've been scooped."

409
00:18:36,060 --> 00:18:38,320
Robert Wilson and Arno Penzias

410
00:18:38,320 --> 00:18:39,520
had accidentally found

411
00:18:39,520 --> 00:18:42,870
what Jim Peebles and George Gamow had predicted.

412
00:18:42,870 --> 00:18:44,570
We invited them over.

413
00:18:44,570 --> 00:18:48,060
They looked at our antenna and all the measuring system,

414
00:18:48,060 --> 00:18:50,510
and agreed that we'd done the right thing.

415
00:18:50,510 --> 00:18:52,050
We went down to the conference room

416
00:18:52,050 --> 00:18:55,700
and they told us about how a big bang might produce

417
00:18:55,700 --> 00:18:58,460
a universe full of radiation.

418
00:18:58,460 --> 00:19:00,550
Wilson, Penzias, and Peebles

419
00:19:00,550 --> 00:19:02,530
were all awarded Nobel Prizes

420
00:19:02,530 --> 00:19:05,090
for their parts in this momentous discovery.

421
00:19:05,090 --> 00:19:07,130
And suddenly it changed everything.

422
00:19:07,130 --> 00:19:10,510
The fact that we see the galaxies expanding around us.

423
00:19:10,510 --> 00:19:13,410
We see the elements in the right abundances

424
00:19:13,410 --> 00:19:15,080
that you'd expect from a hot big bang.

425
00:19:15,080 --> 00:19:17,660
And then we see this radiation coming

426
00:19:17,660 --> 00:19:19,560
from all directions in the sky.

427
00:19:19,560 --> 00:19:21,990
Those three things became the pillars

428
00:19:21,990 --> 00:19:24,400
of the big bang theory.

429
00:19:24,400 --> 00:19:26,230
So now scientists had a picture

430
00:19:26,230 --> 00:19:29,120
of a universe that expands from a big bang,

431
00:19:29,120 --> 00:19:31,600
cooks up basic elements in the inferno,

432
00:19:31,600 --> 00:19:33,823
and leaves behind a detectable background.

433
00:19:35,630 --> 00:19:38,410
But that couldn't be the whole picture.

434
00:19:38,410 --> 00:19:41,750
The hot big bang model was on pretty firm footing,

435
00:19:41,750 --> 00:19:43,723
{\an8}but there were definitely some puzzles.

436
00:19:44,804 --> 00:19:46,100
{\an8}(upbeat music)

437
00:19:46,100 --> 00:19:49,150
{\an8}This CMB radiation did appear indeed

438
00:19:49,150 --> 00:19:51,350
to be the same temperature everywhere.

439
00:19:51,350 --> 00:19:52,700
And the that's really weird

440
00:19:52,700 --> 00:19:55,070
because you're receiving a ray of light

441
00:19:55,070 --> 00:19:56,590
from all different directions.

442
00:19:56,590 --> 00:19:58,110
And those rays of light have traveled

443
00:19:58,110 --> 00:20:00,260
for 14 billion years to reach you.

444
00:20:00,260 --> 00:20:02,920
And they could only have achieved the same temperature

445
00:20:02,920 --> 00:20:05,028
if they were once in contact.

446
00:20:05,028 --> 00:20:07,090
(upbeat music)

447
00:20:07,090 --> 00:20:08,260
There was a second problem,

448
00:20:08,260 --> 00:20:10,650
which is that the universe seemed

449
00:20:10,650 --> 00:20:13,344
to be something known as flat.

450
00:20:13,344 --> 00:20:15,940
(upbeat music)

451
00:20:15,940 --> 00:20:18,530
The universe is observed to have very close

452
00:20:18,530 --> 00:20:20,700
to what's known as spatial flatness.

453
00:20:20,700 --> 00:20:21,840
What is spatial flatness?

454
00:20:21,840 --> 00:20:25,480
So if you imagine yourself on the surface of the Earth,

455
00:20:25,480 --> 00:20:27,610
the Earth, locally, looks very flat,

456
00:20:27,610 --> 00:20:29,672
meaning that if you go to a sidewalk

457
00:20:29,672 --> 00:20:33,100
and you draw a triangle with three straight lines to it,

458
00:20:33,100 --> 00:20:33,933
you will get,

459
00:20:33,933 --> 00:20:36,720
when you sum up those three angles, 180 degrees.

460
00:20:36,720 --> 00:20:38,870
However, if you make that triangle bigger

461
00:20:38,870 --> 00:20:42,580
and you put one vertex of the triangle in Bangkok,

462
00:20:42,580 --> 00:20:44,472
one in Mexico city, and one at the South Pole,

463
00:20:44,472 --> 00:20:49,060
that triangle has about 270 degrees

464
00:20:49,060 --> 00:20:51,360
between its three angles when summed together.

465
00:20:52,340 --> 00:20:54,860
Now imagine going off the surface of the Earth.

466
00:20:54,860 --> 00:20:58,180
Pick three stars, measure the angle that they sub 10,

467
00:20:58,180 --> 00:20:59,050
and make the triangle,

468
00:20:59,050 --> 00:21:02,700
and observe their three interior angles and add those up.

469
00:21:02,700 --> 00:21:05,260
It turns out no matter how big a triangle you make

470
00:21:05,260 --> 00:21:10,150
in the universe those angles always add up to 180 degrees.

471
00:21:10,150 --> 00:21:12,650
So it's very, very striking that the universe

472
00:21:12,650 --> 00:21:15,650
was fine tuned to parts in a billion or a trillion

473
00:21:15,650 --> 00:21:17,860
in its curvature, right after the big bang.

474
00:21:17,860 --> 00:21:19,410
How could that possibly happen?

475
00:21:20,582 --> 00:21:22,950
(upbeat music)

476
00:21:22,950 --> 00:21:25,640
Physicists were pretty confident about their model

477
00:21:25,640 --> 00:21:28,210
of how the universe worked down to a time

478
00:21:28,210 --> 00:21:30,230
of about one second,

479
00:21:30,230 --> 00:21:31,954
where the conditions had to be right

480
00:21:31,954 --> 00:21:34,070
to start to form these light elements.

481
00:21:34,070 --> 00:21:37,320
So how flat would the universe have to have been then

482
00:21:37,320 --> 00:21:39,300
to explain how flat it is now?

483
00:21:39,300 --> 00:21:43,490
And it has to be extremely flat to parts

484
00:21:43,490 --> 00:21:45,020
in 10 to a large number.

485
00:21:45,020 --> 00:21:49,510
And that seemed just very odd that that would be the case.

486
00:21:49,510 --> 00:21:51,960
So the solution to both of these problems

487
00:21:53,490 --> 00:21:55,293
is something called inflation.

488
00:21:56,800 --> 00:21:59,880
I didn't expect that I'm going to be a cosmologist.

489
00:21:59,880 --> 00:22:03,650
I thought that I'm going to work on particle physics,

490
00:22:03,650 --> 00:22:06,435
but then unexpected things happen.

491
00:22:06,435 --> 00:22:07,680
(upbeat music)

492
00:22:07,680 --> 00:22:10,100
The original of cosmic inflation

493
00:22:10,100 --> 00:22:13,800
was built independently by Alan Guth in the US

494
00:22:13,800 --> 00:22:17,310
and Alexei Starobinsky in the Soviet union.

495
00:22:17,310 --> 00:22:21,810
Inflation introduced a new phase at the very beginning

496
00:22:21,810 --> 00:22:25,530
of the universe, before the formation of atoms

497
00:22:25,530 --> 00:22:29,730
in which there was a sudden accelerated expansion

498
00:22:29,730 --> 00:22:30,923
of the universe.

499
00:22:32,510 --> 00:22:35,990
Inflation would've been staggeringly brief

500
00:22:35,990 --> 00:22:38,660
and increased the size of the universe by a scale

501
00:22:38,660 --> 00:22:41,313
that is hard to comprehend and even to say.

502
00:22:42,500 --> 00:22:45,230
In much less than a trillionth of a second,

503
00:22:45,230 --> 00:22:46,990
the universe would've expanded

504
00:22:46,990 --> 00:22:51,250
by 100 trillion-trillion times.

505
00:22:51,250 --> 00:22:55,210
And you would very rapidly blow up a space smaller

506
00:22:55,210 --> 00:22:59,950
than an atom to larger than a galaxy very, very, very fast.

507
00:22:59,950 --> 00:23:03,360
This means the overall universe is much bigger

508
00:23:03,360 --> 00:23:07,040
than we can ever observe from our own bubble within it.

509
00:23:07,040 --> 00:23:09,610
So it's a very fundamental rule in physics

510
00:23:09,610 --> 00:23:11,230
that nothing can move through

511
00:23:11,230 --> 00:23:13,640
the fabric of space faster than light.

512
00:23:13,640 --> 00:23:14,830
But that actually says nothing

513
00:23:14,830 --> 00:23:16,850
about the fabric of space itself.

514
00:23:16,850 --> 00:23:19,630
The fabric of space itself can expand faster than

515
00:23:19,630 --> 00:23:21,140
the speed of light in these theories.

516
00:23:21,140 --> 00:23:22,710
There's nothing to prevent that.

517
00:23:22,710 --> 00:23:26,150
And that's what happens during the inflationary phase.

518
00:23:26,150 --> 00:23:28,920
The distance between points is growing faster

519
00:23:28,920 --> 00:23:31,780
than the speed at light can close the gap

520
00:23:31,780 --> 00:23:34,230
between those two points so to speak.

521
00:23:34,230 --> 00:23:35,550
But there was a brief moment

522
00:23:35,550 --> 00:23:37,610
before inflation began

523
00:23:37,610 --> 00:23:41,190
in which the universe expanded much more slowly.

524
00:23:41,190 --> 00:23:42,900
Those regions that we observe in the sky,

525
00:23:42,900 --> 00:23:43,770
being the same temperature,

526
00:23:43,770 --> 00:23:46,500
they were all connected at this earlier time

527
00:23:46,500 --> 00:23:49,633
before the universe got ripped apart by inflation.

528
00:23:51,010 --> 00:23:53,830
Inflation also explains why the universe is so flat

529
00:23:53,830 --> 00:23:57,820
because that expansion takes whatever geometry universe

530
00:23:57,820 --> 00:24:00,870
had prior to inflation and stretches it out tremendously.

531
00:24:00,870 --> 00:24:02,530
So that local region

532
00:24:02,530 --> 00:24:04,803
that we can see today looks very, very flat.

533
00:24:08,170 --> 00:24:11,070
It's like, if we're on the surface of the Earth now,

534
00:24:11,070 --> 00:24:12,770
we know the surface of the Earth is curved.

535
00:24:12,770 --> 00:24:14,570
It has continents and oceans

536
00:24:14,570 --> 00:24:15,960
and suddenly through stretching,

537
00:24:15,960 --> 00:24:19,140
all we can have access to is our backyards.

538
00:24:19,140 --> 00:24:22,633
Well now our backyard is going to look rather locally flat.

539
00:24:27,170 --> 00:24:29,460
The original theory of cosmic inflation

540
00:24:29,460 --> 00:24:32,670
utilized a core concept taken from quantum theory

541
00:24:32,670 --> 00:24:35,710
that suggests that there can never be such a thing

542
00:24:35,710 --> 00:24:36,803
as zero energy.

543
00:24:37,760 --> 00:24:40,190
Even a random spot in the vacuum of space

544
00:24:40,190 --> 00:24:43,603
has quantum particles fizzing in and out of existence.

545
00:24:44,880 --> 00:24:46,910
In this picture of the big bang,

546
00:24:46,910 --> 00:24:49,140
the tiny and seemingly empty spec

547
00:24:49,140 --> 00:24:51,000
from which the universe would grow

548
00:24:51,000 --> 00:24:53,093
was bursting with potential energy.

549
00:24:55,845 --> 00:24:59,590
So this is a strange way of producing lots of particles,

550
00:24:59,590 --> 00:25:01,640
lots of energy, practically from nothing.

551
00:25:02,850 --> 00:25:04,740
In models for inflation,

552
00:25:04,740 --> 00:25:08,400
the universe that would've been extremely compressed

553
00:25:08,400 --> 00:25:10,800
was composed of like an energy field.

554
00:25:10,800 --> 00:25:15,390
And it would be the stored up energy in that field

555
00:25:15,390 --> 00:25:18,490
that would be released a little bit like releasing a spring.

556
00:25:18,490 --> 00:25:20,500
They would have this sort of potential energy,

557
00:25:20,500 --> 00:25:22,663
this energy that's raring to go.

558
00:25:23,740 --> 00:25:25,550
This newly unleashed energy

559
00:25:25,550 --> 00:25:27,580
and the rapid creation of space

560
00:25:27,580 --> 00:25:29,160
would propel a chain reaction

561
00:25:29,160 --> 00:25:32,163
of bubbles of potential energy exploding.

562
00:25:33,890 --> 00:25:35,930
And as a result of it,

563
00:25:35,930 --> 00:25:39,033
the universe does not look like one bubble,

564
00:25:40,060 --> 00:25:42,740
but instead it looks bubbles producing bubbles,

565
00:25:42,740 --> 00:25:45,340
producing bubbles, producing bubbles, forever.

566
00:25:45,340 --> 00:25:47,190
It becomes a fractal.

567
00:25:47,190 --> 00:25:49,840
So the classical picture of the universe,

568
00:25:49,840 --> 00:25:51,780
which is hung big and round,

569
00:25:51,780 --> 00:25:53,460
no, it's not a big and round.

570
00:25:53,460 --> 00:25:55,920
It's something well like three

571
00:25:55,920 --> 00:25:58,650
of universes growing like that.

572
00:25:58,650 --> 00:25:59,980
And this mechanism,

573
00:25:59,980 --> 00:26:02,150
with its random fluctuations,

574
00:26:02,150 --> 00:26:05,353
is ultimately responsible for us being here at all.

575
00:26:07,280 --> 00:26:10,220
So the idea of inflation is that all structure

576
00:26:10,220 --> 00:26:13,930
in the universe originated from quantum fluctuations during

577
00:26:13,930 --> 00:26:17,053
this hyper expansion phase at a very early time.

578
00:26:18,560 --> 00:26:20,500
If the quantum fluctuation's in the big bang

579
00:26:20,500 --> 00:26:23,140
were the correct description plus inflation,

580
00:26:23,140 --> 00:26:24,750
then we should have roughly the pattern

581
00:26:24,750 --> 00:26:27,450
{\an8}of hot and cold spots that we see in a sky.

582
00:26:27,450 --> 00:26:30,780
{\an8}And that match with where the galaxies are today.

583
00:26:30,780 --> 00:26:31,920
Sure enough, they do.

584
00:26:31,920 --> 00:26:35,840
The current idea is gravity acts on the denser regions

585
00:26:35,840 --> 00:26:37,610
and stops them from expanding,

586
00:26:37,610 --> 00:26:40,110
pulls the material back together again to make a galaxy,

587
00:26:40,110 --> 00:26:41,430
and then planets and stars.

588
00:26:41,430 --> 00:26:43,990
So we're here because of those spots

589
00:26:43,990 --> 00:26:45,640
in the big bang radiation,

590
00:26:45,640 --> 00:26:48,483
plus gravity, which is a pretty amazing result.

591
00:26:49,415 --> 00:26:51,690
(tense music)

592
00:26:51,690 --> 00:26:53,190
But inflationary theory

593
00:26:53,190 --> 00:26:56,403
in its original form had a fundamental problem.

594
00:26:58,300 --> 00:27:00,630
This energy would sort of permeate space

595
00:27:00,630 --> 00:27:03,070
and would be expanding incredibly fast.

596
00:27:03,070 --> 00:27:05,800
And somehow you have to stop that from happening

597
00:27:05,800 --> 00:27:09,273
in a gradual and smoothly controlled way.

598
00:27:10,840 --> 00:27:12,940
For about a year or more,

599
00:27:12,940 --> 00:27:15,430
many different people worked on it.

600
00:27:15,430 --> 00:27:18,920
Steven Hawking and his collaborators wrote a paper saying

601
00:27:18,920 --> 00:27:22,403
that it's impossible to solve this particular problem.

602
00:27:23,370 --> 00:27:26,493
But late one night, Andrei had a brain wave.

603
00:27:27,330 --> 00:27:30,097
I wake up my wife and I said,

604
00:27:30,097 --> 00:27:32,827
"I think that I know how the universe was born."

605
00:27:34,440 --> 00:27:36,800
During the summer of 1981,

606
00:27:36,800 --> 00:27:39,030
Andrei wrote a paper on the modified theory,

607
00:27:39,030 --> 00:27:41,796
which he called new inflation.

608
00:27:41,796 --> 00:27:44,240
(gentle music)

609
00:27:44,240 --> 00:27:46,120
And so what Andrei Linde came up with

610
00:27:46,120 --> 00:27:50,060
was a different mechanism for gently sort of rolling

611
00:27:50,060 --> 00:27:52,520
into a smoother expansion

612
00:27:52,520 --> 00:27:54,570
than had been come up with to begin with.

613
00:27:55,670 --> 00:27:59,020
And in October, there was a conference in Moscow,

614
00:27:59,020 --> 00:28:01,097
lots of brilliant people came,

615
00:28:01,097 --> 00:28:02,910
and one of them was Steven Hawking.

616
00:28:02,910 --> 00:28:04,830
And they gave a talk at this conference

617
00:28:04,830 --> 00:28:06,660
and everybody got very excited.

618
00:28:06,660 --> 00:28:10,370
But next day, I came to the talk by Steven Hawking.

619
00:28:10,370 --> 00:28:13,670
Unexpectedly, they suggested me to translate.

620
00:28:13,670 --> 00:28:17,630
Steve would say one word, his student say one word,

621
00:28:17,630 --> 00:28:18,940
I translated this word.

622
00:28:18,940 --> 00:28:22,207
It was about old inflation of the theory.

623
00:28:22,207 --> 00:28:23,320
And then Steven said,

624
00:28:23,320 --> 00:28:26,090
"and recently was an interesting suggestion

625
00:28:26,090 --> 00:28:29,970
about how to improve it by Andrei Linde."

626
00:28:29,970 --> 00:28:32,010
And I happily translated.

627
00:28:32,010 --> 00:28:34,137
And next second he said,

628
00:28:34,137 --> 00:28:36,717
"but this suggestion is completely wrong."

629
00:28:38,360 --> 00:28:43,360
And for half an hour, I was translating why my own theory,

630
00:28:43,900 --> 00:28:46,810
which I had just reported the day before,

631
00:28:46,810 --> 00:28:49,790
why it does not work, et cetera, et cetera.

632
00:28:49,790 --> 00:28:52,580
After the lecture, Andre asked Steven

633
00:28:52,580 --> 00:28:54,520
if they could talk in more detail.

634
00:28:54,520 --> 00:28:57,780
they retired to a side room where for more than two hours,

635
00:28:57,780 --> 00:29:01,460
they discussed Andrei's modification to inflation.

636
00:29:01,460 --> 00:29:03,867
He said something and his student would say,

637
00:29:03,867 --> 00:29:05,890
"but you didn't say that before."

638
00:29:05,890 --> 00:29:07,830
And this thing continued.

639
00:29:07,830 --> 00:29:09,543
I ended up in his hotel.

640
00:29:10,470 --> 00:29:13,734
He was showing me photographs of his family

641
00:29:13,734 --> 00:29:15,283
and we became friends.

642
00:29:16,420 --> 00:29:18,840
Hawking realized that Linde had solved

643
00:29:18,840 --> 00:29:20,840
the issues that were plaguing inflation.

644
00:29:21,690 --> 00:29:24,540
He had proposed a mechanism by which inflation

645
00:29:24,540 --> 00:29:27,583
could not only start, but gracefully come to an end.

646
00:29:28,490 --> 00:29:30,490
Andrei was invited to come back to Cambridge

647
00:29:30,490 --> 00:29:33,230
and work with Steven where over the next year

648
00:29:33,230 --> 00:29:36,460
they and their fellow cosmologist molded a simpler

649
00:29:36,460 --> 00:29:38,660
and more robust inflationary theory

650
00:29:39,950 --> 00:29:42,863
that became the centerpiece of big bang cosmology.

651
00:29:43,887 --> 00:29:45,810
(tense music)

652
00:29:45,810 --> 00:29:48,670
By the late 1990s cosmologists knew

653
00:29:48,670 --> 00:29:51,230
that there was some evidence for inflation,

654
00:29:51,230 --> 00:29:53,380
but they wanted to find the smoking gun

655
00:29:53,380 --> 00:29:55,923
that would tell them that it must have happened.

656
00:29:56,880 --> 00:29:59,060
And they were sure that it could be found

657
00:29:59,060 --> 00:30:02,223
in patterns within the cosmic microwave background.

658
00:30:03,350 --> 00:30:06,780
If inflation happens a likely thing to come from it

659
00:30:06,780 --> 00:30:09,360
is this really particular signature

660
00:30:09,360 --> 00:30:12,300
that we're all searching for now with our telescopes.

661
00:30:12,300 --> 00:30:17,300
And it's an imprint of ripples in space time

662
00:30:17,527 --> 00:30:22,527
that would've been imprinted during that inflation process.

663
00:30:22,980 --> 00:30:24,530
The patterns they were looking for

664
00:30:24,530 --> 00:30:27,510
are called polarization patterns.

665
00:30:27,510 --> 00:30:29,103
But what is polarization?

666
00:30:29,940 --> 00:30:32,980
Any given ray of light is a fluctuation

667
00:30:32,980 --> 00:30:34,630
in the electric field and a fluctuation

668
00:30:34,630 --> 00:30:37,400
in the magnetic field that are 90 degrees apart.

669
00:30:37,400 --> 00:30:39,670
And then this whole wave train is moving

670
00:30:39,670 --> 00:30:41,170
along the third direction.

671
00:30:41,170 --> 00:30:43,550
As you rotate around the direction of motion,

672
00:30:43,550 --> 00:30:44,980
these are other polarizations.

673
00:30:44,980 --> 00:30:47,560
So you have a continuous range of polarizations

674
00:30:47,560 --> 00:30:49,273
for each individual ray of light.

675
00:30:50,720 --> 00:30:52,110
The polarization properties

676
00:30:52,110 --> 00:30:55,360
of an individual ray of light can tell us a story

677
00:30:55,360 --> 00:30:58,723
about what has happened to the light on its journey to us.

678
00:30:59,680 --> 00:31:01,280
Now most of those fluctuations

679
00:31:01,280 --> 00:31:02,767
we see in the microwave background,

680
00:31:02,767 --> 00:31:04,150
but they're like a sound wave.

681
00:31:04,150 --> 00:31:07,830
It's a compression wave traveling through the universe.

682
00:31:07,830 --> 00:31:10,780
This first common type of fluctuation

683
00:31:10,780 --> 00:31:14,070
creates either a cross like or circular pattern,

684
00:31:14,070 --> 00:31:15,753
which is called an E-mode,

685
00:31:16,710 --> 00:31:19,960
but there is another pattern called a B-mode.

686
00:31:19,960 --> 00:31:22,090
And this is a one that is crucial

687
00:31:22,090 --> 00:31:23,983
to finding evidence for inflation.

688
00:31:24,830 --> 00:31:25,663
In Einsteins theory,

689
00:31:25,663 --> 00:31:28,840
you can also have fluctuations in space time

690
00:31:28,840 --> 00:31:30,970
called gravitational waves.

691
00:31:30,970 --> 00:31:33,590
And they don't act like a density wave

692
00:31:33,590 --> 00:31:36,390
that compresses and rarifies.

693
00:31:36,390 --> 00:31:39,720
Instead they squeeze space in one direction

694
00:31:39,720 --> 00:31:40,970
and stretch it in the other direction

695
00:31:40,970 --> 00:31:43,170
while they're propagating in the third dimension.

696
00:31:43,170 --> 00:31:47,360
Those fluctuations have a very, very specific signature.

697
00:31:47,360 --> 00:31:51,070
They will have imprinted a particular form,

698
00:31:51,070 --> 00:31:53,730
a particular swirliness, actually.

699
00:31:53,730 --> 00:31:56,400
And if we could detect this pattern of swirling,

700
00:31:56,400 --> 00:31:59,100
twisting polarization in the microwave background,

701
00:31:59,100 --> 00:32:01,870
that would be perhaps indirect evidence

702
00:32:01,870 --> 00:32:03,440
that inflation took place.

703
00:32:03,440 --> 00:32:06,450
If it could be observed to be truly cosmological,

704
00:32:06,450 --> 00:32:09,560
not caused by some systematic error in the instrument

705
00:32:09,560 --> 00:32:11,290
or in the galaxy or something else,

706
00:32:11,290 --> 00:32:12,510
that would be as close to

707
00:32:12,510 --> 00:32:14,390
what was called smoking gun evidence

708
00:32:14,390 --> 00:32:15,693
that inflation took place.

709
00:32:16,659 --> 00:32:17,630
(exciting music)

710
00:32:17,630 --> 00:32:21,730
In 1996 the European Space Agency, ESA,

711
00:32:21,730 --> 00:32:24,930
started planning a space mission called Planck

712
00:32:24,930 --> 00:32:27,490
to map the cosmic microwave background

713
00:32:27,490 --> 00:32:28,913
at very high resolution.

714
00:32:29,850 --> 00:32:32,810
In the sky maps you will see the different colors show

715
00:32:32,810 --> 00:32:34,700
the temperature variations.

716
00:32:34,700 --> 00:32:37,610
Blues and yellows are hottest, through to greens,

717
00:32:37,610 --> 00:32:39,673
and then red for the coldest areas.

718
00:32:41,610 --> 00:32:45,690
Initially, we were not planning to measure polarization

719
00:32:45,690 --> 00:32:47,670
when we first started out with the project.

720
00:32:47,670 --> 00:32:50,730
Planck's prime mission was to do the ultimate job,

721
00:32:50,730 --> 00:32:53,170
measuring the temperature variations

722
00:32:53,170 --> 00:32:54,410
in the microwave background.

723
00:32:54,410 --> 00:32:58,230
People had not really realized how important

724
00:32:58,230 --> 00:33:02,350
and how much information polarization signals would carry.

725
00:33:02,350 --> 00:33:04,593
So it was not the primary goal.

726
00:33:05,540 --> 00:33:06,600
A separate project

727
00:33:06,600 --> 00:33:09,720
from around the same time called Boomerang,

728
00:33:09,720 --> 00:33:11,550
didn't go into space,

729
00:33:11,550 --> 00:33:14,850
but used balloons to make high sensitivity observations

730
00:33:14,850 --> 00:33:15,743
of the CMB.

731
00:33:15,743 --> 00:33:18,000
(upbeat music)

732
00:33:18,000 --> 00:33:19,680
My last year as a graduate student,

733
00:33:19,680 --> 00:33:20,760
I worked on developing

734
00:33:20,760 --> 00:33:23,773
new technology detectors for Boomerang.

735
00:33:23,773 --> 00:33:27,450
Now the detectors that were developed on Boomerang turned

736
00:33:27,450 --> 00:33:30,990
into the detectors on the Planck satellite,

737
00:33:30,990 --> 00:33:33,170
and they were developed here at JPL.

738
00:33:33,170 --> 00:33:35,530
In the midst of Planck's development,

739
00:33:35,530 --> 00:33:37,870
the science team got more and more interested

740
00:33:37,870 --> 00:33:40,520
with polarization measurement.

741
00:33:40,520 --> 00:33:42,240
So I was also a postdoc

742
00:33:42,240 --> 00:33:44,270
at the California Institute of Technology.

743
00:33:44,270 --> 00:33:46,500
I was really fascinated by building a telescope

744
00:33:46,500 --> 00:33:48,360
that was only sensitive to the polarization

745
00:33:48,360 --> 00:33:50,600
of the microwave background.

746
00:33:50,600 --> 00:33:53,338
Myself and Brian Keating, we came up with an approach

747
00:33:53,338 --> 00:33:55,670
that would call B-modes or bust.

748
00:33:55,670 --> 00:33:58,510
We proposed to the CalTech president at the time

749
00:33:58,510 --> 00:33:59,773
to get some seed money.

750
00:34:01,420 --> 00:34:02,340
We said, "We're going to look

751
00:34:02,340 --> 00:34:05,120
for this inflationary gravitational wave signal,

752
00:34:05,120 --> 00:34:06,810
to look and see if we can see it.

753
00:34:06,810 --> 00:34:09,090
And build an experiment that's just tailor made

754
00:34:09,090 --> 00:34:11,800
to do that one thing and do it really well."

755
00:34:11,800 --> 00:34:13,890
We would've loved to take it into space,

756
00:34:13,890 --> 00:34:16,980
but space born experiments will cost you anywhere

757
00:34:16,980 --> 00:34:19,350
from a hundred to a thousand times more than

758
00:34:19,350 --> 00:34:20,890
their ground based equivalent.

759
00:34:20,890 --> 00:34:22,650
And we believed we could do it from the ground

760
00:34:22,650 --> 00:34:26,453
if we went to an exquisite site like the South Pole.

761
00:34:27,830 --> 00:34:29,960
Brian, Jamie, and their colleagues,

762
00:34:29,960 --> 00:34:33,010
established BICEP, Background Imaging

763
00:34:33,010 --> 00:34:35,823
of Cosmic Extra-Galactic Polarization.

764
00:34:35,823 --> 00:34:36,890
(upbeat music)

765
00:34:36,890 --> 00:34:40,737
I started working on it full-time 2007, 2008.

766
00:34:40,737 --> 00:34:42,130
(upbeat music)

767
00:34:42,130 --> 00:34:44,050
The stage was set for a battle

768
00:34:44,050 --> 00:34:46,450
between two very different missions,

769
00:34:46,450 --> 00:34:48,723
both sharing closely related technology,

770
00:34:50,316 --> 00:34:52,140
(tense music)

771
00:34:52,140 --> 00:34:55,210
But for the Planck team, they still did not really believe

772
00:34:55,210 --> 00:34:57,063
that BICEP was a competitor.

773
00:34:58,040 --> 00:34:59,570
Within the Planck community,

774
00:34:59,570 --> 00:35:02,030
we were not really all that concerned.

775
00:35:02,030 --> 00:35:04,270
What BICEP was trying to achieve was quite

776
00:35:04,270 --> 00:35:07,393
a different thing, using quite a different approach.

777
00:35:08,320 --> 00:35:12,550
The really novel thing about BICEP is the telescope.

778
00:35:12,550 --> 00:35:15,020
So we're looking for swirly patterns in the polarization

779
00:35:15,020 --> 00:35:18,890
on scales several times bigger than the full moon.

780
00:35:18,890 --> 00:35:21,540
Now you don't need a very big telescope to do that.

781
00:35:21,540 --> 00:35:25,530
Telescope of 25 centimeters or so would be just fine.

782
00:35:25,530 --> 00:35:28,060
And actually that brings a huge number of advantages

783
00:35:28,060 --> 00:35:29,830
because I can take that small telescope

784
00:35:29,830 --> 00:35:32,890
and I can spin it around to take out any polarization

785
00:35:32,890 --> 00:35:33,930
that's in the instrument.

786
00:35:33,930 --> 00:35:37,290
It's really hard to do that with a large telescope.

787
00:35:37,290 --> 00:35:39,900
The small size of the BICEP telescope

788
00:35:39,900 --> 00:35:42,330
also makes it easier to cool.

789
00:35:42,330 --> 00:35:45,380
The ancient light of the cosmic microwave background

790
00:35:45,380 --> 00:35:47,550
is now extremely cold.

791
00:35:47,550 --> 00:35:49,030
So in order to see it,

792
00:35:49,030 --> 00:35:52,360
the telescope itself must be kept very cold.

793
00:35:52,360 --> 00:35:54,430
I can cool that whole telescope down

794
00:35:54,430 --> 00:35:56,540
to four degrees above absolute zero.

795
00:35:56,540 --> 00:35:59,160
And that's very hard to do with a large telescope.

796
00:35:59,160 --> 00:36:02,730
The first generation of BICEP used these kinds of detectors

797
00:36:02,730 --> 00:36:04,977
we developed for Planck called a balometer.

798
00:36:04,977 --> 00:36:07,786
And the basic idea is you take something that absorbs,

799
00:36:07,786 --> 00:36:10,180
in this case, millimeter wave radiation,

800
00:36:10,180 --> 00:36:13,410
and you stick a sensitive thermometer to that absorber.

801
00:36:13,410 --> 00:36:15,650
And if any radiation hits the absorber

802
00:36:15,650 --> 00:36:17,437
you measure the increase in temperature

803
00:36:17,437 --> 00:36:19,253
using the thermometer.

804
00:36:19,253 --> 00:36:21,380
(tense music)

805
00:36:21,380 --> 00:36:23,310
The BICEP experiment is located

806
00:36:23,310 --> 00:36:26,803
at the Amundsen-Scott South Pole Station in Antarctica.

807
00:36:28,370 --> 00:36:31,240
The South Pole is flat, it's featureless, it's cold,

808
00:36:31,240 --> 00:36:33,120
it's barren, it's dark.

809
00:36:33,120 --> 00:36:34,410
Literally six months of the year

810
00:36:34,410 --> 00:36:37,150
the sun is below the horizon and we pay one person

811
00:36:37,150 --> 00:36:40,320
to sit there for the next nine months of his or her life.

812
00:36:40,320 --> 00:36:42,073
But we call that person a winter-over

813
00:36:42,073 --> 00:36:45,350
and we always joke, "We're gonna pay you $75,000

814
00:36:45,350 --> 00:36:47,780
and all you have to do is work for one night,"

815
00:36:47,780 --> 00:36:49,793
because that's all they'll be there for.

816
00:36:51,000 --> 00:36:52,430
(tense music)

817
00:36:52,430 --> 00:36:54,370
So it would sit there at the South Pole

818
00:36:54,370 --> 00:36:57,470
and it would scan back and forth for years on end,

819
00:36:57,470 --> 00:36:59,630
accumulating data, storing the data.

820
00:36:59,630 --> 00:37:01,330
We're testing it, we're analyzing it,

821
00:37:01,330 --> 00:37:02,823
we're looking for artifacts.

822
00:37:03,830 --> 00:37:08,120
BICEP1 was created in 2001 and we deployed it in 2005.

823
00:37:08,120 --> 00:37:11,440
It took data from 2006 till 2009.

824
00:37:11,440 --> 00:37:13,560
We then decommissioned it to make way for a bigger,

825
00:37:13,560 --> 00:37:16,160
better instrument called BICEP2.

826
00:37:16,160 --> 00:37:18,150
Those first three years really showed

827
00:37:18,150 --> 00:37:20,830
that the method worked really, really well.

828
00:37:20,830 --> 00:37:23,040
Meanwhile, much of the field is struggling

829
00:37:23,040 --> 00:37:25,863
with larger telescopes to do these kinds of measurements.

830
00:37:27,851 --> 00:37:29,659
(tense music)

831
00:37:29,659 --> 00:37:31,710
(speaking foreign language)

832
00:37:31,710 --> 00:37:34,410
After 13 years of careful development,

833
00:37:34,410 --> 00:37:36,550
the European Space Agency was ready

834
00:37:36,550 --> 00:37:40,197
to launch the Planck spacecraft in May 2009.

835
00:37:40,197 --> 00:37:42,428
(rocket engine rumbling)
(tense music)

836
00:37:42,428 --> 00:37:45,690
I was very happy to be part of the Planck collaboration.

837
00:37:45,690 --> 00:37:49,018
I joined when it was about to be launched.

838
00:37:49,018 --> 00:37:50,540
(tense music)

839
00:37:50,540 --> 00:37:52,070
So basically you can think of Planck

840
00:37:52,070 --> 00:37:54,530
as a camera that has a lens

841
00:37:54,530 --> 00:37:57,880
of about one and a half to two meters in diameter.

842
00:37:57,880 --> 00:38:01,997
It has an array of about 50 detectors or so.

843
00:38:01,997 --> 00:38:04,664
(gentle music)

844
00:38:06,010 --> 00:38:09,480
While we were pleased with the devices on Planck,

845
00:38:09,480 --> 00:38:11,260
BICEP didn't have as much sensitivity

846
00:38:11,260 --> 00:38:12,623
as we ultimately wanted.

847
00:38:13,920 --> 00:38:18,360
We needed to increase the detectors from dozens to hundreds,

848
00:38:18,360 --> 00:38:20,550
to thousands, to tens of thousands.

849
00:38:20,550 --> 00:38:23,743
And the way to do that is using the same methods

850
00:38:23,743 --> 00:38:26,659
that we use to make computer chips.

851
00:38:26,659 --> 00:38:28,440
(gentle music)

852
00:38:28,440 --> 00:38:29,480
With a lithograph,

853
00:38:29,480 --> 00:38:32,727
the entire structure and reproduce them many, many times.

854
00:38:32,727 --> 00:38:35,120
And in fact, you don't wanna just reproduce the balometer,

855
00:38:35,120 --> 00:38:37,090
you wanna produce everything about it,

856
00:38:37,090 --> 00:38:40,820
how it couples to light, which we use a printed antenna,

857
00:38:40,820 --> 00:38:42,650
and how we select the frequencies.

858
00:38:42,650 --> 00:38:46,060
All this is just lithographed on the device itself.

859
00:38:46,060 --> 00:38:47,150
So you build an instrument,

860
00:38:47,150 --> 00:38:48,970
you measure the sky with it for a few years,

861
00:38:48,970 --> 00:38:52,010
you build more detectors, more sensitivity, more data,

862
00:38:52,010 --> 00:38:54,530
so you can improve the sensitivity faster.

863
00:38:54,530 --> 00:38:55,640
So that's been the pattern.

864
00:38:55,640 --> 00:38:57,953
There was BICEP1, then there was BICEP2,

865
00:38:57,953 --> 00:38:59,350
then there was Keck Array,

866
00:38:59,350 --> 00:39:01,820
but basically it's just continual arms race

867
00:39:01,820 --> 00:39:03,333
of improving sensitivities.

868
00:39:04,270 --> 00:39:07,594
Between 2010 and 2012,

869
00:39:07,594 --> 00:39:10,783
BICEP2 collected thousands of scans of the sky.

870
00:39:11,700 --> 00:39:15,230
BICEP was observing a very small part of the sky

871
00:39:15,230 --> 00:39:17,970
with as much sensitivity as they could.

872
00:39:17,970 --> 00:39:19,980
They chose the patch of the sky,

873
00:39:19,980 --> 00:39:22,483
which they thought would be the cleanest possible.

874
00:39:23,680 --> 00:39:25,950
During the same period of time,

875
00:39:25,950 --> 00:39:29,670
ESA's Planck spacecraft revolved once every minute,

876
00:39:29,670 --> 00:39:33,700
slowly scanning the entire cosmos over the months.

877
00:39:33,700 --> 00:39:36,367
(gentle music)

878
00:39:37,240 --> 00:39:38,530
The measurements that we take,

879
00:39:38,530 --> 00:39:41,820
they do not reveal things instantaneously.

880
00:39:41,820 --> 00:39:44,230
The data take years to acquire.

881
00:39:44,230 --> 00:39:47,252
They can take year or more to analyze.

882
00:39:47,252 --> 00:39:48,250
(gentle music)

883
00:39:48,250 --> 00:39:49,860
Now we have four scientists representing

884
00:39:49,860 --> 00:39:52,570
the device of two collaborations, John Kovac--

885
00:39:52,570 --> 00:39:54,710
People have a slightly ivory tower view

886
00:39:54,710 --> 00:39:56,430
of science sometimes.

887
00:39:56,430 --> 00:39:58,070
Like we all sit in the common room,

888
00:39:58,070 --> 00:40:01,010
smoking our pipes and being great chums with each other.

889
00:40:01,010 --> 00:40:03,960
And science can be fiercely competitive.

890
00:40:03,960 --> 00:40:06,110
People's careers depend on the results

891
00:40:06,110 --> 00:40:09,300
that you publish ahead of other people.

892
00:40:09,300 --> 00:40:11,270
So the theory of cosmic inflation,

893
00:40:11,270 --> 00:40:14,460
which attempts to explain the start of the big bang itself,

894
00:40:14,460 --> 00:40:16,100
predicts that the early universe will contain

895
00:40:16,100 --> 00:40:18,210
a background of gravitational waves

896
00:40:18,210 --> 00:40:21,960
that produce patterns of polarization called B-modes.

897
00:40:21,960 --> 00:40:23,610
Suddenly there was an announcement

898
00:40:23,610 --> 00:40:25,960
by the BICEP2 team claiming

899
00:40:25,960 --> 00:40:29,700
that they have observed primordial gravitational waves.

900
00:40:29,700 --> 00:40:31,830
Today were gonna be reporting the detection

901
00:40:31,830 --> 00:40:35,800
of B-mode polarization as seen by the BICEP2 telescope

902
00:40:35,800 --> 00:40:38,180
that matches very closely the predicted pattern.

903
00:40:38,180 --> 00:40:40,920
This was big news in our community.

904
00:40:40,920 --> 00:40:43,938
So many of us watched the results together.

905
00:40:43,938 --> 00:40:44,771
(laughing)

906
00:40:44,771 --> 00:40:45,660
This is amazing!

907
00:40:45,660 --> 00:40:47,750
You talk about it being thrilling.

908
00:40:47,750 --> 00:40:50,800
Maybe it was in a way, but it was also terrifying.

909
00:40:50,800 --> 00:40:52,280
Up here today are the co-leaders

910
00:40:52,280 --> 00:40:55,780
of the BICEP and Keck Array series of--

911
00:40:55,780 --> 00:40:59,860
Well, I think the first reaction was "wow." (chuckles)

912
00:40:59,860 --> 00:41:01,650
Major collaborators that you see in BICEP2

913
00:41:01,650 --> 00:41:02,483
over the past--

914
00:41:02,483 --> 00:41:05,270
Because it was presented as a clear cut case.

915
00:41:05,270 --> 00:41:07,200
UC San Diego, Brian Heating's group there, they're--

916
00:41:07,200 --> 00:41:09,340
There are considerable challenges

917
00:41:09,340 --> 00:41:12,440
to separating the E-modes and the B-modes accurately enough.

918
00:41:12,440 --> 00:41:15,040
We had to develop new mathematical techniques

919
00:41:15,040 --> 00:41:16,720
to allow us to do that.

920
00:41:16,720 --> 00:41:19,130
When we apply those techniques we started to be able

921
00:41:19,130 --> 00:41:22,390
to see a B-mode detected with statistical significance

922
00:41:22,390 --> 00:41:23,960
for the first time.

923
00:41:23,960 --> 00:41:26,020
And this was of course tremendously exciting.

924
00:41:26,020 --> 00:41:29,020
It was what we had been trying to do for all of these years.

925
00:41:29,020 --> 00:41:30,400
Pattern is very distinct.

926
00:41:30,400 --> 00:41:32,570
However, the signal is very small.

927
00:41:32,570 --> 00:41:34,830
And they said, we have found gravitational waves.

928
00:41:34,830 --> 00:41:38,310
This is yet another confirmational inflationary theory.

929
00:41:38,310 --> 00:41:39,780
Everything was great.

930
00:41:39,780 --> 00:41:43,380
We felt that the polarization pattern on the sky was real.

931
00:41:43,380 --> 00:41:45,187
As Clem Pryke would later say,

932
00:41:45,187 --> 00:41:48,100
"We instead of seeing a needle in a haystack,

933
00:41:48,100 --> 00:41:50,017
we observed what was," later he called,

934
00:41:50,017 --> 00:41:51,820
"a crowbar in a haystack."

935
00:41:51,820 --> 00:41:56,820
Okay, so this is the actual polarization pattern map

936
00:41:57,360 --> 00:41:59,856
as measured by the BICEP2 telescope.

937
00:41:59,856 --> 00:42:03,580
Think of it as little sticks indicating the direction

938
00:42:03,580 --> 00:42:05,980
and the magnitude of the polarization.

939
00:42:05,980 --> 00:42:08,183
The most reasonable interpretation is

940
00:42:08,183 --> 00:42:10,660
that it is gravity waves written

941
00:42:10,660 --> 00:42:12,480
in that micro background pattern.

942
00:42:12,480 --> 00:42:15,430
And those gravity waves come from the inflationary epoch

943
00:42:15,430 --> 00:42:18,518
at a tiny, tiny fraction of a second after the beginning.

944
00:42:18,518 --> 00:42:22,367
(audience applauding)

945
00:42:22,367 --> 00:42:24,950
(tense music)

946
00:42:29,240 --> 00:42:31,100
The BICEP team had made an announcement

947
00:42:31,100 --> 00:42:33,260
that suggested that the holy grail

948
00:42:33,260 --> 00:42:35,500
of signals had been found.

949
00:42:35,500 --> 00:42:38,920
One that would show for certain that inflation had occurred

950
00:42:38,920 --> 00:42:41,530
and that the big bang model was correct,

951
00:42:41,530 --> 00:42:43,130
but there were troubles brewing.

952
00:42:44,160 --> 00:42:45,480
But if other people have other data

953
00:42:45,480 --> 00:42:47,187
and they can go in and say,

954
00:42:47,187 --> 00:42:49,560
"actually, we don't see the same thing as you."

955
00:42:49,560 --> 00:42:50,760
That's the risk you run.

956
00:42:52,480 --> 00:42:55,700
As you may have gathered, if seems traditional now

957
00:42:55,700 --> 00:42:57,770
that each experiment is very secretive

958
00:42:57,770 --> 00:42:59,652
about what it's doing.

959
00:42:59,652 --> 00:43:01,140
(tense music)

960
00:43:01,140 --> 00:43:03,790
As soon as people started to look at the paper

961
00:43:03,790 --> 00:43:06,017
and at the details, they realized that,

962
00:43:06,017 --> 00:43:10,020
"Hmm, maybe there are some issues here."

963
00:43:10,020 --> 00:43:12,400
(tense music)

964
00:43:12,400 --> 00:43:16,670
Now we had only measured this at one frequency,

965
00:43:16,670 --> 00:43:19,230
basically where the CMB is brightest.

966
00:43:19,230 --> 00:43:22,100
Now it's possible that we would have contamination

967
00:43:22,100 --> 00:43:25,520
from our own galaxy from polarized dust.

968
00:43:25,520 --> 00:43:27,260
The issue is that we had the means,

969
00:43:27,260 --> 00:43:31,230
Planck had the means to measure the dust part of the signal.

970
00:43:31,230 --> 00:43:33,250
There were no measurements available

971
00:43:33,250 --> 00:43:37,700
to our team at the time of a brightness of polarized dust

972
00:43:37,700 --> 00:43:39,550
in these faint regions.

973
00:43:39,550 --> 00:43:42,435
the Planck satellite team had this data,

974
00:43:42,435 --> 00:43:45,036
but we didn't have access to it.

975
00:43:45,036 --> 00:43:47,200
(tense music)

976
00:43:47,200 --> 00:43:48,360
The BICEP team thought

977
00:43:48,360 --> 00:43:50,130
they had an agreement with ESA

978
00:43:50,130 --> 00:43:52,460
that the Planck team would provide them with data

979
00:43:52,460 --> 00:43:55,360
that would show the dust contribution to the BICEP signal.

980
00:43:57,091 --> 00:43:58,180
(tense music)

981
00:43:58,180 --> 00:44:00,640
But it's not the way it played out in the end.

982
00:44:00,640 --> 00:44:03,526
We did ask and they did not provide us the data

983
00:44:03,526 --> 00:44:05,960
that could be, A they didn't have it,

984
00:44:05,960 --> 00:44:07,700
B that maybe they did have the results

985
00:44:07,700 --> 00:44:09,180
and they were bluffing,

986
00:44:09,180 --> 00:44:12,660
C this wasn't something that they could agree upon

987
00:44:12,660 --> 00:44:13,951
on our time scale.

988
00:44:13,951 --> 00:44:16,840
(tense music)

989
00:44:16,840 --> 00:44:18,140
Well of course it was certainly not

990
00:44:18,140 --> 00:44:20,580
about destroying anybody or any group,

991
00:44:20,580 --> 00:44:22,693
it was about getting the good result.

992
00:44:23,968 --> 00:44:25,740
(tense music)

993
00:44:25,740 --> 00:44:27,810
Well, so the first thing that happened is

994
00:44:27,810 --> 00:44:31,690
the Planck team put out a paper on the polarization

995
00:44:31,690 --> 00:44:34,410
in the diffuse sky, including our region.

996
00:44:34,410 --> 00:44:37,930
And it showed indeed that the polarized emission

997
00:44:37,930 --> 00:44:42,027
from the galaxy was bigger than we had assumed from models.

998
00:44:43,860 --> 00:44:47,083
The signal that we saw turned out to be dust emission.

999
00:44:48,760 --> 00:44:51,380
The thing that clears up scientific disputes

1000
00:44:51,380 --> 00:44:53,163
and uncertainties is data.

1001
00:44:54,400 --> 00:44:57,430
In order to get a clean understanding of the problem,

1002
00:44:57,430 --> 00:44:59,740
you needed to use both sets of data,

1003
00:44:59,740 --> 00:45:01,590
you couldn't do it with Planck only,

1004
00:45:01,590 --> 00:45:03,490
you couldn't do it with BICEP only.

1005
00:45:03,490 --> 00:45:06,870
And so we very quickly decided

1006
00:45:06,870 --> 00:45:09,303
that we had to work together with their team.

1007
00:45:10,540 --> 00:45:12,610
The two teams joined forces

1008
00:45:12,610 --> 00:45:15,590
and together they published the results of what had happened

1009
00:45:15,590 --> 00:45:17,373
in this remarkable story.

1010
00:45:18,210 --> 00:45:20,800
They jointly told the world that BICEP

1011
00:45:20,800 --> 00:45:23,523
had not yet found evidence for inflation.

1012
00:45:24,410 --> 00:45:27,040
Well, I thought, "Oh man, that must hurt."

1013
00:45:27,040 --> 00:45:28,680
That was tough luck for them.

1014
00:45:28,680 --> 00:45:30,290
They were too eager.

1015
00:45:30,290 --> 00:45:31,650
It's a bit embarrassing perhaps,

1016
00:45:31,650 --> 00:45:34,720
but I think being a skeptic about any result

1017
00:45:34,720 --> 00:45:37,100
and getting independent confirmation,

1018
00:45:37,100 --> 00:45:38,330
that's how science works.

1019
00:45:38,330 --> 00:45:41,480
And you know, point here isn't how I feel.

1020
00:45:41,480 --> 00:45:45,320
The point is, how do we get to the best result?

1021
00:45:45,320 --> 00:45:48,697
I don't think I was particularly sorry for them

1022
00:45:48,697 --> 00:45:52,040
in the sense they did a wonderful job.

1023
00:45:52,040 --> 00:45:54,560
I was sorry because it wasn't true.

1024
00:45:54,560 --> 00:45:59,430
Because it would've been scientifically much more exciting

1025
00:45:59,430 --> 00:46:02,500
to actually have access to that signal

1026
00:46:02,500 --> 00:46:04,390
and therefore to inflation,

1027
00:46:04,390 --> 00:46:08,206
and to a new part of knowledge in the universe.

1028
00:46:08,206 --> 00:46:09,900
(tense music)

1029
00:46:09,900 --> 00:46:11,730
It is widely acknowledged

1030
00:46:11,730 --> 00:46:14,410
that the BICEP team did great science,

1031
00:46:14,410 --> 00:46:17,883
but at this time they were fooled by the galactic dust.

1032
00:46:19,450 --> 00:46:22,960
They made a mistake, but on the other hand,

1033
00:46:22,960 --> 00:46:26,150
they were the first to come to the verge

1034
00:46:26,150 --> 00:46:29,613
of possible discovery and still the best.

1035
00:46:30,690 --> 00:46:33,330
Theoretical scientists, like Andrei,

1036
00:46:33,330 --> 00:46:38,000
need experimental scientists like Jamie, Brian and Clem.

1037
00:46:38,000 --> 00:46:40,560
A scientific theory is of limited use

1038
00:46:40,560 --> 00:46:42,880
unless an experimenter can come along

1039
00:46:42,880 --> 00:46:45,490
and prove that a theory is correct.

1040
00:46:45,490 --> 00:46:47,943
And this is the story of the big bang.

1041
00:46:49,120 --> 00:46:51,720
Edwin Hubble proved Lemaitre right,

1042
00:46:51,720 --> 00:46:54,360
that the universe must be expanding.

1043
00:46:54,360 --> 00:46:57,340
Penzias And Wilson proved that theorists were right

1044
00:46:57,340 --> 00:47:00,300
when they found the cosmic microwave background.

1045
00:47:00,300 --> 00:47:03,670
But as we shall see, finding evidence for inflation

1046
00:47:03,670 --> 00:47:05,961
is still the key objective.

1047
00:47:05,961 --> 00:47:08,794
(exciting music)

1048
00:47:13,470 --> 00:47:15,840
I think the consensus today in a community is

1049
00:47:15,840 --> 00:47:19,500
that inflation is the best candidate for the phenomena,

1050
00:47:19,500 --> 00:47:21,010
the early part of the universe.

1051
00:47:21,010 --> 00:47:23,090
And so I think we should pursue this.

1052
00:47:23,090 --> 00:47:24,982
No question about it.

1053
00:47:24,982 --> 00:47:26,760
(upbeat music)

1054
00:47:26,760 --> 00:47:30,430
I'm involved in a project called the Simon's Observatory,

1055
00:47:30,430 --> 00:47:33,220
which is building a set of telescopes

1056
00:47:33,220 --> 00:47:35,663
that are going to be in the North of Chile.

1057
00:47:36,620 --> 00:47:39,530
So the Simon's Observatory is a large collaboration,

1058
00:47:39,530 --> 00:47:41,750
spanning all seven continents

1059
00:47:41,750 --> 00:47:44,650
of approximately 300 individual researchers

1060
00:47:44,650 --> 00:47:46,970
and about 45 institutions.

1061
00:47:46,970 --> 00:47:49,820
If you can't be in space, the two best sites are Chile

1062
00:47:49,820 --> 00:47:52,780
and the South Pole for looking at this CMB radiation.

1063
00:47:52,780 --> 00:47:54,230
It's 'cause they're very dry.

1064
00:47:55,400 --> 00:47:58,960
BICEP is also continuously pushing the envelope

1065
00:47:58,960 --> 00:48:01,720
on their experiments at the South Pole.

1066
00:48:01,720 --> 00:48:03,820
And both teams plan to build

1067
00:48:03,820 --> 00:48:06,220
a healthy competition between them.

1068
00:48:06,220 --> 00:48:08,870
So their goal is to compete with us head to head,

1069
00:48:08,870 --> 00:48:11,850
and we'll see who does the best.

1070
00:48:11,850 --> 00:48:16,630
The goal is to reach similar sensitivity to this radiation

1071
00:48:16,630 --> 00:48:18,380
and to these gravitational waves

1072
00:48:18,380 --> 00:48:20,820
from both of these locations on Earth.

1073
00:48:20,820 --> 00:48:22,690
I see it as being important

1074
00:48:23,670 --> 00:48:26,120
to have two complementary approaches

1075
00:48:26,120 --> 00:48:29,544
to such an important potential discovery.

1076
00:48:29,544 --> 00:48:31,820
(exciting music)

1077
00:48:31,820 --> 00:48:35,920
I think it's very good that people are collaborating

1078
00:48:35,920 --> 00:48:37,950
and sharing information.

1079
00:48:37,950 --> 00:48:40,200
I think that's the way science ought to work.

1080
00:48:41,890 --> 00:48:45,270
(upbeat music)

1081
00:48:45,270 --> 00:48:48,550
Best part about it is that no one can do it alone.

1082
00:48:48,550 --> 00:48:50,950
One of the powerful lessons of BICEP2 is

1083
00:48:50,950 --> 00:48:53,710
that it will take the village of all of cosmology

1084
00:48:53,710 --> 00:48:56,000
that we will rely on the confirmation

1085
00:48:56,000 --> 00:48:58,451
of sometimes our competitors.

1086
00:48:58,451 --> 00:49:00,260
(gentle music)

1087
00:49:00,260 --> 00:49:01,600
Looking down the horizon,

1088
00:49:01,600 --> 00:49:03,000
we can perhaps envision a day

1089
00:49:03,000 --> 00:49:05,540
where there'll just be one experiment.

1090
00:49:05,540 --> 00:49:08,160
So there is a concrete plan in the works

1091
00:49:08,160 --> 00:49:11,900
for the ultimate ground based CMB experiment,

1092
00:49:11,900 --> 00:49:14,290
and it's being called CMBS4.

1093
00:49:14,290 --> 00:49:15,910
The objective is to make observations

1094
00:49:15,910 --> 00:49:18,130
from both South Pole and from Chile

1095
00:49:18,130 --> 00:49:21,080
with apparatus somewhat similar to the current experiments,

1096
00:49:21,080 --> 00:49:22,800
but just a lot more of it.

1097
00:49:22,800 --> 00:49:25,223
And so it's kind of a mega experiment.

1098
00:49:26,840 --> 00:49:29,380
I'm sure that all the work that has been done so far,

1099
00:49:29,380 --> 00:49:31,030
including the one from BICEP,

1100
00:49:31,030 --> 00:49:34,260
will help in reaching that final goal.

1101
00:49:34,260 --> 00:49:36,300
(gentle music)

1102
00:49:36,300 --> 00:49:38,620
The big bang theory attempts to answer

1103
00:49:38,620 --> 00:49:41,083
the biggest question anyone can ask,

1104
00:49:42,207 --> 00:49:43,517
"Where do we come from?"

1105
00:49:45,240 --> 00:49:48,420
The theory has passed many challenging tests

1106
00:49:48,420 --> 00:49:52,023
and it is the best description of how our universe began.

1107
00:49:53,700 --> 00:49:56,620
We have to be prepared that all these dedicated efforts

1108
00:49:56,620 --> 00:49:59,903
may ultimately fall behind of the unknowable screen.

1109
00:50:00,975 --> 00:50:02,640
(gentle music)

1110
00:50:02,640 --> 00:50:05,750
It may be that there is simply a limit

1111
00:50:05,750 --> 00:50:08,740
to how much one can know about the earliest moments

1112
00:50:08,740 --> 00:50:11,375
of the creation of the universe.

1113
00:50:11,375 --> 00:50:13,250
(gentle music)

1114
00:50:13,250 --> 00:50:15,780
The way I say it is you imagine in your mind,

1115
00:50:15,780 --> 00:50:16,920
running the universe backwards

1116
00:50:16,920 --> 00:50:18,610
to where everything is compressed and compressed,

1117
00:50:18,610 --> 00:50:20,000
and hotter and hotter and hotter,

1118
00:50:20,000 --> 00:50:21,740
and when you run out of imagination,

1119
00:50:21,740 --> 00:50:23,750
that's what you call the big bang.

1120
00:50:23,750 --> 00:50:27,150
And we may push the imagination a little farther,

1121
00:50:27,150 --> 00:50:30,033
but eventually you probably still run out of imagination.

1122
00:50:31,944 --> 00:50:34,444
(tense music)

1123
00:50:58,316 --> 00:51:01,733
(bright twinkling music)

1124
00:51:02,597 --> 00:51:05,847
(gentle chiming music)