[Script Info]
Title: 
[Events]
Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text
Dialogue: 0,0:00:00.00,0:00:02.00,Default,,0000,0000,0000,,The universe
Dialogue: 0,0:00:02.00,0:00:04.00,Default,,0000,0000,0000,,is really big.
Dialogue: 0,0:00:04.00,0:00:07.00,Default,,0000,0000,0000,,We live in a galaxy, the Milky Way Galaxy.
Dialogue: 0,0:00:07.00,0:00:10.00,Default,,0000,0000,0000,,There are about a hundred billion stars in the Milky Way Galaxy.
Dialogue: 0,0:00:10.00,0:00:12.00,Default,,0000,0000,0000,,And if you take a camera
Dialogue: 0,0:00:12.00,0:00:14.00,Default,,0000,0000,0000,,and you point it at a random part of the sky,
Dialogue: 0,0:00:14.00,0:00:16.00,Default,,0000,0000,0000,,and you just keep the shutter open,
Dialogue: 0,0:00:16.00,0:00:19.00,Default,,0000,0000,0000,,as long as your camera is attached to the Hubble Space Telescope,
Dialogue: 0,0:00:19.00,0:00:21.00,Default,,0000,0000,0000,,it will see something like this.
Dialogue: 0,0:00:21.00,0:00:24.00,Default,,0000,0000,0000,,Every one of these little blobs
Dialogue: 0,0:00:24.00,0:00:26.00,Default,,0000,0000,0000,,is a galaxy roughly the size of our Milky Way --
Dialogue: 0,0:00:26.00,0:00:29.00,Default,,0000,0000,0000,,a hundred billion stars in each of those blobs.
Dialogue: 0,0:00:29.00,0:00:32.00,Default,,0000,0000,0000,,There are approximately a hundred billion galaxies
Dialogue: 0,0:00:32.00,0:00:34.00,Default,,0000,0000,0000,,in the observable universe.
Dialogue: 0,0:00:34.00,0:00:36.00,Default,,0000,0000,0000,,100 billion is the only number you need to know.
Dialogue: 0,0:00:36.00,0:00:39.00,Default,,0000,0000,0000,,The age of the universe, between now and the Big Bang,
Dialogue: 0,0:00:39.00,0:00:41.00,Default,,0000,0000,0000,,is a hundred billion in dog years.
Dialogue: 0,0:00:41.00,0:00:43.00,Default,,0000,0000,0000,,(Laughter)
Dialogue: 0,0:00:43.00,0:00:46.00,Default,,0000,0000,0000,,Which tells you something about our place in the universe.
Dialogue: 0,0:00:46.00,0:00:48.00,Default,,0000,0000,0000,,One thing you can do with a picture like this is simply admire it.
Dialogue: 0,0:00:48.00,0:00:50.00,Default,,0000,0000,0000,,It's extremely beautiful.
Dialogue: 0,0:00:50.00,0:00:53.00,Default,,0000,0000,0000,,I've often wondered, what is the evolutionary pressure
Dialogue: 0,0:00:53.00,0:00:56.00,Default,,0000,0000,0000,,that made our ancestors in the Veldt adapt and evolve
Dialogue: 0,0:00:56.00,0:00:58.00,Default,,0000,0000,0000,,to really enjoy pictures of galaxies
Dialogue: 0,0:00:58.00,0:01:00.00,Default,,0000,0000,0000,,when they didn't have any.
Dialogue: 0,0:01:00.00,0:01:02.00,Default,,0000,0000,0000,,But we would also like to understand it.
Dialogue: 0,0:01:02.00,0:01:06.00,Default,,0000,0000,0000,,As a cosmologist, I want to ask, why is the universe like this?
Dialogue: 0,0:01:06.00,0:01:09.00,Default,,0000,0000,0000,,One big clue we have is that the universe is changing with time.
Dialogue: 0,0:01:09.00,0:01:12.00,Default,,0000,0000,0000,,If you looked at one of these galaxies and measured its velocity,
Dialogue: 0,0:01:12.00,0:01:14.00,Default,,0000,0000,0000,,it would be moving away from you.
Dialogue: 0,0:01:14.00,0:01:16.00,Default,,0000,0000,0000,,And if you look at a galaxy even farther away,
Dialogue: 0,0:01:16.00,0:01:18.00,Default,,0000,0000,0000,,it would be moving away faster.
Dialogue: 0,0:01:18.00,0:01:20.00,Default,,0000,0000,0000,,So we say the universe is expanding.
Dialogue: 0,0:01:20.00,0:01:22.00,Default,,0000,0000,0000,,What that means, of course, is that, in the past,
Dialogue: 0,0:01:22.00,0:01:24.00,Default,,0000,0000,0000,,things were closer together.
Dialogue: 0,0:01:24.00,0:01:26.00,Default,,0000,0000,0000,,In the past, the universe was more dense,
Dialogue: 0,0:01:26.00,0:01:28.00,Default,,0000,0000,0000,,and it was also hotter.
Dialogue: 0,0:01:28.00,0:01:30.00,Default,,0000,0000,0000,,If you squeeze things together, the temperature goes up.
Dialogue: 0,0:01:30.00,0:01:32.00,Default,,0000,0000,0000,,That kind of makes sense to us.
Dialogue: 0,0:01:32.00,0:01:34.00,Default,,0000,0000,0000,,The thing that doesn't make sense to us as much
Dialogue: 0,0:01:34.00,0:01:37.00,Default,,0000,0000,0000,,is that the universe, at early times, near the Big Bang,
Dialogue: 0,0:01:37.00,0:01:39.00,Default,,0000,0000,0000,,was also very, very smooth.
Dialogue: 0,0:01:39.00,0:01:41.00,Default,,0000,0000,0000,,You might think that that's not a surprise.
Dialogue: 0,0:01:41.00,0:01:43.00,Default,,0000,0000,0000,,The air in this room is very smooth.
Dialogue: 0,0:01:43.00,0:01:46.00,Default,,0000,0000,0000,,You might say, "Well, maybe things just smoothed themselves out."
Dialogue: 0,0:01:46.00,0:01:49.00,Default,,0000,0000,0000,,But the conditions near the Big Bang are very, very different
Dialogue: 0,0:01:49.00,0:01:51.00,Default,,0000,0000,0000,,than the conditions of the air in this room.
Dialogue: 0,0:01:51.00,0:01:53.00,Default,,0000,0000,0000,,In particular, things were a lot denser.
Dialogue: 0,0:01:53.00,0:01:55.00,Default,,0000,0000,0000,,The gravitational pull of things
Dialogue: 0,0:01:55.00,0:01:57.00,Default,,0000,0000,0000,,was a lot stronger near the Big Bang.
Dialogue: 0,0:01:57.00,0:01:59.00,Default,,0000,0000,0000,,What you have to think about
Dialogue: 0,0:01:59.00,0:02:01.00,Default,,0000,0000,0000,,is we have a universe with a hundred billion galaxies,
Dialogue: 0,0:02:01.00,0:02:03.00,Default,,0000,0000,0000,,a hundred billion stars each.
Dialogue: 0,0:02:03.00,0:02:06.00,Default,,0000,0000,0000,,At early times, those hundred billion galaxies
Dialogue: 0,0:02:06.00,0:02:09.00,Default,,0000,0000,0000,,were squeezed into a region about this big --
Dialogue: 0,0:02:09.00,0:02:11.00,Default,,0000,0000,0000,,literally -- at early times.
Dialogue: 0,0:02:11.00,0:02:13.00,Default,,0000,0000,0000,,And you have to imagine doing that squeezing
Dialogue: 0,0:02:13.00,0:02:15.00,Default,,0000,0000,0000,,without any imperfections,
Dialogue: 0,0:02:15.00,0:02:17.00,Default,,0000,0000,0000,,without any little spots
Dialogue: 0,0:02:17.00,0:02:19.00,Default,,0000,0000,0000,,where there were a few more atoms than somewhere else.
Dialogue: 0,0:02:19.00,0:02:22.00,Default,,0000,0000,0000,,Because if there had been, they would have collapsed under the gravitational pull
Dialogue: 0,0:02:22.00,0:02:24.00,Default,,0000,0000,0000,,into a huge black hole.
Dialogue: 0,0:02:24.00,0:02:27.00,Default,,0000,0000,0000,,Keeping the universe very, very smooth at early times
Dialogue: 0,0:02:27.00,0:02:29.00,Default,,0000,0000,0000,,is not easy; it's a delicate arrangement.
Dialogue: 0,0:02:29.00,0:02:31.00,Default,,0000,0000,0000,,It's a clue
Dialogue: 0,0:02:31.00,0:02:33.00,Default,,0000,0000,0000,,that the early universe is not chosen randomly.
Dialogue: 0,0:02:33.00,0:02:35.00,Default,,0000,0000,0000,,There is something that made it that way.
Dialogue: 0,0:02:35.00,0:02:37.00,Default,,0000,0000,0000,,We would like to know what.
Dialogue: 0,0:02:37.00,0:02:40.00,Default,,0000,0000,0000,,So part of our understanding of this was given to us by Ludwig Boltzmann,
Dialogue: 0,0:02:40.00,0:02:43.00,Default,,0000,0000,0000,,an Austrian physicist in the 19th century.
Dialogue: 0,0:02:43.00,0:02:46.00,Default,,0000,0000,0000,,And Boltzmann's contribution was that he helped us understand entropy.
Dialogue: 0,0:02:46.00,0:02:48.00,Default,,0000,0000,0000,,You've heard of entropy.
Dialogue: 0,0:02:48.00,0:02:51.00,Default,,0000,0000,0000,,It's the randomness, the disorder, the chaoticness of some systems.
Dialogue: 0,0:02:51.00,0:02:53.00,Default,,0000,0000,0000,,Boltzmann gave us a formula --
Dialogue: 0,0:02:53.00,0:02:55.00,Default,,0000,0000,0000,,engraved on his tombstone now --
Dialogue: 0,0:02:55.00,0:02:57.00,Default,,0000,0000,0000,,that really quantifies what entropy is.
Dialogue: 0,0:02:57.00,0:02:59.00,Default,,0000,0000,0000,,And it's basically just saying
Dialogue: 0,0:02:59.00,0:03:01.00,Default,,0000,0000,0000,,that entropy is the number of ways
Dialogue: 0,0:03:01.00,0:03:04.00,Default,,0000,0000,0000,,we can rearrange the constituents of a system so that you don't notice,
Dialogue: 0,0:03:04.00,0:03:06.00,Default,,0000,0000,0000,,so that macroscopically it looks the same.
Dialogue: 0,0:03:06.00,0:03:08.00,Default,,0000,0000,0000,,If you have the air in this room,
Dialogue: 0,0:03:08.00,0:03:11.00,Default,,0000,0000,0000,,you don't notice each individual atom.
Dialogue: 0,0:03:11.00,0:03:13.00,Default,,0000,0000,0000,,A low entropy configuration
Dialogue: 0,0:03:13.00,0:03:15.00,Default,,0000,0000,0000,,is one in which there's only a few arrangements that look that way.
Dialogue: 0,0:03:15.00,0:03:17.00,Default,,0000,0000,0000,,A high entropy arrangement
Dialogue: 0,0:03:17.00,0:03:19.00,Default,,0000,0000,0000,,is one that there are many arrangements that look that way.
Dialogue: 0,0:03:19.00,0:03:21.00,Default,,0000,0000,0000,,This is a crucially important insight
Dialogue: 0,0:03:21.00,0:03:23.00,Default,,0000,0000,0000,,because it helps us explain
Dialogue: 0,0:03:23.00,0:03:25.00,Default,,0000,0000,0000,,the second law of thermodynamics --
Dialogue: 0,0:03:25.00,0:03:28.00,Default,,0000,0000,0000,,the law that says that entropy increases in the universe,
Dialogue: 0,0:03:28.00,0:03:30.00,Default,,0000,0000,0000,,or in some isolated bit of the universe.
Dialogue: 0,0:03:30.00,0:03:32.00,Default,,0000,0000,0000,,The reason why entropy increases
Dialogue: 0,0:03:32.00,0:03:35.00,Default,,0000,0000,0000,,is simply because there are many more ways
Dialogue: 0,0:03:35.00,0:03:37.00,Default,,0000,0000,0000,,to be high entropy than to be low entropy.
Dialogue: 0,0:03:37.00,0:03:39.00,Default,,0000,0000,0000,,That's a wonderful insight,
Dialogue: 0,0:03:39.00,0:03:41.00,Default,,0000,0000,0000,,but it leaves something out.
Dialogue: 0,0:03:41.00,0:03:43.00,Default,,0000,0000,0000,,This insight that entropy increases, by the way,
Dialogue: 0,0:03:43.00,0:03:46.00,Default,,0000,0000,0000,,is what's behind what we call the arrow of time,
Dialogue: 0,0:03:46.00,0:03:48.00,Default,,0000,0000,0000,,the difference between the past and the future.
Dialogue: 0,0:03:48.00,0:03:50.00,Default,,0000,0000,0000,,Every difference that there is
Dialogue: 0,0:03:50.00,0:03:52.00,Default,,0000,0000,0000,,between the past and the future
Dialogue: 0,0:03:52.00,0:03:54.00,Default,,0000,0000,0000,,is because entropy is increasing --
Dialogue: 0,0:03:54.00,0:03:57.00,Default,,0000,0000,0000,,the fact that you can remember the past, but not the future.
Dialogue: 0,0:03:57.00,0:04:00.00,Default,,0000,0000,0000,,The fact that you are born, and then you live, and then you die,
Dialogue: 0,0:04:00.00,0:04:02.00,Default,,0000,0000,0000,,always in that order,
Dialogue: 0,0:04:02.00,0:04:04.00,Default,,0000,0000,0000,,that's because entropy is increasing.
Dialogue: 0,0:04:04.00,0:04:06.00,Default,,0000,0000,0000,,Boltzmann explained that if you start with low entropy,
Dialogue: 0,0:04:06.00,0:04:08.00,Default,,0000,0000,0000,,it's very natural for it to increase
Dialogue: 0,0:04:08.00,0:04:11.00,Default,,0000,0000,0000,,because there's more ways to be high entropy.
Dialogue: 0,0:04:11.00,0:04:13.00,Default,,0000,0000,0000,,What he didn't explain
Dialogue: 0,0:04:13.00,0:04:16.00,Default,,0000,0000,0000,,was why the entropy was ever low in the first place.
Dialogue: 0,0:04:16.00,0:04:18.00,Default,,0000,0000,0000,,The fact that the entropy of the universe was low
Dialogue: 0,0:04:18.00,0:04:20.00,Default,,0000,0000,0000,,was a reflection of the fact
Dialogue: 0,0:04:20.00,0:04:22.00,Default,,0000,0000,0000,,that the early universe was very, very smooth.
Dialogue: 0,0:04:22.00,0:04:24.00,Default,,0000,0000,0000,,We'd like to understand that.
Dialogue: 0,0:04:24.00,0:04:26.00,Default,,0000,0000,0000,,That's our job as cosmologists.
Dialogue: 0,0:04:26.00,0:04:28.00,Default,,0000,0000,0000,,Unfortunately, it's actually not a problem
Dialogue: 0,0:04:28.00,0:04:30.00,Default,,0000,0000,0000,,that we've been giving enough attention to.
Dialogue: 0,0:04:30.00,0:04:32.00,Default,,0000,0000,0000,,It's not one of the first things people would say,
Dialogue: 0,0:04:32.00,0:04:34.00,Default,,0000,0000,0000,,if you asked a modern cosmologist,
Dialogue: 0,0:04:34.00,0:04:36.00,Default,,0000,0000,0000,,"What are the problems we're trying to address?"
Dialogue: 0,0:04:36.00,0:04:38.00,Default,,0000,0000,0000,,One of the people who did understand that this was a problem
Dialogue: 0,0:04:38.00,0:04:40.00,Default,,0000,0000,0000,,was Richard Feynman.
Dialogue: 0,0:04:40.00,0:04:42.00,Default,,0000,0000,0000,,50 years ago, he gave a series of a bunch of different lectures.
Dialogue: 0,0:04:42.00,0:04:44.00,Default,,0000,0000,0000,,He gave the popular lectures
Dialogue: 0,0:04:44.00,0:04:46.00,Default,,0000,0000,0000,,that became "The Character of Physical Law."
Dialogue: 0,0:04:46.00,0:04:48.00,Default,,0000,0000,0000,,He gave lectures to Caltech undergrads
Dialogue: 0,0:04:48.00,0:04:50.00,Default,,0000,0000,0000,,that became "The Feynman Lectures on Physics."
Dialogue: 0,0:04:50.00,0:04:52.00,Default,,0000,0000,0000,,He gave lectures to Caltech graduate students
Dialogue: 0,0:04:52.00,0:04:54.00,Default,,0000,0000,0000,,that became "The Feynman Lectures on Gravitation."
Dialogue: 0,0:04:54.00,0:04:57.00,Default,,0000,0000,0000,,In every one of these books, every one of these sets of lectures,
Dialogue: 0,0:04:57.00,0:04:59.00,Default,,0000,0000,0000,,he emphasized this puzzle:
Dialogue: 0,0:04:59.00,0:05:02.00,Default,,0000,0000,0000,,Why did the early universe have such a small entropy?
Dialogue: 0,0:05:02.00,0:05:04.00,Default,,0000,0000,0000,,So he says -- I'm not going to do the accent --
Dialogue: 0,0:05:04.00,0:05:07.00,Default,,0000,0000,0000,,he says, "For some reason, the universe, at one time,
Dialogue: 0,0:05:07.00,0:05:10.00,Default,,0000,0000,0000,,had a very low entropy for its energy content,
Dialogue: 0,0:05:10.00,0:05:12.00,Default,,0000,0000,0000,,and since then the entropy has increased.
Dialogue: 0,0:05:12.00,0:05:15.00,Default,,0000,0000,0000,,The arrow of time cannot be completely understood
Dialogue: 0,0:05:15.00,0:05:18.00,Default,,0000,0000,0000,,until the mystery of the beginnings of the history of the universe
Dialogue: 0,0:05:18.00,0:05:20.00,Default,,0000,0000,0000,,are reduced still further
Dialogue: 0,0:05:20.00,0:05:22.00,Default,,0000,0000,0000,,from speculation to understanding."
Dialogue: 0,0:05:22.00,0:05:24.00,Default,,0000,0000,0000,,So that's our job.
Dialogue: 0,0:05:24.00,0:05:26.00,Default,,0000,0000,0000,,We want to know -- this is 50 years ago, "Surely," you're thinking,
Dialogue: 0,0:05:26.00,0:05:28.00,Default,,0000,0000,0000,,"we've figured it out by now."
Dialogue: 0,0:05:28.00,0:05:30.00,Default,,0000,0000,0000,,It's not true that we've figured it out by now.
Dialogue: 0,0:05:30.00,0:05:32.00,Default,,0000,0000,0000,,The reason the problem has gotten worse,
Dialogue: 0,0:05:32.00,0:05:34.00,Default,,0000,0000,0000,,rather than better,
Dialogue: 0,0:05:34.00,0:05:36.00,Default,,0000,0000,0000,,is because in 1998
Dialogue: 0,0:05:36.00,0:05:39.00,Default,,0000,0000,0000,,we learned something crucial about the universe that we didn't know before.
Dialogue: 0,0:05:39.00,0:05:41.00,Default,,0000,0000,0000,,We learned that it's accelerating.
Dialogue: 0,0:05:41.00,0:05:43.00,Default,,0000,0000,0000,,The universe is not only expanding.
Dialogue: 0,0:05:43.00,0:05:45.00,Default,,0000,0000,0000,,If you look at the galaxy, it's moving away.
Dialogue: 0,0:05:45.00,0:05:47.00,Default,,0000,0000,0000,,If you come back a billion years later and look at it again,
Dialogue: 0,0:05:47.00,0:05:50.00,Default,,0000,0000,0000,,it will be moving away faster.
Dialogue: 0,0:05:50.00,0:05:53.00,Default,,0000,0000,0000,,Individual galaxies are speeding away from us faster and faster
Dialogue: 0,0:05:53.00,0:05:55.00,Default,,0000,0000,0000,,so we say the universe is accelerating.
Dialogue: 0,0:05:55.00,0:05:57.00,Default,,0000,0000,0000,,Unlike the low entropy of the early universe,
Dialogue: 0,0:05:57.00,0:05:59.00,Default,,0000,0000,0000,,even though we don't know the answer for this,
Dialogue: 0,0:05:59.00,0:06:01.00,Default,,0000,0000,0000,,we at least have a good theory that can explain it,
Dialogue: 0,0:06:01.00,0:06:03.00,Default,,0000,0000,0000,,if that theory is right,
Dialogue: 0,0:06:03.00,0:06:05.00,Default,,0000,0000,0000,,and that's the theory of dark energy.
Dialogue: 0,0:06:05.00,0:06:08.00,Default,,0000,0000,0000,,It's just the idea that empty space itself has energy.
Dialogue: 0,0:06:08.00,0:06:11.00,Default,,0000,0000,0000,,In every little cubic centimeter of space,
Dialogue: 0,0:06:11.00,0:06:13.00,Default,,0000,0000,0000,,whether or not there's stuff,
Dialogue: 0,0:06:13.00,0:06:15.00,Default,,0000,0000,0000,,whether or not there's particles, matter, radiation or whatever,
Dialogue: 0,0:06:15.00,0:06:18.00,Default,,0000,0000,0000,,there's still energy, even in the space itself.
Dialogue: 0,0:06:18.00,0:06:20.00,Default,,0000,0000,0000,,And this energy, according to Einstein,
Dialogue: 0,0:06:20.00,0:06:23.00,Default,,0000,0000,0000,,exerts a push on the universe.
Dialogue: 0,0:06:23.00,0:06:25.00,Default,,0000,0000,0000,,It is a perpetual impulse
Dialogue: 0,0:06:25.00,0:06:27.00,Default,,0000,0000,0000,,that pushes galaxies apart from each other.
Dialogue: 0,0:06:27.00,0:06:30.00,Default,,0000,0000,0000,,Because dark energy, unlike matter or radiation,
Dialogue: 0,0:06:30.00,0:06:33.00,Default,,0000,0000,0000,,does not dilute away as the universe expands.
Dialogue: 0,0:06:33.00,0:06:35.00,Default,,0000,0000,0000,,The amount of energy in each cubic centimeter
Dialogue: 0,0:06:35.00,0:06:37.00,Default,,0000,0000,0000,,remains the same,
Dialogue: 0,0:06:37.00,0:06:39.00,Default,,0000,0000,0000,,even as the universe gets bigger and bigger.
Dialogue: 0,0:06:39.00,0:06:42.00,Default,,0000,0000,0000,,This has crucial implications
Dialogue: 0,0:06:42.00,0:06:45.00,Default,,0000,0000,0000,,for what the universe is going to do in the future.
Dialogue: 0,0:06:45.00,0:06:47.00,Default,,0000,0000,0000,,For one thing, the universe will expand forever.
Dialogue: 0,0:06:47.00,0:06:49.00,Default,,0000,0000,0000,,Back when I was your age,
Dialogue: 0,0:06:49.00,0:06:51.00,Default,,0000,0000,0000,,we didn't know what the universe was going to do.
Dialogue: 0,0:06:51.00,0:06:54.00,Default,,0000,0000,0000,,Some people thought that the universe would recollapse in the future.
Dialogue: 0,0:06:54.00,0:06:56.00,Default,,0000,0000,0000,,Einstein was fond of this idea.
Dialogue: 0,0:06:56.00,0:06:59.00,Default,,0000,0000,0000,,But if there's dark energy, and the dark energy does not go away,
Dialogue: 0,0:06:59.00,0:07:02.00,Default,,0000,0000,0000,,the universe is just going to keep expanding forever and ever and ever.
Dialogue: 0,0:07:02.00,0:07:04.00,Default,,0000,0000,0000,,14 billion years in the past,
Dialogue: 0,0:07:04.00,0:07:06.00,Default,,0000,0000,0000,,100 billion dog years,
Dialogue: 0,0:07:06.00,0:07:09.00,Default,,0000,0000,0000,,but an infinite number of years into the future.
Dialogue: 0,0:07:09.00,0:07:12.00,Default,,0000,0000,0000,,Meanwhile, for all intents and purposes,
Dialogue: 0,0:07:12.00,0:07:14.00,Default,,0000,0000,0000,,space looks finite to us.
Dialogue: 0,0:07:14.00,0:07:16.00,Default,,0000,0000,0000,,Space may be finite or infinite,
Dialogue: 0,0:07:16.00,0:07:18.00,Default,,0000,0000,0000,,but because the universe is accelerating,
Dialogue: 0,0:07:18.00,0:07:20.00,Default,,0000,0000,0000,,there are parts of it we cannot see
Dialogue: 0,0:07:20.00,0:07:22.00,Default,,0000,0000,0000,,and never will see.
Dialogue: 0,0:07:22.00,0:07:24.00,Default,,0000,0000,0000,,There's a finite region of space that we have access to,
Dialogue: 0,0:07:24.00,0:07:26.00,Default,,0000,0000,0000,,surrounded by a horizon.
Dialogue: 0,0:07:26.00,0:07:28.00,Default,,0000,0000,0000,,So even though time goes on forever,
Dialogue: 0,0:07:28.00,0:07:30.00,Default,,0000,0000,0000,,space is limited to us.
Dialogue: 0,0:07:30.00,0:07:33.00,Default,,0000,0000,0000,,Finally, empty space has a temperature.
Dialogue: 0,0:07:33.00,0:07:35.00,Default,,0000,0000,0000,,In the 1970s, Stephen Hawking told us
Dialogue: 0,0:07:35.00,0:07:37.00,Default,,0000,0000,0000,,that a black hole, even though you think it's black,
Dialogue: 0,0:07:37.00,0:07:39.00,Default,,0000,0000,0000,,it actually emits radiation
Dialogue: 0,0:07:39.00,0:07:41.00,Default,,0000,0000,0000,,when you take into account quantum mechanics.
Dialogue: 0,0:07:41.00,0:07:44.00,Default,,0000,0000,0000,,The curvature of space-time around the black hole
Dialogue: 0,0:07:44.00,0:07:47.00,Default,,0000,0000,0000,,brings to life the quantum mechanical fluctuation,
Dialogue: 0,0:07:47.00,0:07:49.00,Default,,0000,0000,0000,,and the black hole radiates.
Dialogue: 0,0:07:49.00,0:07:52.00,Default,,0000,0000,0000,,A precisely similar calculation by Hawking and Gary Gibbons
Dialogue: 0,0:07:52.00,0:07:55.00,Default,,0000,0000,0000,,showed that if you have dark energy in empty space,
Dialogue: 0,0:07:55.00,0:07:58.00,Default,,0000,0000,0000,,then the whole universe radiates.
Dialogue: 0,0:07:58.00,0:08:00.00,Default,,0000,0000,0000,,The energy of empty space
Dialogue: 0,0:08:00.00,0:08:02.00,Default,,0000,0000,0000,,brings to life quantum fluctuations.
Dialogue: 0,0:08:02.00,0:08:04.00,Default,,0000,0000,0000,,And so even though the universe will last forever,
Dialogue: 0,0:08:04.00,0:08:07.00,Default,,0000,0000,0000,,and ordinary matter and radiation will dilute away,
Dialogue: 0,0:08:07.00,0:08:09.00,Default,,0000,0000,0000,,there will always be some radiation,
Dialogue: 0,0:08:09.00,0:08:11.00,Default,,0000,0000,0000,,some thermal fluctuations,
Dialogue: 0,0:08:11.00,0:08:13.00,Default,,0000,0000,0000,,even in empty space.
Dialogue: 0,0:08:13.00,0:08:15.00,Default,,0000,0000,0000,,So what this means
Dialogue: 0,0:08:15.00,0:08:17.00,Default,,0000,0000,0000,,is that the universe is like a box of gas
Dialogue: 0,0:08:17.00,0:08:19.00,Default,,0000,0000,0000,,that lasts forever.
Dialogue: 0,0:08:19.00,0:08:21.00,Default,,0000,0000,0000,,Well what is the implication of that?
Dialogue: 0,0:08:21.00,0:08:24.00,Default,,0000,0000,0000,,That implication was studied by Boltzmann back in the 19th century.
Dialogue: 0,0:08:24.00,0:08:27.00,Default,,0000,0000,0000,,He said, well, entropy increases
Dialogue: 0,0:08:27.00,0:08:29.00,Default,,0000,0000,0000,,because there are many, many more ways
Dialogue: 0,0:08:29.00,0:08:32.00,Default,,0000,0000,0000,,for the universe to be high entropy, rather than low entropy.
Dialogue: 0,0:08:32.00,0:08:35.00,Default,,0000,0000,0000,,But that's a probabilistic statement.
Dialogue: 0,0:08:35.00,0:08:37.00,Default,,0000,0000,0000,,It will probably increase,
Dialogue: 0,0:08:37.00,0:08:39.00,Default,,0000,0000,0000,,and the probability is enormously huge.
Dialogue: 0,0:08:39.00,0:08:41.00,Default,,0000,0000,0000,,It's not something you have to worry about --
Dialogue: 0,0:08:41.00,0:08:45.00,Default,,0000,0000,0000,,the air in this room all gathering over one part of the room and suffocating us.
Dialogue: 0,0:08:45.00,0:08:47.00,Default,,0000,0000,0000,,It's very, very unlikely.
Dialogue: 0,0:08:47.00,0:08:49.00,Default,,0000,0000,0000,,Except if they locked the doors
Dialogue: 0,0:08:49.00,0:08:51.00,Default,,0000,0000,0000,,and kept us here literally forever,
Dialogue: 0,0:08:51.00,0:08:53.00,Default,,0000,0000,0000,,that would happen.
Dialogue: 0,0:08:53.00,0:08:55.00,Default,,0000,0000,0000,,Everything that is allowed,
Dialogue: 0,0:08:55.00,0:08:58.00,Default,,0000,0000,0000,,every configuration that is allowed to be obtained by the molecules in this room,
Dialogue: 0,0:08:58.00,0:09:00.00,Default,,0000,0000,0000,,would eventually be obtained.
Dialogue: 0,0:09:00.00,0:09:03.00,Default,,0000,0000,0000,,So Boltzmann says, look, you could start with a universe
Dialogue: 0,0:09:03.00,0:09:05.00,Default,,0000,0000,0000,,that was in thermal equilibrium.
Dialogue: 0,0:09:05.00,0:09:08.00,Default,,0000,0000,0000,,He didn't know about the Big Bang. He didn't know about the expansion of the universe.
Dialogue: 0,0:09:08.00,0:09:11.00,Default,,0000,0000,0000,,He thought that space and time were explained by Isaac Newton --
Dialogue: 0,0:09:11.00,0:09:13.00,Default,,0000,0000,0000,,they were absolute; they just stuck there forever.
Dialogue: 0,0:09:13.00,0:09:15.00,Default,,0000,0000,0000,,So his idea of a natural universe
Dialogue: 0,0:09:15.00,0:09:18.00,Default,,0000,0000,0000,,was one in which the air molecules were just spread out evenly everywhere --
Dialogue: 0,0:09:18.00,0:09:20.00,Default,,0000,0000,0000,,the everything molecules.
Dialogue: 0,0:09:20.00,0:09:23.00,Default,,0000,0000,0000,,But if you're Boltzmann, you know that if you wait long enough,
Dialogue: 0,0:09:23.00,0:09:26.00,Default,,0000,0000,0000,,the random fluctuations of those molecules
Dialogue: 0,0:09:26.00,0:09:28.00,Default,,0000,0000,0000,,will occasionally bring them
Dialogue: 0,0:09:28.00,0:09:30.00,Default,,0000,0000,0000,,into lower entropy configurations.
Dialogue: 0,0:09:30.00,0:09:32.00,Default,,0000,0000,0000,,And then, of course, in the natural course of things,
Dialogue: 0,0:09:32.00,0:09:34.00,Default,,0000,0000,0000,,they will expand back.
Dialogue: 0,0:09:34.00,0:09:36.00,Default,,0000,0000,0000,,So it's not that entropy must always increase --
Dialogue: 0,0:09:36.00,0:09:39.00,Default,,0000,0000,0000,,you can get fluctuations into lower entropy,
Dialogue: 0,0:09:39.00,0:09:41.00,Default,,0000,0000,0000,,more organized situations.
Dialogue: 0,0:09:41.00,0:09:43.00,Default,,0000,0000,0000,,Well if that's true,
Dialogue: 0,0:09:43.00,0:09:45.00,Default,,0000,0000,0000,,Boltzmann then goes onto invent
Dialogue: 0,0:09:45.00,0:09:47.00,Default,,0000,0000,0000,,two very modern-sounding ideas --
Dialogue: 0,0:09:47.00,0:09:50.00,Default,,0000,0000,0000,,the multiverse and the anthropic principle.
Dialogue: 0,0:09:50.00,0:09:52.00,Default,,0000,0000,0000,,He says, the problem with thermal equilibrium
Dialogue: 0,0:09:52.00,0:09:54.00,Default,,0000,0000,0000,,is that we can't live there.
Dialogue: 0,0:09:54.00,0:09:57.00,Default,,0000,0000,0000,,Remember, life itself depends on the arrow of time.
Dialogue: 0,0:09:57.00,0:09:59.00,Default,,0000,0000,0000,,We would not be able to process information,
Dialogue: 0,0:09:59.00,0:10:01.00,Default,,0000,0000,0000,,metabolize, walk and talk,
Dialogue: 0,0:10:01.00,0:10:03.00,Default,,0000,0000,0000,,if we lived in thermal equilibrium.
Dialogue: 0,0:10:03.00,0:10:05.00,Default,,0000,0000,0000,,So if you imagine a very, very big universe,
Dialogue: 0,0:10:05.00,0:10:07.00,Default,,0000,0000,0000,,an infinitely big universe,
Dialogue: 0,0:10:07.00,0:10:09.00,Default,,0000,0000,0000,,with randomly bumping into each other particles,
Dialogue: 0,0:10:09.00,0:10:12.00,Default,,0000,0000,0000,,there will occasionally be small fluctuations in the lower entropy states,
Dialogue: 0,0:10:12.00,0:10:14.00,Default,,0000,0000,0000,,and then they relax back.
Dialogue: 0,0:10:14.00,0:10:16.00,Default,,0000,0000,0000,,But there will also be large fluctuations.
Dialogue: 0,0:10:16.00,0:10:18.00,Default,,0000,0000,0000,,Occasionally, you will make a planet
Dialogue: 0,0:10:18.00,0:10:20.00,Default,,0000,0000,0000,,or a star or a galaxy
Dialogue: 0,0:10:20.00,0:10:22.00,Default,,0000,0000,0000,,or a hundred billion galaxies.
Dialogue: 0,0:10:22.00,0:10:24.00,Default,,0000,0000,0000,,So Boltzmann says,
Dialogue: 0,0:10:24.00,0:10:27.00,Default,,0000,0000,0000,,we will only live in the part of the multiverse,
Dialogue: 0,0:10:27.00,0:10:30.00,Default,,0000,0000,0000,,in the part of this infinitely big set of fluctuating particles,
Dialogue: 0,0:10:30.00,0:10:32.00,Default,,0000,0000,0000,,where life is possible.
Dialogue: 0,0:10:32.00,0:10:34.00,Default,,0000,0000,0000,,That's the region where entropy is low.
Dialogue: 0,0:10:34.00,0:10:37.00,Default,,0000,0000,0000,,Maybe our universe is just one of those things
Dialogue: 0,0:10:37.00,0:10:39.00,Default,,0000,0000,0000,,that happens from time to time.
Dialogue: 0,0:10:39.00,0:10:41.00,Default,,0000,0000,0000,,Now your homework assignment
Dialogue: 0,0:10:41.00,0:10:43.00,Default,,0000,0000,0000,,is to really think about this, to contemplate what it means.
Dialogue: 0,0:10:43.00,0:10:45.00,Default,,0000,0000,0000,,Carl Sagan once famously said
Dialogue: 0,0:10:45.00,0:10:47.00,Default,,0000,0000,0000,,that "in order to make an apple pie,
Dialogue: 0,0:10:47.00,0:10:50.00,Default,,0000,0000,0000,,you must first invent the universe."
Dialogue: 0,0:10:50.00,0:10:52.00,Default,,0000,0000,0000,,But he was not right.
Dialogue: 0,0:10:52.00,0:10:55.00,Default,,0000,0000,0000,,In Boltzmann's scenario, if you want to make an apple pie,
Dialogue: 0,0:10:55.00,0:10:58.00,Default,,0000,0000,0000,,you just wait for the random motion of atoms
Dialogue: 0,0:10:58.00,0:11:00.00,Default,,0000,0000,0000,,to make you an apple pie.
Dialogue: 0,0:11:00.00,0:11:02.00,Default,,0000,0000,0000,,That will happen much more frequently
Dialogue: 0,0:11:02.00,0:11:04.00,Default,,0000,0000,0000,,than the random motions of atoms
Dialogue: 0,0:11:04.00,0:11:06.00,Default,,0000,0000,0000,,making you an apple orchard
Dialogue: 0,0:11:06.00,0:11:08.00,Default,,0000,0000,0000,,and some sugar and an oven,
Dialogue: 0,0:11:08.00,0:11:10.00,Default,,0000,0000,0000,,and then making you an apple pie.
Dialogue: 0,0:11:10.00,0:11:13.00,Default,,0000,0000,0000,,So this scenario makes predictions.
Dialogue: 0,0:11:13.00,0:11:15.00,Default,,0000,0000,0000,,And the predictions are
Dialogue: 0,0:11:15.00,0:11:18.00,Default,,0000,0000,0000,,that the fluctuations that make us are minimal.
Dialogue: 0,0:11:18.00,0:11:21.00,Default,,0000,0000,0000,,Even if you imagine that this room we are in now
Dialogue: 0,0:11:21.00,0:11:23.00,Default,,0000,0000,0000,,exists and is real and here we are,
Dialogue: 0,0:11:23.00,0:11:25.00,Default,,0000,0000,0000,,and we have, not only our memories,
Dialogue: 0,0:11:25.00,0:11:27.00,Default,,0000,0000,0000,,but our impression that outside there's something
Dialogue: 0,0:11:27.00,0:11:31.00,Default,,0000,0000,0000,,called Caltech and the United States and the Milky Way Galaxy,
Dialogue: 0,0:11:31.00,0:11:34.00,Default,,0000,0000,0000,,it's much easier for all those impressions to randomly fluctuate into your brain
Dialogue: 0,0:11:34.00,0:11:36.00,Default,,0000,0000,0000,,than for them actually to randomly fluctuate
Dialogue: 0,0:11:36.00,0:11:39.00,Default,,0000,0000,0000,,into Caltech, the United States and the galaxy.
Dialogue: 0,0:11:39.00,0:11:41.00,Default,,0000,0000,0000,,The good news is that,
Dialogue: 0,0:11:41.00,0:11:44.00,Default,,0000,0000,0000,,therefore, this scenario does not work; it is not right.
Dialogue: 0,0:11:44.00,0:11:47.00,Default,,0000,0000,0000,,This scenario predicts that we should be a minimal fluctuation.
Dialogue: 0,0:11:47.00,0:11:49.00,Default,,0000,0000,0000,,Even if you left our galaxy out,
Dialogue: 0,0:11:49.00,0:11:51.00,Default,,0000,0000,0000,,you would not get a hundred billion other galaxies.
Dialogue: 0,0:11:51.00,0:11:53.00,Default,,0000,0000,0000,,And Feynman also understood this.
Dialogue: 0,0:11:53.00,0:11:57.00,Default,,0000,0000,0000,,Feynman says, "From the hypothesis that the world is a fluctuation,
Dialogue: 0,0:11:57.00,0:11:59.00,Default,,0000,0000,0000,,all the predictions are that
Dialogue: 0,0:11:59.00,0:12:01.00,Default,,0000,0000,0000,,if we look at a part of the world we've never seen before,
Dialogue: 0,0:12:01.00,0:12:03.00,Default,,0000,0000,0000,,we will find it mixed up, and not like the piece we've just looked at --
Dialogue: 0,0:12:03.00,0:12:05.00,Default,,0000,0000,0000,,high entropy.
Dialogue: 0,0:12:05.00,0:12:07.00,Default,,0000,0000,0000,,If our order were due to a fluctuation,
Dialogue: 0,0:12:07.00,0:12:09.00,Default,,0000,0000,0000,,we would not expect order anywhere but where we have just noticed it.
Dialogue: 0,0:12:09.00,0:12:13.00,Default,,0000,0000,0000,,We therefore conclude the universe is not a fluctuation."
Dialogue: 0,0:12:13.00,0:12:16.00,Default,,0000,0000,0000,,So that's good. The question is then what is the right answer?
Dialogue: 0,0:12:16.00,0:12:18.00,Default,,0000,0000,0000,,If the universe is not a fluctuation,
Dialogue: 0,0:12:18.00,0:12:21.00,Default,,0000,0000,0000,,why did the early universe have a low entropy?
Dialogue: 0,0:12:21.00,0:12:24.00,Default,,0000,0000,0000,,And I would love to tell you the answer, but I'm running out of time.
Dialogue: 0,0:12:24.00,0:12:26.00,Default,,0000,0000,0000,,(Laughter)
Dialogue: 0,0:12:26.00,0:12:28.00,Default,,0000,0000,0000,,Here is the universe that we tell you about,
Dialogue: 0,0:12:28.00,0:12:30.00,Default,,0000,0000,0000,,versus the universe that really exists.
Dialogue: 0,0:12:30.00,0:12:32.00,Default,,0000,0000,0000,,I just showed you this picture.
Dialogue: 0,0:12:32.00,0:12:34.00,Default,,0000,0000,0000,,The universe is expanding for the last 10 billion years or so.
Dialogue: 0,0:12:34.00,0:12:36.00,Default,,0000,0000,0000,,It's cooling off.
Dialogue: 0,0:12:36.00,0:12:38.00,Default,,0000,0000,0000,,But we now know enough about the future of the universe
Dialogue: 0,0:12:38.00,0:12:40.00,Default,,0000,0000,0000,,to say a lot more.
Dialogue: 0,0:12:40.00,0:12:42.00,Default,,0000,0000,0000,,If the dark energy remains around,
Dialogue: 0,0:12:42.00,0:12:45.00,Default,,0000,0000,0000,,the stars around us will use up their nuclear fuel, they will stop burning.
Dialogue: 0,0:12:45.00,0:12:47.00,Default,,0000,0000,0000,,They will fall into black holes.
Dialogue: 0,0:12:47.00,0:12:49.00,Default,,0000,0000,0000,,We will live in a universe
Dialogue: 0,0:12:49.00,0:12:51.00,Default,,0000,0000,0000,,with nothing in it but black holes.
Dialogue: 0,0:12:51.00,0:12:55.00,Default,,0000,0000,0000,,That universe will last 10 to the 100 years --
Dialogue: 0,0:12:55.00,0:12:57.00,Default,,0000,0000,0000,,a lot longer than our little universe has lived.
Dialogue: 0,0:12:57.00,0:12:59.00,Default,,0000,0000,0000,,The future is much longer than the past.
Dialogue: 0,0:12:59.00,0:13:01.00,Default,,0000,0000,0000,,But even black holes don't last forever.
Dialogue: 0,0:13:01.00,0:13:03.00,Default,,0000,0000,0000,,They will evaporate,
Dialogue: 0,0:13:03.00,0:13:05.00,Default,,0000,0000,0000,,and we will be left with nothing but empty space.
Dialogue: 0,0:13:05.00,0:13:09.00,Default,,0000,0000,0000,,That empty space lasts essentially forever.
Dialogue: 0,0:13:09.00,0:13:12.00,Default,,0000,0000,0000,,However, you notice, since empty space gives off radiation,
Dialogue: 0,0:13:12.00,0:13:14.00,Default,,0000,0000,0000,,there's actually thermal fluctuations,
Dialogue: 0,0:13:14.00,0:13:16.00,Default,,0000,0000,0000,,and it cycles around
Dialogue: 0,0:13:16.00,0:13:18.00,Default,,0000,0000,0000,,all the different possible combinations
Dialogue: 0,0:13:18.00,0:13:21.00,Default,,0000,0000,0000,,of the degrees of freedom that exist in empty space.
Dialogue: 0,0:13:21.00,0:13:23.00,Default,,0000,0000,0000,,So even though the universe lasts forever,
Dialogue: 0,0:13:23.00,0:13:25.00,Default,,0000,0000,0000,,there's only a finite number of things
Dialogue: 0,0:13:25.00,0:13:27.00,Default,,0000,0000,0000,,that can possibly happen in the universe.
Dialogue: 0,0:13:27.00,0:13:29.00,Default,,0000,0000,0000,,They all happen over a period of time
Dialogue: 0,0:13:29.00,0:13:32.00,Default,,0000,0000,0000,,equal to 10 to the 10 to the 120 years.
Dialogue: 0,0:13:32.00,0:13:34.00,Default,,0000,0000,0000,,So here's two questions for you.
Dialogue: 0,0:13:34.00,0:13:37.00,Default,,0000,0000,0000,,Number one: If the universe lasts for 10 to the 10 to the 120 years,
Dialogue: 0,0:13:37.00,0:13:39.00,Default,,0000,0000,0000,,why are we born
Dialogue: 0,0:13:39.00,0:13:42.00,Default,,0000,0000,0000,,in the first 14 billion years of it,
Dialogue: 0,0:13:42.00,0:13:45.00,Default,,0000,0000,0000,,in the warm, comfortable afterglow of the Big Bang?
Dialogue: 0,0:13:45.00,0:13:47.00,Default,,0000,0000,0000,,Why aren't we in empty space?
Dialogue: 0,0:13:47.00,0:13:49.00,Default,,0000,0000,0000,,You might say, "Well there's nothing there to be living,"
Dialogue: 0,0:13:49.00,0:13:51.00,Default,,0000,0000,0000,,but that's not right.
Dialogue: 0,0:13:51.00,0:13:53.00,Default,,0000,0000,0000,,You could be a random fluctuation out of the nothingness.
Dialogue: 0,0:13:53.00,0:13:55.00,Default,,0000,0000,0000,,Why aren't you?
Dialogue: 0,0:13:55.00,0:13:58.00,Default,,0000,0000,0000,,More homework assignment for you.
Dialogue: 0,0:13:58.00,0:14:00.00,Default,,0000,0000,0000,,So like I said, I don't actually know the answer.
Dialogue: 0,0:14:00.00,0:14:02.00,Default,,0000,0000,0000,,I'm going to give you my favorite scenario.
Dialogue: 0,0:14:02.00,0:14:05.00,Default,,0000,0000,0000,,Either it's just like that. There is no explanation.
Dialogue: 0,0:14:05.00,0:14:07.00,Default,,0000,0000,0000,,This is a brute fact about the universe
Dialogue: 0,0:14:07.00,0:14:10.00,Default,,0000,0000,0000,,that you should learn to accept and stop asking questions.
Dialogue: 0,0:14:11.00,0:14:13.00,Default,,0000,0000,0000,,Or maybe the Big Bang
Dialogue: 0,0:14:13.00,0:14:15.00,Default,,0000,0000,0000,,is not the beginning of the universe.
Dialogue: 0,0:14:15.00,0:14:18.00,Default,,0000,0000,0000,,An egg, an unbroken egg, is a low entropy configuration,
Dialogue: 0,0:14:18.00,0:14:20.00,Default,,0000,0000,0000,,and yet, when we open our refrigerator,
Dialogue: 0,0:14:20.00,0:14:22.00,Default,,0000,0000,0000,,we do not go, "Hah, how surprising to find
Dialogue: 0,0:14:22.00,0:14:24.00,Default,,0000,0000,0000,,this low entropy configuration in our refrigerator."
Dialogue: 0,0:14:24.00,0:14:27.00,Default,,0000,0000,0000,,That's because an egg is not a closed system;
Dialogue: 0,0:14:27.00,0:14:29.00,Default,,0000,0000,0000,,it comes out of a chicken.
Dialogue: 0,0:14:29.00,0:14:33.00,Default,,0000,0000,0000,,Maybe the universe comes out of a universal chicken.
Dialogue: 0,0:14:33.00,0:14:35.00,Default,,0000,0000,0000,,Maybe there is something that naturally,
Dialogue: 0,0:14:35.00,0:14:38.00,Default,,0000,0000,0000,,through the growth of the laws of physics,
Dialogue: 0,0:14:38.00,0:14:40.00,Default,,0000,0000,0000,,gives rise to universe like ours
Dialogue: 0,0:14:40.00,0:14:42.00,Default,,0000,0000,0000,,in low entropy configurations.
Dialogue: 0,0:14:42.00,0:14:44.00,Default,,0000,0000,0000,,If that's true, it would happen more than once;
Dialogue: 0,0:14:44.00,0:14:47.00,Default,,0000,0000,0000,,we would be part of a much bigger multiverse.
Dialogue: 0,0:14:47.00,0:14:49.00,Default,,0000,0000,0000,,That's my favorite scenario.
Dialogue: 0,0:14:49.00,0:14:52.00,Default,,0000,0000,0000,,So the organizers asked me to end with a bold speculation.
Dialogue: 0,0:14:52.00,0:14:54.00,Default,,0000,0000,0000,,My bold speculation
Dialogue: 0,0:14:54.00,0:14:57.00,Default,,0000,0000,0000,,is that I will be absolutely vindicated by history.
Dialogue: 0,0:14:57.00,0:14:59.00,Default,,0000,0000,0000,,And 50 years from now,
Dialogue: 0,0:14:59.00,0:15:02.00,Default,,0000,0000,0000,,all of my current wild ideas will be accepted as truths
Dialogue: 0,0:15:02.00,0:15:05.00,Default,,0000,0000,0000,,by the scientific and external communities.
Dialogue: 0,0:15:05.00,0:15:07.00,Default,,0000,0000,0000,,We will all believe that our little universe
Dialogue: 0,0:15:07.00,0:15:10.00,Default,,0000,0000,0000,,is just a small part of a much larger multiverse.
Dialogue: 0,0:15:10.00,0:15:13.00,Default,,0000,0000,0000,,And even better, we will understand what happened at the Big Bang
Dialogue: 0,0:15:13.00,0:15:15.00,Default,,0000,0000,0000,,in terms of a theory
Dialogue: 0,0:15:15.00,0:15:17.00,Default,,0000,0000,0000,,that we will be able to compare to observations.
Dialogue: 0,0:15:17.00,0:15:19.00,Default,,0000,0000,0000,,This is a prediction. I might be wrong.
Dialogue: 0,0:15:19.00,0:15:21.00,Default,,0000,0000,0000,,But we've been thinking as a human race
Dialogue: 0,0:15:21.00,0:15:23.00,Default,,0000,0000,0000,,about what the universe was like,
Dialogue: 0,0:15:23.00,0:15:26.00,Default,,0000,0000,0000,,why it came to be in the way it did for many, many years.
Dialogue: 0,0:15:26.00,0:15:29.00,Default,,0000,0000,0000,,It's exciting to think we may finally know the answer someday.
Dialogue: 0,0:15:29.00,0:15:31.00,Default,,0000,0000,0000,,Thank you.
Dialogue: 0,0:15:31.00,0:15:33.00,Default,,0000,0000,0000,,(Applause)