[Script Info] Title: [Events] Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text Dialogue: 0,0:00:00.00,0:00:13.00,Default,,0000,0000,0000,,(Music) Dialogue: 0,0:00:18.00,0:00:20.00,Default,,0000,0000,0000,,Sometimes when I'm on a long plane flight, Dialogue: 0,0:00:20.00,0:00:23.00,Default,,0000,0000,0000,,I gaze out at all those mountains and deserts Dialogue: 0,0:00:23.00,0:00:26.00,Default,,0000,0000,0000,,and try to get my head around how vast our Earth is. Dialogue: 0,0:00:26.00,0:00:29.00,Default,,0000,0000,0000,,And then I remember that there's an object we see every day Dialogue: 0,0:00:29.00,0:00:32.00,Default,,0000,0000,0000,,that would literally fit one million Earths inside it. Dialogue: 0,0:00:32.00,0:00:35.00,Default,,0000,0000,0000,,The sun seems impossibly big Dialogue: 0,0:00:35.00,0:00:38.00,Default,,0000,0000,0000,,but in the great scheme of things, it's a pinprick, Dialogue: 0,0:00:38.00,0:00:43.00,Default,,0000,0000,0000,,one of about 400 billion stars in the Milky Way galaxy, Dialogue: 0,0:00:43.00,0:00:47.00,Default,,0000,0000,0000,,which you can see on a clear night as a pale, white mist stretched across the sky. Dialogue: 0,0:00:47.00,0:00:49.00,Default,,0000,0000,0000,,And it gets worse. Dialogue: 0,0:00:49.00,0:00:53.00,Default,,0000,0000,0000,,There are maybe 100 billion galaxies detectable by our telescopes, Dialogue: 0,0:00:53.00,0:00:58.00,Default,,0000,0000,0000,,so if each star was the size of a single grain of sand, Dialogue: 0,0:00:58.00,0:01:01.00,Default,,0000,0000,0000,,just the Milky Way has enough stars to fill Dialogue: 0,0:01:01.00,0:01:05.00,Default,,0000,0000,0000,,a 30 foot by 30 foot stretch of beach three feet deep with sand. Dialogue: 0,0:01:05.00,0:01:08.00,Default,,0000,0000,0000,,And the entire Earth doesn't have enough beaches Dialogue: 0,0:01:08.00,0:01:11.00,Default,,0000,0000,0000,,to represent the stars in the overall universe. Dialogue: 0,0:01:11.00,0:01:15.00,Default,,0000,0000,0000,,Such a beach would continue for literally hundreds of millions of miles. Dialogue: 0,0:01:15.00,0:01:19.00,Default,,0000,0000,0000,,Holy Stephen Hawking, that is a lot of stars. Dialogue: 0,0:01:19.00,0:01:22.00,Default,,0000,0000,0000,,But he and other physicists now believe in Dialogue: 0,0:01:22.00,0:01:25.00,Default,,0000,0000,0000,,a reality that is unimaginably bigger still. Dialogue: 0,0:01:25.00,0:01:29.00,Default,,0000,0000,0000,,I mean, first of all, the 100 billion galaxies within range of our telescopes Dialogue: 0,0:01:29.00,0:01:32.00,Default,,0000,0000,0000,,are probably a minuscule fraction of the total. Dialogue: 0,0:01:32.00,0:01:35.00,Default,,0000,0000,0000,,Space itself is expanding Dialogue: 0,0:01:35.00,0:01:38.00,Default,,0000,0000,0000,,at an accelerating pace. The vast majority of the galaxies Dialogue: 0,0:01:38.00,0:01:41.00,Default,,0000,0000,0000,,are separating from us so fast Dialogue: 0,0:01:41.00,0:01:43.00,Default,,0000,0000,0000,,that light from them may never reach us. Dialogue: 0,0:01:43.00,0:01:46.00,Default,,0000,0000,0000,,Still, our physical reality here on Earth Dialogue: 0,0:01:46.00,0:01:49.00,Default,,0000,0000,0000,,is intimately connected to those distant, invisible galaxies. Dialogue: 0,0:01:49.00,0:01:52.00,Default,,0000,0000,0000,,We can think of them as part of our universe. Dialogue: 0,0:01:52.00,0:01:55.00,Default,,0000,0000,0000,,They make up a single, giant edifice, Dialogue: 0,0:01:55.00,0:01:58.00,Default,,0000,0000,0000,,obeying the same physical laws and all made from the same types of atoms, electrons, Dialogue: 0,0:01:58.00,0:02:02.00,Default,,0000,0000,0000,,protons, quarks, neutrinos that make up you and me. Dialogue: 0,0:02:02.00,0:02:05.00,Default,,0000,0000,0000,,However, recent theories in physics, Dialogue: 0,0:02:05.00,0:02:07.00,Default,,0000,0000,0000,,including one called string theory, Dialogue: 0,0:02:07.00,0:02:10.00,Default,,0000,0000,0000,,are now telling us there could be countless other universes, Dialogue: 0,0:02:10.00,0:02:12.00,Default,,0000,0000,0000,,built on different types of particles, Dialogue: 0,0:02:12.00,0:02:14.00,Default,,0000,0000,0000,,with different properties, obeying different laws. Dialogue: 0,0:02:14.00,0:02:17.00,Default,,0000,0000,0000,,Most of these universes could never support life, Dialogue: 0,0:02:17.00,0:02:20.00,Default,,0000,0000,0000,,and might flash in and out of existence in a nanosecond, Dialogue: 0,0:02:20.00,0:02:23.00,Default,,0000,0000,0000,,but nonetheless, combined Dialogue: 0,0:02:23.00,0:02:26.00,Default,,0000,0000,0000,,they make up a vast multiverse of possible universes. Dialogue: 0,0:02:26.00,0:02:31.00,Default,,0000,0000,0000,,in up to 11 dimensions, featuring wonders beyond our wildest imagination. Dialogue: 0,0:02:31.00,0:02:33.00,Default,,0000,0000,0000,,And the leading version of string theory Dialogue: 0,0:02:33.00,0:02:36.00,Default,,0000,0000,0000,,predicts a multiverse made of up to 10 to the 500 universes. Dialogue: 0,0:02:36.00,0:02:40.00,Default,,0000,0000,0000,,That's a one followed by 500 zeroes, Dialogue: 0,0:02:40.00,0:02:44.00,Default,,0000,0000,0000,,a number so vast that if every atom in our observable universe Dialogue: 0,0:02:44.00,0:02:46.00,Default,,0000,0000,0000,,had its own universe Dialogue: 0,0:02:46.00,0:02:49.00,Default,,0000,0000,0000,,and all of the atoms in all of those universes Dialogue: 0,0:02:49.00,0:02:51.00,Default,,0000,0000,0000,,each had their own universe, Dialogue: 0,0:02:52.00,0:02:54.00,Default,,0000,0000,0000,,and you repeated that for two more cycles, Dialogue: 0,0:02:54.00,0:02:57.00,Default,,0000,0000,0000,,you'd still be at a tiny fraction of the total -- Dialogue: 0,0:02:57.00,0:03:06.00,Default,,0000,0000,0000,,namely, one trillion trillion trillion trillion trillion trillion trillion trillion trillion trillion trillion trillion trillion trillion trillionth. Dialogue: 0,0:03:06.00,0:03:10.00,Default,,0000,0000,0000,,But even that number is minuscule compared to Dialogue: 0,0:03:10.00,0:03:13.00,Default,,0000,0000,0000,,another number: infinity. Dialogue: 0,0:03:13.00,0:03:16.00,Default,,0000,0000,0000,,Some physicists think the space-time continuum Dialogue: 0,0:03:16.00,0:03:19.00,Default,,0000,0000,0000,,is literally infinite, and that it contains an infinite number of so-called pocket universes Dialogue: 0,0:03:19.00,0:03:22.00,Default,,0000,0000,0000,,with varying properties. Dialogue: 0,0:03:22.00,0:03:24.00,Default,,0000,0000,0000,,How's your brain doing? Dialogue: 0,0:03:24.00,0:03:27.00,Default,,0000,0000,0000,,But quantum theory adds a whole new wrinkle. Dialogue: 0,0:03:27.00,0:03:29.00,Default,,0000,0000,0000,,I mean, the theory's been proven true beyond all doubt, Dialogue: 0,0:03:29.00,0:03:31.00,Default,,0000,0000,0000,,but interpreting it is baffling. Dialogue: 0,0:03:31.00,0:03:34.00,Default,,0000,0000,0000,,And some physicists think you can only un-baffle it Dialogue: 0,0:03:34.00,0:03:37.00,Default,,0000,0000,0000,,if you imagine that huge numbers of parallel universes Dialogue: 0,0:03:37.00,0:03:39.00,Default,,0000,0000,0000,,are being spawned every moment, Dialogue: 0,0:03:39.00,0:03:43.00,Default,,0000,0000,0000,,and many of these universes would actually be very like the world we're in, Dialogue: 0,0:03:43.00,0:03:46.00,Default,,0000,0000,0000,,would include multiple copies of you. Dialogue: 0,0:03:46.00,0:03:50.00,Default,,0000,0000,0000,,In one such universe, you'd graduate with honors and marry the person of your dreams. Dialogue: 0,0:03:50.00,0:03:53.00,Default,,0000,0000,0000,,In another, not so much. Dialogue: 0,0:03:53.00,0:03:55.00,Default,,0000,0000,0000,,There are still some scientists who would say, hogwash. Dialogue: 0,0:03:55.00,0:03:59.00,Default,,0000,0000,0000,,The only meaningful answer to the question of how many universes there are is one, Dialogue: 0,0:03:59.00,0:04:02.00,Default,,0000,0000,0000,,only one universe. Dialogue: 0,0:04:02.00,0:04:05.00,Default,,0000,0000,0000,,And a few philosophers and mystics Dialogue: 0,0:04:05.00,0:04:08.00,Default,,0000,0000,0000,,might argue that even our own universe is an illusion. Dialogue: 0,0:04:08.00,0:04:10.00,Default,,0000,0000,0000,,So, as you can see, Dialogue: 0,0:04:10.00,0:04:13.00,Default,,0000,0000,0000,,right now there is no agreement on this question, Dialogue: 0,0:04:13.00,0:04:14.00,Default,,0000,0000,0000,,not even close. Dialogue: 0,0:04:14.00,0:04:18.00,Default,,0000,0000,0000,,All we know is, the answer is somewhere between zero and infinity. Dialogue: 0,0:04:18.00,0:04:21.00,Default,,0000,0000,0000,,Well, I guess we know one other thing: Dialogue: 0,0:04:21.00,0:04:24.00,Default,,0000,0000,0000,,This is a pretty cool time to be studying physics. Dialogue: 0,0:04:24.00,0:04:27.00,Default,,0000,0000,0000,,We just might be undergoing Dialogue: 0,0:04:27.00,0:04:31.00,Default,,0000,0000,0000,,the biggest paradigm shift in knowledge that humanity has ever seen.