<p begin="00:00:00.00" end="00:00:09.73" style="1"> </p>
<p begin="00:00:09.73" end="00:00:12.19" style="1">JOHN MATHER: Well, thank you for coming to hear this story.</p>
<p begin="00:00:12.19" end="00:00:14.43" style="1">I want to tell you about the history of the universe</p>
<p begin="00:00:14.43" end="00:00:15.68" style="1">from the beginning to the end. </p>
<p begin="00:00:15.68" end="00:00:18.10" style="1"> </p>
<p begin="00:00:18.10" end="00:00:19.56" style="1">I'm going to leave out a few parts.</p>
<p begin="00:00:19.56" end="00:00:22.22" style="1"> </p>
<p begin="00:00:22.22" end="00:00:24.72" style="1">Everybody's probably heard a lot about the Big Bang theory.</p>
<p begin="00:00:24.72" end="00:00:26.39" style="1">And I just would like to start by saying</p>
<p begin="00:00:26.39" end="00:00:28.37" style="1">that's a really rotten name. </p>
<p begin="00:00:28.37" end="00:00:31.20" style="1">The Big Bang is not nearly an adequate name for something</p>
<p begin="00:00:31.20" end="00:00:33.77" style="1">that's infinite, that's expanding,</p>
<p begin="00:00:33.77" end="00:00:36.08" style="1">has been expanding since the earliest moments we could</p>
<p begin="00:00:36.08" end="00:00:39.74" style="1">imagine, and may continue to expand infinitely</p>
<p begin="00:00:39.74" end="00:00:40.99" style="1">into the future. </p>
<p begin="00:00:40.99" end="00:00:44.32" style="1">So it's definitely not like what people feel and think</p>
<p begin="00:00:44.32" end="00:00:46.20" style="1">of when you say the word Big Bang.</p>
<p begin="00:00:46.20" end="00:00:48.49" style="1">It's not a little firecracker going off over there</p>
<p begin="00:00:48.49" end="00:00:50.13" style="1">at a place and a time. </p>
<p begin="00:00:50.13" end="00:00:53.55" style="1">The entire universe is infinite and it's expanding.</p>
<p begin="00:00:53.55" end="00:00:54.84" style="1">So how did we find this out? </p>
<p begin="00:00:54.84" end="00:00:58.01" style="1">Well, back in 1905, Einstein said</p>
<p begin="00:00:58.01" end="00:00:59.59" style="1">space and time are mixed together.</p>
<p begin="00:00:59.59" end="00:01:01.02" style="1">They're not absolute. </p>
<p begin="00:01:01.02" end="00:01:05.61" style="1">In 1916, he said they are curved by the action of gravitation.</p>
<p begin="00:01:05.61" end="00:01:10.39" style="1">And in 1922, Alexander Freedman said, you know what that means?</p>
<p begin="00:01:10.39" end="00:01:13.95" style="1">The universe is expanding. </p>
<p begin="00:01:13.95" end="00:01:15.60" style="1">George Lemaitre said the same thing.</p>
<p begin="00:01:15.60" end="00:01:19.41" style="1">Einstein said, everybody knows that's wrong.</p>
<p begin="00:01:19.41" end="00:01:23.65" style="1">And your mathematics is correct but your physics is abominable.</p>
<p begin="00:01:23.65" end="00:01:26.21" style="1">So two years after that, Edwin Hubble</p>
<p begin="00:01:26.21" end="00:01:30.12" style="1">drew a chart that showed that distant galaxies are going away</p>
<p begin="00:01:30.12" end="00:01:33.00" style="1">from us at a speed proportional to distance.</p>
<p begin="00:01:33.00" end="00:01:34.28" style="1">1929. </p>
<p begin="00:01:34.28" end="00:01:36.53" style="1">The same year that we discovered the worldwide economy</p>
<p begin="00:01:36.53" end="00:01:39.73" style="1">could collapse, we discovered the entire universe</p>
<p begin="00:01:39.73" end="00:01:41.89" style="1">could expand. </p>
<p begin="00:01:41.89" end="00:01:46.20" style="1">So this leads, then, to a challenge of imagination--</p>
<p begin="00:01:46.20" end="00:01:48.61" style="1">what happened before all that? </p>
<p begin="00:01:48.61" end="00:01:50.74" style="1">So these days, we've had a long time</p>
<p begin="00:01:50.74" end="00:01:52.79" style="1">to think about it since 1929. </p>
<p begin="00:01:52.79" end="00:01:54.58" style="1">And we have some additional worries.</p>
<p begin="00:01:54.58" end="00:01:57.32" style="1">We've learned about quantum mechanics.</p>
<p begin="00:01:57.32" end="00:01:59.53" style="1">And we imagine that gravitation ought</p>
<p begin="00:01:59.53" end="00:02:01.28" style="1">to have quantum mechanics too, although we</p>
<p begin="00:02:01.28" end="00:02:02.83" style="1">don't know how to do that. </p>
<p begin="00:02:02.83" end="00:02:07.01" style="1">So we have an idea that there's an early substrate of some sort</p>
<p begin="00:02:07.01" end="00:02:09.98" style="1">that we can't understand, may never understand,</p>
<p begin="00:02:09.98" end="00:02:12.06" style="1">but it has some kind of properties</p>
<p begin="00:02:12.06" end="00:02:15.68" style="1">that allow the universe to do something we now believe called</p>
<p begin="00:02:15.68" end="00:02:19.91" style="1">cosmic inflation, where it's named after the inflation</p>
<p begin="00:02:19.91" end="00:02:22.27" style="1">that we have from economics again,</p>
<p begin="00:02:22.27" end="00:02:25.36" style="1">an exponential acceleration, rapid growth that</p>
<p begin="00:02:25.36" end="00:02:27.44" style="1">sets off an early expanding universe</p>
<p begin="00:02:27.44" end="00:02:31.41" style="1">and fills it up with particles and with Higgs fields,</p>
<p begin="00:02:31.41" end="00:02:33.61" style="1">the very same Higgs field that is represented</p>
<p begin="00:02:33.61" end="00:02:38.03" style="1">by the Bosons they just found at CERN a few months ago.</p>
<p begin="00:02:38.03" end="00:02:40.75" style="1">So that, then, according to our imagination,</p>
<p begin="00:02:40.75" end="00:02:44.02" style="1">leads off to the stuff that we see today-- the galaxies,</p>
<p begin="00:02:44.02" end="00:02:46.97" style="1">the gaseous material, the dark matter that astronomers can</p>
<p begin="00:02:46.97" end="00:02:50.93" style="1">detect but cannot see, the cosmic microwave background</p>
<p begin="00:02:50.93" end="00:02:53.48" style="1">radiation which is the heat that's left over from the early</p>
<p begin="00:02:53.48" end="00:02:56.05" style="1">universe, and the dark energy that we also can measure</p>
<p begin="00:02:56.05" end="00:02:57.36" style="1">but cannot see. </p>
<p begin="00:02:57.36" end="00:02:59.15" style="1">So by the way, we shouldn't be calling them</p>
<p begin="00:02:59.15" end="00:03:00.34" style="1">dark matter and energy. </p>
<p begin="00:03:00.34" end="00:03:02.34" style="1">We should be calling them transparent</p>
<p begin="00:03:02.34" end="00:03:04.49" style="1">because you can't see them at all.</p>
<p begin="00:03:04.49" end="00:03:07.96" style="1">Now I've got a beautiful but illegal picture to show you.</p>
<p begin="00:03:07.96" end="00:03:10.22" style="1">This picture is illegal because it</p>
<p begin="00:03:10.22" end="00:03:12.38" style="1">presents the universe from outside.</p>
<p begin="00:03:12.38" end="00:03:15.92" style="1"> </p>
<p begin="00:03:15.92" end="00:03:17.84" style="1">But it captures the sequence of events</p>
<p begin="00:03:17.84" end="00:03:19.70" style="1">that I wanted to tell you about. </p>
<p begin="00:03:19.70" end="00:03:23.34" style="1">We have this idea on the left of the quantum fluctuations</p>
<p begin="00:03:23.34" end="00:03:26.40" style="1">and the inflation that's often expansion.</p>
<p begin="00:03:26.40" end="00:03:29.38" style="1">And we are purely imaginary about what</p>
<p begin="00:03:29.38" end="00:03:31.44" style="1">was there before that. </p>
<p begin="00:03:31.44" end="00:03:35.20" style="1">We calculate that after about 400,000 years of expansion,</p>
<p begin="00:03:35.20" end="00:03:36.87" style="1">the universe would cool off to the point</p>
<p begin="00:03:36.87" end="00:03:38.60" style="1">where it become transparent. </p>
<p begin="00:03:38.60" end="00:03:41.11" style="1">So the heat radiation that existed in those earliest</p>
<p begin="00:03:41.11" end="00:03:44.29" style="1">moments would then become free to move through the universe</p>
<p begin="00:03:44.29" end="00:03:46.16" style="1">and come to our detectors. </p>
<p begin="00:03:46.16" end="00:03:49.54" style="1">Then after that, we imagine it took another 400 billion years</p>
<p begin="00:03:49.54" end="00:03:52.74" style="1">roughly before the first stars and galaxies could form.</p>
<p begin="00:03:52.74" end="00:03:55.88" style="1">And I'll show you a movie later about how that might happen.</p>
<p begin="00:03:55.88" end="00:03:58.46" style="1">Then the universe continues to expand.</p>
<p begin="00:03:58.46" end="00:04:00.75" style="1">And finally, on the right-hand side of this picture,</p>
<p begin="00:04:00.75" end="00:04:03.96" style="1">we have an image of the WMAP satellite, the Wilkinson</p>
<p begin="00:04:03.96" end="00:04:07.41" style="1">Microwave Anisotropy Probe, which was the second cosmology</p>
<p begin="00:04:07.41" end="00:04:10.73" style="1">satellite to measure the heat of the background radiation.</p>
<p begin="00:04:10.73" end="00:04:13.28" style="1">So there's the illegal picture. </p>
<p begin="00:04:13.28" end="00:04:15.17" style="1">But please don't worry. </p>
<p begin="00:04:15.17" end="00:04:16.96" style="1">It's the best we can do. </p>
<p begin="00:04:16.96" end="00:04:19.81" style="1">So now I have a movie, which is also maybe not</p>
<p begin="00:04:19.81" end="00:04:20.94" style="1">quite so illegal. </p>
<p begin="00:04:20.94" end="00:04:27.01" style="1">It starts off with a bang, which is, as I say, illegal.</p>
<p begin="00:04:27.01" end="00:04:30.36" style="1">And then it will illustrate the hot and cold spots</p>
<p begin="00:04:30.36" end="00:04:33.47" style="1">in the microwave radiation, which we believe trace back</p>
<p begin="00:04:33.47" end="00:04:35.55" style="1">to those first moments, the quantum mechanical</p>
<p begin="00:04:35.55" end="00:04:39.15" style="1">fluctuations, if there were any, in the early universe.</p>
<p begin="00:04:39.15" end="00:04:42.83" style="1">We say that the universe wasn't completely uniform because</p>
<p begin="00:04:42.83" end="00:04:44.15" style="1">of those spots. </p>
<p begin="00:04:44.15" end="00:04:47.01" style="1">And therefore gravity, acting across tremendous distances</p>
<p begin="00:04:47.01" end="00:04:49.93" style="1">of space, is able to slow down the expansion of certain parts</p>
<p begin="00:04:49.93" end="00:04:51.96" style="1">of the material and have it fall back in.</p>
<p begin="00:04:51.96" end="00:04:55.20" style="1">And so we now have a computer generated simulation,</p>
<p begin="00:04:55.20" end="00:04:59.31" style="1">a movie of the gravity pulling stuff back together.</p>
<p begin="00:04:59.31" end="00:05:02.06" style="1">And by the way, the universe is still</p>
<p begin="00:05:02.06" end="00:05:03.43" style="1">expanding while this has happened</p>
<p begin="00:05:03.43" end="00:05:06.43" style="1">but the movie is zooming out so you don't notice that part.</p>
<p begin="00:05:06.43" end="00:05:08.67" style="1">What we see here is first the dark matter, which</p>
<p begin="00:05:08.67" end="00:05:11.38" style="1">is the bluish stuff, is actually providing</p>
<p begin="00:05:11.38" end="00:05:12.62" style="1">most of the gravitation. </p>
<p begin="00:05:12.62" end="00:05:16.13" style="1">And it's falling into the centers, sort of spontaneously</p>
<p begin="00:05:16.13" end="00:05:19.54" style="1">forming giant structures that look like stringy stuff</p>
<p begin="00:05:19.54" end="00:05:20.67" style="1">through space. </p>
<p begin="00:05:20.67" end="00:05:23.92" style="1">And simultaneously a lot of space is emptying out.</p>
<p begin="00:05:23.92" end="00:05:25.85" style="1">Material is falling in together. </p>
<p begin="00:05:25.85" end="00:05:28.38" style="1">The yellow stuff is ordinary material, ordinary matter</p>
<p begin="00:05:28.38" end="00:05:29.89" style="1">like we're made out of. </p>
<p begin="00:05:29.89" end="00:05:32.27" style="1">And so what we're watching here in this simulation</p>
<p begin="00:05:32.27" end="00:05:36.94" style="1">is a galaxy being formed by stuff falling in.</p>
<p begin="00:05:36.94" end="00:05:39.58" style="1">This is probably true, more or less.</p>
<p begin="00:05:39.58" end="00:05:42.70" style="1">So that's a movie of what might have been our past.</p>
<p begin="00:05:42.70" end="00:05:44.07" style="1">Now can we tell where we're going</p>
<p begin="00:05:44.07" end="00:05:45.73" style="1">to have to do a little work to find out</p>
<p begin="00:05:45.73" end="00:05:47.81" style="1">if that's a true story? </p>
<p begin="00:05:47.81" end="00:05:49.67" style="1">So now a few beautiful pictures. </p>
<p begin="00:05:49.67" end="00:05:53.33" style="1">This is a nebula called the whirlpool nebula.</p>
<p begin="00:05:53.33" end="00:05:57.50" style="1">It was the first spiral galaxy that was known to be a spiral.</p>
<p begin="00:05:57.50" end="00:06:01.45" style="1">Lord Ross in Ireland in 1845 had a pretty big</p>
<p begin="00:06:01.45" end="00:06:02.89" style="1">metallic telescope. </p>
<p begin="00:06:02.89" end="00:06:05.16" style="1">And he was able to see with his eye</p>
<p begin="00:06:05.16" end="00:06:07.39" style="1">that this thing has a spiral structure.</p>
<p begin="00:06:07.39" end="00:06:09.10" style="1">He did not know at that time, of course,</p>
<p begin="00:06:09.10" end="00:06:10.18" style="1">that it was made of stars. </p>
<p begin="00:06:10.18" end="00:06:11.93" style="1">It took another half a century or more</p>
<p begin="00:06:11.93" end="00:06:14.91" style="1">before we knew that there were stars in those things.</p>
<p begin="00:06:14.91" end="00:06:17.16" style="1">But this is an image of something a little bit</p>
<p begin="00:06:17.16" end="00:06:21.14" style="1">like the galaxy the Milky Way that we live in today.</p>
<p begin="00:06:21.14" end="00:06:22.51" style="1">And you see it face on. </p>
<p begin="00:06:22.51" end="00:06:23.99" style="1">If you were able to see it edge on,</p>
<p begin="00:06:23.99" end="00:06:26.20" style="1">it would have roughly the proportions of a phonograph</p>
<p begin="00:06:26.20" end="00:06:29.70" style="1">record-- extremely thin, maybe a little warped,</p>
<p begin="00:06:29.70" end="00:06:31.98" style="1">stars orbiting around the center.</p>
<p begin="00:06:31.98" end="00:06:35.88" style="1">There are dark areas that are actually caused by dust clouds</p>
<p begin="00:06:35.88" end="00:06:38.20" style="1">in space that are absorbing the starlight there.</p>
<p begin="00:06:38.20" end="00:06:41.70" style="1">And there are red areas which are glowing gas.</p>
<p begin="00:06:41.70" end="00:06:43.99" style="1">And there's even a little satellite galaxy,</p>
<p begin="00:06:43.99" end="00:06:47.89" style="1">a neighboring galaxy over here, which is influencing this one.</p>
<p begin="00:06:47.89" end="00:06:49.51" style="1">I guess the presumption is that they're</p>
<p begin="00:06:49.51" end="00:06:51.97" style="1">interacting pretty strongly with each other.</p>
<p begin="00:06:51.97" end="00:06:55.60" style="1">So this is one of the things we have to understand and compare</p>
<p begin="00:06:55.60" end="00:06:57.42" style="1">with the movie that I just showed you.</p>
<p begin="00:06:57.42" end="00:07:00.93" style="1">See if the movie comes out like this.</p>
<p begin="00:07:00.93" end="00:07:02.10" style="1">Another picture to show you. </p>
<p begin="00:07:02.10" end="00:07:04.68" style="1">This is a piece of the Orion Nebula.</p>
<p begin="00:07:04.68" end="00:07:07.65" style="1">The Orion Nebula is the center star,</p>
<p begin="00:07:07.65" end="00:07:10.47" style="1">as your eye sees it, in the sword of Orion.</p>
<p begin="00:07:10.47" end="00:07:14.52" style="1">And it's a place where stars are being born today.</p>
<p begin="00:07:14.52" end="00:07:16.61" style="1">There are several thousand stars in there,</p>
<p begin="00:07:16.61" end="00:07:19.13" style="1">including some that are too little even to quite burn.</p>
<p begin="00:07:19.13" end="00:07:21.35" style="1">They're called brown dwarf stars.</p>
<p begin="00:07:21.35" end="00:07:23.73" style="1">So anyway, this is a place to study more.</p>
<p begin="00:07:23.73" end="00:07:26.20" style="1">Because this is a place where stars like the sun</p>
<p begin="00:07:26.20" end="00:07:29.03" style="1">are being born or have recently been born.</p>
<p begin="00:07:29.03" end="00:07:33.20" style="1">So it's beautiful to look at and it enchants the imagination.</p>
<p begin="00:07:33.20" end="00:07:34.98" style="1">So now another beautiful picture.</p>
<p begin="00:07:34.98" end="00:07:38.14" style="1">This is a place where a star has exploded.</p>
<p begin="00:07:38.14" end="00:07:41.48" style="1">This is a combined x-ray and visible light picture</p>
<p begin="00:07:41.48" end="00:07:42.93" style="1">of the Crab Nebula. </p>
<p begin="00:07:42.93" end="00:07:47.02" style="1">Crab Nebula is the first nebula in Messier's catalog.</p>
<p begin="00:07:47.02" end="00:07:48.85" style="1">And it turns out to be an exploded star.</p>
<p begin="00:07:48.85" end="00:07:52.68" style="1">It blew up in 1054 AD and it was observed by Chinese astronomers</p>
<p begin="00:07:52.68" end="00:07:55.28" style="1">to be visible-- very, very bright.</p>
<p begin="00:07:55.28" end="00:07:57.21" style="1">I think they could see it in the daytime.</p>
<p begin="00:07:57.21" end="00:07:59.09" style="1">Anyway, this is also an important part</p>
<p begin="00:07:59.09" end="00:08:01.71" style="1">of our kind of history, because the chemical elements</p>
<p begin="00:08:01.71" end="00:08:05.55" style="1">that we're made of-- carbon, oxygen, nitrogen, sulfur, iron,</p>
<p begin="00:08:05.55" end="00:08:08.36" style="1">calcium, that we're seeing in here in our room,</p>
<p begin="00:08:08.36" end="00:08:10.84" style="1">they were produced in these kinds of explosions.</p>
<p begin="00:08:10.84" end="00:08:12.76" style="1">And then the material went back out into space</p>
<p begin="00:08:12.76" end="00:08:15.68" style="1">and was recycled. </p>
<p begin="00:08:15.68" end="00:08:17.10" style="1">Not only did it go out into space,</p>
<p begin="00:08:17.10" end="00:08:19.34" style="1">it may have even gone all the way out of our galaxy</p>
<p begin="00:08:19.34" end="00:08:23.51" style="1">and fallen back in to eventually make us.</p>
<p begin="00:08:23.51" end="00:08:25.67" style="1">Now, I'd like to illustrate, and I will show you</p>
<p begin="00:08:25.67" end="00:08:28.37" style="1">that the universe is not stable--</p>
<p begin="00:08:28.37" end="00:08:30.44" style="1">that everything is unstable if you</p>
<p begin="00:08:30.44" end="00:08:32.52" style="1">wait a little while or a long time.</p>
<p begin="00:08:32.52" end="00:08:36.35" style="1">And it's particularly unstable because gravitation</p>
<p begin="00:08:36.35" end="00:08:38.80" style="1">reaches across infinite space and pulls stuff</p>
<p begin="00:08:38.80" end="00:08:40.60" style="1">together and liberates energy. </p>
<p begin="00:08:40.60" end="00:08:43.87" style="1">So there is an almost a unlimited amount</p>
<p begin="00:08:43.87" end="00:08:46.56" style="1">of energy available to support complexity.</p>
<p begin="00:08:46.56" end="00:08:49.89" style="1">So because of that, we have this amazing sequence of events.</p>
<p begin="00:08:49.89" end="00:08:52.52" style="1">The gas clouds form the stars and galaxies,</p>
<p begin="00:08:52.52" end="00:08:54.53" style="1">the stars blow up to make supernovae,</p>
<p begin="00:08:54.53" end="00:08:56.35" style="1">which liberate the chemical elements.</p>
<p begin="00:08:56.35" end="00:08:58.98" style="1">They go out and get recycled and recycled.</p>
<p begin="00:08:58.98" end="00:09:01.09" style="1">And then we make new stars and planets.</p>
<p begin="00:09:01.09" end="00:09:04.13" style="1">And so here we are in our own solar system,</p>
<p begin="00:09:04.13" end="00:09:07.28" style="1">the result of chaotic instability.</p>
<p begin="00:09:07.28" end="00:09:11.67" style="1">So Mr. Blake, it's unstable and mysterious.</p>
<p begin="00:09:11.67" end="00:09:13.82" style="1">Then here on Earth everything's unstable as well.</p>
<p begin="00:09:13.82" end="00:09:16.21" style="1">The geological instability took a collection</p>
<p begin="00:09:16.21" end="00:09:19.28" style="1">of more or less random things falling together and separated</p>
<p begin="00:09:19.28" end="00:09:22.60" style="1">the Earth into layers, with iron in the middle, rocks floating</p>
<p begin="00:09:22.60" end="00:09:24.50" style="1">on the surface, continents moving around,</p>
<p begin="00:09:24.50" end="00:09:26.41" style="1">floating-- they're doing amazing things.</p>
<p begin="00:09:26.41" end="00:09:28.34" style="1">Unstable atmospheres. </p>
<p begin="00:09:28.34" end="00:09:30.85" style="1">A tremendous number of unstable micro-environments</p>
<p begin="00:09:30.85" end="00:09:33.56" style="1">which we're able to somehow produce ourselves,</p>
<p begin="00:09:33.56" end="00:09:36.01" style="1">produce life through chemical fractionation</p>
<p begin="00:09:36.01" end="00:09:37.55" style="1">and who knows what. </p>
<p begin="00:09:37.55" end="00:09:40.76" style="1">So all of this is possible because of the heat of the sun,</p>
<p begin="00:09:40.76" end="00:09:42.08" style="1">keeps this ongoing. </p>
<p begin="00:09:42.08" end="00:09:44.75" style="1">It is possible for nature to produce little heat engines</p>
<p begin="00:09:44.75" end="00:09:46.06" style="1">all by itself. </p>
<p begin="00:09:46.06" end="00:09:49.40" style="1">And eventually, therefore, to support evolution-- people,</p>
<p begin="00:09:49.40" end="00:09:52.42" style="1">cultural evolution, and our own future,</p>
<p begin="00:09:52.42" end="00:09:56.95" style="1">if we wish to travel through the solar system and to the stars</p>
<p begin="00:09:56.95" end="00:09:59.51" style="1">if the robot's want to go. </p>
<p begin="00:09:59.51" end="00:10:02.04" style="1">So now I have a movie to illustrate the instability</p>
<p begin="00:10:02.04" end="00:10:03.19" style="1">that I mentioned. </p>
<p begin="00:10:03.19" end="00:10:06.67" style="1">This is a simulation of the early solar system.</p>
<p begin="00:10:06.67" end="00:10:08.96" style="1">It has four giant planets-- those</p>
<p begin="00:10:08.96" end="00:10:10.50" style="1">are the orbits they're showing here--</p>
<p begin="00:10:10.50" end="00:10:12.54" style="1">and plus a lot of little green rocks out there.</p>
<p begin="00:10:12.54" end="00:10:14.16" style="1">Those are comets and asteroids that</p>
<p begin="00:10:14.16" end="00:10:16.86" style="1">are left over from the earliest moments.</p>
<p begin="00:10:16.86" end="00:10:19.18" style="1">And in this simulation, the orbits are stable.</p>
<p begin="00:10:19.18" end="00:10:21.59" style="1">And they run along for about 900 million years.</p>
<p begin="00:10:21.59" end="00:10:24.49" style="1">And then kabluey, you will see that just purely</p>
<p begin="00:10:24.49" end="00:10:26.84" style="1">by the action of gravitation acting</p>
<p begin="00:10:26.84" end="00:10:29.06" style="1">on more or less point-like objects,</p>
<p begin="00:10:29.06" end="00:10:31.14" style="1">the system can be unstable. </p>
<p begin="00:10:31.14" end="00:10:33.17" style="1">So this is pretty likely to be true from what</p>
<p begin="00:10:33.17" end="00:10:35.13" style="1">we see in the solar system. </p>
<p begin="00:10:35.13" end="00:10:36.63" style="1">And this is the important part. </p>
<p begin="00:10:36.63" end="00:10:38.05" style="1">Look at them go. </p>
<p begin="00:10:38.05" end="00:10:40.30" style="1">The rocks are thrown everywhere. </p>
<p begin="00:10:40.30" end="00:10:42.22" style="1">Now, that would be a bad time to be alive here</p>
<p begin="00:10:42.22" end="00:10:45.85" style="1">because you would be bombarded by meteors and killer asteroids</p>
<p begin="00:10:45.85" end="00:10:48.48" style="1">all the time. </p>
<p begin="00:10:48.48" end="00:10:50.45" style="1">And it wouldn't be just every few hundred years</p>
<p begin="00:10:50.45" end="00:10:53.44" style="1">that you'd get a meteor strike in Russia.</p>
<p begin="00:10:53.44" end="00:10:55.23" style="1">You'd get them every few days. </p>
<p begin="00:10:55.23" end="00:10:58.66" style="1">So this has cleared out the solar system mostly.</p>
<p begin="00:10:58.66" end="00:11:01.47" style="1">Most of the little rocks are gone-- indeed,</p>
<p begin="00:11:01.47" end="00:11:03.53" style="1">our outer solar system is empty. </p>
<p begin="00:11:03.53" end="00:11:05.91" style="1">And we do not have bombardments. </p>
<p begin="00:11:05.91" end="00:11:08.70" style="1">We have a history of the record of the bombardments</p>
<p begin="00:11:08.70" end="00:11:09.82" style="1">on the surface of the moon. </p>
<p begin="00:11:09.82" end="00:11:11.01" style="1">And we can read it. </p>
<p begin="00:11:11.01" end="00:11:14.73" style="1">So we know that more or less something like this did happen.</p>
<p begin="00:11:14.73" end="00:11:18.90" style="1">So anyway, instability, chaos, and that's</p>
<p begin="00:11:18.90" end="00:11:20.87" style="1">how come we are here. </p>
<p begin="00:11:20.87" end="00:11:22.42" style="1">So now think about the future. </p>
<p begin="00:11:22.42" end="00:11:24.30" style="1">I told you I would tell you about the future.</p>
<p begin="00:11:24.30" end="00:11:27.91" style="1">There's a little bit I can say just by looking at what we see.</p>
<p begin="00:11:27.91" end="00:11:31.72" style="1">Well, if I really could see you wouldn't believe me anyway,</p>
<p begin="00:11:31.72" end="00:11:35.72" style="1">because it's not unusual for the seers in ancient mythology</p>
<p begin="00:11:35.72" end="00:11:37.51" style="1">to be cursed. </p>
<p begin="00:11:37.51" end="00:11:40.44" style="1">In fact, if you commit a sin like refusing Apollo</p>
<p begin="00:11:40.44" end="00:11:43.85" style="1">you will be cursed and never believed.</p>
<p begin="00:11:43.85" end="00:11:45.69" style="1">Anyway, my prediction is very simple.</p>
<p begin="00:11:45.69" end="00:11:47.95" style="1">It'll be like the present, only more so.</p>
<p begin="00:11:47.95" end="00:11:51.72" style="1">More people, more germs, more heat, carbon dioxide,</p>
<p begin="00:11:51.72" end="00:11:55.86" style="1">acid rain, acid oceans, rising seas, and all those things</p>
<p begin="00:11:55.86" end="00:11:57.75" style="1">that we're already observing will probably</p>
<p begin="00:11:57.75" end="00:11:59.25" style="1">continue for awhile. </p>
<p begin="00:11:59.25" end="00:12:01.05" style="1">And we're going to keep on building-- well,</p>
<p begin="00:12:01.05" end="00:12:03.41" style="1">humans was like to build because we like to build it.</p>
<p begin="00:12:03.41" end="00:12:06.28" style="1">And so everything that you can imagine we're doing,</p>
<p begin="00:12:06.28" end="00:12:08.21" style="1">we're going to do it some more. </p>
<p begin="00:12:08.21" end="00:12:10.36" style="1">And so what will happen? </p>
<p begin="00:12:10.36" end="00:12:12.33" style="1">I guess computers are coming. </p>
<p begin="00:12:12.33" end="00:12:15.91" style="1">Artificial intelligence might even becoming pretty quickly.</p>
<p begin="00:12:15.91" end="00:12:18.63" style="1">And Meanwhile, we're giving up our privacy quite rapidly</p>
<p begin="00:12:18.63" end="00:12:19.61" style="1">as well. </p>
<p begin="00:12:19.61" end="00:12:21.82" style="1">You can sort of observe that concentration</p>
<p begin="00:12:21.82" end="00:12:24.51" style="1">of powers, whoever has great powers</p>
<p begin="00:12:24.51" end="00:12:27.57" style="1">has great powers and the ability to gain more powers.</p>
<p begin="00:12:27.57" end="00:12:29.25" style="1">So that's going to be interesting.</p>
<p begin="00:12:29.25" end="00:12:31.56" style="1">And I don't know whether we're really going to like it.</p>
<p begin="00:12:31.56" end="00:12:33.81" style="1">But at any rate, moving on. </p>
<p begin="00:12:33.81" end="00:12:37.35" style="1">There are obvious limitations as well.</p>
<p begin="00:12:37.35" end="00:12:40.56" style="1">We have about a billion years before the sun</p>
<p begin="00:12:40.56" end="00:12:41.98" style="1">gets too hot for us to live here.</p>
<p begin="00:12:41.98" end="00:12:46.52" style="1">A billion years is a long time and compared to 25 years,</p>
<p begin="00:12:46.52" end="00:12:50.63" style="1">that's what, 40 million generations of us</p>
<p begin="00:12:50.63" end="00:12:52.19" style="1">or whatever follows us. </p>
<p begin="00:12:52.19" end="00:12:54.52" style="1">So things are going to run out and change and everything</p>
<p begin="00:12:54.52" end="00:12:56.22" style="1">will be chaotic. </p>
<p begin="00:12:56.22" end="00:12:57.63" style="1">But it'll be interesting. </p>
<p begin="00:12:57.63" end="00:12:59.84" style="1">So it'll be a good time to be a scientist, of course,</p>
<p begin="00:12:59.84" end="00:13:02.05" style="1">because that's what we like to do.</p>
<p begin="00:13:02.05" end="00:13:04.69" style="1">So everything's going to change. </p>
<p begin="00:13:04.69" end="00:13:06.80" style="1">That's about the only thing I can really tell you.</p>
<p begin="00:13:06.80" end="00:13:09.86" style="1">But on the very long term, the sun changes.</p>
<p begin="00:13:09.86" end="00:13:14.22" style="1">So then after that, it turns into a white dwarf.</p>
<p begin="00:13:14.22" end="00:13:15.80" style="1">And maybe we'll need some space travel</p>
<p begin="00:13:15.80" end="00:13:18.77" style="1">to at least get to a different planet.</p>
<p begin="00:13:18.77" end="00:13:20.67" style="1">How far can this all go? </p>
<p begin="00:13:20.67" end="00:13:24.85" style="1">Well, eventually I think robots will be everywhere.</p>
<p begin="00:13:24.85" end="00:13:26.70" style="1">Bob Ballard told me last time I saw him</p>
<p begin="00:13:26.70" end="00:13:29.48" style="1">that they're already running around the bottom of the ocean.</p>
<p begin="00:13:29.48" end="00:13:31.15" style="1">And he uses them on purpose. </p>
<p begin="00:13:31.15" end="00:13:33.56" style="1">Other people are using them for commercial purposes,</p>
<p begin="00:13:33.56" end="00:13:36.43" style="1">because that's where an awful lot of resources are.</p>
<p begin="00:13:36.43" end="00:13:40.58" style="1">And robots can go any place that we can go and a lot more.</p>
<p begin="00:13:40.58" end="00:13:43.04" style="1">And I think the future is clearly</p>
<p begin="00:13:43.04" end="00:13:45.99" style="1">in that area for rapid expansion.</p>
<p begin="00:13:45.99" end="00:13:48.92" style="1">We are just as fragile as we were 100,000 years ago.</p>
<p begin="00:13:48.92" end="00:13:51.36" style="1">And robots are changing. </p>
<p begin="00:13:51.36" end="00:13:54.33" style="1">So we know that if you want to go to Mars,</p>
<p begin="00:13:54.33" end="00:13:57.43" style="1">you might get sick on the way if you take a long time.</p>
<p begin="00:13:57.43" end="00:13:59.99" style="1">In fact, recent measurement just probed how much</p>
<p begin="00:13:59.99" end="00:14:01.81" style="1">radiation damage you would get. </p>
<p begin="00:14:01.81" end="00:14:03.39" style="1">And it's just been reported this week.</p>
<p begin="00:14:03.39" end="00:14:05.18" style="1">So we know what we would have to deal with</p>
<p begin="00:14:05.18" end="00:14:07.85" style="1">to protect our future astronauts going to Mars.</p>
<p begin="00:14:07.85" end="00:14:10.98" style="1">And they might or might not like it.</p>
<p begin="00:14:10.98" end="00:14:13.30" style="1">In the future, I would say robots</p>
<p begin="00:14:13.30" end="00:14:15.44" style="1">can go wherever they want to go. </p>
<p begin="00:14:15.44" end="00:14:17.57" style="1">Or wherever their owners want to send them.</p>
<p begin="00:14:17.57" end="00:14:19.86" style="1">So then you could say, well, how come they're not here.</p>
<p begin="00:14:19.86" end="00:14:21.32" style="1">How come we haven't been discovered</p>
<p begin="00:14:21.32" end="00:14:23.91" style="1">by other people's robots? </p>
<p begin="00:14:23.91" end="00:14:26.83" style="1">And I think the basic answer is space is very, very large.</p>
<p begin="00:14:26.83" end="00:14:28.85" style="1">And we are very, very small. </p>
<p begin="00:14:28.85" end="00:14:31.47" style="1">So even if there are other robotic civilizations</p>
<p begin="00:14:31.47" end="00:14:34.03" style="1">out there, they may not have had time to get here.</p>
<p begin="00:14:34.03" end="00:14:35.36" style="1">And they might never. </p>
<p begin="00:14:35.36" end="00:14:37.44" style="1">So now I want to wrap up by showing you</p>
<p begin="00:14:37.44" end="00:14:40.28" style="1">a movie of something that is in our future.</p>
<p begin="00:14:40.28" end="00:14:42.61" style="1">And we've just measured something about it.</p>
<p begin="00:14:42.61" end="00:14:45.75" style="1">In a couple of billion years, two or three,</p>
<p begin="00:14:45.75" end="00:14:48.90" style="1">our Milky Way is planning to collide with the nearest</p>
<p begin="00:14:48.90" end="00:14:52.86" style="1">large nebula, the Andromeda Nebula, M31.</p>
<p begin="00:14:52.86" end="00:14:55.81" style="1">And this is another giant supercomputer simulation</p>
<p begin="00:14:55.81" end="00:14:57.84" style="1">that shows how this could work. </p>
<p begin="00:14:57.84" end="00:15:01.21" style="1">When galaxies collide, what happens is the stars go right--</p>
<p begin="00:15:01.21" end="00:15:03.63" style="1">they're extremely tiny compared to the space between them,</p>
<p begin="00:15:03.63" end="00:15:05.81" style="1">so they go flying right past. </p>
<p begin="00:15:05.81" end="00:15:07.64" style="1">But they get scrambled up in their orbits.</p>
<p begin="00:15:07.64" end="00:15:10.39" style="1">And so what we're going to see is these two beautiful galaxies</p>
<p begin="00:15:10.39" end="00:15:15.07" style="1">merging together to form something quite different.</p>
<p begin="00:15:15.07" end="00:15:17.48" style="1">In the end, each of them has a black hole in the middle.</p>
<p begin="00:15:17.48" end="00:15:18.98" style="1">The black holes will find themselves</p>
<p begin="00:15:18.98" end="00:15:21.40" style="1">and they will merge and make something quite spectacular</p>
<p begin="00:15:21.40" end="00:15:22.68" style="1">as well. </p>
<p begin="00:15:22.68" end="00:15:26.09" style="1">The solar system is on the outside edge of our Milky Way.</p>
<p begin="00:15:26.09" end="00:15:29.88" style="1">So we don't know whether our fate is to be flung out</p>
<p begin="00:15:29.88" end="00:15:32.15" style="1">or to be captured in. </p>
<p begin="00:15:32.15" end="00:15:33.87" style="1">But it'll be a very spectacular time</p>
<p begin="00:15:33.87" end="00:15:38.66" style="1">to be an astronomer to watch all these stars go flying by.</p>
<p begin="00:15:38.66" end="00:15:43.12" style="1">Well, if I told you correct, if the sun actually wipes us out</p>
<p begin="00:15:43.12" end="00:15:46.37" style="1">in a billion years, we will not be here on this planet.</p>
<p begin="00:15:46.37" end="00:15:49.47" style="1">On the other hand, some future robotic civilization</p>
<p begin="00:15:49.47" end="00:15:50.76" style="1">might be watching. </p>
<p begin="00:15:50.76" end="00:15:55.41" style="1">So it's an extraordinary event that's coming to us.</p>
<p begin="00:15:55.41" end="00:15:59.28" style="1">And maybe this is a good time to stop and say,</p>
<p begin="00:15:59.28" end="00:16:00.67" style="1">what do you think? </p>
<p begin="00:16:00.67" end="00:16:02.62" style="1">Thanks very much. </p>
<p begin="00:16:02.62" end="00:16:09.53" style="1"> </p>