[Script Info] Title: [Events] Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text Dialogue: 0,0:00:01.01,0:00:04.34,Default,,0000,0000,0000,,I'm going to tell you a story\Nfrom 200 years ago. Dialogue: 0,0:00:04.78,0:00:08.04,Default,,0000,0000,0000,,In 1820, French astronomer Alexis Bouvard Dialogue: 0,0:00:08.06,0:00:12.90,Default,,0000,0000,0000,,almost became the second person\Nin human history to discover a planet. Dialogue: 0,0:00:13.33,0:00:16.65,Default,,0000,0000,0000,,He'd been tracking the position\Nof Uranus across the night sky Dialogue: 0,0:00:16.67,0:00:18.41,Default,,0000,0000,0000,,using old star catalogs, Dialogue: 0,0:00:18.43,0:00:20.73,Default,,0000,0000,0000,,and it didn't quite go around the Sun Dialogue: 0,0:00:20.75,0:00:23.17,Default,,0000,0000,0000,,the way that his predictions\Nsaid it should. Dialogue: 0,0:00:23.20,0:00:25.30,Default,,0000,0000,0000,,Sometimes it was a little too fast, Dialogue: 0,0:00:25.32,0:00:27.01,Default,,0000,0000,0000,,sometimes it was a little too slow. Dialogue: 0,0:00:27.03,0:00:30.26,Default,,0000,0000,0000,,Bouvard knew that\Nhis predictions were perfect. Dialogue: 0,0:00:30.78,0:00:34.07,Default,,0000,0000,0000,,So it had to be that those\Nold star catalogs were bad. Dialogue: 0,0:00:34.10,0:00:36.16,Default,,0000,0000,0000,,He told astronomers of the day, Dialogue: 0,0:00:36.18,0:00:37.85,Default,,0000,0000,0000,,"Do better measurements." Dialogue: 0,0:00:38.62,0:00:39.78,Default,,0000,0000,0000,,So they did. Dialogue: 0,0:00:39.80,0:00:42.05,Default,,0000,0000,0000,,Astronomers spent the next two decades Dialogue: 0,0:00:42.07,0:00:46.14,Default,,0000,0000,0000,,meticulously tracking the position\Nof Uranus across the sky, Dialogue: 0,0:00:46.17,0:00:49.84,Default,,0000,0000,0000,,but it still didn't fit\NBouvard's predictions. Dialogue: 0,0:00:49.86,0:00:52.02,Default,,0000,0000,0000,,By 1840, it had become obvious. Dialogue: 0,0:00:52.04,0:00:55.09,Default,,0000,0000,0000,,The problem was not\Nwith those old star catalogs, Dialogue: 0,0:00:55.12,0:00:57.58,Default,,0000,0000,0000,,the problem was with the predictions. Dialogue: 0,0:00:57.100,0:00:59.54,Default,,0000,0000,0000,,And astronomers knew why. Dialogue: 0,0:00:59.56,0:01:03.74,Default,,0000,0000,0000,,They realized that there must be\Na distant, giant planet Dialogue: 0,0:01:03.76,0:01:05.42,Default,,0000,0000,0000,,just beyond the orbit of Uranus Dialogue: 0,0:01:05.44,0:01:07.28,Default,,0000,0000,0000,,that was tugging along at that orbit, Dialogue: 0,0:01:07.30,0:01:09.87,Default,,0000,0000,0000,,sometimes pulling it along a bit too fast, Dialogue: 0,0:01:09.90,0:01:11.56,Default,,0000,0000,0000,,sometimes holding it back. Dialogue: 0,0:01:12.77,0:01:14.78,Default,,0000,0000,0000,,Must have been frustrating back in 1840 Dialogue: 0,0:01:14.80,0:01:18.18,Default,,0000,0000,0000,,to see these gravitational effects\Nof this distant, giant planet Dialogue: 0,0:01:18.20,0:01:21.36,Default,,0000,0000,0000,,but not yet know how to actually find it. Dialogue: 0,0:01:21.100,0:01:24.07,Default,,0000,0000,0000,,Trust me, it's really frustrating. Dialogue: 0,0:01:24.09,0:01:25.55,Default,,0000,0000,0000,,(Laughter) Dialogue: 0,0:01:25.58,0:01:27.83,Default,,0000,0000,0000,,But in 1846, another French astronomer, Dialogue: 0,0:01:27.85,0:01:29.13,Default,,0000,0000,0000,,Urbain Le Verrier, Dialogue: 0,0:01:29.16,0:01:30.33,Default,,0000,0000,0000,,worked through the math Dialogue: 0,0:01:30.35,0:01:33.07,Default,,0000,0000,0000,,and figured out how to predict\Nthe location of the planet. Dialogue: 0,0:01:33.09,0:01:36.19,Default,,0000,0000,0000,,He sent his prediction\Nto the Berlin observatory, Dialogue: 0,0:01:36.22,0:01:37.66,Default,,0000,0000,0000,,they opened up their telescope Dialogue: 0,0:01:37.69,0:01:40.74,Default,,0000,0000,0000,,and in the very first night\Nthey found this faint point of light Dialogue: 0,0:01:40.76,0:01:44.04,Default,,0000,0000,0000,,slowly moving across the sky\Nand discovered Neptune. Dialogue: 0,0:01:44.07,0:01:48.29,Default,,0000,0000,0000,,It was this close on the sky\Nto Le Verrier's predicted location. Dialogue: 0,0:01:49.86,0:01:54.41,Default,,0000,0000,0000,,The story of prediction\Nand discrepancy and new theory Dialogue: 0,0:01:54.43,0:01:57.39,Default,,0000,0000,0000,,and triumphant discoveries is so classic Dialogue: 0,0:01:57.41,0:02:00.40,Default,,0000,0000,0000,,and Le Verrier became so famous from it, Dialogue: 0,0:02:00.43,0:02:03.14,Default,,0000,0000,0000,,that people tried to get in\Non the act right away. Dialogue: 0,0:02:03.16,0:02:05.68,Default,,0000,0000,0000,,In the last 163 years, Dialogue: 0,0:02:05.70,0:02:11.32,Default,,0000,0000,0000,,dozens of astronomers have used\Nsome sort of alleged orbital discrepancy Dialogue: 0,0:02:11.34,0:02:15.50,Default,,0000,0000,0000,,to predict the existence\Nof some new planet in the Solar system. Dialogue: 0,0:02:16.29,0:02:19.01,Default,,0000,0000,0000,,They have always been wrong. Dialogue: 0,0:02:20.14,0:02:22.31,Default,,0000,0000,0000,,The most famous of these\Nerroneous predictions Dialogue: 0,0:02:22.33,0:02:23.77,Default,,0000,0000,0000,,came from Percival Lowell, Dialogue: 0,0:02:23.79,0:02:28.50,Default,,0000,0000,0000,,who was convinced that there must be\Na planet just beyond Uranus and Neptune, Dialogue: 0,0:02:28.53,0:02:30.52,Default,,0000,0000,0000,,messing with those orbits. Dialogue: 0,0:02:30.54,0:02:33.11,Default,,0000,0000,0000,,And so when Pluto was discovered in 1930, Dialogue: 0,0:02:33.13,0:02:34.77,Default,,0000,0000,0000,,at the Lowell Observatory, Dialogue: 0,0:02:34.80,0:02:38.78,Default,,0000,0000,0000,,everybody assumed that it must be\Nthe planet that Lowell had predicted. Dialogue: 0,0:02:39.24,0:02:41.18,Default,,0000,0000,0000,,They were wrong. Dialogue: 0,0:02:41.68,0:02:45.75,Default,,0000,0000,0000,,It turns out, Uranus and Neptune\Nare exactly where they're supposed to be. Dialogue: 0,0:02:45.77,0:02:47.36,Default,,0000,0000,0000,,It took 100 years, Dialogue: 0,0:02:47.39,0:02:49.13,Default,,0000,0000,0000,,but Bouvard was eventually right. Dialogue: 0,0:02:49.16,0:02:52.78,Default,,0000,0000,0000,,Astronomers needed to do\Nbetter measurements. Dialogue: 0,0:02:52.80,0:02:54.58,Default,,0000,0000,0000,,And when they did, Dialogue: 0,0:02:54.60,0:02:57.76,Default,,0000,0000,0000,,those better measurements\Nhad turned out that Dialogue: 0,0:02:57.78,0:03:02.81,Default,,0000,0000,0000,,there is no planet just beyond\Nthe orbit of Uranus and Neptune Dialogue: 0,0:03:02.83,0:03:05.51,Default,,0000,0000,0000,,and Pluto is thousands of times too small Dialogue: 0,0:03:05.53,0:03:08.18,Default,,0000,0000,0000,,to have any effect on those orbits at all. Dialogue: 0,0:03:08.20,0:03:11.86,Default,,0000,0000,0000,,So even though Pluto\Nturned out not to be the planet Dialogue: 0,0:03:11.89,0:03:13.47,Default,,0000,0000,0000,,it was originally thought to be, Dialogue: 0,0:03:13.49,0:03:16.92,Default,,0000,0000,0000,,it was the first discovery\Nof what is now known to be Dialogue: 0,0:03:16.94,0:03:21.70,Default,,0000,0000,0000,,thousands of tiny icy objects\Nin orbit beyond the planets. Dialogue: 0,0:03:21.73,0:03:24.60,Default,,0000,0000,0000,,Here you can see the orbits of Jupiter, Dialogue: 0,0:03:24.62,0:03:27.16,Default,,0000,0000,0000,,Saturn, Uranus and Neptune, Dialogue: 0,0:03:27.19,0:03:30.19,Default,,0000,0000,0000,,and in that little circle\Nin the very center is the Earth Dialogue: 0,0:03:30.21,0:03:33.18,Default,,0000,0000,0000,,and the Sun and almost everything\Nthat you know and love. Dialogue: 0,0:03:33.21,0:03:35.03,Default,,0000,0000,0000,,And those yellow circles at the edge Dialogue: 0,0:03:35.05,0:03:37.79,Default,,0000,0000,0000,,are these icy bodies\Nout beyond the planets. Dialogue: 0,0:03:37.81,0:03:40.11,Default,,0000,0000,0000,,These icy bodies are pushed and pulled Dialogue: 0,0:03:40.13,0:03:42.25,Default,,0000,0000,0000,,by the gravitational fields of the planets Dialogue: 0,0:03:42.27,0:03:44.80,Default,,0000,0000,0000,,in entirely predictable ways. Dialogue: 0,0:03:44.83,0:03:49.55,Default,,0000,0000,0000,,Everything goes around the Sun\Nexactly the way it is supposed to. Dialogue: 0,0:03:50.95,0:03:52.11,Default,,0000,0000,0000,,Almost. Dialogue: 0,0:03:52.13,0:03:54.31,Default,,0000,0000,0000,,So in 2003, Dialogue: 0,0:03:54.33,0:03:56.23,Default,,0000,0000,0000,,I discovered, what was at the time, Dialogue: 0,0:03:56.25,0:03:59.59,Default,,0000,0000,0000,,the most distant known object\Nin the entire Solar system. Dialogue: 0,0:03:59.98,0:04:02.39,Default,,0000,0000,0000,,It's hard not to look\Nat that lonely body out there Dialogue: 0,0:04:02.42,0:04:04.44,Default,,0000,0000,0000,,and say, oh yeah sure,\Nso Lowell was wrong, Dialogue: 0,0:04:04.46,0:04:06.37,Default,,0000,0000,0000,,there was no planet just beyond Neptune, Dialogue: 0,0:04:06.40,0:04:08.67,Default,,0000,0000,0000,,but this, this could be a new planet. Dialogue: 0,0:04:09.09,0:04:10.62,Default,,0000,0000,0000,,The real question we had was, Dialogue: 0,0:04:10.64,0:04:12.88,Default,,0000,0000,0000,,what kind of orbit\Ndoes it have around the Sun? Dialogue: 0,0:04:12.90,0:04:14.84,Default,,0000,0000,0000,,Does it go in a circle around the Sun Dialogue: 0,0:04:14.86,0:04:16.44,Default,,0000,0000,0000,,like a planet should? Dialogue: 0,0:04:16.46,0:04:20.36,Default,,0000,0000,0000,,Or is it just a typical member\Nof this icy belt of bodies Dialogue: 0,0:04:20.39,0:04:23.89,Default,,0000,0000,0000,,that got a little bit tossed outward\Nand it's now on its way back in? Dialogue: 0,0:04:24.44,0:04:26.96,Default,,0000,0000,0000,,This is precisely the question Dialogue: 0,0:04:26.98,0:04:31.24,Default,,0000,0000,0000,,the astronomers were trying\Nto answer about Uranus 200 years ago. Dialogue: 0,0:04:31.62,0:04:35.41,Default,,0000,0000,0000,,They did it by using\Noverlooked observations of Uranus Dialogue: 0,0:04:35.44,0:04:39.51,Default,,0000,0000,0000,,from 91 years before its discovery\Nto figure out its entire orbit. Dialogue: 0,0:04:39.53,0:04:41.55,Default,,0000,0000,0000,,We couldn't go quite that far back, Dialogue: 0,0:04:41.58,0:04:46.17,Default,,0000,0000,0000,,but we did find observations\Nof our object from 13 years earlier, Dialogue: 0,0:04:46.20,0:04:48.88,Default,,0000,0000,0000,,that allowed us to figure out\Nhow it went around the Sun. Dialogue: 0,0:04:48.90,0:04:50.10,Default,,0000,0000,0000,,So the question is, Dialogue: 0,0:04:50.12,0:04:52.93,Default,,0000,0000,0000,,is it in a circular orbit\Naround the Sun, like a planet, Dialogue: 0,0:04:52.96,0:04:54.33,Default,,0000,0000,0000,,or is it on its way back in, Dialogue: 0,0:04:54.36,0:04:56.28,Default,,0000,0000,0000,,like one of these typical icy bodies? Dialogue: 0,0:04:56.30,0:04:57.96,Default,,0000,0000,0000,,And the answer is Dialogue: 0,0:04:57.99,0:04:59.15,Default,,0000,0000,0000,,no. Dialogue: 0,0:04:59.17,0:05:02.06,Default,,0000,0000,0000,,It has a massively elongated orbit Dialogue: 0,0:05:02.08,0:05:05.63,Default,,0000,0000,0000,,that takes 10,000 years\Nto go around the Sun. Dialogue: 0,0:05:06.05,0:05:08.04,Default,,0000,0000,0000,,We named this object Sedna, Dialogue: 0,0:05:08.06,0:05:09.95,Default,,0000,0000,0000,,after the Inuit goddess of the sea Dialogue: 0,0:05:09.97,0:05:14.01,Default,,0000,0000,0000,,in honor of the cold, icy places\Nwhere it spends all of its time. Dialogue: 0,0:05:14.03,0:05:15.64,Default,,0000,0000,0000,,We now know that Sedna, Dialogue: 0,0:05:15.66,0:05:17.41,Default,,0000,0000,0000,,it's about a third the size of Pluto Dialogue: 0,0:05:17.44,0:05:19.61,Default,,0000,0000,0000,,and it's a relatively typical member Dialogue: 0,0:05:19.64,0:05:22.36,Default,,0000,0000,0000,,of those icy bodies out beyond Neptune. Dialogue: 0,0:05:22.38,0:05:26.23,Default,,0000,0000,0000,,Relatively typical,\Nexcept for this bizarre orbit. Dialogue: 0,0:05:26.25,0:05:28.02,Default,,0000,0000,0000,,You might look at this orbit and say, Dialogue: 0,0:05:28.05,0:05:30.78,Default,,0000,0000,0000,,"Yeah, that's bizarre,\N10,000 years to go around the Sun," Dialogue: 0,0:05:30.80,0:05:32.74,Default,,0000,0000,0000,,but that's not really the bizarre part. Dialogue: 0,0:05:32.76,0:05:34.93,Default,,0000,0000,0000,,The bizarre part is\Nthat in those 10,000 years Dialogue: 0,0:05:34.95,0:05:38.59,Default,,0000,0000,0000,,Sedna never comes close\Nto anything else in the Solar system. Dialogue: 0,0:05:38.97,0:05:41.28,Default,,0000,0000,0000,,Even at its closest approach to the Sun, Dialogue: 0,0:05:41.31,0:05:43.61,Default,,0000,0000,0000,,Sedna is further from Neptune Dialogue: 0,0:05:43.64,0:05:45.78,Default,,0000,0000,0000,,than Neptune is from the Earth. Dialogue: 0,0:05:47.05,0:05:49.16,Default,,0000,0000,0000,,If Sedna had had an orbit like this, Dialogue: 0,0:05:49.19,0:05:51.82,Default,,0000,0000,0000,,that kisses the orbit of Neptune\Nonce around the Sun, Dialogue: 0,0:05:51.85,0:05:54.58,Default,,0000,0000,0000,,that would have actually been\Nreally easy to explain. Dialogue: 0,0:05:54.90,0:05:56.63,Default,,0000,0000,0000,,That would have just been an object Dialogue: 0,0:05:56.66,0:05:58.95,Default,,0000,0000,0000,,that had been in a circular\Norbit around the Sun Dialogue: 0,0:05:58.98,0:06:00.39,Default,,0000,0000,0000,,in that region of icy bodies, Dialogue: 0,0:06:00.41,0:06:02.94,Default,,0000,0000,0000,,had gotten a little bit\Ntoo close to Neptune one time, Dialogue: 0,0:06:02.97,0:06:05.78,Default,,0000,0000,0000,,and then got slingshot out\Nand is now on its way back in. Dialogue: 0,0:06:07.35,0:06:12.06,Default,,0000,0000,0000,,But Sedna never comes close\Nto anything known in the Solar system Dialogue: 0,0:06:12.08,0:06:14.48,Default,,0000,0000,0000,,that could have given it that slingshot. Dialogue: 0,0:06:14.50,0:06:16.51,Default,,0000,0000,0000,,Neptune can't be responsible, Dialogue: 0,0:06:16.54,0:06:18.94,Default,,0000,0000,0000,,but something had to be responsible. Dialogue: 0,0:06:19.67,0:06:22.61,Default,,0000,0000,0000,,This was the first time since 1845 Dialogue: 0,0:06:22.63,0:06:27.55,Default,,0000,0000,0000,,that we saw the gravitational effects\Nof something in the outer Solar system, Dialogue: 0,0:06:27.58,0:06:29.44,Default,,0000,0000,0000,,and didn't know what it was. Dialogue: 0,0:06:30.20,0:06:32.43,Default,,0000,0000,0000,,I actually thought I knew\Nwhat the answer was. Dialogue: 0,0:06:33.14,0:06:37.14,Default,,0000,0000,0000,,Sure, it could have been some\Ndistant, giant planet Dialogue: 0,0:06:37.16,0:06:38.44,Default,,0000,0000,0000,,in the outer Solar system, Dialogue: 0,0:06:38.47,0:06:40.82,Default,,0000,0000,0000,,but by this time, that idea\Nwas so ridiculous Dialogue: 0,0:06:40.85,0:06:42.69,Default,,0000,0000,0000,,and had been so thoroughly discredited Dialogue: 0,0:06:42.71,0:06:44.51,Default,,0000,0000,0000,,that I didn't take it very seriously. Dialogue: 0,0:06:44.54,0:06:45.78,Default,,0000,0000,0000,,But 4.5 billion years ago, Dialogue: 0,0:06:45.80,0:06:50.70,Default,,0000,0000,0000,,when the Sun formed on a cocoon\Nof hundreds of other stars, Dialogue: 0,0:06:50.72,0:06:51.94,Default,,0000,0000,0000,,any one of those stars Dialogue: 0,0:06:51.97,0:06:54.64,Default,,0000,0000,0000,,could have gotten\Njust a little bit too close to Sedna Dialogue: 0,0:06:54.66,0:06:58.11,Default,,0000,0000,0000,,and perturbed it onto the orbit\Nthat it has today. Dialogue: 0,0:06:58.65,0:07:02.54,Default,,0000,0000,0000,,When that cluster of stars\Ndissipated into the galaxy, Dialogue: 0,0:07:02.56,0:07:06.34,Default,,0000,0000,0000,,the orbit of Sedna would have been\Nleft as a fossil record Dialogue: 0,0:07:06.37,0:07:08.40,Default,,0000,0000,0000,,of this earliest history of the Sun. Dialogue: 0,0:07:08.86,0:07:10.66,Default,,0000,0000,0000,,I was so excited by this idea, Dialogue: 0,0:07:10.69,0:07:12.20,Default,,0000,0000,0000,,by the idea that we could look Dialogue: 0,0:07:12.22,0:07:14.43,Default,,0000,0000,0000,,at the fossil history\Nof the birth of the Sun, Dialogue: 0,0:07:14.45,0:07:16.05,Default,,0000,0000,0000,,that I spent the next decade Dialogue: 0,0:07:16.08,0:07:18.81,Default,,0000,0000,0000,,looking for more objects\Nwith orbits like Sedna. Dialogue: 0,0:07:18.83,0:07:22.28,Default,,0000,0000,0000,,In that ten-year period, I found zero. Dialogue: 0,0:07:22.30,0:07:23.30,Default,,0000,0000,0000,,(Laughter) Dialogue: 0,0:07:23.32,0:07:26.84,Default,,0000,0000,0000,,But my colleagues Chad Trujillo\Nand Scott Sheppard, did a better job, Dialogue: 0,0:07:26.87,0:07:29.89,Default,,0000,0000,0000,,and they have now found several objects\Nwith orbits like Sedna, Dialogue: 0,0:07:29.91,0:07:31.68,Default,,0000,0000,0000,,which is super exciting. Dialogue: 0,0:07:31.70,0:07:33.24,Default,,0000,0000,0000,,But what's even more interesting Dialogue: 0,0:07:33.27,0:07:35.100,Default,,0000,0000,0000,,is that they found that all these objects Dialogue: 0,0:07:36.02,0:07:39.94,Default,,0000,0000,0000,,are not only on these distant,\Nelongated orbits, Dialogue: 0,0:07:39.97,0:07:45.32,Default,,0000,0000,0000,,they also share a common value\Nof this obscure orbital parameter Dialogue: 0,0:07:45.35,0:07:49.28,Default,,0000,0000,0000,,that in celestial mechanics we call\Nargument of perihelion. Dialogue: 0,0:07:50.24,0:07:53.20,Default,,0000,0000,0000,,When they realized it was clustered\Nin argument of perihelion, Dialogue: 0,0:07:53.22,0:07:54.97,Default,,0000,0000,0000,,they immediately jumped up and down, Dialogue: 0,0:07:54.100,0:07:57.96,Default,,0000,0000,0000,,saying it must be caused\Nby a distant, giant planet out there, Dialogue: 0,0:07:57.98,0:08:01.08,Default,,0000,0000,0000,,which is really exciting,\Nexcept it makes no sense at all. Dialogue: 0,0:08:01.10,0:08:03.64,Default,,0000,0000,0000,,Let me try to explain it\Nto you why, with an analogy. Dialogue: 0,0:08:03.66,0:08:06.93,Default,,0000,0000,0000,,Imagine a person walking down a plaza Dialogue: 0,0:08:06.96,0:08:10.30,Default,,0000,0000,0000,,and looking 45 degrees to his right side. Dialogue: 0,0:08:11.11,0:08:13.12,Default,,0000,0000,0000,,There's a lot of reasons\Nthat might happen, Dialogue: 0,0:08:13.14,0:08:15.05,Default,,0000,0000,0000,,it's super easy to explain, no big deal. Dialogue: 0,0:08:15.08,0:08:16.96,Default,,0000,0000,0000,,Imagine now many different people, Dialogue: 0,0:08:16.98,0:08:20.87,Default,,0000,0000,0000,,all walking in different\Ndirections across the plaza, Dialogue: 0,0:08:20.90,0:08:24.20,Default,,0000,0000,0000,,but all looking 45 degrees\Nto the direction that they're moving. Dialogue: 0,0:08:24.22,0:08:26.24,Default,,0000,0000,0000,,Everybody's moving\Nin different directions, Dialogue: 0,0:08:26.26,0:08:28.34,Default,,0000,0000,0000,,everybody's looking\Nin different directions, Dialogue: 0,0:08:28.36,0:08:31.73,Default,,0000,0000,0000,,but they're all looking 45 degrees\Nto the direction of motion. Dialogue: 0,0:08:31.75,0:08:33.85,Default,,0000,0000,0000,,What could cause something like that? Dialogue: 0,0:08:34.93,0:08:36.15,Default,,0000,0000,0000,,I have no idea. Dialogue: 0,0:08:36.17,0:08:39.94,Default,,0000,0000,0000,,It's very difficult to think of any reason\Nthat that would happen. Dialogue: 0,0:08:39.97,0:08:41.29,Default,,0000,0000,0000,,(Laughter) Dialogue: 0,0:08:41.32,0:08:44.17,Default,,0000,0000,0000,,And this is essentially\Nwhat that clustering Dialogue: 0,0:08:44.20,0:08:47.21,Default,,0000,0000,0000,,in argument of perihelion was telling us. Dialogue: 0,0:08:47.63,0:08:51.20,Default,,0000,0000,0000,,Scientists were generally baffled\Nand they assumed it must just be a fluke Dialogue: 0,0:08:51.22,0:08:52.54,Default,,0000,0000,0000,,and some bad observations. Dialogue: 0,0:08:52.57,0:08:54.35,Default,,0000,0000,0000,,They told the astronomers, Dialogue: 0,0:08:54.37,0:08:56.04,Default,,0000,0000,0000,,"Do better measurements." Dialogue: 0,0:08:56.78,0:08:59.89,Default,,0000,0000,0000,,I actually took a very careful look\Nat those measurements, though, Dialogue: 0,0:08:59.92,0:09:01.12,Default,,0000,0000,0000,,and they were right. Dialogue: 0,0:09:01.15,0:09:03.12,Default,,0000,0000,0000,,These objects really did all share Dialogue: 0,0:09:03.14,0:09:05.59,Default,,0000,0000,0000,,a common value of argument of perihelion, Dialogue: 0,0:09:05.62,0:09:07.01,Default,,0000,0000,0000,,and they shouldn't. Dialogue: 0,0:09:07.03,0:09:09.23,Default,,0000,0000,0000,,Something had to be causing that. Dialogue: 0,0:09:11.14,0:09:15.42,Default,,0000,0000,0000,,The final piece of the puzzle\Ncame into place in 2016, Dialogue: 0,0:09:15.44,0:09:17.99,Default,,0000,0000,0000,,when my colleague, Konstantin Batygin, Dialogue: 0,0:09:18.01,0:09:20.63,Default,,0000,0000,0000,,who works three doors down from me, and I Dialogue: 0,0:09:20.66,0:09:23.27,Default,,0000,0000,0000,,realized that the reason\Nthat everybody was baffled Dialogue: 0,0:09:23.29,0:09:27.63,Default,,0000,0000,0000,,was because argument of perihelion\Nwas only part of the story. Dialogue: 0,0:09:28.02,0:09:30.04,Default,,0000,0000,0000,,If you look at these\Nobjects the right way, Dialogue: 0,0:09:30.06,0:09:34.17,Default,,0000,0000,0000,,they are all actually lined up\Nin space in the same direction, Dialogue: 0,0:09:34.20,0:09:37.94,Default,,0000,0000,0000,,and they're all tilted in space\Nin the same direction. Dialogue: 0,0:09:37.96,0:09:42.32,Default,,0000,0000,0000,,It's as if all those people on the plaza\Nare all walking in the same direction Dialogue: 0,0:09:42.34,0:09:45.44,Default,,0000,0000,0000,,and they're all looking\N45 degrees to the right side. Dialogue: 0,0:09:45.81,0:09:46.100,Default,,0000,0000,0000,,That's easy to explain. Dialogue: 0,0:09:47.02,0:09:49.22,Default,,0000,0000,0000,,They're all looking at something. Dialogue: 0,0:09:49.58,0:09:53.70,Default,,0000,0000,0000,,These objects in the outer Solar system\Nare all reacting to something. Dialogue: 0,0:09:54.98,0:09:56.13,Default,,0000,0000,0000,,But what? Dialogue: 0,0:09:56.74,0:09:59.73,Default,,0000,0000,0000,,Konstantin and I spent a year Dialogue: 0,0:09:59.75,0:10:04.56,Default,,0000,0000,0000,,trying to come up with any explanation\Nother than a distant, giant planet Dialogue: 0,0:10:04.58,0:10:05.83,Default,,0000,0000,0000,,in the outer Solar system. Dialogue: 0,0:10:05.86,0:10:11.31,Default,,0000,0000,0000,,We did not want to be the 33rd and 34th\Npeople in history to propose this planet Dialogue: 0,0:10:11.33,0:10:13.66,Default,,0000,0000,0000,,to yet again be told we were wrong. Dialogue: 0,0:10:14.78,0:10:16.54,Default,,0000,0000,0000,,But after a year, Dialogue: 0,0:10:16.57,0:10:17.88,Default,,0000,0000,0000,,there was really no choice. Dialogue: 0,0:10:17.90,0:10:20.04,Default,,0000,0000,0000,,We could come up with no other explanation Dialogue: 0,0:10:20.07,0:10:22.62,Default,,0000,0000,0000,,other than that that there is a distant, Dialogue: 0,0:10:22.64,0:10:25.88,Default,,0000,0000,0000,,massive planet on an elongated orbit, Dialogue: 0,0:10:25.91,0:10:27.99,Default,,0000,0000,0000,,inclined to the rest of the Solar system, Dialogue: 0,0:10:28.01,0:10:30.73,Default,,0000,0000,0000,,that is forcing these patterns\Nfor these objects Dialogue: 0,0:10:30.75,0:10:32.48,Default,,0000,0000,0000,,in the outer Solar system. Dialogue: 0,0:10:32.79,0:10:34.92,Default,,0000,0000,0000,,Guess what else a planet like this does. Dialogue: 0,0:10:34.94,0:10:36.82,Default,,0000,0000,0000,,Remember that strange orbit of Sedna, Dialogue: 0,0:10:36.85,0:10:39.78,Default,,0000,0000,0000,,how it was kind of pulled away\Nfrom the Sun in one direction? Dialogue: 0,0:10:39.81,0:10:42.90,Default,,0000,0000,0000,,A planet like this would make\Norbits like that all day long. Dialogue: 0,0:10:43.52,0:10:45.52,Default,,0000,0000,0000,,We knew we were onto something. Dialogue: 0,0:10:45.87,0:10:48.48,Default,,0000,0000,0000,,So this brings us to today. Dialogue: 0,0:10:48.86,0:10:53.07,Default,,0000,0000,0000,,We are basically 1845, Paris. Dialogue: 0,0:10:53.10,0:10:54.25,Default,,0000,0000,0000,,(Laughter) Dialogue: 0,0:10:54.27,0:10:59.62,Default,,0000,0000,0000,,We see the gravitational effects\Nof a distant, giant planet, Dialogue: 0,0:10:59.64,0:11:01.87,Default,,0000,0000,0000,,and we are trying to work the calculations Dialogue: 0,0:11:01.90,0:11:04.88,Default,,0000,0000,0000,,to tell us where to look,\Nto point our telescopes, Dialogue: 0,0:11:04.90,0:11:06.11,Default,,0000,0000,0000,,to find this planet. Dialogue: 0,0:11:06.13,0:11:08.42,Default,,0000,0000,0000,,We've done massive suits\Nof computer simulations, Dialogue: 0,0:11:09.31,0:11:11.23,Default,,0000,0000,0000,,massive months of analytic calculations, Dialogue: 0,0:11:11.25,0:11:13.82,Default,,0000,0000,0000,,and here's what I cal tell you so far. Dialogue: 0,0:11:13.85,0:11:17.01,Default,,0000,0000,0000,,First, this planet,\Nwhich we call Planet Nine, Dialogue: 0,0:11:17.04,0:11:19.62,Default,,0000,0000,0000,,because that's what it is, Dialogue: 0,0:11:20.77,0:11:23.100,Default,,0000,0000,0000,,Planet Nine is six times\Nthe mass of the Earth. Dialogue: 0,0:11:24.02,0:11:26.27,Default,,0000,0000,0000,,This is no slightly-smaller-than-Pluto, Dialogue: 0,0:11:26.29,0:11:29.04,Default,,0000,0000,0000,,let's-all-argue-about\Nwhether-it's-a-planet-or-not thing. Dialogue: 0,0:11:29.06,0:11:32.37,Default,,0000,0000,0000,,This is the fifth largest planet\Nin our entire Solar system. Dialogue: 0,0:11:32.40,0:11:36.04,Default,,0000,0000,0000,,For context, let me show you\Nthe sizes of the planets. Dialogue: 0,0:11:36.06,0:11:39.63,Default,,0000,0000,0000,,In the back there,\Nyou can the massive Jupiter and Saturn. Dialogue: 0,0:11:40.20,0:11:42.84,Default,,0000,0000,0000,,Next to them, a little bit smaller,\NUranus and Neptune. Dialogue: 0,0:11:42.86,0:11:46.36,Default,,0000,0000,0000,,Up in the corner, the terrestrial planets,\NMercury, Venus, Earth and Mars. Dialogue: 0,0:11:46.38,0:11:47.73,Default,,0000,0000,0000,,You can even see that belt Dialogue: 0,0:11:47.76,0:11:50.88,Default,,0000,0000,0000,,of icy bodies beyond Neptune,\Nof which Pluto is a member, Dialogue: 0,0:11:50.90,0:11:52.77,Default,,0000,0000,0000,,good luck figuring out which one it is. Dialogue: 0,0:11:52.80,0:11:55.21,Default,,0000,0000,0000,,And here is Planet Nine. Dialogue: 0,0:11:56.58,0:11:58.64,Default,,0000,0000,0000,,Planet Nine is big. Dialogue: 0,0:11:59.05,0:12:00.22,Default,,0000,0000,0000,,Planet Nine is so big, Dialogue: 0,0:12:00.24,0:12:02.85,Default,,0000,0000,0000,,you should probably wonder\Nwhy haven't we found it yet. Dialogue: 0,0:12:02.87,0:12:04.11,Default,,0000,0000,0000,,Well, Planet Nine is big, Dialogue: 0,0:12:04.13,0:12:06.35,Default,,0000,0000,0000,,but it's also really, really far away. Dialogue: 0,0:12:06.37,0:12:11.04,Default,,0000,0000,0000,,It's something like\N15 times further away than Neptune. Dialogue: 0,0:12:11.07,0:12:14.35,Default,,0000,0000,0000,,And that makes it about 50,000 times\Nfainter than Neptune. Dialogue: 0,0:12:14.37,0:12:17.32,Default,,0000,0000,0000,,And also, the sky is a really big place. Dialogue: 0,0:12:17.34,0:12:19.48,Default,,0000,0000,0000,,We've narrowed down where we think it is Dialogue: 0,0:12:19.50,0:12:22.04,Default,,0000,0000,0000,,to a relatively small area of the sky, Dialogue: 0,0:12:22.06,0:12:23.92,Default,,0000,0000,0000,,but it would still take us years Dialogue: 0,0:12:23.94,0:12:26.32,Default,,0000,0000,0000,,to systematically cover\Nthe area of the sky Dialogue: 0,0:12:26.35,0:12:28.19,Default,,0000,0000,0000,,with the large telescopes that we need Dialogue: 0,0:12:28.22,0:12:31.10,Default,,0000,0000,0000,,to see something that's\Nthis far away and this faint. Dialogue: 0,0:12:31.47,0:12:33.99,Default,,0000,0000,0000,,Luckily, we might not have to. Dialogue: 0,0:12:34.73,0:12:39.62,Default,,0000,0000,0000,,Just like Bouvard used\Nunrecognized observations of Uranus Dialogue: 0,0:12:39.64,0:12:42.39,Default,,0000,0000,0000,,from 91 years before its discovery, Dialogue: 0,0:12:42.41,0:12:46.19,Default,,0000,0000,0000,,I bet that there are unrecognized images Dialogue: 0,0:12:46.22,0:12:49.08,Default,,0000,0000,0000,,that show the location of Planet Nine. Dialogue: 0,0:12:49.98,0:12:53.06,Default,,0000,0000,0000,,It's going to be a massive\Ncomputational undertaking Dialogue: 0,0:12:53.08,0:12:55.39,Default,,0000,0000,0000,,to go through all of the old data, Dialogue: 0,0:12:55.41,0:12:58.33,Default,,0000,0000,0000,,and pick out that one faint moving planet. Dialogue: 0,0:12:59.28,0:13:00.64,Default,,0000,0000,0000,,But we're underway. Dialogue: 0,0:13:00.66,0:13:02.99,Default,,0000,0000,0000,,And I think we're getting close. Dialogue: 0,0:13:03.01,0:13:05.51,Default,,0000,0000,0000,,So I would say, get ready. Dialogue: 0,0:13:05.54,0:13:09.51,Default,,0000,0000,0000,,We are not going to match Le Verrier's Dialogue: 0,0:13:09.54,0:13:10.70,Default,,0000,0000,0000,,"make a prediction, Dialogue: 0,0:13:10.73,0:13:12.63,Default,,0000,0000,0000,,have the planet found in a single night Dialogue: 0,0:13:12.66,0:13:14.92,Default,,0000,0000,0000,,that close to where\Nyou predicted it" record. Dialogue: 0,0:13:14.94,0:13:18.88,Default,,0000,0000,0000,,But I do bet that within\Nthe next couple of years Dialogue: 0,0:13:18.91,0:13:21.32,Default,,0000,0000,0000,,some astronomer somewhere Dialogue: 0,0:13:21.34,0:13:23.57,Default,,0000,0000,0000,,will find a faint point of light, Dialogue: 0,0:13:23.60,0:13:25.87,Default,,0000,0000,0000,,slowly moving across the sky Dialogue: 0,0:13:25.89,0:13:29.17,Default,,0000,0000,0000,,and triumphantly announce\Nthe discovery of a new, Dialogue: 0,0:13:29.20,0:13:31.64,Default,,0000,0000,0000,,and quite possibly not the last, Dialogue: 0,0:13:31.66,0:13:33.79,Default,,0000,0000,0000,,real planet of our Solar system. Dialogue: 0,0:13:34.18,0:13:35.33,Default,,0000,0000,0000,,Thank you. Dialogue: 0,0:13:35.36,0:13:38.88,Default,,0000,0000,0000,,(Applause)