[Script Info]
Title: 
[Events]
Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text
Dialogue: 0,0:00:00.96,0:00:04.07,Default,,0000,0000,0000,,I'm here to tell you\Nabout the real search for alien life.
Dialogue: 0,0:00:04.68,0:00:07.91,Default,,0000,0000,0000,,Not little green humanoids\Narriving in shiny UFOs,
Dialogue: 0,0:00:07.93,0:00:09.65,Default,,0000,0000,0000,,although that would be nice.
Dialogue: 0,0:00:09.68,0:00:12.96,Default,,0000,0000,0000,,But it's the search for planets\Norbiting stars far away.
Dialogue: 0,0:00:13.92,0:00:15.76,Default,,0000,0000,0000,,Every star in our sky is a sun.
Dialogue: 0,0:00:15.78,0:00:17.16,Default,,0000,0000,0000,,And if our sun has planets --
Dialogue: 0,0:00:17.19,0:00:19.68,Default,,0000,0000,0000,,Mercury, Venus, Earth, Mars, etc.,
Dialogue: 0,0:00:19.71,0:00:22.14,Default,,0000,0000,0000,,surely those other stars\Nshould have planets also,
Dialogue: 0,0:00:22.17,0:00:23.43,Default,,0000,0000,0000,,and they do.
Dialogue: 0,0:00:23.46,0:00:24.87,Default,,0000,0000,0000,,And in the last two decades,
Dialogue: 0,0:00:24.89,0:00:27.79,Default,,0000,0000,0000,,astronomers have found\Nthousands of exoplanets.
Dialogue: 0,0:00:28.50,0:00:31.31,Default,,0000,0000,0000,,Our night sky is literally\Nteeming with exoplanets.
Dialogue: 0,0:00:31.34,0:00:32.89,Default,,0000,0000,0000,,We know, statistically speaking,
Dialogue: 0,0:00:32.91,0:00:35.41,Default,,0000,0000,0000,,that every star has at least one planet.
Dialogue: 0,0:00:35.98,0:00:37.96,Default,,0000,0000,0000,,And in the search for planets,
Dialogue: 0,0:00:37.98,0:00:40.75,Default,,0000,0000,0000,,and in the future,\Nplanets that might be like Earth,
Dialogue: 0,0:00:40.78,0:00:42.14,Default,,0000,0000,0000,,we're able to help address
Dialogue: 0,0:00:42.17,0:00:45.02,Default,,0000,0000,0000,,some of the most amazing\Nand mysterious questions
Dialogue: 0,0:00:45.04,0:00:47.61,Default,,0000,0000,0000,,that have faced humankind for centuries.
Dialogue: 0,0:00:47.64,0:00:48.88,Default,,0000,0000,0000,,Why are we here?
Dialogue: 0,0:00:49.22,0:00:50.89,Default,,0000,0000,0000,,Why does our universe exist?
Dialogue: 0,0:00:51.48,0:00:53.52,Default,,0000,0000,0000,,How did Earth form and evolve?
Dialogue: 0,0:00:53.91,0:00:56.90,Default,,0000,0000,0000,,How and why did life originate\Nand populate our planet?
Dialogue: 0,0:00:57.66,0:01:00.72,Default,,0000,0000,0000,,The second question\Nthat we often think about is:
Dialogue: 0,0:01:00.74,0:01:02.03,Default,,0000,0000,0000,,Are we alone?
Dialogue: 0,0:01:02.91,0:01:04.30,Default,,0000,0000,0000,,Is there life out there?
Dialogue: 0,0:01:05.11,0:01:06.60,Default,,0000,0000,0000,,Who is out there?
Dialogue: 0,0:01:07.78,0:01:10.79,Default,,0000,0000,0000,,You know, this question has been around\Nfor thousands of years,
Dialogue: 0,0:01:10.81,0:01:13.23,Default,,0000,0000,0000,,since at least the time\Nof the Greek philosophers.
Dialogue: 0,0:01:13.25,0:01:15.80,Default,,0000,0000,0000,,But I'm here to tell you\Njust how close we're getting
Dialogue: 0,0:01:15.82,0:01:18.71,Default,,0000,0000,0000,,to finding out the answer\Nto this question.
Dialogue: 0,0:01:18.73,0:01:22.94,Default,,0000,0000,0000,,It's the first time in human history\Nthat this really is within reach for us.
Dialogue: 0,0:01:23.29,0:01:26.27,Default,,0000,0000,0000,,Now when I think about the possibilities\Nfor life out there,
Dialogue: 0,0:01:26.30,0:01:30.38,Default,,0000,0000,0000,,I think of the fact that our sun\Nis but one of many stars.
Dialogue: 0,0:01:30.82,0:01:32.70,Default,,0000,0000,0000,,This is a photograph of a real galaxy,
Dialogue: 0,0:01:32.73,0:01:35.17,Default,,0000,0000,0000,,we think our Milky Way\Nlooks like this galaxy.
Dialogue: 0,0:01:35.20,0:01:36.84,Default,,0000,0000,0000,,It's a collection of bound stars.
Dialogue: 0,0:01:36.86,0:01:41.25,Default,,0000,0000,0000,,But our [sun] is one\Nof hundreds of billions of stars
Dialogue: 0,0:01:41.27,0:01:45.60,Default,,0000,0000,0000,,and our galaxy is one of upwards\Nof hundreds of billions of galaxies.
Dialogue: 0,0:01:46.71,0:01:49.47,Default,,0000,0000,0000,,Knowing that small planets\Nare very common,
Dialogue: 0,0:01:49.50,0:01:50.77,Default,,0000,0000,0000,,you can just do the math.
Dialogue: 0,0:01:51.42,0:01:55.42,Default,,0000,0000,0000,,And there are just so many stars\Nand so many planets out there,
Dialogue: 0,0:01:55.45,0:01:58.14,Default,,0000,0000,0000,,that surely, there must be life\Nsomewhere out there.
Dialogue: 0,0:01:59.06,0:02:02.48,Default,,0000,0000,0000,,Well, the biologists get furious\Nwith me for saying that,
Dialogue: 0,0:02:02.50,0:02:05.95,Default,,0000,0000,0000,,because we have absolutely no evidence\Nfor life beyond Earth yet.
Dialogue: 0,0:02:06.98,0:02:11.77,Default,,0000,0000,0000,,Well, if we were able to look\Nat our galaxy from the outside
Dialogue: 0,0:02:11.79,0:02:14.00,Default,,0000,0000,0000,,and zoom in to where our sun is,
Dialogue: 0,0:02:14.03,0:02:15.59,Default,,0000,0000,0000,,we see a real map of the stars.
Dialogue: 0,0:02:16.05,0:02:19.07,Default,,0000,0000,0000,,And the highlighted stars\Nare those with known exoplanets.
Dialogue: 0,0:02:19.74,0:02:21.93,Default,,0000,0000,0000,,This is really just\Nthe tip of the iceberg.
Dialogue: 0,0:02:22.64,0:02:26.28,Default,,0000,0000,0000,,Here, this animation is zooming in\Nonto our solar system.
Dialogue: 0,0:02:26.87,0:02:28.36,Default,,0000,0000,0000,,And you'll see here the planets
Dialogue: 0,0:02:28.38,0:02:31.21,Default,,0000,0000,0000,,as well as some spacecraft\Nthat are also orbiting our sun.
Dialogue: 0,0:02:32.97,0:02:36.33,Default,,0000,0000,0000,,Now if we can imagine going\Nto the West Coast of North America,
Dialogue: 0,0:02:36.36,0:02:38.48,Default,,0000,0000,0000,,and looking out at the night sky,
Dialogue: 0,0:02:38.51,0:02:40.78,Default,,0000,0000,0000,,here's what we'd see on a spring night.
Dialogue: 0,0:02:40.81,0:02:42.82,Default,,0000,0000,0000,,And you can see\Nthe constellations overlaid
Dialogue: 0,0:02:42.84,0:02:45.11,Default,,0000,0000,0000,,and again, so many stars with planets.
Dialogue: 0,0:02:45.14,0:02:49.33,Default,,0000,0000,0000,,There's a special patch of the sky\Nwhere we have thousands of planets.
Dialogue: 0,0:02:49.35,0:02:53.04,Default,,0000,0000,0000,,This is where the Kepler Space Telescope\Nfocused for many years.
Dialogue: 0,0:02:53.58,0:02:58.25,Default,,0000,0000,0000,,Let's zoom in and look\Nat one of the favorite exoplanets.
Dialogue: 0,0:02:58.86,0:03:02.12,Default,,0000,0000,0000,,This star is called Kepler-186f.
Dialogue: 0,0:03:02.53,0:03:04.73,Default,,0000,0000,0000,,It's a system of about five planets.
Dialogue: 0,0:03:04.75,0:03:08.58,Default,,0000,0000,0000,,And by the way, most of these exoplanets,\Nwe don't know too much about.
Dialogue: 0,0:03:08.60,0:03:11.58,Default,,0000,0000,0000,,We know their size, and their orbit\Nand things like that.
Dialogue: 0,0:03:11.61,0:03:15.57,Default,,0000,0000,0000,,But there's a very special planet\Nhere called Kepler-186f.
Dialogue: 0,0:03:15.59,0:03:19.70,Default,,0000,0000,0000,,This planet is in a zone\Nthat is not too far from the star,
Dialogue: 0,0:03:19.72,0:03:22.98,Default,,0000,0000,0000,,so that the temperature\Nmay be just right for life.
Dialogue: 0,0:03:23.00,0:03:26.04,Default,,0000,0000,0000,,Here, the artist's conception\Nis just zooming in
Dialogue: 0,0:03:26.06,0:03:28.33,Default,,0000,0000,0000,,and showing you what that planet\Nmight be like.
Dialogue: 0,0:03:31.07,0:03:36.68,Default,,0000,0000,0000,,So, many people have this\Nromantic notion of astronomers
Dialogue: 0,0:03:36.70,0:03:40.26,Default,,0000,0000,0000,,going to the telescope\Non a lonely mountaintop
Dialogue: 0,0:03:40.28,0:03:43.83,Default,,0000,0000,0000,,and looking at the spectacular night sky\Nthrough a big telescope.
Dialogue: 0,0:03:43.85,0:03:47.22,Default,,0000,0000,0000,,But actually, we just work\Non our computers like everyone else,
Dialogue: 0,0:03:47.25,0:03:51.07,Default,,0000,0000,0000,,and we get our data by email\Nor downloading from a database.
Dialogue: 0,0:03:51.10,0:03:53.62,Default,,0000,0000,0000,,So instead of coming here to tell you
Dialogue: 0,0:03:53.64,0:03:56.78,Default,,0000,0000,0000,,about the somewhat tedious nature\Nof the data and data analysis
Dialogue: 0,0:03:56.80,0:03:58.87,Default,,0000,0000,0000,,and the complex computer models we make,
Dialogue: 0,0:03:58.89,0:04:01.09,Default,,0000,0000,0000,,I have a different way\Nto try to explain to you
Dialogue: 0,0:04:01.11,0:04:03.76,Default,,0000,0000,0000,,some of the things\Nthat we're thinking about exoplanets.
Dialogue: 0,0:04:03.78,0:04:04.95,Default,,0000,0000,0000,,Here's a travel poster:
Dialogue: 0,0:04:04.97,0:04:07.29,Default,,0000,0000,0000,,"Kepler-186f:
Dialogue: 0,0:04:07.32,0:04:10.03,Default,,0000,0000,0000,,Where the grass is always redder\Non the other side."
Dialogue: 0,0:04:10.05,0:04:13.78,Default,,0000,0000,0000,,That's because Kepler-186f\Norbits a red star,
Dialogue: 0,0:04:13.81,0:04:16.50,Default,,0000,0000,0000,,and we're just speculating\Nthat perhaps the plants there,
Dialogue: 0,0:04:16.52,0:04:19.14,Default,,0000,0000,0000,,if there is vegetation\Nthat does photosynthesis,
Dialogue: 0,0:04:19.16,0:04:21.11,Default,,0000,0000,0000,,it has different pigments and looks red.
Dialogue: 0,0:04:22.14,0:04:26.50,Default,,0000,0000,0000,,"Enjoy the gravity on HD 40307g,
Dialogue: 0,0:04:26.52,0:04:27.98,Default,,0000,0000,0000,,a Super-Earth."
Dialogue: 0,0:04:28.00,0:04:30.16,Default,,0000,0000,0000,,This planet is more massive than Earth
Dialogue: 0,0:04:30.18,0:04:31.90,Default,,0000,0000,0000,,and has a higher surface gravity.
Dialogue: 0,0:04:32.33,0:04:35.23,Default,,0000,0000,0000,,"Relax on Kepler-16b,
Dialogue: 0,0:04:35.25,0:04:37.15,Default,,0000,0000,0000,,where your shadow always has company."
Dialogue: 0,0:04:37.17,0:04:39.13,Default,,0000,0000,0000,,(Laughter)
Dialogue: 0,0:04:39.16,0:04:43.34,Default,,0000,0000,0000,,We know of a dozen planets\Nthat orbit two stars,
Dialogue: 0,0:04:43.36,0:04:45.48,Default,,0000,0000,0000,,and there's likely many more out there.
Dialogue: 0,0:04:45.51,0:04:47.47,Default,,0000,0000,0000,,If we could visit one of those planets,
Dialogue: 0,0:04:47.49,0:04:49.38,Default,,0000,0000,0000,,you literally would see two sunsets
Dialogue: 0,0:04:49.40,0:04:50.66,Default,,0000,0000,0000,,and have two shadows.
Dialogue: 0,0:04:51.48,0:04:53.90,Default,,0000,0000,0000,,So actually, science fiction\Ngot some things right.
Dialogue: 0,0:04:53.92,0:04:55.13,Default,,0000,0000,0000,,Tatooine from Star Wars.
Dialogue: 0,0:04:56.05,0:04:58.34,Default,,0000,0000,0000,,And I have a couple of other\Nfavorite exoplanets
Dialogue: 0,0:04:58.37,0:04:59.56,Default,,0000,0000,0000,,to tell you about.
Dialogue: 0,0:04:59.59,0:05:01.12,Default,,0000,0000,0000,,This one is Kepler-10b,
Dialogue: 0,0:05:01.14,0:05:03.13,Default,,0000,0000,0000,,it's a hot, hot planet.
Dialogue: 0,0:05:03.64,0:05:06.58,Default,,0000,0000,0000,,It orbits over 50 times closer to its star
Dialogue: 0,0:05:06.60,0:05:08.77,Default,,0000,0000,0000,,than our Earth does to our sun.
Dialogue: 0,0:05:08.79,0:05:10.37,Default,,0000,0000,0000,,And actually, it's so hot,
Dialogue: 0,0:05:10.40,0:05:13.03,Default,,0000,0000,0000,,we can't visit any\Nof these planets, but if we could,
Dialogue: 0,0:05:13.05,0:05:15.03,Default,,0000,0000,0000,,we would melt long before we got there.
Dialogue: 0,0:05:15.05,0:05:17.38,Default,,0000,0000,0000,,We think the surface\Nis hot enough to melt rock
Dialogue: 0,0:05:17.40,0:05:18.83,Default,,0000,0000,0000,,and has liquid lava lakes.
Dialogue: 0,0:05:19.46,0:05:21.04,Default,,0000,0000,0000,,Gliese 1214b.
Dialogue: 0,0:05:21.06,0:05:23.16,Default,,0000,0000,0000,,This planet, we know the mass and the size
Dialogue: 0,0:05:23.19,0:05:24.78,Default,,0000,0000,0000,,and it has a fairly low density.
Dialogue: 0,0:05:24.80,0:05:25.100,Default,,0000,0000,0000,,It's somewhat warm.
Dialogue: 0,0:05:26.05,0:05:28.74,Default,,0000,0000,0000,,We actually don't know\Nreally anything about this planet,
Dialogue: 0,0:05:28.76,0:05:31.27,Default,,0000,0000,0000,,but one possibility\Nis that it's a water world,
Dialogue: 0,0:05:31.29,0:05:34.80,Default,,0000,0000,0000,,like a scaled-up version\Nof one of Jupiter's icy moons
Dialogue: 0,0:05:34.82,0:05:37.30,Default,,0000,0000,0000,,that might be 50 percent water by mass.
Dialogue: 0,0:05:37.33,0:05:40.29,Default,,0000,0000,0000,,And in this case, it would have\Na thick steam atmosphere
Dialogue: 0,0:05:40.31,0:05:42.17,Default,,0000,0000,0000,,overlaying an ocean,
Dialogue: 0,0:05:42.19,0:05:43.70,Default,,0000,0000,0000,,not of liquid water,
Dialogue: 0,0:05:43.73,0:05:46.73,Default,,0000,0000,0000,,but of an exotic form\Nof water, a superfluid --
Dialogue: 0,0:05:46.76,0:05:48.75,Default,,0000,0000,0000,,not quite a gas, not quite a liquid.
Dialogue: 0,0:05:48.77,0:05:50.37,Default,,0000,0000,0000,,And under that wouldn't be rock,
Dialogue: 0,0:05:50.39,0:05:51.99,Default,,0000,0000,0000,,but a form of high-pressure ice,
Dialogue: 0,0:05:52.01,0:05:53.29,Default,,0000,0000,0000,,like ice IX.
Dialogue: 0,0:05:54.59,0:05:56.77,Default,,0000,0000,0000,,So out of all these planets out there,
Dialogue: 0,0:05:56.79,0:06:00.01,Default,,0000,0000,0000,,and the variety\Nis just simply astonishing,
Dialogue: 0,0:06:00.03,0:06:05.16,Default,,0000,0000,0000,,we mostly want to find the planets\Nthat are Goldilocks planets, we call them.
Dialogue: 0,0:06:05.18,0:06:07.10,Default,,0000,0000,0000,,Not too big, not too small,
Dialogue: 0,0:06:07.12,0:06:08.97,Default,,0000,0000,0000,,not too hot, not too cold --
Dialogue: 0,0:06:08.100,0:06:10.34,Default,,0000,0000,0000,,but just right for life.
Dialogue: 0,0:06:10.66,0:06:12.78,Default,,0000,0000,0000,,But to do that,\Nwe'd have to be able to look
Dialogue: 0,0:06:12.80,0:06:14.13,Default,,0000,0000,0000,,at the planet's atmosphere,
Dialogue: 0,0:06:14.16,0:06:16.95,Default,,0000,0000,0000,,because the atmosphere\Nacts like a blanket trapping heat --
Dialogue: 0,0:06:16.98,0:06:18.31,Default,,0000,0000,0000,,the greenhouse effect.
Dialogue: 0,0:06:18.34,0:06:21.16,Default,,0000,0000,0000,,We have to be able to assess\Nthe greenhouse gases
Dialogue: 0,0:06:21.18,0:06:22.33,Default,,0000,0000,0000,,on other planets.
Dialogue: 0,0:06:23.17,0:06:25.29,Default,,0000,0000,0000,,Well, science fiction\Ngot some things wrong.
Dialogue: 0,0:06:25.80,0:06:27.19,Default,,0000,0000,0000,,The Star Trek Enterprise
Dialogue: 0,0:06:27.21,0:06:30.84,Default,,0000,0000,0000,,had to travel vast distances\Nat incredible speeds
Dialogue: 0,0:06:30.86,0:06:32.59,Default,,0000,0000,0000,,to orbit other planets
Dialogue: 0,0:06:32.61,0:06:36.59,Default,,0000,0000,0000,,so that First Officer Spock\Ncould analyze the atmosphere
Dialogue: 0,0:06:36.61,0:06:38.58,Default,,0000,0000,0000,,to see if the planet was habitable
Dialogue: 0,0:06:38.60,0:06:40.27,Default,,0000,0000,0000,,or if there were lifeforms there.
Dialogue: 0,0:06:40.74,0:06:43.24,Default,,0000,0000,0000,,Well, we don't need\Nto travel at warp speeds
Dialogue: 0,0:06:43.26,0:06:45.39,Default,,0000,0000,0000,,to see other planet atmospheres,
Dialogue: 0,0:06:45.41,0:06:48.20,Default,,0000,0000,0000,,although I don't want to dissuade\Nany budding engineers
Dialogue: 0,0:06:48.22,0:06:50.14,Default,,0000,0000,0000,,from figuring out how to do that.
Dialogue: 0,0:06:50.17,0:06:52.46,Default,,0000,0000,0000,,We actually can and do study\Nplanet atmospheres
Dialogue: 0,0:06:52.48,0:06:54.10,Default,,0000,0000,0000,,from here, from Earth orbit.
Dialogue: 0,0:06:54.12,0:06:57.30,Default,,0000,0000,0000,,This is a picture, a photograph\Nof the Hubble Space Telescope
Dialogue: 0,0:06:57.32,0:07:00.07,Default,,0000,0000,0000,,taken by the shuttle Atlantis\Nas it was departing
Dialogue: 0,0:07:00.10,0:07:02.33,Default,,0000,0000,0000,,after the last\Nhuman space flight to Hubble.
Dialogue: 0,0:07:02.36,0:07:04.24,Default,,0000,0000,0000,,They installed a new camera, actually,
Dialogue: 0,0:07:04.27,0:07:06.41,Default,,0000,0000,0000,,that we use for exoplanet atmospheres.
Dialogue: 0,0:07:06.44,0:07:11.34,Default,,0000,0000,0000,,And so far, we've been able to study\Ndozens of exoplanet atmospheres,
Dialogue: 0,0:07:11.37,0:07:13.49,Default,,0000,0000,0000,,about six of them in great detail.
Dialogue: 0,0:07:13.51,0:07:15.69,Default,,0000,0000,0000,,But those are not\Nsmall planets like Earth.
Dialogue: 0,0:07:15.71,0:07:18.10,Default,,0000,0000,0000,,They're big, hot planets\Nthat are easy to see.
Dialogue: 0,0:07:18.13,0:07:19.37,Default,,0000,0000,0000,,We're not ready,
Dialogue: 0,0:07:19.39,0:07:23.76,Default,,0000,0000,0000,,we don't have the right technology yet\Nto study small exoplanets.
Dialogue: 0,0:07:24.11,0:07:25.26,Default,,0000,0000,0000,,But nevertheless,
Dialogue: 0,0:07:25.29,0:07:29.18,Default,,0000,0000,0000,,I wanted to try to explain to you\Nhow we study exoplanet atmospheres.
Dialogue: 0,0:07:29.65,0:07:31.87,Default,,0000,0000,0000,,I want you to imagine,\Nfor a moment, a rainbow.
Dialogue: 0,0:07:32.53,0:07:35.28,Default,,0000,0000,0000,,And if we could look\Nat this rainbow closely,
Dialogue: 0,0:07:35.30,0:07:37.97,Default,,0000,0000,0000,,we would see that some\Ndark lines are missing.
Dialogue: 0,0:07:39.13,0:07:40.55,Default,,0000,0000,0000,,And here's our sun,
Dialogue: 0,0:07:40.57,0:07:42.34,Default,,0000,0000,0000,,the white light of our sun split up,
Dialogue: 0,0:07:42.36,0:07:44.65,Default,,0000,0000,0000,,not by raindrops, but by a spectrograph.
Dialogue: 0,0:07:44.67,0:07:47.12,Default,,0000,0000,0000,,And you can see\Nall these dark, vertical lines.
Dialogue: 0,0:07:47.15,0:07:48.98,Default,,0000,0000,0000,,Some are very narrow, some are wide,
Dialogue: 0,0:07:48.98,0:07:50.41,Default,,0000,0000,0000,,some are shaded at the edges.
Dialogue: 0,0:07:50.43,0:07:54.04,Default,,0000,0000,0000,,And this is actually how astronomers\Nhave studied objects in the heavens,
Dialogue: 0,0:07:54.06,0:07:55.55,Default,,0000,0000,0000,,literally, for over a century.
Dialogue: 0,0:07:55.58,0:07:58.00,Default,,0000,0000,0000,,So here, each different atom and molecule
Dialogue: 0,0:07:58.03,0:07:59.55,Default,,0000,0000,0000,,has a special set of lines,
Dialogue: 0,0:07:59.58,0:08:01.13,Default,,0000,0000,0000,,a fingerprint, if you will.
Dialogue: 0,0:08:01.16,0:08:03.89,Default,,0000,0000,0000,,And that's how we study\Nexoplanet atmospheres.
Dialogue: 0,0:08:03.92,0:08:06.28,Default,,0000,0000,0000,,And I'll just never forget\Nwhen I started working
Dialogue: 0,0:08:06.30,0:08:08.16,Default,,0000,0000,0000,,on exoplanet atmospheres 20 years ago,
Dialogue: 0,0:08:08.18,0:08:09.37,Default,,0000,0000,0000,,how many people told me,
Dialogue: 0,0:08:09.39,0:08:10.60,Default,,0000,0000,0000,,"This will never happen.
Dialogue: 0,0:08:10.62,0:08:13.41,Default,,0000,0000,0000,,We'll never be able to study them.\NWhy are you bothering?"
Dialogue: 0,0:08:13.44,0:08:17.11,Default,,0000,0000,0000,,And that's why I'm pleased to tell you\Nabout all the atmospheres studied now,
Dialogue: 0,0:08:17.14,0:08:18.98,Default,,0000,0000,0000,,and this is really a field of its own.
Dialogue: 0,0:08:19.01,0:08:21.53,Default,,0000,0000,0000,,So when it comes to\Nother planets, other Earths,
Dialogue: 0,0:08:21.56,0:08:23.63,Default,,0000,0000,0000,,in the future when we can observe them,
Dialogue: 0,0:08:23.66,0:08:25.72,Default,,0000,0000,0000,,what kind of gases\Nwould we be looking for?
Dialogue: 0,0:08:26.14,0:08:29.32,Default,,0000,0000,0000,,Well, you know, our own Earth\Nhas oxygen in the atmosphere
Dialogue: 0,0:08:29.34,0:08:30.80,Default,,0000,0000,0000,,to 20 percent by volume.
Dialogue: 0,0:08:31.44,0:08:32.71,Default,,0000,0000,0000,,That's a lot of oxygen.
Dialogue: 0,0:08:33.46,0:08:36.20,Default,,0000,0000,0000,,But without plants\Nand photosynthetic life,
Dialogue: 0,0:08:36.23,0:08:37.64,Default,,0000,0000,0000,,there would be no oxygen,
Dialogue: 0,0:08:37.66,0:08:39.50,Default,,0000,0000,0000,,virtually no oxygen in our atmosphere.
Dialogue: 0,0:08:40.12,0:08:42.04,Default,,0000,0000,0000,,So oxygen is here because of life.
Dialogue: 0,0:08:42.06,0:08:46.17,Default,,0000,0000,0000,,And our goal then is to look for gases\Nin other planet atmospheres,
Dialogue: 0,0:08:46.19,0:08:48.23,Default,,0000,0000,0000,,gases that don't belong,
Dialogue: 0,0:08:48.26,0:08:50.64,Default,,0000,0000,0000,,that we might be able\Nto attribute to life.
Dialogue: 0,0:08:50.66,0:08:52.74,Default,,0000,0000,0000,,But which molecules should we search for?
Dialogue: 0,0:08:52.77,0:08:55.43,Default,,0000,0000,0000,,I actually told you\Nhow diverse exoplanets are.
Dialogue: 0,0:08:55.45,0:08:57.45,Default,,0000,0000,0000,,We expect that to continue in the future
Dialogue: 0,0:08:57.48,0:08:58.78,Default,,0000,0000,0000,,when we find other Earths.
Dialogue: 0,0:08:58.80,0:09:01.37,Default,,0000,0000,0000,,And that's one of the main things\NI'm working on now,
Dialogue: 0,0:09:01.40,0:09:02.69,Default,,0000,0000,0000,,I have a theory about this.
Dialogue: 0,0:09:02.71,0:09:05.00,Default,,0000,0000,0000,,It reminds me that nearly every day,
Dialogue: 0,0:09:05.02,0:09:07.68,Default,,0000,0000,0000,,I receive an email or emails
Dialogue: 0,0:09:07.70,0:09:11.33,Default,,0000,0000,0000,,from someone with a crazy theory\Nabout physics of gravity
Dialogue: 0,0:09:11.35,0:09:13.18,Default,,0000,0000,0000,,or cosmology or some such.
Dialogue: 0,0:09:13.21,0:09:16.54,Default,,0000,0000,0000,,So, please don't email me\None of your crazy theories.
Dialogue: 0,0:09:16.56,0:09:17.78,Default,,0000,0000,0000,,(Laughter)
Dialogue: 0,0:09:17.80,0:09:19.98,Default,,0000,0000,0000,,Well, I had my own crazy theory.
Dialogue: 0,0:09:20.00,0:09:21.99,Default,,0000,0000,0000,,But, who does the MIT professor go to?
Dialogue: 0,0:09:22.70,0:09:26.91,Default,,0000,0000,0000,,Well, I emailed a Nobel Laureate\Nin Physiology or Medicine
Dialogue: 0,0:09:26.94,0:09:28.91,Default,,0000,0000,0000,,and he said, "Sure, come and talk to me."
Dialogue: 0,0:09:28.94,0:09:30.93,Default,,0000,0000,0000,,So I brought my two biochemistry friends
Dialogue: 0,0:09:30.96,0:09:33.31,Default,,0000,0000,0000,,and we went to talk to him\Nabout our crazy theory.
Dialogue: 0,0:09:33.33,0:09:36.78,Default,,0000,0000,0000,,And that theory was that life\Nproduces all small molecules,
Dialogue: 0,0:09:36.80,0:09:38.47,Default,,0000,0000,0000,,so many molecules.
Dialogue: 0,0:09:38.50,0:09:41.39,Default,,0000,0000,0000,,Like, everything I could think of,\Nbut not being a chemist.
Dialogue: 0,0:09:41.42,0:09:42.60,Default,,0000,0000,0000,,Think about it:
Dialogue: 0,0:09:42.62,0:09:44.65,Default,,0000,0000,0000,,carbon dioxide, carbon monoxide,
Dialogue: 0,0:09:44.68,0:09:46.54,Default,,0000,0000,0000,,molecular hydrogen, molecular nitrogen,
Dialogue: 0,0:09:46.56,0:09:47.93,Default,,0000,0000,0000,,methane, methyl chloride --
Dialogue: 0,0:09:47.95,0:09:49.11,Default,,0000,0000,0000,,so many gases.
Dialogue: 0,0:09:49.14,0:09:51.07,Default,,0000,0000,0000,,They also exist for other reasons,
Dialogue: 0,0:09:51.09,0:09:52.95,Default,,0000,0000,0000,,but just life even produces ozone.
Dialogue: 0,0:09:52.97,0:09:54.73,Default,,0000,0000,0000,,So we go to talk to him about this,
Dialogue: 0,0:09:54.75,0:09:56.89,Default,,0000,0000,0000,,and immediately, he shot down the theory.
Dialogue: 0,0:09:57.23,0:09:59.49,Default,,0000,0000,0000,,He found an example that didn't exist.
Dialogue: 0,0:09:59.95,0:10:01.73,Default,,0000,0000,0000,,So, we went back to the drawing board
Dialogue: 0,0:10:01.75,0:10:05.18,Default,,0000,0000,0000,,and we think we have found something\Nvery interesting in another field.
Dialogue: 0,0:10:05.20,0:10:06.62,Default,,0000,0000,0000,,But back to exoplanets,
Dialogue: 0,0:10:06.65,0:10:09.93,Default,,0000,0000,0000,,the point is that life produces\Nso many different types of gases,
Dialogue: 0,0:10:09.95,0:10:12.16,Default,,0000,0000,0000,,literally thousands of gases.
Dialogue: 0,0:10:12.19,0:10:14.86,Default,,0000,0000,0000,,And so what we're doing now\Nis just trying to figure out
Dialogue: 0,0:10:14.88,0:10:16.47,Default,,0000,0000,0000,,on which types of exoplanets,
Dialogue: 0,0:10:16.49,0:10:19.71,Default,,0000,0000,0000,,which gases could be attributed to life.
Dialogue: 0,0:10:22.18,0:10:24.23,Default,,0000,0000,0000,,And so when it comes time\Nwhen we find gases
Dialogue: 0,0:10:24.25,0:10:25.60,Default,,0000,0000,0000,,in exoplanet atmospheres
Dialogue: 0,0:10:25.63,0:10:27.72,Default,,0000,0000,0000,,that we won't know\Nif they're being produced
Dialogue: 0,0:10:27.75,0:10:30.78,Default,,0000,0000,0000,,by intelligent aliens or by trees,
Dialogue: 0,0:10:30.80,0:10:32.01,Default,,0000,0000,0000,,or a swamp,
Dialogue: 0,0:10:32.04,0:10:34.90,Default,,0000,0000,0000,,or even just by simple,\Nsingle-celled microbial life.
Dialogue: 0,0:10:35.54,0:10:37.09,Default,,0000,0000,0000,,So working on the models
Dialogue: 0,0:10:37.12,0:10:38.77,Default,,0000,0000,0000,,and thinking about biochemistry,
Dialogue: 0,0:10:38.79,0:10:39.99,Default,,0000,0000,0000,,it's all well and good.
Dialogue: 0,0:10:40.01,0:10:42.90,Default,,0000,0000,0000,,But a really big challenge\Nahead of us is: how?
Dialogue: 0,0:10:42.92,0:10:45.08,Default,,0000,0000,0000,,How are we going to find these planets?
Dialogue: 0,0:10:45.11,0:10:47.31,Default,,0000,0000,0000,,There are actually many ways\Nto find planets,
Dialogue: 0,0:10:47.31,0:10:48.83,Default,,0000,0000,0000,,several different ways.
Dialogue: 0,0:10:48.85,0:10:52.71,Default,,0000,0000,0000,,But the one that I'm most focused on\Nis how can we open a gateway
Dialogue: 0,0:10:52.74,0:10:53.97,Default,,0000,0000,0000,,so that in the future,
Dialogue: 0,0:10:53.100,0:10:55.85,Default,,0000,0000,0000,,we can find hundreds of Earths.
Dialogue: 0,0:10:55.87,0:10:58.20,Default,,0000,0000,0000,,We have a real shot\Nat finding signs of life.
Dialogue: 0,0:10:58.23,0:11:01.35,Default,,0000,0000,0000,,And actually, I just finished\Nleading a two-year project
Dialogue: 0,0:11:01.38,0:11:03.46,Default,,0000,0000,0000,,in this very special phase
Dialogue: 0,0:11:03.49,0:11:06.14,Default,,0000,0000,0000,,of a concept we call the starshade.
Dialogue: 0,0:11:06.17,0:11:09.12,Default,,0000,0000,0000,,And the starshade\Nis a very specially shaped screen
Dialogue: 0,0:11:09.14,0:11:11.01,Default,,0000,0000,0000,,and the goal is to fly that starshade
Dialogue: 0,0:11:11.04,0:11:14.13,Default,,0000,0000,0000,,so it blocks out the light of a star
Dialogue: 0,0:11:14.15,0:11:17.09,Default,,0000,0000,0000,,so that the telescope\Ncan see the planets directly.
Dialogue: 0,0:11:17.12,0:11:19.51,Default,,0000,0000,0000,,Here, you can see myself\Nand two team members
Dialogue: 0,0:11:19.53,0:11:21.72,Default,,0000,0000,0000,,holding up one small part\Nof the starshade.
Dialogue: 0,0:11:21.75,0:11:23.33,Default,,0000,0000,0000,,It's shaped like a giant flower,
Dialogue: 0,0:11:23.35,0:11:25.83,Default,,0000,0000,0000,,and this is one of the prototype petals.
Dialogue: 0,0:11:26.91,0:11:31.37,Default,,0000,0000,0000,,The concept is that a starshade\Nand telescope could launch together,
Dialogue: 0,0:11:31.39,0:11:33.99,Default,,0000,0000,0000,,with the petals unfurling\Nfrom the stowed position.
Dialogue: 0,0:11:34.90,0:11:36.95,Default,,0000,0000,0000,,The central truss would expand,
Dialogue: 0,0:11:36.98,0:11:40.07,Default,,0000,0000,0000,,with the petals snapping into place.
Dialogue: 0,0:11:40.09,0:11:42.32,Default,,0000,0000,0000,,Now, this has to be made very precisely,
Dialogue: 0,0:11:42.35,0:11:43.93,Default,,0000,0000,0000,,literally, the petals to microns
Dialogue: 0,0:11:43.96,0:11:46.67,Default,,0000,0000,0000,,and they have to deploy to millimeters.
Dialogue: 0,0:11:46.70,0:11:48.75,Default,,0000,0000,0000,,And this whole structure would have to fly
Dialogue: 0,0:11:48.78,0:11:52.14,Default,,0000,0000,0000,,tens of thousands of kilometers\Naway from the telescope.
Dialogue: 0,0:11:52.16,0:11:54.30,Default,,0000,0000,0000,,It's about tens of meters in diameter.
Dialogue: 0,0:11:54.78,0:11:59.74,Default,,0000,0000,0000,,And the goal is to block out\Nthe starlight to incredible precision
Dialogue: 0,0:11:59.76,0:12:02.50,Default,,0000,0000,0000,,so that we'd be able to see\Nthe planets directly.
Dialogue: 0,0:12:03.33,0:12:05.56,Default,,0000,0000,0000,,And it has to be a very special shape,
Dialogue: 0,0:12:05.59,0:12:07.48,Default,,0000,0000,0000,,because of the physics of defraction.
Dialogue: 0,0:12:07.50,0:12:09.72,Default,,0000,0000,0000,,Now this is a real project\Nthat we worked on,
Dialogue: 0,0:12:09.74,0:12:12.21,Default,,0000,0000,0000,,literally, you would not believe how hard.
Dialogue: 0,0:12:12.23,0:12:14.90,Default,,0000,0000,0000,,Just so you believe\Nit's not just in movie format,
Dialogue: 0,0:12:14.92,0:12:16.56,Default,,0000,0000,0000,,here's a real photograph
Dialogue: 0,0:12:16.58,0:12:21.57,Default,,0000,0000,0000,,of a second-generation\Nstarshade deployment test bed in the lab.
Dialogue: 0,0:12:21.60,0:12:23.67,Default,,0000,0000,0000,,And in this case,\NI just wanted you to know
Dialogue: 0,0:12:23.70,0:12:26.19,Default,,0000,0000,0000,,that that central truss\Nhas heritage left over
Dialogue: 0,0:12:26.21,0:12:28.13,Default,,0000,0000,0000,,from large radio deployables in space.
Dialogue: 0,0:12:29.37,0:12:31.03,Default,,0000,0000,0000,,So after all of that hard work
Dialogue: 0,0:12:31.05,0:12:34.84,Default,,0000,0000,0000,,where we try to think of all the crazy\Ngases that might be out there,
Dialogue: 0,0:12:34.87,0:12:37.80,Default,,0000,0000,0000,,and we build the very\Ncomplicated space telescopes
Dialogue: 0,0:12:37.82,0:12:39.05,Default,,0000,0000,0000,,that might be out there,
Dialogue: 0,0:12:39.07,0:12:40.37,Default,,0000,0000,0000,,what are we going to find?
Dialogue: 0,0:12:40.72,0:12:42.48,Default,,0000,0000,0000,,Well, in the best case,
Dialogue: 0,0:12:42.51,0:12:45.30,Default,,0000,0000,0000,,we will find an image\Nof another exo-Earth.
Dialogue: 0,0:12:46.33,0:12:48.59,Default,,0000,0000,0000,,Here is Earth as a pale blue dot.
Dialogue: 0,0:12:48.61,0:12:51.17,Default,,0000,0000,0000,,And this is actually\Na real photograph of Earth
Dialogue: 0,0:12:51.19,0:12:53.06,Default,,0000,0000,0000,,taken by the Voyager 1 spacecraft,
Dialogue: 0,0:12:53.09,0:12:54.71,Default,,0000,0000,0000,,four billion miles away.
Dialogue: 0,0:12:55.16,0:12:58.40,Default,,0000,0000,0000,,And that red light is just scattered light\Nin the camera optics.
Dialogue: 0,0:12:59.32,0:13:01.71,Default,,0000,0000,0000,,But what's so awesome to consider
Dialogue: 0,0:13:01.74,0:13:04.78,Default,,0000,0000,0000,,is that if there are intelligent aliens
Dialogue: 0,0:13:04.81,0:13:08.76,Default,,0000,0000,0000,,orbiting on a planet\Naround a star near to us
Dialogue: 0,0:13:08.79,0:13:10.83,Default,,0000,0000,0000,,and they build complicated\Nspace telescopes
Dialogue: 0,0:13:10.86,0:13:12.78,Default,,0000,0000,0000,,of the kind that we're trying to build,
Dialogue: 0,0:13:12.81,0:13:15.31,Default,,0000,0000,0000,,all they'll see is this pale blue dot,
Dialogue: 0,0:13:15.33,0:13:16.62,Default,,0000,0000,0000,,a pinprick of light.
Dialogue: 0,0:13:17.46,0:13:20.52,Default,,0000,0000,0000,,And so sometimes, when I pause to think
Dialogue: 0,0:13:20.55,0:13:24.80,Default,,0000,0000,0000,,about my professional struggle\Nand huge ambition,
Dialogue: 0,0:13:24.82,0:13:26.82,Default,,0000,0000,0000,,it's hard to think about that
Dialogue: 0,0:13:26.84,0:13:29.26,Default,,0000,0000,0000,,in contrast to the vastness\Nof the universe.
Dialogue: 0,0:13:30.12,0:13:34.25,Default,,0000,0000,0000,,But nonetheless, I am devoting\Nthe rest of my life
Dialogue: 0,0:13:34.27,0:13:35.62,Default,,0000,0000,0000,,to finding another Earth.
Dialogue: 0,0:13:36.30,0:13:38.51,Default,,0000,0000,0000,,And I can guarantee
Dialogue: 0,0:13:38.54,0:13:40.92,Default,,0000,0000,0000,,that in the next generation\Nof space telescopes,
Dialogue: 0,0:13:40.94,0:13:42.48,Default,,0000,0000,0000,,in the second generation,
Dialogue: 0,0:13:42.51,0:13:47.91,Default,,0000,0000,0000,,we will have the capability\Nto find and identity other Earths.
Dialogue: 0,0:13:47.94,0:13:50.61,Default,,0000,0000,0000,,And the capability\Nto split up the starlight
Dialogue: 0,0:13:50.63,0:13:52.19,Default,,0000,0000,0000,,so that we can look for gases
Dialogue: 0,0:13:52.21,0:13:55.70,Default,,0000,0000,0000,,and assess the greenhouse gases\Nin the atmosphere,
Dialogue: 0,0:13:55.72,0:13:57.32,Default,,0000,0000,0000,,estimate the surface temperature,
Dialogue: 0,0:13:57.34,0:13:59.10,Default,,0000,0000,0000,,and look for signs of life.
Dialogue: 0,0:13:59.74,0:14:01.16,Default,,0000,0000,0000,,But there's more.
Dialogue: 0,0:14:01.18,0:14:04.54,Default,,0000,0000,0000,,In this case of searching\Nfor other planets like Earth,
Dialogue: 0,0:14:04.57,0:14:07.16,Default,,0000,0000,0000,,we are making a new kind of map
Dialogue: 0,0:14:07.19,0:14:10.45,Default,,0000,0000,0000,,of the nearby stars\Nand of the planets orbiting them,
Dialogue: 0,0:14:10.47,0:14:14.24,Default,,0000,0000,0000,,including [planets] that actually might be\Ninhabitable by humans.
Dialogue: 0,0:14:14.92,0:14:17.30,Default,,0000,0000,0000,,And so I envision that our descendants,
Dialogue: 0,0:14:17.32,0:14:19.12,Default,,0000,0000,0000,,hundreds of years from now,
Dialogue: 0,0:14:19.15,0:14:22.18,Default,,0000,0000,0000,,will embark on an interstellar\Njourney to other worlds.
Dialogue: 0,0:14:23.06,0:14:25.97,Default,,0000,0000,0000,,And they will look back at all of us
Dialogue: 0,0:14:25.100,0:14:29.00,Default,,0000,0000,0000,,as the generation who first found\Nthe Earth-like worlds.
Dialogue: 0,0:14:29.82,0:14:30.97,Default,,0000,0000,0000,,Thank you.
Dialogue: 0,0:14:30.100,0:14:37.51,Default,,0000,0000,0000,,(Applause)
Dialogue: 0,0:14:37.53,0:14:39.63,Default,,0000,0000,0000,,June Cohen: And I give you,\Nfor a question,
Dialogue: 0,0:14:39.66,0:14:41.38,Default,,0000,0000,0000,,Rosetta Mission Manager Fred Jansen.
Dialogue: 0,0:14:41.82,0:14:43.85,Default,,0000,0000,0000,,Fred Jansen: You mentioned halfway through
Dialogue: 0,0:14:43.87,0:14:47.66,Default,,0000,0000,0000,,that the technology\Nto actually look at the spectrum
Dialogue: 0,0:14:47.68,0:14:50.31,Default,,0000,0000,0000,,of an exoplanet like Earth\Nis not there yet.
Dialogue: 0,0:14:50.34,0:14:52.22,Default,,0000,0000,0000,,When do you expect this will be there,
Dialogue: 0,0:14:52.25,0:14:53.52,Default,,0000,0000,0000,,and what's needed?
Dialogue: 0,0:14:53.54,0:14:58.15,Default,,0000,0000,0000,,Actually, what we expect is what we call\Nour next-generation Hubble telescope.
Dialogue: 0,0:14:58.53,0:15:00.87,Default,,0000,0000,0000,,And this is called the James Webb\NSpace Telescope,
Dialogue: 0,0:15:00.90,0:15:02.60,Default,,0000,0000,0000,,and that will launch in 2018,
Dialogue: 0,0:15:02.62,0:15:04.44,Default,,0000,0000,0000,,and that's what we're going to do,
Dialogue: 0,0:15:04.47,0:15:06.73,Default,,0000,0000,0000,,we're going to look\Nat a special kind of planet
Dialogue: 0,0:15:06.76,0:15:08.21,Default,,0000,0000,0000,,called transient exoplanets,
Dialogue: 0,0:15:08.24,0:15:11.34,Default,,0000,0000,0000,,and that will be our first shot\Nat studying small planets
Dialogue: 0,0:15:11.36,0:15:14.66,Default,,0000,0000,0000,,for gases that might indicate\Nthe planet is habitable.
Dialogue: 0,0:15:15.48,0:15:18.29,Default,,0000,0000,0000,,JC: I'm going to ask you\None follow-up question, too, Sara,
Dialogue: 0,0:15:18.31,0:15:19.52,Default,,0000,0000,0000,,as the generalist.
Dialogue: 0,0:15:19.54,0:15:22.63,Default,,0000,0000,0000,,So I am really struck\Nby the notion in your career
Dialogue: 0,0:15:22.66,0:15:24.06,Default,,0000,0000,0000,,of the opposition you faced,
Dialogue: 0,0:15:24.08,0:15:26.22,Default,,0000,0000,0000,,that when you began thinking\Nabout exoplanets,
Dialogue: 0,0:15:26.25,0:15:28.91,Default,,0000,0000,0000,,there was extreme skepticism\Nin the scientific community
Dialogue: 0,0:15:28.94,0:15:30.09,Default,,0000,0000,0000,,that they existed,
Dialogue: 0,0:15:30.11,0:15:31.38,Default,,0000,0000,0000,,and you proved them wrong.
Dialogue: 0,0:15:31.41,0:15:33.12,Default,,0000,0000,0000,,What did it take to take that on?
Dialogue: 0,0:15:33.14,0:15:35.21,Default,,0000,0000,0000,,SS: Well, the thing is that as scientists,
Dialogue: 0,0:15:35.24,0:15:37.20,Default,,0000,0000,0000,,we're supposed to be skeptical,
Dialogue: 0,0:15:37.22,0:15:40.27,Default,,0000,0000,0000,,because our job to make sure\Nthat what the other person is saying
Dialogue: 0,0:15:40.29,0:15:41.63,Default,,0000,0000,0000,,actually makes sense or not.
Dialogue: 0,0:15:41.65,0:15:44.21,Default,,0000,0000,0000,,But being a scientist,
Dialogue: 0,0:15:44.24,0:15:46.66,Default,,0000,0000,0000,,I think you've seen it from this session,
Dialogue: 0,0:15:46.68,0:15:48.36,Default,,0000,0000,0000,,it's like being an explorer.
Dialogue: 0,0:15:48.38,0:15:50.37,Default,,0000,0000,0000,,You have this immense curiosity,
Dialogue: 0,0:15:50.40,0:15:51.70,Default,,0000,0000,0000,,this stubbornness,
Dialogue: 0,0:15:51.72,0:15:54.10,Default,,0000,0000,0000,,this sort of resolute will\Nthat you will go forward
Dialogue: 0,0:15:54.13,0:15:56.16,Default,,0000,0000,0000,,no matter what other people say.
Dialogue: 0,0:15:56.18,0:15:57.86,Default,,0000,0000,0000,,JC: I love that. Thank you, Sara.
Dialogue: 0,0:15:57.88,0:16:00.88,Default,,0000,0000,0000,,(Applause)