WEBVTT NOTE This file was generated by Descript 00:00:01.770 --> 00:00:05.640 When I see the stars, I think about how all of them are suns and how if 00:00:05.640 --> 00:00:09.270 our sun has planets, it makes sense that those other stars have planets. 00:00:09.270 --> 00:00:13.770 Also, our galaxy alone with its hundreds of billions of stars, 00:00:13.830 --> 00:00:15.720 probably has over a trillion planets. 00:00:15.720 --> 00:00:18.270 I. Numbers so vast we can barely comprehend them. 00:00:20.820 --> 00:00:25.530 I am Professor Sarah Seager at the Massachusetts Institute of Technology. 00:00:26.189 --> 00:00:28.710 I'm thrilled to be one of this year's winners of the 00:00:28.710 --> 00:00:30.840 Kavli Prize in astrophysics. 00:00:31.830 --> 00:00:36.945 I. The large amount of work in exoplanets today is based on the foundation 00:00:36.945 --> 00:00:38.685 that I and my co-winner sat down. 00:00:39.525 --> 00:00:42.915 My co-recipient, Dave Charbonneau, ended up getting the candidate and 00:00:42.915 --> 00:00:47.385 finding the first transit in exoplanet, but that enabled me to rush to finish 00:00:47.385 --> 00:00:50.805 my paper, I had already started on transit transmission spectroscopy. 00:00:51.315 --> 00:00:53.835 I'm so proud to have invented the main way. 00:00:53.835 --> 00:00:57.614 We study exoplanet atmospheres today, transit transmission spectroscopy. 00:00:59.190 --> 00:01:02.460 When the planet goes in front of the star, the starlight drops by a very 00:01:02.460 --> 00:01:06.060 characteristic amount related to the planet area, to the star area. 00:01:06.780 --> 00:01:10.470 Now, if the planet has an atmosphere, the starlight drops by the area 00:01:10.470 --> 00:01:13.140 of the planet, plus the area of the ring caused by the atmosphere. 00:01:14.445 --> 00:01:18.884 So if we imagine measuring the planet at a wavelength where the atmosphere is 00:01:18.884 --> 00:01:21.134 fully transparent, we get a certain size. 00:01:22.125 --> 00:01:24.735 Now, if we measure an adjacent wavelength where the atmosphere 00:01:24.735 --> 00:01:27.735 is strongly absorbing, the planet looks a tiny bit bigger, and that's 00:01:27.735 --> 00:01:29.265 how we study exoplanet atmospheres 00:01:31.545 --> 00:01:33.735 in the search for signs of life on exoplanets. 00:01:33.824 --> 00:01:38.475 We're just simply looking for a gas that's way out of equilibrium in context with 00:01:38.475 --> 00:01:42.975 this environment like oxygen here on earth, we still have a long way to go. 00:01:43.765 --> 00:01:46.795 In the near term, it's just sorting through what exoplanets actually are 00:01:46.915 --> 00:01:50.155 using the transmission spectroscopy method with the James Webb Space Telescope. 00:01:51.055 --> 00:01:53.395 Longer term, I'm in love with Venus. 00:01:53.785 --> 00:01:56.425 Venus is kind of like our evil twin sister. 00:01:57.175 --> 00:01:59.635 It has a massive greenhouse atmosphere, making the surface 00:01:59.635 --> 00:02:01.015 too hot for life of any kind. 00:02:02.010 --> 00:02:06.390 However, we're starting to think that maybe Carl Sagan's idea from half a 00:02:06.390 --> 00:02:09.840 century ago that there might be life on Venus in the Clouds, where it's much 00:02:09.840 --> 00:02:11.670 cooler could actually be realistic. 00:02:12.210 --> 00:02:17.620 So that is my main focus right now in my heart and what I've dedicated the 00:02:17.674 --> 00:02:22.114 rest of my life to is finding a true earth twin, a planet that's about earth 00:02:22.114 --> 00:02:26.315 size, about earth's mass orbiting a sunlike star in an earthlike orbit, 00:02:26.765 --> 00:02:31.535 and the transit transmission spectra probably can't be used because the earth 00:02:31.535 --> 00:02:34.774 atmosphere compared to the backdrop of a Sunlike star is just too tiny. 00:02:35.105 --> 00:02:37.954 Instead, we'll need a special sophisticated space telescope. 00:02:38.554 --> 00:02:41.135 The telescope will be what we call star shade. 00:02:41.135 --> 00:02:41.435 Ready. 00:02:41.825 --> 00:02:44.644 A star shade looks like a huge flower with petals. 00:02:44.695 --> 00:02:47.035 Star shade will block out the starlight. 00:02:47.215 --> 00:02:49.375 So only planet light enters the telescope. 00:02:50.185 --> 00:02:54.385 It has such huge, wonderful capability to study the 00:02:54.385 --> 00:02:56.575 atmospheres of Earth-like worlds. 00:02:58.195 --> 00:03:03.265 As humans, we desire to understand what else is out there in that vast. 00:03:03.310 --> 00:03:07.690 Night sky and because of today's tools, we're able to reframe that question 00:03:07.750 --> 00:03:12.070 as, are there other earths, do they have signs of life and can we identify 00:03:12.070 --> 00:03:13.810 any habitable or inhabited worlds?