1 00:00:01,466 --> 00:00:03,266 - Sarah Corso: Hello, everyone. 2 00:00:03,266 --> 00:00:06,600 Welcome, and thank you for coming to tonight's Badger Talk, 3 00:00:06,600 --> 00:00:09,000 brought to you by UW Connects. 4 00:00:09,000 --> 00:00:10,700 My name is Sarah Corso, 5 00:00:10,700 --> 00:00:12,966 and I'm a librarian and access services manager 6 00:00:12,966 --> 00:00:15,766 here at the Oak Creek Public Library. 7 00:00:15,766 --> 00:00:17,900 I'm pleased to introduce our guest, 8 00:00:17,900 --> 00:00:19,566 Dr. Thomas Beatty, 9 00:00:19,566 --> 00:00:21,900 assistant professor in the Astronomy Department 10 00:00:21,900 --> 00:00:24,300 for the College of Letters & Science 11 00:00:24,300 --> 00:00:27,200 at the University of Wisconsin-Madison. 12 00:00:27,200 --> 00:00:30,233 The presentation he is giving this evening is called 13 00:00:30,233 --> 00:00:33,733 "How Can We Find Other Life in the Universe?" 14 00:00:33,733 --> 00:00:36,166 Dr. Beatty is from Riverside, Connecticut, 15 00:00:36,166 --> 00:00:39,033 and grew up sailing off the coast of New England. 16 00:00:39,033 --> 00:00:41,900 He has a bachelor's degree from Harvard University, 17 00:00:41,900 --> 00:00:44,966 a master's degree in physics from MIT, 18 00:00:44,966 --> 00:00:49,333 and a PhD in astronomy from Ohio State University. 19 00:00:49,333 --> 00:00:51,666 Before moving to Madison, 20 00:00:51,666 --> 00:00:53,833 he worked as an instrument scientist 21 00:00:53,833 --> 00:00:56,266 on the James Webb Space Telescope, 22 00:00:56,266 --> 00:00:58,800 where he helped build one of Webb's cameras 23 00:00:58,800 --> 00:01:02,566 and helped to operate it once Webb reached space. 24 00:01:02,566 --> 00:01:05,533 His research focuses on measuring the atmospheres 25 00:01:05,533 --> 00:01:09,133 of exoplanets-- planets around other stars-- 26 00:01:09,133 --> 00:01:11,500 to figure out what they are made out of 27 00:01:11,500 --> 00:01:15,100 and what their climates are like to understand how planets form 28 00:01:15,100 --> 00:01:18,900 and to search for life elsewhere in the universe. 29 00:01:18,900 --> 00:01:22,366 He has also discovered nine new exoplanets, 30 00:01:22,366 --> 00:01:26,633 none of which he got to name after himself, sadly. 31 00:01:26,633 --> 00:01:30,200 Today, we are asking, "Are we alone in the universe?" 32 00:01:30,200 --> 00:01:34,100 This question has been asked for over 2,000 years, 33 00:01:34,100 --> 00:01:37,333 and now we possess the tools and techniques necessary 34 00:01:37,333 --> 00:01:39,233 to answer it. 35 00:01:39,233 --> 00:01:42,200 Dr. Beatty will discuss what we want to look for 36 00:01:42,200 --> 00:01:45,433 on other planets to see if there is life, 37 00:01:45,433 --> 00:01:48,533 as well as how this search has begun at UW 38 00:01:48,533 --> 00:01:51,400 using current and future telescopes. 39 00:01:51,400 --> 00:01:54,000 Please join me in welcoming Dr. Beatty. 40 00:01:54,000 --> 00:01:56,666 [audience applauding] 41 00:02:00,066 --> 00:02:01,733 - Thomas G. Beatty: Thank you very much. 42 00:02:01,733 --> 00:02:03,166 That was a very nice introduction. 43 00:02:03,166 --> 00:02:04,500 It's a pleasure to be here. 44 00:02:04,500 --> 00:02:06,733 I actually, coincidentally, am in the universe. 45 00:02:06,733 --> 00:02:09,433 And, really, how can we find life elsewhere, 46 00:02:09,433 --> 00:02:13,166 and how are we trying to approach this problem 47 00:02:13,166 --> 00:02:16,466 at UW and, in general, in the astronomical community 48 00:02:16,466 --> 00:02:19,300 to try and solve this question? 49 00:02:19,300 --> 00:02:22,200 And I like to begin talks like this 50 00:02:22,200 --> 00:02:24,433 with just sort of a picture of the night sky 51 00:02:24,433 --> 00:02:27,700 and the thought, the idea, that in many ways, 52 00:02:27,700 --> 00:02:31,133 astronomy is sort of, you know, the second-oldest profession 53 00:02:31,133 --> 00:02:33,133 in the world-- being an astronomer, right? 54 00:02:33,133 --> 00:02:35,433 It's probably the oldest science that we have 55 00:02:35,433 --> 00:02:38,433 in the sense of you could imagine people, 56 00:02:38,433 --> 00:02:41,666 very early people in Africa, just looking up at the night sky 57 00:02:41,666 --> 00:02:44,033 and wondering what is going on up there, 58 00:02:44,033 --> 00:02:45,800 what's going on with the stars, 59 00:02:45,800 --> 00:02:49,033 and that, fundamentally, is what my job is. 60 00:02:49,033 --> 00:02:50,633 What we do as astronomers today is, 61 00:02:50,633 --> 00:02:52,333 we're still looking up at the night sky, 62 00:02:52,333 --> 00:02:54,066 and we're still trying to figure out 63 00:02:54,066 --> 00:02:56,833 what's going on with the stars. 64 00:02:56,833 --> 00:02:59,833 And, in particular, I work on exoplanets, 65 00:02:59,833 --> 00:03:01,566 so I look for planets around other stars, 66 00:03:01,566 --> 00:03:03,600 and we're trying to measure these planets around other stars 67 00:03:03,600 --> 00:03:06,400 and figure out if there's planets like the Earth 68 00:03:06,400 --> 00:03:08,266 elsewhere in the galaxy. 69 00:03:08,266 --> 00:03:11,900 That question, the idea that there might be another planet 70 00:03:11,900 --> 00:03:14,900 like the Earth somewhere up there, 71 00:03:14,900 --> 00:03:17,366 probably-- it's a little bit fuzzy-- 72 00:03:17,366 --> 00:03:19,866 was probably first posed by the ancient Greeks 73 00:03:19,866 --> 00:03:22,466 about 2,500 years ago, probably the first person 74 00:03:22,466 --> 00:03:24,500 to, at least, write that question down. 75 00:03:24,500 --> 00:03:27,900 Maybe people thought of it before that. 76 00:03:27,900 --> 00:03:32,566 So we're really thinking today very concretely 77 00:03:32,566 --> 00:03:34,233 about how do we answer this question: 78 00:03:34,233 --> 00:03:35,633 Is there a planet like the Earth 79 00:03:35,633 --> 00:03:37,100 somewhere else in the universe? 80 00:03:37,100 --> 00:03:39,100 And it's a question that people have been wondering about 81 00:03:39,100 --> 00:03:42,100 for over two millennia, 82 00:03:42,100 --> 00:03:44,266 and we're very close to actually answering it, 83 00:03:44,266 --> 00:03:45,700 and that's the topic 84 00:03:45,700 --> 00:03:48,533 of what I'd like to talk to you about tonight. 85 00:03:48,533 --> 00:03:50,666 So I wanna begin by just talking 86 00:03:50,666 --> 00:03:53,200 about what is an exoplanet, right? 87 00:03:53,200 --> 00:03:55,600 What does that mean when I talk about an exoplanet? 88 00:03:55,600 --> 00:03:57,433 What are those? 89 00:03:58,533 --> 00:04:01,100 So in the solar system, 90 00:04:01,100 --> 00:04:03,400 we have our planets in our solar system. 91 00:04:03,400 --> 00:04:05,633 We have all the planets that go around the Sun, 92 00:04:05,633 --> 00:04:07,300 so the planets go around the Sun, 93 00:04:07,300 --> 00:04:08,800 those are planets, 94 00:04:08,800 --> 00:04:12,133 and an exoplanet is simply a planet 95 00:04:12,133 --> 00:04:15,100 that orbits a star other than the Sun. 96 00:04:15,100 --> 00:04:16,266 So just like the Sun 97 00:04:16,266 --> 00:04:18,000 has a solar system of planets around it, 98 00:04:18,000 --> 00:04:21,033 there are other exoplanet systems around other stars 99 00:04:21,033 --> 00:04:23,933 elsewhere in our galaxy that we know of. 100 00:04:25,700 --> 00:04:30,066 In galactic terms, 101 00:04:30,066 --> 00:04:32,566 most of the planets that we are looking at 102 00:04:32,566 --> 00:04:36,100 are very close by in the terms of the universe, right? 103 00:04:36,100 --> 00:04:39,833 All the planets that we know of are within the Milky Way galaxy. 104 00:04:39,833 --> 00:04:44,466 This is a nice map produced by Professor Bob Benjamin, 105 00:04:44,466 --> 00:04:46,633 who's at UW, right, 106 00:04:46,633 --> 00:04:48,100 showing what the Milky Way looks like, 107 00:04:48,100 --> 00:04:50,100 so all the planets that we're thinking about looking at 108 00:04:50,100 --> 00:04:53,833 and know about are within the Milky Way galaxy, 109 00:04:53,833 --> 00:04:56,333 and they're actually very close to the sun, 110 00:04:56,333 --> 00:04:58,100 within the Milky Way galaxy, right? 111 00:04:58,100 --> 00:05:01,100 This red circle is about the limit of detection, 112 00:05:01,100 --> 00:05:04,233 so where we've seen exoplanets, how far out we've seen them. 113 00:05:04,233 --> 00:05:06,833 If I zoom back out on the entire galaxy, 114 00:05:06,833 --> 00:05:09,933 you can see we've actually been probing a very small segment 115 00:05:09,933 --> 00:05:12,733 just of our local corner of the universe, right? 116 00:05:12,733 --> 00:05:14,433 We now know of a lot of exoplanets, 117 00:05:14,433 --> 00:05:16,433 but all of them are very close by 118 00:05:16,433 --> 00:05:18,300 on an astronomical scale. 119 00:05:18,300 --> 00:05:19,500 They're all within our galaxy, 120 00:05:19,500 --> 00:05:21,333 and they're all close within our galaxy. 121 00:05:22,866 --> 00:05:26,266 All together, over the last 25 years-- 122 00:05:26,266 --> 00:05:27,933 30 years now, 123 00:05:27,933 --> 00:05:31,300 we've now discovered over 5,000 exoplanets. 124 00:05:31,300 --> 00:05:36,366 I think the count as of this morning was 5,761, right? 125 00:05:36,366 --> 00:05:40,266 And if you look at this graph, right, 126 00:05:40,266 --> 00:05:42,933 you can see there's actually a lot of sort of features here 127 00:05:42,933 --> 00:05:44,500 you could think about teasing out. 128 00:05:44,500 --> 00:05:47,666 So I've marked on this slide, 129 00:05:47,666 --> 00:05:49,466 the capital J is where Jupiter is, 130 00:05:49,466 --> 00:05:52,133 and the capital E is where the Earth is, 131 00:05:52,133 --> 00:05:53,733 and you can see we have 132 00:05:53,733 --> 00:05:55,766 a whole bunch of planets that are like Jupiter, 133 00:05:55,766 --> 00:05:57,966 we have a whole bunch of planets that are like Earth, 134 00:05:57,966 --> 00:05:59,566 and a whole bunch of things in between, 135 00:05:59,566 --> 00:06:01,833 and, in particular, we also have a whole bunch of planets 136 00:06:01,833 --> 00:06:04,500 that don't even really exist in our solar system, right? 137 00:06:04,500 --> 00:06:07,066 A lot of the ways that even we astronomers conceptualize 138 00:06:07,066 --> 00:06:09,633 what these planets look like is by thinking about 139 00:06:09,633 --> 00:06:12,800 how do they compare to a planet in the solar system. 140 00:06:12,800 --> 00:06:14,566 Are they, like, a hot Jupiter? 141 00:06:14,566 --> 00:06:16,566 Are they a super-Earth? 142 00:06:16,566 --> 00:06:17,966 Are they a warm Saturn? 143 00:06:17,966 --> 00:06:19,133 We use words like that, 144 00:06:19,133 --> 00:06:21,633 but there is a whole class of planets, 145 00:06:21,633 --> 00:06:23,333 like super-Earths or sub-Neptunes, 146 00:06:23,333 --> 00:06:25,333 that don't actually exist in the solar system. 147 00:06:25,333 --> 00:06:27,533 And so, by finding all these new planets, 148 00:06:27,533 --> 00:06:30,266 we're actually uncovering new processes 149 00:06:30,266 --> 00:06:32,433 and physics that we didn't know about 150 00:06:32,433 --> 00:06:35,266 before we knew that these planets existed. 151 00:06:35,266 --> 00:06:39,800 And this has been a lot of the work of the last 30 years 152 00:06:39,800 --> 00:06:42,366 in this field, is finding new planets, 153 00:06:42,366 --> 00:06:44,266 getting this number to go from one-- 154 00:06:44,266 --> 00:06:46,533 the first one was discovered in 1995-- 155 00:06:46,533 --> 00:06:50,633 getting it from 1 to 5,761, right? 156 00:06:50,633 --> 00:06:53,600 That's taken a lot of work, and it's taken over two decades 157 00:06:53,600 --> 00:06:57,600 of people finding new planets around other stars. 158 00:06:58,800 --> 00:07:02,366 Most of these are discovered indirectly, right? 159 00:07:02,366 --> 00:07:05,566 We actually-- of those over 5,000 exoplanets, 160 00:07:05,566 --> 00:07:09,966 we only have direct images where we can see them in a photograph 161 00:07:09,966 --> 00:07:14,433 or an image for only a handful, probably about a dozen. 162 00:07:14,433 --> 00:07:17,300 Most of these, we never actually see the planet directly. 163 00:07:17,300 --> 00:07:19,900 Instead, what we see is, we see the planet's effect 164 00:07:19,900 --> 00:07:22,566 on the star that it's orbiting, right? 165 00:07:22,566 --> 00:07:26,933 So one way, on the left there, one way that we see the planet 166 00:07:26,933 --> 00:07:29,833 affecting its star is that we can look at the star, 167 00:07:29,833 --> 00:07:32,666 we can measure the velocity of the star, 168 00:07:32,666 --> 00:07:35,566 and we see the star moving back and forth a little bit 169 00:07:35,566 --> 00:07:39,233 because the planet as it orbits the star is tugging on the star, 170 00:07:39,233 --> 00:07:42,200 and the star itself is moving just a little bit 171 00:07:42,200 --> 00:07:44,233 as the planet orbits around it, 172 00:07:44,233 --> 00:07:46,433 and so we can see that motion of the star 173 00:07:46,433 --> 00:07:48,700 with our telescopes, right, so we see the star moving, 174 00:07:48,700 --> 00:07:51,100 and we know it must be a planet based on that motion. 175 00:07:51,100 --> 00:07:53,400 We never actually see the planet itself. 176 00:07:53,400 --> 00:07:56,233 Another way we discover planets, that's on the right, 177 00:07:56,233 --> 00:08:00,033 is, we look, and as a planet goes in front of a star, 178 00:08:00,033 --> 00:08:02,033 it will block out part of that star, 179 00:08:02,033 --> 00:08:03,833 and the light from the star will go down. 180 00:08:03,833 --> 00:08:06,533 So Jupiter going in front of the Sun 181 00:08:06,533 --> 00:08:08,800 would make the Sun get dimmer 182 00:08:08,800 --> 00:08:11,666 by about 1% for a couple of hours, 183 00:08:11,666 --> 00:08:13,833 and then it would go back up again, right? 184 00:08:13,833 --> 00:08:15,566 And we can detect planets that way. 185 00:08:15,566 --> 00:08:18,300 Actually, that technique has gotten-- 186 00:08:18,300 --> 00:08:20,500 We're all sufficiently good at doing that 187 00:08:20,500 --> 00:08:25,233 that I'm actually with a couple of students looking, 188 00:08:25,233 --> 00:08:28,066 trying to detect a new planet-- or confirm a new planet 189 00:08:28,066 --> 00:08:29,633 from the roof of the Astronomy Department 190 00:08:29,633 --> 00:08:33,566 in downtown Madison sometime next week. 191 00:08:33,566 --> 00:08:36,033 So that sort of measurement for a Jupiter 192 00:08:36,033 --> 00:08:38,533 in front of a Sun-like star has gotten relatively easy 193 00:08:38,533 --> 00:08:40,433 with modern technology. 194 00:08:40,433 --> 00:08:42,633 Planets like the Earth is a lot harder, right? 195 00:08:42,633 --> 00:08:46,333 The Earth is 10,000 times less of a signal 196 00:08:46,333 --> 00:08:48,500 that we have to measure, right, 197 00:08:48,500 --> 00:08:53,266 but the real point to just take away from this is, 198 00:08:53,266 --> 00:08:55,066 we have a lot of ways to detect planets. 199 00:08:55,066 --> 00:08:56,866 We've found a lot, and we know a lot 200 00:08:56,866 --> 00:08:59,666 from just their masses and their radii and their sizes 201 00:08:59,666 --> 00:09:02,033 and where they are relative to their stars, 202 00:09:02,033 --> 00:09:05,033 but we still never actually see the planet directly, right? 203 00:09:05,033 --> 00:09:06,833 We just see what it does to the star. 204 00:09:06,833 --> 00:09:09,666 We don't have a lot of information 205 00:09:09,666 --> 00:09:12,666 about what is happening on the planet itself. 206 00:09:12,666 --> 00:09:16,100 And so if we're thinking about detecting life on an exoplanet, 207 00:09:16,100 --> 00:09:19,433 figuring out if it's habitable, if it's like the Earth, right, 208 00:09:19,433 --> 00:09:21,900 what we will start with is something like this. 209 00:09:21,900 --> 00:09:24,600 This is a simulated light curve, 210 00:09:24,600 --> 00:09:26,600 so measurements of the brightness of a star, 211 00:09:26,600 --> 00:09:28,933 as a planet like the Earth goes in front of it. 212 00:09:28,933 --> 00:09:30,533 So if we were looking at the Sun 213 00:09:30,533 --> 00:09:32,133 and the Earth passed in front of it, 214 00:09:32,133 --> 00:09:33,333 this is what we would see. 215 00:09:33,333 --> 00:09:34,733 It's a very small signal. 216 00:09:34,733 --> 00:09:36,600 We'd have to measure it from space. 217 00:09:36,600 --> 00:09:39,000 And what we learn if we were looking at the Sun is, 218 00:09:39,000 --> 00:09:40,600 we could, you know, learn that the planet 219 00:09:40,600 --> 00:09:42,000 was about the size of the Earth. 220 00:09:42,000 --> 00:09:43,233 We maybe could get a mass 221 00:09:43,233 --> 00:09:44,833 by looking at the motion of the Sun, 222 00:09:44,833 --> 00:09:47,433 so we knew it was the mass and the radius of the Earth, 223 00:09:47,433 --> 00:09:50,033 and we know how far away it is 224 00:09:50,033 --> 00:09:52,966 using things like Kepler's laws and the orbital period. 225 00:09:52,966 --> 00:09:54,566 But the important thing is, 226 00:09:54,566 --> 00:09:56,800 if we were doing this on the solar system, 227 00:09:56,800 --> 00:09:58,666 we wouldn't just get one planet like the Earth. 228 00:09:58,666 --> 00:10:00,666 We'd get two, right? 229 00:10:00,666 --> 00:10:02,266 If we were looking at the solar system 230 00:10:02,266 --> 00:10:05,466 with our current technology, 231 00:10:05,466 --> 00:10:08,100 we would say the solar system has two habitable planets 232 00:10:08,100 --> 00:10:10,500 because we have the Earth and we also have Venus, 233 00:10:10,500 --> 00:10:13,333 and Venus is nearly the same mass and radius as the Earth, 234 00:10:13,333 --> 00:10:17,233 and it's closer to the Sun, but it's not that much closer, 235 00:10:17,233 --> 00:10:19,600 and the theory we have about habitability 236 00:10:19,600 --> 00:10:22,533 says that Venus probably should be habitable. 237 00:10:22,533 --> 00:10:24,133 There's a lot of other factors, of course, 238 00:10:24,133 --> 00:10:25,766 that have made Venus not habitable, 239 00:10:25,766 --> 00:10:28,033 but we don't fully understand them yet, right? 240 00:10:28,033 --> 00:10:29,966 So one of the tasks that we have, 241 00:10:29,966 --> 00:10:33,133 and this is what I do, is trying to figure out, right, 242 00:10:33,133 --> 00:10:37,200 if we have a planet like this, how do we determine 243 00:10:37,200 --> 00:10:40,866 if it's like the Earth-- that is, a nice beach vacation-- 244 00:10:40,866 --> 00:10:45,500 or if it's like Venus and it's gonna melt your spacecraft 245 00:10:45,500 --> 00:10:47,966 30 minutes after you land, right? 246 00:10:47,966 --> 00:10:49,266 This is actually true. 247 00:10:49,266 --> 00:10:51,266 The only landers that we have that have ever reached 248 00:10:51,266 --> 00:10:54,333 the surface of Venus are a couple of Soviet landers 249 00:10:54,333 --> 00:10:56,166 that landed in the 1980s, 250 00:10:56,166 --> 00:10:57,700 and they only lasted on the surface 251 00:10:57,700 --> 00:11:01,000 for about 30 minutes before they got squished 252 00:11:01,000 --> 00:11:03,766 by some combination of crushed by the pressure 253 00:11:03,766 --> 00:11:05,766 and dissolved by the sulfuric acid 254 00:11:05,766 --> 00:11:08,633 that's present in Venus's atmosphere. 255 00:11:08,633 --> 00:11:10,866 And actually, a really fun story is, 256 00:11:10,866 --> 00:11:12,466 we don't actually have a very good measurement. 257 00:11:12,466 --> 00:11:14,266 This isn't that funny, this isn't that fun a-- 258 00:11:14,266 --> 00:11:15,466 It's a fun story for us. 259 00:11:15,466 --> 00:11:18,600 It's not a fun story for the scientists involved. 260 00:11:18,600 --> 00:11:20,333 So we don't really have a good measurement 261 00:11:20,333 --> 00:11:22,266 of the surface of Venus, 262 00:11:22,266 --> 00:11:25,466 like, what the, like, dirt is in that picture, 263 00:11:25,466 --> 00:11:28,400 because one of the-- 264 00:11:28,400 --> 00:11:30,633 So the first Soviet lander that landed on Venus, 265 00:11:30,633 --> 00:11:33,400 that had a camera, but the lens cap didn't come off, 266 00:11:33,400 --> 00:11:35,966 so they didn't get any pictures, and so they said, 267 00:11:35,966 --> 00:11:38,500 "Okay, for the next one, we're definitely making sure 268 00:11:38,500 --> 00:11:40,833 the lens cap is coming off," right, and it did. 269 00:11:40,833 --> 00:11:42,533 This is where this picture comes from, right, 270 00:11:42,533 --> 00:11:45,500 so the lens cap comes off as it's drifting down, 271 00:11:45,500 --> 00:11:47,433 and we get these nice pictures. 272 00:11:47,433 --> 00:11:49,233 But one of the next experiments they had-- 273 00:11:49,233 --> 00:11:51,233 and, remember, they only have about 30 minutes, and then 274 00:11:51,233 --> 00:11:54,733 the whole thing is done because the spacecraft has melted. 275 00:11:54,733 --> 00:11:56,733 One of the experiments they were gonna do was, 276 00:11:56,733 --> 00:11:59,666 there was a spring-loaded arm inside the spacecraft 277 00:11:59,666 --> 00:12:01,933 that was gonna, you know, a catch-release. 278 00:12:01,933 --> 00:12:04,866 As the spring shoots the arm out, it goes into the dirt, 279 00:12:04,866 --> 00:12:07,266 and then they retract it back, and they can get some dirt, 280 00:12:07,266 --> 00:12:10,966 and they can analyze it, but it's a one-shot thing. 281 00:12:10,966 --> 00:12:13,166 You can't retract the spring, 282 00:12:13,166 --> 00:12:15,066 you know, once it's fired, right? 283 00:12:15,066 --> 00:12:17,033 You fire it, you're done. 284 00:12:17,033 --> 00:12:19,200 And so they're down, they're all ready, 285 00:12:19,200 --> 00:12:20,366 they've released the spring. 286 00:12:20,366 --> 00:12:21,866 The arm shoots out, and it shoots 287 00:12:21,866 --> 00:12:25,266 directly into the lens cap that, 288 00:12:25,266 --> 00:12:27,966 even though it popped off about 500 feet up in the air, 289 00:12:27,966 --> 00:12:30,100 has landed directly next to the spacecraft 290 00:12:30,100 --> 00:12:33,333 and directly where this arm was about to shoot out into, 291 00:12:33,333 --> 00:12:35,766 and so that is why we don't actually have 292 00:12:35,766 --> 00:12:40,700 a good measurement of what Venus's surface is like. 293 00:12:40,700 --> 00:12:43,000 But okay, so we can't do that with exoplanets, right? 294 00:12:43,000 --> 00:12:44,166 We can't go there. 295 00:12:44,166 --> 00:12:46,900 We can't try and dodge lens cap covers 296 00:12:46,900 --> 00:12:48,433 to measure what these planets are like. 297 00:12:48,433 --> 00:12:51,200 We can't even see them most of the time, right, 298 00:12:51,200 --> 00:12:53,066 so we need to come up with other ways 299 00:12:53,066 --> 00:12:55,600 of figuring out what they're like. 300 00:12:55,600 --> 00:12:57,800 And so the main way in which we do this is, 301 00:12:57,800 --> 00:13:00,000 we look at their atmospheres by watching 302 00:13:00,000 --> 00:13:02,366 as transiting exoplanets-- 303 00:13:02,366 --> 00:13:05,466 Those are the exoplanets that pass in front of their stars. 304 00:13:05,466 --> 00:13:07,466 As they pass in front of their star, 305 00:13:07,466 --> 00:13:08,900 some of that light, 306 00:13:08,900 --> 00:13:10,900 some of that starlight that's getting blocked by the planet, 307 00:13:10,900 --> 00:13:12,500 it isn't entirely blocked, right? 308 00:13:12,500 --> 00:13:13,933 It filters through the outer edges 309 00:13:13,933 --> 00:13:15,866 of the planetary atmosphere, 310 00:13:15,866 --> 00:13:19,400 and that outer edges imprints on that starlight. 311 00:13:19,400 --> 00:13:21,133 The starlight keeps coming to us on Earth 312 00:13:21,133 --> 00:13:23,600 from the outer edges of the atmosphere imprint on it, 313 00:13:23,600 --> 00:13:24,800 and that is what allows us 314 00:13:24,800 --> 00:13:27,100 to measure the atmospheric composition 315 00:13:27,100 --> 00:13:28,266 of these planets, right? 316 00:13:28,266 --> 00:13:29,466 We never actually see the planet. 317 00:13:29,466 --> 00:13:31,633 We just see it pass in front of the star, 318 00:13:31,633 --> 00:13:34,266 but because of that little fringe of atmosphere, 319 00:13:34,266 --> 00:13:37,400 we can measure what's going on in the exoplanet atmosphere. 320 00:13:37,400 --> 00:13:42,066 And this was first done about just under 20 years ago 321 00:13:42,066 --> 00:13:48,066 for a planet called HD 219--209458. 322 00:13:48,066 --> 00:13:52,500 Most planet names are complete telephone numbers. 323 00:13:52,500 --> 00:13:53,900 They're named after star catalog names. 324 00:13:53,900 --> 00:13:55,900 Like I said, you never get to name an exoplanet 325 00:13:55,900 --> 00:13:57,200 after yourself. 326 00:13:57,200 --> 00:14:00,633 You get to name it after the star catalog that it's in. 327 00:14:00,633 --> 00:14:02,100 But if you do this long enough, 328 00:14:02,100 --> 00:14:03,900 you get to remember the telephone numbers, as well, 329 00:14:03,900 --> 00:14:06,566 so it was first done on a planet called HD 209458, 330 00:14:06,566 --> 00:14:08,000 it's well-known in the community, 331 00:14:08,000 --> 00:14:10,433 and now we've done it for a whole bunch of exoplanets 332 00:14:10,433 --> 00:14:15,600 using telescopes like Hubble and things from the ground. 333 00:14:15,600 --> 00:14:18,000 But the really exciting thing is to do this 334 00:14:18,000 --> 00:14:19,733 with the James Webb Space Telescope, 335 00:14:19,733 --> 00:14:21,733 and this is the new telescope that was just launched 336 00:14:21,733 --> 00:14:25,433 two years ago, and is really-- 337 00:14:25,433 --> 00:14:27,466 You know, saying it's gonna usher in a new era 338 00:14:27,466 --> 00:14:30,033 of, you know, exoplanet atmosphere studies 339 00:14:30,033 --> 00:14:32,133 is probably understating what's about to happen 340 00:14:32,133 --> 00:14:34,333 over the next couple of years. 341 00:14:34,333 --> 00:14:40,033 So launch for James Webb was Christmas Day of 2020 342 00:14:40,033 --> 00:14:42,500 from French Guiana. 343 00:14:42,500 --> 00:14:45,166 As was mentioned in the introduction, 344 00:14:45,166 --> 00:14:47,566 I worked on one of the Webb instrument teams, 345 00:14:47,566 --> 00:14:49,900 one of the JWST instrument teams, 346 00:14:49,900 --> 00:14:52,766 specifically on a camera called NIRCam. 347 00:14:52,766 --> 00:14:55,700 That's one of the 4 instruments on the spacecraft, 348 00:14:55,700 --> 00:14:59,366 and so all of us were online to watch the launch. 349 00:14:59,366 --> 00:15:02,433 Actually, what happened is, I was at my in-laws in Chicago, 350 00:15:02,433 --> 00:15:03,633 and I have two young children, 351 00:15:03,633 --> 00:15:07,400 and so we did presents for about an hour, 352 00:15:07,400 --> 00:15:09,666 and then launch was at 6:15, 353 00:15:09,666 --> 00:15:12,533 so we woke up at 5:00 A.M., did presents for about an hour, 354 00:15:12,533 --> 00:15:16,666 and then we all went and watched the launch for-- 355 00:15:16,666 --> 00:15:20,166 you know, in the middle of Christmas morning. 356 00:15:20,166 --> 00:15:22,766 And I will tell you, 357 00:15:22,766 --> 00:15:26,566 my mother-in-law, who's very nice, 358 00:15:26,566 --> 00:15:28,900 she's a wonderful woman, and you guys would love her, 359 00:15:28,900 --> 00:15:33,300 but she also, you know, she thought, she understood 360 00:15:33,300 --> 00:15:36,666 how important this was to me professionally, right? 361 00:15:36,666 --> 00:15:38,933 Like, if this exploded on launch, 362 00:15:38,933 --> 00:15:42,033 it was unclear I was gonna have a job the next day, right? 363 00:15:42,033 --> 00:15:44,166 There was a lot riding on this, 364 00:15:44,166 --> 00:15:46,900 but also her conception of this was, 365 00:15:46,900 --> 00:15:50,233 if the rocket ignited and we were going, we were done, right? 366 00:15:50,233 --> 00:15:52,266 And in reality, you know, 367 00:15:52,266 --> 00:15:54,766 the rocket can blow up at any time, right? 368 00:15:54,766 --> 00:15:58,666 And once you get off-- actually, the real sticking point 369 00:15:58,666 --> 00:16:01,566 was as soon as JWST came off the top of the rocket, 370 00:16:01,566 --> 00:16:03,600 it was on battery power, 371 00:16:03,600 --> 00:16:05,933 and the batteries last for about 20 minutes, 372 00:16:05,933 --> 00:16:08,033 and so it has to deploy a solar panel 373 00:16:08,033 --> 00:16:10,600 and start generating electricity as soon as it can, 374 00:16:10,600 --> 00:16:12,233 and if that solar panel didn't deploy, 375 00:16:12,233 --> 00:16:14,433 you had 20 minutes to figure out what was going on, 376 00:16:14,433 --> 00:16:15,633 and then you were done, right? 377 00:16:15,633 --> 00:16:17,166 There was no way to recover it. 378 00:16:17,166 --> 00:16:19,800 And one of the best things I ever saw in my life was, 379 00:16:19,800 --> 00:16:22,266 there's video feed from the launch 380 00:16:22,266 --> 00:16:25,566 of, you know, Webb detaching from the upper stage, 381 00:16:25,566 --> 00:16:27,666 and you could immediately see the solar panel coming out, 382 00:16:27,666 --> 00:16:29,266 and we were all on the internal comms, 383 00:16:29,266 --> 00:16:30,533 and you could hear them reporting 384 00:16:30,533 --> 00:16:32,233 that power was starting to be generated, 385 00:16:32,233 --> 00:16:34,133 and everybody started cheering because we knew that, 386 00:16:34,133 --> 00:16:36,400 you know, the first hurdle was overcome. 387 00:16:36,400 --> 00:16:38,066 But my mother-in-law, who's a wonderful woman, 388 00:16:38,066 --> 00:16:40,966 thought as we were, like, 30 seconds in and the rocket 389 00:16:40,966 --> 00:16:42,800 was firing that, you know, everything was great, 390 00:16:42,800 --> 00:16:44,866 and so we're 30 seconds in and the rocket's firing, 391 00:16:44,866 --> 00:16:46,266 and she comes over, and she's like, 392 00:16:46,266 --> 00:16:47,433 "Thomas, you did it. 393 00:16:47,433 --> 00:16:50,333 Like, it's all happening, congratulations," 394 00:16:50,333 --> 00:16:52,666 and I just was like, "Not now, Cindy." 395 00:16:52,666 --> 00:16:55,500 [audience laughing] 396 00:16:55,500 --> 00:16:57,500 But she's very nice. 397 00:16:57,500 --> 00:17:00,466 So there's a couple of exciting things about Webb. 398 00:17:00,466 --> 00:17:03,333 One of them-- and this still boggles my mind, 399 00:17:03,333 --> 00:17:06,800 even having known this for, you know, years, right-- 400 00:17:06,800 --> 00:17:11,166 is that Webb is about three times as large as Hubble, 401 00:17:11,166 --> 00:17:13,833 but the mirror weighs half as much, right? 402 00:17:13,833 --> 00:17:16,433 And the collecting area you get from a mirror 403 00:17:16,433 --> 00:17:18,533 is the area, right, so if it's three times larger, 404 00:17:18,533 --> 00:17:21,300 that means you get almost 10 times as much light 405 00:17:21,300 --> 00:17:22,733 in the same amount of time, 406 00:17:22,733 --> 00:17:24,866 so it's about 10 times more powerful than Hubble. 407 00:17:24,866 --> 00:17:26,033 It weighs half as much. 408 00:17:26,033 --> 00:17:27,633 It's really an incredible machine, 409 00:17:27,633 --> 00:17:31,566 and the amount of attention to detail and design 410 00:17:31,566 --> 00:17:34,033 that went into it really just boggles the mind. 411 00:17:34,033 --> 00:17:35,666 The other difference from Hubble is that Webb 412 00:17:35,666 --> 00:17:37,233 is an infrared telescope. 413 00:17:37,233 --> 00:17:41,200 So Hubble observes a little bit into the infrared, 414 00:17:41,200 --> 00:17:43,200 but fundamentally is an optical telescope, 415 00:17:43,200 --> 00:17:45,033 but observed very close to the wavelengths-- 416 00:17:45,033 --> 00:17:47,233 to the kind of light that we see with our eyes. 417 00:17:47,233 --> 00:17:48,666 And Webb's observes very different wavelengths 418 00:17:48,666 --> 00:17:51,666 and longer wavelengths, the infrared, you know, 419 00:17:51,666 --> 00:17:56,533 closer to the heat that you see in images of heat. 420 00:17:56,533 --> 00:17:59,033 So one thing this allows us to do is it allows us 421 00:17:59,033 --> 00:18:02,366 to probe deeper into the atmospheres of exoplanets. 422 00:18:02,366 --> 00:18:04,733 So this is a picture of Jupiter taken in the infrared. 423 00:18:04,733 --> 00:18:07,833 You can see the sort of bands and clouds where, you know, 424 00:18:07,833 --> 00:18:11,566 you maybe are used to seeing in optical images of Jupiter. 425 00:18:11,566 --> 00:18:14,300 Here's the Great Red Spot, just for reference, right, 426 00:18:14,300 --> 00:18:16,333 that sort of dark, circle-ish thing. 427 00:18:16,333 --> 00:18:18,433 The bright parts here 428 00:18:18,433 --> 00:18:21,000 are really hot parts of Jupiter, right? 429 00:18:21,000 --> 00:18:22,766 What that means is, those bright parts are 430 00:18:22,766 --> 00:18:24,433 you are seeing through the clouds 431 00:18:24,433 --> 00:18:27,166 into the interior of the planet, where it is hotter. 432 00:18:27,166 --> 00:18:29,033 So the darker parts are the upper clouds 433 00:18:29,033 --> 00:18:31,433 that usually that's what we see when we look in visible light 434 00:18:31,433 --> 00:18:33,133 and hotter and deeper, 435 00:18:33,133 --> 00:18:35,166 we can actually see with these infrared images, 436 00:18:35,166 --> 00:18:37,300 and we usually can't see that in the optical. 437 00:18:37,300 --> 00:18:39,500 We also see different molecules in the infrared. 438 00:18:39,500 --> 00:18:41,100 We get to see a lot of methane. 439 00:18:41,100 --> 00:18:45,100 We get to see a lot of ozone and water and carbon dioxide, 440 00:18:45,100 --> 00:18:47,100 which we couldn't really see easily, 441 00:18:47,100 --> 00:18:49,700 particularly in exoplanet observations. 442 00:18:49,700 --> 00:18:52,033 As a little bit of color, 443 00:18:52,033 --> 00:18:55,066 so launch for Webb was Christmas morning, 444 00:18:55,066 --> 00:18:57,166 and then we all spent 445 00:18:57,166 --> 00:19:01,200 the next six months traveling out to Baltimore one week-- 446 00:19:01,200 --> 00:19:04,566 a little over a week a month for six months straight 447 00:19:04,566 --> 00:19:06,700 to operate the telescope during commissioning, 448 00:19:06,700 --> 00:19:08,000 because it launches 449 00:19:08,000 --> 00:19:10,200 and then it needs to be checked out before NASA will, 450 00:19:10,200 --> 00:19:12,333 you know, accept it as an operating observatory. 451 00:19:12,333 --> 00:19:14,133 So, as some local color, 452 00:19:14,133 --> 00:19:16,133 here's what my office looked like 453 00:19:16,133 --> 00:19:19,266 for most of those six months during commissioning, 454 00:19:19,266 --> 00:19:20,833 helping to run the telescope. 455 00:19:20,833 --> 00:19:22,500 The really helpful thing, right, 456 00:19:22,500 --> 00:19:24,866 is that most of this is color-coded, right? 457 00:19:24,866 --> 00:19:27,266 It turns out that there are actually very few people 458 00:19:27,266 --> 00:19:29,433 that know what all those numbers mean, 459 00:19:29,433 --> 00:19:30,600 right, not even me. 460 00:19:30,600 --> 00:19:32,700 I knew my part, but most of these, 461 00:19:32,700 --> 00:19:36,033 what was happening, like, other people understood. 462 00:19:36,033 --> 00:19:38,533 It was sort of a fascinating project that no one person 463 00:19:38,533 --> 00:19:40,300 can really hold it all in their head, 464 00:19:40,300 --> 00:19:42,166 except there was one guy, right? 465 00:19:42,166 --> 00:19:45,066 The real job that we all had was to look at these screens 466 00:19:45,066 --> 00:19:49,166 and if anything turned red, we were gonna call Carl, right, 467 00:19:49,166 --> 00:19:52,700 'cause Carl knows what all these numbers mean 468 00:19:52,700 --> 00:19:55,333 and knows if they turn red, what to do about it, 469 00:19:55,333 --> 00:19:58,733 or at least he knows who to talk to, right? 470 00:20:00,133 --> 00:20:02,266 I'll also say that we-- 471 00:20:02,266 --> 00:20:04,266 most of the shifts, they were eight-hour shifts, 472 00:20:04,266 --> 00:20:05,966 and we were there most of the day. 473 00:20:05,966 --> 00:20:07,300 We did have to observe. 474 00:20:07,300 --> 00:20:09,100 We had to be there overnight some weeks, 475 00:20:09,100 --> 00:20:11,600 which I felt was particularly unjust for a space telescope 476 00:20:11,600 --> 00:20:14,200 where you don't actually usually have to be up overnight. 477 00:20:14,200 --> 00:20:15,833 The one nice thing is, 478 00:20:15,833 --> 00:20:19,666 we actually ended up watching a fair amount of movies, 479 00:20:19,666 --> 00:20:22,366 and this is a photograph of-- 480 00:20:22,366 --> 00:20:24,800 So we were all in a room called Science-- 481 00:20:24,800 --> 00:20:28,000 the Science Instrument Room, the SI Room, 482 00:20:28,000 --> 00:20:29,800 and right next to us in a separate room 483 00:20:29,800 --> 00:20:31,600 was Flight Operations, Flight Ops. 484 00:20:31,600 --> 00:20:34,566 This is a photograph of all the Flight Ops desks. 485 00:20:34,566 --> 00:20:36,233 They were the people who actually sent commands 486 00:20:36,233 --> 00:20:38,733 to the spacecraft. 487 00:20:38,733 --> 00:20:42,766 And you will notice, if you look very carefully, 488 00:20:42,766 --> 00:20:44,933 right up here at that image, 489 00:20:44,933 --> 00:20:49,300 Flight Ops is currently watching Olympic curling 490 00:20:49,300 --> 00:20:52,266 on the big screens at the front of the room, right? 491 00:20:52,266 --> 00:20:54,866 So most of the movies we watched were actually stuff 492 00:20:54,866 --> 00:20:56,533 that Flight Ops set up and put on, 493 00:20:56,533 --> 00:20:58,800 and they also get to choose the movies, 494 00:20:58,800 --> 00:21:01,266 and they had a very interesting-- 495 00:21:01,266 --> 00:21:03,633 I really wanna know who was in charge of this 496 00:21:03,633 --> 00:21:05,233 'cause we spent about a week working through 497 00:21:05,233 --> 00:21:07,666 all the Princess Diaries movies. 498 00:21:07,666 --> 00:21:10,533 Then we did really trashy sci-fi movies. 499 00:21:10,533 --> 00:21:12,933 Have you guys ever seen Moonfall? 500 00:21:12,933 --> 00:21:15,500 Like, the moon comes alive and crashes into the Earth. 501 00:21:15,500 --> 00:21:17,700 Yeah, that's what we watched. 502 00:21:17,700 --> 00:21:20,400 It was not what I would have expected 503 00:21:20,400 --> 00:21:25,066 for a bunch of NASA engineers in the other room. 504 00:21:25,066 --> 00:21:28,333 Okay, so that's a little bit of color from commissioning, 505 00:21:28,333 --> 00:21:31,666 but to get back to the serious part of the talk, right, 506 00:21:31,666 --> 00:21:34,666 how can we use JWST to search for life, right? 507 00:21:34,666 --> 00:21:37,433 Now that we have this machine, this observatory in space, 508 00:21:37,433 --> 00:21:41,766 we want to use it to search for life with its giant mirror. 509 00:21:41,766 --> 00:21:43,733 How do we do that? 510 00:21:43,733 --> 00:21:46,000 So one thing is that often 511 00:21:46,000 --> 00:21:48,866 when we think about other life in the universe, right, 512 00:21:48,866 --> 00:21:52,800 a lot of what we think about is other intelligent life, right? 513 00:21:52,800 --> 00:21:55,633 Like, we're thinking about some sort of, like, 514 00:21:55,633 --> 00:21:58,666 face-sucking alien that's gonna, like, read your mind 515 00:21:58,666 --> 00:22:02,566 or, like, you know, the alien from Aliens, right? 516 00:22:02,566 --> 00:22:06,066 But there's other kinds of life out in the universe, right? 517 00:22:06,066 --> 00:22:08,533 And when we're talking about in the astronomical context 518 00:22:08,533 --> 00:22:11,733 searching for life, we're not just meaning intelligent life. 519 00:22:11,733 --> 00:22:15,133 We also mean plants and bacteria and animals and, really, 520 00:22:15,133 --> 00:22:18,433 any kind of life, any kind of life out there 521 00:22:18,433 --> 00:22:21,100 that would be something like life on Earth. 522 00:22:23,233 --> 00:22:25,400 So what that means is that a lot of people 523 00:22:25,400 --> 00:22:27,500 spend a lot of time thinking about 524 00:22:27,500 --> 00:22:30,066 what, exactly, do we mean by life, right? 525 00:22:30,066 --> 00:22:31,800 Like, what does that actually mean? 526 00:22:31,800 --> 00:22:33,466 Like, what is that? 527 00:22:33,466 --> 00:22:35,666 And I'll say it's a topic of a lot of debate. 528 00:22:35,666 --> 00:22:37,500 I've gone to a lot of conferences where people 529 00:22:37,500 --> 00:22:40,300 spend a lot of time discussing exactly what it means. 530 00:22:40,300 --> 00:22:43,200 My personal favorite definition-- 531 00:22:43,200 --> 00:22:44,800 Well, I've written it on the slide, right? 532 00:22:44,800 --> 00:22:45,966 It's, life is some sort 533 00:22:45,966 --> 00:22:48,633 of self-organized chemical structure 534 00:22:48,633 --> 00:22:52,133 that alters its environment and can reproduce. 535 00:22:52,133 --> 00:22:53,300 To me, that seems like 536 00:22:53,300 --> 00:22:56,033 a pretty general, basic statement 537 00:22:56,033 --> 00:22:57,733 that tries to be pretty agnostic 538 00:22:57,733 --> 00:22:59,833 about what, exactly, life is, right? 539 00:22:59,833 --> 00:23:01,500 So we're not just looking for intelligent life. 540 00:23:01,500 --> 00:23:05,433 We're looking for just life as a general category of objects. 541 00:23:05,433 --> 00:23:08,166 On Earth, all of the life on Earth 542 00:23:08,166 --> 00:23:11,900 is based fundamentally around DNA, right, 543 00:23:11,900 --> 00:23:16,400 which is some assembly of hydrogen, oxygen, 544 00:23:16,400 --> 00:23:18,933 nitrogen, carbon, and phosphorus, right? 545 00:23:18,933 --> 00:23:22,333 The backbone of most of these molecules are carbon molecules. 546 00:23:22,333 --> 00:23:25,000 That's why we say that life on Earth is carbon-based. 547 00:23:25,000 --> 00:23:27,333 It's why organic chemistry exists as a subfield. 548 00:23:27,333 --> 00:23:29,900 Organic chemistry is just carbon molecules 549 00:23:29,900 --> 00:23:32,966 and carbon chemistry, right, because it's a fundamental part 550 00:23:32,966 --> 00:23:34,966 of all of our lives of everything on Earth. 551 00:23:37,300 --> 00:23:41,033 And life on Earth also requires liquid water, right? 552 00:23:41,033 --> 00:23:43,666 The reason for that is that all the chemical reactions 553 00:23:43,666 --> 00:23:47,133 that happen in your body need some sort of liquid suspension 554 00:23:47,133 --> 00:23:48,966 for it to occur in, right? 555 00:23:48,966 --> 00:23:50,633 It's hard to get chemistry to happen 556 00:23:50,633 --> 00:23:52,100 just dry on the floor. 557 00:23:52,100 --> 00:23:54,766 We need some liquid to allow things to mix, 558 00:23:54,766 --> 00:23:57,133 and you can dissolve a lot of things in water, right? 559 00:23:57,133 --> 00:23:59,633 Water is sometimes referred to as the universal solvent. 560 00:23:59,633 --> 00:24:01,933 So life on Earth, we need liquid water. 561 00:24:01,933 --> 00:24:04,300 We need a lot of carbon, oxygen, nitrogen, 562 00:24:04,300 --> 00:24:06,600 maybe a little bit of phosphorus. 563 00:24:06,600 --> 00:24:09,033 Okay, so what about life on other planets, right? 564 00:24:09,033 --> 00:24:11,033 If we think about what life looks like on Earth, 565 00:24:11,033 --> 00:24:13,233 then what does that tell us about where do we look 566 00:24:13,233 --> 00:24:15,300 for life on other planets? 567 00:24:15,300 --> 00:24:18,766 Well, first thing is, we need an ocean, right? 568 00:24:18,766 --> 00:24:20,566 If we want to find life like the Earth, 569 00:24:20,566 --> 00:24:23,266 we need to have liquid water present on the surface, 570 00:24:23,266 --> 00:24:25,266 enough liquid water for it to be a fundamental part 571 00:24:25,266 --> 00:24:28,433 of the biology, just like it is for us. 572 00:24:28,433 --> 00:24:31,166 It's actually an interesting point 573 00:24:31,166 --> 00:24:32,800 about the Earth's oceans, right? 574 00:24:32,800 --> 00:24:35,200 And it's actually a very fine point that a lot of people 575 00:24:35,200 --> 00:24:37,700 are thinking about as we think about oceans on other worlds. 576 00:24:37,700 --> 00:24:39,500 'Cause if you think about it, if Earth had 577 00:24:39,500 --> 00:24:42,166 a little bit more water, just a little bit more water, 578 00:24:42,166 --> 00:24:44,666 the surface would be entirely covered by ocean, right? 579 00:24:44,666 --> 00:24:45,833 There'd be no land. 580 00:24:45,833 --> 00:24:47,633 It would just be water all the way down. 581 00:24:47,633 --> 00:24:49,200 Well, until you hit the sea floor. 582 00:24:49,200 --> 00:24:51,000 And if we had a little bit less water, 583 00:24:51,000 --> 00:24:52,266 there wouldn't be any oceans. 584 00:24:52,266 --> 00:24:54,166 We'd be something like Mars, where there is water, 585 00:24:54,166 --> 00:24:55,833 but it's frozen into the polar icecaps, 586 00:24:55,833 --> 00:24:57,400 or it's in ice underground. 587 00:24:57,400 --> 00:24:59,900 It's not just standing water on the surface. 588 00:24:59,900 --> 00:25:02,966 So Earth, at least right now, seems to be 589 00:25:02,966 --> 00:25:06,633 a pretty finely balanced midpoint 590 00:25:06,633 --> 00:25:08,966 between those two extremes, and it seems very convenient 591 00:25:08,966 --> 00:25:10,766 that we happen to live on the one planet 592 00:25:10,766 --> 00:25:14,233 that just happens to hit that exact point. 593 00:25:14,233 --> 00:25:16,033 Now, maybe that's reading too much into it, right? 594 00:25:16,033 --> 00:25:17,200 We only have one example. 595 00:25:17,200 --> 00:25:18,400 Maybe we're gonna go out there, 596 00:25:18,400 --> 00:25:20,000 and we're gonna discover tons of ocean worlds, 597 00:25:20,000 --> 00:25:22,000 and it's gonna be great, or maybe we're gonna discover 598 00:25:22,000 --> 00:25:24,466 tons of life that lives on ice and melts it-- 599 00:25:24,466 --> 00:25:26,400 or I don't know what, right? 600 00:25:26,400 --> 00:25:28,066 But just something to think about. 601 00:25:28,066 --> 00:25:29,866 But the fact that we have oceans on Earth 602 00:25:29,866 --> 00:25:33,366 is actually very coincidental, seems to be very finely tuned. 603 00:25:35,366 --> 00:25:36,866 Another thing we also need is, 604 00:25:36,866 --> 00:25:39,000 we need the right temperature, right? 605 00:25:39,000 --> 00:25:40,400 We need the right amount of water. 606 00:25:40,400 --> 00:25:41,666 We need the right temperature, right? 607 00:25:41,666 --> 00:25:44,066 If Earth gets too hot, if it moves in a little bit 608 00:25:44,066 --> 00:25:46,500 closer to the Sun, all the water boils off into steam. 609 00:25:46,500 --> 00:25:48,800 If it moves too far out, it all freezes, 610 00:25:48,800 --> 00:25:52,200 it turns into ice, and we're a giant snowball. 611 00:25:52,200 --> 00:25:54,200 So one of the fundamental things we wanna look for 612 00:25:54,200 --> 00:25:57,133 when we're looking for potentially habitable planets 613 00:25:57,133 --> 00:25:58,333 is we wanna look for planets 614 00:25:58,333 --> 00:26:00,566 that are at the right distance from their stars, 615 00:26:00,566 --> 00:26:03,433 that are in the habitable zone, or the Goldilocks zone, 616 00:26:03,433 --> 00:26:06,266 the right temperature so that liquid water can exist 617 00:26:06,266 --> 00:26:08,266 on the surface of these planets. 618 00:26:09,266 --> 00:26:11,500 And we actually have a bunch of these, right? 619 00:26:11,500 --> 00:26:13,866 These are actual real planets. 620 00:26:13,866 --> 00:26:15,366 The images are not real, right? 621 00:26:15,366 --> 00:26:17,033 These are all artists' conceptions, 622 00:26:17,033 --> 00:26:20,500 but these are all actual planets that we have detected 623 00:26:20,500 --> 00:26:23,100 and are about the size of the Earth 624 00:26:23,100 --> 00:26:25,066 and are at the right distance from their stars 625 00:26:25,066 --> 00:26:28,000 to support liquid water on their surfaces, right? 626 00:26:28,000 --> 00:26:29,466 We actually know about a whole bunch 627 00:26:29,466 --> 00:26:31,300 of potentially habitable planets that we could go 628 00:26:31,300 --> 00:26:33,633 and search for life on them. 629 00:26:33,633 --> 00:26:35,866 So, okay, so we've detected a whole bunch of planets. 630 00:26:35,866 --> 00:26:37,266 We have this nice light curve, right? 631 00:26:37,266 --> 00:26:38,600 What happens next? 632 00:26:38,600 --> 00:26:40,800 How do we figure out if we have a beach vacation 633 00:26:40,800 --> 00:26:43,666 or if we have Venus, right? 634 00:26:43,666 --> 00:26:45,466 Now that we know these planets are out there, 635 00:26:45,466 --> 00:26:47,133 how do we look at their atmospheres 636 00:26:47,133 --> 00:26:50,333 and figure out if they actually might have life? 637 00:26:50,333 --> 00:26:52,500 Well, we primarily wanna look for three things 638 00:26:52,500 --> 00:26:53,666 in the atmosphere. 639 00:26:53,666 --> 00:26:56,800 So first, we wanna look for water, right? 640 00:26:56,800 --> 00:26:58,333 We wanna confirm that there's 641 00:26:58,333 --> 00:26:59,833 some sort of water in the system. 642 00:26:59,833 --> 00:27:01,566 Well, it's the right temperature for liquid water, 643 00:27:01,566 --> 00:27:06,400 but we don't know if liquid water is there until we see it. 644 00:27:06,400 --> 00:27:08,666 We also want to look for oxygen, right? 645 00:27:08,666 --> 00:27:10,866 20% of the air you're breathing right now is oxygen. 646 00:27:10,866 --> 00:27:13,600 It's a major component of our atmosphere on Earth. 647 00:27:13,600 --> 00:27:15,000 And we also wanna look for methane, 648 00:27:15,000 --> 00:27:17,666 but probably not too much, right? 649 00:27:17,666 --> 00:27:22,266 It's one of the major biological products from life on Earth. 650 00:27:22,266 --> 00:27:24,766 The main biosignature, right, 651 00:27:24,766 --> 00:27:28,033 thing you would want to look for in an atmosphere, is oxygen. 652 00:27:28,033 --> 00:27:31,566 It's often considered a primary biosignature, 653 00:27:31,566 --> 00:27:36,633 and the reason for that is that without life on Earth, 654 00:27:36,633 --> 00:27:38,500 the level of oxygen in our air 655 00:27:38,500 --> 00:27:40,933 would be about a million times lower, right? 656 00:27:40,933 --> 00:27:42,300 So when the Earth first formed, 657 00:27:42,300 --> 00:27:45,600 there was almost zero oxygen in the atmosphere of the planet, 658 00:27:45,600 --> 00:27:48,600 and the only reason why the air you are breathing right now 659 00:27:48,600 --> 00:27:51,966 is 20% oxygen is because life evolved 660 00:27:51,966 --> 00:27:56,833 and started photosynthesizing, so the fact that 1/5 of our air 661 00:27:56,833 --> 00:27:59,400 is composed out of oxygen molecules is solely due 662 00:27:59,400 --> 00:28:00,633 to life on Earth. 663 00:28:00,633 --> 00:28:01,833 If all the life on Earth 664 00:28:01,833 --> 00:28:03,466 suddenly blinked out of existence tomorrow, 665 00:28:03,466 --> 00:28:05,266 all the oxygen would be gone from our atmosphere 666 00:28:05,266 --> 00:28:07,833 within probably a couple thousand years, 667 00:28:07,833 --> 00:28:10,200 very quick on an astronomical time scale. 668 00:28:10,200 --> 00:28:13,066 So if we were looking at an exoplanet 669 00:28:13,066 --> 00:28:14,833 and we saw some water in the atmosphere 670 00:28:14,833 --> 00:28:18,166 and we saw oxygen, 671 00:28:18,166 --> 00:28:20,366 I mean, there's probably a couple more steps, 672 00:28:20,366 --> 00:28:22,066 but you could probably think about writing 673 00:28:22,066 --> 00:28:25,300 your Nobel Prize acceptance speech at that point, right? 674 00:28:25,300 --> 00:28:28,633 It's a really strong signal that we've got 675 00:28:28,633 --> 00:28:31,400 a good, promising candidate. 676 00:28:31,400 --> 00:28:33,200 One of the best candidates to look for this, 677 00:28:33,200 --> 00:28:35,800 a lot of people are spending a lot of time looking at this, 678 00:28:35,800 --> 00:28:38,100 is a system called TRAPPIST-1. 679 00:28:38,100 --> 00:28:39,666 These are a whole bunch of planets, 680 00:28:39,666 --> 00:28:42,200 and a bunch of them are in the habitable zone, 681 00:28:42,200 --> 00:28:43,833 so it's a very small star. 682 00:28:43,833 --> 00:28:45,000 They're all very close in, 683 00:28:45,000 --> 00:28:47,200 but they're all in the habitable zone. 684 00:28:47,200 --> 00:28:51,633 Two of these have already been looked at with James Webb. 685 00:28:51,633 --> 00:28:54,066 I was actually involved with looking at-- 686 00:28:54,066 --> 00:28:58,300 the team that looked at the innermost one, TRAPPIST-1b, 687 00:28:58,300 --> 00:29:01,433 where we measured what it looked like for the first time, 688 00:29:01,433 --> 00:29:03,266 and, unfortunately, the answer was, 689 00:29:03,266 --> 00:29:05,933 it looks like a bare rock in space, 690 00:29:05,933 --> 00:29:08,533 that the atmosphere has been completely blasted off. 691 00:29:08,533 --> 00:29:11,866 I was actually sitting with the guy who was analyzing the data. 692 00:29:11,866 --> 00:29:13,600 The whole observation was designed to take, 693 00:29:13,600 --> 00:29:15,233 like, five separate transits, 694 00:29:15,233 --> 00:29:17,333 and we were gonna have to add them all together 695 00:29:17,333 --> 00:29:19,966 before we thought we were gonna get anything, 696 00:29:19,966 --> 00:29:22,166 and I was sitting next to him when he first downloaded 697 00:29:22,166 --> 00:29:24,633 the first data from the first observation, 698 00:29:24,633 --> 00:29:28,333 and you could just see it, like, in the first one. 699 00:29:28,333 --> 00:29:30,333 And we both looked at each other, and we're like, 700 00:29:30,333 --> 00:29:33,666 "Well, that is not really the answer we wanted," 701 00:29:33,666 --> 00:29:35,766 because it means it was a very hot rock, 702 00:29:35,766 --> 00:29:37,766 the fact that we could see it the first time. 703 00:29:37,766 --> 00:29:40,866 So actually, it's telling us a lot about how planets 704 00:29:40,866 --> 00:29:44,033 lose atmospheres if they're very close to their stars, 705 00:29:44,033 --> 00:29:45,266 and then the second one, 706 00:29:45,266 --> 00:29:47,933 TRAPPIST-1c, is more Venus-like, it turns out, 707 00:29:47,933 --> 00:29:50,766 from other Webb observations, 708 00:29:50,766 --> 00:29:54,800 but there are a lot of people looking at E and F and G to try 709 00:29:54,800 --> 00:29:58,433 and get much finer observations of their atmospheres. 710 00:29:58,433 --> 00:30:00,733 So there's a lot of people looking for Earth-like life. 711 00:30:00,733 --> 00:30:03,066 Another thing we can do is look for life, 712 00:30:03,066 --> 00:30:05,233 but maybe not quite as we know it, right, 713 00:30:05,233 --> 00:30:06,700 not quite like the Earth. 714 00:30:06,700 --> 00:30:08,100 And so I mentioned that the Earth-- 715 00:30:08,100 --> 00:30:09,500 We seem to be very finely tuned 716 00:30:09,500 --> 00:30:11,866 in terms of having land and an ocean, right? 717 00:30:11,866 --> 00:30:14,600 What if we looked not at planets like the Earth, 718 00:30:14,600 --> 00:30:16,433 but what if we looked at water worlds, 719 00:30:16,433 --> 00:30:18,066 giant water worlds 720 00:30:18,066 --> 00:30:21,033 that are somewhere in between the Earth and Neptune? 721 00:30:22,566 --> 00:30:25,400 So these are called hycean planets. 722 00:30:25,400 --> 00:30:27,200 This was sort of a category of planets 723 00:30:27,200 --> 00:30:29,566 that was suggested a couple of years ago, 724 00:30:29,566 --> 00:30:31,966 and the idea is that it's not a planet like the Earth. 725 00:30:31,966 --> 00:30:34,066 It's probably about five or even ten times 726 00:30:34,066 --> 00:30:35,666 more massive than the Earth, 727 00:30:35,666 --> 00:30:38,166 much larger, but there's a lot of water, 728 00:30:38,166 --> 00:30:39,533 and there's a hydrogen envelope, 729 00:30:39,533 --> 00:30:41,733 a hydrogen atmosphere that insulates that water, 730 00:30:41,733 --> 00:30:43,733 and so you can have a liquid water ocean 731 00:30:43,733 --> 00:30:46,333 at the right temperature, at about room temperature, 732 00:30:46,333 --> 00:30:48,400 and you could maybe have volcanism 733 00:30:48,400 --> 00:30:49,866 or something going on underneath, 734 00:30:49,866 --> 00:30:51,666 and so you could have a liquid water ocean 735 00:30:51,666 --> 00:30:53,666 at the right temperature with energy being put into it, 736 00:30:53,666 --> 00:30:58,833 and you could have life present on these planets, right? 737 00:30:58,833 --> 00:31:00,700 That wouldn't be life like the Earth. 738 00:31:00,700 --> 00:31:02,633 It may not even be intelligent life, 739 00:31:02,633 --> 00:31:04,100 but it would be life, right, 740 00:31:04,100 --> 00:31:05,833 and that would be very exciting to find, 741 00:31:05,833 --> 00:31:07,833 and these are much bigger planets, 742 00:31:07,833 --> 00:31:12,066 and so they're much easier to measure the atmospheres for. 743 00:31:14,566 --> 00:31:18,900 And so actually, at University of Wisconsin, 744 00:31:18,900 --> 00:31:22,100 we actually have time on a telescope out in Arizona. 745 00:31:22,100 --> 00:31:25,766 We get about 20 nights a year on the WIYN telescope, 746 00:31:25,766 --> 00:31:27,900 and one of the things that I do is 747 00:31:27,900 --> 00:31:33,766 I use some of that time to look for planets like these, 748 00:31:33,766 --> 00:31:36,233 and I actually have a student working with me right now 749 00:31:36,233 --> 00:31:37,866 who's working on this. 750 00:31:37,866 --> 00:31:39,900 He's actually-- 751 00:31:39,900 --> 00:31:42,933 Pretty excitingly, he's actually found two of these this spring 752 00:31:42,933 --> 00:31:46,566 where we're starting to write up that paper right now, right? 753 00:31:46,566 --> 00:31:50,133 Two new planets in this category that this fall, 754 00:31:50,133 --> 00:31:51,733 we're gonna apply for James Webb time 755 00:31:51,733 --> 00:31:54,933 to try and look at what the atmospheres are like, right? 756 00:31:54,933 --> 00:31:56,933 We're actually-- 757 00:31:56,933 --> 00:31:58,800 Well, Arizona is two hours behind us, 758 00:31:58,800 --> 00:32:00,966 so they're probably opening up 759 00:32:00,966 --> 00:32:02,366 probably in about an hour from now 760 00:32:02,366 --> 00:32:03,966 to start observing tonight, and they're gonna be 761 00:32:03,966 --> 00:32:06,600 observing again for us tonight, as well, right? 762 00:32:06,600 --> 00:32:09,766 So we're actually doing this search tonight 763 00:32:09,766 --> 00:32:12,766 to look for planets like these. 764 00:32:12,766 --> 00:32:15,100 And the exciting thing is, 765 00:32:15,100 --> 00:32:18,366 is that, because these are so large, 766 00:32:18,366 --> 00:32:19,933 they're actually pretty-- 767 00:32:19,933 --> 00:32:21,566 the atmospheres are pretty detectable 768 00:32:21,566 --> 00:32:23,333 with James Webb observations, 769 00:32:23,333 --> 00:32:26,833 so JWST in one to four transit observations, 770 00:32:26,833 --> 00:32:30,266 which is a pretty reasonable request to ask for time 771 00:32:30,266 --> 00:32:33,000 on the telescope, could look at these planets 772 00:32:33,000 --> 00:32:36,166 and could detect signatures of life 773 00:32:36,166 --> 00:32:39,033 in the atmosphere, right? 774 00:32:39,033 --> 00:32:43,400 And this is actually something that's happening, right? 775 00:32:43,400 --> 00:32:46,866 These two have both been observed, right? 776 00:32:46,866 --> 00:32:49,766 This one, the results were announced last fall. 777 00:32:49,766 --> 00:32:52,000 This one, the results were announced last spring. 778 00:32:52,000 --> 00:32:53,800 Top one hasn't been looked at yet, 779 00:32:53,800 --> 00:32:55,733 but there's a lot of people putting in proposals. 780 00:32:55,733 --> 00:32:57,566 We're putting in proposals 781 00:32:57,566 --> 00:32:59,400 and getting time to look at these planets, 782 00:32:59,400 --> 00:33:01,100 and we're finding new ones 783 00:33:01,100 --> 00:33:03,266 to try and find life on these planets, 784 00:33:03,266 --> 00:33:07,400 and we think we have a pretty good shot if it's there. 785 00:33:07,400 --> 00:33:09,766 The really fun part is gonna be 786 00:33:09,766 --> 00:33:12,833 once we get something that we think might be life 787 00:33:12,833 --> 00:33:17,433 because I've been describing to you how we need to understand 788 00:33:17,433 --> 00:33:19,000 the biosignatures in the atmosphere: 789 00:33:19,000 --> 00:33:20,400 We need to look for water; 790 00:33:20,400 --> 00:33:23,466 we need to look for oxygen, maybe a little bit of methane-- 791 00:33:23,466 --> 00:33:27,333 and what's gonna happen if we do this successfully is, 792 00:33:27,333 --> 00:33:28,500 we're gonna get something 793 00:33:28,500 --> 00:33:29,900 that looks like an atmosphere like Earth, 794 00:33:29,900 --> 00:33:32,700 and then we're gonna have to figure out if all those gases 795 00:33:32,700 --> 00:33:34,133 and things we see in the atmosphere 796 00:33:34,133 --> 00:33:36,166 are produced by life or if they're produced 797 00:33:36,166 --> 00:33:39,266 by things like volcanoes or geologic processes. 798 00:33:39,266 --> 00:33:42,500 And figuring that out is gonna require not just astronomers 799 00:33:42,500 --> 00:33:44,933 and people who know how to operate JWST 800 00:33:44,933 --> 00:33:47,333 and know how to measure exoplanet atmospheres. 801 00:33:47,333 --> 00:33:49,100 We're gonna need planetary scientists. 802 00:33:49,100 --> 00:33:52,066 We're gonna need geologists, biologists, 803 00:33:52,066 --> 00:33:54,800 ocean scientists, everybody, right? 804 00:33:54,800 --> 00:33:57,600 All these other bits of the puzzle that we all need 805 00:33:57,600 --> 00:34:00,633 to get together and figure out what's going on, 806 00:34:00,633 --> 00:34:03,266 and that's the idea behind this thing 807 00:34:03,266 --> 00:34:06,533 called the Wisconsin Center for Origins Research, WiCOR, 808 00:34:06,533 --> 00:34:10,833 that is, hopefully, starting this fall. 809 00:34:10,833 --> 00:34:12,666 We're provisionally starting-- 810 00:34:12,666 --> 00:34:14,300 We're provisionally a center right now, 811 00:34:14,300 --> 00:34:16,166 but we're hopefully officially gonna be a center 812 00:34:16,166 --> 00:34:19,100 this coming fall that is specifically designed 813 00:34:19,100 --> 00:34:21,533 to do just that, to get all these different people together 814 00:34:21,533 --> 00:34:24,633 from all these different departments at UW-Madison 815 00:34:24,633 --> 00:34:26,833 to start talking and figure out 816 00:34:26,833 --> 00:34:28,566 how can we plan for detecting life 817 00:34:28,566 --> 00:34:30,633 and how can we design observations 818 00:34:30,633 --> 00:34:31,800 that are gonna do it? 819 00:34:31,800 --> 00:34:33,166 And once we've done it, 820 00:34:33,166 --> 00:34:35,666 how do we prove that it's life in a way that's convincing 821 00:34:35,666 --> 00:34:37,633 to the rest of the scientific community? 822 00:34:37,633 --> 00:34:40,366 And it's a project that's gonna be extremely difficult, 823 00:34:40,366 --> 00:34:43,000 and it's gonna require a lot of different people 824 00:34:43,000 --> 00:34:45,833 all working together, sharing their own specialized knowledge, 825 00:34:45,833 --> 00:34:47,633 but we think it can be done. 826 00:34:48,866 --> 00:34:50,033 Okay. 827 00:34:51,466 --> 00:34:55,800 I like this flowchart. 828 00:34:55,800 --> 00:34:58,300 Usually, actually, when I show this slide, 829 00:34:58,300 --> 00:35:00,133 I don't really have much to say here. 830 00:35:00,133 --> 00:35:01,633 I just sort of like the way 831 00:35:01,633 --> 00:35:04,500 it schematically lays out what's going on. 832 00:35:04,500 --> 00:35:07,200 It actually reflects a lot of my thinking on this as well. 833 00:35:07,200 --> 00:35:10,133 I will say, my particular favorite is that 834 00:35:10,133 --> 00:35:11,533 the successful detection of life 835 00:35:11,533 --> 00:35:14,500 is just labeled by "champagne," right? 836 00:35:14,500 --> 00:35:17,166 Right, this is the basic outline of what we need to do. 837 00:35:17,166 --> 00:35:18,866 We need to find planets. 838 00:35:18,866 --> 00:35:20,866 We need to figure out if they're like the Earth. 839 00:35:20,866 --> 00:35:23,266 We need to run through a bunch of tests in the atmosphere 840 00:35:23,266 --> 00:35:25,666 to see what's in it, and at the end of the day, 841 00:35:25,666 --> 00:35:28,166 hopefully, we'll work our way down to champagne 842 00:35:28,166 --> 00:35:30,833 and then have to start talking to the geologists 843 00:35:30,833 --> 00:35:32,366 and the oceanography people 844 00:35:32,366 --> 00:35:35,566 to figure out if this is actually feasible. 845 00:35:37,833 --> 00:35:43,300 Okay, so I'm gonna end with this picture again, right? 846 00:35:43,300 --> 00:35:47,133 So, as I mentioned at the start of the talk, 847 00:35:47,133 --> 00:35:50,133 you know, people have been thinking about 848 00:35:50,133 --> 00:35:52,166 is there life elsewhere in the universe, right? 849 00:35:52,166 --> 00:35:55,100 The question "Is there a planet like the Earth somewhere else?" 850 00:35:55,100 --> 00:35:58,666 for at least 2,500 years, right, over 2,000 years, 851 00:35:58,666 --> 00:36:00,733 probably more than that, right? 852 00:36:00,733 --> 00:36:02,266 That's a pretty-- 853 00:36:02,266 --> 00:36:03,766 I can imagine somebody asked that question 854 00:36:03,766 --> 00:36:06,233 a very long time ago. 855 00:36:06,233 --> 00:36:08,033 And even in the astronomical community, 856 00:36:08,033 --> 00:36:11,233 in exoplanets, people have spent the last three decades, 857 00:36:11,233 --> 00:36:12,900 even since we knew about exoplanets, 858 00:36:12,900 --> 00:36:14,966 looking for planets like the Earth, 859 00:36:14,966 --> 00:36:16,766 and we're starting to find them. 860 00:36:18,600 --> 00:36:21,900 And one of the big revolutions in astronomy is, 861 00:36:21,900 --> 00:36:24,200 the search for biosignatures and the search for life 862 00:36:24,200 --> 00:36:27,100 has progressed from something that, you know, 863 00:36:27,100 --> 00:36:29,933 nobody really takes seriously to something that 864 00:36:29,933 --> 00:36:33,600 a lot of people are trying very hard to do successfully, 865 00:36:33,600 --> 00:36:38,000 and it's an incredibly exciting time 866 00:36:38,000 --> 00:36:39,533 to be a part of astronomy, right, 867 00:36:39,533 --> 00:36:42,533 'cause, like, the stuff that we are doing at UW, 868 00:36:42,533 --> 00:36:44,266 you know, we're assembling this team 869 00:36:44,266 --> 00:36:46,200 that's gonna hopefully do this. 870 00:36:46,200 --> 00:36:49,033 We're observing tonight, like I said, to try and find 871 00:36:49,033 --> 00:36:51,833 new planets that we can look at with instruments 872 00:36:51,833 --> 00:36:55,233 like the James Webb to try and find life elsewhere. 873 00:36:55,233 --> 00:36:56,800 Like, the hunt is on, 874 00:36:56,800 --> 00:36:59,166 and it's happening now as we speak, right? 875 00:36:59,166 --> 00:37:00,633 Like, people are doing it. 876 00:37:00,633 --> 00:37:03,500 This isn't some future thing maybe in a couple of years, 877 00:37:03,500 --> 00:37:05,833 we could think about, you know, 878 00:37:05,833 --> 00:37:07,400 looking for life on other planets. 879 00:37:07,400 --> 00:37:09,966 People are actively searching right now, 880 00:37:09,966 --> 00:37:11,466 and if it's out there 881 00:37:11,466 --> 00:37:13,966 and if it's on some of these big, sort of, hycean planets, 882 00:37:13,966 --> 00:37:16,166 I think we have a pretty good shot of doing it 883 00:37:16,166 --> 00:37:17,400 in the next 10 years. 884 00:37:17,400 --> 00:37:21,600 Probably earlier than that-- by 2030, I bet, right? 885 00:37:21,600 --> 00:37:24,666 That means that we are right on the edge of answering 886 00:37:24,666 --> 00:37:29,233 a question that people have thought of for 2,500 years 887 00:37:29,233 --> 00:37:31,400 and wondered about the answer for. 888 00:37:31,400 --> 00:37:33,666 And so it's a very exciting time to be in astronomy, 889 00:37:33,666 --> 00:37:35,866 and it's a very exciting time to think about finally knowing 890 00:37:35,866 --> 00:37:38,400 the answer to that question after over two millennia 891 00:37:38,400 --> 00:37:41,566 of people wondering about it, and it's, you know, 892 00:37:41,566 --> 00:37:45,100 it's why I get excited about going in to work in the morning. 893 00:37:45,100 --> 00:37:47,033 It's also why I like giving these talks, right, 894 00:37:47,033 --> 00:37:49,700 to tell you guys about that and hopefully get you excited 895 00:37:49,700 --> 00:37:54,500 about how really close we are to actually doing this. 896 00:37:54,500 --> 00:37:58,500 You know, I said it's gonna be very hard, right? 897 00:37:58,500 --> 00:38:00,900 It's very difficult observations. 898 00:38:00,900 --> 00:38:03,166 It's a very complicated analysis problem, 899 00:38:03,166 --> 00:38:05,766 and it's gonna be a pretty subtle chain of logic 900 00:38:05,766 --> 00:38:07,866 that's gonna get us there, 901 00:38:07,866 --> 00:38:09,733 but, you know, I think it's gonna be 902 00:38:09,733 --> 00:38:15,966 probably one of the most complicated and difficult 903 00:38:15,966 --> 00:38:19,500 but probably greatest, you know, scientific endeavor 904 00:38:19,500 --> 00:38:23,600 that astronomy has done for the last couple hundred years. 905 00:38:23,600 --> 00:38:25,966 So, hopefully, we're gonna get to champagne 906 00:38:25,966 --> 00:38:28,833 in the next couple of years, and if we do, I will come back 907 00:38:28,833 --> 00:38:32,500 and tell you guys all about it in another Badger Talk. 908 00:38:32,500 --> 00:38:34,900 So thank you, and I'll take questions. 909 00:38:34,900 --> 00:38:37,200 [audience applauding] 910 00:38:41,933 --> 00:38:43,666 Uh, yeah? 911 00:38:43,666 --> 00:38:46,400 - Audience Member 1: Is it possible that some of the moons, 912 00:38:46,400 --> 00:38:50,633 both within our solar system and outside, could contain life? 913 00:38:50,633 --> 00:38:52,833 - Right, so is it possible that some of the moons 914 00:38:52,833 --> 00:38:54,966 in our solar system or outside could contain life? 915 00:38:54,966 --> 00:38:59,500 Yes, and, actually, the planetary science community 916 00:38:59,500 --> 00:39:02,566 is very excited about going out 917 00:39:02,566 --> 00:39:05,566 to the moons of Jupiter and Saturn, as well. 918 00:39:05,566 --> 00:39:08,966 So there's one mission called Europa Clipper 919 00:39:08,966 --> 00:39:11,600 that is launching in six months that's gonna travel 920 00:39:11,600 --> 00:39:13,966 to Jupiter's moon Europa, and Europa is very exciting 921 00:39:13,966 --> 00:39:18,433 'cause it's covered in a surface of ice, right? 922 00:39:18,433 --> 00:39:22,033 It's cold enough that ice on Europa is like rock on Earth, 923 00:39:22,033 --> 00:39:24,433 so the surface is solid ice, solid water, 924 00:39:24,433 --> 00:39:26,533 and then the mantle, what we have for lava, 925 00:39:26,533 --> 00:39:29,200 is just liquid water, so it's liquid water ocean, 926 00:39:29,200 --> 00:39:31,366 and there seems to be volcanoes underneath. 927 00:39:31,366 --> 00:39:34,733 We know that 'cause we can see ice volcanoes on the surface, 928 00:39:34,733 --> 00:39:36,633 so it seems like it's a liquid water ocean 929 00:39:36,633 --> 00:39:39,766 and there's volcanoes adding energy into that system, 930 00:39:39,766 --> 00:39:42,266 and so it's very possible there's life there, 931 00:39:42,266 --> 00:39:44,533 and so there's Europa, there's Enceladus, 932 00:39:44,533 --> 00:39:46,666 which is around Saturn, is another exciting one, 933 00:39:46,666 --> 00:39:48,900 and Titan around Saturn is in many ways 934 00:39:48,900 --> 00:39:50,833 actually pretty similar to early Earth 935 00:39:50,833 --> 00:39:53,866 before life evolved, or Archean Earth, actually. 936 00:39:53,866 --> 00:39:55,833 That's very early life on Earth, 937 00:39:55,833 --> 00:39:58,066 when we had a lot of methane in our atmosphere, 938 00:39:58,066 --> 00:40:01,766 and so all three of those, people are spending 939 00:40:01,766 --> 00:40:03,933 a lot of time thinking about and developing missions for 940 00:40:03,933 --> 00:40:06,000 to try and find life, 941 00:40:06,000 --> 00:40:09,000 and people have been searching for moons 942 00:40:09,000 --> 00:40:11,766 outside the solar system, moons around exoplanets, 943 00:40:11,766 --> 00:40:14,100 and there's been a couple of tentative detections, 944 00:40:14,100 --> 00:40:15,600 but nothing quite yet. 945 00:40:15,600 --> 00:40:17,200 But people are thinking about that as well. 946 00:40:17,200 --> 00:40:19,766 So, yeah, moons in the solar system, people are-- 947 00:40:19,766 --> 00:40:21,766 the planetary science community is thinking about that a lot 948 00:40:21,766 --> 00:40:23,566 and actually getting stuff out there 949 00:40:23,566 --> 00:40:26,366 'cause Europa Clipper will launch soon. 950 00:40:26,366 --> 00:40:27,866 Uh, yeah? 951 00:40:27,866 --> 00:40:30,366 - Audience Member 2: What future telescopes are being planned 952 00:40:30,366 --> 00:40:32,300 that you can get a closer look at these? 953 00:40:32,300 --> 00:40:34,433 Is there any in the works right now? 954 00:40:34,433 --> 00:40:37,133 - Yeah, so what future telescopes are being planned? 955 00:40:37,133 --> 00:40:40,733 So the next big NASA telescope mission 956 00:40:40,733 --> 00:40:42,766 will be something called Roman, 957 00:40:42,766 --> 00:40:45,600 which is launching in '26 currently. 958 00:40:45,600 --> 00:40:50,833 That's more of a exoplanet detection and population survey 959 00:40:50,833 --> 00:40:52,700 than a characterization mission. 960 00:40:52,700 --> 00:40:55,566 Probably, there are a couple of other missions 961 00:40:55,566 --> 00:40:57,066 that are gonna launch that will do 962 00:40:57,066 --> 00:41:00,400 exoplanet atmospheric characterization, 963 00:41:00,400 --> 00:41:03,933 but they're not gonna greatly exceed JWST's capability. 964 00:41:03,933 --> 00:41:06,100 The next big thing that everybody is thinking about 965 00:41:06,100 --> 00:41:07,900 is a mission that right now is called 966 00:41:07,900 --> 00:41:14,033 the Habitable Worlds Observatory that, you know, 967 00:41:14,033 --> 00:41:17,533 is currently scheduled for 2035 for launch, 968 00:41:17,533 --> 00:41:19,933 but put your own handicap on that. 969 00:41:19,933 --> 00:41:22,566 It's probably later than that, but that is the idea. 970 00:41:22,566 --> 00:41:25,133 We're gonna put a very large, you know, eight-meter mirror 971 00:41:25,133 --> 00:41:27,533 in space, and that will be, in principle, able 972 00:41:27,533 --> 00:41:29,500 to directly image planets like the Earth 973 00:41:29,500 --> 00:41:32,500 and actually measure the atmospheres directly. 974 00:41:32,500 --> 00:41:34,300 We don't need to do it indirectly by waiting 975 00:41:34,300 --> 00:41:37,133 for planets to pass in front of a star. 976 00:41:37,133 --> 00:41:40,566 So Habitable Worlds Observatory, HabWorlds, 977 00:41:40,566 --> 00:41:42,800 if it launches, should be able to do this. 978 00:41:42,800 --> 00:41:44,466 But that's another good point, right? 979 00:41:44,466 --> 00:41:46,400 HabWorlds, like, is just-- 980 00:41:46,400 --> 00:41:48,966 It's just an engineering problem right now, right? 981 00:41:48,966 --> 00:41:51,500 It's an engineering, and it's a "convince the Congress 982 00:41:51,500 --> 00:41:54,566 to give NASA enough money to build it" problem, right? 983 00:41:54,566 --> 00:41:57,400 We could do this very quickly if we wanted to. 984 00:41:57,400 --> 00:41:59,600 It's just, we need to do a couple of engineering checks 985 00:41:59,600 --> 00:42:00,833 and stuff, right? 986 00:42:00,833 --> 00:42:02,200 This is no longer science fiction. 987 00:42:02,200 --> 00:42:03,600 This is like, "Let's go to Congress 988 00:42:03,600 --> 00:42:05,400 and ask for money to do it." 989 00:42:05,400 --> 00:42:07,800 - Audience Member 3: You said if all life on Earth died... 990 00:42:07,800 --> 00:42:08,966 - Mm-hmm. 991 00:42:08,966 --> 00:42:10,733 - That within a couple thousand years, 992 00:42:10,733 --> 00:42:12,333 the oxygen and the atmosphere would be gone. 993 00:42:12,333 --> 00:42:13,533 - Thomas: Yeah. - Why? 994 00:42:13,533 --> 00:42:14,933 What would it make it go away? 995 00:42:14,933 --> 00:42:17,666 - Right, so why does the oxygen disappear if life disappears? 996 00:42:17,666 --> 00:42:20,033 So oxygen, I mean, it's sort of the reason why 997 00:42:20,033 --> 00:42:21,366 it's so fundamental to life, 998 00:42:21,366 --> 00:42:24,766 'cause oxygen is incredibly reactive with stuff. 999 00:42:24,766 --> 00:42:29,366 So oxygen, it will disappear into rocks through rust. 1000 00:42:29,366 --> 00:42:34,533 It will, you know, go into-- 1001 00:42:34,533 --> 00:42:36,833 Sort of like acid rain, it will go into the water. 1002 00:42:36,833 --> 00:42:40,366 And it'll go into the seafloor in, like, lime or something. 1003 00:42:40,366 --> 00:42:43,733 It just gets absorbed into rocks and water 1004 00:42:43,733 --> 00:42:46,566 and geologic processes very quickly. 1005 00:42:46,566 --> 00:42:48,766 - Audience Member 3: So it's not that it would be-- 1006 00:42:48,766 --> 00:42:51,166 like, just drift away or be blown away by the solar wind. 1007 00:42:51,166 --> 00:42:53,366 - Oh, no, yeah, so it doesn't escape from the Earth. 1008 00:42:53,366 --> 00:42:54,566 It doesn't-- It still stays here. 1009 00:42:54,566 --> 00:42:55,966 Just, it's gonna go into the rocks. 1010 00:42:55,966 --> 00:42:57,566 We're gonna turn into Mars, effectively. 1011 00:42:57,566 --> 00:42:59,466 We're gonna turn into a rusty red planet 1012 00:42:59,466 --> 00:43:03,066 if all the life disappeared, yeah. 1013 00:43:03,066 --> 00:43:04,233 Yeah? 1014 00:43:04,233 --> 00:43:05,833 - Audience Member 4: So how many times 1015 00:43:05,833 --> 00:43:07,233 do you have to observe an exoplanet 1016 00:43:07,233 --> 00:43:11,000 before you actually confirm that you think it's an exoplanet, 1017 00:43:11,000 --> 00:43:14,033 and how do you track its location so that in the future, 1018 00:43:14,033 --> 00:43:16,766 you can have the Webb check back? 1019 00:43:16,766 --> 00:43:18,700 - Right, so how many times 1020 00:43:18,700 --> 00:43:21,166 do you have to look at an exoplanet to confirm it, 1021 00:43:21,166 --> 00:43:24,100 and then how do we track it so we can look at it later? 1022 00:43:24,100 --> 00:43:28,900 So confirmation observations are-- 1023 00:43:30,200 --> 00:43:33,900 So actually, the planets that I'm working on 1024 00:43:33,900 --> 00:43:35,966 with a student right now are probably a good way 1025 00:43:35,966 --> 00:43:38,900 to explain what the process is. 1026 00:43:38,900 --> 00:43:41,333 So there's a NASA mission up right now called TESS, 1027 00:43:41,333 --> 00:43:44,166 which is just scanning the sky for new exoplanets, 1028 00:43:44,166 --> 00:43:45,566 and so it finds something that looks 1029 00:43:45,566 --> 00:43:46,733 like a transiting exoplanet, 1030 00:43:46,733 --> 00:43:48,533 like a planet going in front of its star. 1031 00:43:48,533 --> 00:43:50,500 It's measuring the brightness of all the stars, 1032 00:43:50,500 --> 00:43:52,566 but one of the problems is that there's, 1033 00:43:52,566 --> 00:43:54,966 for lack of a better word, a lot of things that go 1034 00:43:54,966 --> 00:43:57,733 bump in the night that look like planets but are not. 1035 00:43:57,733 --> 00:44:01,066 There's a lot of things like stars and other, you know, 1036 00:44:01,066 --> 00:44:04,000 things that aren't planets that can mimic those transit signals. 1037 00:44:04,000 --> 00:44:06,800 So we get a lot of candidates and then we have to refine that, 1038 00:44:06,800 --> 00:44:11,066 so we look at it with telescopes like WIYN, right, 1039 00:44:11,066 --> 00:44:13,466 that we have in Kitt Peak to look for the star moving, 1040 00:44:13,466 --> 00:44:15,466 and if we see the star moving, that tells us 1041 00:44:15,466 --> 00:44:18,033 the mass of the object, and so we get a good mass. 1042 00:44:18,033 --> 00:44:21,033 Usually, we'll look at it with bigger telescopes on the ground 1043 00:44:21,033 --> 00:44:22,633 to make sure it's happening on the star 1044 00:44:22,633 --> 00:44:25,033 we think it's happening on. 1045 00:44:25,033 --> 00:44:27,033 And so that's most of the confirmation process. 1046 00:44:27,033 --> 00:44:29,433 If you can see the planet go in front of the star, 1047 00:44:29,433 --> 00:44:32,166 if you can measure the mass from the star 1048 00:44:32,166 --> 00:44:35,300 wobbling back and forth, and if you can demonstrate 1049 00:44:35,300 --> 00:44:38,300 that there's no nearby star that you're getting confused with, 1050 00:44:38,300 --> 00:44:40,266 then you're pretty much there, 1051 00:44:40,266 --> 00:44:42,966 and you know there's a planet around that star. 1052 00:44:42,966 --> 00:44:47,866 And as a part of that, we generate what's called, 1053 00:44:47,866 --> 00:44:50,733 you know, an ephemeris for the planet, you know, 1054 00:44:50,733 --> 00:44:53,566 a prediction for when transits will occur. 1055 00:44:53,566 --> 00:44:55,233 And for the first couple of years, 1056 00:44:55,233 --> 00:44:57,566 those are probably good to a couple of minutes, 1057 00:44:57,566 --> 00:45:00,166 but over time, those will drift, and some of the planets 1058 00:45:00,166 --> 00:45:01,833 that were discovered 10 years ago, 1059 00:45:01,833 --> 00:45:03,266 we don't actually know the transits 1060 00:45:03,266 --> 00:45:05,966 to better than half an hour or maybe even hours. 1061 00:45:05,966 --> 00:45:09,600 So for JWST observations, you need to know it to minutes, 1062 00:45:09,600 --> 00:45:13,100 and so there's actually efforts that a lot of people work on, 1063 00:45:13,100 --> 00:45:15,300 that a fair number of people work on to go back 1064 00:45:15,300 --> 00:45:18,600 to older planets and look at them again to get more, 1065 00:45:18,600 --> 00:45:20,900 sort of reset that drift on the clock 1066 00:45:20,900 --> 00:45:22,933 and figure out when it's gonna happen 1067 00:45:22,933 --> 00:45:27,033 to refine the ephemerides so we don't lose 'em 1068 00:45:27,033 --> 00:45:29,466 and we still know exactly when they're going to transit. 1069 00:45:29,466 --> 00:45:34,000 So it's a lot of people working to do both parts of that. 1070 00:45:36,366 --> 00:45:37,733 Uh, yeah? 1071 00:45:37,733 --> 00:45:40,400 - Audience Member 5: In the red ring on the map 1072 00:45:40,400 --> 00:45:44,533 of the Milky Way, like, where you found the planets, 1073 00:45:44,533 --> 00:45:47,533 how far away are we talking about 1074 00:45:47,533 --> 00:45:48,900 as far as, like, light-years, 1075 00:45:48,900 --> 00:45:51,700 and how far back in time are we looking? 1076 00:45:51,700 --> 00:45:55,333 - Right, so how big is that red ring in light-years, 1077 00:45:55,333 --> 00:45:57,733 and how far away are we looking? 1078 00:45:57,733 --> 00:46:01,533 So most of the planets that we know about are probably-- 1079 00:46:01,533 --> 00:46:05,200 I'm doing a conversion in my head 1080 00:46:05,200 --> 00:46:07,966 'cause most of us, a lot of astronomers 1081 00:46:07,966 --> 00:46:09,833 use parsecs instead of light-years. 1082 00:46:09,833 --> 00:46:12,000 Yeah, if you guys ever wanna be cool 1083 00:46:12,000 --> 00:46:13,300 at an astronomy party-- 1084 00:46:13,300 --> 00:46:15,500 I don't know why you'd be going to an astronomy party, 1085 00:46:15,500 --> 00:46:20,033 but if you want an invite, I think Mary has my email. 1086 00:46:20,033 --> 00:46:22,033 Yeah, talk about things in parsecs. 1087 00:46:22,033 --> 00:46:24,700 That's how you know you're on the in-crowd. 1088 00:46:24,700 --> 00:46:30,600 So probably out to about 500 light-years, I'd say, 1089 00:46:30,600 --> 00:46:33,100 most of the detections, which means that most of the planets 1090 00:46:33,100 --> 00:46:36,600 we're seeing only about 500 years back in time, 1091 00:46:36,600 --> 00:46:39,933 which, on an astronomical scale, is pretty small. 1092 00:46:39,933 --> 00:46:41,733 Most of them are actually even closer than that, 1093 00:46:41,733 --> 00:46:44,133 probably within 50-ish light years, 1094 00:46:44,133 --> 00:46:46,333 so not very far away. 1095 00:46:46,333 --> 00:46:48,900 The time scales here, there's one planet we know of, 1096 00:46:48,900 --> 00:46:50,900 actually, that's decaying onto its star. 1097 00:46:50,900 --> 00:46:53,533 Like, the orbit is shrinking and it's falling onto its star, 1098 00:46:53,533 --> 00:46:55,066 and it's happening incredibly fast, 1099 00:46:55,066 --> 00:46:56,600 which means in 3 million years, 1100 00:46:56,600 --> 00:46:58,633 it's gonna hit the surface of the star. 1101 00:46:58,633 --> 00:47:02,400 So 3 million years is incredibly fast for astronomers. 1102 00:47:02,400 --> 00:47:03,566 Yeah? 1103 00:47:03,566 --> 00:47:05,833 - Audience Member 6: So how big is it in parsecs? 1104 00:47:05,833 --> 00:47:09,966 - It's probably about 200 parsecs, 300 parsecs. 1105 00:47:09,966 --> 00:47:12,666 I guess that's a little bit more than 500 light-years. 1106 00:47:12,666 --> 00:47:16,266 Yeah, about 200 parsecs, I'd say. 1107 00:47:16,266 --> 00:47:19,100 There's stuff much further out, but most of them are centered 1108 00:47:19,100 --> 00:47:21,633 closer than that. 1109 00:47:21,633 --> 00:47:22,800 Yeah? 1110 00:47:22,800 --> 00:47:24,800 - Audience Member 7: Is AI going to be able 1111 00:47:24,800 --> 00:47:26,633 to help you in your search? 1112 00:47:26,633 --> 00:47:29,966 - Is AI gonna be helpful in this search? 1113 00:47:29,966 --> 00:47:32,166 It's funny you ask that 'cause I actually was just part 1114 00:47:32,166 --> 00:47:38,100 of a very big proposal to do just that. 1115 00:47:38,100 --> 00:47:39,833 So there's a bunch of ways. 1116 00:47:39,833 --> 00:47:42,333 I think the thing that got me really excited-- 1117 00:47:42,333 --> 00:47:46,066 and this maybe is a little inside baseball-- 1118 00:47:46,066 --> 00:47:49,166 but one of the fundamental limitations we have 1119 00:47:49,166 --> 00:47:50,633 is that we have to compute-- 1120 00:47:50,633 --> 00:47:52,000 We get the observations 1121 00:47:52,000 --> 00:47:53,800 and then we need to compute atmosphere models, right? 1122 00:47:53,800 --> 00:47:55,600 We get the data, but to actually figure out 1123 00:47:55,600 --> 00:47:58,066 what's in the atmosphere, we need to compute models. 1124 00:47:58,066 --> 00:47:59,800 We need to run these complicated-- 1125 00:47:59,800 --> 00:48:02,766 We effectively need to run a weather model on a computer, 1126 00:48:02,766 --> 00:48:04,600 and we need to do that a million times 1127 00:48:04,600 --> 00:48:07,100 to try and run all these different parameters. 1128 00:48:07,100 --> 00:48:10,000 And so the sorts of systems I'm working on 1129 00:48:10,000 --> 00:48:12,966 typically take one to two to three weeks, 1130 00:48:12,966 --> 00:48:15,800 two to three weeks to run on a computer. 1131 00:48:15,800 --> 00:48:18,566 And that's on, like, a supercomputer-- 1132 00:48:18,566 --> 00:48:22,233 it's actually at Arizona State-- but it takes a long time to run, 1133 00:48:22,233 --> 00:48:25,033 and so one of the things we're particularly looking at 1134 00:48:25,033 --> 00:48:27,466 is how can we use AI to speed up that process 1135 00:48:27,466 --> 00:48:29,666 'cause that's only a one-dimensional model. 1136 00:48:29,666 --> 00:48:33,433 We're not doing any sort of latitude/longitude modeling. 1137 00:48:33,433 --> 00:48:35,366 We're just doing straight up and down, 1138 00:48:35,366 --> 00:48:37,966 and running it out to a 3-D model, like we would have 1139 00:48:37,966 --> 00:48:41,733 on the Earth, would take-- you know, it would take months 1140 00:48:41,733 --> 00:48:45,400 to run one of these things, and we'd need to run 10,000. 1141 00:48:45,400 --> 00:48:50,000 So one thing that I'm interested in looking at 1142 00:48:50,000 --> 00:48:52,633 is how do we use AI machine learning 1143 00:48:52,633 --> 00:48:55,966 to try and speed that up and get it to run faster, 1144 00:48:55,966 --> 00:48:58,966 but right now, that's just an idea. 1145 00:48:58,966 --> 00:49:01,200 Nobody's actually done it yet. 1146 00:49:02,966 --> 00:49:04,133 Yeah? 1147 00:49:04,133 --> 00:49:06,700 - Audience Member 8: Do you anticipate getting 1148 00:49:06,700 --> 00:49:14,600 beyond the infrared look and closer to the microwave look 1149 00:49:14,600 --> 00:49:18,833 as far as the radio waves? 1150 00:49:18,833 --> 00:49:20,700 - Yeah, so are we thinking about moving 1151 00:49:20,700 --> 00:49:22,733 into, like, microwave or radio waves? 1152 00:49:22,733 --> 00:49:25,800 So there are people, actually, 1153 00:49:25,800 --> 00:49:28,133 who do that now, but they don't-- 1154 00:49:28,133 --> 00:49:32,100 They use radio and microwave and millimeter waves to-- 1155 00:49:32,100 --> 00:49:33,666 They don't look at planets, 1156 00:49:33,666 --> 00:49:35,566 but they actually look at protoplanetary disks, 1157 00:49:35,566 --> 00:49:38,933 so the stuff that forms planets, and there are beautiful images 1158 00:49:38,933 --> 00:49:41,600 taken by an observatory called ALMA 1159 00:49:41,600 --> 00:49:43,533 which just started operating a couple years ago 1160 00:49:43,533 --> 00:49:47,800 in northern Chile to observe protoplanetary disks, 1161 00:49:47,800 --> 00:49:50,033 and you can see-- Actually, it's amazing. 1162 00:49:50,033 --> 00:49:53,533 Guys, just Google search, like, "ALMA protoplanetary disk." 1163 00:49:53,533 --> 00:49:55,266 Remember that and Google search it 1164 00:49:55,266 --> 00:49:58,066 'cause it's, there are these disks of material, 1165 00:49:58,066 --> 00:49:59,666 and then you can see there are rings. 1166 00:49:59,666 --> 00:50:01,066 There are gaps in the disks. 1167 00:50:01,066 --> 00:50:03,066 Those are planets that are forming that have sucked 1168 00:50:03,066 --> 00:50:05,266 all that material and that ring onto them. 1169 00:50:05,266 --> 00:50:06,433 Like, that's Jupiter 1170 00:50:06,433 --> 00:50:07,833 that's pulled all that material onto it. 1171 00:50:07,833 --> 00:50:09,033 And you can't see the planet, 1172 00:50:09,033 --> 00:50:10,633 but you can see all the gas missing 1173 00:50:10,633 --> 00:50:12,433 where the planet must be forming. 1174 00:50:12,433 --> 00:50:14,066 And it's these amazing images-- 1175 00:50:14,066 --> 00:50:16,833 There's a woman, actually here at UW, 1176 00:50:16,833 --> 00:50:20,833 Coco Zhang, who does this, so that's a big part 1177 00:50:20,833 --> 00:50:22,900 of understanding planet-formation processes. 1178 00:50:22,900 --> 00:50:25,100 That's a whole 'nother thing that I could talk forever about, 1179 00:50:25,100 --> 00:50:26,966 is trying to figure that out, but, yeah, 1180 00:50:26,966 --> 00:50:28,966 that's a big part of it as well. 1181 00:50:28,966 --> 00:50:32,433 All right, oh, we got one more, yeah? 1182 00:50:32,433 --> 00:50:33,833 - Audience Member 9: I was wondering, 1183 00:50:33,833 --> 00:50:35,833 on the original red disk 1184 00:50:35,833 --> 00:50:40,166 that it said, out of the 5,761 exoplanets 1185 00:50:40,166 --> 00:50:44,000 that have been discovered, what is the percentage 1186 00:50:44,000 --> 00:50:47,133 of systems that you scanned that actually come up back 1187 00:50:47,133 --> 00:50:50,000 and have an exoplanet within there? 1188 00:50:50,000 --> 00:50:52,300 - Oh, so, yeah, so how many stars 1189 00:50:52,300 --> 00:50:54,500 do we need to look at before we find a planet? 1190 00:50:54,500 --> 00:50:59,800 Yeah, so that was my PhD thesis, was finding exoplanets 1191 00:50:59,800 --> 00:51:02,600 and running a planet-detection survey. 1192 00:51:02,600 --> 00:51:04,333 That's why I'm particularly bitter 1193 00:51:04,333 --> 00:51:06,966 about not being able to name them after myself, 1194 00:51:06,966 --> 00:51:09,633 because it was specifically my PhD-- 1195 00:51:09,633 --> 00:51:11,833 I actually asked my PhD advisor if we could do this, 1196 00:51:11,833 --> 00:51:13,300 and he just was, like, 1197 00:51:13,300 --> 00:51:16,366 "Under no circumstances can you name this after yourself." 1198 00:51:16,366 --> 00:51:19,366 So the answer is, we probably looked at... 1199 00:51:23,400 --> 00:51:27,033 We looked at about 10,000 stars before we found one. 1200 00:51:29,233 --> 00:51:33,500 But, right, but there's a lot of what are called 1201 00:51:33,500 --> 00:51:35,933 observational biases that go into that, right? 1202 00:51:35,933 --> 00:51:39,300 So that doesn't mean that one star out of 10,000 has a planet. 1203 00:51:39,300 --> 00:51:42,533 It just means it's very hard to find transiting planets 1204 00:51:42,533 --> 00:51:44,233 'cause we were looking for very big ones, 1205 00:51:44,233 --> 00:51:45,633 which are pretty rare, 1206 00:51:45,633 --> 00:51:47,566 very close-in ones, which are pretty rare, 1207 00:51:47,566 --> 00:51:49,366 and they needed to go right across the star, 1208 00:51:49,366 --> 00:51:51,566 which is pretty rare, right, so there's a lot of things 1209 00:51:51,566 --> 00:51:53,500 working against us when we do that search. 1210 00:51:53,500 --> 00:51:56,033 When people have tried to correct for that and say, 1211 00:51:56,033 --> 00:51:58,500 "Okay, we saw one out of 10,000, but, you know, 1212 00:51:58,500 --> 00:52:00,166 "we're only gonna see one out of ten 1213 00:52:00,166 --> 00:52:02,700 just because of the angle probabilities," 1214 00:52:02,700 --> 00:52:04,600 what's the actual rate? 1215 00:52:04,600 --> 00:52:08,966 Our actual guess for, say, how many habitable, 1216 00:52:08,966 --> 00:52:12,066 Earth-like planets are around an average star, 1217 00:52:12,066 --> 00:52:16,966 the current best guess is about one-half to two, 1218 00:52:16,966 --> 00:52:21,566 meaning that we think that, on average, 1219 00:52:21,566 --> 00:52:24,500 every single star like the Sun has a planet like the Earth 1220 00:52:24,500 --> 00:52:27,166 pretty close to its habitable zone, right? 1221 00:52:27,166 --> 00:52:29,466 It seems like planet formation happens, 1222 00:52:29,466 --> 00:52:31,066 and it happens all the time, 1223 00:52:31,066 --> 00:52:34,200 and it goes, and it makes a lot of planets around most stars. 1224 00:52:34,200 --> 00:52:38,333 So it's hard to find them, but that's sort of because 1225 00:52:38,333 --> 00:52:41,066 they're hard to find, not because they're rare. 1226 00:52:44,566 --> 00:52:46,566 - Audience Member 10: What would make that job easier? 1227 00:52:46,566 --> 00:52:48,133 - What would make that job easier? 1228 00:52:49,933 --> 00:52:53,866 Uh... bigger telescopes. 1229 00:52:53,866 --> 00:52:56,066 Well, no, actually, you know what would make the jobs easier? 1230 00:52:56,066 --> 00:53:02,900 If the stars cooperated, 'cause, man, let me tell you, 1231 00:53:02,900 --> 00:53:07,000 like, the Sun, so to detect the Earth around the Sun, 1232 00:53:07,000 --> 00:53:09,833 the velocity you're measuring is about this fast, right? 1233 00:53:09,833 --> 00:53:12,333 I am walking at about two meters per second, 1234 00:53:12,333 --> 00:53:13,766 one meter per second. 1235 00:53:13,766 --> 00:53:16,766 That's about how much the Earth makes the Sun move in speed, 1236 00:53:16,766 --> 00:53:18,400 but you're measuring this speed 1237 00:53:18,400 --> 00:53:20,566 over the course of a year, right? 1238 00:53:20,566 --> 00:53:24,166 The surface of the Sun is burbling all the time. 1239 00:53:24,166 --> 00:53:25,900 It's just sort of flexing a little bit 1240 00:53:25,900 --> 00:53:28,600 from solar flares and all sorts of things, right, 1241 00:53:28,600 --> 00:53:32,400 and the Sun is doing its own, like, processes inside it. 1242 00:53:32,400 --> 00:53:34,400 And so the surface is moving, and you can imagine 1243 00:53:34,400 --> 00:53:36,933 that measuring the whole Sun moving at this speed 1244 00:53:36,933 --> 00:53:40,233 is pretty difficult if the entire surface is just flexing 1245 00:53:40,233 --> 00:53:42,733 and wringing and bending underneath you. 1246 00:53:42,733 --> 00:53:45,566 So if I could have anything in the world, 1247 00:53:45,566 --> 00:53:48,366 I would tell the stars to just stand still 1248 00:53:48,366 --> 00:53:51,766 for, like, two years so we can measure them exactly, 1249 00:53:51,766 --> 00:53:54,566 and then if we could figure that out, 1250 00:53:54,566 --> 00:53:56,466 then we could do it, and, actually, 1251 00:53:56,466 --> 00:53:58,333 the sort of less joking answer to that is, 1252 00:53:58,333 --> 00:54:00,133 there's actually a lot of people working on ways 1253 00:54:00,133 --> 00:54:04,166 to try and, like, separate those two signals 1254 00:54:04,166 --> 00:54:06,166 and get down to the level where we can measure 1255 00:54:06,166 --> 00:54:07,566 a planet like the Earth, 1256 00:54:07,566 --> 00:54:10,600 but it's a difficult problem to try and separate that out. 1257 00:54:12,933 --> 00:54:14,566 Yeah? 1258 00:54:14,566 --> 00:54:16,066 - Audience Member 11: When you actually 1259 00:54:16,066 --> 00:54:18,033 designed the camera... - Mm-hmm, yeah. 1260 00:54:18,033 --> 00:54:19,666 Well, helped design, yeah. 1261 00:54:19,666 --> 00:54:22,066 - Audience Member 11: Did it have a lens cap on it? 1262 00:54:22,066 --> 00:54:23,666 - Did the camera have a lens cap? 1263 00:54:23,666 --> 00:54:25,766 It did not, no. 1264 00:54:25,766 --> 00:54:27,566 Actually, the thing that was gonna really get us 1265 00:54:27,566 --> 00:54:29,866 was the sun shield on Webb 1266 00:54:29,866 --> 00:54:33,600 because the whole thing, it needs to deploy out. 1267 00:54:33,600 --> 00:54:34,866 Well, I can't have-- 1268 00:54:34,866 --> 00:54:36,866 If you look at it, a picture, there's the mirrors, 1269 00:54:36,866 --> 00:54:38,066 and underneath that, there's this big-- 1270 00:54:38,066 --> 00:54:39,900 it's almost a tennis court-size thing, 1271 00:54:39,900 --> 00:54:41,233 and that's what shields it. 1272 00:54:41,233 --> 00:54:43,166 All the cameras need to be kept very cool, 1273 00:54:43,166 --> 00:54:45,533 like -200 degrees. 1274 00:54:45,533 --> 00:54:47,333 And so if the Sun is shining on it, 1275 00:54:47,333 --> 00:54:48,700 you can't keep it that way, 1276 00:54:48,700 --> 00:54:51,100 so the sun shield is there to block out all the sunlight, 1277 00:54:51,100 --> 00:54:53,300 but the problem is, the sun shield is very thin Mylar 1278 00:54:53,300 --> 00:54:54,466 that rips very easily. 1279 00:54:54,466 --> 00:54:56,300 It's designed to be deployed. 1280 00:54:56,300 --> 00:54:59,100 It's, like, six layers that all pull out and then separate, 1281 00:54:59,100 --> 00:55:01,500 and it's designed to be deployed in zero G, 1282 00:55:01,500 --> 00:55:03,066 so it's very thin Mylar 1283 00:55:03,066 --> 00:55:04,666 that's designed to be deployed in zero G. 1284 00:55:04,666 --> 00:55:08,966 It's very hard to test on Earth, and I remember being in meetings 1285 00:55:08,966 --> 00:55:12,266 where they were trying to test it in Long Beach, California, 1286 00:55:12,266 --> 00:55:14,300 where the telescope was assembled, 1287 00:55:14,300 --> 00:55:16,133 and they'd say, "Oh, yeah, they tried another test, 1288 00:55:16,133 --> 00:55:17,566 "and just all the cables, like, 1289 00:55:17,566 --> 00:55:18,933 "jumped out of their cables trays, 1290 00:55:18,933 --> 00:55:21,066 and it stopped, like, halfway through," 1291 00:55:21,066 --> 00:55:23,266 and you could just see people around the table be like, 1292 00:55:23,266 --> 00:55:24,633 "What are we doing," right? 1293 00:55:24,633 --> 00:55:27,333 And the woman in charge of NIRCam, when I worked for her, 1294 00:55:27,333 --> 00:55:28,666 I still remember her saying-- 1295 00:55:28,666 --> 00:55:30,366 She saw this, right, and was like, "Look. 1296 00:55:30,366 --> 00:55:32,933 "Nothing that any of us do right here 1297 00:55:32,933 --> 00:55:35,366 "is gonna affect what happens with the sun shield, right? 1298 00:55:35,366 --> 00:55:36,766 "There's a lot of very smart people 1299 00:55:36,766 --> 00:55:38,533 "who know exactly how important this is, 1300 00:55:38,533 --> 00:55:40,733 "who are working very hard to make sure it works right 1301 00:55:40,733 --> 00:55:43,266 "the first time because we only get one shot at it, 1302 00:55:43,266 --> 00:55:45,366 "and it's not worth worrying about. 1303 00:55:45,366 --> 00:55:48,733 None of your worrying is gonna affect what they do," right? 1304 00:55:48,733 --> 00:55:51,533 And one of the nice things about Webb was, 1305 00:55:51,533 --> 00:55:53,000 over time, it was pretty delayed, 1306 00:55:53,000 --> 00:55:54,666 but one of the nice things was that 1307 00:55:54,666 --> 00:55:56,466 one of the reasons it was delayed is 'cause 1308 00:55:56,466 --> 00:55:58,766 everybody wanted to make sure it worked the first time, 1309 00:55:58,766 --> 00:56:00,433 and it did. 1310 00:56:00,433 --> 00:56:01,800 It was pretty amazing. 1311 00:56:01,800 --> 00:56:04,400 There was pretty much no problems during commissioning. 1312 00:56:04,400 --> 00:56:06,900 Sun shield deployed the first time, no problem. 1313 00:56:06,900 --> 00:56:09,933 It still sort of amazes me that we didn't actually hit 1314 00:56:09,933 --> 00:56:12,000 some sort of major problem during that whole process, 1315 00:56:12,000 --> 00:56:14,766 but it all worked the first time just like it should've. 1316 00:56:19,433 --> 00:56:20,600 All right, well, thanks, guys. 1317 00:56:20,600 --> 00:56:21,766 This was fun. 1318 00:56:21,766 --> 00:56:24,166 [audience applauding]