1 00:00:08,600 --> 00:00:10,719 Speaker 1: Hey, or hey, did you follow the launch of the 2 00:00:10,840 --> 00:00:13,720 Speaker 1: James Webb telescope. Yeah, I thought, I want to be honest, 3 00:00:13,800 --> 00:00:16,480 Speaker 1: I was in Hawaii, so I wasn't plugged into the news, 4 00:00:16,520 --> 00:00:18,079 Speaker 1: but I saw that it was all over the place 5 00:00:18,160 --> 00:00:20,880 Speaker 1: and people were very excited and where you like terrifying 6 00:00:20,960 --> 00:00:23,080 Speaker 1: in the edge of your seat that it wasn't gonna work. Well, 7 00:00:23,079 --> 00:00:25,320 Speaker 1: I'm just glad it didn't explode on launch. I guess 8 00:00:25,320 --> 00:00:26,880 Speaker 1: that's always a good thing. So would you say that 9 00:00:26,920 --> 00:00:29,200 Speaker 1: the NASA team did like a good job of getting 10 00:00:29,200 --> 00:00:32,680 Speaker 1: everybody emotionally invested in this ten billion dollar project. It 11 00:00:32,720 --> 00:00:34,840 Speaker 1: was pretty dramatic, you know, and whenever you have a launch, 12 00:00:34,880 --> 00:00:36,639 Speaker 1: you know, anything can happen. And I know they had 13 00:00:36,640 --> 00:00:40,000 Speaker 1: some blaize and in some you know, expectations and people 14 00:00:40,040 --> 00:00:42,479 Speaker 1: were hanging by the seat of their pants right to 15 00:00:42,560 --> 00:00:44,720 Speaker 1: see the telescope opened up. But you know, it worked 16 00:00:44,720 --> 00:00:47,360 Speaker 1: so well and unfolded so smoothly. I was wondering if 17 00:00:47,400 --> 00:00:49,800 Speaker 1: it might have made like a better story if it 18 00:00:49,880 --> 00:00:51,960 Speaker 1: hadn't gone so well, if there's been some like ups 19 00:00:51,960 --> 00:00:56,040 Speaker 1: and downs. Were you hoping something would go wrong? Daniel, Yeah, 20 00:00:56,080 --> 00:00:57,600 Speaker 1: you know, you need a little bit of a dip 21 00:00:57,640 --> 00:00:59,760 Speaker 1: at the end so that our heroes can like triumph 22 00:00:59,800 --> 00:01:03,120 Speaker 1: and last moment I see, so the engineers can swoop 23 00:01:03,160 --> 00:01:05,160 Speaker 1: in and fix all the mistakes that the physicist me 24 00:01:05,800 --> 00:01:08,520 Speaker 1: exactly in the end, the engineers are always the heroes. 25 00:01:08,640 --> 00:01:26,200 Speaker 1: I'll watch that movie. I am Jorhan, made cartoonists and 26 00:01:26,200 --> 00:01:29,040 Speaker 1: the creator of PhD comics. Hi. I'm Daniel. I'm a 27 00:01:29,080 --> 00:01:31,920 Speaker 1: particle physicist and a professor at U SEE Irvine, and 28 00:01:31,959 --> 00:01:35,040 Speaker 1: I'm definitely buying a ticket for the movie called Engineers 29 00:01:35,160 --> 00:01:37,600 Speaker 1: Save the Day. But they do it every day, Daniel, 30 00:01:37,600 --> 00:01:40,000 Speaker 1: you don't need to buy a movie ticket. It's happening 31 00:01:40,000 --> 00:01:42,319 Speaker 1: around you all the time. But we need Hollywood to 32 00:01:42,400 --> 00:01:45,680 Speaker 1: like dramatize it, to you know, glorify these people. I see, 33 00:01:45,720 --> 00:01:47,680 Speaker 1: I see. Yeah, we need a big name movie star 34 00:01:47,960 --> 00:01:50,640 Speaker 1: or maybe cartoonists to play these characters on film. So 35 00:01:50,680 --> 00:01:53,000 Speaker 1: who's going to play you in the Hollywood version of 36 00:01:53,000 --> 00:01:57,600 Speaker 1: your life? I have thought about that question, Daniel. It's 37 00:01:57,600 --> 00:02:01,600 Speaker 1: gonna be Harry Chump. But welcome to our podcast. Daniel 38 00:02:01,600 --> 00:02:04,240 Speaker 1: and Jorge explain the Universe, a production of My Heart 39 00:02:04,320 --> 00:02:07,320 Speaker 1: Radio in which the scientists and the engineers really do 40 00:02:07,480 --> 00:02:10,800 Speaker 1: save the day by helping you crack the mysteries of 41 00:02:10,840 --> 00:02:13,800 Speaker 1: the universe. On this podcast, we think that the entire 42 00:02:13,880 --> 00:02:16,480 Speaker 1: mystery is like a fantastic puzzle. It's like a Christmas 43 00:02:16,480 --> 00:02:19,680 Speaker 1: present waiting to be unwrapped, and we cannot wait to 44 00:02:19,760 --> 00:02:22,880 Speaker 1: discover what the universe has to tell us. So we 45 00:02:23,040 --> 00:02:25,160 Speaker 1: love to talk about everything that's out there in the universe, 46 00:02:25,160 --> 00:02:27,880 Speaker 1: everything that's close by, everything that's far away, and explain 47 00:02:27,960 --> 00:02:30,040 Speaker 1: all of it to you. That's right, because scientists not 48 00:02:30,120 --> 00:02:32,840 Speaker 1: just save the day, but they also help us understand 49 00:02:32,880 --> 00:02:35,280 Speaker 1: the day, What makes the day? How how can we 50 00:02:35,320 --> 00:02:37,320 Speaker 1: have days and nights? Those were big questions in the 51 00:02:37,360 --> 00:02:40,440 Speaker 1: history of human civilization, and we figured it out. We 52 00:02:40,520 --> 00:02:43,000 Speaker 1: figured out that we are sitting on a big round 53 00:02:43,080 --> 00:02:46,760 Speaker 1: rock going around a big bright orbit that's a continual 54 00:02:46,919 --> 00:02:50,000 Speaker 1: explosion of fusion energy. And we didn't know that before, 55 00:02:50,040 --> 00:02:52,040 Speaker 1: but now we do. And probably there are lots of 56 00:02:52,200 --> 00:02:55,160 Speaker 1: unsung heroes in the history of those discoveries. Like we 57 00:02:55,240 --> 00:02:58,119 Speaker 1: talked about Galileo who looked through the telescope, but who 58 00:02:58,120 --> 00:03:01,000 Speaker 1: built that telescope, who really polished those lenses and make 59 00:03:01,040 --> 00:03:03,679 Speaker 1: sure the thing actually worked. Yeah, a lot of amazing 60 00:03:03,800 --> 00:03:07,399 Speaker 1: technicians who are behind the tools that scientists make. They 61 00:03:07,800 --> 00:03:09,560 Speaker 1: rarely get credit, right. I mean, they do get their 62 00:03:09,639 --> 00:03:13,280 Speaker 1: name in the three thousand author papers, right, or they don't. 63 00:03:13,440 --> 00:03:15,640 Speaker 1: Sometimes they don't. They just end up in the acknowledgements. 64 00:03:15,880 --> 00:03:18,280 Speaker 1: At least they got paid, right. You do pay the engineers, right. 65 00:03:19,480 --> 00:03:24,240 Speaker 1: I pay my engineers absolutely. But we have learned incredible 66 00:03:24,280 --> 00:03:26,360 Speaker 1: things about the nature of the universe. And every time 67 00:03:26,400 --> 00:03:29,400 Speaker 1: we open up new eyeballs, we illuminate new parts of 68 00:03:29,400 --> 00:03:31,919 Speaker 1: the universe, and it always comes with surprises. It always 69 00:03:31,919 --> 00:03:35,200 Speaker 1: tells us that the universe isn't quite as we expected. 70 00:03:35,360 --> 00:03:37,160 Speaker 1: And while we've been looking at the night sky for 71 00:03:37,280 --> 00:03:40,200 Speaker 1: thousands of years, it's only been the last few hundred 72 00:03:40,280 --> 00:03:43,520 Speaker 1: years that we've understood that there might be planets around 73 00:03:43,600 --> 00:03:46,600 Speaker 1: other stars, and only the last few decades that we've 74 00:03:46,600 --> 00:03:49,600 Speaker 1: been able to actually see some of those planets. Yeah, 75 00:03:49,600 --> 00:03:51,680 Speaker 1: it's pretty mind modeling. I get to think about the 76 00:03:51,800 --> 00:03:54,440 Speaker 1: arc of human history, right, and human knowledge, Like we 77 00:03:54,480 --> 00:03:57,600 Speaker 1: started out in caves or in Savannah's just you know, 78 00:03:57,680 --> 00:04:00,000 Speaker 1: trying to stay alive, thinking that what we can see 79 00:04:00,200 --> 00:04:02,440 Speaker 1: with our eyes is everything that there is about the world. 80 00:04:02,480 --> 00:04:05,040 Speaker 1: But then that's sort of expanded to the whole planet 81 00:04:05,200 --> 00:04:07,040 Speaker 1: and to the whole Solar System, and to the whole 82 00:04:07,080 --> 00:04:10,640 Speaker 1: galaxy and the whole multiple galaxies and galaxy clusters, and 83 00:04:10,680 --> 00:04:13,720 Speaker 1: maybe even other universes. That's why I'm always telling people 84 00:04:13,760 --> 00:04:17,200 Speaker 1: that physics matters, because it changes the whole context of 85 00:04:17,240 --> 00:04:19,559 Speaker 1: what it means to be alive, you know, the whole 86 00:04:19,560 --> 00:04:22,479 Speaker 1: scope of the universe. The stage on which your entire 87 00:04:22,600 --> 00:04:26,000 Speaker 1: life takes place on is determined by what we know 88 00:04:26,200 --> 00:04:29,400 Speaker 1: about the universe. And what's incredible is how much more 89 00:04:29,440 --> 00:04:31,800 Speaker 1: we know than people knew a thousand years ago, and 90 00:04:31,839 --> 00:04:34,800 Speaker 1: even a hundred years ago, and even twenty or thirty 91 00:04:34,880 --> 00:04:37,600 Speaker 1: years ago. There are things that are now routinely known 92 00:04:37,640 --> 00:04:39,840 Speaker 1: by just random people walking around on the street that 93 00:04:39,920 --> 00:04:44,599 Speaker 1: professional astronomers were dying to know just years ago. Yeah, 94 00:04:44,680 --> 00:04:48,279 Speaker 1: physics matters, and it also antimatters technically, right, there's a 95 00:04:48,279 --> 00:04:52,000 Speaker 1: certain symmetry about your role in human society. Fortunately, we 96 00:04:52,040 --> 00:04:55,240 Speaker 1: matter more than we antimatter, so there's a matter antimatter 97 00:04:55,320 --> 00:04:58,240 Speaker 1: asymmetry to physics. You have more matter than antimatter, or 98 00:04:58,279 --> 00:05:00,560 Speaker 1: more matter in general. I have noticed I've seen how 99 00:05:00,640 --> 00:05:02,880 Speaker 1: much coffee and cookies you guys consume in your seminars, 100 00:05:03,000 --> 00:05:05,280 Speaker 1: and donuts it's really more about the donuts. But yeah, 101 00:05:05,279 --> 00:05:07,760 Speaker 1: in the last few years, we've realized we've learned a 102 00:05:07,760 --> 00:05:11,159 Speaker 1: lot about our contacts are sort of place in the galaxy, 103 00:05:11,200 --> 00:05:13,800 Speaker 1: in the universe, and even in the last few decades 104 00:05:13,880 --> 00:05:16,479 Speaker 1: are sort of consciousness about where we are in the 105 00:05:16,520 --> 00:05:18,680 Speaker 1: universe and how rare we are has really sort of 106 00:05:18,800 --> 00:05:21,640 Speaker 1: almost exploded in a way. Absolutely, And as we learn 107 00:05:21,680 --> 00:05:23,839 Speaker 1: more about the universe, we get more answers, and those 108 00:05:23,880 --> 00:05:27,359 Speaker 1: answers just inspire more questions. Are the things that we 109 00:05:27,440 --> 00:05:31,040 Speaker 1: are seeing typical or are they weird and unusual? Are 110 00:05:31,080 --> 00:05:33,520 Speaker 1: there things out there still waiting to be discovered, what 111 00:05:33,640 --> 00:05:37,080 Speaker 1: surprises we just beyond our ability to see out into 112 00:05:37,080 --> 00:05:39,120 Speaker 1: the universe? And so to be On the podcast, we'll 113 00:05:39,160 --> 00:05:47,080 Speaker 1: be asking the question what is the future of exo 114 00:05:47,160 --> 00:05:50,320 Speaker 1: planet research? Exo planets? That's always a cool word. It 115 00:05:50,400 --> 00:05:52,440 Speaker 1: is a really cool word. I love putting exo in 116 00:05:52,480 --> 00:05:55,560 Speaker 1: front of everything. We have exo planets, we have exo moons. 117 00:05:55,920 --> 00:05:58,200 Speaker 1: One day will drink exo coffee. Well, I can't wait 118 00:05:58,200 --> 00:06:00,720 Speaker 1: for the exo physicists, you know, get them out of here. 119 00:06:02,120 --> 00:06:05,080 Speaker 1: I hope one day we have exo podcast listeners meeting 120 00:06:05,400 --> 00:06:09,000 Speaker 1: people in other Solar system subscribing to the podcast. Well, 121 00:06:09,040 --> 00:06:12,200 Speaker 1: technically every listener is an extra podcast listener because they're 122 00:06:12,240 --> 00:06:15,400 Speaker 1: not in the podcast, right, Extra means like outside of Yeah, 123 00:06:15,480 --> 00:06:18,080 Speaker 1: that's true. Yeah, they're in orbit around the podcast. Yeah. So, 124 00:06:18,080 --> 00:06:20,400 Speaker 1: in the last few decades, there's been sort of an 125 00:06:20,440 --> 00:06:23,840 Speaker 1: explosion in our knowledge about planets and other solar systems, 126 00:06:23,839 --> 00:06:26,200 Speaker 1: that is, planets that are not in our Solar system, 127 00:06:26,240 --> 00:06:28,400 Speaker 1: that are not you know, going around our Sun. It 128 00:06:28,480 --> 00:06:30,479 Speaker 1: really is incredible how much we have learned just in 129 00:06:30,520 --> 00:06:33,040 Speaker 1: the last few decades. In the nineties, we had never 130 00:06:33,200 --> 00:06:36,800 Speaker 1: seen another planet around another star. For all we knew, 131 00:06:36,839 --> 00:06:38,920 Speaker 1: this was the only star in the universe that had 132 00:06:39,000 --> 00:06:41,000 Speaker 1: planets around it, in the same way that we still 133 00:06:41,040 --> 00:06:43,520 Speaker 1: don't know if there is life around any other star. 134 00:06:43,640 --> 00:06:46,159 Speaker 1: We didn't even know if there were planets around any 135 00:06:46,200 --> 00:06:49,840 Speaker 1: other star until the ninety nineties, and slowly we saw 136 00:06:49,880 --> 00:06:51,720 Speaker 1: one and then two, and now, as you say, there's 137 00:06:51,720 --> 00:06:55,160 Speaker 1: been a veritable explosion of these discoveries. Right well before 138 00:06:55,200 --> 00:06:57,880 Speaker 1: the nineties, I guess we imagined it or we assumed it, 139 00:06:58,000 --> 00:06:59,839 Speaker 1: right like we saw these stars out there and the 140 00:07:00,080 --> 00:07:01,960 Speaker 1: verse in the galaxy, and we imagine, like, you know, 141 00:07:02,040 --> 00:07:04,240 Speaker 1: we can't be the only star with the planet, so 142 00:07:04,279 --> 00:07:06,960 Speaker 1: there must be planets around other stars. We just didn't 143 00:07:07,000 --> 00:07:09,160 Speaker 1: have like direct evidence or proof of it. That's right, 144 00:07:09,200 --> 00:07:10,800 Speaker 1: we didn't have direct evidence. But you know, if you 145 00:07:10,840 --> 00:07:13,280 Speaker 1: read back into the history, it's sort of surprising how 146 00:07:13,320 --> 00:07:15,679 Speaker 1: long it took people to put those two things together 147 00:07:15,800 --> 00:07:18,040 Speaker 1: to realize, Hold, on a second, there are planets around 148 00:07:18,040 --> 00:07:21,720 Speaker 1: our star. There might be planets around other stars. That 149 00:07:21,840 --> 00:07:24,200 Speaker 1: seems sort of obvious, but it wasn't until a few 150 00:07:24,280 --> 00:07:26,800 Speaker 1: hundred years ago that people put those two ideas together 151 00:07:26,840 --> 00:07:29,640 Speaker 1: and wondered how many planets might be out there in 152 00:07:29,760 --> 00:07:31,800 Speaker 1: other solar systems. And these days it's sort of a 153 00:07:31,840 --> 00:07:35,840 Speaker 1: bonanza of exoplanet discoveries, and that make even more explosive 154 00:07:35,880 --> 00:07:38,680 Speaker 1: as we get the new James Webb Space Telescope up 155 00:07:38,680 --> 00:07:41,680 Speaker 1: and running, which just launched recently in December, right, that's right, 156 00:07:41,880 --> 00:07:45,000 Speaker 1: very exciting moment for the entire astronomy community. Everybody on 157 00:07:45,120 --> 00:07:48,840 Speaker 1: pins and needles as their ten billion dollar toy launched 158 00:07:48,880 --> 00:07:52,200 Speaker 1: and then unfolded in space without a hitch. And it's 159 00:07:52,200 --> 00:07:54,840 Speaker 1: always very exciting in these moments when you open up 160 00:07:54,840 --> 00:07:57,480 Speaker 1: a new eyeball onto the universe, because it shows you 161 00:07:57,760 --> 00:08:00,840 Speaker 1: things that nobody has ever seen. No human has ever 162 00:08:00,960 --> 00:08:03,680 Speaker 1: known these facts, and we will soon get data from it, 163 00:08:03,720 --> 00:08:05,680 Speaker 1: and he will tell us things about the universe that 164 00:08:05,760 --> 00:08:08,240 Speaker 1: no human has ever known before. So to give us 165 00:08:08,280 --> 00:08:11,440 Speaker 1: some contexts in sort of the current status of exoplanet 166 00:08:11,560 --> 00:08:15,240 Speaker 1: research or search for other planets outside of our solarcism, 167 00:08:15,280 --> 00:08:17,480 Speaker 1: we thought we'd bring in a guest, a very special 168 00:08:17,760 --> 00:08:21,520 Speaker 1: scientist who specializes in sort of tewing up all of 169 00:08:21,520 --> 00:08:24,160 Speaker 1: these exo planets. All right, so it's my pleasure to 170 00:08:24,320 --> 00:08:28,720 Speaker 1: introduce our guest on today's podcast, Dr Jesse Christensen. She's 171 00:08:28,720 --> 00:08:32,320 Speaker 1: a Project scientist of the NASA Exo Planet Archive and 172 00:08:32,400 --> 00:08:36,200 Speaker 1: also a research scientist at the NASA Exo Planet Science 173 00:08:36,280 --> 00:08:39,000 Speaker 1: Institute at cal Tech. She has a pH d in 174 00:08:39,120 --> 00:08:41,880 Speaker 1: two thousand seven from the University of New South Wales 175 00:08:42,080 --> 00:08:44,960 Speaker 1: in Australia. She's won a bunch of awards, including in 176 00:08:45,040 --> 00:08:49,200 Speaker 1: two thousand eighteen the NASA Exceptional Engineering Achievement METAL and 177 00:08:49,280 --> 00:08:53,120 Speaker 1: also the University of Southern Queensland Research Giant. I was 178 00:08:53,120 --> 00:08:55,360 Speaker 1: wondering if that was actually a typo on your CV. 179 00:08:55,640 --> 00:09:01,320 Speaker 1: Is that giant or grant? It is actually giant? So 180 00:09:01,360 --> 00:09:04,200 Speaker 1: you are a giant of research in someone's eyes, I 181 00:09:04,240 --> 00:09:06,920 Speaker 1: am a giant research? Was it a giant grant as well? 182 00:09:07,000 --> 00:09:09,320 Speaker 1: I wish it had come with like a giant novelty thing. 183 00:09:09,760 --> 00:09:11,880 Speaker 1: It didn't. I've got a little framed thing though. It's nice. 184 00:09:11,960 --> 00:09:15,680 Speaker 1: She's also very active on Twitter as Aussie astronomer, where 185 00:09:15,679 --> 00:09:19,600 Speaker 1: she recently coined a new phrase in astronomy, which is 186 00:09:19,640 --> 00:09:22,440 Speaker 1: the name of people who live in the milky Way. 187 00:09:22,679 --> 00:09:26,040 Speaker 1: You called us the milky Wegians. I did, I did, 188 00:09:26,160 --> 00:09:30,280 Speaker 1: after some thought, after some consideration, that's what I landed on. Wait, 189 00:09:30,320 --> 00:09:33,560 Speaker 1: what's the term milky Wigian milky region? I was looking 190 00:09:33,640 --> 00:09:36,400 Speaker 1: for other places that ended in way, and I landed 191 00:09:36,400 --> 00:09:39,720 Speaker 1: on Goalway, and people from Goalway are called goal Regions. 192 00:09:40,160 --> 00:09:42,320 Speaker 1: And I was like, there, it is so milky regions. 193 00:09:42,600 --> 00:09:45,559 Speaker 1: It sounds sort of like witchcrafty maybe, like or am 194 00:09:45,559 --> 00:09:49,199 Speaker 1: I thinking wicked Wickan? Oh yes, so so not milky Wickens. 195 00:09:49,320 --> 00:09:52,680 Speaker 1: That would be something different. That's the other planet exactly. 196 00:09:52,720 --> 00:09:55,400 Speaker 1: That's right. That's what happens when which is spilled their 197 00:09:55,400 --> 00:09:59,320 Speaker 1: breakfast cereal all over themselves. They're milky Wickens. Anyway, we 198 00:09:59,360 --> 00:10:01,520 Speaker 1: are a milky regions, all of us, and we are 199 00:10:01,600 --> 00:10:04,920 Speaker 1: curious about the nature of the galaxy and the planets 200 00:10:04,920 --> 00:10:07,360 Speaker 1: in it and all the planets that are around stars 201 00:10:07,600 --> 00:10:10,200 Speaker 1: other places in the galaxy, and so we've asked Jesse 202 00:10:10,320 --> 00:10:12,079 Speaker 1: to come on the podcast and answer all of our 203 00:10:12,160 --> 00:10:15,760 Speaker 1: questions about exo planets past and future. Thanks very much 204 00:10:15,760 --> 00:10:17,400 Speaker 1: for joining us today. Thank you for having me. I'm 205 00:10:17,400 --> 00:10:19,719 Speaker 1: excited to be here. Wonderful. So first I think we 206 00:10:19,760 --> 00:10:23,400 Speaker 1: should get started just with the basics of exo planets. 207 00:10:23,400 --> 00:10:26,640 Speaker 1: How is it that we can see exo planets planets 208 00:10:26,679 --> 00:10:29,160 Speaker 1: around other stars? From Earth? I mean, if I look 209 00:10:29,200 --> 00:10:31,240 Speaker 1: up in the night sky, we can just barely see 210 00:10:31,280 --> 00:10:34,160 Speaker 1: the stars. How is it possible to see planets going 211 00:10:34,200 --> 00:10:37,520 Speaker 1: around those stars? You've really hit on the verb there. 212 00:10:37,760 --> 00:10:41,440 Speaker 1: So see, we don't actually see almost any of the 213 00:10:41,440 --> 00:10:44,079 Speaker 1: planets that we find. What we do is we look 214 00:10:44,120 --> 00:10:47,440 Speaker 1: at the stars that they orbit and observe changes of 215 00:10:47,520 --> 00:10:50,200 Speaker 1: those stars that are induced by the presence of the planet. 216 00:10:50,720 --> 00:10:52,600 Speaker 1: And we can do this a few different ways. The 217 00:10:52,640 --> 00:10:56,160 Speaker 1: planets pull gravitationally on the stars, so the stars actually 218 00:10:56,200 --> 00:10:58,520 Speaker 1: wobble in the sky, and we can see that when 219 00:10:58,600 --> 00:11:01,360 Speaker 1: we measure their velocity, and we measured their precision very 220 00:11:01,360 --> 00:11:03,880 Speaker 1: precisely the stars are all kind of just wobbling around 221 00:11:03,880 --> 00:11:05,560 Speaker 1: in the sky a little bit. If they have planets. 222 00:11:06,160 --> 00:11:08,480 Speaker 1: Another way we see them is if the planet orbiting 223 00:11:08,520 --> 00:11:10,720 Speaker 1: the star blocks some of the light from the star. 224 00:11:10,880 --> 00:11:13,480 Speaker 1: If it's lined up just right and eclipses the start, 225 00:11:13,520 --> 00:11:15,440 Speaker 1: then we see that the brightness of the star changes. 226 00:11:15,640 --> 00:11:18,240 Speaker 1: So you're right, it's very difficult to see planets. So 227 00:11:18,280 --> 00:11:20,000 Speaker 1: what we really do is look at the stars and 228 00:11:20,040 --> 00:11:23,080 Speaker 1: see the changes induced by the planets. It's pretty wild 229 00:11:23,160 --> 00:11:25,360 Speaker 1: to think about that all the stars are out there, 230 00:11:25,400 --> 00:11:27,640 Speaker 1: at least the ones with planets are wiggling, you know, 231 00:11:27,720 --> 00:11:29,120 Speaker 1: like if you look at the night sky, that means 232 00:11:29,160 --> 00:11:32,720 Speaker 1: most of those stars are wiggling. Even our Sun is wiggling. Yeah, 233 00:11:32,840 --> 00:11:36,000 Speaker 1: so actually Jupiter, which has about one percent the mass 234 00:11:36,000 --> 00:11:39,280 Speaker 1: of our Solar system, is actually dragging our Sun around 235 00:11:39,360 --> 00:11:41,760 Speaker 1: the middle of our solar system. So if you were 236 00:11:41,760 --> 00:11:44,840 Speaker 1: an alien civilization looking at our Sun, you would basically 237 00:11:44,840 --> 00:11:48,359 Speaker 1: see that it's moving with this roughly twelve year periodicity 238 00:11:48,400 --> 00:11:50,360 Speaker 1: in the middle of our Solar system, and from that 239 00:11:50,400 --> 00:11:52,600 Speaker 1: you could infer that there was a giant planet on 240 00:11:52,640 --> 00:11:54,760 Speaker 1: a twelve year orbit pulling it around, and then you 241 00:11:54,760 --> 00:11:57,160 Speaker 1: could guess that we had a Jupiter like planet, could 242 00:11:57,160 --> 00:11:59,959 Speaker 1: they guess that we're here? If they had really really 243 00:12:00,080 --> 00:12:03,599 Speaker 1: really really really precise instrumentation, more precise than the instrumentation 244 00:12:03,640 --> 00:12:06,200 Speaker 1: that we have been able to develop so far, they could, 245 00:12:06,240 --> 00:12:08,520 Speaker 1: in fact in further presence of Earth and in fact 246 00:12:08,559 --> 00:12:10,439 Speaker 1: the whole Solar system. But this is a leap in 247 00:12:10,480 --> 00:12:12,600 Speaker 1: technology that we have not made yet, and that makes 248 00:12:12,640 --> 00:12:16,000 Speaker 1: me wonder, like, what can they know about Jupiter? So 249 00:12:16,040 --> 00:12:18,040 Speaker 1: you say that they could see the jupiters here, what 250 00:12:18,120 --> 00:12:20,800 Speaker 1: exactly can they know because they can't see it directly, 251 00:12:20,880 --> 00:12:23,760 Speaker 1: So can they know things like it's orbital period, and 252 00:12:23,760 --> 00:12:26,520 Speaker 1: it's mass and its volume and what it's made out of? 253 00:12:26,520 --> 00:12:29,439 Speaker 1: What can we actually know about these planets? Right? So, 254 00:12:29,520 --> 00:12:31,920 Speaker 1: if they could only see the wobble of the star, 255 00:12:32,600 --> 00:12:34,880 Speaker 1: basically the only thing they'd be able to measure would 256 00:12:34,880 --> 00:12:36,839 Speaker 1: be its orbital period, so how long it takes to 257 00:12:36,880 --> 00:12:40,360 Speaker 1: ground the star and the component of its mass that's 258 00:12:40,400 --> 00:12:42,840 Speaker 1: along the line of sight between the star and them, 259 00:12:43,000 --> 00:12:45,559 Speaker 1: Which is to say that if Jupiter is lined up 260 00:12:45,800 --> 00:12:48,559 Speaker 1: just right so that it's orbiting between the star and 261 00:12:48,840 --> 00:12:51,560 Speaker 1: the observer, then that is the maximal pull that we 262 00:12:51,600 --> 00:12:54,319 Speaker 1: can see. That's the maximum wobble will be if it's 263 00:12:54,320 --> 00:12:56,320 Speaker 1: lined up just right. But most of the planets aren't 264 00:12:56,320 --> 00:12:58,600 Speaker 1: lined up just right. They're tilted a little bit compared 265 00:12:58,640 --> 00:13:00,719 Speaker 1: to that that plane, so some of the pull of 266 00:13:00,760 --> 00:13:02,920 Speaker 1: the star is in a direction we can't see. It's 267 00:13:02,920 --> 00:13:05,160 Speaker 1: in a direction, you know, orthogonal to our line of sight, 268 00:13:05,440 --> 00:13:07,040 Speaker 1: at right angles to our line of sight, so we 269 00:13:07,080 --> 00:13:09,520 Speaker 1: don't see that component. We only see the component of 270 00:13:09,600 --> 00:13:12,360 Speaker 1: the wobble that's in our direction. So we get a 271 00:13:12,400 --> 00:13:14,280 Speaker 1: minimum mass, we call it. So you get an orbital 272 00:13:14,320 --> 00:13:16,840 Speaker 1: period and a minimum mass. So if a Jupiter, for instance, 273 00:13:16,840 --> 00:13:18,920 Speaker 1: they'd get some minimum mass of one jupiter mass and 274 00:13:18,920 --> 00:13:21,480 Speaker 1: then be like, okay, it's a gas giant. And we know, 275 00:13:21,920 --> 00:13:24,319 Speaker 1: given the way things are constructed in the galaxy, if 276 00:13:24,320 --> 00:13:26,360 Speaker 1: you have something that weighs the jupidter mass, you know 277 00:13:26,440 --> 00:13:29,520 Speaker 1: that it's mostly hydrogen and helium. It's not mostly rock 278 00:13:29,640 --> 00:13:32,200 Speaker 1: or mostly ice. It's mostly hydrogen helium. So you could 279 00:13:32,200 --> 00:13:34,040 Speaker 1: infer that it was a gas giant. So you'd have 280 00:13:34,080 --> 00:13:36,800 Speaker 1: its period, you'd have its mass, a minimum mass, and 281 00:13:36,840 --> 00:13:39,880 Speaker 1: you'd have some guess at its bulk composition. The other 282 00:13:39,920 --> 00:13:41,680 Speaker 1: thing you could know if you know what kind of 283 00:13:41,679 --> 00:13:44,320 Speaker 1: star it's orbiting. Is it's temperature, because the orbit all 284 00:13:44,360 --> 00:13:46,960 Speaker 1: period tells you how far away from the star it is. 285 00:13:47,360 --> 00:13:49,720 Speaker 1: So Earth with our period of three hundred and sixty 286 00:13:49,720 --> 00:13:51,880 Speaker 1: five years, is just the right distance to get the 287 00:13:51,960 --> 00:13:54,280 Speaker 1: right amount of radiation from the Sun for water to 288 00:13:54,320 --> 00:13:56,280 Speaker 1: be liquid on the surface. And that's kind of the 289 00:13:56,280 --> 00:13:58,040 Speaker 1: holy grail of what we're doing right now, trying to 290 00:13:58,080 --> 00:14:00,400 Speaker 1: find planets that at this right temperature so be able 291 00:14:00,440 --> 00:14:03,360 Speaker 1: to guess it's temperature, it's it's rough equilibrium temperature, knowing 292 00:14:03,360 --> 00:14:05,000 Speaker 1: how far it was from the Sun. So you can 293 00:14:05,040 --> 00:14:07,680 Speaker 1: actually get a lot just from this wobble on the sky. 294 00:14:07,840 --> 00:14:09,760 Speaker 1: I think that's really fascinating you say that you can 295 00:14:09,880 --> 00:14:12,680 Speaker 1: guess what's in the planet just from knowing how big 296 00:14:12,720 --> 00:14:14,839 Speaker 1: it is. Is that just from knowing like how much 297 00:14:14,920 --> 00:14:18,120 Speaker 1: hydrogen and helium and lithium and uranium there is out 298 00:14:18,160 --> 00:14:20,600 Speaker 1: there in the universe that you're guessing how much of 299 00:14:20,640 --> 00:14:23,520 Speaker 1: a serving of each of those components a big planet 300 00:14:23,600 --> 00:14:26,240 Speaker 1: might get. Yeah, so we can start with what we 301 00:14:26,360 --> 00:14:29,640 Speaker 1: think a protoplanetary disk is made of. So when a 302 00:14:29,760 --> 00:14:32,480 Speaker 1: star is born, it's born from a cloud of dust 303 00:14:32,480 --> 00:14:35,120 Speaker 1: and gas, and the amount of dust in that cloud 304 00:14:35,240 --> 00:14:37,920 Speaker 1: dust is basically like the solid materials that aren't in 305 00:14:38,000 --> 00:14:40,160 Speaker 1: gash is formed. The amount of dust in that cloud 306 00:14:40,200 --> 00:14:43,400 Speaker 1: basically puts a limit on how many rocky planets or 307 00:14:43,480 --> 00:14:45,800 Speaker 1: rocky cores of bigger planets you can make out of 308 00:14:45,800 --> 00:14:48,200 Speaker 1: this protoplanetary disk. It's like making a cake. If you 309 00:14:48,280 --> 00:14:49,880 Speaker 1: only have two eggs, you're only going to be able 310 00:14:49,880 --> 00:14:52,000 Speaker 1: to make one cake. If you have six eggs, maybe 311 00:14:52,000 --> 00:14:54,440 Speaker 1: you can make three cakes or one three tier cake. 312 00:14:54,560 --> 00:14:57,720 Speaker 1: So you're really constrained by these ingredients in your initial 313 00:14:57,880 --> 00:15:00,360 Speaker 1: disk of material that's creating your planets. But that's sort 314 00:15:00,360 --> 00:15:03,000 Speaker 1: of statistical, right. It's like if somebody took everything in 315 00:15:03,000 --> 00:15:05,720 Speaker 1: the grocery store and then blended it up into a tornado. 316 00:15:05,880 --> 00:15:08,120 Speaker 1: You're talking about like how much flour and how many 317 00:15:08,160 --> 00:15:10,560 Speaker 1: eggs might fall into a planet. You don't actually know 318 00:15:10,720 --> 00:15:14,440 Speaker 1: for an individual planet whether it's like unusually large lump 319 00:15:14,440 --> 00:15:17,120 Speaker 1: of uranium and its core something. Is that right? Right? So, 320 00:15:17,240 --> 00:15:19,880 Speaker 1: for instance, if you were in an American supermarket and 321 00:15:19,920 --> 00:15:22,280 Speaker 1: you blended everything up, your planets would have a lot 322 00:15:22,280 --> 00:15:24,080 Speaker 1: of cereal in them. There'd be a lot of breakfast 323 00:15:24,120 --> 00:15:27,120 Speaker 1: cereal compared to other countries that I've lived in right, 324 00:15:27,160 --> 00:15:29,960 Speaker 1: there wouldn't be any veggie mate for example, exactly, you 325 00:15:29,960 --> 00:15:32,600 Speaker 1: wouldn't have your vegemite flavored planets. One thing we do 326 00:15:32,760 --> 00:15:35,520 Speaker 1: know is if you have something the size of Earth 327 00:15:36,160 --> 00:15:38,800 Speaker 1: that's not really big enough if it's just a hydrogen 328 00:15:38,800 --> 00:15:42,120 Speaker 1: and helium bowl to hold itself together compared to all 329 00:15:42,120 --> 00:15:44,320 Speaker 1: of the other forces that are going on in the 330 00:15:44,320 --> 00:15:46,720 Speaker 1: formation and evolution of a planetary system. So if you 331 00:15:46,760 --> 00:15:49,080 Speaker 1: have something that's the size of Earth, you're pretty sure 332 00:15:49,120 --> 00:15:52,480 Speaker 1: it's mostly rock, just given you know the amount of 333 00:15:52,520 --> 00:15:56,160 Speaker 1: gravitational pole you need to hold something together. So you 334 00:15:56,200 --> 00:15:58,560 Speaker 1: couldn't really have like a tiny gas dwarf because it 335 00:15:58,560 --> 00:16:01,240 Speaker 1: would just disperse. And that's the wabbling rate. But from 336 00:16:01,280 --> 00:16:03,400 Speaker 1: the eclipse, and I think we can can we tell 337 00:16:03,440 --> 00:16:05,920 Speaker 1: other things about the planets. If the planet's eclipsing, we 338 00:16:05,960 --> 00:16:09,200 Speaker 1: can get so much more information. Is really quite great, 339 00:16:09,240 --> 00:16:11,160 Speaker 1: and that's the method that I use. So now I'm 340 00:16:11,160 --> 00:16:14,520 Speaker 1: going to like percetialize about the transit method. So if 341 00:16:14,560 --> 00:16:17,000 Speaker 1: the planet goes in front of the star, and you 342 00:16:17,040 --> 00:16:19,200 Speaker 1: know how big the star is, and you can measure 343 00:16:19,400 --> 00:16:22,160 Speaker 1: how much dimmer the star gets, then you know how 344 00:16:22,240 --> 00:16:24,920 Speaker 1: big in size the planet must be to block that 345 00:16:25,040 --> 00:16:27,640 Speaker 1: much light. So, for instance, Jupiter in front of the 346 00:16:27,680 --> 00:16:30,200 Speaker 1: Sun blocks about one percent of the light. So if 347 00:16:30,200 --> 00:16:32,360 Speaker 1: you're looking at a sun like star and you see 348 00:16:32,360 --> 00:16:34,360 Speaker 1: that something's blocking one percent of the light, you know 349 00:16:34,360 --> 00:16:37,920 Speaker 1: it's a Jupiter sized planet. Once you have size and mass, 350 00:16:37,960 --> 00:16:40,160 Speaker 1: now you can really start to say things about the 351 00:16:40,200 --> 00:16:42,080 Speaker 1: density of the planet and what it might be made 352 00:16:42,080 --> 00:16:44,480 Speaker 1: of and really start to constrain, oh, it must be 353 00:16:45,680 --> 00:16:49,320 Speaker 1: rock and a gaseous atmosphere. The other cool thing about 354 00:16:49,360 --> 00:16:51,440 Speaker 1: planets that go in front of stars is that their 355 00:16:51,480 --> 00:16:54,120 Speaker 1: atmospheres go in front of the stars as well. Now 356 00:16:54,360 --> 00:16:57,000 Speaker 1: picture the Earth to the Earth is a rock and 357 00:16:57,040 --> 00:17:00,520 Speaker 1: it has this thin gaseous atmosphere around it. Now you're again, 358 00:17:00,600 --> 00:17:03,000 Speaker 1: let's be this alien civilization looking at the Sun. If 359 00:17:03,080 --> 00:17:05,280 Speaker 1: you were lined up just right so that the Earth 360 00:17:05,440 --> 00:17:07,600 Speaker 1: passed in front of the Sun and block some of 361 00:17:07,640 --> 00:17:11,200 Speaker 1: the light, then the sunlight would go through the Earth's atmosphere, 362 00:17:11,359 --> 00:17:13,240 Speaker 1: but just the pain a little bit through the thin 363 00:17:13,320 --> 00:17:16,119 Speaker 1: layer of atmosphere. Yes, it would be a tiny amount 364 00:17:16,119 --> 00:17:19,000 Speaker 1: of the atmosphere, but the molecules in that atmosphere, so 365 00:17:19,080 --> 00:17:22,480 Speaker 1: our atmosphere has got oxygen, it's got nitrogen, it's got water. 366 00:17:23,040 --> 00:17:27,359 Speaker 1: The molecules in the atmosphere block some certain wavelengths of light. So, 367 00:17:27,400 --> 00:17:30,040 Speaker 1: for instance, if you look at the Earth's atmosphere at 368 00:17:30,080 --> 00:17:33,720 Speaker 1: one point four micron wavelength light, which is where water absorbs, 369 00:17:34,000 --> 00:17:37,520 Speaker 1: the Earth actually looks bigger because the atmosphere is opaque 370 00:17:37,600 --> 00:17:40,280 Speaker 1: at one point four microns because of the water. So 371 00:17:40,280 --> 00:17:42,320 Speaker 1: this is what we do for planets around other stars. 372 00:17:42,560 --> 00:17:45,119 Speaker 1: We look at their size as a function of wavelength 373 00:17:45,160 --> 00:17:47,920 Speaker 1: to work out when is their atmosphere opaque and when 374 00:17:48,000 --> 00:17:51,080 Speaker 1: is it transparent, And that tells us what molecules must 375 00:17:51,119 --> 00:17:53,920 Speaker 1: be in that atmosphere, blocking light at certain wavelengths and 376 00:17:54,000 --> 00:17:56,199 Speaker 1: letting it through another wavelengths. So we have this like 377 00:17:56,280 --> 00:17:59,960 Speaker 1: spectral fingerprint of the atmosphere of the planet on the 378 00:18:00,040 --> 00:18:02,840 Speaker 1: really just the brightness of the star changing at different wavelengths. 379 00:18:02,920 --> 00:18:04,879 Speaker 1: And then you start to be able to say, okay, cool, 380 00:18:05,000 --> 00:18:08,240 Speaker 1: this planet's got me sane, it's got carbon dioxide, it's 381 00:18:08,240 --> 00:18:11,200 Speaker 1: got iron rain coming down out of the atmosphere. You 382 00:18:11,200 --> 00:18:13,360 Speaker 1: can tell so much cool stuff. If you can see 383 00:18:13,400 --> 00:18:16,359 Speaker 1: into the atmosphere. It's like watching the star rise over 384 00:18:16,400 --> 00:18:20,280 Speaker 1: the planet, right, It's like sunrise and sunset. It's incredible exactly, 385 00:18:20,320 --> 00:18:22,760 Speaker 1: and our atmosphere, you know, it does interesting things to 386 00:18:22,800 --> 00:18:24,679 Speaker 1: the Sun as sunrise and sunset, And it's the same 387 00:18:24,760 --> 00:18:27,320 Speaker 1: kind of thing. The more atmosphere the light is going through, 388 00:18:27,680 --> 00:18:30,760 Speaker 1: the more imprint of the planet's atmosphere, it goes on 389 00:18:30,800 --> 00:18:32,639 Speaker 1: the sunlight. And you said a couple of times, like 390 00:18:32,760 --> 00:18:35,239 Speaker 1: if things are lined up just right, you know, if 391 00:18:35,320 --> 00:18:39,240 Speaker 1: Jupiter passes across the line of the Sun between you know, 392 00:18:39,280 --> 00:18:42,760 Speaker 1: the Sun and these observing aliens, then these methods can work. 393 00:18:42,880 --> 00:18:45,080 Speaker 1: It seems like things have to be lined up kind 394 00:18:45,080 --> 00:18:47,280 Speaker 1: of in a lucky way. Doesn't that really limit our 395 00:18:47,320 --> 00:18:50,960 Speaker 1: ability to discover exoplanets? Yeah, so using the transit method, 396 00:18:51,000 --> 00:18:54,560 Speaker 1: it really does limit us. So an earthlike planet around 397 00:18:54,560 --> 00:18:56,280 Speaker 1: a star like the Sun has about a one in 398 00:18:56,440 --> 00:18:59,280 Speaker 1: two hundred chance of transitting from our point of view 399 00:18:59,400 --> 00:19:01,159 Speaker 1: as we look at all the stars around us. What 400 00:19:01,240 --> 00:19:02,720 Speaker 1: that means is that you really have to look at 401 00:19:02,760 --> 00:19:05,120 Speaker 1: a lot of stars in order to catch the ones 402 00:19:05,160 --> 00:19:07,679 Speaker 1: that are lined up just right. So the NASA Kepler 403 00:19:07,680 --> 00:19:10,320 Speaker 1: mission that I worked on for ten years looked at 404 00:19:10,320 --> 00:19:13,720 Speaker 1: two hundred thousand stars to try and find the systems 405 00:19:13,720 --> 00:19:15,600 Speaker 1: that were lined up just right. So that's with the 406 00:19:15,600 --> 00:19:17,960 Speaker 1: transit method. There are other methods like the wobble method. 407 00:19:18,040 --> 00:19:19,800 Speaker 1: You don't need to be lined up just right. There 408 00:19:19,880 --> 00:19:22,560 Speaker 1: is also, going back to your very very original question, 409 00:19:22,680 --> 00:19:25,119 Speaker 1: there's a method called the direct imaging method, which is 410 00:19:25,160 --> 00:19:28,480 Speaker 1: basically exactly what it sounds. If the star is close 411 00:19:28,600 --> 00:19:31,159 Speaker 1: enough to us that the separation between the star and 412 00:19:31,200 --> 00:19:33,760 Speaker 1: the planet on the sky is big enough we have 413 00:19:33,920 --> 00:19:36,639 Speaker 1: we actually have like pretty exquisite instrumentation that you can 414 00:19:36,800 --> 00:19:40,320 Speaker 1: use to block out the starlight very carefully and look 415 00:19:40,359 --> 00:19:43,199 Speaker 1: around the star to find any little glowing points of 416 00:19:43,280 --> 00:19:46,200 Speaker 1: light which could be planets. So we do have a handful, 417 00:19:46,600 --> 00:19:49,520 Speaker 1: maybe a few dozen now directly image planets. Now, this 418 00:19:49,640 --> 00:19:52,480 Speaker 1: mostly only works for very big planets, like even bigger 419 00:19:52,480 --> 00:19:55,359 Speaker 1: than Jupiter, that are quite young, because as planets are 420 00:19:55,359 --> 00:19:57,600 Speaker 1: forming and the and the balls of gas and contracting, 421 00:19:57,600 --> 00:20:00,640 Speaker 1: they're radiating out this heat which makes them bright at 422 00:20:00,640 --> 00:20:04,159 Speaker 1: certain wavelengths. So we can directly image some kinds of 423 00:20:04,280 --> 00:20:06,960 Speaker 1: young giant planets and then it doesn't matter how they're 424 00:20:07,000 --> 00:20:08,479 Speaker 1: lined up, But we do have to be looking at 425 00:20:08,480 --> 00:20:10,520 Speaker 1: the system at the right time to kind of maximize 426 00:20:10,560 --> 00:20:12,600 Speaker 1: that separation between the star and planet. So there's still 427 00:20:12,640 --> 00:20:14,719 Speaker 1: a timing issue. It's sort of like you're trying to 428 00:20:15,000 --> 00:20:17,200 Speaker 1: measure the number of cats in your neighborhood, but you 429 00:20:17,280 --> 00:20:18,919 Speaker 1: know you're not very good at spotting them, and so 430 00:20:19,119 --> 00:20:21,040 Speaker 1: like every time you see a cat, you imagine, well, 431 00:20:21,359 --> 00:20:23,440 Speaker 1: I saw this one cat. That must be actually two 432 00:20:23,520 --> 00:20:26,080 Speaker 1: hundred cats out there that I'm not seeing. You have 433 00:20:26,119 --> 00:20:29,160 Speaker 1: to have this like estimate of your inability to see 434 00:20:29,200 --> 00:20:31,439 Speaker 1: planets so you can like extrapolate from what you do 435 00:20:31,560 --> 00:20:34,960 Speaker 1: see to what's actually out there, right, And that's actually 436 00:20:35,119 --> 00:20:37,959 Speaker 1: exactly what I did on the Massa Caple mission. I 437 00:20:38,040 --> 00:20:41,440 Speaker 1: injected fake planets into the data to see how good 438 00:20:41,480 --> 00:20:44,080 Speaker 1: we were finding them, like you know, pretending to I 439 00:20:44,119 --> 00:20:45,879 Speaker 1: just put cats everywhere, and I was like, okay, how 440 00:20:45,920 --> 00:20:47,879 Speaker 1: many cats do we see? I know that I secretly 441 00:20:47,920 --> 00:20:50,200 Speaker 1: hid two hundred cats in this neighborhood. How many cats 442 00:20:50,240 --> 00:20:52,320 Speaker 1: did we see? So that's exactly what I did, and 443 00:20:52,320 --> 00:20:54,560 Speaker 1: that was how we were able to say that, you know, 444 00:20:54,720 --> 00:20:58,440 Speaker 1: Kepler found two and a half thousand planets. From that, 445 00:20:58,520 --> 00:21:01,320 Speaker 1: we were able to infer that the aleaxy has billions 446 00:21:01,320 --> 00:21:03,760 Speaker 1: of planets. Given the numbers of stars we looked at 447 00:21:03,760 --> 00:21:05,800 Speaker 1: and the number of planets we found, the most exciting 448 00:21:05,800 --> 00:21:08,080 Speaker 1: discovery from the Kepler mission is that exer planets are 449 00:21:08,080 --> 00:21:10,480 Speaker 1: everywhere in our galaxy. So, just to force all the 450 00:21:10,560 --> 00:21:14,320 Speaker 1: conspiracy theorists, you injected fake data into a NASA mission, 451 00:21:14,320 --> 00:21:18,280 Speaker 1: but you told people you were injecting fake Yes. And 452 00:21:18,400 --> 00:21:20,199 Speaker 1: I had to jump through a lot of hoops to 453 00:21:20,280 --> 00:21:22,199 Speaker 1: do this, and it was quite funny. I had to 454 00:21:22,280 --> 00:21:25,600 Speaker 1: keep the simulated data on a separate server that was 455 00:21:25,680 --> 00:21:27,879 Speaker 1: never given access to the outside world. There was no 456 00:21:27,880 --> 00:21:30,480 Speaker 1: way to log into the server from the outside. And 457 00:21:30,520 --> 00:21:35,119 Speaker 1: even now years later, whenever somebody announces a new Kepler planet, 458 00:21:35,400 --> 00:21:37,640 Speaker 1: I have to go and double check that the period 459 00:21:37,840 --> 00:21:40,480 Speaker 1: and characteristics of this new planet aren't a match for 460 00:21:40,520 --> 00:21:42,560 Speaker 1: the you know, fake planet that I injected into that 461 00:21:42,640 --> 00:21:44,600 Speaker 1: light curve. So there's a lot of safeguarding to make 462 00:21:44,640 --> 00:21:48,240 Speaker 1: sure that the simulated data is never mistaken for real plants. Wow, 463 00:21:48,280 --> 00:21:50,200 Speaker 1: and how many cats have you found out there? So 464 00:21:50,280 --> 00:21:53,919 Speaker 1: we think that almost every star has planets around it. 465 00:21:54,000 --> 00:21:56,800 Speaker 1: The smaller the star, the more planets they have. So 466 00:21:57,080 --> 00:21:59,879 Speaker 1: m Dwarfs, which are the most ubiquitous star in our galaxy, 467 00:21:59,920 --> 00:22:02,280 Speaker 1: is seventy of the hundreds of billions of stars in 468 00:22:02,280 --> 00:22:05,800 Speaker 1: our galaxy. Endors we think that endors have multiple rocky 469 00:22:05,800 --> 00:22:08,760 Speaker 1: planets like Earth around them, which is wild because that 470 00:22:08,800 --> 00:22:11,400 Speaker 1: means there are hundreds of billions of rocky planets now galaxy, 471 00:22:11,520 --> 00:22:14,040 Speaker 1: which is so cool. That is really very cool. Yeah, 472 00:22:14,119 --> 00:22:17,520 Speaker 1: it's amazing. And you're sort of part of the James 473 00:22:17,520 --> 00:22:21,040 Speaker 1: Webb Space Telescope as well, right, So I am interested 474 00:22:21,080 --> 00:22:23,720 Speaker 1: in sideline to the James web Space Telescope. So I 475 00:22:23,760 --> 00:22:25,760 Speaker 1: haven't done a lot of atmosphere work myself. I do 476 00:22:25,840 --> 00:22:27,960 Speaker 1: more of the demographic stuff that Daniel was talking about, 477 00:22:28,080 --> 00:22:30,600 Speaker 1: working out how many cats we couldn't see because of 478 00:22:30,640 --> 00:22:32,679 Speaker 1: the cats we could see. So James Webb is more 479 00:22:32,720 --> 00:22:34,560 Speaker 1: going to be looking at the cats very carefully and 480 00:22:34,560 --> 00:22:36,480 Speaker 1: being like, Okay, this is a Siamese, and this is 481 00:22:36,480 --> 00:22:38,720 Speaker 1: a Burmese, and this is a Calico. And it uses 482 00:22:38,760 --> 00:22:40,840 Speaker 1: the transit method as well, right, it takes sort of 483 00:22:40,880 --> 00:22:44,600 Speaker 1: like giant pictures of the space. Yes, So, so the 484 00:22:44,600 --> 00:22:48,120 Speaker 1: transit method with what I was describing the transmission spectrum, 485 00:22:48,359 --> 00:22:51,560 Speaker 1: so as the starlight goes through the planet's atmosphere. We've 486 00:22:51,560 --> 00:22:53,919 Speaker 1: been able to do this with Hubble, and Hubble has 487 00:22:53,920 --> 00:22:56,120 Speaker 1: been able to give us really exquisite results. But we're 488 00:22:56,160 --> 00:22:59,000 Speaker 1: really pushing Hubble to the very, very very limits of 489 00:22:59,040 --> 00:23:00,760 Speaker 1: what it can do. And we're still looking at pretty 490 00:23:00,800 --> 00:23:04,400 Speaker 1: big planets like Neptune size planets and above. So with 491 00:23:04,520 --> 00:23:08,080 Speaker 1: James Web which is you know, three times bigger in radius, 492 00:23:08,080 --> 00:23:10,720 Speaker 1: so nearly ten times bigger in collecting area, we're going 493 00:23:10,800 --> 00:23:13,080 Speaker 1: to be able to look at smaller planets like Earth's 494 00:23:13,080 --> 00:23:15,679 Speaker 1: size planets and start to look at the atmospheres of those. 495 00:23:16,040 --> 00:23:18,200 Speaker 1: And that's you know, obviously I don't have to explain 496 00:23:18,240 --> 00:23:20,399 Speaker 1: why it's super interesting to look into the atmospheres of 497 00:23:20,440 --> 00:23:22,719 Speaker 1: Earth sized planets that we find. We want to know 498 00:23:22,880 --> 00:23:26,080 Speaker 1: how common are things like you know, carbon and oxygen 499 00:23:26,160 --> 00:23:30,040 Speaker 1: and nitrogen and phosphorus and methane and all of these 500 00:23:30,080 --> 00:23:33,600 Speaker 1: like super interesting based chemicals that we build life out of. 501 00:23:33,920 --> 00:23:36,520 Speaker 1: That's the next question. Now we know rocky planets are everywhere, 502 00:23:36,800 --> 00:23:39,879 Speaker 1: are rocky planets with the ingredients for life everywhere. That 503 00:23:39,920 --> 00:23:42,240 Speaker 1: would be super cool to know. That would be super cool. 504 00:23:42,280 --> 00:23:44,919 Speaker 1: And I also heard that you can sometimes look at 505 00:23:44,920 --> 00:23:47,320 Speaker 1: the weather in some of these exo planets by looking 506 00:23:47,320 --> 00:23:50,239 Speaker 1: at sort of the delays in the signals in the 507 00:23:50,240 --> 00:23:53,320 Speaker 1: way of moves around the Sun. Yes, exactly, so on 508 00:23:53,400 --> 00:23:55,639 Speaker 1: Earth One of the things we can see is the 509 00:23:55,680 --> 00:23:59,280 Speaker 1: phases of Venus. So Venus, you know, because it's interior 510 00:23:59,320 --> 00:24:01,920 Speaker 1: to us. Sometimes we see the full face of Venus 511 00:24:01,920 --> 00:24:04,280 Speaker 1: get illuminated, and sometimes we only see a phase of it. 512 00:24:04,800 --> 00:24:07,440 Speaker 1: We can do a similar thing with exoplanets around other 513 00:24:07,480 --> 00:24:10,200 Speaker 1: stars if we measure the brightness of the system very 514 00:24:10,320 --> 00:24:13,440 Speaker 1: very precisely. As the planet is orbiting around the star, 515 00:24:13,760 --> 00:24:16,520 Speaker 1: it actually starts reflecting light back towards us as it 516 00:24:16,560 --> 00:24:18,640 Speaker 1: goes behind the star. So we build what we call 517 00:24:18,680 --> 00:24:21,639 Speaker 1: a phase curve, and you can see things like you know, 518 00:24:21,800 --> 00:24:24,760 Speaker 1: jets and weather and spots and stuff coming and going, 519 00:24:24,960 --> 00:24:27,400 Speaker 1: and you know, it's very crude, but we can basically 520 00:24:27,440 --> 00:24:31,000 Speaker 1: reverse engineer these phase curves into maps of the surface, 521 00:24:31,080 --> 00:24:33,879 Speaker 1: and we can see variability. We can see that, you know, 522 00:24:33,920 --> 00:24:36,679 Speaker 1: the surfaces of these planets, the upper atmospheres, which is 523 00:24:36,680 --> 00:24:38,439 Speaker 1: really what we're looking at. The upper atmospheres of these 524 00:24:38,440 --> 00:24:41,119 Speaker 1: planets are changing, which is basically whether and then my 525 00:24:41,200 --> 00:24:43,040 Speaker 1: husband makes fun of me because he says, we're all 526 00:24:43,080 --> 00:24:47,040 Speaker 1: just becoming exo meteorologists, not astrophysicists, because we're es measuring 527 00:24:47,080 --> 00:24:48,879 Speaker 1: where there are other planets. But I still think that's 528 00:24:48,880 --> 00:24:51,480 Speaker 1: pretty amazing. Yeah, I can't wait for that telecast where 529 00:24:51,480 --> 00:24:54,600 Speaker 1: you're like throwing you know, sticky magnets with symbols of 530 00:24:54,680 --> 00:24:58,240 Speaker 1: ferns and clouds up on the planet excerpt. Yeah, and 531 00:24:58,320 --> 00:25:00,960 Speaker 1: tomorrow and fifty kancree e, get ready for some storms. 532 00:25:01,000 --> 00:25:03,399 Speaker 1: It's going to be a bad day. It's going to 533 00:25:03,440 --> 00:25:06,520 Speaker 1: be raining iron. So bring as the storms will be 534 00:25:06,520 --> 00:25:09,120 Speaker 1: bad tomorrow. You know, keep your umbrellas with you, your 535 00:25:09,160 --> 00:25:13,479 Speaker 1: diamond umbrellas exactly, your platinum umbrellas. And so the James 536 00:25:13,480 --> 00:25:16,160 Speaker 1: Webb can do this because it gathers more light because 537 00:25:16,200 --> 00:25:19,000 Speaker 1: as a larger collecting surface are also because you can 538 00:25:19,000 --> 00:25:21,760 Speaker 1: see different kinds of light. So that and those two things, 539 00:25:21,800 --> 00:25:24,000 Speaker 1: and also a third thing. So it's bigger. It's six 540 00:25:24,040 --> 00:25:25,879 Speaker 1: and a half meters as compared to Hubble, which is 541 00:25:26,240 --> 00:25:28,879 Speaker 1: to two and a half meters. It's got different wavelength 542 00:25:29,000 --> 00:25:32,280 Speaker 1: so it's more in the infrared and mid infrared. So 543 00:25:32,359 --> 00:25:35,000 Speaker 1: remember how I was talking about water, which absorbs at 544 00:25:35,000 --> 00:25:37,680 Speaker 1: one point four microns. That's in the near infrared. That's 545 00:25:37,680 --> 00:25:39,560 Speaker 1: not a wavelength of light we can see with our eyes. 546 00:25:39,960 --> 00:25:41,639 Speaker 1: That's a wavelength of light that you see with like 547 00:25:41,800 --> 00:25:44,120 Speaker 1: night vision goggles. It's one of the it's a signature 548 00:25:44,160 --> 00:25:45,919 Speaker 1: of heat and warmth in the infrared, so it's a 549 00:25:45,920 --> 00:25:48,320 Speaker 1: different wavelength. So that covers a whole bunch of the 550 00:25:48,359 --> 00:25:51,400 Speaker 1: really interesting molecules that we care about, like carbon dioxide 551 00:25:51,400 --> 00:25:54,520 Speaker 1: and carbon monoxide and water. And the third thing is 552 00:25:54,640 --> 00:25:58,440 Speaker 1: we've built these four just amazing instruments which are really 553 00:25:59,000 --> 00:26:02,200 Speaker 1: engineered to take advant iantage of James Webb's location in space. 554 00:26:02,240 --> 00:26:04,439 Speaker 1: It's wavelengths all of the interesting things that we're going 555 00:26:04,480 --> 00:26:05,879 Speaker 1: to look at, So we're going to be able to 556 00:26:05,920 --> 00:26:09,399 Speaker 1: get much higher resolution spectra, so be able to break 557 00:26:09,400 --> 00:26:12,840 Speaker 1: those wavelengths of light into into finer and fine negradations, 558 00:26:13,119 --> 00:26:15,159 Speaker 1: and then you can start to do all sorts of 559 00:26:15,200 --> 00:26:17,960 Speaker 1: interesting things like look at isotopes. You know, is it 560 00:26:18,040 --> 00:26:19,959 Speaker 1: heavy water or is it normal water? And what does 561 00:26:20,000 --> 00:26:21,879 Speaker 1: that mean about where that planet must have formed in 562 00:26:21,880 --> 00:26:24,880 Speaker 1: that protoplanetary disk, and was the water delivered later from 563 00:26:24,880 --> 00:26:27,600 Speaker 1: the outer Solar System? All this cool stuff. Once you 564 00:26:27,640 --> 00:26:30,680 Speaker 1: can start to get more detailed observations. Did you say 565 00:26:30,720 --> 00:26:33,080 Speaker 1: we can test the water in other planets? Yea. So 566 00:26:33,119 --> 00:26:34,680 Speaker 1: one of the things we could be able to do 567 00:26:34,800 --> 00:26:38,399 Speaker 1: if you have high enough resolution is measure isotopes. So 568 00:26:38,440 --> 00:26:41,480 Speaker 1: isotopes are basically, you know, molecules that have atoms that 569 00:26:41,520 --> 00:26:43,240 Speaker 1: have different amounts of neutrons in the center of the 570 00:26:43,280 --> 00:26:46,399 Speaker 1: same amount of protons. So we have something called heavy water, 571 00:26:46,680 --> 00:26:50,040 Speaker 1: which is basically water where instead of hydrogen and oxygen, 572 00:26:50,119 --> 00:26:54,040 Speaker 1: it's deuterium and oxygen. And we on Earth we use 573 00:26:54,119 --> 00:26:57,080 Speaker 1: heavy water to basically measure where we think the water 574 00:26:57,160 --> 00:27:00,240 Speaker 1: came from on Earth. So where Earth is right out 575 00:27:00,720 --> 00:27:03,680 Speaker 1: was too hot in the early Solar System for liquid water, 576 00:27:03,840 --> 00:27:05,560 Speaker 1: So we think that most of the water on Earth 577 00:27:05,640 --> 00:27:08,840 Speaker 1: was delivered from the outer Solar System by comets. So 578 00:27:08,960 --> 00:27:11,639 Speaker 1: during the formation of the Solar System was a really chaotic, 579 00:27:11,720 --> 00:27:14,880 Speaker 1: violent place. You know, planetisms are forming and smashing into 580 00:27:14,920 --> 00:27:18,320 Speaker 1: each other, orbits are changing and exchanging energy with each other, 581 00:27:18,480 --> 00:27:21,120 Speaker 1: and you have this huge cloud of material the Kuiper Belt, 582 00:27:21,119 --> 00:27:23,280 Speaker 1: and then outside of that the aort cloud, which are 583 00:27:23,320 --> 00:27:26,160 Speaker 1: just you're throwing stuff at the inner Solar System constantly. 584 00:27:26,359 --> 00:27:29,040 Speaker 1: So we think that the oceans on Earth largely came 585 00:27:29,119 --> 00:27:31,520 Speaker 1: from comets from the outer Solar System smashing into Earth 586 00:27:31,560 --> 00:27:34,399 Speaker 1: and delivering like these giant bowls of ice, Like commets 587 00:27:34,400 --> 00:27:36,640 Speaker 1: are just big bowls of ice and dirt basically. And 588 00:27:36,720 --> 00:27:38,320 Speaker 1: one of the ways we think this is true is 589 00:27:38,320 --> 00:27:40,639 Speaker 1: because we've been able to measure the isotopes of like 590 00:27:40,680 --> 00:27:42,960 Speaker 1: what rate of heavy water is there to normal water 591 00:27:43,240 --> 00:27:45,560 Speaker 1: on Earth versus the comets that we see. So if 592 00:27:45,600 --> 00:27:48,359 Speaker 1: you have precise enough spectra of exoplanet atmospheres, you can 593 00:27:48,359 --> 00:27:49,920 Speaker 1: start to do the same sort of thing, look at 594 00:27:50,000 --> 00:27:52,480 Speaker 1: isotopes and start to use that to map out where 595 00:27:52,480 --> 00:27:55,119 Speaker 1: you think things formed. There's a lot of open questions 596 00:27:55,160 --> 00:27:57,760 Speaker 1: about how planets form and how they migrate to where 597 00:27:57,760 --> 00:28:00,760 Speaker 1: we see them today. Well, testing the water on the planets, 598 00:28:00,800 --> 00:28:02,879 Speaker 1: you also said we can measure like how much CEO 599 00:28:02,920 --> 00:28:04,520 Speaker 1: two there is. Does that mean that we can tell 600 00:28:04,560 --> 00:28:07,520 Speaker 1: whether the water on those planets is like still water 601 00:28:07,760 --> 00:28:10,800 Speaker 1: or sparkling water? Yes, this is the peri a planet 602 00:28:10,840 --> 00:28:14,440 Speaker 1: over here. Is it flavored water like the big trend 603 00:28:14,480 --> 00:28:18,320 Speaker 1: right now? Almost certainly? Exactly. Well, and Nestlie probably owns 604 00:28:18,359 --> 00:28:20,760 Speaker 1: the water rights to all these planets already. Oh yeah, 605 00:28:20,960 --> 00:28:23,960 Speaker 1: almost certainly true. Was somewhere in the legal paperworkners like 606 00:28:24,160 --> 00:28:26,280 Speaker 1: this water and on all planets all their water to 607 00:28:27,440 --> 00:28:30,639 Speaker 1: So James Web has these amazing abilities because it's bigger, 608 00:28:30,760 --> 00:28:33,080 Speaker 1: because they can see deeper into the I R and 609 00:28:33,160 --> 00:28:35,400 Speaker 1: also because it has these new instruments. Can you say 610 00:28:35,440 --> 00:28:37,600 Speaker 1: something about the technology that was developed for the James 611 00:28:37,600 --> 00:28:41,000 Speaker 1: Web telescope specifically, I was reading about these incredible sensors 612 00:28:41,000 --> 00:28:44,600 Speaker 1: that they use to detect like individual photons. Yeah, so 613 00:28:44,760 --> 00:28:46,960 Speaker 1: that's actually one of been one of the big breakthroughs 614 00:28:46,960 --> 00:28:49,960 Speaker 1: in the last few decades. So you know, everybody nowadays 615 00:28:49,960 --> 00:28:52,959 Speaker 1: has really really fantastic c c D in their phone, right, 616 00:28:52,960 --> 00:28:55,280 Speaker 1: everybody just pulls out their phone and takes great images, 617 00:28:55,360 --> 00:28:57,880 Speaker 1: high resolution images. The goal for a long time has 618 00:28:57,880 --> 00:29:00,400 Speaker 1: been able to do this at other wavelengths. So c 619 00:29:00,560 --> 00:29:04,200 Speaker 1: CDs us a specific technology to turn visible light photons 620 00:29:04,280 --> 00:29:07,240 Speaker 1: into electrons and then you know, turn that into images. 621 00:29:07,320 --> 00:29:10,480 Speaker 1: But at other wavelengths that exchange doesn't happen the same way. 622 00:29:10,560 --> 00:29:13,720 Speaker 1: So there's a lot of interest in developing infrared detectors 623 00:29:13,760 --> 00:29:16,440 Speaker 1: and and ultra violet detectors that do as good a 624 00:29:16,520 --> 00:29:18,920 Speaker 1: job basically as your iPhone does. And that's been one 625 00:29:18,920 --> 00:29:21,160 Speaker 1: of the real advancements in the last few years. These 626 00:29:21,160 --> 00:29:25,200 Speaker 1: breakthroughs is making these infrared detectors that you know, can 627 00:29:25,240 --> 00:29:27,600 Speaker 1: serve the number of photons, which means you don't lose 628 00:29:27,640 --> 00:29:30,520 Speaker 1: any you can measure absolute numbers of photons, and that 629 00:29:30,640 --> 00:29:32,719 Speaker 1: do it at a high enough efficiency that you can 630 00:29:32,760 --> 00:29:35,640 Speaker 1: get really really good measurements even on very faint things, 631 00:29:35,640 --> 00:29:37,120 Speaker 1: which is a lot of what we're will go for. 632 00:29:37,280 --> 00:29:38,440 Speaker 1: I'm not going to be able to give you any 633 00:29:38,440 --> 00:29:41,160 Speaker 1: more technical details than that, because I didn't build any 634 00:29:41,200 --> 00:29:43,440 Speaker 1: of them. Well, that's all super fascinating, and we have 635 00:29:43,480 --> 00:29:46,200 Speaker 1: a lot more questions for your ex oplanet research, but 636 00:29:46,320 --> 00:30:01,280 Speaker 1: first we have to take a little break. All right, 637 00:30:01,360 --> 00:30:04,720 Speaker 1: we're back and we're talking to Dr Jesse Christensen, project 638 00:30:04,840 --> 00:30:08,400 Speaker 1: scientists of the NASA Exo Planet Archive. Like your consistent 639 00:30:08,480 --> 00:30:10,640 Speaker 1: I think you'ven sort of part of this whole sort 640 00:30:10,680 --> 00:30:14,000 Speaker 1: of revolution in exo planets. I mean, basically, before the 641 00:30:14,080 --> 00:30:17,400 Speaker 1: nineteen nine we didn't really have direct evidence or even 642 00:30:17,440 --> 00:30:20,280 Speaker 1: indirect evidence of planets and other stars. But this has 643 00:30:20,280 --> 00:30:22,360 Speaker 1: also to come about in the last thirty years. Right, 644 00:30:23,920 --> 00:30:26,360 Speaker 1: was the first discovery of a planet using this wobble 645 00:30:26,440 --> 00:30:29,280 Speaker 1: method around a star like our Sun. Actually a few 646 00:30:29,320 --> 00:30:33,320 Speaker 1: years before in nWo we had found planets around pulsars. 647 00:30:33,320 --> 00:30:36,120 Speaker 1: So a pulsar is what happens at the very end 648 00:30:36,120 --> 00:30:38,360 Speaker 1: of the life of a star that has puffed off, 649 00:30:38,360 --> 00:30:40,880 Speaker 1: its out of layers, and it's collapsed into a neutron 650 00:30:40,960 --> 00:30:44,160 Speaker 1: star and it's spinning super super super fast thousands of 651 00:30:44,200 --> 00:30:46,680 Speaker 1: times a second. And if you're lined up just right 652 00:30:46,720 --> 00:30:49,680 Speaker 1: to this spinning star, you actually see pulses of radiation 653 00:30:49,760 --> 00:30:52,600 Speaker 1: coming out thousands of times a second. So some people 654 00:30:52,640 --> 00:30:55,440 Speaker 1: who weren't actually hunting for extra planets, the extra planet 655 00:30:55,480 --> 00:30:58,160 Speaker 1: hunters rofire looking over looking at normal stars. So some 656 00:30:58,200 --> 00:31:00,959 Speaker 1: people who were looking at pulsars ound this pulsar that 657 00:31:01,040 --> 00:31:04,160 Speaker 1: was the pulses were sometimes coming early and sometimes coming late, 658 00:31:04,160 --> 00:31:06,480 Speaker 1: and sometimes coming early and sometimes coming late, and they 659 00:31:06,520 --> 00:31:09,560 Speaker 1: were like, what's happening, And they realized that there must 660 00:31:09,560 --> 00:31:12,560 Speaker 1: be something around this pulsar that was gravitationally pulling on it. 661 00:31:12,600 --> 00:31:15,120 Speaker 1: So sometimes the pulsar was moving towards us and sometimes 662 00:31:15,160 --> 00:31:16,760 Speaker 1: it was moving away. So there was kind of like 663 00:31:16,760 --> 00:31:19,160 Speaker 1: a doppler effect, like if you've ever had an ambulance 664 00:31:19,240 --> 00:31:21,040 Speaker 1: drive past you in the street and it's like, we 665 00:31:21,040 --> 00:31:24,360 Speaker 1: we this is what was happening to the pulsar, and 666 00:31:24,400 --> 00:31:27,080 Speaker 1: they realized it had planets, which was cool, but also 667 00:31:27,160 --> 00:31:29,440 Speaker 1: kind of a bit of a you know, side thing, 668 00:31:29,520 --> 00:31:32,080 Speaker 1: because pulsars are so strange and people were looking for 669 00:31:32,080 --> 00:31:34,560 Speaker 1: planets around stars like the Sun. So it's really only 670 00:31:34,600 --> 00:31:37,680 Speaker 1: been in the last thirty years that we've found planets, 671 00:31:38,000 --> 00:31:40,560 Speaker 1: and there's been such an explosion. Now we're about to 672 00:31:40,640 --> 00:31:42,320 Speaker 1: hit five thousand planets, which is going to be a 673 00:31:42,320 --> 00:31:44,760 Speaker 1: cool milestone that we're going to celebrate at the Extra 674 00:31:44,840 --> 00:31:47,520 Speaker 1: Plant Archive. But yeah, it's really the fact that technology 675 00:31:47,640 --> 00:31:50,320 Speaker 1: got us to the point where we could do this search. Yeah, 676 00:31:50,320 --> 00:31:53,120 Speaker 1: it's a pretty amazing technological feed And you sort of 677 00:31:53,120 --> 00:31:55,040 Speaker 1: described it as an explosion. Is that sort of what 678 00:31:55,080 --> 00:31:57,240 Speaker 1: you were expecting back in the nineties or has this 679 00:31:57,360 --> 00:31:59,120 Speaker 1: here am a number of exp planets? Has that been 680 00:31:59,160 --> 00:32:02,480 Speaker 1: a surprise? It's really interesting. So when I joined the 681 00:32:02,520 --> 00:32:04,880 Speaker 1: Extra Planet Hunt, which was in the mid two thousands 682 00:32:04,880 --> 00:32:08,360 Speaker 1: as a grad student, there were not very many planets 683 00:32:08,400 --> 00:32:10,320 Speaker 1: known yet, like it was still in the dozens to 684 00:32:10,600 --> 00:32:13,040 Speaker 1: a hundred or so, but they were being found, which 685 00:32:13,080 --> 00:32:15,080 Speaker 1: was why I was excited to do this as a 686 00:32:15,120 --> 00:32:16,800 Speaker 1: grad student and to search for them. And I will 687 00:32:16,840 --> 00:32:19,080 Speaker 1: say I spent four years searching for them using two 688 00:32:19,080 --> 00:32:21,440 Speaker 1: different surveys, and I never found a single one. But 689 00:32:21,480 --> 00:32:24,120 Speaker 1: they still gave me a PhD. So that's good. You 690 00:32:24,160 --> 00:32:26,240 Speaker 1: can get a PhD and planet hunting without ever having 691 00:32:26,320 --> 00:32:28,160 Speaker 1: found a planet. That's all right. I've been a particle 692 00:32:28,200 --> 00:32:30,400 Speaker 1: physicist for more than two decades and I've never found 693 00:32:30,400 --> 00:32:36,120 Speaker 1: a new particle. So I'm still looking. Well, Solidarity, Daniel Celibarity. 694 00:32:36,240 --> 00:32:39,600 Speaker 1: And then basically, as more and more surveys came online 695 00:32:39,840 --> 00:32:43,000 Speaker 1: and in, the telescopes got bigger and the instruments got better, 696 00:32:43,440 --> 00:32:46,200 Speaker 1: what we've really seen is an exponential rise. If you 697 00:32:46,240 --> 00:32:49,000 Speaker 1: plot the number of clients with time, it's it's exponential. 698 00:32:49,240 --> 00:32:51,120 Speaker 1: And I refer to this as Mama Jacks the law 699 00:32:51,120 --> 00:32:53,200 Speaker 1: because Eric Marma Jack was the first person to note 700 00:32:53,200 --> 00:32:56,600 Speaker 1: this exponential rise. And basically the doubling time you know, 701 00:32:56,760 --> 00:32:58,720 Speaker 1: you know how this More's law for computers where the 702 00:32:58,720 --> 00:33:00,920 Speaker 1: doubling time is like every two year. So the doubling 703 00:33:00,920 --> 00:33:03,600 Speaker 1: time for extra planets is about every two years or so, 704 00:33:03,600 --> 00:33:06,160 Speaker 1: so twenty seven months about. So what we're seeing is 705 00:33:06,160 --> 00:33:08,600 Speaker 1: the number of extra planets we know is doubling every 706 00:33:08,720 --> 00:33:11,640 Speaker 1: slightly more than two years. If you keep extrapolating, that 707 00:33:11,680 --> 00:33:13,920 Speaker 1: means we're going to hit a million planets by like 708 00:33:14,000 --> 00:33:17,040 Speaker 1: twenty thirty seven, which sounds ridiculous, but if you actually 709 00:33:17,080 --> 00:33:20,760 Speaker 1: look at the upcoming NASA and European Space Agency and 710 00:33:20,840 --> 00:33:23,920 Speaker 1: Chinese Space Agency missions. There's a lot of real estate 711 00:33:24,000 --> 00:33:25,840 Speaker 1: that we haven't searched yet that we will search in 712 00:33:25,880 --> 00:33:28,840 Speaker 1: the next few decades. So I'm actually not surprised if 713 00:33:28,840 --> 00:33:31,360 Speaker 1: we hit this million in the next fifteen years. And 714 00:33:31,400 --> 00:33:34,400 Speaker 1: these are just a million planets we've seen, right, The 715 00:33:34,440 --> 00:33:37,280 Speaker 1: number of planets out there is much much, much bigger. Exactly, 716 00:33:37,320 --> 00:33:39,200 Speaker 1: these are a million planets that we've been able to 717 00:33:39,280 --> 00:33:42,600 Speaker 1: individually detect and confirm in some way. And this is 718 00:33:42,640 --> 00:33:45,120 Speaker 1: the kind of thing that we can now explore and 719 00:33:45,320 --> 00:33:48,000 Speaker 1: you know, ask fun science questions about. But take us 720 00:33:48,000 --> 00:33:50,800 Speaker 1: sort of back again to the early nineties. Is this 721 00:33:50,920 --> 00:33:54,280 Speaker 1: what people anticipated that people know, given the technology that 722 00:33:54,360 --> 00:33:57,080 Speaker 1: was coming online, we would soon have all of these 723 00:33:57,080 --> 00:34:00,480 Speaker 1: planets or did people not really understand how many planets 724 00:34:00,520 --> 00:34:02,520 Speaker 1: were out there? You know, it was a really open 725 00:34:02,600 --> 00:34:05,360 Speaker 1: question because we had a sample size of one, right, 726 00:34:05,440 --> 00:34:08,160 Speaker 1: Like our star had planets around it, and there were 727 00:34:08,239 --> 00:34:10,920 Speaker 1: billions of stars in the galaxy. You know, a lot 728 00:34:10,920 --> 00:34:14,080 Speaker 1: of people had postulated that that there were planets, and 729 00:34:14,280 --> 00:34:16,279 Speaker 1: we just didn't know how many. We didn't know whether 730 00:34:16,400 --> 00:34:19,320 Speaker 1: things like the Solar System were rare and happened very rarely, 731 00:34:19,640 --> 00:34:22,359 Speaker 1: or whether they were ubiquitous or somewhere in the middle, 732 00:34:22,480 --> 00:34:25,560 Speaker 1: And from what we can tell, it seems like they're ubiquitous. 733 00:34:25,600 --> 00:34:28,680 Speaker 1: Like if you have the physics and the ingredients to 734 00:34:28,719 --> 00:34:31,040 Speaker 1: make stars, then you have the physics and the ingredients 735 00:34:31,040 --> 00:34:34,440 Speaker 1: to make planets. So I don't think it's a surprise 736 00:34:34,640 --> 00:34:38,040 Speaker 1: that we've found that they're ubiquitous, but I think it's 737 00:34:38,080 --> 00:34:41,000 Speaker 1: still an amazing achievement that we've been able to confirm 738 00:34:41,120 --> 00:34:43,880 Speaker 1: this intuition. I don't think anybody expected it would be 739 00:34:43,920 --> 00:34:47,960 Speaker 1: exponential in rise, but it really became a big industry 740 00:34:48,000 --> 00:34:50,640 Speaker 1: in astronomy to go hunting for exoplanets. Once we realized 741 00:34:50,640 --> 00:34:53,359 Speaker 1: that the technology had finally gotten past that threshold needed 742 00:34:53,360 --> 00:34:55,840 Speaker 1: to detect extraplanets, that everybody wanted to do it, and 743 00:34:55,880 --> 00:34:57,440 Speaker 1: it was the new hot thing. Is that what you 744 00:34:57,480 --> 00:35:00,959 Speaker 1: put in your business card the planet hunter or extra 745 00:35:01,000 --> 00:35:04,200 Speaker 1: planet hunter. I do usually call myself a planet hunter. 746 00:35:04,480 --> 00:35:08,520 Speaker 1: It makes me feel very Lara croft Ian. That's pretty cool. Yeah, 747 00:35:08,840 --> 00:35:10,719 Speaker 1: out of the thousands of the extra planets found, do 748 00:35:10,719 --> 00:35:14,200 Speaker 1: you have any favorites or any particularly weird ones that 749 00:35:14,280 --> 00:35:17,359 Speaker 1: we found. I do have a favorite system. So the 750 00:35:17,440 --> 00:35:20,160 Speaker 1: technology has gotten to the point where we have more 751 00:35:20,280 --> 00:35:22,560 Speaker 1: data than we can look at, and what that means 752 00:35:22,640 --> 00:35:25,319 Speaker 1: is a lot of us have turned to citizen science projects. 753 00:35:25,320 --> 00:35:28,560 Speaker 1: So citizen science projects are usually when scientists make a 754 00:35:28,560 --> 00:35:31,719 Speaker 1: whole bunch of data available online and ask people to 755 00:35:31,840 --> 00:35:34,880 Speaker 1: answer a pretty simple question about it, like help us 756 00:35:34,880 --> 00:35:38,839 Speaker 1: classify this, or mark a bad pixel, or translate this word, 757 00:35:39,160 --> 00:35:41,799 Speaker 1: or just do some simple repetitive tasks. It needs to 758 00:35:41,800 --> 00:35:44,480 Speaker 1: be done millions of times, and you know, we train 759 00:35:44,560 --> 00:35:47,000 Speaker 1: computers to do it too, but people are really really 760 00:35:47,000 --> 00:35:50,240 Speaker 1: good at seeing things that computers miss, Like our brain's 761 00:35:50,280 --> 00:35:54,120 Speaker 1: ability to do pattern matching is still unparalleled, Like it's 762 00:35:54,200 --> 00:35:56,680 Speaker 1: really important that we know the difference between a tiger 763 00:35:56,760 --> 00:35:59,120 Speaker 1: and a zebra, So you know, our brains are super 764 00:35:59,120 --> 00:36:02,160 Speaker 1: good at it. So in seventeen, my colleague Ian Crossfield 765 00:36:02,160 --> 00:36:04,200 Speaker 1: and I set up a citizen science project called Extra 766 00:36:04,239 --> 00:36:07,239 Speaker 1: Planet Explorers, where we had data from the Kepta Telescope 767 00:36:07,280 --> 00:36:09,440 Speaker 1: and we basically were just like, help us find planets 768 00:36:09,480 --> 00:36:11,200 Speaker 1: in it, like here are here are the data, look 769 00:36:11,200 --> 00:36:13,080 Speaker 1: and see what you see. And we were really really 770 00:36:13,120 --> 00:36:16,800 Speaker 1: lucky enough to get picked up by BBC Stargazing Live, 771 00:36:16,880 --> 00:36:21,800 Speaker 1: which is this like annual televised astronomy extravaganza like imagined 772 00:36:21,880 --> 00:36:24,680 Speaker 1: would Stock for Astronomy, where they do three nights of 773 00:36:24,760 --> 00:36:27,840 Speaker 1: primetime television, and they were interviewing astronomers around the world 774 00:36:27,840 --> 00:36:30,240 Speaker 1: and throwing from this telescope to that telescope, what's happening 775 00:36:30,239 --> 00:36:32,359 Speaker 1: over here. We're looking at Europa. So we were lucky 776 00:36:32,440 --> 00:36:34,719 Speaker 1: enough to get our project on that TV show and 777 00:36:34,760 --> 00:36:38,839 Speaker 1: we had ten thou volunteers look at planets, and within 778 00:36:38,960 --> 00:36:42,279 Speaker 1: fourty eight hours we had found this new system. It's 779 00:36:42,320 --> 00:36:44,920 Speaker 1: called K two one eight. And I'm going to pause 780 00:36:45,000 --> 00:36:49,080 Speaker 1: here and apologize because extra planet names are garbage. I'm sorry, 781 00:36:50,120 --> 00:36:52,920 Speaker 1: astronomers shouldn't be allowed to name anything. But the system 782 00:36:53,000 --> 00:36:56,160 Speaker 1: is called KT. It's got six planets in it. They're 783 00:36:56,200 --> 00:36:58,680 Speaker 1: all between the size of Earth and Neptune. The reason 784 00:36:58,760 --> 00:37:01,040 Speaker 1: I really love this system is that five of the 785 00:37:01,080 --> 00:37:04,279 Speaker 1: planets are in a resonant chain. So what that means 786 00:37:04,360 --> 00:37:07,239 Speaker 1: is that their orbital periods are related to each other 787 00:37:07,560 --> 00:37:10,680 Speaker 1: with very very simple integer ratios. And we see that 788 00:37:10,719 --> 00:37:13,720 Speaker 1: in our Solar system. So for instance, the Galilean moons 789 00:37:13,719 --> 00:37:16,000 Speaker 1: of Jupiter, three of them are in a one to 790 00:37:16,040 --> 00:37:18,959 Speaker 1: two to four ratio so for every you know, four 791 00:37:18,960 --> 00:37:21,600 Speaker 1: times io goes around, the next one goes around twice, 792 00:37:21,680 --> 00:37:23,319 Speaker 1: and for every two times that one goes around, the 793 00:37:23,320 --> 00:37:26,000 Speaker 1: next one goes around once. So they're all locked in 794 00:37:26,000 --> 00:37:28,200 Speaker 1: this resonance. And that's partly how you can get so 795 00:37:28,239 --> 00:37:31,359 Speaker 1: many moons like crammed so close together because they're in 796 00:37:31,360 --> 00:37:34,480 Speaker 1: this really stable formation and they're kept that way by 797 00:37:34,480 --> 00:37:38,160 Speaker 1: the resonans. So the system K has these five planets 798 00:37:38,160 --> 00:37:41,319 Speaker 1: that are all in a three to two resonans. So 799 00:37:41,400 --> 00:37:43,319 Speaker 1: the inner one goes around three times, the next one 800 00:37:43,360 --> 00:37:45,600 Speaker 1: goes around two times. For every three times that one 801 00:37:45,680 --> 00:37:47,879 Speaker 1: goes around, the next time go one goes around two times, 802 00:37:47,920 --> 00:37:51,080 Speaker 1: and so on. The reason that is cool is because 803 00:37:51,120 --> 00:37:53,960 Speaker 1: the three to two resonans, if you've ever studied music theory, 804 00:37:54,480 --> 00:37:57,600 Speaker 1: is the perfect fifth interval. So the first two notes 805 00:37:57,640 --> 00:38:00,880 Speaker 1: of Twinkle Twinkle Little Star. So this this system is 806 00:38:00,920 --> 00:38:03,960 Speaker 1: basically singing Twinkle Twinkle Little Star to us because they're 807 00:38:03,960 --> 00:38:06,440 Speaker 1: all in this this perfect fifth resonance. And it was 808 00:38:06,480 --> 00:38:08,680 Speaker 1: found by citizen scientists and we've got to like announce 809 00:38:08,719 --> 00:38:11,440 Speaker 1: it on live on TV. Was super cool and has 810 00:38:11,520 --> 00:38:13,920 Speaker 1: such a fun story. So that's that's my favorite one 811 00:38:13,920 --> 00:38:16,480 Speaker 1: that I've been able to publish. That's amazing. But I 812 00:38:16,480 --> 00:38:19,160 Speaker 1: don't know about letting the Internet choose the names. I 813 00:38:19,200 --> 00:38:23,600 Speaker 1: don't think they usually goes well, planet make planet face right. Yeah. Unfortunately, So, 814 00:38:23,719 --> 00:38:27,440 Speaker 1: the IAU, the International Astronomic Reunion, has actually had several 815 00:38:27,719 --> 00:38:32,640 Speaker 1: competitions worldwide competitions to let people name some small number 816 00:38:32,640 --> 00:38:35,319 Speaker 1: of exer planets. And they've been you know, they've been 817 00:38:35,360 --> 00:38:37,600 Speaker 1: good and bad ones. I like some of the suggestions, 818 00:38:37,600 --> 00:38:40,960 Speaker 1: some of them are strange. The problem is that the 819 00:38:41,040 --> 00:38:44,200 Speaker 1: IAU hasn't been able to get professional astronomers to adopt them. 820 00:38:44,200 --> 00:38:46,400 Speaker 1: Like if I've published this is KTI one thirty and 821 00:38:46,440 --> 00:38:48,360 Speaker 1: I've always called it KTI one thirty eight, if you 822 00:38:48,440 --> 00:38:51,680 Speaker 1: come along and call it, you know, liberty, and the 823 00:38:51,719 --> 00:38:54,280 Speaker 1: next one's called fraternity, and the next one is called whatever. 824 00:38:54,280 --> 00:38:55,759 Speaker 1: The third one is that I forget. But one of 825 00:38:55,760 --> 00:38:57,680 Speaker 1: them is the three French things. I'm not going to 826 00:38:57,760 --> 00:39:00,239 Speaker 1: call it those. I'm going to call it Katie yes again, Day, 827 00:39:00,280 --> 00:39:02,719 Speaker 1: that's right, thank you. So there are these names, but 828 00:39:02,760 --> 00:39:05,359 Speaker 1: they haven't stuck unfortunately. Well the real problem is going 829 00:39:05,400 --> 00:39:07,319 Speaker 1: to be when the aliens come from that planet and 830 00:39:07,360 --> 00:39:10,239 Speaker 1: they discover that we name they're planet K two, They're 831 00:39:10,239 --> 00:39:13,000 Speaker 1: gonna be pretty upset if you don't adopt their local name, 832 00:39:13,200 --> 00:39:15,640 Speaker 1: or maybe they like it, and this was exacerbated. So 833 00:39:15,840 --> 00:39:19,759 Speaker 1: just recently we announced the second exo moon candidate. So 834 00:39:19,800 --> 00:39:22,880 Speaker 1: this is a candidate moon around an exo planet around 835 00:39:22,880 --> 00:39:26,720 Speaker 1: another star. So the star is kept La seventeen o eight, 836 00:39:27,320 --> 00:39:30,080 Speaker 1: the planet is kept La seventeen oh eight B because 837 00:39:30,080 --> 00:39:32,719 Speaker 1: it's the first planet found around the star, and the 838 00:39:32,760 --> 00:39:36,239 Speaker 1: moon is kept La seventeen o eight B. I like 839 00:39:36,320 --> 00:39:39,880 Speaker 1: the Roman numeral little I for the first moon around 840 00:39:39,960 --> 00:39:42,600 Speaker 1: the first planet around the star, Keptla seventeen o eight. 841 00:39:42,960 --> 00:39:45,279 Speaker 1: And that's just about as unromantic as you can get 842 00:39:45,360 --> 00:39:47,919 Speaker 1: for for what could be the second moon we've ever 843 00:39:48,000 --> 00:39:51,239 Speaker 1: found around another planet, around another star. And why is 844 00:39:51,280 --> 00:39:53,880 Speaker 1: the first planet called B? Why isn't it called A 845 00:39:54,080 --> 00:39:57,960 Speaker 1: good question? We borrowed this from binary star nomenclature, where 846 00:39:58,080 --> 00:40:01,839 Speaker 1: the primary star is always A and then the secondary 847 00:40:01,880 --> 00:40:04,839 Speaker 1: star is always be capital A and capital B. So 848 00:40:04,880 --> 00:40:08,080 Speaker 1: when we started naming planets, we kept this convention that 849 00:40:08,120 --> 00:40:11,400 Speaker 1: the primary star is A and we started using little 850 00:40:11,440 --> 00:40:14,040 Speaker 1: B and little C for the planets. You get into 851 00:40:14,080 --> 00:40:16,719 Speaker 1: some really interesting corner cases here where you have like 852 00:40:16,760 --> 00:40:19,720 Speaker 1: a binary star system where both of the stars have planets, 853 00:40:19,760 --> 00:40:21,840 Speaker 1: because then you end up with you know, such and 854 00:40:21,880 --> 00:40:24,880 Speaker 1: such big A little B and such and such big B, 855 00:40:25,200 --> 00:40:27,279 Speaker 1: little B. And it's yeah, it's a lot, it's a 856 00:40:27,320 --> 00:40:30,440 Speaker 1: lot happening. It's enough to confuse the milky wee jeans 857 00:40:30,440 --> 00:40:33,359 Speaker 1: and all of us. Super cool. Let's get more into that, 858 00:40:33,480 --> 00:40:48,600 Speaker 1: but first let's take a quick break. And we are 859 00:40:48,640 --> 00:40:52,479 Speaker 1: back talking to Dr Jesse Christensen from the NASA Exo 860 00:40:52,520 --> 00:40:55,480 Speaker 1: Planet Archive. So we've observed all these solar systems, and 861 00:40:55,480 --> 00:40:57,640 Speaker 1: you said, we've found all these planets and some of 862 00:40:57,640 --> 00:41:00,200 Speaker 1: them are weird and fascinating and interesting. Isn't it true 863 00:41:00,200 --> 00:41:02,480 Speaker 1: also that we can only see certain kinds of planets, 864 00:41:02,480 --> 00:41:04,480 Speaker 1: Like you've talked about how we can see Jupiter, but 865 00:41:04,480 --> 00:41:06,400 Speaker 1: it'd be really hard for us to see Earth. Is 866 00:41:06,440 --> 00:41:09,759 Speaker 1: it possible for us to extrapolate to what those invisible 867 00:41:09,800 --> 00:41:12,520 Speaker 1: planets are, to what those solar systems actually look like 868 00:41:12,760 --> 00:41:14,719 Speaker 1: based on the few planets that we've seen. How do 869 00:41:14,760 --> 00:41:18,000 Speaker 1: we make those extrapolations and how uncertain are they? Yeah, 870 00:41:18,040 --> 00:41:20,480 Speaker 1: there's a lot going on in that question, and there's 871 00:41:20,480 --> 00:41:22,640 Speaker 1: a lot of people who are working hard on answering that. 872 00:41:22,920 --> 00:41:26,359 Speaker 1: So one thing I'll say is that we think that 873 00:41:26,400 --> 00:41:30,160 Speaker 1: planets like the Earth are common, but not because we've 874 00:41:30,200 --> 00:41:35,520 Speaker 1: actually found any confirmed robust detections and planets like the Earth. Unfortunately, 875 00:41:35,600 --> 00:41:38,440 Speaker 1: Kepler in the end didn't quite achieve the sensitivity it 876 00:41:38,520 --> 00:41:42,560 Speaker 1: needed to find earthlike planets. We do know that planets 877 00:41:42,600 --> 00:41:44,960 Speaker 1: just a little bit closer to the Sun than the 878 00:41:45,000 --> 00:41:47,760 Speaker 1: Earth is are common, and we do know that planets 879 00:41:47,800 --> 00:41:50,200 Speaker 1: just a bit bigger than the Earth are common. So 880 00:41:50,239 --> 00:41:53,480 Speaker 1: we do extrapolate, which is dangerous, always dangerous, but we 881 00:41:53,560 --> 00:41:56,560 Speaker 1: extrapolate from that to say that Earth sized planets at 882 00:41:56,560 --> 00:41:58,719 Speaker 1: the right distance from their stars to have liquid water 883 00:41:59,040 --> 00:42:02,319 Speaker 1: are common. So even that already is an extrapolation to 884 00:42:02,360 --> 00:42:05,600 Speaker 1: say that earthlike planets are common. We feel pretty good 885 00:42:05,640 --> 00:42:09,120 Speaker 1: about it, but not, you know, the best. So we 886 00:42:09,200 --> 00:42:12,480 Speaker 1: haven't actually found a Solar system analog yet, something that 887 00:42:12,560 --> 00:42:15,160 Speaker 1: has like in a rocky planets out to the distance 888 00:42:15,200 --> 00:42:17,759 Speaker 1: of Earth and Mars and then outer giant planets like 889 00:42:17,800 --> 00:42:20,120 Speaker 1: Jupiter Satin, you're in a synectric. We're just not there 890 00:42:20,120 --> 00:42:22,040 Speaker 1: with our precision yet. But we don't think that they 891 00:42:22,080 --> 00:42:24,520 Speaker 1: are uncommon given what we do know. And this comes 892 00:42:24,560 --> 00:42:27,360 Speaker 1: back to the invisible cats argument. We can do complicated 893 00:42:27,360 --> 00:42:31,200 Speaker 1: population analyses where we you know, fall back on Bayesian 894 00:42:31,239 --> 00:42:35,200 Speaker 1: statistics and prior knowledge to say, okay, if this system 895 00:42:35,280 --> 00:42:38,719 Speaker 1: had seven planets, and they were distributed in roughly the 896 00:42:38,760 --> 00:42:40,799 Speaker 1: same way as the planets of our solar system, how 897 00:42:40,840 --> 00:42:43,560 Speaker 1: many of them could we have seen? Um And for instance, 898 00:42:44,080 --> 00:42:46,960 Speaker 1: because the planets in our solar system aren't exactly lined 899 00:42:47,000 --> 00:42:49,799 Speaker 1: up in the same plane, there's no alien civilization that 900 00:42:49,840 --> 00:42:52,759 Speaker 1: could see all eight planets transit. You could only ever 901 00:42:52,760 --> 00:42:55,640 Speaker 1: see a subset and have to infer the larger sample. 902 00:42:55,760 --> 00:42:58,680 Speaker 1: And so infer is the is the important word there. 903 00:42:58,719 --> 00:43:00,759 Speaker 1: So again we have to put some prior. We have 904 00:43:00,800 --> 00:43:04,080 Speaker 1: to say we think that the mutual inclination, so the 905 00:43:04,200 --> 00:43:07,120 Speaker 1: spread in the orbital planes of the planets, should be 906 00:43:07,280 --> 00:43:10,400 Speaker 1: less than you know, let's say ten degrees, because if 907 00:43:10,440 --> 00:43:12,520 Speaker 1: you start to get to spread out, then they start 908 00:43:12,520 --> 00:43:15,160 Speaker 1: to interact with each other dynamically and become unstapid. But 909 00:43:15,200 --> 00:43:17,920 Speaker 1: again we're already making assumptions which might turn out later 910 00:43:17,960 --> 00:43:20,600 Speaker 1: to be wrong. So you put some prior on how 911 00:43:20,600 --> 00:43:22,759 Speaker 1: spread apart the planets could be. Then you look at 912 00:43:22,760 --> 00:43:25,760 Speaker 1: how many planets you've seen and say, okay, we've likely 913 00:43:25,840 --> 00:43:29,040 Speaker 1: missed seventy of the planets are in these systems, which 914 00:43:29,040 --> 00:43:31,319 Speaker 1: means that there are you know, three and a half 915 00:43:31,320 --> 00:43:33,920 Speaker 1: times as many. So that's kind of how we do it. 916 00:43:34,000 --> 00:43:36,520 Speaker 1: We do have to make some assumptions and they may 917 00:43:36,520 --> 00:43:39,560 Speaker 1: be wrong, but you know, if you give astronomers two planets, 918 00:43:39,560 --> 00:43:41,640 Speaker 1: they'll start to try and do statistics. So you're seeing 919 00:43:41,680 --> 00:43:44,160 Speaker 1: the reason we haven't seen other systems like our is 920 00:43:44,160 --> 00:43:46,120 Speaker 1: it not because we don't see them as you said, 921 00:43:46,160 --> 00:43:48,680 Speaker 1: we so far we can't have seen them or can't 922 00:43:48,680 --> 00:43:50,800 Speaker 1: be able to see them exactly. So some of the 923 00:43:50,880 --> 00:43:53,879 Speaker 1: NASA emissions are sensitive to planets close to the star, 924 00:43:54,040 --> 00:43:57,640 Speaker 1: so closer in than Earth, and some NASA emissions are 925 00:43:57,680 --> 00:44:00,800 Speaker 1: sensitive to planets further away, like the direct damaging planets 926 00:44:00,800 --> 00:44:03,000 Speaker 1: need to be very far away. And there's another technique 927 00:44:03,000 --> 00:44:05,120 Speaker 1: that I haven't talked about called micro lensing, which is 928 00:44:05,160 --> 00:44:08,040 Speaker 1: sensitive to planets that are far away. So the wobble 929 00:44:08,080 --> 00:44:10,160 Speaker 1: method that we talked about and the transit method are 930 00:44:10,200 --> 00:44:13,040 Speaker 1: both biased towards detecting planets close to the star, and 931 00:44:13,080 --> 00:44:15,520 Speaker 1: then the other methods are biased to finding planets far away. 932 00:44:16,040 --> 00:44:18,120 Speaker 1: What we haven't really been able to do a good job. 933 00:44:18,200 --> 00:44:21,799 Speaker 1: Yet is marry those results together and say, okay, we 934 00:44:21,840 --> 00:44:24,480 Speaker 1: have a complete census. We have a good idea what's 935 00:44:24,480 --> 00:44:26,520 Speaker 1: happening in the inner regions of the solar systems, and 936 00:44:26,560 --> 00:44:28,600 Speaker 1: we have a good idea what's happening in the outer regions. 937 00:44:28,760 --> 00:44:31,120 Speaker 1: And that's one of my big scientific goals for the 938 00:44:31,160 --> 00:44:33,799 Speaker 1: next decade because NASA is about to launch a new 939 00:44:33,800 --> 00:44:37,000 Speaker 1: mission called the Nancy Grace Roman Space Telescope, which will 940 00:44:37,040 --> 00:44:39,399 Speaker 1: happen in the second half of this decade, and it's 941 00:44:39,440 --> 00:44:41,759 Speaker 1: going to do a big micro lensing survey. So this 942 00:44:41,800 --> 00:44:44,759 Speaker 1: is this other detection technique of the galactic bulge, and 943 00:44:44,800 --> 00:44:46,600 Speaker 1: it will find a lot of planets in the our 944 00:44:46,760 --> 00:44:49,239 Speaker 1: solar systems. And then the question is, how do we 945 00:44:49,280 --> 00:44:51,759 Speaker 1: take the results from Kepler, which is a fantastic job 946 00:44:51,760 --> 00:44:54,560 Speaker 1: of mapping out inner solar systems, and the results from Roman, 947 00:44:54,800 --> 00:44:57,640 Speaker 1: which should do a fantastic job of mapping outer solar systems, 948 00:44:57,719 --> 00:45:00,359 Speaker 1: and you know, overlap them somewhere in the middle and 949 00:45:00,440 --> 00:45:03,160 Speaker 1: get a consistent answer for what does the whole Solar 950 00:45:03,200 --> 00:45:05,480 Speaker 1: system look like around these other stars. So that's one 951 00:45:05,520 --> 00:45:07,319 Speaker 1: of my big goals is to is to be able 952 00:45:07,360 --> 00:45:09,319 Speaker 1: to join the results from Kepler and Roman together so 953 00:45:09,360 --> 00:45:12,360 Speaker 1: that we can finally talk about Solar system analogs and 954 00:45:12,360 --> 00:45:15,200 Speaker 1: how common they might be. It's almost like planets the 955 00:45:15,239 --> 00:45:17,600 Speaker 1: size of the Earth are kind of hiding out there, 956 00:45:18,320 --> 00:45:20,319 Speaker 1: which is I guess a good thing. I guess if 957 00:45:20,360 --> 00:45:22,719 Speaker 1: we're trying to hide from evil aliens. Yeah, if you 958 00:45:22,760 --> 00:45:25,720 Speaker 1: look at the sensitivity curves of Kepler and what's predicted 959 00:45:25,760 --> 00:45:28,480 Speaker 1: for Roman Earth is like just snug like right in 960 00:45:28,520 --> 00:45:31,279 Speaker 1: the middle, just where they meet, Like, it's possible that 961 00:45:31,320 --> 00:45:33,839 Speaker 1: we still don't quite get there even with Roman Earth 962 00:45:33,960 --> 00:45:38,160 Speaker 1: is just really small. Unfortunately, I think we'll get there. 963 00:45:38,280 --> 00:45:41,320 Speaker 1: Another thing that NASA is planning is a really big 964 00:45:41,520 --> 00:45:45,200 Speaker 1: UV optical infrared mission for twenty or thirty years from now, 965 00:45:45,280 --> 00:45:47,719 Speaker 1: which will have one of these direct imaging instruments on it, 966 00:45:47,800 --> 00:45:49,879 Speaker 1: and the goal of that will be to actually take 967 00:45:49,920 --> 00:45:52,320 Speaker 1: a picture of a planet like the Earth around a 968 00:45:52,360 --> 00:45:54,920 Speaker 1: star like the Sun, which will be an incredible achievement 969 00:45:55,120 --> 00:45:57,319 Speaker 1: for humanity. Is that this sort of only way we'll 970 00:45:57,360 --> 00:45:59,799 Speaker 1: be able to see other Earth like planets like through 971 00:45:59,840 --> 00:46:02,440 Speaker 1: the pictures or do we just need a new kind 972 00:46:02,440 --> 00:46:05,479 Speaker 1: of technology or just improve the technology that we have? Oh? Yeah, 973 00:46:05,520 --> 00:46:08,879 Speaker 1: there's very very cool ideas for new technology that would 974 00:46:08,880 --> 00:46:11,359 Speaker 1: happen like on the order of fifty to a hundred years. 975 00:46:11,560 --> 00:46:15,000 Speaker 1: So for instance, one way you can get good resolution 976 00:46:15,280 --> 00:46:19,319 Speaker 1: is by making one telescope really really big, or by 977 00:46:19,320 --> 00:46:22,279 Speaker 1: getting two telescopes and putting them far apart and looking 978 00:46:22,320 --> 00:46:25,280 Speaker 1: at the same thing. And that's called interferometry. There's ideas 979 00:46:25,320 --> 00:46:27,440 Speaker 1: for an interferometer that would be the size of our 980 00:46:27,440 --> 00:46:30,520 Speaker 1: solar system, right like, you'd have some telescopes way out 981 00:46:30,560 --> 00:46:32,920 Speaker 1: in that direction and some telescopes way out in that direction, 982 00:46:33,120 --> 00:46:35,120 Speaker 1: and they would look at a planet around another star 983 00:46:35,520 --> 00:46:38,279 Speaker 1: and use the resolution that they gain from being you know, 984 00:46:38,840 --> 00:46:42,040 Speaker 1: many many au many many astronomic or units apart, which 985 00:46:42,040 --> 00:46:43,480 Speaker 1: is a distance from the Earth to the Sun to 986 00:46:43,480 --> 00:46:45,719 Speaker 1: be able to map the details. There's another really cool 987 00:46:46,239 --> 00:46:48,440 Speaker 1: idea concept for a future thing, which is to use 988 00:46:48,480 --> 00:46:52,280 Speaker 1: the Sun as a gravitational lens. So everything with mass 989 00:46:52,400 --> 00:46:55,640 Speaker 1: bends spacetime, right like you're bending spacetime right now as 990 00:46:55,640 --> 00:46:58,440 Speaker 1: you sit there. So the Sun is bending spacetime. And 991 00:46:58,480 --> 00:47:01,680 Speaker 1: that's what magnifying glasses, right, They bend light so that 992 00:47:01,719 --> 00:47:03,600 Speaker 1: it comes together in a certain way to make it 993 00:47:03,600 --> 00:47:06,040 Speaker 1: look like things are closer. So you could imagine putting 994 00:47:06,040 --> 00:47:08,200 Speaker 1: a telescope on the other side of the Sun and 995 00:47:08,320 --> 00:47:11,960 Speaker 1: using the Sun as a gravitational lens to magnify a 996 00:47:12,080 --> 00:47:14,480 Speaker 1: background star and planets such that you could see it 997 00:47:14,520 --> 00:47:16,879 Speaker 1: in more detail. Like how cool is that? That would 998 00:47:16,880 --> 00:47:20,240 Speaker 1: be super awesome. Basically, you're talking about building a lens 999 00:47:20,320 --> 00:47:21,960 Speaker 1: the size of the Sun, so you're just gathering a 1000 00:47:22,000 --> 00:47:24,600 Speaker 1: huge amount of light which allows us to see dimmer 1001 00:47:24,640 --> 00:47:27,000 Speaker 1: objects and to magnify them as that. Right, you're using 1002 00:47:27,040 --> 00:47:29,840 Speaker 1: the Sun as a giant lens because it's bending spacetime 1003 00:47:29,880 --> 00:47:33,000 Speaker 1: the way a normal you know, glass lens bends air 1004 00:47:33,080 --> 00:47:35,520 Speaker 1: and light. You guys are really thinking big. Now you've 1005 00:47:35,520 --> 00:47:37,359 Speaker 1: got James web up there. You're like, wow, we can 1006 00:47:37,400 --> 00:47:41,560 Speaker 1: do anything. Yeah. The fact that that deployment sequence is 1007 00:47:41,600 --> 00:47:45,480 Speaker 1: going so well is super super relieving. Like so many 1008 00:47:45,520 --> 00:47:47,680 Speaker 1: people have worked on James Webb for so many years, 1009 00:47:48,080 --> 00:47:51,040 Speaker 1: and there were so many moving carts, but so far, 1010 00:47:51,280 --> 00:47:54,040 Speaker 1: fingers crossed, all of the big things have happened and 1011 00:47:54,160 --> 00:47:57,480 Speaker 1: happened the right way. So go, James Webb. Can you 1012 00:47:57,480 --> 00:47:59,560 Speaker 1: also give us something of a map of like where 1013 00:47:59,680 --> 00:48:02,520 Speaker 1: we have looked for these planets. I know that some 1014 00:48:02,640 --> 00:48:05,080 Speaker 1: of these things are capable of seeing planets close by, 1015 00:48:05,160 --> 00:48:07,440 Speaker 1: and some of them are capable of seeing things far away. 1016 00:48:07,719 --> 00:48:10,480 Speaker 1: How we explored our entire galaxy as much as we can. 1017 00:48:10,680 --> 00:48:14,520 Speaker 1: Oh yeah, so actually we really haven't. So our galaxy, 1018 00:48:14,520 --> 00:48:17,480 Speaker 1: our Milky Way galaxy, is what we call a grand spiral, 1019 00:48:17,640 --> 00:48:19,400 Speaker 1: so if you could look down on it, it's got 1020 00:48:19,440 --> 00:48:22,399 Speaker 1: these lovely huge spiral arms, and we're just like out 1021 00:48:22,440 --> 00:48:24,920 Speaker 1: in the burbs. So the galaxy itself is about a 1022 00:48:24,960 --> 00:48:27,839 Speaker 1: hundred thousand light years all the way across, and where 1023 00:48:27,880 --> 00:48:30,960 Speaker 1: about thirty thousand light years from the middle, So we're 1024 00:48:31,040 --> 00:48:34,040 Speaker 1: kind of, yeah, just out on the edges. Basically, basically 1025 00:48:34,080 --> 00:48:36,200 Speaker 1: almost all of the planets that we found so far 1026 00:48:36,480 --> 00:48:39,960 Speaker 1: are within a few thousand light years, So remember a 1027 00:48:40,000 --> 00:48:41,920 Speaker 1: thirty thousand light is to the center of the galaxy. 1028 00:48:42,200 --> 00:48:45,120 Speaker 1: We've really only searched like this little bubble around us 1029 00:48:45,160 --> 00:48:47,600 Speaker 1: out we call what we call the local solar neighborhood. 1030 00:48:47,640 --> 00:48:49,840 Speaker 1: And you know, the five thousand or so planets that 1031 00:48:49,880 --> 00:48:53,399 Speaker 1: we found so far are almost all very close to us. 1032 00:48:53,760 --> 00:48:57,880 Speaker 1: Now I say very close spaces really really really really 1033 00:48:57,920 --> 00:49:00,359 Speaker 1: really really really big even just a few you light 1034 00:49:00,440 --> 00:49:05,000 Speaker 1: years away. With our current technology, basically inconceivable for ust 1035 00:49:05,040 --> 00:49:07,439 Speaker 1: to visit. We can send messages and they will still 1036 00:49:07,440 --> 00:49:10,520 Speaker 1: take years to get there. To our closest star, Alpha Centaur, 1037 00:49:10,760 --> 00:49:13,359 Speaker 1: which is four light years away, it would still take 1038 00:49:13,400 --> 00:49:14,880 Speaker 1: us four years to get a message to even the 1039 00:49:14,920 --> 00:49:17,879 Speaker 1: closest star. So while we have only searched our local 1040 00:49:17,880 --> 00:49:20,720 Speaker 1: stellar neighborhood, that is still a really big blob of space. 1041 00:49:21,360 --> 00:49:23,560 Speaker 1: So now come back and picture the whole galaxy again 1042 00:49:24,120 --> 00:49:26,640 Speaker 1: and think about this tiny circle off to one side 1043 00:49:26,640 --> 00:49:29,719 Speaker 1: that we've been able to explore, and now think about 1044 00:49:29,760 --> 00:49:33,200 Speaker 1: what else could be in galaxy. That's what keeps me hunting, right, Like, 1045 00:49:33,280 --> 00:49:36,319 Speaker 1: that's so cool. It's such a big space. And as 1046 00:49:36,360 --> 00:49:38,759 Speaker 1: our instruments get better and our technology gets better and 1047 00:49:38,800 --> 00:49:41,120 Speaker 1: our ideas get better, we're just going to be able 1048 00:49:41,120 --> 00:49:42,920 Speaker 1: to explore more and more and more of it. And 1049 00:49:43,040 --> 00:49:45,880 Speaker 1: is there a possibility that our local solar neighborhood is 1050 00:49:45,920 --> 00:49:49,240 Speaker 1: like unrepresentative? You know, we have this history in science 1051 00:49:49,239 --> 00:49:52,560 Speaker 1: and especially in physics of generalizing from our experience and 1052 00:49:52,560 --> 00:49:55,600 Speaker 1: then discovering, oops, that was a mistake. Is it possible 1053 00:49:55,600 --> 00:49:58,399 Speaker 1: that what we've learned about solar systems is only applicable 1054 00:49:58,520 --> 00:50:01,520 Speaker 1: to this little neighborhood and that or more planets first 1055 00:50:01,520 --> 00:50:03,799 Speaker 1: star somewhere else, or fewer planets. So do you think 1056 00:50:03,800 --> 00:50:06,120 Speaker 1: it's likely that what we've learned so far is true 1057 00:50:06,160 --> 00:50:08,720 Speaker 1: across the Milky Way? Oh, it is such a good question. 1058 00:50:08,880 --> 00:50:11,680 Speaker 1: And now I'm gonna share something. So my research group 1059 00:50:11,760 --> 00:50:14,520 Speaker 1: just met this morning and a post stuff that I'm 1060 00:50:14,520 --> 00:50:16,279 Speaker 1: working with showed us a plot. And this is like 1061 00:50:16,280 --> 00:50:19,120 Speaker 1: a brand new plot where we're trying to map out 1062 00:50:19,400 --> 00:50:21,960 Speaker 1: how the occurrence rate of planets, how common planets are, 1063 00:50:22,360 --> 00:50:25,759 Speaker 1: changes with properties of the galaxy. And he showed us 1064 00:50:25,800 --> 00:50:28,279 Speaker 1: this plot this morning that showed that a current rate 1065 00:50:28,280 --> 00:50:32,600 Speaker 1: of planets might decrease with your distance from the galactic plane. 1066 00:50:32,920 --> 00:50:35,720 Speaker 1: So remember I said, we're in a big spiral. Now 1067 00:50:35,800 --> 00:50:37,720 Speaker 1: almost all of the stars are in a big disc, 1068 00:50:38,000 --> 00:50:39,879 Speaker 1: but there are some stars that are out of that disk, 1069 00:50:40,040 --> 00:50:41,799 Speaker 1: so they're out of the plane of the galaxy. And 1070 00:50:41,840 --> 00:50:43,560 Speaker 1: so this is literally just he showed us this plot 1071 00:50:43,560 --> 00:50:45,160 Speaker 1: this morning and we were just sat there like, cool, 1072 00:50:45,360 --> 00:50:47,439 Speaker 1: what does it mean? So it could be the fact 1073 00:50:47,600 --> 00:50:49,760 Speaker 1: that as you get out of the plane of the galaxy, 1074 00:50:49,960 --> 00:50:52,160 Speaker 1: it's harder and harder to make planets. And now the 1075 00:50:52,160 --> 00:50:54,920 Speaker 1: immediate question is why is that. We know that stars 1076 00:50:54,960 --> 00:50:57,840 Speaker 1: out of the plane of the galaxy have fewer heavy elements. 1077 00:50:57,960 --> 00:50:59,960 Speaker 1: So you know how I said dust and gas earlier. 1078 00:51:00,120 --> 00:51:02,799 Speaker 1: They have less dust compared to gas. Maybe that means 1079 00:51:02,800 --> 00:51:04,799 Speaker 1: it's harder for them to make planets. We also know 1080 00:51:04,880 --> 00:51:06,759 Speaker 1: that stars out of the plane of the galaxy are 1081 00:51:06,800 --> 00:51:08,680 Speaker 1: older than the stars in the plane of the galaxy, 1082 00:51:08,680 --> 00:51:10,680 Speaker 1: which is where most of the star birth happens, than 1083 00:51:10,760 --> 00:51:12,799 Speaker 1: the stellar nurseries are almost all on the plane. What 1084 00:51:12,840 --> 00:51:14,640 Speaker 1: does age have to do? Why was it harder to 1085 00:51:14,680 --> 00:51:17,239 Speaker 1: make planets eleven billion years ago than it is now? 1086 00:51:17,360 --> 00:51:19,760 Speaker 1: So these are all like super interesting questions that literally 1087 00:51:19,800 --> 00:51:22,320 Speaker 1: we're trying to answer right now. There are good reasons 1088 00:51:22,360 --> 00:51:24,920 Speaker 1: to believe that, you know, planet formation might be different 1089 00:51:24,920 --> 00:51:27,200 Speaker 1: in different parts of the galaxy. For instance, as you 1090 00:51:27,200 --> 00:51:29,240 Speaker 1: get closer and closer to the center of the galaxy, 1091 00:51:29,600 --> 00:51:32,319 Speaker 1: the stellar density gets more and more crowded and the 1092 00:51:32,360 --> 00:51:35,920 Speaker 1: stellar radiation gets more and more concentrated, so it might 1093 00:51:35,960 --> 00:51:38,600 Speaker 1: be harder to make certain types of planets. It might 1094 00:51:38,640 --> 00:51:41,120 Speaker 1: be harder to keep planets once you've made them, as 1095 00:51:41,200 --> 00:51:43,160 Speaker 1: you know, especially as you get closer and closer to 1096 00:51:43,239 --> 00:51:45,799 Speaker 1: the center and things start to get really crowded. So yeah, 1097 00:51:45,840 --> 00:51:49,040 Speaker 1: there's a there's a lot of questions about how planet 1098 00:51:49,080 --> 00:51:51,919 Speaker 1: occurrence might change as you move around the galaxy. So 1099 00:51:52,080 --> 00:51:54,439 Speaker 1: you know, imagine like the first season of a TV 1100 00:51:54,520 --> 00:51:57,400 Speaker 1: show where you're just looking around your local neighborhood and 1101 00:51:57,400 --> 00:51:59,920 Speaker 1: you're like cool, and then the second season is like, oh, 1102 00:52:00,280 --> 00:52:02,560 Speaker 1: this is just like one neighborhood in a huge city, 1103 00:52:02,800 --> 00:52:05,880 Speaker 1: So we're just starting to peek outside our neighborhood and 1104 00:52:05,920 --> 00:52:08,160 Speaker 1: see what could be happening. Not all milky regions are 1105 00:52:08,280 --> 00:52:11,280 Speaker 1: maybe me the same way, exactly exactly. So for instance, 1106 00:52:11,520 --> 00:52:14,080 Speaker 1: life on Earth, if you look at the equations for 1107 00:52:14,280 --> 00:52:17,439 Speaker 1: the chemical energy gradients that describe life on Earth, there's 1108 00:52:17,480 --> 00:52:20,200 Speaker 1: like heaps of carbon atoms and heaps of hydrogen atoms, 1109 00:52:20,239 --> 00:52:23,440 Speaker 1: and heaps of oxygen atom and one phosphorus. So like 1110 00:52:23,520 --> 00:52:25,880 Speaker 1: the literally the rate of life on Earth is governed 1111 00:52:25,880 --> 00:52:28,279 Speaker 1: by how much phosphorus we have, And like, is that 1112 00:52:28,360 --> 00:52:30,920 Speaker 1: true elsewhere in the galaxy? And do other places in 1113 00:52:30,960 --> 00:52:33,200 Speaker 1: the galaxy have enough phosphorus to make life if they 1114 00:52:33,280 --> 00:52:36,920 Speaker 1: use the same chemical energy gradients. That's super interesting and important. 1115 00:52:36,960 --> 00:52:38,840 Speaker 1: You know what, I just pieced it together. So we 1116 00:52:38,880 --> 00:52:41,840 Speaker 1: call people from Norway Norwegians. That's where Milky Way, and 1117 00:52:41,840 --> 00:52:44,960 Speaker 1: then we would be Milky Wegians. Exactly. You got it. 1118 00:52:45,000 --> 00:52:50,919 Speaker 1: You're there. It only took me an hour. It took 1119 00:52:50,960 --> 00:52:54,440 Speaker 1: me eighteen hours. Someone asked what we should call them, 1120 00:52:54,440 --> 00:52:56,480 Speaker 1: and I kind of went away and was like, huh, 1121 00:52:56,680 --> 00:52:58,560 Speaker 1: And then I pondered for a while, and eventually I 1122 00:52:58,640 --> 00:53:00,719 Speaker 1: landed on Milky Regions. And it took you one hour, 1123 00:53:00,760 --> 00:53:03,760 Speaker 1: It took me much longer. See, sometimes astronomers are good 1124 00:53:03,800 --> 00:53:07,520 Speaker 1: at choosing names. There you go, I'll take one one victory. 1125 00:53:07,520 --> 00:53:09,839 Speaker 1: So let me ask you to speculate a little bit. 1126 00:53:09,880 --> 00:53:12,080 Speaker 1: There's this big dark part of the galaxy we haven't 1127 00:53:12,080 --> 00:53:14,600 Speaker 1: seen in so many planets which are currently invisible to us. 1128 00:53:14,760 --> 00:53:17,319 Speaker 1: That suggests that there might be surprises out there. Right. 1129 00:53:17,320 --> 00:53:19,280 Speaker 1: It could just be that it looks the way we expect, 1130 00:53:19,480 --> 00:53:21,880 Speaker 1: but you know, the universe seems to always have surprises 1131 00:53:21,920 --> 00:53:23,640 Speaker 1: for us in store. Can you give us a sense 1132 00:53:23,680 --> 00:53:26,880 Speaker 1: for the sort of range of possibilities? Like what kinds 1133 00:53:26,880 --> 00:53:29,480 Speaker 1: of things might we discover when we turn on these 1134 00:53:29,520 --> 00:53:32,160 Speaker 1: new eyeballs and explore the rest of the galaxy. Yeah, like, 1135 00:53:32,200 --> 00:53:33,680 Speaker 1: what do you think we're going to know in twenty 1136 00:53:33,760 --> 00:53:36,120 Speaker 1: or fifty years. Well, one thing I hope we know 1137 00:53:36,200 --> 00:53:39,239 Speaker 1: in twenty or fifty years is how many Earth like 1138 00:53:39,400 --> 00:53:42,840 Speaker 1: planets are there that we can actually see with our instruments. 1139 00:53:42,880 --> 00:53:46,680 Speaker 1: That would be amazing in terms of what's the unknown unknowns. 1140 00:53:46,960 --> 00:53:50,080 Speaker 1: One thing that's surprised us a lot is the fact 1141 00:53:50,080 --> 00:53:52,640 Speaker 1: that the most common kind of planet we have found 1142 00:53:53,239 --> 00:53:56,040 Speaker 1: is between the size of Earth and Neptune. So in 1143 00:53:56,080 --> 00:53:58,640 Speaker 1: our Solar system there's a big jump. We have all 1144 00:53:58,640 --> 00:54:00,920 Speaker 1: the little planets up to this size of Earth, and 1145 00:54:00,920 --> 00:54:02,759 Speaker 1: then we have all the giant planets that start at 1146 00:54:02,800 --> 00:54:05,520 Speaker 1: Neptune and go up. But there's a gap. So Neptune 1147 00:54:05,560 --> 00:54:07,719 Speaker 1: is about four times the size of Earth, and in 1148 00:54:07,719 --> 00:54:10,520 Speaker 1: our Solar system there's nothing in that gap. As we 1149 00:54:10,600 --> 00:54:13,640 Speaker 1: have explored the galaxy around us, the most common kind 1150 00:54:13,680 --> 00:54:16,279 Speaker 1: of planet we have found is in that gap. It's 1151 00:54:16,280 --> 00:54:18,400 Speaker 1: bigger than Earth but smaller than Neptune. And so do 1152 00:54:18,400 --> 00:54:20,560 Speaker 1: you call it a super Earth or a mini Neptune, 1153 00:54:20,640 --> 00:54:22,440 Speaker 1: or do you have some other crazy name for it. 1154 00:54:22,800 --> 00:54:24,960 Speaker 1: We actually call them both of those things, and kind 1155 00:54:24,960 --> 00:54:26,960 Speaker 1: of depends on what science case you're trying to make. 1156 00:54:27,200 --> 00:54:29,719 Speaker 1: So super Earth's we think are up to maybe one 1157 00:54:29,760 --> 00:54:31,920 Speaker 1: and a half to one point six times the size 1158 00:54:31,920 --> 00:54:34,279 Speaker 1: of the Earth and then above that. We think that 1159 00:54:34,320 --> 00:54:38,480 Speaker 1: they're compositionally more like mini neptunes, but we actually don't know. 1160 00:54:38,840 --> 00:54:41,840 Speaker 1: And one of the big open questions is could they 1161 00:54:41,880 --> 00:54:44,560 Speaker 1: actually be just a different kind of planet, not just 1162 00:54:44,719 --> 00:54:47,440 Speaker 1: a big rock or a small ice school, but like 1163 00:54:47,440 --> 00:54:50,880 Speaker 1: an ocean world, like something that's you know, predominantly water. 1164 00:54:51,320 --> 00:54:54,840 Speaker 1: Is there some other you know, configuration of compositions of 1165 00:54:54,960 --> 00:54:58,160 Speaker 1: rock and iron and ice shells and different kinds of 1166 00:54:58,200 --> 00:55:01,080 Speaker 1: ice and water that can be to these planets. So 1167 00:55:01,280 --> 00:55:03,440 Speaker 1: one of the things I hope we know in twenty 1168 00:55:03,520 --> 00:55:05,840 Speaker 1: to fifty years is what our super earths and what 1169 00:55:05,920 --> 00:55:08,200 Speaker 1: our many neptunes like you know, are they a new 1170 00:55:08,239 --> 00:55:09,839 Speaker 1: type of planet that we don't have an our Solar 1171 00:55:09,880 --> 00:55:13,360 Speaker 1: system because at the moment, only having a bulk composition, 1172 00:55:13,440 --> 00:55:15,120 Speaker 1: so we know the size and we know the mass, 1173 00:55:15,160 --> 00:55:16,799 Speaker 1: it doesn't give us a good idea of how the 1174 00:55:16,880 --> 00:55:20,439 Speaker 1: mass breaks down inside that sphere basically, so we don't 1175 00:55:20,440 --> 00:55:22,480 Speaker 1: know yet, and I'm hoping we will know. The things 1176 00:55:22,520 --> 00:55:24,680 Speaker 1: that have surprised us a lot so far besides this 1177 00:55:24,760 --> 00:55:27,880 Speaker 1: discovery of this new type of planet, it has a 1178 00:55:27,880 --> 00:55:32,200 Speaker 1: lot to do with configurations. So for instance, finding giant 1179 00:55:32,239 --> 00:55:34,799 Speaker 1: planets like Jupiter right next to the star that orbit 1180 00:55:34,800 --> 00:55:37,080 Speaker 1: in just a few days. So the very first kinds 1181 00:55:37,120 --> 00:55:39,480 Speaker 1: of planets we found were these hot Jupiters we call 1182 00:55:39,520 --> 00:55:41,840 Speaker 1: them because they're Jupiters heated up to thousands of degrees. 1183 00:55:42,000 --> 00:55:44,680 Speaker 1: So finding hot Jupiters was a big surprise. Finding these 1184 00:55:44,719 --> 00:55:48,360 Speaker 1: really compact systems of planets like KTE eight but I described, 1185 00:55:48,400 --> 00:55:50,640 Speaker 1: which is a series of resonant planets in this chain. 1186 00:55:51,160 --> 00:55:53,480 Speaker 1: That's also been really new because you know, in our 1187 00:55:53,480 --> 00:55:56,040 Speaker 1: solar system there's nothing between the Sun and mercury. In 1188 00:55:56,160 --> 00:55:59,040 Speaker 1: K two, there's six planets that are closer to the 1189 00:55:59,080 --> 00:56:02,280 Speaker 1: star than Mercury is. They're all really packed in type. 1190 00:56:02,360 --> 00:56:05,439 Speaker 1: So finding these dynamically packed systems. So as we start 1191 00:56:05,480 --> 00:56:09,960 Speaker 1: to explore more space, which includes younger stars, it includes 1192 00:56:10,320 --> 00:56:14,120 Speaker 1: more metal pour stars with with less heavy elements, finding 1193 00:56:14,120 --> 00:56:16,879 Speaker 1: out what kinds of planets they make and how soon 1194 00:56:16,920 --> 00:56:19,279 Speaker 1: they make them. So, for instance, the reason we look 1195 00:56:19,280 --> 00:56:21,000 Speaker 1: at young stars and look for planets is to try 1196 00:56:21,000 --> 00:56:23,080 Speaker 1: and work out how long does it take to make 1197 00:56:23,080 --> 00:56:26,680 Speaker 1: a planet, because different planet formation theories predict different time scales, 1198 00:56:26,880 --> 00:56:29,279 Speaker 1: So we're hoping to like look at young stars and 1199 00:56:29,320 --> 00:56:31,520 Speaker 1: work out how quickly they make planets, and it might 1200 00:56:31,560 --> 00:56:33,759 Speaker 1: and you know, we'll probably be surprised. We'll probably find 1201 00:56:33,760 --> 00:56:36,040 Speaker 1: out they make them super fast, and we'll be like, Okay. 1202 00:56:36,120 --> 00:56:38,080 Speaker 1: So there's lots of lots of things I expect to 1203 00:56:38,120 --> 00:56:40,640 Speaker 1: be surprised by in the next twenty to fifty years, 1204 00:56:40,680 --> 00:56:43,480 Speaker 1: but mostly new types of planets in new types of 1205 00:56:43,520 --> 00:56:47,520 Speaker 1: configurations is what I expect. That's awesome me. One last question, Daniel, Yeah, 1206 00:56:47,560 --> 00:56:50,400 Speaker 1: if you find a combination Neptune Earth, why didn't you 1207 00:56:50,440 --> 00:56:52,840 Speaker 1: call it a nept Earth. I like Neptinia as the 1208 00:56:52,840 --> 00:56:56,600 Speaker 1: mini Neptune substitute. It sounds like a cocktail. And in fact, 1209 00:56:56,640 --> 00:56:58,960 Speaker 1: many of US astronomers have gotten together at more than 1210 00:56:59,000 --> 00:57:02,680 Speaker 1: one conference to drink eptiniece and the next morning you 1211 00:57:02,680 --> 00:57:03,839 Speaker 1: have to wake up and drink a lot of hot 1212 00:57:03,920 --> 00:57:08,600 Speaker 1: jupiters to recover. Right, exactly right? Mean? One last question, 1213 00:57:08,680 --> 00:57:11,320 Speaker 1: Dr Pritsinson, what's it like to be a planet hunter? 1214 00:57:11,600 --> 00:57:13,920 Speaker 1: Like when you discover a new planet? Can you describe 1215 00:57:13,920 --> 00:57:16,840 Speaker 1: that feeling? Sure? So there's this this this phrase you 1216 00:57:16,920 --> 00:57:19,760 Speaker 1: might have heard this saying, you know where the generation 1217 00:57:19,800 --> 00:57:22,560 Speaker 1: that was born too late to explore Earth but too 1218 00:57:22,560 --> 00:57:25,400 Speaker 1: soon to explore space, and I feel in just this 1219 00:57:25,480 --> 00:57:28,840 Speaker 1: incredibly privileged position. I feel like I get to explore space. 1220 00:57:28,960 --> 00:57:32,520 Speaker 1: I get to discover new worlds around other stars. And so, 1221 00:57:32,680 --> 00:57:34,840 Speaker 1: you know the long nights of the telescope, you know 1222 00:57:34,840 --> 00:57:37,720 Speaker 1: it's three am, the instrument has been misbehaving. You have 1223 00:57:37,840 --> 00:57:40,080 Speaker 1: this one candidate you really really want to get a 1224 00:57:40,080 --> 00:57:43,200 Speaker 1: good luck at the sky is finally clear. You get 1225 00:57:43,240 --> 00:57:44,760 Speaker 1: the data and you look at it and you see 1226 00:57:45,120 --> 00:57:47,400 Speaker 1: it's a planet. And you know, I always just like 1227 00:57:47,440 --> 00:57:48,800 Speaker 1: sit back and put my hands on my face and 1228 00:57:48,800 --> 00:57:52,800 Speaker 1: I'm like, yes, okay, yes, great, awesome, And then you 1229 00:57:52,840 --> 00:57:54,440 Speaker 1: move on to the next candidate because you only have 1230 00:57:54,480 --> 00:57:55,960 Speaker 1: like two hours before the sun is going to come up, 1231 00:57:56,000 --> 00:57:57,880 Speaker 1: and some of them won't turn out to be real planets, 1232 00:57:57,920 --> 00:58:00,440 Speaker 1: but you know, there's always this moment where you get 1233 00:58:00,440 --> 00:58:03,120 Speaker 1: to sit there and be like I know something that 1234 00:58:03,160 --> 00:58:05,560 Speaker 1: no one else knows right now, Like I know that 1235 00:58:05,600 --> 00:58:07,480 Speaker 1: this is a planet, and you just get to savor 1236 00:58:07,480 --> 00:58:10,160 Speaker 1: it for a second and just be like that's really cool. 1237 00:58:10,240 --> 00:58:12,120 Speaker 1: And then I usually send like an all caps email 1238 00:58:12,160 --> 00:58:15,640 Speaker 1: to my collaborators We've got one, because you might be 1239 00:58:15,680 --> 00:58:17,720 Speaker 1: the only person in the galaxy that knows about that 1240 00:58:17,760 --> 00:58:20,400 Speaker 1: planet or the universe. I'm never sure whether I'm more 1241 00:58:20,480 --> 00:58:24,560 Speaker 1: scared of us being alone or not being alone? Right, Like, 1242 00:58:24,680 --> 00:58:26,240 Speaker 1: is it a scary thought to be the only one 1243 00:58:26,280 --> 00:58:28,120 Speaker 1: who knows about it? Or is it a scary thought 1244 00:58:28,120 --> 00:58:30,600 Speaker 1: to not be the only one who knows about it? 1245 00:58:30,600 --> 00:58:32,920 Speaker 1: Sounds like you need another and a tiny yes, right, 1246 00:58:32,960 --> 00:58:35,320 Speaker 1: that'll help. I'll settle it all right. Well, thanks very 1247 00:58:35,400 --> 00:58:37,320 Speaker 1: much for coming on and answering all of our very 1248 00:58:37,320 --> 00:58:40,560 Speaker 1: serious and very silly questions about exo planet futures. It's 1249 00:58:40,560 --> 00:58:42,640 Speaker 1: been a pleasure. Yeah, the pleasure is behind. Thank you 1250 00:58:42,720 --> 00:58:53,040 Speaker 1: so much. Thanks for listening, and remember that Daniel and 1251 00:58:53,120 --> 00:58:56,440 Speaker 1: Jorge explain the universe is a production of I Heart Radio. 1252 00:58:56,680 --> 00:58:59,280 Speaker 1: For more podcast from my Heart Radio, or visit the 1253 00:58:59,360 --> 00:59:02,720 Speaker 1: I Heart a new Apple, Apple Podcasts, or wherever you 1254 00:59:02,800 --> 00:59:04,320 Speaker 1: listen to your favorite shows.