WEBVTT 1 00:00:03.399 --> 00:00:07.719 Welcome to Bedtime Astronomy. Explore the wonders of the cosmos 2 00:00:07.759 --> 00:00:12.279 with our soothing Bedtime Astronomie podcast. Each episode offers a 3 00:00:12.359 --> 00:00:16.320 gentle journey through the stars, planets, and beyond, perfect for 4 00:00:16.399 --> 00:00:20.239 unwinding after a long day. Let's travel through the mysteries 5 00:00:20.239 --> 00:00:22.440 of the universe as you drift off into a peaceful 6 00:00:22.480 --> 00:00:23.800 slumber under the night sky. 7 00:00:26.960 --> 00:00:29.719 If you want to find the next Earth, like a 8 00:00:29.839 --> 00:00:33.679 literal second home for humanity out there in the galaxy, yeah, 9 00:00:33.719 --> 00:00:36.439 the absolute worst place you could look is right around 10 00:00:36.479 --> 00:00:38.399 a star that looks exactly like our son. 11 00:00:38.640 --> 00:00:42.200 I mean, which sounds completely backward, right, because for decades 12 00:00:42.240 --> 00:00:43.600 that was the whole strategy, right. 13 00:00:43.600 --> 00:00:46.280 You assume you wanted a carbon copy of our solar system. Yeah, 14 00:00:46.320 --> 00:00:49.679 a nice, stable yellow Sun and a rocky little planet 15 00:00:49.719 --> 00:00:51.520 just sitting at the exact right distance exactly. 16 00:00:51.560 --> 00:00:57.399 But the data has completely forced us to basically tear 17 00:00:57.479 --> 00:01:00.399 up that playbook. Finding a twin of Earth around a 18 00:01:00.439 --> 00:01:02.399 twin of the Sun is just well, with our current 19 00:01:02.479 --> 00:01:03.679 tach it's practically. 20 00:01:03.280 --> 00:01:06.640 Impossible, which is so frustrating. But that's why today we're 21 00:01:06.640 --> 00:01:09.799 talking about venturing into I guess you could call it 22 00:01:09.799 --> 00:01:11.120 the cosmic graveyard. 23 00:01:11.319 --> 00:01:12.760 Yeah, that's a good way to put it. 24 00:01:12.840 --> 00:01:15.680 We're looking at these things called failed stars, and we're 25 00:01:15.680 --> 00:01:18.079 getting into all this because of a Canadian space mission 26 00:01:18.079 --> 00:01:21.239 called POOAA, which is launching in twenty twenty nine. 27 00:01:21.319 --> 00:01:24.359 Right, and POUAIT is totally abandoning the blinding light of 28 00:01:24.359 --> 00:01:28.359 those bright yellow suns. It is a highly optimized, really 29 00:01:28.400 --> 00:01:31.879 aggressive strategy to search in the shadows basically. 30 00:01:32.120 --> 00:01:35.159 Okay, so let's lay out the scoreboard first, because the 31 00:01:35.239 --> 00:01:41.640 numbers here they really tell a super frustrating story for astronomers. Oh, absolutely, right, Now, 32 00:01:41.799 --> 00:01:47.480 humanity has confirmed nearly six thousand, three hundred exoplanets. 33 00:01:46.719 --> 00:01:49.439 Which is just a staggering number to even think about. 34 00:01:49.519 --> 00:01:53.359 It's massive. Just pause and think about that. Over six 35 00:01:53.480 --> 00:01:57.799 thousand alien worlds orbiting other stars that we know exists 36 00:01:57.879 --> 00:02:01.840 for sure. But out of that huge catalog, only two 37 00:02:01.879 --> 00:02:05.200 hundred and twenty three are actually designated as terrestrial. 38 00:02:04.799 --> 00:02:08.000 Right, meaning they're rocky planets with a solid surface like 39 00:02:08.120 --> 00:02:09.080 Earth or Mars. 40 00:02:09.159 --> 00:02:10.680 Yeah, it's two hundred and twenty three. So you look 41 00:02:10.680 --> 00:02:12.639 at a ratio like that and it's like, what roughly 42 00:02:12.639 --> 00:02:13.719 three percent roughly. 43 00:02:13.919 --> 00:02:14.680 Yeah, it's so. 44 00:02:14.719 --> 00:02:17.639 Easy to jump to the conclusion that rocky planets are 45 00:02:17.680 --> 00:02:19.759 just as super rare anomaly in the universe. 46 00:02:19.960 --> 00:02:22.400 But that is a total trap. You really can't look 47 00:02:22.439 --> 00:02:23.000 at it that way. 48 00:02:23.120 --> 00:02:24.639 Really, why not, Because. 49 00:02:24.319 --> 00:02:27.280 The vast majority of those six thousand worlds are gas 50 00:02:27.319 --> 00:02:31.840 giants or ice giants. There are these massive, bloated planets 51 00:02:31.840 --> 00:02:34.199 that don't even have a solid surface, right, So. 52 00:02:34.120 --> 00:02:37.159 We're talking about places like Jupiter or Neptune. 53 00:02:37.039 --> 00:02:41.159 Exactly, environments where the atmospheric pressure is so intense it 54 00:02:41.199 --> 00:02:45.080 would you know, it would literally crush anything long before 55 00:02:45.400 --> 00:02:47.560 it ever reached some hypothetical core. 56 00:02:47.759 --> 00:02:50.520 So the fact that we have thousands of gas giants 57 00:02:51.080 --> 00:02:52.919 and barely any rocky ones. 58 00:02:52.840 --> 00:02:55.400 It tells us practically nothing about what's actually out there 59 00:02:55.439 --> 00:02:58.159 in the universe, But it tells us absolutely everything about 60 00:02:58.159 --> 00:02:59.879 the limitations of our own telescopes. 61 00:03:00.199 --> 00:03:04.759 Okay, so it's classic selection bias. It's like, uh, if 62 00:03:04.800 --> 00:03:07.879 you drag a huge fishing net through the ocean, but 63 00:03:07.879 --> 00:03:10.240 the net has these massive holes in it right right, 64 00:03:10.319 --> 00:03:12.800 you pull it up, You're like, wow, the ocean only 65 00:03:12.840 --> 00:03:16.840 contains giant tuna, but really all the small fish just 66 00:03:16.879 --> 00:03:18.039 slipped right through the gaps. 67 00:03:18.280 --> 00:03:21.039 That's a perfect analogy. The tools we rely on are 68 00:03:21.080 --> 00:03:24.199 heavily biased toward finding the loudest, biggest things in the room. 69 00:03:24.680 --> 00:03:27.879 Okay, so unpack that for us. Why are our tools 70 00:03:27.919 --> 00:03:28.560 so biased? 71 00:03:28.719 --> 00:03:31.280 Well, it comes down to the physics of exoplanet detection. 72 00:03:31.719 --> 00:03:34.360 Planets don't emit their own light, right, at least not 73 00:03:34.400 --> 00:03:37.120 in the visible spectrum. They only reflect the light of 74 00:03:37.159 --> 00:03:38.039 their host star. 75 00:03:38.319 --> 00:03:40.120 Right, there's just bouncing light back at us. 76 00:03:40.400 --> 00:03:43.960 Yeah, So direct imaging, like actually pointing a telescope and 77 00:03:43.960 --> 00:03:47.840 taking a photograph of a planet, is unbelievably difficult. It's 78 00:03:47.840 --> 00:03:50.479 like trying to photograph a firefly buzzing right next to. 79 00:03:50.439 --> 00:03:53.039 A lighthouse from like fifty miles away. 80 00:03:53.120 --> 00:03:56.960 Exactly, the glare from the lighthouse the star just completely 81 00:03:57.360 --> 00:03:59.960 washes out the tiny speck of light from the planet. 82 00:04:00.520 --> 00:04:02.080 So if we can't just take a picture of them, 83 00:04:02.120 --> 00:04:03.879 how are we finding thousands of them? 84 00:04:04.120 --> 00:04:07.360 We have to rely on indirect methods we observe the 85 00:04:07.360 --> 00:04:10.719 effect that the planet has on its star. Historically, we 86 00:04:10.879 --> 00:04:14.000 leaned really heavily on something called the radial velocity method. 87 00:04:14.120 --> 00:04:17.560 A radio velocity Okay, what is that? In plain English? 88 00:04:17.639 --> 00:04:21.800 It's basically measuring a microscopic wobble as a planet orbits 89 00:04:21.839 --> 00:04:24.560 a star. It's gravity actually tugs on the star a 90 00:04:24.600 --> 00:04:26.720 little bit and makes the star wobble back and forth 91 00:04:26.759 --> 00:04:27.199 in space. 92 00:04:27.399 --> 00:04:29.480 Oh wow, so the star is actually moving. 93 00:04:29.399 --> 00:04:32.079 Just a tiny bit. Yeah. And obviously a massive bulky 94 00:04:32.120 --> 00:04:35.120 gas giant like Jupiter is going to yank on that 95 00:04:35.160 --> 00:04:37.519 star a lot harder than a tiny speck of rock 96 00:04:37.600 --> 00:04:38.120 like Earthwood. 97 00:04:38.199 --> 00:04:39.240 So the wabble is bigger. 98 00:04:39.360 --> 00:04:41.959 The wabble is much bigger. The Doppler shift in the 99 00:04:41.959 --> 00:04:45.600 starlight is way more pronounced, and our telescopes can catch 100 00:04:45.639 --> 00:04:46.879 that signal pretty easily. 101 00:04:47.079 --> 00:04:50.920 Okay, that makes total sense. Big planet equals big wobble 102 00:04:51.480 --> 00:04:55.839 equals easy to spot. But what about the other method, 103 00:04:56.120 --> 00:04:57.800 the one that really blew the doors open. 104 00:04:57.839 --> 00:04:59.199 You're talking about the transit method. 105 00:04:59.279 --> 00:05:01.720 Yeah, the transmit because that's what the Kepler mission used. 106 00:05:01.639 --> 00:05:05.279 Right exactly. Kepler changed everything. And the transit method is 107 00:05:05.480 --> 00:05:08.439 conceptually super simple. It's just an eclipse. 108 00:05:08.480 --> 00:05:10.600 So a planet just passes in front of the star. 109 00:05:10.600 --> 00:05:14.079 Right, It passes directly between our telescope and the host star, 110 00:05:14.519 --> 00:05:17.439 and it blocks a tiny, tiny fraction of the starlight. 111 00:05:17.519 --> 00:05:19.319 Okay, but let's run the numbers on that, because I 112 00:05:19.319 --> 00:05:22.160 feel like people underestimate how hard this is if we 113 00:05:22.199 --> 00:05:23.600 take an Earth sun analog. 114 00:05:23.759 --> 00:05:24.519 Okay, let's do it. 115 00:05:24.839 --> 00:05:28.000 Let's say there's an alien astronomer hundreds of light years 116 00:05:28.040 --> 00:05:30.879 away staring at our Sun and hoping to catch the 117 00:05:30.920 --> 00:05:34.680 Earth transitting. Right, how much light does the Earth actually block? 118 00:05:34.959 --> 00:05:37.759 About zero point zero percent. 119 00:05:37.680 --> 00:05:39.160 One hundredth of one percent. 120 00:05:39.160 --> 00:05:43.240 Exactly one hundredth of one percent of the Sun's total light. 121 00:05:43.720 --> 00:05:47.560 And here's the kicker. That dip only happens once a year. 122 00:05:47.879 --> 00:05:50.000 Because our orbit takes a year, right. 123 00:05:50.040 --> 00:05:52.759 And the transit itself only lasts for a few hours. 124 00:05:52.959 --> 00:05:55.920 That is insane. It's literally like trying to detect a 125 00:05:55.959 --> 00:05:59.480 single moth flying in front of a stadium spotlight from 126 00:05:59.560 --> 00:06:02.160 miles of miles away. Yes, and you're doing it purely 127 00:06:02.199 --> 00:06:05.079 by measuring the drop in the spotlights overall glare. 128 00:06:04.879 --> 00:06:07.319 Which is incredibly hard. And to make it worse, you 129 00:06:07.360 --> 00:06:09.920 can't just spot it once to actually confirm an orbit. 130 00:06:09.959 --> 00:06:11.480 You need to see multiple transits. 131 00:06:11.600 --> 00:06:14.000 You're waiting years and years just to verify a. 132 00:06:13.959 --> 00:06:16.800 Signal, years, and you're looking for a signal that is 133 00:06:16.879 --> 00:06:19.120 barely distinguishable from background static. 134 00:06:19.399 --> 00:06:22.120 The static. Let's talk about the static, because the stars 135 00:06:22.160 --> 00:06:24.040 themselves are not making this easy for us. 136 00:06:24.360 --> 00:06:27.959 Not at all. Stars are not uniform perfectly static light bulbs. 137 00:06:27.959 --> 00:06:31.399 They are violently churning spheres of plasma. Right, They have 138 00:06:31.600 --> 00:06:35.240 massive sunspots that rotate into view, and those sunspots are dark, 139 00:06:35.279 --> 00:06:38.040 so they block light and actually mimic a planetary transit. 140 00:06:38.279 --> 00:06:41.319 Oh so a sunspot can look like a fake planet exactly. 141 00:06:41.600 --> 00:06:44.879 Plus they have solar flares and internal pulsations that cause 142 00:06:44.920 --> 00:06:47.519 their brightness to wildly fluctuate all the time. 143 00:06:47.639 --> 00:06:50.600 So you're trying to find a zero point zero one 144 00:06:50.639 --> 00:06:54.759 percent dip caused by an Earth sized planet amidst all 145 00:06:54.800 --> 00:06:57.399 this chaotic, boiling stellar noise. 146 00:06:57.480 --> 00:07:00.120 It's an immense challenge. But conversely, if you're a looking 147 00:07:00.120 --> 00:07:02.480 at a Jupiter sized planet around a sun like star, 148 00:07:03.160 --> 00:07:05.160 it blocks about one whole percent of. 149 00:07:05.079 --> 00:07:07.000 The light, which is huge by comparison. 150 00:07:07.160 --> 00:07:10.639 Right, that is a massive, unmistakable signal compared to the 151 00:07:10.680 --> 00:07:11.279 noise floor. 152 00:07:11.399 --> 00:07:13.639 Okay, so knowing all of this, the need for a 153 00:07:13.680 --> 00:07:16.959 specialized tool becomes super obvious. If the fishing net has 154 00:07:17.000 --> 00:07:19.319 holes that are too big, you don't just keep casting 155 00:07:19.319 --> 00:07:21.079 it over and over hoping for a miracle. 156 00:07:21.160 --> 00:07:23.360 No, you build an entirely different net. 157 00:07:23.120 --> 00:07:26.160 Which brings us to the entire driving philosophy behind the 158 00:07:26.160 --> 00:07:30.600 POET mission. Yes, poet T it stands for Photometric Observations 159 00:07:30.600 --> 00:07:34.439 of Exoplanet Transits. Like we said, it's a Canadian microsatellite 160 00:07:34.480 --> 00:07:37.240 launching in twenty twenty nine and its sole purpose is 161 00:07:37.240 --> 00:07:40.000 to find Earth size and super Earth exoplanets. 162 00:07:40.040 --> 00:07:42.639 But the brilliant thing is they aren't trying to achieve 163 00:07:42.680 --> 00:07:45.600 this by building some monstrously huge mirror. 164 00:07:45.560 --> 00:07:48.399 Right, because building a bigger camera to stare at the 165 00:07:48.399 --> 00:07:52.319 same stadium spotlight doesn't actually solve the fundamental contrast problem, 166 00:07:52.399 --> 00:07:53.040 right exactly. 167 00:07:53.079 --> 00:07:56.360 The genius of po is that it changes the spotlight itself. 168 00:07:56.399 --> 00:07:58.639 Okay, explain that how do you change the spotlight? 169 00:07:58.759 --> 00:08:02.040 Instead of looking at G type yellow dorks like our sun, 170 00:08:02.319 --> 00:08:05.879 the mission is targeting what astronomers classify as ultracool dwarfs. 171 00:08:05.959 --> 00:08:06.680 Ultracool dwarfs. 172 00:08:06.720 --> 00:08:09.560 Okay, So, going back to your analogy, if you swap 173 00:08:09.600 --> 00:08:13.079 out that massive stadium spotlight for a dim, little. 174 00:08:12.800 --> 00:08:14.800 Desk lamp, oh I see where this is going. 175 00:08:14.879 --> 00:08:17.680 Right, and that same moth flies in front of the 176 00:08:17.720 --> 00:08:23.720 desk lamp, the percentage of light that gets blocked absolutely skyrockets. 177 00:08:23.040 --> 00:08:25.120 Because the background light is so much smaller. 178 00:08:25.240 --> 00:08:29.680 Exactly, the fractional dip in brightness goes from that imperceptible 179 00:08:30.079 --> 00:08:33.759 zero point zero one percent to a highly measurable one 180 00:08:33.799 --> 00:08:35.200 percent or even more. 181 00:08:35.799 --> 00:08:38.759 That is such a clever hack. So let's really dig 182 00:08:38.799 --> 00:08:42.320 into what makes a star an ultra cool dwarf, because 183 00:08:42.399 --> 00:08:44.519 targeting the runts of the stellar litter is just a 184 00:08:44.559 --> 00:08:45.480 fascinating approach. 185 00:08:45.519 --> 00:08:47.600 To me, it's the best strategy we have right now. 186 00:08:47.639 --> 00:08:50.360 So when we look at the stellar classification system, it's 187 00:08:50.440 --> 00:08:53.960 essentially a temperature scale, right, that also correlates with mass 188 00:08:54.000 --> 00:08:54.639 and size. 189 00:08:54.759 --> 00:08:57.879 That's right, Our sun is a G type star. K 190 00:08:57.960 --> 00:09:00.240 type stars are a little bit smaller, they're cooler, and 191 00:09:00.279 --> 00:09:02.559 they glow with a slightly orange hue. 192 00:09:02.879 --> 00:09:04.720 Okay, and M type M. 193 00:09:04.639 --> 00:09:07.759 Type stars are the red dwarfs. They're even smaller and 194 00:09:07.799 --> 00:09:10.120 cooler still. But then you get to the bottom of 195 00:09:10.120 --> 00:09:12.759 the barrel, the brown dwarfs. 196 00:09:12.399 --> 00:09:15.519 And these are the ones Pew is specifically hunting. The 197 00:09:15.559 --> 00:09:19.759 literature always refers to brown dwarfs as failed stars. Yes, 198 00:09:19.840 --> 00:09:22.440 what does that actually mean? What are the physical mechanism 199 00:09:22.559 --> 00:09:23.519 of a star failing? 200 00:09:23.879 --> 00:09:26.120 To understand the failure, you really have to look at 201 00:09:26.120 --> 00:09:28.519 how a star is born. In the first place, A 202 00:09:28.600 --> 00:09:32.759 star begins as this massive collapsing cloud of hydrogen, gas 203 00:09:32.759 --> 00:09:33.279 and dust. 204 00:09:33.519 --> 00:09:35.559 Right, gravity is just pulling everything together. 205 00:09:35.759 --> 00:09:40.000 Exactly as gravity pulls all that material inward, the pressure 206 00:09:40.039 --> 00:09:42.960 and the temperature at the very core begin to styrocket, 207 00:09:43.279 --> 00:09:45.919 and if the collapse in cloud has enough mass, the 208 00:09:45.960 --> 00:09:48.559 core temperature reaches a critical threshold, which. 209 00:09:48.399 --> 00:09:50.480 Is what like millions of degrees. 210 00:09:50.399 --> 00:09:54.440 Around ten million degrees celsius. At that point, the kinetic 211 00:09:54.600 --> 00:09:58.399 energy of the hydrogen atoms is so ridiculously high that 212 00:09:58.440 --> 00:10:01.720 they actually overcome their nat electromagnetic repulsion. 213 00:10:01.759 --> 00:10:03.639 They stop pushing each other away, right. 214 00:10:03.480 --> 00:10:06.480 They slam together, and they fuse into helium. This is 215 00:10:06.559 --> 00:10:11.039 nuclear fusion, and it releases a staggering amount of energy. 216 00:10:10.919 --> 00:10:13.320 Like billions of nuclear bombs going off. 217 00:10:13.200 --> 00:10:16.840 Constantly, pretty much, and the outward pressure from that continuous 218 00:10:16.879 --> 00:10:21.679 nuclear explosion perfectly balances the inward crush of gravity. When 219 00:10:21.720 --> 00:10:25.000 that balance is achieved, a true star ignites. 220 00:10:25.440 --> 00:10:28.320 But a brown dwarf just doesn't have the gravitational muscle 221 00:10:28.360 --> 00:10:30.159 to reach that ignition point precisely. 222 00:10:30.320 --> 00:10:33.360 That is the issue. A brown dwarf gathers a substantial 223 00:10:33.399 --> 00:10:36.440 amount of mass, far more than a gas giant like Jupiter, 224 00:10:36.840 --> 00:10:39.600 but it falls agonizingly short of the mass required to 225 00:10:39.600 --> 00:10:41.320 trigger sustain hydrogen fusion. 226 00:10:41.440 --> 00:10:43.879 So it gets super hot, but it never quite catches fire. 227 00:10:44.039 --> 00:10:47.360 Right. The core gets incredibly hot, and it might briefly 228 00:10:47.440 --> 00:10:51.120 fuse some deterium, which is like a heavier isotope of hydrogen, 229 00:10:51.159 --> 00:10:52.960 but it can't maintain the main event. 230 00:10:53.240 --> 00:10:55.879 So if it doesn't have that outward nuclear explosion, why 231 00:10:55.879 --> 00:10:59.080 doesn't gravity just crush it into a black hole or something. 232 00:10:59.159 --> 00:11:03.080 What stops the c is actually this bizarre quantum mechanical 233 00:11:03.120 --> 00:11:06.000 phenomenon called electron degeneracy pressure. 234 00:11:06.120 --> 00:11:09.240 Electron degeneracy pressure that sounds intense. 235 00:11:09.120 --> 00:11:12.919 It is basically, the electrons in the core physically refuse 236 00:11:13.039 --> 00:11:15.720 to be squeezed any tighter. It's a fundamental rule of 237 00:11:15.799 --> 00:11:16.759 quantum physics. 238 00:11:16.879 --> 00:11:19.440 So it's just trapped in this weird middle ground. 239 00:11:19.600 --> 00:11:22.679 Exactly. It's too massive to be a regular planet, but 240 00:11:22.759 --> 00:11:26.039 it completely lacks the nuclear engine to be a true star. 241 00:11:26.159 --> 00:11:29.080 It just sits there, glowing faintly from the residual heat 242 00:11:29.080 --> 00:11:32.320 of its own gravitational collapse, like a dying ember. Yes, 243 00:11:32.679 --> 00:11:36.720 just slowly cooling off over billions of years. 244 00:11:37.120 --> 00:11:40.679 And because they lack that internal engine pushing outward. Brown 245 00:11:40.759 --> 00:11:43.799 dwarfs and even the smallest M type red dwarfs are 246 00:11:43.840 --> 00:11:45.559 physically tiny compared to our Sun. 247 00:11:45.679 --> 00:11:48.840 Right, Oh, incredibly tiny. An ultra cool dwarf is roughly 248 00:11:48.879 --> 00:11:50.399 ten percent of the Sun's diameter. 249 00:11:50.480 --> 00:11:52.799 Ten percent, So in terms of actual physical volume, how 250 00:11:52.799 --> 00:11:53.360 big is that? 251 00:11:53.480 --> 00:11:55.399 They are barely larger than Jupiter? 252 00:11:55.679 --> 00:11:58.720 Wow? Okay, So that brings the desk lamp analogy into 253 00:11:59.240 --> 00:12:04.080 sharp mathematics. Because the surface area of a star is 254 00:12:04.120 --> 00:12:07.039 proportional to the square of its radius, right right, So 255 00:12:07.039 --> 00:12:09.159 if you shrink the star's diameter to ten percent of 256 00:12:09.159 --> 00:12:12.799 the suns, its surface area actually shrinks to just one percent. 257 00:12:12.559 --> 00:12:15.480 Of the signs exactly. You put an Earth sized planet 258 00:12:15.559 --> 00:12:18.320 in front of that tiny surface area, and suddenly it's 259 00:12:18.360 --> 00:12:21.840 casting a massive shadow relative to the star's total output. 260 00:12:22.200 --> 00:12:26.120 You've completely rewritten the geometry of the transit. You've skewed 261 00:12:26.159 --> 00:12:28.840 it to favor finding small, rocky worlds. 262 00:12:29.240 --> 00:12:33.279 It's an elegant hack of astrophysical geometry. Honestly, you maximize 263 00:12:33.320 --> 00:12:37.080 the planet to star size ratio by creating that drastically 264 00:12:37.120 --> 00:12:40.480 higher contrast. You can use a relatively small, cost effective 265 00:12:40.519 --> 00:12:43.000 instrument in space to detect signals. 266 00:12:43.200 --> 00:12:45.960 It signals that normally you'd need what a massive, billion 267 00:12:46.000 --> 00:12:47.320 dollar telescope. 268 00:12:46.840 --> 00:12:49.519 To see exactly. It lets you do incredible science on 269 00:12:49.559 --> 00:12:50.000 a budget. 270 00:12:50.120 --> 00:12:53.000 Cost effective is definitely the operative phrase there, because the 271 00:12:53.000 --> 00:12:55.639 PA team isn't starting from scratch on this hardware. 272 00:12:55.720 --> 00:12:57.720 No, they have a huge head start, right. 273 00:12:58.200 --> 00:13:02.200 They are building on the legacy of these previous Canadian microsatellites, 274 00:13:02.600 --> 00:13:06.200 specifically one called MOST which launched back in two thousand 275 00:13:06.200 --> 00:13:09.279 and three and Neosat, which launched in twenty thirteen. 276 00:13:09.480 --> 00:13:12.399 Right, And when people hear the word satellite, they usually picture, 277 00:13:12.720 --> 00:13:14.879 you know, a school bus covered in gold foil. 278 00:13:15.000 --> 00:13:16.399 Yeah, something massive floating around. 279 00:13:16.480 --> 00:13:21.399 But microsatellites are a different breed entirely. They're essentially the 280 00:13:21.399 --> 00:13:25.000 size of a suitcase or maybe a small washing machine. 281 00:13:24.600 --> 00:13:26.399 A washing machine in space. 282 00:13:26.240 --> 00:13:30.080 Basically, but the science they yield is entirely disproportionate to 283 00:13:30.120 --> 00:13:33.840 their physical footprint. Take MOST for example, it stood for 284 00:13:33.960 --> 00:13:36.960 Microvariability and Oscillations of Stars. 285 00:13:36.840 --> 00:13:40.480 Which sounds very complicated. What was it actually trying to do? 286 00:13:40.639 --> 00:13:44.120 Initially it was designed for astro seismology. Okay, so studying 287 00:13:44.159 --> 00:13:48.480 starquakes exactly, studying the acoustic waves bouncing around inside stars 288 00:13:48.519 --> 00:13:50.919 to determine their age and what they're made of. But 289 00:13:51.000 --> 00:13:53.919 it proved to be so incredibly precise that the team 290 00:13:54.080 --> 00:13:57.639 actually pivoted it to exoplanet research and. 291 00:13:57.600 --> 00:13:59.279 It ended up making a huge discovery. 292 00:13:59.480 --> 00:14:03.240 Oh, one of the most foundational discoveries in early exoplanet 293 00:14:03.279 --> 00:14:04.679 atmospheric science. O. 294 00:14:04.720 --> 00:14:07.200 Yeah, I want to get into this because this discovery 295 00:14:07.320 --> 00:14:11.480 involved a hot Jupiter exoplanet orbiting a star called HD 296 00:14:11.799 --> 00:14:15.000 twenty zero nine four five eight kitchen name super catchy. 297 00:14:15.279 --> 00:14:19.240 So most observe this system and discover that this massive, 298 00:14:19.440 --> 00:14:22.879 blistering planet had a remarkably low albedo. 299 00:14:23.159 --> 00:14:23.440 Right. 300 00:14:23.519 --> 00:14:26.159 And albedo is just the measure of reflectivity, So like 301 00:14:26.639 --> 00:14:29.440 Earth has an albedo of about zero point three, meaning 302 00:14:29.480 --> 00:14:31.919 it reflects thirty percent of the sunlight that hits it. 303 00:14:31.840 --> 00:14:33.799 Mostly because of our clouds and ice caps. 304 00:14:33.919 --> 00:14:36.679 Right. But what most found was that this hot Jupiter 305 00:14:36.799 --> 00:14:38.480 was absorbing almost everything. 306 00:14:38.600 --> 00:14:41.120 It was darker than fresh asphalt. It had an albedo 307 00:14:41.200 --> 00:14:42.600 nearing absolute zero. 308 00:14:42.879 --> 00:14:45.679 This is so weird to think about a giant, pitch. 309 00:14:45.399 --> 00:14:49.320 Black planet, right because prior to that observation, there was 310 00:14:49.360 --> 00:14:53.000 this working assumption that hot jupiters might have highly reflective 311 00:14:53.120 --> 00:14:56.120 bright cloud decks, you know, maybe made of silicates or 312 00:14:56.240 --> 00:14:58.559 these exotic chemical compounds. 313 00:14:57.960 --> 00:14:59.879 Like Venus, but way bigger and hot. 314 00:15:00.240 --> 00:15:03.360 Exactly, Venus is super bright. But most proved that the 315 00:15:03.399 --> 00:15:06.679 atmosphere of this specific hot Jupiter was absorbing the star's 316 00:15:06.759 --> 00:15:07.399 energy directly. 317 00:15:07.480 --> 00:15:10.360 So what does a pitch black atmosphere actually look like? Chemically? 318 00:15:10.600 --> 00:15:15.799 It suggested a clear, totally cloudless upper atmosphere where alkali 319 00:15:15.879 --> 00:15:18.720 metals things like sodium and potassium were just absorbing all 320 00:15:18.759 --> 00:15:22.679 the visible light. Or perhaps it had incredibly dark light 321 00:15:22.759 --> 00:15:25.039 absorbing particulate hazes. 322 00:15:24.919 --> 00:15:26.840 So it's basically covered in cosmic. 323 00:15:26.440 --> 00:15:31.039 Smog pretty much. And that single finding forced atmospheric modelers 324 00:15:31.080 --> 00:15:34.840 to completely rethink how energy is deposited and circulated in 325 00:15:34.919 --> 00:15:35.840 these extreme. 326 00:15:35.600 --> 00:15:39.120 Environments, all from a suitcase sized satellite exactly. Then you 327 00:15:39.159 --> 00:15:42.519 had neosat follow up a decade later, tracking near Earth 328 00:15:42.600 --> 00:15:46.120 asteroids in space Debray, and both of these missions achieved 329 00:15:46.159 --> 00:15:50.000 world class science using telescopes that were only fifteen centimeters 330 00:15:50.000 --> 00:15:50.919 in diameter. 331 00:15:50.600 --> 00:15:51.279 Which is tiny. 332 00:15:51.399 --> 00:15:53.799 It's literally a six inch mirror. You can buy larger 333 00:15:53.840 --> 00:15:55.039 telescopes at a hobby shop. 334 00:15:55.159 --> 00:15:55.840 You really can. 335 00:15:56.039 --> 00:15:58.360 So now Pubitty is bumping that up to a twenty 336 00:15:58.399 --> 00:16:01.519 centimeter telescope, which is, you know, slightly bigger. But the 337 00:16:01.519 --> 00:16:03.679 real leap isn't just the size of the mirror. 338 00:16:03.440 --> 00:16:06.039 Is it, No, not at all. The real upgrade is 339 00:16:06.080 --> 00:16:09.240 the wavelengths of light it's engineer to actually see. 340 00:16:09.039 --> 00:16:11.759 Right, because most in neosat worked invisible. 341 00:16:11.360 --> 00:16:12.440 Light like our eyes do. 342 00:16:12.879 --> 00:16:17.840 But POET is expanding into the near ultraviolet, visible, near infrared, 343 00:16:18.120 --> 00:16:19.600 and short wavelength infrared. 344 00:16:19.919 --> 00:16:23.360 And that shift into the infrared is absolutely non negotiable 345 00:16:23.399 --> 00:16:24.840 given the targets they're going after. 346 00:16:24.759 --> 00:16:26.679 Because they're looking at those ultra cool dwarfs. 347 00:16:26.840 --> 00:16:29.720 Right, If you look at an ultracool dwarf invisible light, 348 00:16:29.960 --> 00:16:34.200 you're essentially looking at a blank wall. They emit incredibly 349 00:16:34.240 --> 00:16:35.559 little visible radiation. 350 00:16:35.960 --> 00:16:37.720 Why is that? Why are they so dim visually? 351 00:16:37.960 --> 00:16:42.120 It comes down to Ween's displacement law. It's a fundamental 352 00:16:42.159 --> 00:16:46.600 principle of thermal radiation. Basically, it states that the wavelength 353 00:16:46.679 --> 00:16:50.240 at which an object emits the most light is inversely 354 00:16:50.279 --> 00:16:51.720 proportional to its temperature. 355 00:16:51.759 --> 00:16:52.759 Okay, let's break that down. 356 00:16:52.919 --> 00:16:56.399 Sure, so our sun burns at roughly fifty five hundred 357 00:16:56.399 --> 00:17:00.799 degrees celsius, right, because of that specific temperature. Its peak 358 00:17:00.840 --> 00:17:03.960 emission is right in the middle of the visible spectrum 359 00:17:04.200 --> 00:17:05.680 yellow green light, which. 360 00:17:05.440 --> 00:17:07.240 Is why our eyes of all to see that specific 361 00:17:07.319 --> 00:17:08.079 light exactly. 362 00:17:08.400 --> 00:17:12.039 But brown dwarfs and red dwarfs are vastly cooler. Their 363 00:17:12.079 --> 00:17:15.000 surface temperatures might only be two thousand or maybe three 364 00:17:15.000 --> 00:17:16.039 thousand degrees, so. 365 00:17:16.000 --> 00:17:17.720 They aren't burning nearly as hot. 366 00:17:17.920 --> 00:17:21.440 Because they are cooler, the peak of their emission spectrum 367 00:17:21.480 --> 00:17:24.640 shifts heavily to the right. It moves entirely out of 368 00:17:24.640 --> 00:17:26.720 the visible spectrum and deep into the infrared. 369 00:17:26.799 --> 00:17:27.480 Oh I see. 370 00:17:27.640 --> 00:17:31.200 So if you want to study these stars, and more importantly, 371 00:17:31.519 --> 00:17:34.000 if you want to capture enough photons from them to 372 00:17:34.160 --> 00:17:37.079 measure a one percent dip when a planet transits, you 373 00:17:37.160 --> 00:17:39.680 have to tune your instrument to the frequency they are 374 00:17:39.720 --> 00:17:41.119 actually broadcasting on. 375 00:17:41.319 --> 00:17:42.720 You have to speak your language right. 376 00:17:42.880 --> 00:17:46.680 You need sensors capable of detecting heat radiation. 377 00:17:46.480 --> 00:17:50.720 Basically, but doing that requires a highly specialized detector. You 378 00:17:50.759 --> 00:17:54.359 can't just put a standard CCD chip from a digital 379 00:17:54.400 --> 00:17:57.799 point and shoot camera into space and hope to see infrared. 380 00:17:57.559 --> 00:17:59.839 No the thermal noise which is blind the sensor. 381 00:18:00.240 --> 00:18:02.880 And this brings up a really crucial question for me. 382 00:18:03.640 --> 00:18:07.440 A twenty cent meter telescope is still incredibly small, very small. 383 00:18:07.599 --> 00:18:10.079 We have ten meter telescope sitting on mountains right here 384 00:18:10.119 --> 00:18:14.359 on Earth, massive observatories. Why bother sending an eight inch 385 00:18:14.440 --> 00:18:17.119 mirror into orbit when we could just use a giant 386 00:18:17.200 --> 00:18:20.720 ground based observatory to look for these infrared transits? 387 00:18:21.000 --> 00:18:25.720 Because the Earth's atmosphere is an absolute nightmare for infrared astronomy. 388 00:18:25.799 --> 00:18:26.519 A nightmare. 389 00:18:26.599 --> 00:18:30.240 How well, First you have the turbulence of the atmosphere itself, 390 00:18:30.680 --> 00:18:33.599 which causes the light from the star to waver. 391 00:18:33.519 --> 00:18:35.559 And twinkle right the twinkling stars. 392 00:18:35.680 --> 00:18:39.640 That twinkling introduces an unacceptable level of noise into the 393 00:18:39.680 --> 00:18:44.400 photometric data. It ruins the precision. But the really insurmountable 394 00:18:44.480 --> 00:18:45.680 barrier is. 395 00:18:46.079 --> 00:18:48.720 Water vapor, water vapor like clouds. 396 00:18:48.519 --> 00:18:51.519 Even just the invisible moisture in the air. The water 397 00:18:51.640 --> 00:18:54.720 molecules in Earth's atmosphere act like a solid brick wall 398 00:18:54.799 --> 00:18:58.079 for many bands of infrared light. They physically absorb the 399 00:18:58.119 --> 00:19:01.200 incoming infrared radiation for it ever reaches the ground. 400 00:19:01.599 --> 00:19:04.839 Wow, So our atmosphere is effectively opaque to the very 401 00:19:04.920 --> 00:19:06.799