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 00:00:26.879 --> 00:00:29.000 I want you to start by picturing something in your 8 00:00:29.079 --> 00:00:31.679 mind right now. Just close your eyes for a second. 9 00:00:31.480 --> 00:00:33.399 If you can, well, unless you're drying, right. 10 00:00:33.320 --> 00:00:35.679 Oh yeah, Please do not close your eyes if you're driving, 11 00:00:35.960 --> 00:00:39.679 but otherwise, I want you to visualize holding an object 12 00:00:39.759 --> 00:00:41.759 the exact size of the planet Jupiter. 13 00:00:42.000 --> 00:00:44.000 That is a massive object to hold in your hand. 14 00:00:44.159 --> 00:00:48.280 Right. Just picture this massive swirling sphere resting right there 15 00:00:48.320 --> 00:00:51.679 in your palm, and you're bracing your arm, you know, 16 00:00:51.799 --> 00:00:57.399 preparing for the crushing incomprehensible weight of a gas. 17 00:00:57.039 --> 00:00:58.600 Giant, which would be terrifying. 18 00:00:58.759 --> 00:01:03.920 Exactly your gravitational pressure of a world that size, I mean, 19 00:01:03.920 --> 00:01:06.760 it should be enough to collapse your entire skeleton instantly 20 00:01:06.840 --> 00:01:09.280 without a doubt. But instead, when you actually try to 21 00:01:09.319 --> 00:01:13.000 lift it, you discover that this entire Jupiter sized world 22 00:01:13.040 --> 00:01:16.200 weighs less than a giant ball of cotton candy. 23 00:01:16.159 --> 00:01:17.519 Which just doesn't make any sense. 24 00:01:17.760 --> 00:01:21.799 It totally defies all your expectations. Your brain, it almost 25 00:01:21.799 --> 00:01:24.560 cannot compute what your hands are feeling because the physical 26 00:01:24.640 --> 00:01:27.400 laws you rely on every single day are suddenly screaming 27 00:01:27.439 --> 00:01:29.120 that this object should not exist. 28 00:01:29.519 --> 00:01:33.159 It creates a complete cognitive short circuit. I mean, our 29 00:01:33.200 --> 00:01:37.200 brains evolved on a rocky terrestrial world, you know, yeah, Earth, right, 30 00:01:37.519 --> 00:01:42.920 and here we inherently associate massive volume with massive mass. 31 00:01:43.000 --> 00:01:45.040 You look at a huge boulder, you know what possesses 32 00:01:45.159 --> 00:01:48.200 significant density. You don't expect it to float away. 33 00:01:48.280 --> 00:01:49.840 You expect to break your toe if you kick it. 34 00:01:50.319 --> 00:01:52.920 Exactly, So, you look at a planet the size of Jupiter, 35 00:01:53.359 --> 00:01:57.400 and astrophysics dictates that it must possess tremendous gravity driven 36 00:01:57.439 --> 00:02:00.799 by a deeply compressed core and layers of ultra dense material. 37 00:02:00.879 --> 00:02:04.840 Because that's what Jukuer is, yes, exactly. Breaking that fundamental 38 00:02:04.840 --> 00:02:09.000 physical expectation forces us to confront just how limited our 39 00:02:09.039 --> 00:02:13.599 earth bound common sense intuition actually is when we apply 40 00:02:13.680 --> 00:02:15.479 it to the broader mechanics of the cosmos. 41 00:02:15.560 --> 00:02:18.120 Okay, let's unpack this because leaving our common sense at 42 00:02:18.120 --> 00:02:20.560 the door is the absolute core of our mission. 43 00:02:20.560 --> 00:02:20.879 Today. 44 00:02:21.120 --> 00:02:24.039 We are traveling a long way out right, very long, yeah, 45 00:02:24.080 --> 00:02:26.599 eleven hundred and ten light years away from our Solar system. 46 00:02:26.759 --> 00:02:29.639 We are heading deep into the southern constellation of Volons, 47 00:02:29.759 --> 00:02:33.400 which is the flying Fish constellation, the great name, by 48 00:02:33.400 --> 00:02:36.039 the way, it really is. And we are focusing our 49 00:02:36.080 --> 00:02:40.319 attention on a newly confirmed pair of planets orbiting a 50 00:02:40.319 --> 00:02:45.479 sunlike G type main sequence star known as TOI seven 51 00:02:45.599 --> 00:02:46.039 nine to one. 52 00:02:46.599 --> 00:02:50.560 And we should clarify these aren't your standard exoplanets. 53 00:02:50.039 --> 00:02:52.599 No, not at all. They belong to a highly elusive 54 00:02:52.639 --> 00:02:54.159 category known as superpuffs. 55 00:02:54.479 --> 00:02:57.919 Superpuffs, which is such a whimsical label for a phenomenon 56 00:02:57.919 --> 00:03:01.159 that fundamentally challenges our model of planetary formation. 57 00:03:01.360 --> 00:03:03.039 It sounds like a serial brand, it does. 58 00:03:03.560 --> 00:03:07.719 But exploring these superpuffs requires us to well completely abandon 59 00:03:07.759 --> 00:03:11.240 the idea that our own Solar system is the standard 60 00:03:11.240 --> 00:03:12.360 blueprint for the universe. 61 00:03:12.400 --> 00:03:14.159 We're not the main character exactly. 62 00:03:14.560 --> 00:03:18.039 The Cosmos constantly proves that it operates on extreme variables, 63 00:03:18.439 --> 00:03:21.319 and our goal today is to examine the specific astrophysical 64 00:03:21.319 --> 00:03:23.800 conditions that allow us star to forge a planet that 65 00:03:23.879 --> 00:03:24.919 is practically. 66 00:03:24.479 --> 00:03:26.840 Hollow, which is mind blowing, right, and. 67 00:03:26.840 --> 00:03:30.199 To understand how these bizarre, fluffy anomalies force us to 68 00:03:30.520 --> 00:03:33.080 basically rewrite the timeline of cosmic evolution. 69 00:03:33.439 --> 00:03:35.680 So before we can even touch on the timeline of 70 00:03:35.719 --> 00:03:38.199 how a cotton candy world forms, we really have to 71 00:03:38.240 --> 00:03:41.879 ground ourselves in the sheer scale of the environment and 72 00:03:41.919 --> 00:03:45.039 the staggering physical contradiction of their existence. 73 00:03:45.159 --> 00:03:46.159 We have to set the scene. 74 00:03:46.360 --> 00:03:49.800 Right, Let's look at the neighborhood TOI seven ninety one 75 00:03:49.879 --> 00:03:52.360 is a leveand one hundred and ten light years away. 76 00:03:52.919 --> 00:03:56.240 For anyone who follows astronomy, you know that distance places 77 00:03:56.240 --> 00:03:59.159 the system well beyond our immediate stellar neighborhood. 78 00:03:59.240 --> 00:04:01.919 But it's still than the orion arm of our milky Way. 79 00:04:02.039 --> 00:04:05.360 Yeah, and what makes that specific distance interesting is, well, 80 00:04:05.439 --> 00:04:07.599 let's do the math for a second. A single light 81 00:04:07.680 --> 00:04:10.840 year is nearly six trillion miles, right, or about nine 82 00:04:10.840 --> 00:04:14.000 point seven trillion kilometers take, So if you multiply eleven 83 00:04:14.080 --> 00:04:15.360 hun and ten by six. 84 00:04:15.199 --> 00:04:18.720 Trillion, you're looking at over six point six quadrillion miles away. 85 00:04:18.839 --> 00:04:21.959 Six point six quadrillion miles That is just a mind 86 00:04:22.000 --> 00:04:25.560 boggling number. The light we are receiving from the star today. 87 00:04:25.639 --> 00:04:28.680 It began its journey during the European Middle Ages. 88 00:04:28.439 --> 00:04:30.959 Which is incredible to think about. We're essentially looking at 89 00:04:30.959 --> 00:04:34.160 a system deeply embedded in the galactic disc, which means 90 00:04:34.160 --> 00:04:37.519 the star formed from a very specific molecular cloud with 91 00:04:37.600 --> 00:04:39.800 its own unique ratio of heavy. 92 00:04:39.480 --> 00:04:41.879 Elements, and that ratio matters a lot, right. 93 00:04:41.759 --> 00:04:46.000 Oh absolutely. The metallicity of that specific region in the 94 00:04:46.000 --> 00:04:49.519 orion arm is a crucial piece of the puzzle. It 95 00:04:49.600 --> 00:04:53.839 directly dictates the raw materials available when TOI seven nine 96 00:04:53.879 --> 00:04:54.800 to one ignited. 97 00:04:54.879 --> 00:04:58.199 So if a star system forms in a region depleted 98 00:04:58.279 --> 00:04:59.800 of heavy elements. 99 00:04:59.720 --> 00:05:02.199 Stra ms call low metallicity right. 100 00:05:02.240 --> 00:05:05.720 Low metallicity, the resulting planets are going to be starved 101 00:05:05.759 --> 00:05:09.399 of the rocky silicates and iron needed to build dense cores. 102 00:05:09.560 --> 00:05:11.199 You can't build a rocky planet if you don't have 103 00:05:11.199 --> 00:05:12.279 any row exactly. 104 00:05:12.360 --> 00:05:14.560 So we are observing a system that had to construct 105 00:05:14.639 --> 00:05:18.120 Jupiter sized worlds using a radically different material budget than 106 00:05:18.160 --> 00:05:19.079 our own Sun. 107 00:05:18.920 --> 00:05:23.040 Had, and that budget deficit leads us directly to the 108 00:05:23.120 --> 00:05:24.480 density anomaly. 109 00:05:24.040 --> 00:05:26.720 Which is the craziest part. We see the profile, the 110 00:05:26.839 --> 00:05:29.959 raw volumetric footprint of a gas giant, but the spale 111 00:05:30.120 --> 00:05:31.720 is a complete cosmic deception. 112 00:05:31.920 --> 00:05:33.680 It's all a trick of the light almost. 113 00:05:33.600 --> 00:05:35.800 To put a massive anchor on this. Our own Jupiter 114 00:05:35.879 --> 00:05:38.720 is up to thirty five times denser than these two super. 115 00:05:38.560 --> 00:05:39.879 Puff thirty five times. 116 00:05:40.120 --> 00:05:42.800 When we think about Jupiter, we are just thinking about 117 00:05:42.800 --> 00:05:45.720 a big cloud. We are talking about a world so 118 00:05:46.040 --> 00:05:50.160 massive that the pressure inside it alters the fundamental phase 119 00:05:50.160 --> 00:05:50.959 states of matter. 120 00:05:51.279 --> 00:05:55.360 Yes, deep beneath Jupiter's cloud tops, the pressure is millions 121 00:05:55.360 --> 00:05:59.240 of times greater than Earth's atmosphere. It's violent, very It 122 00:05:59.319 --> 00:06:02.360 forces hydro and gas to compress so violently that the 123 00:06:02.399 --> 00:06:04.240 electrons literally detached from their. 124 00:06:04.199 --> 00:06:08.160 Nuclei, turning the gas into a sloshing ocean of liquid 125 00:06:08.199 --> 00:06:11.639 metallic hydrogen, which is just insane it is. 126 00:06:11.800 --> 00:06:14.240 And that generates a magnetic field that acts like a 127 00:06:14.319 --> 00:06:18.079 lethal radiation shield. Basically, Jupiter is an armored tank. 128 00:06:17.920 --> 00:06:20.240 A heavily armored tank, and then you look at these 129 00:06:20.240 --> 00:06:23.160 two planets and volins, and they are practically ghosts. 130 00:06:23.720 --> 00:06:26.839 The contrast is staggering when you really drill down into 131 00:06:26.839 --> 00:06:30.720 the thermodynamics of density, because density isn't just about weight. 132 00:06:31.040 --> 00:06:33.040 Great tells you what's going on inside exactly. 133 00:06:33.399 --> 00:06:36.399 It is the ultimate indicator of a planet's internal engine. 134 00:06:36.959 --> 00:06:41.639 Jupiter's high density implies a massive active core generating immense 135 00:06:41.680 --> 00:06:44.000 internal heat compressing the layers above it. 136 00:06:44.480 --> 00:06:47.680 So when we observe the superpuffs in the TOI seven 137 00:06:47.759 --> 00:06:51.839 ninety one system, their extreme lack of density tells us what. 138 00:06:52.360 --> 00:06:55.360 It tells us that this internal compression engine is either 139 00:06:55.439 --> 00:06:58.199 completely missing or fundamentally broken. 140 00:06:58.399 --> 00:07:02.199 Which brings me to this brilliant tactile analogy from George Drandsfield. 141 00:07:02.560 --> 00:07:05.040 She's an astronomer at the University of Oxford who worked 142 00:07:05.040 --> 00:07:06.439 on the analysis of these worlds. 143 00:07:06.560 --> 00:07:08.360 Yes, her work on this is fascinating. 144 00:07:08.560 --> 00:07:12.079 She described their density as being comparable to a quote 145 00:07:12.480 --> 00:07:15.439 nice blob of shaving foam fresh from the can. 146 00:07:15.759 --> 00:07:19.399 The physics behind that analogy are actually surprisingly accurate. 147 00:07:19.480 --> 00:07:21.519 Really like literal shaving cream. 148 00:07:21.600 --> 00:07:24.240 Yeah, think about it. When you dispense shaving cream. The 149 00:07:24.240 --> 00:07:27.399 sudden drop in pressure allows the propellant gas trapped inside 150 00:07:27.439 --> 00:07:30.680 the gel to rapidly expand. It creates a matrix of 151 00:07:30.720 --> 00:07:31.720 microscopic bubbles. 152 00:07:31.839 --> 00:07:33.560 Right, it puffs up in your hand exactly. 153 00:07:33.600 --> 00:07:37.199 The volume increases exponentially, but the mass remains identical to 154 00:07:37.240 --> 00:07:39.079 the tiny squirt of gel you started with. 155 00:07:39.279 --> 00:07:42.040 You press the button, the gel expands into this massive 156 00:07:42.079 --> 00:07:45.800 puffy cloud in your hand. It has dimension, it blocks light, 157 00:07:46.079 --> 00:07:48.480 but you can blow on it and it scatters. 158 00:07:48.160 --> 00:07:50.079 Which is a perfect visual for these planets. 159 00:07:50.360 --> 00:07:53.240 But this is where the shaving foam analogy creates a 160 00:07:53.319 --> 00:07:56.279 massive physical paradox for me, and I need you to 161 00:07:56.319 --> 00:07:59.360 resolve this on to my best. If these planets possess 162 00:07:59.399 --> 00:08:03.199 a density equivalent to expanded foam, how does a structure 163 00:08:03.279 --> 00:08:06.720 the size of Jupiter even maintain its cohesion? I mean, 164 00:08:06.759 --> 00:08:09.079 a planet isn't sitting in a vacuum, right. 165 00:08:08.920 --> 00:08:11.720 Well, space is a vacuum. But the environment around a 166 00:08:11.759 --> 00:08:13.519 star is certainly not empty, right. 167 00:08:13.560 --> 00:08:16.160 It's constantly being blasted by the solar wind of its 168 00:08:16.199 --> 00:08:18.720 host star. So why doesn't a planet made of literal 169 00:08:18.800 --> 00:08:22.000 fluff just get shredded and blown out into the interstellar medium. 170 00:08:22.120 --> 00:08:25.000 What's fascinating here is that the survival of these planets 171 00:08:25.360 --> 00:08:30.360 hinges entirely on a delicate, almost precarious gravitational truce. 172 00:08:30.519 --> 00:08:31.120 A truce. 173 00:08:31.480 --> 00:08:34.120 Yes. The extreme lack of density points us toward a 174 00:08:34.279 --> 00:08:37.840 very specific chemical reality. These planets possess what we call 175 00:08:37.919 --> 00:08:39.799 hydrogen helium dominated envelopes. 176 00:08:39.840 --> 00:08:41.600 Okay, hydrogen and helium, right. 177 00:08:41.600 --> 00:08:44.639 They are the two lightest, most buoyant elements in the universe. 178 00:08:45.080 --> 00:08:48.840 But even though they are incredibly light, they still possess mass. 179 00:08:48.679 --> 00:08:51.039 And if they have mass, they have gravity. But the 180 00:08:51.080 --> 00:08:54.320 gravity of a shaving foam planet must be incredibly weak. 181 00:08:54.480 --> 00:08:55.279 It is very weak. 182 00:08:55.399 --> 00:08:57.279 So how is it strong enough to hold on to 183 00:08:57.399 --> 00:09:01.120 gases that inherently want to expand and dissipate, especially when 184 00:09:01.159 --> 00:09:02.480 heated by a nearby star. 185 00:09:02.720 --> 00:09:05.639 The mechanism keeping them intact is a concept known as 186 00:09:05.679 --> 00:09:07.639 the genes escape parameter. 187 00:09:07.320 --> 00:09:08.519 Deems a stape. 188 00:09:08.799 --> 00:09:12.639 Every gas molecule in a planet's atmosphere possesses kinetic energy, 189 00:09:12.879 --> 00:09:16.720 meaning it is constantly vibrating and bouncing around. The hotter 190 00:09:16.799 --> 00:09:18.919 the gas, the faster the molecules move. 191 00:09:19.000 --> 00:09:19.600 That makes sense. 192 00:09:19.720 --> 00:09:22.480 Heat is energy, right, and if a molecule reaches a 193 00:09:22.480 --> 00:09:26.320 specific speed, the escape velocity, it overcomes the planet's gravitational 194 00:09:26.360 --> 00:09:28.320 pull and bleeds off into space. 195 00:09:28.559 --> 00:09:32.320 So it's a race basically between the planet's gravitational anchor 196 00:09:32.399 --> 00:09:35.000 and the thermal energy injected by the star trying to 197 00:09:35.039 --> 00:09:36.279 boil the atmosphere away. 198 00:09:36.360 --> 00:09:39.399 Precisely that because TOI seven nine to one is a 199 00:09:39.440 --> 00:09:42.639 sun like star. It is blasting these planets with high 200 00:09:42.759 --> 00:09:46.879 energy ultraviolet radiation, just baking them. Yeah. This radiation strikes 201 00:09:46.919 --> 00:09:50.000 the outer layers of the hydrogen helium envelope, heating the 202 00:09:50.000 --> 00:09:52.960 gas and driving up its kinetic energy. Now, the planet's 203 00:09:53.000 --> 00:09:56.200 gravity is incredibly weak due to its low mass, so 204 00:09:56.240 --> 00:09:57.960 the escape velocity is quite low. 205 00:09:58.039 --> 00:09:59.399 So why hasn't it all evaperated? 206 00:09:59.480 --> 00:10:01.759 The reason the the entire planet hasn't vanished is that 207 00:10:01.799 --> 00:10:05.759 the outer envelope absorbs the brunt of this thermal assault, 208 00:10:06.080 --> 00:10:09.759 swelling outward traumatically rather than instantly boiling off. 209 00:10:09.840 --> 00:10:13.200 Oh wow, So it inflates like a cosmic hot air 210 00:10:13.240 --> 00:10:15.240 balloon to absorb the energy. 211 00:10:15.080 --> 00:10:19.039 Exactly expanding its volume to dissipate the heat, which in 212 00:10:19.080 --> 00:10:22.200 turn drastically lowers its overall density even further. 213 00:10:22.519 --> 00:10:26.440 That thermodynamic expansion is exactly why they appear as superpuffs. 214 00:10:26.799 --> 00:10:30.600 The planet isn't just naturally fluffy. It is actively ballooning 215 00:10:30.679 --> 00:10:32.440 in response to stellar radiation. 216 00:10:32.799 --> 00:10:36.000 It's a reaction to the environment. The gravitational pull from 217 00:10:36.039 --> 00:10:38.960 the core is just barely sufficient to tether the lower 218 00:10:39.039 --> 00:10:42.480 layers of the envelope, creating this fragile equilibrium. 219 00:10:42.519 --> 00:10:43.480 It sounds stressful. 220 00:10:43.519 --> 00:10:46.399 He is a constant agonizing tug of war between the 221 00:10:46.440 --> 00:10:49.000 star trying to strip the planet naked and the planet's 222 00:10:49.000 --> 00:10:51.519 weak gravity clinging to its expanding outer shell. 223 00:10:51.799 --> 00:10:55.480 That fragile equilibrium creates such a vivid, almost haunting image 224 00:10:55.480 --> 00:10:57.639 of these worlds. But I think we need to bust 225 00:10:57.679 --> 00:10:59.080 a pervasive myth right now. 226 00:10:59.120 --> 00:11:01.399 For everyone listening, I know exactly where you're going with this. 227 00:11:01.759 --> 00:11:04.960 Because we use terms like cotton candy, it's incredibly easy 228 00:11:05.000 --> 00:11:09.279 to visualize these super puffs as giant, glowing pink carnival 229 00:11:09.320 --> 00:11:11.759 treats floating in the void, which. 230 00:11:11.600 --> 00:11:14.240 Would look cool but is entirely wrong. 231 00:11:14.480 --> 00:11:18.000 Right If a probe we're actually flying past these planets, 232 00:11:18.039 --> 00:11:22.080 the visual reality dictated by atmospheric physics would be entirely different. 233 00:11:22.120 --> 00:11:23.919 They are not pink, not at all. 234 00:11:24.240 --> 00:11:27.879 The optical properties of a hydrogen rich envelope completely rule 235 00:11:27.919 --> 00:11:31.759 out any neon pink aesthetics. The visual appearance of a 236 00:11:31.799 --> 00:11:35.919 gas giant is dictated entirely by how its atmosphere interacts 237 00:11:35.919 --> 00:11:37.039 with incoming. 238 00:11:36.600 --> 00:11:39.960 Starlight, and that's based on the chemicals in the air, exactly. 239 00:11:39.480 --> 00:11:43.039 A process largely governed by Raleigh scattering and the presence 240 00:11:43.039 --> 00:11:44.799 of specific cloud condensates. 241 00:11:44.879 --> 00:11:47.279 Okay, let's break that down. So if we have a deep, 242 00:11:47.519 --> 00:11:51.799 relatively clear atmosphere dominated by hydrogen and helium, we're likely 243 00:11:51.840 --> 00:11:54.519 looking at a world that scatters short wavelength. 244 00:11:54.200 --> 00:11:55.919 Light, which is the blue end of the spectrum. 245 00:11:56.000 --> 00:11:58.919 Right, That would give it a deep, translucent blue hue 246 00:11:59.039 --> 00:12:02.279 functioning on the exit act same basic optical principles that 247 00:12:02.320 --> 00:12:03.600 make our own sky blue on. 248 00:12:03.559 --> 00:12:06.559 Earth, though likely much more profound given the sheer depth 249 00:12:06.559 --> 00:12:10.759 of the envelope. A pure hydrogen atmosphere would indeed scatter 250 00:12:10.919 --> 00:12:13.320 blue light very efficiently. 251 00:12:13.039 --> 00:12:15.480 But it might not be pure hydrogen right. 252 00:12:15.799 --> 00:12:19.039 Transfield's research team suspects that these envelopes might not be 253 00:12:19.080 --> 00:12:23.440 clear at all. The thermodynamic profile of these superpuffs suggests 254 00:12:23.440 --> 00:12:26.360 that their upper atmospheres are likely cool enough to support 255 00:12:27.000 --> 00:12:29.039 massive global cloud decks. 256 00:12:29.559 --> 00:12:32.320 But obviously these wouldn't be water clouds like we have 257 00:12:32.399 --> 00:12:34.120 on Earth right, No, or. 258 00:12:34.080 --> 00:12:36.039 Even the ammonia clouds that ban Jupiter. 259 00:12:36.320 --> 00:12:38.480 So what kind of chemistry are we talking about for 260 00:12:38.679 --> 00:12:40.519 clouds on a shaving foam planet. 261 00:12:40.720 --> 00:12:43.639 Depending on the specific temperature, we could be looking at 262 00:12:43.679 --> 00:12:47.960 clouds composed of photochemical hazes like smog kinda yeah, or 263 00:12:48.000 --> 00:12:52.039 even exotic condensates like salt crystals or silicate dust suspended 264 00:12:52.080 --> 00:12:53.120 high in the atmosphere. 265 00:12:53.159 --> 00:12:55.519 Wait, really salt clouds, yeah. 266 00:12:55.320 --> 00:12:58.039 Salt, or even tiny grains of sand. Essentially yeah. And 267 00:12:58.080 --> 00:13:00.919 if the atmosphere is choked with these high altitude hazes, 268 00:13:01.200 --> 00:13:04.600 the optical effect shifts from Raleigh scattering to me scattering. 269 00:13:04.919 --> 00:13:08.240 Okay, me scattering. That's where the particles are large enough 270 00:13:08.240 --> 00:13:11.240 to scatter all wavelengths of visible light equally right. 271 00:13:11.120 --> 00:13:14.559 Exactly, so instead of just scattering blue, it scatters everything. 272 00:13:14.679 --> 00:13:18.000 Which means, rather than a translucent blue sphere, we might 273 00:13:18.039 --> 00:13:21.639 be looking at a brilliant, blindingly white world. Just a 274 00:13:21.720 --> 00:13:25.360 stark white orb like an impossibly massive snowball suspended in 275 00:13:25.399 --> 00:13:29.480 the darkness, but with edges that are incredibly soft and diffuse, 276 00:13:29.879 --> 00:13:32.440 fading seamlessly into the vacuum of space. 277 00:13:32.759 --> 00:13:35.200 The lack of a sharp limb, the distinct edge we 278 00:13:35.240 --> 00:13:38.039 normally see when we look at a planet, is a defining. 279 00:13:37.720 --> 00:13:40.240 Characteristic here because it's so puffy, right. 280 00:13:40.519 --> 00:13:43.480 The atmosphere is so extended and so diffuse that there 281 00:13:43.519 --> 00:13:46.799 is no hard boundary, just a gradual, hazy transition from 282 00:13:46.840 --> 00:13:49.840 the intense white reflection of the cloud tops out into 283 00:13:49.840 --> 00:13:51.720 the blackness of the Volan's constellation. 284 00:13:52.159 --> 00:13:55.919 Visualizing a hazy edgeless white giant is beautiful. But what 285 00:13:56.120 --> 00:13:58.960 absolutely staggers me is the technological gauntlet we had to 286 00:13:59.039 --> 00:14:02.240 run just to prove these soft edged ghosts exist. 287 00:14:02.559 --> 00:14:03.320 It wasn't easy. 288 00:14:03.600 --> 00:14:06.480 Finding a superpuff isn't a matter of just pointing a 289 00:14:06.519 --> 00:14:10.519 telescope and taking a picture. It requires a relentless, multi 290 00:14:10.600 --> 00:14:13.799 stage photometric and spectroscopic relay race. 291 00:14:14.240 --> 00:14:16.360 Or relay race is the perfect way to describe it. 292 00:14:16.480 --> 00:14:18.919 Let's break down the timeline, starting with the transit detection 293 00:14:19.080 --> 00:14:21.440 by NASA's test satellite Test. 294 00:14:21.279 --> 00:14:25.360 The Transiting Exoplanet Survey satellite. It operates on a brilliantly 295 00:14:25.440 --> 00:14:29.320 simple geometric principle, but executed with terrifying precision. 296 00:14:29.559 --> 00:14:31.519 It's just watching for shadows basically. 297 00:14:31.679 --> 00:14:35.039 Essentially, yes, it watches for transits, which occur when a 298 00:14:35.039 --> 00:14:38.639 planet's orbit carries it directly between its host star and 299 00:14:38.679 --> 00:14:39.519 our vantage. 300 00:14:39.200 --> 00:14:40.360 Point, like an eclipse. 301 00:14:40.559 --> 00:14:43.240 Exactly as the planet crosses the face of the star, 302 00:14:43.720 --> 00:14:46.000 it blocks a microscopic fraction of the star's light. 303 00:14:46.240 --> 00:14:49.000 But wait, because these planets have such a low density, 304 00:14:49.399 --> 00:14:53.200 they don't have a solid silhouette. Does that diffuse, hazy 305 00:14:53.360 --> 00:14:56.360 edge make the transit harder for tests to detect? 306 00:14:56.639 --> 00:14:58.000 That is a very good question. 307 00:14:58.279 --> 00:15:01.399 I mean, if the edges are base sickly transparent gas, 308 00:15:01.519 --> 00:15:04.840 does the stars light just bleed through, muddying the data. 309 00:15:05.159 --> 00:15:08.639 That is an excellent complication to highlight. The diffuse nature 310 00:15:08.639 --> 00:15:11.559 of the atmosphere absolutely does affect the light curve. 311 00:15:11.600 --> 00:15:14.320 The light curve is the graph of the star's brightness 312 00:15:14.320 --> 00:15:14.840 over time. 313 00:15:15.000 --> 00:15:18.000 Right. Instead of a sharp, sudden dip in starlight as 314 00:15:18.000 --> 00:15:21.720 a solid, rocky edge crosses the star, a superpuff can 315 00:15:21.759 --> 00:15:25.080 create a slightly softer, more gradual curve because a light 316 00:15:25.159 --> 00:15:28.919 is filtering through the haze exactly the tenuous outer atmosphere 317 00:15:28.960 --> 00:15:32.000 begins to filter the light before the opaque main body 318 00:15:32.039 --> 00:15:36.200 fully blocks it. However, the core photometric dip is still 319 00:15:36.240 --> 00:15:38.879 governed by the sheer cross sectional area of the planet, 320 00:15:38.960 --> 00:15:41.639 and tests can handle that oh easily. Yeah. Test is 321 00:15:41.639 --> 00:15:45.799 equipped with four wide field CCD cameras that are sensitive 322 00:15:45.879 --> 00:15:48.759 enough to measure changes in stellar brightness on the order 323 00:15:48.799 --> 00:15:49.759 of parts per million. 324 00:15:50.039 --> 00:15:51.600 That is absurdly precise. 325 00:15:51.759 --> 00:15:52.519 It really is so. 326 00:15:52.639 --> 00:15:55.240 Even with a soft edge, test measures the total drop 327 00:15:55.279 --> 00:15:58.519 in photons and calculates the physical diameter of the blockage. 328 00:15:59.000 --> 00:16:02.000 Test runs the number and says, we have an object 329 00:16:02.000 --> 00:16:04.840 here that has the exact volumetric radius of Jupiter. 330 00:16:05.039 --> 00:16:08.080 But knowing the size is only half the battle right. 331 00:16:07.960 --> 00:16:11.320 Because tess gives us the geometry, but it is completely 332 00:16:11.360 --> 00:16:12.720 blind to the mass. 333 00:16:12.399 --> 00:16:15.519 And geometry without mass leaves you entirely in the dark. 334 00:16:15.720 --> 00:16:16.639 Regarding density. 335 00:16:16.799 --> 00:16:19.159 You can't know how heavy something is just by looking 336 00:16:19.159 --> 00:16:19.879 at its shadow. 337 00:16:20.200 --> 00:16:24.639 Precisely. To weigh a planet eleven and ten light years away, 338 00:16:24.919 --> 00:16:27.679 we have to shift our methodology entirely. We have to 339 00:16:27.679 --> 00:16:30.919 look at the gravitational influence the planet exerts on its 340 00:16:30.960 --> 00:16:31.480 host star. 341 00:16:31.759 --> 00:16:34.559 And this is where the astronomical relay rays handed the 342 00:16:34.559 --> 00:16:37.960 baton down to ground based observatories. 343 00:16:37.279 --> 00:16:40.559 Specifically utilizing the ASTEP telescope. 344 00:16:40.000 --> 00:16:42.919 Down in Antarctica. And I have to ask why Antarctica. 345 00:16:43.000 --> 00:16:45.000 That seems like an incredibly hostile place to put a 346 00:16:45.000 --> 00:16:48.080 delicate astronomical instrument when you could just, I don't know, 347 00:16:48.120 --> 00:16:49.480 build it in Hawaii or Chile. 348 00:16:49.759 --> 00:16:53.519 It is hostile, but Antarctica offers a very specific observational 349 00:16:53.559 --> 00:16:56.600 advantage the polar night ah. 350 00:16:56.720 --> 00:16:58.639 Of course, the sun doesn't rise right. 351 00:16:58.919 --> 00:17:02.600 When you are trying to measure incredibly subtle gravitational interactions 352 00:17:02.639 --> 00:17:07.160 over long orbital periods, you need continuous, uninterrupted observation. 353 00:17:06.799 --> 00:17:08.720 Because if you miss a piece of the orbit, your 354 00:17:08.759 --> 00:17:09.519 math is wrong. 355 00:17:09.839 --> 00:17:14.160 Exactly. A telescope in Chili is blind for twelve hours 356 00:17:14.160 --> 00:17:16.640 a day when the sun is up, but a step 357 00:17:16.960 --> 00:17:20.440 positioned at the Concordius station on the Antarctic Plateau can 358 00:17:20.480 --> 00:17:23.680 stare at the Volan's constellation continuously for months at a 359 00:17:23.759 --> 00:17:25.680 time during the Antarctic winter. 360 00:17:25.559 --> 00:17:27.920 Without the diurnal cycle breaking the data stream. 361 00:17:28.039 --> 00:17:30.640 It just stares into the dark, gathering data. 362 00:17:30.319 --> 00:17:34.480 And that continuous data stream is hunting for radial velocity shifts. Right, 363 00:17:35.480 --> 00:17:37.599 walk us through the mechanics of how we use that 364 00:17:37.720 --> 00:17:40.519 to weigh a planet, because we know gravity is a 365 00:17:40.519 --> 00:17:43.759 two way street. It is the star pulls the planet 366 00:17:43.799 --> 00:17:47.480 into orbit, but the planet's mass also tugs back on 367 00:17:47.640 --> 00:17:50.720 the star, causing the star to wobble slightly around the 368 00:17:50.759 --> 00:17:52.240 system's center of mass. 369 00:17:52.359 --> 00:17:56.119 The radial velocity method measures that precise stellar wobble by 370 00:17:56.160 --> 00:17:58.920 analyzing the star's light through a spectrograph. 371 00:17:59.000 --> 00:18:01.720 So we're looking at the light again, but differently. 372 00:18:01.440 --> 00:18:04.559 Right as the unseen planet's gravity pulls the star slightly 373 00:18:04.640 --> 00:18:08.160 toward Earth. The light waves emitted by the star are compressed. 374 00:18:08.680 --> 00:18:12.440 This shifts them slightly toward the blue end of the electromagnetic. 375 00:18:11.640 --> 00:18:13.480 Spectrum, and then it swings around. 376 00:18:13.319 --> 00:18:15.519 As the planet orbits to the other side and pulls 377 00:18:15.559 --> 00:18:18.119 the star away from us. The light waves stretch out, 378 00:18:18.319 --> 00:18:19.559 shifting toward the red end. 379 00:18:19.680 --> 00:18:23.319 The Doppler effect exactly like the pitch of an ambulance siren, 380 00:18:23.400 --> 00:18:26.000 rising as it approaches you and falling as it speeds away, 381 00:18:26.519 --> 00:18:29.319 except here we are measuring the changing pitch of starlight. 382 00:18:29.519 --> 00:18:30.720 That's a perfect analogy. 383 00:18:31.079 --> 00:18:34.119 But wait. If these super puffs have the mass of 384 00:18:34.240 --> 00:18:37.160 just a few earths spread out over the massive volume 385 00:18:37.200 --> 00:18:41.160 of Jupiter, their gravitational tug must be microscopic. It is 386 00:18:41.200 --> 00:18:45.119 incredibly faint, because the star TOI seven ninety one is massive. 387 00:18:45.480 --> 00:18:48.000 Getting a shaving foam planet to make it wobble must 388 00:18:48.000 --> 00:18:51.359 be like ah a mosquito trying to drag a bowling ball. 389 00:18:51.440 --> 00:18:55.160 The signal to noise ratio is punishing, truly punishing. We 390 00:18:55.200 --> 00:18:57.920 are talking about detecting a star moving in a velocity 391 00:18:58.000 --> 00:19:00.720 of perhaps a few meters per second from a distance 392 00:19:00.759 --> 00:19:02.319 of over a thousand light years away. 393 00:19:02.559 --> 00:19:04.680 That's walking speed. We're detecting a star walking. 394 00:19:04.880 --> 00:19:08.799 Yes. Ground based spectrographs have to isolate that tiny rismic 395 00:19:08.839 --> 00:19:12.200 Doppler shift from the chaotic, turbulent boiling of the star's 396 00:19:12.240 --> 00:19:15.799 own surface plasma. It's an immense data challenge. 397 00:19:15.440 --> 00:19:16.119 But they did it. 398 00:19:16.200 --> 00:19:19.440 They did, and when the ASTEP data was finally analyzed, 399 00:19:19.799 --> 00:19:24.079 the math revealed the paradox. Tests provided a massive volume, 400 00:19:24.559 --> 00:19:27.279 a step provided an agonizingly tiny mass. 401 00:19:27.359 --> 00:19:30.240