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 --> 00:00:30.480 Hello it is It's really fantastic to have you back 8 00:00:30.519 --> 00:00:32.719 with us for this discussion. I was actually I was 9 00:00:32.759 --> 00:00:35.560 staring at my bookshelf this morning. Well, I say bookshelf, 10 00:00:35.560 --> 00:00:37.600 I've seen it's more of a right, it's a chaotic 11 00:00:37.600 --> 00:00:39.920 pile of paper and half read journals. But I was 12 00:00:39.960 --> 00:00:42.880 looking at this mess and just thinking about rules. As 13 00:00:42.880 --> 00:00:45.320 a species, we are just so obsessed with them. 14 00:00:45.320 --> 00:00:47.840 Oh. Absolutely, we crave patterns. 15 00:00:47.399 --> 00:00:49.600 We really do. We want to know that a leads 16 00:00:49.679 --> 00:00:51.880 to be and that the socks go on the top 17 00:00:52.000 --> 00:00:54.280 drawer and the heavy winter coats go in the closet. 18 00:00:54.359 --> 00:00:55.320 We need that order. 19 00:00:56.000 --> 00:00:58.759 Well, it's a survival mechanism, really, I mean, if our 20 00:00:58.799 --> 00:01:05.000 ancestors couldn't wreckgize the pattern of say, rustling grass usually equals. 21 00:01:04.599 --> 00:01:08.040 Predator right, run away exactly. 22 00:01:08.000 --> 00:01:10.599 We wouldn't be sitting here recording this analysis right now 23 00:01:10.599 --> 00:01:13.239 if they hadn't found order in the noise. We are 24 00:01:13.439 --> 00:01:14.920 completely hardwired for it. 25 00:01:15.280 --> 00:01:17.079 But the funny thing is we don't just apply that 26 00:01:17.159 --> 00:01:20.480 to the savannah or our closets. We project that exact 27 00:01:20.480 --> 00:01:23.280 same desire for order onto the cosmos itself. 28 00:01:23.359 --> 00:01:24.879 We want the universe to be tidy. 29 00:01:25.120 --> 00:01:27.519 Yes, For the longest time, we looked up at the 30 00:01:27.599 --> 00:01:32.799 night sky and just assumed there was this cosmic building code, 31 00:01:32.840 --> 00:01:36.239 like a set of architectural blueprints that every single star 32 00:01:36.280 --> 00:01:38.120 system had to follow and to be fair. 33 00:01:38.640 --> 00:01:41.920 For a while, looking at our own neighborhood, it seemed 34 00:01:41.920 --> 00:01:44.159 like a pretty rock solid argument because. 35 00:01:43.920 --> 00:01:46.040 The Solar system is surprisingly neat. 36 00:01:46.159 --> 00:01:48.920 It really is. It's easy to assume your own backyard 37 00:01:49.000 --> 00:01:51.439 is the standard for the entire neighborhood. And if you 38 00:01:51.480 --> 00:01:56.680 look at the solar system, it's astonishingly tidy. It's almost clockwork. 39 00:01:56.840 --> 00:02:00.239 You have a very specific layout. So let's actually dismantle 40 00:02:00.239 --> 00:02:03.159 that Solar system standard before we completely blow it up 41 00:02:03.239 --> 00:02:03.879 later in the show. 42 00:02:03.920 --> 00:02:04.719 Good idea. 43 00:02:04.879 --> 00:02:07.120 When you look at the Sun and it's eight planets 44 00:02:07.359 --> 00:02:09.639 and sorry, Pluto, we're still not counting you today. But 45 00:02:09.719 --> 00:02:12.240 you see two very distinct neighborhoods. 46 00:02:12.319 --> 00:02:14.879 Right, It's essentially a tail of two zones. In the 47 00:02:14.919 --> 00:02:17.560 inner zone huddle really close to the Sun, you have 48 00:02:17.599 --> 00:02:19.199 the terrestrial planets. 49 00:02:18.960 --> 00:02:22.639 Mercury, Venus, Earth, Mars exactly. 50 00:02:22.759 --> 00:02:26.639 These are the rocks. They're relatively small, they're dense, they're 51 00:02:26.759 --> 00:02:29.439 rich in iron and silicates. They're solid worlds. 52 00:02:29.560 --> 00:02:31.479 I always think of them as the heavy metal band 53 00:02:31.479 --> 00:02:32.599 of the Solar System. 54 00:02:32.840 --> 00:02:34.599 That's actually not a bad way to look at it. 55 00:02:35.039 --> 00:02:37.400 But then you cross a boundary. In astronomy, we call 56 00:02:37.439 --> 00:02:40.400 this the frost line or the snow line. 57 00:02:40.120 --> 00:02:42.280 And this is a super crucial concept for what we're 58 00:02:42.319 --> 00:02:43.159 talking about today. 59 00:02:43.199 --> 00:02:46.719 It is this line is the specific distance from the 60 00:02:46.759 --> 00:02:50.919 star where the temperature drops enough for volatile compounds to. 61 00:02:50.879 --> 00:02:54.319 Freeze things like water, ammonia, methane. 62 00:02:54.520 --> 00:02:58.479 Yes, they can dense into solid ice grains. Inside that line, 63 00:02:58.479 --> 00:03:02.840 it's too hot vapor. But outside that line, water is 64 00:03:03.360 --> 00:03:04.599 essentially a solid rock. 65 00:03:04.879 --> 00:03:07.599 Ice behaves like rock out there, exactly, And. 66 00:03:07.520 --> 00:03:10.120 That boundary marks the beginning of the outer zone. This 67 00:03:10.159 --> 00:03:12.840 is the realm of the gas giants and the ice giants. 68 00:03:12.960 --> 00:03:16.000 Jupiter, Saturn, Urinus, Neptune right. 69 00:03:16.240 --> 00:03:19.039 And his worlds are just massive. They dominate the outer 70 00:03:19.120 --> 00:03:23.159 system with thick, swirling atmospheres that are thousands of miles deep. 71 00:03:23.280 --> 00:03:25.759 So the cosmic building code that we wrote based on 72 00:03:25.800 --> 00:03:28.879 this observation was pretty simple. Rocks on the inside, gas 73 00:03:28.960 --> 00:03:29.960 giants on the outside. 74 00:03:29.960 --> 00:03:30.560 That was the rule. 75 00:03:30.800 --> 00:03:34.000 And this wasn't just an aesthetic choice by early astronomers, right, Oh, 76 00:03:34.039 --> 00:03:35.680 there is hard physics backing this up. 77 00:03:35.879 --> 00:03:38.439 Oh, there's very solid physics behind it. It all comes 78 00:03:38.439 --> 00:03:41.199 down to the behavior of the protoplanetary disk. 79 00:03:41.159 --> 00:03:45.080 The swirling saucer of gas and dust that surrounds a baby. 80 00:03:44.840 --> 00:03:48.360 Star right when a system is forming. The area close 81 00:03:48.400 --> 00:03:52.560 to the star is an absolute inferno. The intense radiation 82 00:03:52.759 --> 00:03:55.560 and the heat they prevent those really light gases like 83 00:03:55.680 --> 00:03:57.800 hydrogen and helium from sticking around. 84 00:03:57.960 --> 00:03:59.680 They just get blasted away. 85 00:03:59.639 --> 00:04:03.400 Exactlyactly, blown away by stellar winds. And more importantly, the 86 00:04:03.439 --> 00:04:05.560 seeds of the planets in that inner zone are made 87 00:04:05.599 --> 00:04:09.080 only of rock and metal, which are actually pretty rare 88 00:04:09.120 --> 00:04:10.879 materials in the grand scheme of the universe. 89 00:04:10.960 --> 00:04:13.719 So you have a scarcity of building materials close to 90 00:04:13.759 --> 00:04:14.400 the star. 91 00:04:14.319 --> 00:04:16.560 You do you can only build a small planet because 92 00:04:16.600 --> 00:04:18.680 there just isn't enough rock to build a big one, 93 00:04:19.160 --> 00:04:21.480 and because it's so hot, even if you did grab 94 00:04:21.519 --> 00:04:23.959 some gas, you can't hold onto a thick atmosphere. 95 00:04:24.000 --> 00:04:25.000 It just boils off. 96 00:04:25.079 --> 00:04:26.639 It gets stripped away. It's like trying to hold a 97 00:04:26.680 --> 00:04:29.120 snowball in a sauna. It's just not going to last. 98 00:04:29.240 --> 00:04:32.279 Whereas if we travel past the frost line. 99 00:04:31.920 --> 00:04:34.600 It is a totally different story out there. It's freezing. 100 00:04:35.439 --> 00:04:38.959 Ices are solid, so suddenly there is a massive abundance 101 00:04:38.959 --> 00:04:42.519 of building material because ice is incredibly common. 102 00:04:42.319 --> 00:04:43.839 So you can build a much bigger core. 103 00:04:44.120 --> 00:04:46.879 Exactly, you can build a solid core that is ten, 104 00:04:47.000 --> 00:04:50.279 maybe fifteen times the mass of Earth. And once a 105 00:04:50.319 --> 00:04:54.920 planetary core gets that heavy, it's gravity becomes so strong 106 00:04:55.000 --> 00:04:57.319 that it starts sucking up all the gas in the neighborhood. 107 00:04:57.439 --> 00:04:58.800 It's a tipping point, right, It. 108 00:04:58.759 --> 00:05:02.319 Becomes a runaway process, vacuums up the hydrogen and helium, 109 00:05:02.319 --> 00:05:03.680 and boom, you get a Jupiter. 110 00:05:03.800 --> 00:05:08.199 So the logic is completely sound. Heat creates rocks, cold 111 00:05:08.319 --> 00:05:11.959 creates giants. We had the observation, we had the physics, 112 00:05:12.319 --> 00:05:14.199 and we basically wrote the law, and. 113 00:05:14.240 --> 00:05:17.720 For decades pretty much all planetary formation models were built 114 00:05:17.839 --> 00:05:20.560 entirely around this architecture. We just assumed that if we 115 00:05:20.600 --> 00:05:22.759 looked at other stars we would see the exact same. 116 00:05:22.600 --> 00:05:25.879 Thing, which perfectly brings us to our topic today. Because 117 00:05:25.879 --> 00:05:28.720 of the universe, as it turns out, really enjoys mocking 118 00:05:29.000 --> 00:05:29.680 our laws. 119 00:05:29.839 --> 00:05:31.279 It does have a habit of doing that. 120 00:05:31.439 --> 00:05:33.480 Just when we thought we had the blueprint figured out, 121 00:05:33.519 --> 00:05:35.759 we found a system that is essentially looking at our 122 00:05:35.759 --> 00:05:37.480 physics textbooks and laughing. 123 00:05:37.800 --> 00:05:40.560 It's definitely curveable, a massive one. 124 00:05:40.639 --> 00:05:43.600 So today we are exploring a distant planetary system that 125 00:05:43.680 --> 00:05:46.560 is breaking all the rules, a system that is making 126 00:05:46.600 --> 00:05:50.519 astronomers question the very timeline of how worlds are actually born. 127 00:05:50.759 --> 00:05:53.759 And the system we're talking about is known as LAHS nineteen. 128 00:05:53.439 --> 00:05:55.319 Oh three LHS nineteen oh three. 129 00:05:55.480 --> 00:05:57.000 Right, And I really want to be clear about the 130 00:05:57.079 --> 00:05:59.920 stakes here for everyone listening. This isn't just about finding 131 00:06:00.160 --> 00:06:01.360 a weird planet. 132 00:06:01.160 --> 00:06:03.439 Right, because we find great planets all the time. 133 00:06:03.279 --> 00:06:06.519 We do diamond planets, lava worlds. But this is about 134 00:06:06.519 --> 00:06:09.759 finding a planet that, according to our standard models of 135 00:06:09.759 --> 00:06:13.160 accretion and migration, physically shouldn't exist where it does. 136 00:06:13.279 --> 00:06:15.199 It's an impossible object based on the rules we just 137 00:06:15.279 --> 00:06:15.600 laid out. 138 00:06:15.639 --> 00:06:20.040 It is an absolute enigma, and solving it requires us 139 00:06:20.040 --> 00:06:23.199 to completely abandon the idea that planetary systems are these 140 00:06:23.199 --> 00:06:26.439 static structures. We have to start treating them as dynamic, 141 00:06:26.600 --> 00:06:27.800 evolving timelines. 142 00:06:27.920 --> 00:06:30.600 I love that distinction. Space isn't just a place, it's 143 00:06:30.639 --> 00:06:33.959 a sequence of events. So here is the roadmap for 144 00:06:34.000 --> 00:06:37.759 our discussion today. We're going to transport ourselves to LHS 145 00:06:37.879 --> 00:06:40.600 nineteen oh three, just to set the scene. Then we 146 00:06:40.639 --> 00:06:43.000 are going to look at the impossible planet that was 147 00:06:43.040 --> 00:06:45.839 discovered by this massive international. 148 00:06:45.240 --> 00:06:47.759 Team, the twist in the story right, And. 149 00:06:47.720 --> 00:06:49.480 Then we're going to spend some serious time on the 150 00:06:49.480 --> 00:06:53.439 detective work because the researchers tried really, really hard to 151 00:06:53.439 --> 00:06:56.000 prove this planet was just a mistake in the data. 152 00:06:56.079 --> 00:06:58.360 They did everything they could to kill their own anomaly. 153 00:06:58.519 --> 00:07:01.800 And finally we will unpack the radical new theory of 154 00:07:01.920 --> 00:07:04.360 inside out formation that they propose to explain it. 155 00:07:04.360 --> 00:07:06.120 It is a classic scientific mystery. 156 00:07:06.240 --> 00:07:08.839 Let's start with the setting. Take us to LHS nineteen 157 00:07:08.879 --> 00:07:10.839 oh three. If I am looking out the window of 158 00:07:10.839 --> 00:07:13.560 my spaceship, what kind of star am I looking at? 159 00:07:13.759 --> 00:07:16.399 You are looking at a red dwarf star. Now, we 160 00:07:16.480 --> 00:07:20.000 often hear red dwarfs and think small dim, maybe a bit. 161 00:07:19.959 --> 00:07:21.879 Boring, just a little glowing ember. 162 00:07:21.920 --> 00:07:24.600 Right, But these are actually the most common stars in 163 00:07:24.639 --> 00:07:28.079 the entire galaxy. They're called m dwarfs. LHS nineteen oh 164 00:07:28.120 --> 00:07:31.240 three is smaller than our Sun, it's cooler than our Sun, 165 00:07:31.560 --> 00:07:33.079 and it is much much redder. 166 00:07:33.160 --> 00:07:36.199 So if it's cooler than the Goldilock zone. 167 00:07:35.879 --> 00:07:38.920 The habitable zone where water can be liquid. 168 00:07:38.600 --> 00:07:41.839 Yes, that zone would be much closer in than it 169 00:07:41.879 --> 00:07:43.720 is around our Sun, much closer. 170 00:07:43.759 --> 00:07:46.800 The entire scale of the system is sort of shrunken down. 171 00:07:47.240 --> 00:07:50.519 The planets are huddled closer to the fire, so to speak. 172 00:07:50.879 --> 00:07:53.879 But M dwarfs are also tricky. They can be very active, 173 00:07:54.040 --> 00:07:58.560 flaring violently, and that complicates the whole atmosphere tripping mechanic 174 00:07:58.560 --> 00:07:59.920 we talked about earlier, because. 175 00:07:59.680 --> 00:08:02.040 If it's it's growing out massive flares, it's going to 176 00:08:02.120 --> 00:08:04.639 blast away atmospheres even more aggressively. 177 00:08:04.879 --> 00:08:08.160 Exactly. Now, this system has been under surveillance for a while. 178 00:08:08.800 --> 00:08:11.120 This isn't a brand new star we just noticed, right. 179 00:08:11.160 --> 00:08:13.079 The team observing it has been at it for a bit. 180 00:08:13.120 --> 00:08:16.040 It's co led by researchers from McMaster University and the 181 00:08:16.120 --> 00:08:17.079 University of Warwick. 182 00:08:17.240 --> 00:08:20.439 Yes, and they've been doing incredible work using a combination 183 00:08:20.720 --> 00:08:24.639 of ground based telescopes and space based data to really 184 00:08:24.680 --> 00:08:27.439 understand the architecture of this specific system. 185 00:08:27.720 --> 00:08:30.360 And initially this system looked like it was following the rules. 186 00:08:30.439 --> 00:08:32.559 It was a good, law abiding star system. 187 00:08:33.000 --> 00:08:35.759 It really seemed to be. Before this recent discovery, we 188 00:08:35.799 --> 00:08:39.440 knew of three planets orbiting LHS nineteen oh three. Let's 189 00:08:39.440 --> 00:08:42.559 call them the original trio. Okay, the original trio, and 190 00:08:42.639 --> 00:08:47.320 their layout was incredibly comforting to astronomers because it perfectly 191 00:08:47.360 --> 00:08:48.840 matched the pattern we expected. 192 00:08:49.159 --> 00:08:51.799 Walk us through that inventory. What did the map look 193 00:08:51.919 --> 00:08:52.679 like originally? 194 00:08:53.039 --> 00:08:55.480 Well, closest to the star, you have the inner planet, 195 00:08:55.919 --> 00:08:59.240 and as expected, it is a rocky world. It's bathed 196 00:08:59.240 --> 00:09:02.679 in radiation and it's incredibly hot. It has a high density. 197 00:09:03.080 --> 00:09:05.279 It fits that inner zone profile perfectly. 198 00:09:05.519 --> 00:09:08.919 Check just like Mercury or Earth. Yeah, a rock near 199 00:09:09.000 --> 00:09:10.000 the star exactly. 200 00:09:10.639 --> 00:09:12.799 Then you move a little further out you find planet 201 00:09:12.840 --> 00:09:15.919 two and planet three, and these are not rocks. The 202 00:09:15.960 --> 00:09:19.080 team characterize them as miniature neptunes. 203 00:09:19.240 --> 00:09:21.600 Let's define that really quick. When we say mini neptune, 204 00:09:21.600 --> 00:09:23.519 we aren't talking about a water world. 205 00:09:23.559 --> 00:09:26.919 Are we not necessarily water? No, we are talking about 206 00:09:26.919 --> 00:09:29.960 planets that have a solid core, likely rock and ice, 207 00:09:30.200 --> 00:09:33.840 but they are enveloped in a very thick hydrogen and helium. 208 00:09:33.480 --> 00:09:36.159 Envelope, so they are gas dominated very much. 209 00:09:36.120 --> 00:09:38.639 So they have low densities. You couldn't land a spaceship 210 00:09:38.639 --> 00:09:40.639 on them. You would just sink through the cloud layers 211 00:09:40.799 --> 00:09:43.039 until the atmospheric pressure crushed you. 212 00:09:43.360 --> 00:09:46.840 Okay, so look at the map so far. Inner zone 213 00:09:47.080 --> 00:09:51.919 is a rock. Middle zone is gas. That sounds extremely familiar. 214 00:09:52.000 --> 00:09:54.600 It is the standard blueprint. You move away from the star, 215 00:09:55.039 --> 00:09:57.240 the temperature drops and the planets get gas. 216 00:09:57.279 --> 00:09:57.440 Here. 217 00:09:58.200 --> 00:10:01.519 If the survey had just stopped right there, LHS nineteen 218 00:10:01.519 --> 00:10:04.480 oh three would have been just another data point confirming 219 00:10:04.519 --> 00:10:05.399 the standard model. 220 00:10:05.559 --> 00:10:07.919 It would just be in a textbook as example a 221 00:10:08.080 --> 00:10:09.480 of normal planetary formation. 222 00:10:09.679 --> 00:10:12.919 It really would nothing to see here, folks. The physics works. 223 00:10:12.720 --> 00:10:15.399 But science is rarely that kind to us. The team 224 00:10:15.440 --> 00:10:16.360 didn't stop looking. 225 00:10:16.480 --> 00:10:19.159 They did not, and this is where the instrumentation really 226 00:10:19.159 --> 00:10:22.200 becomes the hero of the story. They utilize the European 227 00:10:22.240 --> 00:10:24.559 Space Agencies CHIOPS satellite. 228 00:10:24.639 --> 00:10:26.559 I really want to pause on CHIOPS because it's not 229 00:10:26.600 --> 00:10:29.639 as famous as Hubble or the James Webb Space Telescope, 230 00:10:29.720 --> 00:10:31.840 but for this specific kind of detective work. It is 231 00:10:31.879 --> 00:10:33.080 an absolute beast. 232 00:10:33.159 --> 00:10:35.960 It is a total marvel of engineering. CHOPS stands for 233 00:10:36.159 --> 00:10:40.120 characterizing exoplanet satellite. And note the word characterizing, right. 234 00:10:40.159 --> 00:10:42.919 It's not a discovery tool primarily exactly. 235 00:10:43.320 --> 00:10:46.159 It isn't a hunter like the Kepler telescope was, you know, 236 00:10:46.559 --> 00:10:50.360 scanning thousands of stars just looking for random blips. Cheops 237 00:10:50.720 --> 00:10:53.600 is a sniper. It stares at stars we already know 238 00:10:53.679 --> 00:10:54.360 have planets. 239 00:10:54.440 --> 00:10:56.960 Why dedicate a whole satellite to stare at something we've 240 00:10:56.960 --> 00:10:57.639 already found. 241 00:10:57.720 --> 00:11:03.799 Precision, it's all about precision. Uses ultra high precision transit photometry. 242 00:11:03.279 --> 00:11:04.759 Meaning it watches the shadow. 243 00:11:04.919 --> 00:11:07.200 Right, It measures the tiny dip in light as a 244 00:11:07.240 --> 00:11:10.159 planet crosses the face of the star. But it does 245 00:11:10.200 --> 00:11:13.559 this with such extreme sensitivity that it can determine the 246 00:11:13.600 --> 00:11:16.919 exact radius of a planet to a refined degree that 247 00:11:17.039 --> 00:11:19.840 ground based telescopes simply cannot match. 248 00:11:20.000 --> 00:11:23.519 Because ground telescopes have to look through Earth's messy atmosphere. 249 00:11:23.600 --> 00:11:27.559 Exactly, the atmosphere blurs the starlight. CHOPS is above all that. 250 00:11:27.840 --> 00:11:31.240 So it's the difference between seeing a blurry shadow passed 251 00:11:31.240 --> 00:11:34.679 by a frosted window versus seeing the crisp silhouette of 252 00:11:34.679 --> 00:11:37.519 a specific person and knowing exactly what kind of hat 253 00:11:37.559 --> 00:11:38.159 they're wearing. 254 00:11:38.399 --> 00:11:41.000 That is a very fair analogy. And this precision is 255 00:11:41.080 --> 00:11:44.720 vital because it allows us to calculate density properly. If 256 00:11:44.759 --> 00:11:47.279 you know the exact size from the transit shadow, and 257 00:11:47.360 --> 00:11:50.279 you know the mass from other methods, like how much 258 00:11:50.320 --> 00:11:52.000 the planet's gravity makes the star. 259 00:11:51.879 --> 00:11:55.120 Wobble the radial velocity exactly. 260 00:11:54.879 --> 00:11:57.159 You can bind size and mass and you get density, 261 00:11:57.480 --> 00:11:59.279 and density tells you if you are looking at a 262 00:11:59.320 --> 00:12:01.279 dense rock or a flicky cloud. 263 00:12:01.399 --> 00:12:04.559 So chi Ops is just staring at LHS nineteen oh three, 264 00:12:04.879 --> 00:12:08.159 refining the data on those three known planets, just doing 265 00:12:08.159 --> 00:12:09.600 its job, and then. 266 00:12:09.559 --> 00:12:12.039 A blip, a blip, a fourth signal in the data. 267 00:12:12.559 --> 00:12:16.039 After years of characterization efforts, the light curve revealed a 268 00:12:16.080 --> 00:12:20.799 completely new fourth world. It has been designated LHS nineteen oh. 269 00:12:20.759 --> 00:12:23.840 Three E planet E. Okay, So, now, knowing what we 270 00:12:23.960 --> 00:12:26.399 know about the Standard Model and knowing that we already 271 00:12:26.399 --> 00:12:28.559 have rocks on the inside and gas on the outside 272 00:12:28.559 --> 00:12:30.840 in the system, where's this new planet located? 273 00:12:30.919 --> 00:12:34.240 That is the multimillion dollar question. LHS nineteen oh three 274 00:12:34.279 --> 00:12:36.960 is the farthest planet from the star. It orbits way 275 00:12:36.960 --> 00:12:39.279 outside the path of those two mini Neptunes. 276 00:12:39.399 --> 00:12:41.399 Okay, so we are in the deep outer zone. We 277 00:12:41.480 --> 00:12:43.799 are well past the frost line. We are in the freezer. 278 00:12:43.919 --> 00:12:46.240 Correct. We are out in the region where the protoplanetary 279 00:12:46.279 --> 00:12:49.600 disc should have been cool, calm, and incredibly rich in 280 00:12:49.679 --> 00:12:50.679 volatiles and gas. 281 00:12:50.960 --> 00:12:53.519 So, by every law of physics we discussed earlier, planet 282 00:12:53.639 --> 00:12:56.360 E should be a gas giant. Absolutely, it should be 283 00:12:56.399 --> 00:12:58.840 another mini Neptune, or maybe even a full Neptune. It 284 00:12:58.840 --> 00:13:01.000 should have scooped up all that cold gas. 285 00:13:01.200 --> 00:13:05.480 That is the overwhelming expectation. But when the team crunched 286 00:13:05.480 --> 00:13:08.759 the density numbers from the CHIOPS data, the result was 287 00:13:09.039 --> 00:13:14.519 completely unambiguous. LHS nineteen oh three. E is not a 288 00:13:14.559 --> 00:13:15.120 gas giant. 289 00:13:15.200 --> 00:13:15.679 Don't tell me. 290 00:13:15.840 --> 00:13:17.080 It is a rocky planet. 291 00:13:17.200 --> 00:13:17.960 That makes no sense. 292 00:13:18.000 --> 00:13:21.039 It makes absolutely zero sense under the core accretion model. 293 00:13:21.240 --> 00:13:24.919 Let's visualize this planetary sandwich. We have the star, then 294 00:13:24.960 --> 00:13:28.840 a rock, then gas, then more gas, and then way 295 00:13:28.879 --> 00:13:30.080 out in the cold another rock. 296 00:13:30.279 --> 00:13:33.000 Exactly. It's like walking out into the ocean, getting past 297 00:13:33.039 --> 00:13:36.080 the crashing breakers, swimming way out into the deep water, 298 00:13:36.279 --> 00:13:38.200 and suddenly you just step on dry land. 299 00:13:38.360 --> 00:13:41.519 Wow. Why is this physically impossible though? I mean, obviously 300 00:13:41.600 --> 00:13:44.320 rocks can exist anywhere, right, Asteroids are rocks out in 301 00:13:44.360 --> 00:13:46.840 the cold. Pluter is mostly rock and iceed. Why can't 302 00:13:46.840 --> 00:13:48.519 a full planet be a rock out there? 303 00:13:48.639 --> 00:13:51.600 It's all about mass and gravity. To be a planet 304 00:13:51.639 --> 00:13:53.679 of this size, and Planet E is what we call 305 00:13:53.679 --> 00:13:56.720 a super Earth, so it's substantial. You have to form 306 00:13:56.759 --> 00:13:59.720 a core that is roughly five to ten times the 307 00:13:59.720 --> 00:14:03.240 mass of Earth. Okay, and once a protoplanet reaches that 308 00:14:03.279 --> 00:14:07.559 specific mass threshold, its gravity becomes too strong. It automatically 309 00:14:07.600 --> 00:14:10.240 starts holding onto hydrogen and helium gas. 310 00:14:10.360 --> 00:14:12.240 It becomes that vacuum cleaner we talked. 311 00:14:12.080 --> 00:14:16.200 About yes, and out in that orbit during formation there 312 00:14:16.279 --> 00:14:18.799 should have been plenty of gas to vacuum up. So 313 00:14:18.879 --> 00:14:20.840 if it formed there and it got big enough to 314 00:14:20.840 --> 00:14:23.759 be a super Earth, it must have an atmosphere. Physics 315 00:14:23.799 --> 00:14:26.000 demands it, but it doesn't. It doesn't. The fact that 316 00:14:26.039 --> 00:14:29.039 it is naked, just a bare rock, implies that something 317 00:14:29.120 --> 00:14:32.600 stopped the vacuum cleaner from working, or there was simply 318 00:14:32.600 --> 00:14:33.600 nothing to vacuum. 319 00:14:33.679 --> 00:14:36.440 This is the massive friction point for astronomers. You have 320 00:14:36.519 --> 00:14:39.240 a huge core sitting in what should be a gas 321 00:14:39.399 --> 00:14:42.399 rich environment, but it has no gas. It's like finding 322 00:14:42.399 --> 00:14:44.559 a sponge at the bottom of a swimming pool that 323 00:14:44.639 --> 00:14:46.000 is completely bone dry. 324 00:14:46.159 --> 00:14:48.639 That is the perfect image for it, and that dry 325 00:14:48.720 --> 00:14:52.159 sponge forced the research team to play detective. They couldn't 326 00:14:52.200 --> 00:14:54.279 just publish a paper and say, well, physics. 327 00:14:54.000 --> 00:14:56.000 Is broken, right, They'd be laughed out of the room. 328 00:14:56.120 --> 00:14:59.360 They had to rule out every other conceivable explanation. First. 329 00:14:59.600 --> 00:15:02.039 They had to to prove this wasn't just a misinterpretation 330 00:15:02.120 --> 00:15:02.960 of normal events. 331 00:15:03.639 --> 00:15:07.240 So let's enter the CSI exoplanet phase of our discussion. 332 00:15:07.919 --> 00:15:10.320 When you find an anomaly like this, you have to 333 00:15:10.360 --> 00:15:13.120 assume you were just missing a piece of the history, 334 00:15:13.519 --> 00:15:16.399 and the first assumption in astronomy is usually that something 335 00:15:16.519 --> 00:15:17.320 violent happened. 336 00:15:17.440 --> 00:15:20.879 Violence is definitely a common theme in planetary history. So 337 00:15:20.919 --> 00:15:25.440 the first theory the team tested was the giant impact hypothesis, right. 338 00:15:25.480 --> 00:15:27.960 The idea that planet Ease actually was a gas giant 339 00:15:28.000 --> 00:15:30.720 once it followed the rules, it had a thick atmosphere, 340 00:15:30.960 --> 00:15:32.799 and then wham exactly. 341 00:15:33.000 --> 00:15:35.639 The theory posits that the planet formed correctly as a 342 00:15:35.679 --> 00:15:39.799 meaning neptune, but then a massive object, perhaps a rogue 343 00:15:39.799 --> 00:15:44.759 planetary embryo or a huge asteroid struck it with unbelievable energy. 344 00:15:44.600 --> 00:15:47.120 Enough energy to just blast the atmosphere away. 345 00:15:46.960 --> 00:15:50.120 Into space right leaving only the dense rocky core behind. 346 00:15:50.600 --> 00:15:53.559 Now this sounds highly plausible to me. We know impacts 347 00:15:53.600 --> 00:15:56.759 happen all the time. Our own moon, formed from a 348 00:15:56.799 --> 00:16:00.559 Mars sized object hitting Earth. Uranus is tipped completely on 349 00:16:00.639 --> 00:16:04.799 its side, probably because of a massive impact. Why couldn't 350 00:16:04.799 --> 00:16:05.799 that be the answer here? 351 00:16:05.919 --> 00:16:09.759 It comes down to the energy budget. Stripping an entire 352 00:16:09.879 --> 00:16:13.320 planetary atmosphere, especially one held by the gravity of a 353 00:16:13.399 --> 00:16:16.799 super Earth, requires a cataclysmic amount of energy. 354 00:16:17.039 --> 00:16:18.559 It's not just a little fender bender. 355 00:16:18.840 --> 00:16:21.679 No, we aren't talking about a dinosaur killer asteroid. We 356 00:16:21.720 --> 00:16:25.279 are talking about a direct collision with another planet sized 357 00:16:25.320 --> 00:16:27.480 object traveling at immense. 358 00:16:27.120 --> 00:16:29.320 Speed, a planetary demolition derby. 359 00:16:29.440 --> 00:16:32.240 Yes, and when you run the numerical simulations of that 360 00:16:32.320 --> 00:16:35.759 kind of collision, you immediately run into major problems. First, 361 00:16:35.759 --> 00:16:36.799 it's just the probability. 362 00:16:36.840 --> 00:16:37.480 It's too rare. 363 00:16:37.600 --> 00:16:40.159 A collision that is precise enough to cleanly strip the 364 00:16:40.200 --> 00:16:43.200 gas away but somehow leave the rocky core completely intact 365 00:16:43.440 --> 00:16:47.200 in a stable orbit is vanishingly rare. Usually, you shatter 366 00:16:47.320 --> 00:16:48.279 the planet entirely. 367 00:16:48.360 --> 00:16:50.600 Okay, what's the second problem, where is the debris? 368 00:16:51.320 --> 00:16:54.320 A collision of that magnitude creates a massive debris disk, 369 00:16:55.039 --> 00:16:59.080 millions of fragments, dust, shattered crust, and all that dust 370 00:16:59.120 --> 00:17:02.440 would absorb star light and glow brightly in the infrared spectrum. 371 00:17:02.480 --> 00:17:04.119 Oh and we don't see any glowing dust. 372 00:17:04.599 --> 00:17:07.359 The system is completely clean. Furthermore, the current orbit of 373 00:17:07.400 --> 00:17:11.839 planet E is relatively circular and stable. A massive atmosphere 374 00:17:11.880 --> 00:17:15.720 destroying impact usually perturbs the orbit significantly. It makes it 375 00:17:15.799 --> 00:17:19.359 highly elliptical or wildly inclined compared to the other planets. 376 00:17:19.480 --> 00:17:21.359 So the forensic evidence just isn't there. 377 00:17:21.480 --> 00:17:24.279 It's not the blood spatter pattern to keep the CSI 378 00:17:24.319 --> 00:17:27.200 analogy going just didn't match a murder scene. 379 00:17:27.279 --> 00:17:30.640 Okay, so suspect number one, the giant impact, is released 380 00:17:30.640 --> 00:17:33.480 for lack of evidence. What about suspect number two? Because 381 00:17:33.519 --> 00:17:35.519 this one honestly seems the most likely to me. 382 00:17:36.240 --> 00:17:40.559 Migration, ah, planetary migration. This is really the darling of 383 00:17:40.599 --> 00:17:44.119 modern exoplanet science. We know for a fact that planets move. 384 00:17:44.440 --> 00:17:47.039 We are fairly certain Jupiter migrated in our own Solar 385 00:17:47.079 --> 00:17:47.960 system early on. 386 00:17:48.119 --> 00:17:51.880 Right, So the theory here simple planet e wasn't born 387 00:17:51.920 --> 00:17:54.200 in the outer zone. It was born in the inner zone, 388 00:17:54.240 --> 00:17:57.839 the rock factory, right where it belongs, and then through 389 00:17:57.839 --> 00:18:00.680 gravitational pinball, it got kicked out the suburbs. 390 00:18:01.039 --> 00:18:05.000 It's the drifting rock hypothesis. It formed inside the frost 391 00:18:05.039 --> 00:18:08.599 line as a normal rocky planet and then migrated outward 392 00:18:08.759 --> 00:18:12.200 over millions of years. This would explain perfectly why it 393 00:18:12.240 --> 00:18:14.359 is rocky. It was baked in the oven and then 394 00:18:14.400 --> 00:18:15.519 simply move to the freezer. 395 00:18:15.720 --> 00:18:17.720 So why did the team rule this out? It sounds 396 00:18:17.720 --> 00:18:18.960 like the perfect alibi. 397 00:18:19.240 --> 00:18:23.319 It fails the gravitational fingerprint test. You see, when planets migrate, 398 00:18:23.440 --> 00:18:26.400 they do not slide silently through the night. They interact 399 00:18:26.440 --> 00:18:28.799 gravitationally with absolutely everything they pass. 400 00:18:28.920 --> 00:18:31.599 Because they are heavy, they drag things around exactly. 401 00:18:31.640 --> 00:18:35.720