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 --> 00:00:23.839 slumber under the night sky. 7 00:00:26.879 --> 00:00:28.440 I want you to close your eyes for a second. 8 00:00:28.440 --> 00:00:30.199 We're going to do something a little dark to start 9 00:00:30.239 --> 00:00:30.960 things off today. 10 00:00:31.079 --> 00:00:32.240 Oh I'm intrigued. 11 00:00:32.399 --> 00:00:36.119 I want you to imagine the absolute worst case scenario. 12 00:00:36.719 --> 00:00:39.399 And I'm not talking about a stock market crash or 13 00:00:39.399 --> 00:00:43.039 a hurricane, or even a zombie apocalypse. I'm talking about 14 00:00:43.079 --> 00:00:47.439 the ultimate cosmic end game, the big one, the death 15 00:00:47.439 --> 00:00:48.399 of a solar system. 16 00:00:48.640 --> 00:00:53.719 It is a scale of destruction that is genuinely hard 17 00:00:53.799 --> 00:00:56.079 for the human mind to process. I mean, we are 18 00:00:56.119 --> 00:00:58.759 talking about physics on a scale that makes our most 19 00:00:58.759 --> 00:01:02.119 powerful nuclear weapons look like tiny firecrackers popping in the 20 00:01:02.159 --> 00:01:03.280 distance exactly. 21 00:01:03.759 --> 00:01:06.400 And I think when most people picture this the end 22 00:01:06.439 --> 00:01:08.359 of the world or the end of a star system, 23 00:01:08.680 --> 00:01:10.079 they think of science chittus. 24 00:01:10.000 --> 00:01:10.400 A death star. 25 00:01:10.519 --> 00:01:12.280 You think of the death star, right it's a giant 26 00:01:12.319 --> 00:01:15.680 laser beam, a sudden green flash and explosion and boom, 27 00:01:15.760 --> 00:01:20.680 the planet has gone instant darkness. But the reality, the 28 00:01:20.719 --> 00:01:23.920 actual science of it, is actually much slower and much 29 00:01:23.959 --> 00:01:26.439 more insidious, and honestly, it is a lot scarier. 30 00:01:26.599 --> 00:01:27.879 It is not an explosion. 31 00:01:27.959 --> 00:01:28.760 It's a suffocation. 32 00:01:28.959 --> 00:01:30.959 That is a very very apt way to put it. 33 00:01:30.959 --> 00:01:35.120 It's the slow, inevitable swelling of a star, the transition 34 00:01:35.200 --> 00:01:36.280 to the red giant phase. 35 00:01:36.359 --> 00:01:40.519 The red giant just the name sounds menacing. Picture of 36 00:01:40.640 --> 00:01:44.239 star are maybe running out of fuel. It gets angry, 37 00:01:44.280 --> 00:01:47.840 It starts expanding outward like a balloon being overinflated. It 38 00:01:47.920 --> 00:01:53.599 swallows everything in its path. Mercury gone, Venus toast toast. 39 00:01:53.920 --> 00:01:56.079 Earth will get to Earth later. And it's not a 40 00:01:56.079 --> 00:01:58.400 pretty picture. But for a long time, the assumption in 41 00:01:58.480 --> 00:02:01.359 astronomy was that this is basically a death sentence for 42 00:02:01.400 --> 00:02:04.159 the entire neighborhood. If your star goes red giant, it's 43 00:02:04.200 --> 00:02:04.599 game over. 44 00:02:04.840 --> 00:02:08.280 That has been the prevailing wisdom for decades. When a 45 00:02:08.319 --> 00:02:12.000 star sheds its outer layers and swells up, the gravitational 46 00:02:12.000 --> 00:02:14.560 and thermal forces are so extreme that we generally assume 47 00:02:14.599 --> 00:02:16.240 planetary systems are wiped clean. 48 00:02:16.400 --> 00:02:18.280 The slate is wipe blank exactly. 49 00:02:18.319 --> 00:02:22.080 The star expands, consumes the inner planets, destabilizes the outer ones, 50 00:02:22.199 --> 00:02:23.360 and leaves nothing but dust. 51 00:02:23.439 --> 00:02:26.199 But and this is why we are here today. There's 52 00:02:26.240 --> 00:02:29.560 a twist, you plot twist in the story of stellar death. 53 00:02:29.680 --> 00:02:33.759 H It turns out not everyone dies. There are survivors, 54 00:02:33.840 --> 00:02:38.680 party survivors, and that is the mystery we are unpacking today. 55 00:02:38.800 --> 00:02:41.719 How do you survive being swallowed or scorched by your 56 00:02:41.719 --> 00:02:46.039 own son? And more importantly, who are these survivors? Because 57 00:02:46.080 --> 00:02:49.159 we have some brand new informations literally hot off the breast, 58 00:02:49.840 --> 00:02:51.439 that changes how we look at this. 59 00:02:52.080 --> 00:02:54.319 It really is brand new. I mean we are looking 60 00:02:54.360 --> 00:02:57.960 into data that came out essentially yesterday, February fourth, twenty 61 00:02:58.039 --> 00:02:58.560 twenty six. 62 00:02:58.800 --> 00:03:01.240 It doesn't get fresher than that. Yeah, So what are 63 00:03:01.280 --> 00:03:02.439 we looking at? What's the source? 64 00:03:02.560 --> 00:03:05.360 This is a new study published in Astronomy and Astrophysics 65 00:03:05.479 --> 00:03:09.439 and it's currently making waves on the ARCSIV server. The 66 00:03:09.439 --> 00:03:14.319 title is predicted incidents of Jupiter like planets around white dwarfs. 67 00:03:14.360 --> 00:03:17.280 Predicted incidents. It's very polite. 68 00:03:17.400 --> 00:03:19.520 Academic titles always hide at the drama, don't they. But 69 00:03:19.560 --> 00:03:22.439 the lead author is alex Mars Soriano from the DEPARTMENTA 70 00:03:22.479 --> 00:03:25.479 of Phisica at the University DoD Technica Federico Santa Maria 71 00:03:25.520 --> 00:03:29.319 in Valpariso, Chile, Okay. And what they have done is fascinating. 72 00:03:29.319 --> 00:03:31.520 They haven't just looked for these planets with a telescope, 73 00:03:31.759 --> 00:03:35.039 They've built a comprehensive simulation of the Milky Way to 74 00:03:35.120 --> 00:03:35.879 predict them. 75 00:03:36.120 --> 00:03:38.520 So our mission today is to look at this census 76 00:03:38.599 --> 00:03:41.240 of the survivors. We want to know, out of all 77 00:03:41.240 --> 00:03:45.039 the planets that face this fiery apocalypse, how many actually 78 00:03:45.039 --> 00:03:46.479 make it through to the other side. 79 00:03:46.560 --> 00:03:49.199 And we aren't just looking at pretty pictures of space here, 80 00:03:49.280 --> 00:03:51.479 we are digging into the physics. Yeah, we need to 81 00:03:51.479 --> 00:03:55.599 figure out exactly how rare these survivor planets are. Are 82 00:03:55.599 --> 00:03:57.639 they one in a million, one in ten? 83 00:03:57.840 --> 00:04:02.439 Right? And why does one planet survive while its neighbor 84 00:04:02.520 --> 00:04:04.000 gets completely vaporized? 85 00:04:04.159 --> 00:04:07.400 And here is the So what for you listening right now? 86 00:04:07.840 --> 00:04:10.599 This isn't just about some distant star light years away. 87 00:04:10.680 --> 00:04:11.520 This is a preview. 88 00:04:11.759 --> 00:04:12.360 It's a trailer. 89 00:04:12.439 --> 00:04:15.240 It's a trailer for the future of our own Solar system. 90 00:04:15.319 --> 00:04:17.920 We are basically looking at the fate of Jupiter and Saturn. 91 00:04:18.079 --> 00:04:22.240 That is exactly right. By studying these distant systems, we 92 00:04:22.319 --> 00:04:25.279 are essentially looking into a crystal ball for our own neighborhood. 93 00:04:25.600 --> 00:04:28.600 We're seeing our own future played out on a galactic stage. 94 00:04:28.720 --> 00:04:31.680 Yeah, future, that's about what five six billion years away, 95 00:04:31.839 --> 00:04:33.879 But still it's written in the stars. 96 00:04:34.120 --> 00:04:36.439 So let's unpack this. Before we get to the survivors. 97 00:04:36.439 --> 00:04:39.319 We have to understand the killer. We need to talk 98 00:04:39.319 --> 00:04:45.399 about the mechanism of destruction. Why is survival so incredibly hard? 99 00:04:45.439 --> 00:04:48.079 To understand the destruction, you have to understand the life 100 00:04:48.079 --> 00:04:52.120 cycle of a star. Most stars, like our Sun, spend 101 00:04:52.160 --> 00:04:54.399 the vast majority of their lives in what we call 102 00:04:54.439 --> 00:04:55.279 the main sequence. 103 00:04:55.399 --> 00:04:58.399 That's the happy, stable time, the prime of life. 104 00:04:58.480 --> 00:05:02.279 Correct, it's burning hydro into helium in its core. It's stable. 105 00:05:02.560 --> 00:05:05.040 Gravity is pulling in trying to crush the star, but 106 00:05:05.120 --> 00:05:07.439 the energy from fusion is pushing out, and everything is 107 00:05:07.480 --> 00:05:11.120 in a perfect hydrostatic balance, a standoff. It's a standoff 108 00:05:11.199 --> 00:05:15.160 between two tightened forces, and as long as there is fuel, 109 00:05:15.240 --> 00:05:18.759 the standoff holds. But eventually the hydrogen runs. 110 00:05:18.560 --> 00:05:20.800 Out, the fuel tank gets empty, and when the gas 111 00:05:20.800 --> 00:05:23.519 tank is empty in a car, the car stops. 112 00:05:23.240 --> 00:05:25.480 Right in a car, Yes, in a star, it's the opposite. 113 00:05:25.519 --> 00:05:27.680 When the fuel runs out in the core, the engine 114 00:05:27.680 --> 00:05:31.079 goes haywire. Core starts to collapse because there's no outward 115 00:05:31.079 --> 00:05:33.199 pressure to hold it up to more. But as the 116 00:05:33.199 --> 00:05:37.079 core collapses, it gets hotter, much much hotter. This new 117 00:05:37.240 --> 00:05:41.360 intense heat pushes the outer layers of the star away, so. 118 00:05:41.279 --> 00:05:43.600 The outer parts stop listening to gravity. 119 00:05:43.680 --> 00:05:47.839 They stop listening to gravity, they start to expand drastically. 120 00:05:48.360 --> 00:05:51.720 The star transitions from a main sequence star into a 121 00:05:51.839 --> 00:05:52.560 red giant. 122 00:05:52.600 --> 00:05:55.240 I always like the analogy of a marshmallow in a microwave. 123 00:05:55.759 --> 00:05:57.759 That is surprisingly accurate. 124 00:05:57.959 --> 00:05:59.519 Go on, you know what I mean. You put a 125 00:05:59.560 --> 00:06:02.240 regular hence marshmallow and you hit start. It heats up 126 00:06:02.240 --> 00:06:05.680 from the inside and it just starts expanding. It gets huge, 127 00:06:05.720 --> 00:06:08.000 it gets fluffy, It takes up the whole microwave. 128 00:06:08.079 --> 00:06:10.560 But unlike a marshmallow, which is delicious. 129 00:06:10.160 --> 00:06:14.680 A red giant is incredibly dangerous. If you are orbiting nearby. 130 00:06:14.480 --> 00:06:17.319 It is lethal. The radius of the star can increase 131 00:06:17.360 --> 00:06:20.000 by a factor of one hundred or even more. Our 132 00:06:20.079 --> 00:06:22.439 Sun will swell up to roughly the orbit of Earth. 133 00:06:22.600 --> 00:06:25.839 It physically takes up more space and This leads to 134 00:06:25.879 --> 00:06:28.480 the three ways a planet can die, the three. 135 00:06:28.319 --> 00:06:31.360 Methods of execution. Let's go through them, because this really 136 00:06:31.399 --> 00:06:33.959 sets the stakes. It's not just one thing that kills you. 137 00:06:34.240 --> 00:06:35.240 It's a triple threat. 138 00:06:35.360 --> 00:06:38.920 The first and most obvious is engulfment, which is just 139 00:06:38.959 --> 00:06:41.240 what it sounds like. It's exactly what it sounds like. 140 00:06:41.639 --> 00:06:46.199 The star physically expands past the planet's orbit. The planet 141 00:06:46.240 --> 00:06:49.439 literally flies inside the star's atmosphere, and. 142 00:06:49.360 --> 00:06:52.279 Space is a vacuum, so there's usually no friction. But 143 00:06:52.560 --> 00:06:55.560 inside a star, that's a different story. 144 00:06:55.600 --> 00:06:57.720 It's a very different story. It's gas. It's thick. The 145 00:06:57.759 --> 00:07:00.600 friction from the gas the drag. It slows the planet down, 146 00:07:00.920 --> 00:07:05.959 it loses orbital speed, spirals into the core, and is obliterated. Wow, 147 00:07:06.160 --> 00:07:08.639 this is the likely fate of mercury and venus in 148 00:07:08.680 --> 00:07:11.439 our own system. They will simply be swallowed whole. 149 00:07:11.360 --> 00:07:14.759 And possibly Earth. But we'll pinachaotic maybe on that for now. 150 00:07:15.639 --> 00:07:18.879 So that's engulfment being eaten alive. What's the second way 151 00:07:18.920 --> 00:07:19.199 to die? 152 00:07:19.319 --> 00:07:21.920 Tidal forces? This one is a bit more subtle, but 153 00:07:21.959 --> 00:07:22.319 just as. 154 00:07:22.240 --> 00:07:24.240 Destructive, like the tides of the ocean. 155 00:07:24.000 --> 00:07:28.079 Same principle, but on a mind boggling scale. As the 156 00:07:28.120 --> 00:07:31.879 star loses mass because it's puffing out these layers into space, 157 00:07:32.000 --> 00:07:34.959 it's gravity changes. But also because the star is so 158 00:07:35.079 --> 00:07:37.920 huge and you're so close, the gravitational pull on the 159 00:07:37.959 --> 00:07:40.519 side of the planet facing the star is much stronger than. 160 00:07:40.399 --> 00:07:42.600 The pole on the far side, so it gets stretched. 161 00:07:42.519 --> 00:07:45.480 Ripped apart. Really, we call this spaghettification when we talk 162 00:07:45.519 --> 00:07:49.079 about black holes, but a similar thing happens here. These 163 00:07:49.120 --> 00:07:53.480 intense gravitational poles can physically disassemble a planet before it 164 00:07:53.560 --> 00:07:54.519 even gets engulfed. 165 00:07:54.639 --> 00:07:56.639 It just crumbles under the stress. 166 00:07:56.800 --> 00:07:59.519 The planet's own gravity isn't strong enough to hold it 167 00:07:59.560 --> 00:08:02.199 together against the pull of the star. It's like pulling 168 00:08:02.279 --> 00:08:03.480 a piece of bread apart. 169 00:08:03.639 --> 00:08:05.720 Okay, so you can be eaten or you can be 170 00:08:05.800 --> 00:08:08.279 ripped to shreds. Not great options. 171 00:08:08.800 --> 00:08:13.199 And the third vaporization, the transition from a main sequence 172 00:08:13.240 --> 00:08:17.480 star to a red giant involves intense heat spikes. The luminosity, 173 00:08:17.519 --> 00:08:20.600 the brightness of the star skyrockets, so it's not just bigger, 174 00:08:20.680 --> 00:08:23.959 it's also hotter incredibly, so the radiation can be so 175 00:08:24.079 --> 00:08:27.439 intense that it boils the planet away. It strips the atmosphere, 176 00:08:27.480 --> 00:08:30.120 then boils the oceans and melts the rock. It's like 177 00:08:30.199 --> 00:08:32.480 holding a candle to an ice cube, but the candle 178 00:08:32.559 --> 00:08:34.799 is a star and the ice cube is a planet. 179 00:08:35.159 --> 00:08:37.799 So it's a gauntlet you have to dodge being eaten, 180 00:08:37.879 --> 00:08:39.240 being torn apart, and being. 181 00:08:39.039 --> 00:08:42.720 Boiled precisely, And if a planet manages to survive all 182 00:08:42.759 --> 00:08:45.919 of that, if it survives the red giant phase, the 183 00:08:45.960 --> 00:08:49.360 star eventually sheds all those outer pucky layers. 184 00:08:49.399 --> 00:08:49.960 Where do they go? 185 00:08:50.200 --> 00:08:53.200 They drift away into space, creating what we call a 186 00:08:53.240 --> 00:08:57.799 planetary nebula, which ironically is often beautiful to look at. 187 00:08:57.960 --> 00:09:01.679 I've seen pictures. They're gorgeous, but it's really a stellar graveyard. 188 00:09:01.799 --> 00:09:04.799 It is, and what is left behind is the core, 189 00:09:05.320 --> 00:09:08.279 a dense, hot, tiny remnant called. 190 00:09:08.039 --> 00:09:10.720 A white dwarf, the corpse of the star. 191 00:09:10.639 --> 00:09:14.039 A very hot corpse, but yes, about the size of Earth, 192 00:09:14.120 --> 00:09:16.639 but with the mass of the Sun, incredibly dense. A 193 00:09:16.639 --> 00:09:18.519 teaspoon of it would weigh tons. 194 00:09:18.960 --> 00:09:20.879 So if we look up at the sky with our 195 00:09:20.919 --> 00:09:23.519 telescopes and we see a white dwarf and we see 196 00:09:23.519 --> 00:09:26.559 a planet orbiting it, that planet is a veteran. 197 00:09:26.879 --> 00:09:30.360 It is a survivor of a stellar war. It witnessed 198 00:09:30.399 --> 00:09:33.399 the expansion. It survived the tides, it endured the heat, 199 00:09:33.519 --> 00:09:35.799 and it is still standing. It has a story to tell. 200 00:09:36.200 --> 00:09:38.159 That makes them incredibly special. It means they have a 201 00:09:38.200 --> 00:09:40.519 story to tell. But for a long time, we didn't 202 00:09:40.519 --> 00:09:42.559 know if any planets actually could survive this. It was 203 00:09:42.600 --> 00:09:44.919 all theoretical math on a chalkboard exactly. 204 00:09:44.960 --> 00:09:47.440 We had the models, but we didn't have the proof, 205 00:09:47.639 --> 00:09:50.440 so we were just guessing. We were guessing until about 206 00:09:50.480 --> 00:09:53.480 fifteen years ago. We hoped they existed, but we hadn't 207 00:09:53.519 --> 00:09:55.559 seen one. We weren't sure it was even possible. 208 00:09:55.840 --> 00:09:58.639 But then we found evidence, and this takes us to 209 00:09:58.679 --> 00:10:01.320 the second part of our journey. Today we know they exist. 210 00:10:01.360 --> 00:10:02.679 This isn't just math anymore. 211 00:10:02.799 --> 00:10:06.279 No, we have direct observations. The first major clue came 212 00:10:06.320 --> 00:10:07.799 back in twenty eleven. 213 00:10:08.120 --> 00:10:10.440 Take us back to twenty eleven. What did they find? 214 00:10:10.879 --> 00:10:15.320 Astronomers discovered an exoplanet orbiting a white dwarf. It was massive, 215 00:10:15.559 --> 00:10:17.480 about eight times the mass of Jupiter. 216 00:10:17.679 --> 00:10:19.799 That is a beast of a planet that's bordering on 217 00:10:19.840 --> 00:10:22.039 a brown dwarf. Isn't it one of those failed stars? 218 00:10:22.240 --> 00:10:25.039 It's getting there but still classified as a planet. But 219 00:10:25.080 --> 00:10:27.879 the key detail wasn't its size, it was its location. 220 00:10:28.559 --> 00:10:30.960 It was orbiting at a distance of about twenty five 221 00:10:31.080 --> 00:10:33.159 hundred astronomical units AU. 222 00:10:33.440 --> 00:10:36.000 Okay, let's put that in respective for everyone. One AU 223 00:10:36.320 --> 00:10:38.080 is the distance from the Earth to the Sun. That's 224 00:10:38.080 --> 00:10:41.279 our yardstick. Jupiter is about five AU out right. 225 00:10:41.120 --> 00:10:43.320 And Pluto, which we all think of as being way 226 00:10:43.320 --> 00:10:46.639 out there, is about forty AU on average. 227 00:10:46.200 --> 00:10:48.960 And the voyager probes the furthest things humans have ever 228 00:10:49.000 --> 00:10:51.159 sent are only about one hundred and fifty to one 229 00:10:51.240 --> 00:10:53.320 hundred and sixty AU out right now, and they've been 230 00:10:53.320 --> 00:10:54.240 traveling for decades. 231 00:10:54.240 --> 00:10:57.000 So this thing at twenty five hundred AU was way 232 00:10:57.039 --> 00:10:57.679 way out there. 233 00:10:57.759 --> 00:11:00.600 That is lonely. That is deep deep space, that is 234 00:11:00.679 --> 00:11:02.519 practically in the interstellar void. 235 00:11:02.840 --> 00:11:07.000 It is incredibly far, but that distance is exactly why 236 00:11:07.039 --> 00:11:10.600 it survived. We call this survival tactic the distant observer 237 00:11:10.840 --> 00:11:13.919 self explanatory. It was simply too far away to be 238 00:11:14.000 --> 00:11:16.799 touched by the Red Giant's expansion. The star swelled up, 239 00:11:16.919 --> 00:11:18.960 but the planet was sitting way back in the cheap 240 00:11:18.960 --> 00:11:21.679 seats watching the fireworks, completely safe. 241 00:11:21.759 --> 00:11:25.879 So the strategy there is simple avoidance. Just be really 242 00:11:25.919 --> 00:11:26.679 really far away. 243 00:11:26.799 --> 00:11:30.000 Exactly. It's the safest bet. If you aren't near the explosion, 244 00:11:30.120 --> 00:11:31.960 you don't get hurt. Problem solved. 245 00:11:32.399 --> 00:11:35.159 But then in twenty twenty we got a second clue 246 00:11:35.159 --> 00:11:36.759 that really complicated the picture. 247 00:11:37.200 --> 00:11:41.159 The plot thickens because nature is never that simple. 248 00:11:41.360 --> 00:11:43.440 Never what happened in twenty twenty. 249 00:11:43.320 --> 00:11:47.639 Astronomers found another Jupiter sized gas giant around a white dwarf. 250 00:11:47.960 --> 00:11:50.360 But this one was orbiting very close to the star. 251 00:11:50.759 --> 00:11:51.600 How close are we talking? 252 00:11:51.759 --> 00:11:53.559 Close enough that it completes an orbit in just a 253 00:11:53.600 --> 00:11:56.279 few days, not years. It was hugging the star well 254 00:11:56.440 --> 00:11:59.480 well within where Mercury's orbit would be in our Solar system. 255 00:11:59.519 --> 00:12:02.120 Wait, hang on, if it's that close, it should have 256 00:12:02.120 --> 00:12:04.399 been eaten. We just established that when the star was 257 00:12:04.440 --> 00:12:07.159 a red giant, it would have expanded way past that orbit, 258 00:12:07.320 --> 00:12:11.200 way past it should be inside the star's stomach, effectively exactly. 259 00:12:11.399 --> 00:12:14.240 That is the puzzle. It could not have survived the 260 00:12:14.279 --> 00:12:17.000 red giant phase at its current distance. It would have 261 00:12:17.039 --> 00:12:21.519 been engulfed and destroyed instantly, no question. So how is 262 00:12:21.559 --> 00:12:25.759 it there? Is it a ghost planet? Did it form afterwards? 263 00:12:26.279 --> 00:12:27.879 Like a phoenix rising from the ashes? 264 00:12:28.039 --> 00:12:31.919 Unlikely to form afterwards? There isn't usually enough material left 265 00:12:31.919 --> 00:12:35.000 in the disk around a white dwarf to build a giant. 266 00:12:34.720 --> 00:12:36.840 Planet from scratch, it was the theory. 267 00:12:36.919 --> 00:12:39.480 The leading theory is that this planet is the migrator. 268 00:12:39.600 --> 00:12:42.639 It didn't start there. It survived the red giant phase 269 00:12:42.679 --> 00:12:44.840 by being further out, maybe in that safe zone we 270 00:12:44.840 --> 00:12:46.919 talked about beyond a few au Okay. 271 00:12:46.720 --> 00:12:48.440 So as a distant observer at first. 272 00:12:48.200 --> 00:12:51.159 Yes, But then after the star shrank down into a 273 00:12:51.159 --> 00:12:54.639 white dwarf and things calmed down, something caused the planet 274 00:12:54.679 --> 00:12:55.679 to spiral inward. 275 00:12:55.960 --> 00:12:58.159 So it moved into the empty house after the fire 276 00:12:58.279 --> 00:12:58.720 was put out. 277 00:12:58.759 --> 00:13:00.600 That's a great way to put it. It survived the 278 00:13:00.679 --> 00:13:04.759 danger zone, then migrated in later. Usually this happens because 279 00:13:04.799 --> 00:13:07.720 of scattering. Maybe another massive planet in the system gave 280 00:13:07.759 --> 00:13:10.720 it a gravitational kick, or the disc of debris left 281 00:13:10.759 --> 00:13:12.559 over from the star's death dragged it in. 282 00:13:12.840 --> 00:13:16.519 So we have two pathways to survival. Pathway one the 283 00:13:16.559 --> 00:13:20.159 distant observer stay far away and don't move. Pathway two 284 00:13:20.559 --> 00:13:23.799 the migrator stay far away during the danger, then move 285 00:13:23.840 --> 00:13:25.000 in close when it's safe. 286 00:13:25.240 --> 00:13:27.039 Those seem to be the two main options. If you 287 00:13:27.039 --> 00:13:29.000 stay close and don't move, you die. 288 00:13:29.159 --> 00:13:33.080 Simple rules for a complicated universe. But here's the problem, 289 00:13:33.279 --> 00:13:35.360 and this leads us right into the new research from 290 00:13:35.399 --> 00:13:39.279 Max Soriano. We found these two examples, right, A couple 291 00:13:39.320 --> 00:13:41.480 others maybe, but we haven't found many. 292 00:13:41.639 --> 00:13:44.840 That is the issue. We have found thousands of exoplanets 293 00:13:44.879 --> 00:13:48.240 around normal stars, thousands, we find them everywhere we look. 294 00:13:48.840 --> 00:13:52.159 But planets around white dwarfs we have a literal handful. 295 00:13:52.519 --> 00:13:55.360 So the question is are they missing because they are rare, 296 00:13:56.279 --> 00:13:58.039 or are they missing because we just aren't good at 297 00:13:58.080 --> 00:13:58.559 seeing them. 298 00:13:58.679 --> 00:14:02.240 This is the classic servational bias problem in astronomy. It's 299 00:14:02.279 --> 00:14:03.159 a huge question. 300 00:14:03.360 --> 00:14:05.480 Maybe they're there, but we just can't spot them. 301 00:14:05.720 --> 00:14:09.960 It's possible white dorks are dim. Planets are dim. Maybe 302 00:14:09.960 --> 00:14:12.200 the glare from the white dwarf, even though it's faint, 303 00:14:12.399 --> 00:14:15.080 hides them. Maybe we just haven't looked at enough of 304 00:14:15.120 --> 00:14:17.600 them for long enough. It's like looking for a needle 305 00:14:17.600 --> 00:14:19.440 in a haystack, but we aren't sure if we're even 306 00:14:19.480 --> 00:14:20.360 holding a magnet. 307 00:14:20.600 --> 00:14:22.679 And this is where Max Soriano and the team from 308 00:14:22.759 --> 00:14:27.639 Chili come in. They decided to stop guessing and start simulating. 309 00:14:27.919 --> 00:14:31.080 Right. Instead of just relying on our limited telescope data, 310 00:14:31.200 --> 00:14:35.759 they used stellar evolution codes. They essentially built a physics 311 00:14:35.799 --> 00:14:37.080 engine of the Milky Way. 312 00:14:37.159 --> 00:14:39.159 I love when scientists do this. We can't find it, 313 00:14:39.200 --> 00:14:41.799 so let's build a universe where we can calculate it. 314 00:14:41.799 --> 00:14:44.320 It's like playing some city, but with solar systems. 315 00:14:44.399 --> 00:14:48.639 It's an incredibly powerful tool. They factored in everything mass 316 00:14:48.639 --> 00:14:52.159 loss from the star, how gravity changes, the tidal forces, 317 00:14:52.159 --> 00:14:55.279 which we'll get to, the metallic makeup of stars. They 318 00:14:55.360 --> 00:14:58.039 ran the numbers to predict how many of these survivors 319 00:14:58.039 --> 00:14:59.000 should exist. 320 00:14:58.759 --> 00:15:01.399 So they're not observing, therefore casting exactly. 321 00:15:01.639 --> 00:15:05.039 They simulated the entire life cycle from birth to death 322 00:15:05.360 --> 00:15:07.679 for millions of scenarios to see what the end result 323 00:15:07.720 --> 00:15:09.360 should be, and they. 324 00:15:09.200 --> 00:15:12.440 Came back with a number, a specific percentage of white 325 00:15:12.480 --> 00:15:15.559 dwarfs that should have a Jupiter like survivor orbiting them. 326 00:15:15.600 --> 00:15:18.720 They did, and that number is less than three percent. 327 00:15:18.879 --> 00:15:21.879 Wow, less than three percent. Yes, that means for every 328 00:15:21.919 --> 00:15:25.240 one hundred dead stars you look at, ninety seven of 329 00:15:25.279 --> 00:15:27.559 them are alone or at least they don't have a 330 00:15:27.720 --> 00:15:28.919 gas giant survivor. 331 00:15:29.000 --> 00:15:32.120 It is a massacre out there. The vast, vast majority 332 00:15:32.159 --> 00:15:33.320 of planets do not make it. 333 00:15:33.480 --> 00:15:35.279 That feels incredibly low. I mean, we look at our 334 00:15:35.279 --> 00:15:37.480 Solar System. We see Jupiter and Saturna. They seem so 335 00:15:37.519 --> 00:15:39.639 big and permanent. We think of them as the kings 336 00:15:39.639 --> 00:15:43.320 of the Solar System. We assume they are invincible. But 337 00:15:43.399 --> 00:15:46.919 you're saying, in the grand scheme of stellar evolution, keeping 338 00:15:46.960 --> 00:15:48.559 a planet like that is a rarity. 339 00:15:48.879 --> 00:15:52.639 It is. The transition to a white dwarf is a chaotic, 340 00:15:52.840 --> 00:15:56.519 violent event. It cleans house. Now there is a small 341 00:15:56.559 --> 00:15:59.200 caveat the researchers point out, which is important. If we 342 00:15:59.240 --> 00:16:02.200 look at what they call the local age metallicity relation, 343 00:16:02.600 --> 00:16:05.440 basically stars that are similar to our Sun and in 344 00:16:05.480 --> 00:16:08.159 our local neighborhood of the galaxy, that number might creep 345 00:16:08.240 --> 00:16:09.399 up to roughly eight percent. 346 00:16:09.639 --> 00:16:12.360 Okay, eight percent is better than three percent, but it's 347 00:16:12.399 --> 00:16:14.679 still single digits. It's still a tiny minority. 348 00:16:14.799 --> 00:16:17.759 Absolutely. It implies that a white dwarf with a planet 349 00:16:17.879 --> 00:16:20.759 is the exception, not the rule. The default state for 350 00:16:20.799 --> 00:16:22.759 a dead star is loneliness. 351 00:16:23.080 --> 00:16:25.919 And another thing that study noted, ninety five percent of 352 00:16:25.960 --> 00:16:30.080 these survivors are gas giants like Jupiter, not brown dwarfs. 353 00:16:30.399 --> 00:16:34.840 That's an important distinction. Brown dwarfs are these failed stars. 354 00:16:35.360 --> 00:16:38.480 They are heavier than planets anywhere from thirteen to eighty 355 00:16:38.559 --> 00:16:41.480 times the mass of Jupiter, but not heavy enough to 356 00:16:41.519 --> 00:16:43.120 ignite fusion in their cores. 357 00:16:43.360 --> 00:16:45.960 You would think being heavier and tougher they would survive better. 358 00:16:46.120 --> 00:16:48.759 Yeah, logic would suggest the biggest kid on the playground 359 00:16:48.759 --> 00:16:50.879 doesn't get pushed around. If you're heavier, you should be 360 00:16:50.919 --> 00:16:53.759 harder to push into the star. Right, more inertia, you'd think, 361 00:16:54.360 --> 00:16:56.919 But the simulation shows that planets seem to survive better 362 00:16:56.960 --> 00:16:59.919 than brown dwarfs in this specific context. It's a nuanced 363 00:17:00.039 --> 00:17:01.440 interplay of a few things. 364 00:17:01.360 --> 00:17:02.120 Like what well. 365 00:17:02.159 --> 00:17:04.599 First, Brown corps are rare to begin with compared to 366 00:17:04.640 --> 00:17:08.519 gas giants, but more importantly, they interact with tides differently. 367 00:17:08.960 --> 00:17:11.640 They raise much stronger tides on the star because they. 368 00:17:11.519 --> 00:17:14.680 Are so massive ah, and stronger tides create more. 369 00:17:14.640 --> 00:17:19.039 Drag exactly, more drag which pulls them in faster. So 370 00:17:19.119 --> 00:17:21.599 being big can actually be a disadvantage here. You're too 371 00:17:21.640 --> 00:17:24.319 good at slowing yourself down and spiraling to your doom. 372 00:17:24.440 --> 00:17:26.759 So if you want to survive the apocalypse, be a 373 00:17:26.799 --> 00:17:30.400 gas giant, don't be a brown dwarf, and definitely don't 374 00:17:30.400 --> 00:17:31.920 be a rocky planet like Earth. 375 00:17:32.119 --> 00:17:35.559 Correct, Rocky planets are usually too close, they get swallowed. 376 00:17:35.920 --> 00:17:38.240 Being small and close is a death sentence. 377 00:17:39.240 --> 00:17:41.279 Okay, so we know it's rare, we know it's dangerous. 378 00:17:41.640 --> 00:17:45.119 But let's dig into the survivor's handbook. Because even though 379 00:17:45.160 --> 00:17:48.119 only three percent make it, some do make it. Who 380 00:17:48.160 --> 00:17:50.720 are they? What makes them special? The paper breaks this 381 00:17:50.799 --> 00:17:53.000 down into specific factors they did. 382 00:17:53.440 --> 00:17:56.400 They identified several key factors. Think of this as the 383 00:17:56.480 --> 00:17:58.839 checklist for survival. If you are a planet and you 384 00:17:58.880 --> 00:18:01.079 want to live, you need to check these boxes. 385 00:18:01.119 --> 00:18:03.279 Factor're number one, the parent stars mass. 386 00:18:03.480 --> 00:18:06.279 This is crucial. It turns out there's a Goldilock zone 387 00:18:06.279 --> 00:18:08.759 for the star itself. Not too hot, not too cold, 388 00:18:08.920 --> 00:18:10.160 not too big, not too small. 389 00:18:10.240 --> 00:18:10.559 Okay. 390 00:18:10.640 --> 00:18:13.440 Survival peaks when the resulting white dwarf ends up being 391 00:18:13.480 --> 00:18:16.599 between point five to three and point sixty six solar masses. 392 00:18:16.839 --> 00:18:20.279 Okay, those are numbers. Translate that. What does that mean 393 00:18:20.319 --> 00:18:22.799 for the star before it died, when it was in 394 00:18:22.839 --> 00:18:23.359 its prime. 395 00:18:23.599 --> 00:18:27.200 It corresponds to a progenitor, the original star having a 396 00:18:27.240 --> 00:18:29.319 mass of about one to three times the mass of 397 00:18:29.319 --> 00:18:29.720 our sun. 398 00:18:29.920 --> 00:18:31.920 So you don't want a star that was too huge 399 00:18:31.920 --> 00:18:32.839 to begin with, right. 400 00:18:33.079 --> 00:18:36.200 If the star is really massive, say eight or ten 401 00:18:36.319 --> 00:18:39.400