WEBVTT 1 00:00:03.439 --> 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 --> 00:00:26.879 slumber under the night sky. 7 00:00:27.039 --> 00:00:32.240 So I want you to imagine stepping outside tomorrow morning. 8 00:00:32.399 --> 00:00:33.640 You know you've got your coffee in hand. 9 00:00:33.719 --> 00:00:34.479 That's time of the day. 10 00:00:34.520 --> 00:00:37.200 Oh absolutely, So you walk out onto your porch, you 11 00:00:37.240 --> 00:00:40.359 look up at the morning sky, and instead of our 12 00:00:40.439 --> 00:00:43.240 single familiar yellow sugn just kind of rising in the east, right, 13 00:00:43.640 --> 00:00:48.679 you see five massive burning spheres of plasma just right 14 00:00:48.679 --> 00:00:49.399 there in the sky. 15 00:00:49.719 --> 00:00:52.880 That would definitely wake you up faster than the coffee. 16 00:00:52.960 --> 00:00:55.920 Right. I mean, they'd be casting these multiple overlapping shadows 17 00:00:55.920 --> 00:00:59.000 on your lawn. You'd have different hues of orange and 18 00:00:59.119 --> 00:01:02.159 red and this stark, blinding white. 19 00:01:02.200 --> 00:01:05.799 It sounds like a backdrop for a massive space opera. 20 00:01:05.599 --> 00:01:07.680 Or something exactly like something cooked up into sci fi 21 00:01:07.719 --> 00:01:10.319 writer's room. But the crazy thing is in our immediate 22 00:01:10.359 --> 00:01:13.560 cosmic neighborhood. This is actually an absolute, ongoing reality. 23 00:01:13.719 --> 00:01:15.840 Yeah, it really is. And I think you know our 24 00:01:15.959 --> 00:01:18.799 daily experience waking up to just one sun that makes 25 00:01:18.799 --> 00:01:23.640 its journey across the sky completely alone. It creates this massive, 26 00:01:23.799 --> 00:01:27.159 ingrained psychological bias for us. We just naturally assume the 27 00:01:27.200 --> 00:01:31.200 rest of the universe operates on this exact same single 28 00:01:31.239 --> 00:01:33.000 sun blueprint, because. 29 00:01:32.760 --> 00:01:36.040 That's all we know. But being a single star like 30 00:01:36.120 --> 00:01:40.159 our sun actually makes us the absolute weirdos of the galaxy, 31 00:01:40.200 --> 00:01:40.560 doesn't it. 32 00:01:40.799 --> 00:01:42.719 We really are the odd ones out. I mean that 33 00:01:42.879 --> 00:01:47.079 human experience is just incredibly localized. We project our solar 34 00:01:47.079 --> 00:01:51.040 system's orderly, single anchor structure onto the rest of the. 35 00:01:50.959 --> 00:01:53.760 Cosmos, which makes sense logically, sure it does. 36 00:01:54.079 --> 00:01:56.719 But the sheer volume of stars out there that are 37 00:01:56.799 --> 00:02:01.920 actively bound up in these complex gravitational relationships with other stars, 38 00:02:02.280 --> 00:02:03.000 it's staggering. 39 00:02:03.079 --> 00:02:04.560 It's a crowded universe out there. 40 00:02:04.439 --> 00:02:07.359 Oh, Incredibly, the universe is a far more dynamic and 41 00:02:07.480 --> 00:02:11.199 chaotic and just crowded environment than a casual glance at 42 00:02:11.199 --> 00:02:13.080 our night sky would ever lead you to believe. 43 00:02:13.719 --> 00:02:17.360 So today our mission is to basically dismantle that bias completely. 44 00:02:17.639 --> 00:02:20.560 We're going to map out the precise relationship statuses of 45 00:02:20.599 --> 00:02:21.960 the star's closest. 46 00:02:21.560 --> 00:02:24.120 To us, which is such a fascinating project, it really is. 47 00:02:24.360 --> 00:02:27.719 Astronomers the University Madrid have just completed this incredible, definitive 48 00:02:27.759 --> 00:02:31.759 census of our local cosmic neighborhood and they're combining you know, 49 00:02:31.800 --> 00:02:35.199 modern space telescope data with century old catalogs. 50 00:02:34.960 --> 00:02:38.360 And we are going to explore exactly who is paired up, 51 00:02:38.479 --> 00:02:44.280 who is flying solo and why. Untangling these incredibly complex 52 00:02:44.479 --> 00:02:47.520 stellar relationships is so important. 53 00:02:47.280 --> 00:02:50.599 Right because it's essentially the ultimate prerequisite for one of 54 00:02:50.680 --> 00:02:54.319 the greatest quests in human history, which is finding a. 55 00:02:54.280 --> 00:02:56.919 Second Earth exactly. I mean, if the ultimate goal is 56 00:02:56.960 --> 00:03:00.319 to find habitable planets, you know, worlds where liquid water 57 00:03:00.319 --> 00:03:03.479 could exist and life might thrive, we first have to 58 00:03:03.479 --> 00:03:06.360 thoroughly understand the stars those planets might be orbiting. 59 00:03:06.599 --> 00:03:08.759 You can't just blindly point a telescope and hope for 60 00:03:08.759 --> 00:03:09.080 the best. 61 00:03:09.159 --> 00:03:10.879 No, you really can't. The only way to build that 62 00:03:11.000 --> 00:03:13.520 understanding is to know exactly what is happening in our 63 00:03:13.560 --> 00:03:16.719 own backyard. We cannot filter the noise of the deep 64 00:03:16.840 --> 00:03:19.120 universe if we do not even know who is living 65 00:03:19.159 --> 00:03:19.639 next door. 66 00:03:20.000 --> 00:03:22.840 Okay, so let's start by defining that backyard. Yeah, because 67 00:03:22.840 --> 00:03:25.080 we need a boundary, right, We can't just say nearby. 68 00:03:25.520 --> 00:03:28.120 In astronomy, nearby could mean a million light years. 69 00:03:28.199 --> 00:03:31.840 Yeah, exactly. So the astronomers compiling this definitive map, they 70 00:03:31.879 --> 00:03:35.840 do this highly specific mathematical bubble around our solar system. 71 00:03:36.400 --> 00:03:39.759 The boundary is set at exactly ten parsecs away. 72 00:03:39.520 --> 00:03:42.800 From the Sun, extending in every single direction to form 73 00:03:42.840 --> 00:03:43.960 a perfect sphere. 74 00:03:44.240 --> 00:03:46.759 Right, and for anyone doing the cosmic math at home, 75 00:03:47.319 --> 00:03:52.879 ten parsecs translates to thirty two point six light years. 76 00:03:52.639 --> 00:03:54.560 Which is a very specific number. 77 00:03:54.759 --> 00:03:58.560 It is, and inside this specific ten carsec bubble there 78 00:03:58.599 --> 00:04:03.560 are exactly four hundred twenty four known stellar and substellar objects. 79 00:04:03.919 --> 00:04:06.400 But I mean thirty two point six light years feels 80 00:04:06.719 --> 00:04:07.879 strangely arbitrary. 81 00:04:08.000 --> 00:04:09.800 It does sound random at first. 82 00:04:09.560 --> 00:04:12.000 Yeah, because the Milky Way Galaxy is over one hundred 83 00:04:12.000 --> 00:04:14.840 thousand light years across. So why draw the lines so 84 00:04:14.919 --> 00:04:16.639 close to home? Why ten parsecs? 85 00:04:16.759 --> 00:04:19.279 Well, it all comes down to this foundational concept in 86 00:04:19.360 --> 00:04:21.759 observational astronomy, which is completeness. 87 00:04:21.959 --> 00:04:24.160 Completeness meaning we know everything that's. 88 00:04:23.959 --> 00:04:27.480 In there exactly. The primary enemy of any astronomical survey 89 00:04:27.560 --> 00:04:30.399 is distance. The further out into the galaxy you look, 90 00:04:30.439 --> 00:04:33.680 the harder it becomes to visually resolve the fine details 91 00:04:33.720 --> 00:04:35.000 of a star system. 92 00:04:34.759 --> 00:04:36.600 Like trying to see the details of a car from 93 00:04:36.639 --> 00:04:37.480 ten miles away. 94 00:04:37.519 --> 00:04:41.040 Precisely, it becomes intensely mathematically difficult to see whether a 95 00:04:41.079 --> 00:04:43.279 star has a companion hidden right next to it, because 96 00:04:43.279 --> 00:04:45.439 it just gets lost in the blinding glare of the 97 00:04:45.480 --> 00:04:46.279 primary star. 98 00:04:46.639 --> 00:04:48.879 You know, I was thinking about this like a neighborhood 99 00:04:48.879 --> 00:04:49.680 watch program. 100 00:04:49.959 --> 00:04:50.839 Oh I like that? 101 00:04:51.120 --> 00:04:55.439 How so well, it's incredibly easy to know exactly who 102 00:04:55.439 --> 00:04:58.000 lives on your own street. Right, you see your neighbors 103 00:04:58.040 --> 00:05:01.439 taking out the trash, You recognize their You know exactly 104 00:05:01.480 --> 00:05:03.639 who lives in which house. Sure, you might even have 105 00:05:03.680 --> 00:05:06.199 a pretty good read on the street behind yours, But 106 00:05:06.360 --> 00:05:09.519 if you try to figure out who is permanently crashing 107 00:05:09.560 --> 00:05:12.600 on the couch of a house like three towns away. 108 00:05:12.560 --> 00:05:14.839 You wouldn't have a clue exactly. 109 00:05:14.560 --> 00:05:17.879 From where you're standing. It is completely impossible. You just 110 00:05:18.000 --> 00:05:21.199 cannot see through the structural noise of the intervening houses 111 00:05:21.480 --> 00:05:23.040 and the distance to know for sure. 112 00:05:23.319 --> 00:05:27.519 That captures the structural problem perfectly, expanding the bubble to 113 00:05:27.920 --> 00:05:31.680 say fifty or one hundred parsecs would introduce a massive 114 00:05:31.680 --> 00:05:33.199 amount of uncertainty into the data. 115 00:05:33.399 --> 00:05:35.959 We just start missing the cosmic couch surfers. 116 00:05:35.720 --> 00:05:39.040 Exactly, We would start missing things. By strictly limiting the 117 00:05:39.079 --> 00:05:43.959 boundary to exactly ten parsecs, astronomers can mathematically lower the 118 00:05:43.959 --> 00:05:46.879 probability of missing those starry companions that are hiding in 119 00:05:46.920 --> 00:05:47.399 the wings. 120 00:05:47.480 --> 00:05:50.279 So it's about confidence in the data, oh, one hundred percent. 121 00:05:51.120 --> 00:05:55.120 This constraint allows for a very high degree of statistical 122 00:05:55.160 --> 00:05:58.959 confidence the map is considered complete. We know we haven't 123 00:05:58.959 --> 00:05:59.959 missed any hidden roommate. 124 00:06:00.160 --> 00:06:03.160 Okay, but wait, that still doesn't quite add up for me. 125 00:06:03.560 --> 00:06:04.600 Oh why not? 126 00:06:04.879 --> 00:06:08.040 Because we currently have telescopes operating in space that are 127 00:06:08.079 --> 00:06:13.279 sending back crystal clear, high definition images of galaxies that 128 00:06:13.360 --> 00:06:15.240 are billions of late years away. 129 00:06:15.360 --> 00:06:17.800 Oh right, like James Webb and Hubble. 130 00:06:18.040 --> 00:06:21.079 Yeah, we are literally looking back in time to the 131 00:06:21.120 --> 00:06:24.000 dawn of the universe. So if the optics exist to 132 00:06:24.079 --> 00:06:26.839 capture a galaxy on the edge of the observable universe, 133 00:06:27.240 --> 00:06:30.560 why is it mechanically so difficult to spot a single 134 00:06:30.600 --> 00:06:34.000 companion star that is just say, fifteen parsex down the 135 00:06:34.000 --> 00:06:36.560 cosmic street. That's a really great point right, Why does 136 00:06:36.600 --> 00:06:38.959 the physics fall apart at such a relatively short distance. 137 00:06:39.040 --> 00:06:42.639 Well, the distinction lies in what those telescopes are actually resolving. 138 00:06:42.879 --> 00:06:45.639 When you look at a galaxy billions of late years away, 139 00:06:45.720 --> 00:06:47.519 you are not resolving individual stars. 140 00:06:47.639 --> 00:06:48.920 You're just seeing the whole thing at once. 141 00:06:49.199 --> 00:06:53.920 Exactly, you are observing the combined massive glow of hundreds 142 00:06:53.920 --> 00:06:58.480 of billions of stars spread out over an unfathomably huge area. 143 00:06:58.600 --> 00:06:59.839 It's a massive smear of light. 144 00:07:00.199 --> 00:07:00.319 Ok. 145 00:07:00.600 --> 00:07:03.720 When you look at a star system just fifteen parsecs away, 146 00:07:04.360 --> 00:07:08.160 you are trying to resolve a tiny, specific point source 147 00:07:08.160 --> 00:07:08.519 of light. 148 00:07:08.800 --> 00:07:11.839 You are looking for a single microscopic. 149 00:07:11.160 --> 00:07:15.160 Dot, and that dot is unimaginably bright. I mean, stars 150 00:07:15.199 --> 00:07:19.800 are colossal nuclear fusion engines. They create a blinding amount 151 00:07:19.800 --> 00:07:20.600 of glare. 152 00:07:20.360 --> 00:07:22.399 Right, They are just reflecting light, They're making. 153 00:07:22.199 --> 00:07:25.319 It exactly so. If a companion star is orbiting relatively 154 00:07:25.399 --> 00:07:28.079 close to a primary star, the light from the primary 155 00:07:28.199 --> 00:07:30.680 completely washes out the dimmer companion. 156 00:07:31.040 --> 00:07:31.720 Ah. I see. 157 00:07:31.759 --> 00:07:34.279 Think of it like trying to spot a firefly hovering 158 00:07:34.360 --> 00:07:37.360 three inches away from a stadium floodlight while you are 159 00:07:37.399 --> 00:07:38.639 standing two miles down the road. 160 00:07:38.720 --> 00:07:41.240 Oh wow, Yeah, the sheer volume of photons from the 161 00:07:41.279 --> 00:07:45.079 floodlight would just utterly destroy your ability to perceive the 162 00:07:45.079 --> 00:07:46.160 firefly exactly. 163 00:07:46.199 --> 00:07:49.000 The firefly is completely swallowed by the visual noise. 164 00:07:49.079 --> 00:07:51.480 So it's not a distance problem, it's a glare problem. 165 00:07:51.639 --> 00:07:56.399 Precisely. This limitation is governed by something called angular resolution. 166 00:07:57.439 --> 00:08:01.800 No matter how perfectly polished your telescope mirror is or 167 00:08:02.000 --> 00:08:05.959 how advanced your sensors are, light ultimately behaves as a wave. 168 00:08:06.279 --> 00:08:07.639 Right, So when light. 169 00:08:07.480 --> 00:08:10.480 Waves past the edges of a telescope's aperture, they bend 170 00:08:10.560 --> 00:08:14.560 and spread out. This is a phenomenon called diffraction diffraction, okay, 171 00:08:14.560 --> 00:08:17.600 And this creates a tiny blur around every point of 172 00:08:17.680 --> 00:08:20.800 light on the sensor. If two stars are too close 173 00:08:20.839 --> 00:08:23.199 together in the sky, their diffraction blurs. 174 00:08:22.959 --> 00:08:25.480 Overlap and they just merge into a single blob of 175 00:08:25.560 --> 00:08:26.439 light exactly. 176 00:08:26.680 --> 00:08:29.759 Keeping the sensus tightly constrained to ten parsecs means the 177 00:08:29.800 --> 00:08:33.200 physical distance between the stars translates to a wide enough 178 00:08:33.240 --> 00:08:36.039 angle in our sky. It ensures the floodlight and the 179 00:08:36.080 --> 00:08:39.320 firefly appear far enough apart that our instruments can reliably 180 00:08:39.360 --> 00:08:39.919 separate them. 181 00:08:40.000 --> 00:08:42.879 Okay, that makes that urbitrainer would make total sense. It's 182 00:08:42.919 --> 00:08:45.639 literally the physical limit of knowing our data is pure 183 00:08:45.840 --> 00:08:49.240 exactly now, compiling a flawless map of four hundred and 184 00:08:49.279 --> 00:08:51.960 twenty four objects isn't something you do by just pointing 185 00:08:52.000 --> 00:08:54.320 a backyard telescope at the sky and taking notes, right, 186 00:08:54.399 --> 00:08:57.600 Definitely not the data required to prove these objects exist, 187 00:08:57.919 --> 00:09:00.960 and more importantly, to prove they are at interacting with 188 00:09:01.000 --> 00:09:03.080 each other. That must be monumental. 189 00:09:03.159 --> 00:09:06.519 Oh, it's staggering. The Census is the culmination of combining 190 00:09:06.559 --> 00:09:10.279 two of the most sophisticated massive data sets ever compiled 191 00:09:10.320 --> 00:09:11.039 by humanity. 192 00:09:11.159 --> 00:09:12.120 Wow, what are they? 193 00:09:12.480 --> 00:09:15.080 The structural backbone of this map comes from the d 194 00:09:15.279 --> 00:09:19.240 R three data release from the European Space Agency's Gaya telescope. 195 00:09:19.360 --> 00:09:20.799 Gaya, I've heard of that one. 196 00:09:20.840 --> 00:09:23.639 It's an incredible piece of technology. Gaya is a space 197 00:09:23.679 --> 00:09:27.440 observatory specifically designed for astrometry. 198 00:09:27.919 --> 00:09:31.519 That's the precise measurement of where things. 199 00:09:31.360 --> 00:09:36.279 Are, vacation distance, and motion exactly. Gaya is essentially building 200 00:09:36.360 --> 00:09:40.000 a highly dynamic, three dimensional map of the entire Milky 201 00:09:40.000 --> 00:09:40.639 Way Galaxy. 202 00:09:40.720 --> 00:09:43.039 That's ambitious, very. 203 00:09:42.519 --> 00:09:45.320 It measures the positions of over a billion stars with 204 00:09:45.399 --> 00:09:48.320 a level of precision that is honestly difficult to overstate. 205 00:09:48.840 --> 00:09:50.960 It can measure the width of a human hair from 206 00:09:51.080 --> 00:09:52.200 hundreds of miles away. 207 00:09:52.320 --> 00:09:54.080 Seriously, that is insane. 208 00:09:54.159 --> 00:09:58.600 It's phenomenal engineering. But positional data is really only half 209 00:09:58.639 --> 00:09:59.519 the puzzle. 210 00:09:59.480 --> 00:10:01.639 Right, because just knowing where two stars are it doesn't 211 00:10:01.679 --> 00:10:03.320 mean they are interacting exactly. 212 00:10:03.399 --> 00:10:06.000 To know if stars are actually in a relationship, you 213 00:10:06.080 --> 00:10:09.080 need movement over time. That is where the researcher is 214 00:10:09.080 --> 00:10:11.200 brought in the Washington Double Star Catalog. 215 00:10:11.639 --> 00:10:13.759 Now, I was looking at the history of the Washington 216 00:10:13.799 --> 00:10:17.840 Double Star Catalog. It is fascinating because it isn't just 217 00:10:17.960 --> 00:10:23.240 a modern digital list. It represents decades, even centuries of 218 00:10:23.360 --> 00:10:24.120 human observation. 219 00:10:24.240 --> 00:10:27.320 It really is a historical treasure. It's the world's principal 220 00:10:27.399 --> 00:10:31.720 database of visual double stars. It actually contains historical observations 221 00:10:31.799 --> 00:10:33.919 dating all the way back to the nineteenth century. 222 00:10:33.960 --> 00:10:37.399 Wow, so people with early telescopes sketching things out basically. 223 00:10:37.519 --> 00:10:41.120 Yeah, And that historical data is combined with decades of 224 00:10:41.240 --> 00:10:43.240 modern radial velocity measurements. 225 00:10:43.519 --> 00:10:46.320 Radio velocity being how fast a star is moving along 226 00:10:46.360 --> 00:10:48.600 our line of sight, like either toward us or away 227 00:10:48.600 --> 00:10:48.879 from us. 228 00:10:48.960 --> 00:10:53.360 You've got it perfectly by fusing Guya's ultra precise three 229 00:10:53.440 --> 00:10:56.440 D positioning. With the deep historical motion data from the 230 00:10:56.519 --> 00:11:00.679 Washington Catalog, astronomers could trace the exact trey objectories of 231 00:11:00.720 --> 00:11:02.080 these objects over time, so. 232 00:11:02.039 --> 00:11:03.320 They can see the actual dance. 233 00:11:03.559 --> 00:11:07.159 Yes, they could definitively prove which stars were locked in 234 00:11:07.200 --> 00:11:10.840 a gravitational embrace and which were just optical illusions. 235 00:11:10.919 --> 00:11:13.879 Optical illusions like stars that look close together from Earth 236 00:11:14.120 --> 00:11:17.399 but are actually separated by vast distances in deep space. 237 00:11:17.600 --> 00:11:20.440 Exactly we call those optical binaries. They just happen to 238 00:11:20.480 --> 00:11:22.799 line up perfectly from our vantage point, but they have 239 00:11:22.879 --> 00:11:23.919 nothing to do with each other. 240 00:11:24.159 --> 00:11:27.440 Okay, so the ten Parsak bubble is set, the pristine 241 00:11:27.519 --> 00:11:30.679 data is gathered, and all the false positives those optical 242 00:11:30.759 --> 00:11:35.360 illusions are filtered out. Let's dig into the actual census results. 243 00:11:35.440 --> 00:11:37.840 Let's do it. Who is actually paired up in our neighborhood. 244 00:11:38.039 --> 00:11:40.240 Out of the four hundred and twenty four objects inside 245 00:11:40.279 --> 00:11:43.200 this bubble, two hundred and fifteen of them are bound 246 00:11:43.279 --> 00:11:45.840 up in multiple star systems, which means over half the 247 00:11:45.840 --> 00:11:48.679 population is coupled up. Literally, more than half the neighborhood 248 00:11:48.759 --> 00:11:51.360 is in a relationship, and they aren't just in simple pairs. Either. 249 00:11:51.480 --> 00:11:52.879 No, it gets much more complicated. 250 00:11:53.159 --> 00:11:56.320 These two hundred and fifteen objects are distributed across ninety 251 00:11:56.320 --> 00:12:00.559 two distinct multiple star systems, and the structural breakdown of 252 00:12:00.600 --> 00:12:02.600 these systems is shockingly diverse. 253 00:12:02.759 --> 00:12:04.080 It really runs the gamut. 254 00:12:04.399 --> 00:12:07.240 Right, So there are sixty eight classic double star systems, 255 00:12:07.320 --> 00:12:12.320 you know, binaries. But then there are nineteen triple star systems. 256 00:12:11.919 --> 00:12:13.480 Three stars all dancing together. 257 00:12:13.600 --> 00:12:17.240 Yeah. And then there are three quadruple systems, and perhaps 258 00:12:17.279 --> 00:12:20.159 the most mind bending of all, there are two incredibly 259 00:12:20.279 --> 00:12:24.639 rare kintuple star systems. Five star, five separate stars, all 260 00:12:24.679 --> 00:12:28.919 gravitationally bound to each other, existing is a single cohesive unit. 261 00:12:29.120 --> 00:12:32.720 You know. Visualizing a system with five massive bodies of 262 00:12:32.759 --> 00:12:36.840 burning plasma is challenging because our brains just naturally default 263 00:12:36.840 --> 00:12:38.480 to our own solar system model. 264 00:12:38.720 --> 00:12:41.120 Right. I was reading about the structural dynamics of these 265 00:12:41.200 --> 00:12:43.519 quintuple systems and my mind went straight to how they 266 00:12:43.519 --> 00:12:45.279 even organize themselves without crashing. 267 00:12:45.480 --> 00:12:47.039 It's a delicate balance. 268 00:12:46.799 --> 00:12:49.080 Because you can't just have five stars orbiting a single 269 00:12:49.120 --> 00:12:50.519 point like a cosmic merry ground. 270 00:12:50.600 --> 00:12:50.840 Right. 271 00:12:51.120 --> 00:12:53.960 The n body problem in physics dictates that throwing five 272 00:12:54.039 --> 00:12:57.559 massive objects into a random clump just results in pure. 273 00:12:57.360 --> 00:13:00.000 Chaos, absolute chaos. They would violently fling each other. 274 00:13:00.519 --> 00:13:03.559 Yeah, they completely destabilize the orbits until the system either 275 00:13:03.600 --> 00:13:07.360 collapsed inward on itself or forcefully ejected stars out into 276 00:13:07.360 --> 00:13:07.960 deep space. 277 00:13:08.360 --> 00:13:12.720 Exactly. So, to survive for billions of years, gravity forces 278 00:13:12.759 --> 00:13:16.559 them into highly organized, compartmentalized layers. 279 00:13:16.639 --> 00:13:17.519 What's the term for that. 280 00:13:17.759 --> 00:13:21.039 It's called a hierarchical structure. They do not orbit a 281 00:13:21.080 --> 00:13:24.279 central star. They orbit a shared center of mass, a 282 00:13:24.360 --> 00:13:27.000 shared center, yes, and there's a barry center. And they 283 00:13:27.000 --> 00:13:30.120 do this through nested levels of organization. 284 00:13:30.000 --> 00:13:33.440 Nested levels. You know. It reminds me of the intricate 285 00:13:33.480 --> 00:13:35.639 gears inside of mechanical Swiss watch. 286 00:13:35.759 --> 00:13:38.279 Oh that's a brilliant comparison. 287 00:13:37.720 --> 00:13:40.200 Because you don't have five gears all grinding against the 288 00:13:40.240 --> 00:13:43.960 exact same central axle. You have a massive, slow moving 289 00:13:44.000 --> 00:13:48.519 outer gear, and then nested inside that you have small 290 00:13:48.519 --> 00:13:53.399 assemblies spinning independently, and within those even tighter, faster moving parts. 291 00:13:53.519 --> 00:13:56.960 The watch analogy perfectly captures the mechanics. So in a 292 00:13:57.000 --> 00:13:59.720 quintuple system, you might have two stars in a very 293 00:13:59.840 --> 00:14:02.240 tight binary orbits circling each other. 294 00:14:02.159 --> 00:14:04.360 Rapidly, like the ticking secondhand. 295 00:14:04.120 --> 00:14:07.240 Exactly, then a massive distance away, but still within the 296 00:14:07.279 --> 00:14:09.799 exact same system. You have another tight binary pair. 297 00:14:10.080 --> 00:14:12.039 Okay, two separate pairs, Yes, And those. 298 00:14:11.919 --> 00:14:14.639 Two separate binary pairs will then orbit each other. 299 00:14:14.840 --> 00:14:16.559 Wait, the pairs orbit each other. 300 00:14:16.759 --> 00:14:20.559 Yes, The gravitational center of pair A orbits the gravitational 301 00:14:20.639 --> 00:14:23.440 center of pair B. They treat the other pair almost 302 00:14:23.480 --> 00:14:25.960 as if it were a single extra heavy star. 303 00:14:26.039 --> 00:14:29.919 Orbiting pairs of orbiting pairs. That is dizzying. And the 304 00:14:29.919 --> 00:14:30.440 fifth star. 305 00:14:30.799 --> 00:14:34.320 The fifth star is often situated in an incredibly wide orbit, 306 00:14:34.799 --> 00:14:38.360 just slowly circling the entire inner quadruple structure from a 307 00:14:38.399 --> 00:14:39.639 massive distance. 308 00:14:39.320 --> 00:14:41.000 Like the outer casing of the watch. 309 00:14:40.879 --> 00:14:44.320 Exactly, moving at a glacial pace compared to the rapid 310 00:14:44.360 --> 00:14:47.559 ticking of the inner binaries. And the sheer vastness of 311 00:14:47.679 --> 00:14:51.679 space between these hierarchical levels is actually what preserves. 312 00:14:51.240 --> 00:14:54.360 The system, because they're kept far enough apart to not interfere. 313 00:14:54.559 --> 00:14:57.759 Right, the gravitational forces at play locally within a tight 314 00:14:57.799 --> 00:15:01.000 binary are intense, but because the what X structural level 315 00:15:01.039 --> 00:15:04.960 is located so far away that competing gravitational poll is diluted. 316 00:15:05.039 --> 00:15:09.200 Ah I see, they establish a long term stable resonance Chris. 317 00:15:09.240 --> 00:15:11.759 But Okay, if I am a planet in one of 318 00:15:11.759 --> 00:15:15.600 these quadruple or quintuple systems, what does my existence even 319 00:15:15.679 --> 00:15:19.519 look like with all these competing gravitational wells. Do planets 320 00:15:19.559 --> 00:15:22.519 even survive in these environments? Or are they just shredded 321 00:15:22.519 --> 00:15:23.960 into asteroid belts. 322 00:15:24.200 --> 00:15:27.440 It's a rough neighborhood for a planet. The gravitational environment 323 00:15:27.559 --> 00:15:32.639 is incredibly hostile unless they settle into very specific mathematically 324 00:15:32.799 --> 00:15:36.759 safe zones. Safe zones like where well a planet can 325 00:15:36.799 --> 00:15:40.240 survive if it is in an extremely tight close orbit 326 00:15:40.320 --> 00:15:43.480 around just one of the individual stars. In that scenario, 327 00:15:43.879 --> 00:15:46.960 it effectively ignores the distant pole of the other stars 328 00:15:46.960 --> 00:15:47.519 in the system. 329 00:15:47.639 --> 00:15:50.279 It just hugs its parent star really tightly exactly. 330 00:15:50.559 --> 00:15:53.000 Or on the flip side, a planet can exist in 331 00:15:53.039 --> 00:15:54.360 a circumbinary orbit. 332 00:15:54.480 --> 00:15:56.600 Circumbinary meaning orbiting the whole. 333 00:15:56.399 --> 00:15:59.919 Thing right, orbiting incredibly far away from the entire complex, 334 00:16:00.120 --> 00:16:03.399 treating the inner mess of stars as a single gravitational point. 335 00:16:03.440 --> 00:16:05.559 Okay, so way inside or way outside. 336 00:16:05.159 --> 00:16:07.840 Exactly anything in the middle ground, the spaces between the 337 00:16:07.879 --> 00:16:11.080 interacting stars. That is a dynamically unstable death. 338 00:16:10.919 --> 00:16:12.360 Zone, a death zone. 339 00:16:12.399 --> 00:16:15.240 A planet caught there would eventually be ejected from the 340 00:16:15.240 --> 00:16:19.759 system entirely or pulled into a catastrophic collision course with 341 00:16:19.840 --> 00:16:20.440 a star. 342 00:16:20.519 --> 00:16:23.799 So no middle ground. The mechanics are just awe inspiring. 343 00:16:24.440 --> 00:16:27.759 But you know, beyond just mapping the structures, the Census 344 00:16:27.799 --> 00:16:32.279 revealed this really striking mathematical rule about who actually ends 345 00:16:32.360 --> 00:16:33.919 up in these complex relationships. 346 00:16:34.000 --> 00:16:37.320 Oh, yes, the relationship between mass and multiplicity. 347 00:16:37.600 --> 00:16:41.240 Right, there is a definitive, unyielding link between a star's 348 00:16:41.320 --> 00:16:43.279 mass and its relationship status. 349 00:16:43.320 --> 00:16:44.279 It's fascinating. 350 00:16:44.360 --> 00:16:47.240 If a star is categorized as a heavyweight, meaning it 351 00:16:47.279 --> 00:16:50.120 possesses more than half the mass of our Sun, it 352 00:16:50.159 --> 00:16:52.480 has a massive forty one percent chance of being paired 353 00:16:52.519 --> 00:16:54.360 up with at least one companion. 354 00:16:53.919 --> 00:16:58.080 Almost a coin flip. Mass dictates cosmic sociability. The heavier 355 00:16:58.120 --> 00:16:59.840 the star, the more likely it is to exist in 356 00:16:59.879 --> 00:17:00.840 a complex system. 357 00:17:00.960 --> 00:17:03.360 But then the complete opposite is true for the lightweights. 358 00:17:03.600 --> 00:17:06.759 We're talking about objects under point one solar masses. 359 00:17:06.480 --> 00:17:08.319 Right, the red dwarfs and the brown dwarfs. 360 00:17:08.400 --> 00:17:11.240 Yeah, for these lightweights, the fraction of being found in 361 00:17:11.240 --> 00:17:14.200 a multi star system absolutely plummets. It drops all the 362 00:17:14.240 --> 00:17:16.640 way down to just nine percent. They actively seem to 363 00:17:16.720 --> 00:17:18.759 avoid entanglements, and that. 364 00:17:18.880 --> 00:17:22.319 Massive statistical drop off from forty one percent down to 365 00:17:22.440 --> 00:17:26.839 nine percent is not just a quirk of our local neighborhood. No, No, 366 00:17:27.480 --> 00:17:31.039 it provides crucial forensic evidence for one of the most 367 00:17:31.079 --> 00:17:37.200 intense ongoing debates in stellar astrophysics, the mystery of how 368 00:17:37.319 --> 00:17:39.039 substellar objects actually form. 369 00:17:39.119 --> 00:17:42.759 The first place interesting because I look at gravity like 370 00:17:42.799 --> 00:17:44.839 a form of cosmic social currency. 371 00:17:44.920 --> 00:17:45.680 Social currency. 372 00:17:45.759 --> 00:17:49.599 Yeah, Like, the heavier you are, the more gravitational charisma 373 00:17:49.680 --> 00:17:52.839 you possess, you can attract other bodies, lock them into orbit, 374 00:17:52.920 --> 00:17:55.400 and basically hold on to them through the chaotic early 375 00:17:55.519 --> 00:17:56.559 days of star formation. 376 00:17:56.799 --> 00:17:59.640 That's a great way to visualize it. The heavyweights clearly 377 00:17:59.680 --> 00:18:00.480 have that currency. 378 00:18:00.519 --> 00:18:03.359 They travel in packs, right, But it begs the question 379 00:18:03.440 --> 00:18:06.720 regarding these tiny red and brown dwarfs. Are they born 380 00:18:06.799 --> 00:18:09.720 alone because they simply lack the gravitational mass to attract 381 00:18:09.759 --> 00:18:12.359 a partner, or is something more violent happening? 382 00:18:12.480 --> 00:18:13.000 More violent? 383 00:18:13.039 --> 00:18:15.160 Could they have been born into a larger group dynamic 384 00:18:15.160 --> 00:18:16.319 and then violently kicked out. 385 00:18:16.400 --> 00:18:18.880 Well, you are outlining the two leading models for brown 386 00:18:18.960 --> 00:18:23.000 dwarf formation right there. Oh yep. But to understand the debate, 387 00:18:23.160 --> 00:18:25.400 you first have to look at what a brown dwarf 388 00:18:25.480 --> 00:18:29.440 actually is. It is the ultimate cosmic tweener, a. 389 00:18:29.480 --> 00:18:32.279 Tweener, not a planet, not a star exactly. 390 00:18:32.640 --> 00:18:35.839 It is significantly more massive than a gas giant planet 391 00:18:35.880 --> 00:18:38.720 like Jupiter, but it does not have quite enough mass 392 00:18:38.799 --> 00:18:44.240 to generate the core pressure needed to ignite sustained nuclear fusion. 393 00:18:43.880 --> 00:18:45.720 Of hydrogen, so it never caught fire. 394 00:18:45.920 --> 00:18:49.519 Right. It glows faintly from the residual heat of its formation, 395 00:18:50.039 --> 00:18:53.759 but it is not a true hydrogen burning stars kind 396 00:18:53.759 --> 00:18:57.920 of smoldering exactly. Now, consider the birthplace of stars. They 397 00:18:57.960 --> 00:19:01.640 form in these massive freezing cloud clouds of interstellar gas 398 00:19:01.680 --> 00:19:03.640 and dust called molecular. 399 00:19:03.079 --> 00:19:05.279 Clouds, okay, giant freezing clouds, right. 400 00:19:05.559 --> 00:19:08.039 And as these clouds collapse under their own gravity, they 401 00:19:08.079 --> 00:19:12.519