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 Astronomy 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 --> 00:00:25.199 slumber under the night sky. 7 00:00:26.920 --> 00:00:29.480 Okay, So for our look into the sources today, we're 8 00:00:29.600 --> 00:00:32.960 zooming out, way out, way out, Yeah, past the edge 9 00:00:32.960 --> 00:00:34.679 of our own galaxy, the Milky Way. 10 00:00:34.640 --> 00:00:37.439 And we're focusing on our two closest and probably most 11 00:00:37.439 --> 00:00:38.880 famous galactic neighbors. 12 00:00:38.960 --> 00:00:41.039 Right if you're in the southern hemisphere, you just can't 13 00:00:41.039 --> 00:00:43.759 miss them, the large and small Magellantic Cloud. 14 00:00:43.799 --> 00:00:46.039 There's so much more than just these beautiful patches of 15 00:00:46.119 --> 00:00:48.359 light in the sky though. I mean, for centuries they 16 00:00:48.359 --> 00:00:50.880 were guides for sailors and inspiration. 17 00:00:50.560 --> 00:00:54.640 For poets, sure, but for astronomers they represent something else entirely. 18 00:00:54.799 --> 00:00:59.799 Oh absolutely, for astronomers, these irregular dwarf galaxies are home 19 00:00:59.840 --> 00:01:03.000 to some of the most profound and honestly most frustrating 20 00:01:03.039 --> 00:01:05.560 mysteries in all of galaxy evolution. 21 00:01:05.760 --> 00:01:07.959 And that's why we're looking at this today because this 22 00:01:08.000 --> 00:01:11.079 isn't just about another observation. We're talking about it massive 23 00:01:11.359 --> 00:01:12.799 dedicated research. 24 00:01:12.439 --> 00:01:16.200 Program monumental is the word, a five year program focused 25 00:01:16.319 --> 00:01:18.040 entirely on these two galaxies. 26 00:01:18.280 --> 00:01:21.200 The whole mission here is to take what look like 27 00:01:21.280 --> 00:01:25.480 these these abstract clouds of stars and gas and turn 28 00:01:25.560 --> 00:01:28.400 them into a detailed, meticulous cosmic history. 29 00:01:28.760 --> 00:01:31.400 And that's exactly what we're going to unpack. We are 30 00:01:31.519 --> 00:01:35.239 looking at the sources that detail this new astronomical campaign, 31 00:01:35.640 --> 00:01:39.200 try to figure out what makes these two galaxies the 32 00:01:39.359 --> 00:01:40.879 ultimate cosmic. 33 00:01:40.519 --> 00:01:44.120 Lab, and what are the core scientific puzzles that this 34 00:01:44.280 --> 00:01:46.680 huge data collection is really designed to solve. 35 00:01:46.799 --> 00:01:49.760 Exactly, We want to give you the shortcut to understanding 36 00:01:49.840 --> 00:01:53.640 the secrets that are locked away inside the Magellanic clouds. 37 00:01:54.200 --> 00:01:57.480 So the starting point, the ultimate takeaway, really begins with 38 00:01:57.840 --> 00:02:02.640 just geography, or I guess cosmic geography. Proximity. 39 00:02:03.000 --> 00:02:06.519 Proximity is everything in galactic terms. They are practically on 40 00:02:06.560 --> 00:02:07.159 our doorstep. 41 00:02:07.319 --> 00:02:08.479 How close are we talking. 42 00:02:08.439 --> 00:02:10.960 The LMC, the large one is about one hundred and 43 00:02:11.000 --> 00:02:13.639 sixty three thousand light years away. The SMC is a 44 00:02:13.639 --> 00:02:16.120 little bit further, around two hundred and six thousand. 45 00:02:16.000 --> 00:02:17.840 And just to give you some perspective on that the 46 00:02:17.879 --> 00:02:20.800 next big galaxy, Andromeda is what over two and a 47 00:02:20.800 --> 00:02:21.560 half million light. 48 00:02:21.479 --> 00:02:24.639 Years away, right, So this sheer closeness is what makes 49 00:02:24.639 --> 00:02:26.400 them so scientifically valuable. 50 00:02:26.520 --> 00:02:29.280 Invaluable because they give us a perspective we just can't 51 00:02:29.319 --> 00:02:31.039 get from inside our own galaxy. 52 00:02:31.240 --> 00:02:35.719 Precisely, we can resolve individual stars with incredible clarity. Because 53 00:02:35.759 --> 00:02:39.120 they're so close, we can map out their entire structure, 54 00:02:39.400 --> 00:02:42.759 their stellar populations, the internal dynamics without. 55 00:02:42.520 --> 00:02:44.159 All the clutter of the Milky Way getting in. 56 00:02:44.080 --> 00:02:47.919 The way exactly. The sources call them excellent natural laboratories 57 00:02:48.039 --> 00:02:51.960 for studying things like galaxy evolution and star formation, and 58 00:02:52.000 --> 00:02:54.759 those are processes that are either completely hidden by dust 59 00:02:54.800 --> 00:02:58.360 in our own galaxy or just impossible to see coherently 60 00:02:58.719 --> 00:03:00.960 from where we sit inside the galactic disc. 61 00:03:01.039 --> 00:03:03.439 Okay, so we have the perfect subjects. Now, we need 62 00:03:03.479 --> 00:03:06.080 the team and the tools, and this is a huge 63 00:03:06.080 --> 00:03:09.800 international project, but there's one institution really spear hitting it. 64 00:03:09.960 --> 00:03:12.159 That's right. This whole push is being led by a 65 00:03:12.159 --> 00:03:15.800 new research group at the Libniz Institute for Astrophysics, Potsdam, 66 00:03:15.879 --> 00:03:17.159 the AIP, and. 67 00:03:17.080 --> 00:03:20.120 A key person here is doctor Laura Colinane, yes. 68 00:03:19.960 --> 00:03:22.520 A postdoc at AIP, and her focus is really on 69 00:03:22.520 --> 00:03:25.719 the nitty gritty details, the chemistry the motion of individual 70 00:03:25.759 --> 00:03:27.639 stars within that bigger galactic picture. 71 00:03:27.680 --> 00:03:31.000 And the project itself has this wonderfully grand name one 72 00:03:31.039 --> 00:03:33.240 thousand and one Magellanic. 73 00:03:32.680 --> 00:03:35.599 Fields, mercifully shortened to one thousand and one MC. 74 00:03:36.280 --> 00:03:37.840 It does have a nice ring to it. 75 00:03:37.840 --> 00:03:41.039 It sounds like an adventure, and honestly the scale fits. 76 00:03:41.680 --> 00:03:44.840 The main goal here for doctor Colinane and her colleagues 77 00:03:45.159 --> 00:03:48.680 is to resolve individual stars. We're not talking about just 78 00:03:48.800 --> 00:03:50.199 blurry smudges of light. 79 00:03:50.520 --> 00:03:53.759 No, this is getting down to the component parts exactly. 80 00:03:53.840 --> 00:03:56.159 The idea is that if you can understand the detailed 81 00:03:56.240 --> 00:04:01.000 chemistry and the movement of say half million single stars, 82 00:04:01.560 --> 00:04:03.280 you can piece together the whole. 83 00:04:03.039 --> 00:04:08.199 Life story, the bigger picture, how these galaxies formed, how 84 00:04:08.240 --> 00:04:11.199 they've interacted with each other, how they've changed over billions 85 00:04:11.240 --> 00:04:11.719 of years. 86 00:04:11.919 --> 00:04:14.879 It's like collecting billions of tiny stellar history books to 87 00:04:14.960 --> 00:04:17.839 write the complete biography of the clouds themselves. 88 00:04:18.000 --> 00:04:21.079 You're turning an abstract cloud into a detailed family tree. 89 00:04:21.120 --> 00:04:21.839 That's the mission. 90 00:04:21.920 --> 00:04:24.759 We're moving from just observing the symptoms of galactic evolution 91 00:04:24.879 --> 00:04:27.160 to actually understanding the mechanics behind it. 92 00:04:27.439 --> 00:04:29.759 So let's get a bit deeper into this idea of 93 00:04:29.839 --> 00:04:33.600 than being a superior laboratory. I mean, why is it 94 00:04:33.639 --> 00:04:35.920 so much better than just studying in the Milky Way? 95 00:04:36.040 --> 00:04:38.560 Well, you know that analogy we sometimes use, the one. 96 00:04:38.439 --> 00:04:40.360 About being stuck in a foggy valley. 97 00:04:40.439 --> 00:04:44.160 Exactly that one trying to map our own galaxy from 98 00:04:44.160 --> 00:04:47.680 the inside is it's like that you've got dust, You've 99 00:04:47.680 --> 00:04:48.680 got clutter everywhere. 100 00:04:48.759 --> 00:04:51.319 Extinction right, just blocks the view completely. 101 00:04:51.439 --> 00:04:56.120 But with the Magellanic clouds we get this this holistic view. 102 00:04:56.160 --> 00:04:58.120 We see the whole thing top to bottom. We can 103 00:04:58.120 --> 00:05:02.000 map their entire stellar populations without that heavy interference. 104 00:05:02.399 --> 00:05:06.399 It's more than just the view, right, Their actual physical characteristics. 105 00:05:05.759 --> 00:05:08.240 Are oh, very different, and that's what makes them such 106 00:05:08.279 --> 00:05:11.439 perfect test beds. It's really about their gas content and 107 00:05:12.040 --> 00:05:13.800 you could say their maturity. 108 00:05:13.519 --> 00:05:17.040 And the contrast with the Milky Way is pretty stark. 109 00:05:17.199 --> 00:05:21.000 Absolutely, two main things define them. First, they are way 110 00:05:21.040 --> 00:05:22.199 more gas rich than. 111 00:05:22.040 --> 00:05:24.680 We are, meaning a much higher fraction of their mass 112 00:05:24.759 --> 00:05:27.279 is just raw hydrogen and helium. 113 00:05:26.920 --> 00:05:30.319 The pristine fuel for making new stars exactly, so they have. 114 00:05:30.279 --> 00:05:32.040 A lot of gas left in the tank waiting to 115 00:05:32.079 --> 00:05:32.560 be used. 116 00:05:32.680 --> 00:05:35.519 They do. And second, and this is probably even more 117 00:05:35.560 --> 00:05:39.120 critical for testing our big cosmological models, they have a 118 00:05:39.240 --> 00:05:40.480 much lower metallicity. 119 00:05:40.800 --> 00:05:44.079 Okay, so when astronomers say metallicity, we're talking about all 120 00:05:44.120 --> 00:05:47.079 the elements heavier than hydrogen and helium. Why is it 121 00:05:47.120 --> 00:05:48.879 so important that they have less of that stuff? 122 00:05:49.360 --> 00:05:52.639 Well, low metallicity means the LMC and SMC have had 123 00:05:52.959 --> 00:05:57.199 less chemical enrichment over their lifetimes. Heavy elements are forged 124 00:05:57.240 --> 00:06:00.240 inside stars and then blasted out into the galaxy see 125 00:06:00.240 --> 00:06:03.000 when those stars die, usually in supernovae. 126 00:06:03.160 --> 00:06:06.360 So lower metallicity means a less mature or maybe a 127 00:06:06.439 --> 00:06:09.120 less efficient star making system compared to our own. 128 00:06:09.000 --> 00:06:12.399 Galaxy precisely, and that's what helps us test our models 129 00:06:12.399 --> 00:06:16.439 of galaxy formation. How So, our big cosmological simulations have 130 00:06:16.560 --> 00:06:20.639 always kind of struggled with dwarf galaxies. A key problem 131 00:06:20.680 --> 00:06:23.439 is figuring out how chemical enrichment that build up of 132 00:06:23.480 --> 00:06:27.519 heavy elements actually happens in these small, low mass systems, because. 133 00:06:27.279 --> 00:06:29.040 They don't have enough gravity to hang onto all the 134 00:06:29.079 --> 00:06:31.360 gas that gets blown out by supernovae exactly. 135 00:06:31.600 --> 00:06:34.480 So, the LMC and SMC being both metal poor and 136 00:06:34.600 --> 00:06:38.040 actively forming stars. They let us see star formation happening 137 00:06:38.040 --> 00:06:41.160 in the exact conditions that our theories predict dominated the 138 00:06:41.199 --> 00:06:42.399 early universe. 139 00:06:42.279 --> 00:06:45.079 So we can watch how stars form when the environment 140 00:06:45.120 --> 00:06:48.720 is still relatively pristine, something we just can't do in 141 00:06:48.759 --> 00:06:51.319 the Milky Way's mature, metal rich disc. 142 00:06:51.519 --> 00:06:54.759 They're like living fossils of early galaxy formation. It's an 143 00:06:54.759 --> 00:06:56.720 incredible opportunity. 144 00:06:56.199 --> 00:07:00.000 That context is invaluable. And within these metal poor games 145 00:07:00.079 --> 00:07:02.680 as clouds, there are some specific spots that are just 146 00:07:04.079 --> 00:07:05.839 they're astronomical showstoppers. 147 00:07:05.879 --> 00:07:09.959 They really are cosmic extremes. In the large Magellanic cloud 148 00:07:10.000 --> 00:07:12.879 you've got the tarantulin Nebula was not as thirty durraatus, 149 00:07:12.959 --> 00:07:16.160 and our sources describe it as an extremely active star 150 00:07:16.279 --> 00:07:19.360 forming region, which is frankly an understatement. 151 00:07:19.480 --> 00:07:22.399 It's the most active region of massive star formation in 152 00:07:22.439 --> 00:07:25.480 our entire local group of galaxies, isn't it? It is? 153 00:07:25.600 --> 00:07:28.839 It is an absolute engine room of stellar creation. It 154 00:07:28.879 --> 00:07:31.759 has some of the biggest, most luminous, most massive stars 155 00:07:31.759 --> 00:07:34.680 we know of, Some are dozens of times the mass 156 00:07:34.680 --> 00:07:35.240 of our Sun. 157 00:07:35.600 --> 00:07:38.360 And the fact that a relatively small low metallis city 158 00:07:38.439 --> 00:07:41.839 galaxy like the LMC can host such a monster star 159 00:07:41.959 --> 00:07:43.920 forming region is a puzzle in itself. 160 00:07:44.199 --> 00:07:47.920 It is the radiation and wanes from those newborn giant 161 00:07:48.000 --> 00:07:52.160 stars are just constantly sculpting the gas around them. Studying 162 00:07:52.160 --> 00:07:54.879 them helps us understand the absolute upper limits of star 163 00:07:54.959 --> 00:07:56.079 formation physics. 164 00:07:56.279 --> 00:07:58.759 In the small Magellanic Cloud it has its own version 165 00:07:58.759 --> 00:07:59.040 of those. 166 00:07:59.160 --> 00:08:03.279 It does three six. It's an open star cluster and 167 00:08:03.360 --> 00:08:06.920 nebula that's also actively forming a lot of high mass stars. 168 00:08:06.680 --> 00:08:08.240 So it's another real time test bed. 169 00:08:08.399 --> 00:08:11.680 But crucially it's doing it in the even lower metallicity 170 00:08:11.759 --> 00:08:14.759 environment of the SMC, so we get to observe the 171 00:08:14.800 --> 00:08:18.959 same physics but under slightly different, more primitive chemical conditions. 172 00:08:19.079 --> 00:08:20.680 It's a perfect comparative study. 173 00:08:20.800 --> 00:08:24.439 And beyond these crazy star forming regions, the clouds also 174 00:08:24.480 --> 00:08:28.560 contain objects that are well, they're fundamental to how we 175 00:08:28.600 --> 00:08:29.759 map the entire universe. 176 00:08:29.839 --> 00:08:33.519 You're talking about their huge population of variable stars. Exactly 177 00:08:33.679 --> 00:08:37.840 these stars, specifically the Cepheide variables, are absolutely vital. There 178 00:08:37.879 --> 00:08:40.960 are standard candles for the cosmic distance ladder. 179 00:08:40.720 --> 00:08:43.240 Because the relationship between how fast they pulse and how 180 00:08:43.240 --> 00:08:45.559 bright they truly are is very well. 181 00:08:45.440 --> 00:08:49.000 Understood, extremely well understood, so you can compare their true 182 00:08:49.000 --> 00:08:51.639 brightness to how bright they appear from Earth, and from 183 00:08:51.679 --> 00:08:56.399 that you can calculate their distance with incredible accuracy. 184 00:08:56.080 --> 00:08:58.879 And by extension, the distance to the galaxy they live 185 00:08:58.919 --> 00:08:59.720 in precisely. 186 00:09:00.480 --> 00:09:03.279 And because the Magellanic clouds are so close, we can 187 00:09:03.279 --> 00:09:08.600 make hyper accurate foundational distance measurements to their cepheides. Those 188 00:09:08.679 --> 00:09:12.799 distances then calibrate the entire cosmic distance scale. 189 00:09:12.600 --> 00:09:15.120 The yardstick we use to measure the whole universe, all 190 00:09:15.159 --> 00:09:17.120 the way up to calculate in the Hubble constant and 191 00:09:17.200 --> 00:09:18.000 the expansion rate. 192 00:09:18.120 --> 00:09:21.360 Right, So, detailed data on the variable stars in the 193 00:09:21.480 --> 00:09:25.159 LMC and SMC is bedrock science for the whole field. 194 00:09:25.399 --> 00:09:27.600 It sounds like they're just constantly churning out stars and 195 00:09:27.679 --> 00:09:29.960 lighting up the cosmos. But you mentioned there's a kind 196 00:09:30.000 --> 00:09:33.639 of inconsistency to their activity levels, not a smooth process. 197 00:09:33.200 --> 00:09:35.399 And this is maybe the most fundamental question about their 198 00:09:35.440 --> 00:09:38.320 internal life that this one thousand and one MC survey 199 00:09:38.399 --> 00:09:40.919 wants to answer. The sources show that even though the 200 00:09:40.919 --> 00:09:43.720 clouds have stars of all ages from very young to 201 00:09:43.840 --> 00:09:47.519 very old, the rate of star formation hasn't been constant. 202 00:09:47.720 --> 00:09:50.360 It seems to happen in what they call episodic bursts. 203 00:09:50.840 --> 00:09:56.679 Exactly episodic brusts, which suggests long periods of relative quiet 204 00:09:56.919 --> 00:10:01.440 punctuated by these intense, spectacular fire displays of starbirth. 205 00:10:01.559 --> 00:10:04.000 But what's pushing the on switch for those fireworks? 206 00:10:04.000 --> 00:10:07.080 That is the core puzzle why the bursts. Is the 207 00:10:07.120 --> 00:10:10.240 gas compression that you need to trigger mass star formation 208 00:10:10.440 --> 00:10:14.480 coming from something internal like complex gas dynamics within the 209 00:10:14.519 --> 00:10:15.360 galaxy itself? 210 00:10:15.440 --> 00:10:16.759 Or is the trigger external? 211 00:10:16.879 --> 00:10:19.879 Right? Is it the gravitational or physical interaction with the 212 00:10:19.919 --> 00:10:22.960 Milky Way, or even just the frequent close passes between 213 00:10:23.000 --> 00:10:25.000 the LMAC and the SMC themselves. 214 00:10:25.480 --> 00:10:27.679 And the source suggests that if the bursts line up 215 00:10:27.679 --> 00:10:31.159 with the times of close gravitational encounters, that would point 216 00:10:31.279 --> 00:10:32.919 very strongly to an external trigger. 217 00:10:33.039 --> 00:10:36.960 Absolutely, a gravitational shockwave from a close pass can compress 218 00:10:37.000 --> 00:10:39.480 gas and kick off a huge wave of star formation. 219 00:10:40.159 --> 00:10:43.080 But to know that for sure, we need hard data. 220 00:10:43.399 --> 00:10:45.799 We need the precise ages and the motions of the 221 00:10:45.840 --> 00:10:47.519 stars that were born in those bursts. 222 00:10:47.519 --> 00:10:49.919 To verify that connection, we need to figure out who's 223 00:10:49.960 --> 00:10:52.799 pushing the nitro button that accelerates everything. 224 00:10:52.480 --> 00:10:55.320 And that leads us perfectly into the instruments that are 225 00:10:55.320 --> 00:10:56.240 designed to find out. 226 00:10:56.519 --> 00:10:59.399 Okay, So if the clouds of the perfect lab. You 227 00:10:59.480 --> 00:11:03.240 need the perfect tools, and the instruments for this are well, 228 00:11:03.279 --> 00:11:08.200 they're pretty incredible. Right down at the Paranol Observatory in Chile, Oh. 229 00:11:07.799 --> 00:11:09.960 The hardware is state of the art. It all centers 230 00:11:10.000 --> 00:11:11.080 on the Vista Telescope. 231 00:11:11.159 --> 00:11:15.039 VISTA. That's the visible and infrared survey telescope for astronomy. 232 00:11:14.639 --> 00:11:17.120 Right, but it's just been given this massive upgrade a 233 00:11:17.159 --> 00:11:19.360 new instrument called Foremost. 234 00:11:18.919 --> 00:11:23.679 Four meter multi object spectrograph telescope, So it's spectrograph. 235 00:11:23.240 --> 00:11:27.039 Exactly, which is attached to Vista. Let's start with Visit 236 00:11:27.120 --> 00:11:30.360 itself though. It's got a huge four point one meter 237 00:11:30.519 --> 00:11:31.840 primary mirror. 238 00:11:31.480 --> 00:11:34.840 But its real specialty is its vision. It sees in 239 00:11:34.879 --> 00:11:36.320 the near infrared. 240 00:11:36.039 --> 00:11:40.480 And that near infrared or NR capability is just crucial. 241 00:11:40.879 --> 00:11:43.519 Vista is the largest telescope in the world dedicated to 242 00:11:43.600 --> 00:11:45.279 wide field surveys in the NIR. 243 00:11:45.600 --> 00:11:47.320 Why is NR so important for this. 244 00:11:47.440 --> 00:11:50.080 Because it lets you see through the dust Galactic dust 245 00:11:50.120 --> 00:11:53.039 particles that block visible light are well, they're basically transparent 246 00:11:53.080 --> 00:11:55.679 to the longer wavelengths of near infrared light, so. 247 00:11:55.600 --> 00:11:57.639 You're not just seeing the bright stars on the surface 248 00:11:57.679 --> 00:12:01.360 of the clouds. You're actually peering right into the heart 249 00:12:01.440 --> 00:12:04.559 of those star forming regions, like deep inside the transil 250 00:12:04.559 --> 00:12:05.720 and neibula precisely. 251 00:12:05.960 --> 00:12:08.399 It lets them do an accurate census of stars that 252 00:12:08.399 --> 00:12:12.360 would be completely invisible in a normal optical light survey. 253 00:12:12.559 --> 00:12:15.360 It's essential for getting a complete, unbiased sample. 254 00:12:15.559 --> 00:12:18.679 And the camera on this thing is it's a monster, 255 00:12:19.480 --> 00:12:22.600 a three ton sixty seven megapixel camera. 256 00:12:22.840 --> 00:12:26.840 It's stunning technology. But Foremost is the new brain of 257 00:12:26.879 --> 00:12:29.559 the operation. That's the upgrade that takes all that light 258 00:12:29.639 --> 00:12:32.279 gathering power and turns it into historical evidence. 259 00:12:32.480 --> 00:12:35.279 A multi object spectrograph what does that actually mean. 260 00:12:35.519 --> 00:12:39.120 It's a fiber fed spectroscopic survey instrument, and the multi 261 00:12:39.240 --> 00:12:41.320 object part is the real game changer. 262 00:12:41.480 --> 00:12:43.279 Instead of looking at one start a time. 263 00:12:43.240 --> 00:12:45.159 Right, instead of pointing at a single star to get 264 00:12:45.200 --> 00:12:49.320 its spectrum, Foremost has this complex robotic positioner that moves 265 00:12:49.440 --> 00:12:52.639 thousands of tiny little optical fibers across the focal plane. 266 00:12:52.679 --> 00:12:54.080 How many targets could I hit at once? 267 00:12:54.200 --> 00:12:56.279 It can collect light from up to twenty four hundred 268 00:12:56.279 --> 00:13:00.000 different objects simultaneously in a single observation twenty four hundre 269 00:13:00.200 --> 00:13:04.320 so it's basically doing twenty four hundred separate spectroscopic measurements 270 00:13:04.639 --> 00:13:06.720 in the time it would have taken older instruments to 271 00:13:06.799 --> 00:13:09.320 do maybe one or two. It's the only way you 272 00:13:09.360 --> 00:13:11.039 could hope to get a sample size of half a 273 00:13:11.080 --> 00:13:12.639 million stars in a reasonable time. 274 00:13:12.759 --> 00:13:16.279 That just completely changes the logistics of a survey like this. 275 00:13:16.399 --> 00:13:17.559 So what's the timeline. 276 00:13:17.639 --> 00:13:21.320 This is all happening right now. Foremost achieved first light 277 00:13:21.759 --> 00:13:24.879 back in October twenty twenty five. It's in its commissioning 278 00:13:24.879 --> 00:13:27.879 phase as we speak, getting everything calibrated. 279 00:13:27.399 --> 00:13:29.759 And science operations are scheduled to start. 280 00:13:29.559 --> 00:13:32.799 Soon second quarter of twenty twenty six. And here's the kicker, 281 00:13:32.879 --> 00:13:35.080 the thing that shows you how important this mission is. 282 00:13:35.679 --> 00:13:38.840 For a stripped five year period, this to and Foremost 283 00:13:38.919 --> 00:13:43.120 are completely dedicated to this program. It excludes all other observations. 284 00:13:43.200 --> 00:13:46.360 Wow, a five year block on a world class telescope. 285 00:13:46.519 --> 00:13:49.240 That's an enormous commitment of astronomical resources. 286 00:13:49.240 --> 00:13:51.759 It is which brings us to the mission itself, one 287 00:13:51.759 --> 00:13:52.480 thousand and one. 288 00:13:52.399 --> 00:13:55.799 MC, the one thousand and one Magellanic Fields co led 289 00:13:55.879 --> 00:13:57.039 by doctor Colinade. 290 00:13:57.080 --> 00:13:59.600 The ambition is just staggering. The goal is to get 291 00:13:59.639 --> 00:14:02.120 the spec of about half a million stars across the 292 00:14:02.159 --> 00:14:05.399 main bodies of the clouds and just as importantly, way 293 00:14:05.480 --> 00:14:08.039 out into their faint, outlying regions. 294 00:14:07.879 --> 00:14:12.879 Half a million individual stellar life stories. So for someone listening, 295 00:14:13.120 --> 00:14:16.279 what's the really crucial data that the spectrograph gives you 296 00:14:16.399 --> 00:14:18.159 that you can't get from just a picture. 297 00:14:18.480 --> 00:14:21.799 It gives you two revolutionary types of data. First, high 298 00:14:21.840 --> 00:14:24.320 precision elemental abundances. 299 00:14:23.759 --> 00:14:27.080 The star's chemical fingerprint, it's Perth certificate exactly. 300 00:14:27.600 --> 00:14:31.639 And second, extremely accurate kinematics. 301 00:14:31.360 --> 00:14:35.200 Which is its detailed motion, its travel history, it's velocity 302 00:14:35.240 --> 00:14:36.559 toward us or away from us. 303 00:14:36.840 --> 00:14:39.039 Let's drill down on those abundances for a second. When 304 00:14:39.039 --> 00:14:42.159 you say chemical fingerprint, which elements tell you the most 305 00:14:42.200 --> 00:14:43.000 about the history? 306 00:14:43.200 --> 00:14:45.080 I assume things like iron are important. 307 00:14:45.399 --> 00:14:49.480 Iron is key, yes, for overall metallicity, but also what 308 00:14:49.519 --> 00:14:53.519 are called the alpha elements, things like magnesium and titanium. 309 00:14:53.799 --> 00:14:56.639 The ratio of iron to these alpha elements is super 310 00:14:56.679 --> 00:15:00.360 sensitive to the history of star formation. No so, because slow, 311 00:15:00.480 --> 00:15:03.840 steady rate of star formation produces a different chemical ratio 312 00:15:03.960 --> 00:15:07.000 than a rapid, intense burst, does it tells you about 313 00:15:07.039 --> 00:15:09.080 the rate of enrichment, not just the amount. 314 00:15:08.879 --> 00:15:11.679 And the kinematics. How does the spectrograph measure motion? 315 00:15:12.080 --> 00:15:15.120 It all comes down to the Doppler effect. Light from 316 00:15:15.120 --> 00:15:18.080 a star moving toward use gets slightly blue. 317 00:15:17.759 --> 00:15:20.399 Shifted, its wavelengths get compressed right. 318 00:15:20.519 --> 00:15:22.759 And light from a star moving away gets red shifted, 319 00:15:22.799 --> 00:15:25.879 its wavelengths get stretched, And you need a high resolution 320 00:15:26.000 --> 00:15:30.039 spectrograph to measure those tiny shifts with enough precision to 321 00:15:30.080 --> 00:15:34.080 get the star's velocity down to say a kilometer per second. 322 00:15:34.279 --> 00:15:36.919 So you get the star's life history from its chemistry 323 00:15:37.039 --> 00:15:39.679 and its current path from its motion and Doctor Colony 324 00:15:39.720 --> 00:15:43.120 and specifically mentioned measuring this data in the outskirts. 325 00:15:43.360 --> 00:15:46.759 Why is that so important, Because the outskirts the halos 326 00:15:46.799 --> 00:15:48.840 of these galaxies are where the tug of war is 327 00:15:48.879 --> 00:15:52.679 most obvious. If the Milky Way is tidally pulling material 328 00:15:52.720 --> 00:15:55.600 off the clouds, it's going to strip the stars and 329 00:15:55.639 --> 00:15:57.120 gas from the edges first. 330 00:15:57.159 --> 00:15:59.320 Those are the regions that are most weakly held on 331 00:15:59.360 --> 00:16:00.159 by the clouds side. 332 00:16:00.200 --> 00:16:03.320 Gravity exactly, and they're very faint, which is why you 333 00:16:03.399 --> 00:16:07.399 need Vista's wide field and niur sensitivity and foremost ability 334 00:16:07.440 --> 00:16:09.320 to target faint stars so efficiently. 335 00:16:09.600 --> 00:16:12.480 Her quote really sums it all up, doesn't it. She said. 336 00:16:12.480 --> 00:16:15.240 The goal is to trace the effects of interactions between 337 00:16:15.240 --> 00:16:19.360 the clouds by analyzing the kinematics and abundances of their 338 00:16:19.399 --> 00:16:22.320 stellar populations, particularly in the outskirts. 339 00:16:22.559 --> 00:16:25.360 That's it in a nutshell. The focus is on finding 340 00:16:25.399 --> 00:16:29.320 the physical scars left by these massive gravitational fights. 341 00:16:29.600 --> 00:16:32.879 So this incredible new data set is really designed to 342 00:16:32.960 --> 00:16:37.000 test some of the biggest, most revolutionary ideas happening in 343 00:16:37.080 --> 00:16:40.600 galactic dynamics right now. For decades, we had a pretty 344 00:16:40.600 --> 00:16:43.279 comfortable story about how the Milky Way and the clouds 345 00:16:43.279 --> 00:16:44.000 were interacting. 346 00:16:44.159 --> 00:16:47.000 We did. The old paradigm was that the clouds were 347 00:16:47.039 --> 00:16:50.120 ancient satellites. They had been orbiting the Milky Way for 348 00:16:50.320 --> 00:16:54.159 maybe ten billion years. They'd completed lots of passes. 349 00:16:53.759 --> 00:16:57.360 Which implied a long slow history of co evolution, a very. 350 00:16:57.240 --> 00:16:59.639 Long slow dance. But the sources are clear that this 351 00:16:59.759 --> 00:17:02.720 law held idea has just been completely challenged, and that's 352 00:17:02.759 --> 00:17:05.000 what created the urgency for one thousand and one MC. 353 00:17:05.319 --> 00:17:07.720 What was it that shifted the foundation of that theory. 354 00:17:07.880 --> 00:17:10.880 The shift came from the ESA's Gaya Mission Ayah, which. 355 00:17:10.759 --> 00:17:13.119 Is just mapping everything with insane precision. 356 00:17:13.440 --> 00:17:17.160 Insane precision. Its strength is mapping the positions and the 357 00:17:17.160 --> 00:17:21.799 proper motions. That's the sideways movement of billions of stars, 358 00:17:22.160 --> 00:17:24.839 and that data, when you combine it with some older 359 00:17:25.000 --> 00:17:30.039 Hubble observations, it suggests something well, something revolutionary, which is 360 00:17:30.200 --> 00:17:32.759 that the clouds might be on their very first passage 361 00:17:32.799 --> 00:17:33.559 by the Milky Way. 362 00:17:33.640 --> 00:17:38.440 Hold on their first pass not ancient satellites that have 363 00:17:38.559 --> 00:17:40.240 been orbiting for billions. 364 00:17:39.839 --> 00:17:42.720 Of years exactly. They might just be newcomers, just arriving 365 00:17:42.960 --> 00:17:44.920 in our cosmic neighborhood for the first time. 366 00:17:45.119 --> 00:17:48.039 That's a massive revision of their history. If they're new, 367 00:17:48.079 --> 00:17:51.000 it means all the dramatic effects we see, the star formation, 368 00:17:51.200 --> 00:17:53.400 the gas streams, all of that has to be the 369 00:17:53.440 --> 00:17:56.960 result of a fresh, violent, rapid encounter, not. 370 00:17:56.960 --> 00:18:00.799 A slow, billions of years long orbital decay. That's the 371 00:18:00.839 --> 00:18:04.160 profound implication. If they're on a first pass, their relationship 372 00:18:04.200 --> 00:18:06.400 with the Milky Way has only just begun. 373 00:18:06.240 --> 00:18:08.880 And that has to have huge implications for understanding our 374 00:18:08.880 --> 00:18:09.759 own galaxy too. 375 00:18:10.119 --> 00:18:13.440 Oh massive. It changes our estimates for the total mass 376 00:18:13.440 --> 00:18:15.920 of the Milky Way, because if the clouds are moving 377 00:18:15.960 --> 00:18:19.160 fast enough to just be passing through, our galaxy has 378 00:18:19.200 --> 00:18:21.880 to be heavy enough to have captured them only temporarily, 379 00:18:22.079 --> 00:18:23.359 or to be pulling them into orbit. 380 00:18:23.440 --> 00:18:26.319 Right now, not having held onto them for eons. It 381 00:18:26.319 --> 00:18:29.880 affects our understanding of our own dark matter halo absolutely. 382 00:18:30.319 --> 00:18:33.240 And the most dramatic piece of evidence for this interaction, 383 00:18:33.319 --> 00:18:36.720 whether it's old or new, is the huge stream of 384 00:18:36.759 --> 00:18:39.559 material we see being ripped away from the clouds right now, 385 00:18:39.799 --> 00:18:43.559 the Magelanic stream, the Magelanic stream, this enormous ribbon of 386 00:18:43.599 --> 00:18:46.839 gas that trails hundreds of thousands of light years behind 387 00:18:46.880 --> 00:18:50.119 the clouds, stretching down toward the Milky Way's south pole. 388 00:18:50.680 --> 00:18:53.359 And there's also the leading arm, which is material fling 389 00:18:53.400 --> 00:18:54.039 out ahead of them. 390 00:18:54.359 --> 00:18:57.319 These things are just immense physical scars that shows something 391 00:18:57.359 --> 00:18:58.799 dramatic is happening. 392 00:18:58.599 --> 00:19:03.240 And their very existence immediately raises three competing ideas about 393 00:19:03.279 --> 00:19:05.559 how they were created, which is what one thousand and 394 00:19:05.559 --> 00:19:07.359 one MC is perfectly designed to test. 395 00:19:07.519 --> 00:19:10.640 We need to figure out which force is responsible because 396 00:19:10.680 --> 00:19:12.839 each one leaves a different kind of signature. 397 00:19:13.119 --> 00:19:16.359 That's the challenge. Is it hypothesis one, two, or three 398 00:19:16.519 --> 00:19:18.680 or a mix of all of them? And the key 399 00:19:18.720 --> 00:19:21.319 to figuring it out is in the kinematic and chemical 400 00:19:21.440 --> 00:19:23.119 data from one thousand and one MC. 401 00:19:23.359 --> 00:19:26.359