1 00:00:00,000 --> 00:00:04,280 Welcome back to Cosmos in a Pods Space and Astronomy series. 2 00:00:04,280 --> 00:00:06,160 You know, today we're gonna be taking a deep dive 3 00:00:06,160 --> 00:00:09,160 into something pretty incredible. 4 00:00:09,160 --> 00:00:10,000 Oh yeah. 5 00:00:10,000 --> 00:00:11,160 Sagittarius A. 6 00:00:11,160 --> 00:00:14,120 Yeah, Sagittarius A, the supermassive black hole 7 00:00:14,120 --> 00:00:15,320 at the center of our galaxy. 8 00:00:15,320 --> 00:00:17,960 The center of our galaxy, isn't that wild? 9 00:00:17,960 --> 00:00:20,640 Like here we are on this tiny little planet 10 00:00:20,640 --> 00:00:23,160 orbiting a pretty average star. 11 00:00:23,160 --> 00:00:24,000 Right. 12 00:00:24,000 --> 00:00:27,940 And yet at the heart of it all is this monster of gravity, 13 00:00:27,940 --> 00:00:30,940 millions of times heavier than our sun. 14 00:00:30,940 --> 00:00:33,180 Yeah, it's mind boggling how massive it is. 15 00:00:33,180 --> 00:00:35,380 And for a long time we didn't even know it was there. 16 00:00:35,380 --> 00:00:37,420 So how did we uncover this hidden giant? 17 00:00:37,420 --> 00:00:39,260 I mean, you can't just point a telescope 18 00:00:39,260 --> 00:00:40,660 at a black hole and see it. 19 00:00:40,660 --> 00:00:43,500 Right, well that's where radio astronomy comes into play 20 00:00:43,500 --> 00:00:45,860 because it lets us see the universe not in light, 21 00:00:45,860 --> 00:00:47,420 but in radio waves. 22 00:00:47,420 --> 00:00:50,460 And that's how Sagittarius A was first detected. 23 00:00:50,460 --> 00:00:53,460 Astronomers picked up this super strong radio signal 24 00:00:53,460 --> 00:00:54,940 coming from the galactic center. 25 00:00:54,940 --> 00:00:57,820 And that's a region already packed with stars and gas 26 00:00:57,820 --> 00:00:58,980 and dust clouds. 27 00:00:58,980 --> 00:01:00,780 It's like finding a needle in a cosmic haystack. 28 00:01:00,780 --> 00:01:01,620 It really is. 29 00:01:01,620 --> 00:01:04,940 So they named this mysterious source Sagittarius A 30 00:01:04,940 --> 00:01:07,980 and it became a prime target for further investigation. 31 00:01:07,980 --> 00:01:09,340 But how did they know it was a black hole? 32 00:01:09,340 --> 00:01:11,300 Was it just the radio signal itself? 33 00:01:11,300 --> 00:01:13,620 Not quite, it took decades more observations 34 00:01:13,620 --> 00:01:16,140 to confirm what it really was. 35 00:01:16,140 --> 00:01:18,540 Astronomers started tracking the movement of stars 36 00:01:18,540 --> 00:01:21,020 orbiting super close to this invisible source. 37 00:01:21,020 --> 00:01:21,860 Oh wow. 38 00:01:21,860 --> 00:01:24,260 And what they saw was amazing. 39 00:01:24,260 --> 00:01:28,180 These stars were whipping around at ridiculous speeds, 40 00:01:28,180 --> 00:01:30,460 millions of kilometers per hour. 41 00:01:30,460 --> 00:01:31,940 Like a cosmic demolition derby. 42 00:01:31,940 --> 00:01:32,780 It is. 43 00:01:32,780 --> 00:01:35,620 And the only way those speeds were possible 44 00:01:35,620 --> 00:01:38,580 is if there was an incredibly massive and compact object 45 00:01:38,580 --> 00:01:41,820 exerting this huge gravitational pull. 46 00:01:41,820 --> 00:01:43,620 And that's a super massive black hole. 47 00:01:43,620 --> 00:01:45,260 So we're basically using these stars 48 00:01:45,260 --> 00:01:46,660 as like cosmic speedometers. 49 00:01:46,660 --> 00:01:47,500 Yeah, exactly. 50 00:01:47,500 --> 00:01:49,260 To figure out how massive this thing is. 51 00:01:49,260 --> 00:01:52,180 And then in 2022, we got the clincher. 52 00:01:52,180 --> 00:01:53,020 Okay. 53 00:01:53,020 --> 00:01:54,300 The Event Horizon Telescope. 54 00:01:54,300 --> 00:01:55,140 Yes. 55 00:01:55,140 --> 00:01:57,020 Which is this network of radio telescopes 56 00:01:57,020 --> 00:01:57,860 all around the globe. 57 00:01:57,860 --> 00:01:58,700 Yeah. 58 00:01:58,700 --> 00:02:02,200 Captured the very first image of Sagittarius A. 59 00:02:02,200 --> 00:02:03,140 Wait, an actual image. 60 00:02:03,140 --> 00:02:04,540 I thought black holes were invisible. 61 00:02:04,540 --> 00:02:06,140 You can't see the black hole itself. 62 00:02:06,140 --> 00:02:08,100 No, because light can't escape it. 63 00:02:08,100 --> 00:02:10,900 But what the Event Horizon Telescope captured 64 00:02:10,900 --> 00:02:12,660 was the black hole shadow. 65 00:02:12,660 --> 00:02:13,500 Okay. 66 00:02:13,500 --> 00:02:15,820 So you've got this dark silhouette 67 00:02:15,820 --> 00:02:19,260 surrounded by this glowing ring of gas and dust. 68 00:02:19,260 --> 00:02:20,100 Wow. 69 00:02:20,100 --> 00:02:22,820 That's being warped and accelerated by the immense gravity. 70 00:02:22,820 --> 00:02:24,300 It was groundbreaking, you know, 71 00:02:24,300 --> 00:02:26,780 confirmed decades of theoretical work. 72 00:02:26,780 --> 00:02:27,620 Yeah. 73 00:02:27,620 --> 00:02:29,500 And gave us this glimpse into one of the most 74 00:02:29,500 --> 00:02:31,540 extreme environments in the universe. 75 00:02:31,540 --> 00:02:32,360 It's incredible. 76 00:02:32,360 --> 00:02:34,860 So we have this super massive black hole, 77 00:02:34,860 --> 00:02:39,180 Sagittarius A lurking at the center of our galaxy. 78 00:02:39,180 --> 00:02:41,620 Besides the obvious, you know, black hole thing. 79 00:02:41,620 --> 00:02:42,460 Yeah. 80 00:02:42,460 --> 00:02:43,860 What else makes it so unique? 81 00:02:43,860 --> 00:02:45,240 Well, one of the most interesting things 82 00:02:45,240 --> 00:02:48,540 about Sagittarius A is that it's surprisingly quiet. 83 00:02:48,540 --> 00:02:49,380 Quiet? 84 00:02:49,380 --> 00:02:52,180 Yeah, compared to other super massive black holes 85 00:02:52,180 --> 00:02:53,020 in other galaxies, 86 00:02:53,020 --> 00:02:55,500 it's not gobbling up matter as aggressively. 87 00:02:55,500 --> 00:02:57,260 So it's not a cosmic vacuum cleaner? 88 00:02:57,260 --> 00:02:58,220 No, not exactly. 89 00:02:58,220 --> 00:03:00,340 It does have these occasional bursts of activity. 90 00:03:00,340 --> 00:03:02,320 We call them flares, where we see these spikes 91 00:03:02,320 --> 00:03:04,460 in X-ray and infrared radiation. 92 00:03:04,460 --> 00:03:06,340 It's like it's snacking on a gas cloud 93 00:03:06,340 --> 00:03:08,700 or an unlucky star that wanders too close. 94 00:03:08,700 --> 00:03:10,020 So it's more like a cosmic cat 95 00:03:10,020 --> 00:03:11,520 just kind of playing with its food? 96 00:03:11,520 --> 00:03:13,860 Yeah, that's a good analogy. 97 00:03:13,860 --> 00:03:15,820 But even though it's pretty calm right now, 98 00:03:15,820 --> 00:03:17,980 Sagittarius A still has a big influence 99 00:03:17,980 --> 00:03:19,060 on everything around it. 100 00:03:19,060 --> 00:03:21,340 So what's it like in the neighborhood of Sagittarius A? 101 00:03:21,340 --> 00:03:23,180 Is it just a vast, empty expanse? 102 00:03:23,180 --> 00:03:24,100 Oh no, not at all. 103 00:03:24,100 --> 00:03:27,120 The galactic center is like this bustling metropolis 104 00:03:27,120 --> 00:03:28,500 of celestial objects. 105 00:03:28,500 --> 00:03:29,580 Oh wow. Yeah. 106 00:03:29,580 --> 00:03:33,560 It's full of stars and gas clouds and dust, 107 00:03:33,560 --> 00:03:37,740 all swirling around Sagittarius A at insane speeds. 108 00:03:37,740 --> 00:03:38,740 So a bit chaotic. 109 00:03:38,740 --> 00:03:39,840 Oh yeah. 110 00:03:39,840 --> 00:03:42,900 Imagine a cosmic traffic jam with massive stars 111 00:03:42,900 --> 00:03:46,460 just whizzing by you at millions of kilometers per hour. 112 00:03:46,460 --> 00:03:47,780 I think I'll stick to Earth traffic. 113 00:03:47,780 --> 00:03:49,140 Probably a good idea. 114 00:03:49,140 --> 00:03:51,980 So how does Sagittarius A fit into all of this? 115 00:03:51,980 --> 00:03:54,860 What's its role in all this cosmic chaos? 116 00:03:54,860 --> 00:03:58,540 Think of it as the conductor of a grand galactic orchestra. 117 00:03:58,540 --> 00:04:01,820 Its immense gravity is kind of like a stabilizing force 118 00:04:01,820 --> 00:04:05,100 keeping the whole galactic center from flying apart. 119 00:04:05,100 --> 00:04:06,460 It also plays this crucial role 120 00:04:06,460 --> 00:04:08,140 in the life and death of stars. 121 00:04:08,140 --> 00:04:10,300 Wait a minute, how does a black hole influence stars 122 00:04:10,300 --> 00:04:11,340 being born and dying? 123 00:04:11,340 --> 00:04:12,620 I thought they were just destroyers 124 00:04:12,620 --> 00:04:13,700 just sucking things in. 125 00:04:13,700 --> 00:04:15,260 That's a common misconception. 126 00:04:15,260 --> 00:04:16,540 They do have that reputation, 127 00:04:16,540 --> 00:04:19,340 but they can also act like cosmic gardeners. 128 00:04:19,340 --> 00:04:20,900 Cosmic gardeners, what do you mean? 129 00:04:20,900 --> 00:04:23,380 Well, so you have these powerful outflows 130 00:04:23,380 --> 00:04:26,380 of energy and radiation from Sagittarius A. 131 00:04:26,380 --> 00:04:29,180 And they can actually trigger new stars to form. 132 00:04:29,180 --> 00:04:30,020 Really? 133 00:04:30,020 --> 00:04:31,740 Yeah, because when those outflows slam 134 00:04:31,740 --> 00:04:34,900 into nearby gas clouds, it compresses them 135 00:04:34,900 --> 00:04:37,620 and causes them to collapse under their own gravity. 136 00:04:37,620 --> 00:04:38,460 Wow. 137 00:04:38,460 --> 00:04:40,180 And then boom, new stars are born. 138 00:04:40,180 --> 00:04:42,140 So it's like destruction leading to creation. 139 00:04:42,140 --> 00:04:44,660 Exactly, but it gets even more interesting 140 00:04:44,660 --> 00:04:48,420 because Sagittarius A can also suppress star formation. 141 00:04:48,420 --> 00:04:49,260 Really? 142 00:04:49,260 --> 00:04:51,780 Yeah, in some regions the intense radiation 143 00:04:51,780 --> 00:04:53,900 can heat up surrounding gas, 144 00:04:53,900 --> 00:04:56,460 making it too diffuse to collapse and form stars. 145 00:04:56,460 --> 00:04:58,220 So it's like a cosmic double agent. 146 00:04:58,220 --> 00:04:59,060 You could say that. 147 00:04:59,060 --> 00:05:00,940 It's amazing how something so powerful 148 00:05:00,940 --> 00:05:03,660 can have such diverse effects on its surroundings. 149 00:05:03,660 --> 00:05:04,620 It really is. 150 00:05:04,620 --> 00:05:06,500 But with all this activity going on, 151 00:05:07,380 --> 00:05:10,020 how do scientists even study it? 152 00:05:10,020 --> 00:05:12,100 It's incredibly far away. 153 00:05:12,100 --> 00:05:13,940 And we've established that it's pretty difficult 154 00:05:13,940 --> 00:05:14,780 to see directly. 155 00:05:14,780 --> 00:05:15,700 Yeah, that's a great point. 156 00:05:15,700 --> 00:05:17,340 It's like trying to study a firefly 157 00:05:17,340 --> 00:05:19,460 in the middle of a fireworks display. 158 00:05:19,460 --> 00:05:22,580 Right, but astronomers have these incredible tools 159 00:05:22,580 --> 00:05:25,140 and techniques to help them overcome these obstacles. 160 00:05:25,140 --> 00:05:26,460 Well, I'm all ears. 161 00:05:26,460 --> 00:05:28,380 What's in their cosmic toolkit? 162 00:05:28,380 --> 00:05:31,500 Well, one of their most powerful tools is radio astronomy, 163 00:05:31,500 --> 00:05:33,140 which like we talked about before, 164 00:05:33,140 --> 00:05:35,340 lets us see through all that dust and gas 165 00:05:35,340 --> 00:05:37,940 that blocks our view of the galactic center. 166 00:05:37,940 --> 00:05:39,660 Right, like cosmic x-ray vision. 167 00:05:39,660 --> 00:05:40,500 Yeah. 168 00:05:40,500 --> 00:05:43,220 But how do they actually use radio waves 169 00:05:43,220 --> 00:05:47,260 to study something as, well, invisible as a black hole? 170 00:05:47,260 --> 00:05:49,820 Okay, so imagine you're trying to study a lighthouse 171 00:05:49,820 --> 00:05:50,900 that's really far away. 172 00:05:50,900 --> 00:05:53,060 You can't actually see the light itself, 173 00:05:53,060 --> 00:05:54,060 because it's too far. 174 00:05:54,060 --> 00:05:55,460 But you can see the beam of light 175 00:05:55,460 --> 00:05:57,140 as it sweeps across the horizon. 176 00:05:57,140 --> 00:05:57,980 Right, yeah. 177 00:05:57,980 --> 00:05:59,020 So in a similar way, 178 00:05:59,020 --> 00:06:02,220 astronomers can't see Sagittarius A directly, 179 00:06:02,220 --> 00:06:04,020 but they can study the radio waves 180 00:06:04,020 --> 00:06:05,740 coming from the hot gas and dust 181 00:06:05,740 --> 00:06:07,060 that are swirling around it. 182 00:06:07,060 --> 00:06:08,780 So it's like they're watching the swirling patterns 183 00:06:08,780 --> 00:06:10,380 to track the black hole's movements. 184 00:06:10,380 --> 00:06:11,220 Exactly. 185 00:06:11,220 --> 00:06:13,460 And to get the clearest view possible, 186 00:06:13,460 --> 00:06:15,740 they use a technique called VLBI. 187 00:06:15,740 --> 00:06:16,580 VLBI. 188 00:06:16,580 --> 00:06:19,180 Yeah, very long baseline interferometry. 189 00:06:19,180 --> 00:06:20,020 Okay. 190 00:06:20,020 --> 00:06:21,220 And that involves combining data 191 00:06:21,220 --> 00:06:24,020 from lots of different radio telescopes around the world. 192 00:06:24,020 --> 00:06:24,860 Wow. 193 00:06:24,860 --> 00:06:26,360 Creating a virtual telescope 194 00:06:26,360 --> 00:06:28,740 that has the resolution of a single dish 195 00:06:28,740 --> 00:06:30,820 that's thousands of kilometers wide. 196 00:06:30,820 --> 00:06:32,340 So it's a real team effort. 197 00:06:32,340 --> 00:06:33,160 It is. 198 00:06:33,160 --> 00:06:35,580 But radio waves aren't the only tool in their arsenal, right? 199 00:06:35,580 --> 00:06:38,700 Right, astronomers also use infrared and x-ray telescopes. 200 00:06:38,700 --> 00:06:39,540 Okay. 201 00:06:39,540 --> 00:06:41,140 So how can light can penetrate dust 202 00:06:41,140 --> 00:06:42,460 better than visible light? 203 00:06:42,460 --> 00:06:43,300 Right. 204 00:06:43,300 --> 00:06:45,020 So it gives us a clearer view of the galactic center. 205 00:06:45,020 --> 00:06:45,860 Okay. 206 00:06:45,860 --> 00:06:47,260 And then x-ray telescopes are really good 207 00:06:47,260 --> 00:06:49,380 at observing high energy processes. 208 00:06:49,380 --> 00:06:50,220 Right. 209 00:06:50,220 --> 00:06:51,340 Like those flares we talked about 210 00:06:51,340 --> 00:06:52,900 that happen around black holes. 211 00:06:52,900 --> 00:06:55,440 So it's like we're using all these different senses 212 00:06:55,440 --> 00:06:56,900 to study Sagittarius A. 213 00:06:56,900 --> 00:06:57,740 Yeah. 214 00:06:57,740 --> 00:07:00,300 We're listening with radio waves 215 00:07:00,300 --> 00:07:02,740 peering through the dust with infrared 216 00:07:02,740 --> 00:07:05,660 and then capturing the high energy action with x-rays. 217 00:07:05,660 --> 00:07:06,860 Exactly. 218 00:07:06,860 --> 00:07:08,400 It's incredible how much we can learn 219 00:07:08,400 --> 00:07:09,940 using all these different methods. 220 00:07:09,940 --> 00:07:10,760 Yeah. 221 00:07:10,760 --> 00:07:11,940 And it's not just about observing 222 00:07:11,940 --> 00:07:13,780 the black hole itself either. 223 00:07:13,780 --> 00:07:16,740 Remember those stars that are orbiting Sagittarius A? 224 00:07:16,740 --> 00:07:19,340 You mean the ones we're using as like cosmic speedometers? 225 00:07:19,340 --> 00:07:20,940 Exactly. 226 00:07:20,940 --> 00:07:24,320 By tracking their movements super carefully over time, 227 00:07:24,320 --> 00:07:26,260 astronomers can actually calculate 228 00:07:26,260 --> 00:07:28,740 the mass of Sagittarius A. 229 00:07:28,740 --> 00:07:29,560 Wow. 230 00:07:29,560 --> 00:07:30,860 With incredible precision. 231 00:07:30,860 --> 00:07:31,700 That's amazing. 232 00:07:31,700 --> 00:07:32,520 It really is. 233 00:07:32,520 --> 00:07:34,560 It's like this cosmic ballet. 234 00:07:34,560 --> 00:07:36,940 And the stars are the dancers 235 00:07:36,940 --> 00:07:39,540 and they're revealing the invisible choreographer 236 00:07:39,540 --> 00:07:40,380 at the center. 237 00:07:40,380 --> 00:07:41,460 I love that analogy. 238 00:07:41,460 --> 00:07:42,280 Yeah. 239 00:07:42,280 --> 00:07:43,700 Okay, so we've got these amazing tools 240 00:07:43,700 --> 00:07:46,160 and techniques for studying Sagittarius A. 241 00:07:46,160 --> 00:07:48,260 But what about the big picture questions? 242 00:07:48,260 --> 00:07:49,100 Yeah. 243 00:07:49,100 --> 00:07:50,540 What are some of the mysteries 244 00:07:50,540 --> 00:07:52,620 that are still stumping astronomers? 245 00:07:52,620 --> 00:07:54,140 Well, one of the biggest ones is 246 00:07:54,140 --> 00:07:56,980 why is Sagittarius A so quiet? 247 00:07:56,980 --> 00:07:57,820 Right. 248 00:07:57,820 --> 00:08:00,220 It's like this giant monster that's just, you know, 249 00:08:00,220 --> 00:08:02,940 snacking instead of devouring everything in sight. 250 00:08:02,940 --> 00:08:03,780 Exactly. 251 00:08:03,780 --> 00:08:05,100 So what are some of the theories about why that is? 252 00:08:05,100 --> 00:08:07,300 Well, one possibility is that the magnetic fields 253 00:08:07,300 --> 00:08:10,140 around Sagittarius A are kind of acting like a barrier. 254 00:08:10,140 --> 00:08:10,960 Okay. 255 00:08:10,960 --> 00:08:13,180 Preventing matter from falling indirectly. 256 00:08:13,180 --> 00:08:14,580 So it's like a cosmic traffic cop. 257 00:08:14,580 --> 00:08:15,420 Yeah, exactly. 258 00:08:15,420 --> 00:08:17,500 Correcting traffic away from the black hole's hungry mouth. 259 00:08:17,500 --> 00:08:19,780 Yeah, so it's not that Sagittarius A isn't hungry. 260 00:08:19,780 --> 00:08:22,340 It's just that the food can't reach its plate. 261 00:08:22,340 --> 00:08:23,500 That's a great way to put it. 262 00:08:23,500 --> 00:08:24,620 Thanks. 263 00:08:24,620 --> 00:08:25,780 Are there any other theories? 264 00:08:25,780 --> 00:08:28,500 Yeah, another possibility is that the material 265 00:08:28,500 --> 00:08:31,720 around Sagittarius A is just too spread out 266 00:08:31,720 --> 00:08:34,340 to effectively fuel its growth. 267 00:08:34,340 --> 00:08:35,780 So it's like trying to build a campfire 268 00:08:35,780 --> 00:08:38,820 with just like a few twigs and leaves scattered around. 269 00:08:38,820 --> 00:08:39,660 Exactly. 270 00:08:39,660 --> 00:08:41,020 You need a big pile of fuel to get it going. 271 00:08:41,020 --> 00:08:43,180 Right, it's a supply and demand issue. 272 00:08:43,180 --> 00:08:44,020 Interesting. 273 00:08:44,020 --> 00:08:45,500 Any other ideas? 274 00:08:45,500 --> 00:08:47,900 Yeah, there's also the possibility that Sagittarius A 275 00:08:47,900 --> 00:08:51,140 just goes through cycles of activity, you know, 276 00:08:51,140 --> 00:08:54,660 with periods of intense feeding, 277 00:08:54,660 --> 00:08:57,580 followed by quieter periods of digestion. 278 00:08:57,580 --> 00:09:00,100 So we could just be catching it during a downtime. 279 00:09:00,100 --> 00:09:00,940 Exactly. 280 00:09:00,940 --> 00:09:03,540 Like a cosmic snake that's just swallowed a really big meal. 281 00:09:03,540 --> 00:09:04,380 Exactly. 282 00:09:04,380 --> 00:09:06,140 And who knows, maybe sometime in the future, 283 00:09:06,140 --> 00:09:09,220 it'll wake up with a roar and start devouring matter 284 00:09:09,220 --> 00:09:11,580 and spewing out these huge jets of energy. 285 00:09:11,580 --> 00:09:13,780 Yeah, that would be something to see. 286 00:09:13,780 --> 00:09:15,340 But speaking of mysteries, 287 00:09:15,340 --> 00:09:18,140 what about the origins of Sagittarius A? 288 00:09:18,140 --> 00:09:19,500 Oh yeah. 289 00:09:19,500 --> 00:09:21,560 How did this supermassive black hole 290 00:09:21,560 --> 00:09:23,300 even form in the first place? 291 00:09:23,300 --> 00:09:26,340 Well, that's one of the biggest questions in astrophysics. 292 00:09:26,340 --> 00:09:28,500 And just like most things about black holes, 293 00:09:28,500 --> 00:09:30,040 the answer is still a mystery. 294 00:09:30,040 --> 00:09:30,880 Of course it is. 295 00:09:30,880 --> 00:09:32,980 But there are a few leading theories, 296 00:09:32,980 --> 00:09:35,820 each with their own intriguing possibilities. 297 00:09:35,820 --> 00:09:38,460 Okay, I'm ready for a cosmic history lesson. 298 00:09:38,460 --> 00:09:39,820 Tell me about some of these theories. 299 00:09:39,820 --> 00:09:40,660 All right. 300 00:09:40,660 --> 00:09:44,020 So one of the popular theories is the seed scenario. 301 00:09:44,020 --> 00:09:45,740 The seed scenario, right? 302 00:09:45,740 --> 00:09:48,420 The idea here is that Sagittarius A 303 00:09:48,420 --> 00:09:51,100 started out as a much smaller black hole. 304 00:09:51,100 --> 00:09:51,940 Okay. 305 00:09:51,940 --> 00:09:54,340 Maybe formed from the collapse of a massive star 306 00:09:54,340 --> 00:09:55,860 early in the Milky Way's history. 307 00:09:55,860 --> 00:09:56,700 Okay. 308 00:09:56,700 --> 00:09:58,400 And then over billions of years, 309 00:09:58,400 --> 00:10:01,280 this seed black hole would have grown 310 00:10:01,280 --> 00:10:04,860 by swallowing up gas, dust, and even other black holes. 311 00:10:04,860 --> 00:10:05,700 Okay. 312 00:10:05,700 --> 00:10:06,780 And eventually it would have become 313 00:10:06,780 --> 00:10:08,860 the supermassive black hole we see today. 314 00:10:08,860 --> 00:10:11,220 So like the classic rags to riches story. 315 00:10:11,220 --> 00:10:12,340 Yeah, you could say that. 316 00:10:12,340 --> 00:10:14,140 Starts small and works its way up. 317 00:10:14,140 --> 00:10:15,380 Exactly. 318 00:10:15,380 --> 00:10:16,900 But there's some issues with this theory, right? 319 00:10:16,900 --> 00:10:17,720 Right. 320 00:10:17,720 --> 00:10:19,180 To grow to its current size, 321 00:10:19,180 --> 00:10:21,940 Sagittarius A would have needed a constant supply of fuel. 322 00:10:21,940 --> 00:10:22,780 Yeah. 323 00:10:22,780 --> 00:10:24,280 And it's not really clear if the conditions 324 00:10:24,280 --> 00:10:25,780 in the early universe were right 325 00:10:25,780 --> 00:10:27,420 for that kind of rapid growth. 326 00:10:27,420 --> 00:10:28,820 Right, like trying to figure out 327 00:10:28,820 --> 00:10:32,420 how a little sapling grew into this giant redwood tree. 328 00:10:32,420 --> 00:10:33,260 Exactly. 329 00:10:33,260 --> 00:10:35,180 It's possible, but we're missing some details. 330 00:10:35,180 --> 00:10:36,060 Exactly. 331 00:10:36,060 --> 00:10:38,420 And that's where some of these other theories come in. 332 00:10:38,420 --> 00:10:41,460 Another interesting one is the direct collapse scenario. 333 00:10:41,460 --> 00:10:42,860 The direct collapse scenario. 334 00:10:42,860 --> 00:10:43,680 Yeah. 335 00:10:43,680 --> 00:10:46,300 So in this model, you've got this massive cloud 336 00:10:46,300 --> 00:10:49,860 of gas and dust, millions of times the mass of the sun, 337 00:10:49,860 --> 00:10:53,460 and it collapses directly into a black hole. 338 00:10:53,460 --> 00:10:56,540 It completely skips the whole star formation process. 339 00:10:56,540 --> 00:10:57,380 That's pretty dramatic. 340 00:10:57,380 --> 00:10:58,340 It is. 341 00:10:58,340 --> 00:11:01,900 But wouldn't that create a lot of chaos? 342 00:11:01,900 --> 00:11:02,740 It would. 343 00:11:02,740 --> 00:11:04,660 Would we be able to see evidence of that today? 344 00:11:04,660 --> 00:11:05,940 That's a great question. 345 00:11:05,940 --> 00:11:08,620 And it's one of the big debates about this theory. 346 00:11:08,620 --> 00:11:12,660 The early universe was a crazy place, so it's possible. 347 00:11:12,660 --> 00:11:15,580 But we haven't seen any direct evidence of it happening, 348 00:11:15,580 --> 00:11:17,460 so for now, it's just a theory. 349 00:11:17,460 --> 00:11:18,900 So the jury's still out on that one. 350 00:11:18,900 --> 00:11:19,740 Yeah. 351 00:11:19,740 --> 00:11:21,780 Are there any other possible explanations? 352 00:11:21,780 --> 00:11:24,860 Well, another one, though it's not as popular, 353 00:11:24,860 --> 00:11:27,060 is that Sagittarius A, 354 00:11:27,060 --> 00:11:29,900 formed from a bunch of smaller black holes merging together. 355 00:11:29,900 --> 00:11:34,740 So you can imagine this cosmic mosh pit of black holes 356 00:11:34,740 --> 00:11:38,020 colliding and combining over billions of years. 357 00:11:38,020 --> 00:11:39,460 Cosmic mosh pit. 358 00:11:39,460 --> 00:11:40,300 Yeah. I love it. 359 00:11:40,300 --> 00:11:43,300 Until you get the supermassive monster that we see today. 360 00:11:43,300 --> 00:11:45,540 But wouldn't all that chaos leave behind 361 00:11:45,540 --> 00:11:47,020 some kind of evidence? 362 00:11:47,020 --> 00:11:48,260 You'd think so, right? 363 00:11:48,260 --> 00:11:49,100 Yeah. 364 00:11:49,100 --> 00:11:51,140 And we do see evidence of black hole mergers 365 00:11:51,140 --> 00:11:52,380 in other galaxies. 366 00:11:52,380 --> 00:11:53,220 Okay. 367 00:11:53,220 --> 00:11:55,740 But it's not clear if that process could explain something 368 00:11:55,740 --> 00:11:58,340 as massive as Sagittarius A. 369 00:11:58,340 --> 00:11:59,180 Right. 370 00:11:59,180 --> 00:12:00,900 The galactic center is pretty crowded, 371 00:12:00,900 --> 00:12:03,820 and it's possible that all the stars and other objects 372 00:12:03,820 --> 00:12:07,140 could have disrupted that whole merger process. 373 00:12:07,140 --> 00:12:08,620 So it seems like we're still trying to figure out 374 00:12:08,620 --> 00:12:10,860 exactly how Sagittarius A came to be. 375 00:12:10,860 --> 00:12:11,740 We are. 376 00:12:11,740 --> 00:12:13,220 But one thing's for sure, 377 00:12:13,220 --> 00:12:15,620 it's had a huge impact on shaping the Milky Way. 378 00:12:15,620 --> 00:12:16,700 Absolutely. 379 00:12:16,700 --> 00:12:18,540 As we learn more about Sagittarius A, 380 00:12:18,540 --> 00:12:20,300 we're not just learning about one object, 381 00:12:20,300 --> 00:12:22,300 we're learning about how galaxies evolve, 382 00:12:22,300 --> 00:12:23,580 the nature of gravity, 383 00:12:23,580 --> 00:12:26,220 and maybe even the fundamental laws of physics. 384 00:12:26,220 --> 00:12:28,980 It's amazing that something so mysterious 385 00:12:28,980 --> 00:12:31,500 can teach us so much about the universe. 386 00:12:31,500 --> 00:12:32,340 It is. 387 00:12:32,340 --> 00:12:35,420 And that journey of discovery is full of incredible wonders 388 00:12:35,420 --> 00:12:36,940 and tantalizing mysteries. 389 00:12:36,940 --> 00:12:38,700 And speaking of mysteries, 390 00:12:38,700 --> 00:12:41,180 I think it's time we look to the future. 391 00:12:41,180 --> 00:12:43,500 What are some of the upcoming advancements 392 00:12:43,500 --> 00:12:46,740 that could revolutionize our understanding of Sagittarius A? 393 00:12:46,740 --> 00:12:48,260 Well, one of the most exciting things 394 00:12:48,260 --> 00:12:50,220 is the next generation of telescopes. 395 00:12:50,220 --> 00:12:51,060 Oh yeah. 396 00:12:51,060 --> 00:12:51,900 Yeah. 397 00:12:51,900 --> 00:12:54,980 They're gonna be so much more powerful and sensitive 398 00:12:54,980 --> 00:12:56,980 than anything we have today. 399 00:12:56,980 --> 00:12:58,940 So we'll be able to see even deeper 400 00:12:58,940 --> 00:13:00,700 into the heart of our galaxy 401 00:13:00,700 --> 00:13:04,180 and get even more precise data about Sagittarius A. 402 00:13:04,180 --> 00:13:07,140 It's like getting a major upgrade to our cosmic lenses. 403 00:13:07,140 --> 00:13:07,980 Exactly. 404 00:13:07,980 --> 00:13:09,380 What are some of these telescopes 405 00:13:09,380 --> 00:13:11,220 that astronomers are really excited about? 406 00:13:11,220 --> 00:13:12,780 Well, one that I'm really excited about 407 00:13:12,780 --> 00:13:16,500 is the Extremely Large Telescope, or ELT. 408 00:13:16,500 --> 00:13:17,340 The ELT. 409 00:13:17,340 --> 00:13:18,180 Yeah. 410 00:13:18,180 --> 00:13:19,860 It's being built right now in Chile. 411 00:13:19,860 --> 00:13:20,700 Wow. 412 00:13:20,700 --> 00:13:22,860 And it's gonna have this massive mirror 413 00:13:22,860 --> 00:13:25,020 over 39 meters in diameter. 414 00:13:25,020 --> 00:13:26,580 That's like the size of a football field. 415 00:13:26,580 --> 00:13:27,420 It is. 416 00:13:27,420 --> 00:13:28,540 It'll be the biggest optical 417 00:13:28,540 --> 00:13:30,420 near infrared telescope in the world. 418 00:13:30,420 --> 00:13:31,260 That's incredible. 419 00:13:31,260 --> 00:13:32,100 Yeah. 420 00:13:32,100 --> 00:13:34,340 What will that kind of power allow us to see? 421 00:13:34,340 --> 00:13:37,140 Well, it's gonna be able to resolve individual stars. 422 00:13:37,140 --> 00:13:37,980 Wow. 423 00:13:37,980 --> 00:13:40,780 In the galactic center, even though it's super crowded. 424 00:13:40,780 --> 00:13:41,620 Right. 425 00:13:41,620 --> 00:13:44,660 So it's gonna be like having a front row seat 426 00:13:44,660 --> 00:13:45,980 to the Cosmic Ballet. 427 00:13:45,980 --> 00:13:46,820 I love it. 428 00:13:46,820 --> 00:13:48,580 Happening around the Sagittarius A. 429 00:13:48,580 --> 00:13:49,860 What about those other wavelengths 430 00:13:49,860 --> 00:13:51,900 we've been talking about, like radio and X-ray? 431 00:13:51,900 --> 00:13:52,740 Oh yeah. 432 00:13:52,740 --> 00:13:54,700 Are there any new telescopes coming online 433 00:13:54,700 --> 00:13:56,820 that will give us a better view with those? 434 00:13:56,820 --> 00:13:57,700 Yeah, definitely. 435 00:13:57,700 --> 00:14:01,620 So in radio astronomy, we have the Square Kilometer Array. 436 00:14:01,620 --> 00:14:02,460 Okay. 437 00:14:02,460 --> 00:14:03,300 Or SKA. 438 00:14:03,300 --> 00:14:04,220 The SKA, okay. 439 00:14:04,220 --> 00:14:06,340 It's gonna be the largest and most sensitive 440 00:14:06,340 --> 00:14:07,820 radio telescope ever built. 441 00:14:07,820 --> 00:14:08,660 Really? 442 00:14:08,660 --> 00:14:10,540 Yeah, it's spread out across multiple continents. 443 00:14:10,540 --> 00:14:11,380 Wow. 444 00:14:11,380 --> 00:14:14,100 And it combines signals from thousands of antennas 445 00:14:14,100 --> 00:14:17,900 to create this virtual telescope with incredible resolution. 446 00:14:17,900 --> 00:14:19,340 It's like a truly global effort. 447 00:14:19,340 --> 00:14:20,180 It is. 448 00:14:20,180 --> 00:14:21,020 To explore the universe. 449 00:14:21,020 --> 00:14:21,860 Yeah. 450 00:14:21,860 --> 00:14:24,020 So what kind of insights are they hoping to get from the SKA? 451 00:14:24,020 --> 00:14:27,180 Well, it's gonna be able to study those radio emissions 452 00:14:27,180 --> 00:14:30,260 from Sagittarius A in such detail 453 00:14:30,260 --> 00:14:32,260 that we'll see the structure and dynamics 454 00:14:32,260 --> 00:14:34,060 of that gas swirling around it. 455 00:14:34,060 --> 00:14:34,900 Wow. 456 00:14:34,900 --> 00:14:38,420 And it'll also be able to probe those magnetic fields 457 00:14:38,420 --> 00:14:39,980 threading through the galactic center. 458 00:14:39,980 --> 00:14:41,100 Which we talked about earlier. 459 00:14:41,100 --> 00:14:41,940 Yes. 460 00:14:41,940 --> 00:14:43,620 Yeah, it could be regulating its activity. 461 00:14:43,620 --> 00:14:45,020 Exactly, exactly. 462 00:14:45,020 --> 00:14:47,100 So the SKA will be like a cosmic detective 463 00:14:47,100 --> 00:14:49,620 trying to figure out why Sagittarius A is so quiet. 464 00:14:49,620 --> 00:14:50,860 Exactly. 465 00:14:50,860 --> 00:14:52,460 Okay, what about X-ray telescopes? 466 00:14:52,460 --> 00:14:54,580 Any exciting new missions in development? 467 00:14:54,580 --> 00:14:55,740 Yeah, definitely. 468 00:14:55,740 --> 00:14:59,900 So one that's coming up is the Athena X-ray Observatory. 469 00:14:59,900 --> 00:15:00,740 Athena? 470 00:15:00,740 --> 00:15:01,560 Yeah. Okay. 471 00:15:01,560 --> 00:15:03,780 It's a collaboration between the European Space Agency 472 00:15:03,780 --> 00:15:05,100 and NASA. 473 00:15:05,100 --> 00:15:05,940 Oh wow. 474 00:15:05,940 --> 00:15:07,220 And it's going to be the largest 475 00:15:07,220 --> 00:15:10,700 and most sensitive X-ray telescope ever launched. 476 00:15:10,700 --> 00:15:11,540 Really? 477 00:15:11,540 --> 00:15:12,820 Yeah, it's gonna be amazing 478 00:15:12,820 --> 00:15:15,540 for studying that superheated gas 479 00:15:15,540 --> 00:15:18,260 and energetic particles around Sagittarius A. 480 00:15:18,260 --> 00:15:19,980 So we're sending a high powered microscope 481 00:15:19,980 --> 00:15:21,020 to the galactic center. 482 00:15:21,020 --> 00:15:21,860 We are. 483 00:15:21,860 --> 00:15:24,180 To look at all the tiny details around the black hole. 484 00:15:24,180 --> 00:15:25,420 Exactly. 485 00:15:25,420 --> 00:15:26,260 That's amazing. 486 00:15:26,260 --> 00:15:27,080 It is. 487 00:15:27,080 --> 00:15:29,540 With all these new telescopes coming online, 488 00:15:29,540 --> 00:15:33,020 astronomers are gonna have so much data to analyze. 489 00:15:33,020 --> 00:15:33,860 Yeah, they are. 490 00:15:33,860 --> 00:15:35,180 How are they gonna make sense of it all? 491 00:15:35,180 --> 00:15:36,980 Well, analyzing all that data 492 00:15:36,980 --> 00:15:40,140 is gonna require some pretty sophisticated tools 493 00:15:40,140 --> 00:15:41,820 and modeling techniques. 494 00:15:41,820 --> 00:15:45,020 But the good news is that the field of astroinformatics. 495 00:15:45,020 --> 00:15:46,980 Yeah, it's basically using computers 496 00:15:46,980 --> 00:15:49,220 to analyze astronomical data. 497 00:15:49,220 --> 00:15:51,940 That field is growing really quickly. 498 00:15:51,940 --> 00:15:52,780 Okay. 499 00:15:52,780 --> 00:15:55,860 And they're coming up with new algorithms and software 500 00:15:55,860 --> 00:16:00,060 to help astronomers understand these huge cosmic data sets. 501 00:16:00,060 --> 00:16:02,540 It's like building a cosmic supercomputer 502 00:16:02,540 --> 00:16:04,420 to decode the secrets of the universe. 503 00:16:04,420 --> 00:16:05,260 It is. 504 00:16:05,260 --> 00:16:07,980 But even with all this incredible technology, 505 00:16:07,980 --> 00:16:10,620 it's important to remember the human element of all of this. 506 00:16:10,620 --> 00:16:11,460 Absolutely. 507 00:16:11,460 --> 00:16:14,580 What role will astronomers play in this new era? 508 00:16:14,580 --> 00:16:16,180 In this new era of discovery? 509 00:16:16,180 --> 00:16:18,300 Well, human ingenuity and creativity 510 00:16:18,300 --> 00:16:20,020 are gonna be more important than ever before. 511 00:16:20,020 --> 00:16:20,860 Right. 512 00:16:20,860 --> 00:16:22,100 Technology is just a tool. 513 00:16:22,100 --> 00:16:22,940 Yeah. 514 00:16:22,940 --> 00:16:23,780 It gives us data. 515 00:16:23,780 --> 00:16:24,620 Yeah. 516 00:16:24,620 --> 00:16:26,780 But it's up to astronomers to ask the right questions, 517 00:16:26,780 --> 00:16:28,180 design the experiments, 518 00:16:28,180 --> 00:16:29,740 and interpret the results. 519 00:16:29,740 --> 00:16:32,860 It's a collaboration between human intellect 520 00:16:32,860 --> 00:16:34,100 and machine power. 521 00:16:34,100 --> 00:16:36,140 Like a beautiful cosmic duet, 522 00:16:36,140 --> 00:16:39,420 harmonizing to create this symphony of understanding. 523 00:16:39,420 --> 00:16:40,580 I like that. 524 00:16:40,580 --> 00:16:43,380 So with all these advancements on the horizon, 525 00:16:43,380 --> 00:16:46,740 what are astronomers most excited to learn 526 00:16:46,740 --> 00:16:48,500 about Sagittarius A? 527 00:16:48,500 --> 00:16:52,180 Well, one of the big ones is understanding how it feeds. 528 00:16:52,180 --> 00:16:53,020 Yeah. 529 00:16:53,020 --> 00:16:55,660 How does matter actually fall into Sagittarius A? 530 00:16:55,660 --> 00:16:58,300 What are the mechanisms that control its appetite? 531 00:16:58,300 --> 00:16:59,140 Right. 532 00:16:59,140 --> 00:17:00,500 And why is it so much quieter 533 00:17:00,500 --> 00:17:03,020 compared to other supermassive black holes? 534 00:17:03,020 --> 00:17:05,540 It's like trying to figure out the secrets of a picky eater. 535 00:17:05,540 --> 00:17:06,380 Yeah. 536 00:17:06,380 --> 00:17:07,660 Or maybe one that's always on a diet. 537 00:17:07,660 --> 00:17:08,620 Exactly. 538 00:17:08,620 --> 00:17:10,820 We also wanna know if Sagittarius A 539 00:17:10,820 --> 00:17:14,140 could ever have those powerful jets of energy. 540 00:17:14,140 --> 00:17:14,980 Oh, yeah. 541 00:17:14,980 --> 00:17:16,100 That we see in other black holes. 542 00:17:16,100 --> 00:17:16,940 Yeah. 543 00:17:16,940 --> 00:17:19,060 It's quiet now, but could it wake up someday? 544 00:17:19,060 --> 00:17:19,900 It could. 545 00:17:19,900 --> 00:17:21,500 And spew out jets that could change 546 00:17:21,500 --> 00:17:22,780 the whole galactic center. 547 00:17:22,780 --> 00:17:23,620 Exactly. 548 00:17:23,620 --> 00:17:24,780 It's kinda like living next to a volcano 549 00:17:24,780 --> 00:17:26,620 and wondering if and when it's gonna erupt. 550 00:17:26,620 --> 00:17:27,540 Yeah, it is. 551 00:17:27,540 --> 00:17:29,420 But beyond its activity, 552 00:17:29,420 --> 00:17:31,460 what are some other fundamental mysteries 553 00:17:31,460 --> 00:17:33,340 that scientists wanna solve? 554 00:17:33,340 --> 00:17:35,620 Well, maybe the most profound question is, 555 00:17:35,620 --> 00:17:37,900 what's the nature of the singularity itself? 556 00:17:37,900 --> 00:17:38,740 The singularity. 557 00:17:38,740 --> 00:17:41,580 Yeah, what's at the very heart of this black hole? 558 00:17:41,580 --> 00:17:42,420 Right. 559 00:17:42,420 --> 00:17:44,620 Is it really a point of infinite density? 560 00:17:44,620 --> 00:17:45,460 Yeah. 561 00:17:45,460 --> 00:17:46,300 Or is it something else, 562 00:17:46,300 --> 00:17:48,020 something we can't even imagine yet? 563 00:17:48,020 --> 00:17:49,940 It's like staring into the abyss. 564 00:17:49,940 --> 00:17:50,780 It is. 565 00:17:50,780 --> 00:17:51,780 Trying to understand something 566 00:17:51,780 --> 00:17:54,060 that's completely beyond our comprehension. 567 00:17:54,060 --> 00:17:54,900 Yeah. 568 00:17:54,900 --> 00:17:56,340 But even with all these mysteries 569 00:17:56,340 --> 00:17:58,260 that we still haven't solved, 570 00:17:58,260 --> 00:17:59,780 one thing's clear. 571 00:17:59,780 --> 00:18:02,860 Sagittarius A is just this incredible source 572 00:18:02,860 --> 00:18:04,260 of scientific discovery. 573 00:18:04,260 --> 00:18:05,100 Absolutely. 574 00:18:05,100 --> 00:18:07,500 It reminds us how much we still don't know 575 00:18:07,500 --> 00:18:08,380 about the universe. 576 00:18:08,380 --> 00:18:09,220 Right. 577 00:18:09,220 --> 00:18:10,620 And that the quest to understand it 578 00:18:10,620 --> 00:18:12,540 is full of wonder and excitement. 579 00:18:12,540 --> 00:18:13,500 Exactly. 580 00:18:13,500 --> 00:18:15,900 And it pushes us to the very limits of human knowledge. 581 00:18:15,900 --> 00:18:17,340 It does. 582 00:18:17,340 --> 00:18:18,820 Well, that brings our deep dive 583 00:18:18,820 --> 00:18:21,380 into the mysteries of Sagittarius A to a close. 584 00:18:21,380 --> 00:18:22,300 Yeah. 585 00:18:22,300 --> 00:18:24,540 We've traveled to the heart of our galaxy, 586 00:18:24,540 --> 00:18:27,900 explored the mind-boggling nature of black holes, 587 00:18:27,900 --> 00:18:30,420 and looked ahead at the future of cosmic exploration. 588 00:18:30,420 --> 00:18:31,300 We have. 589 00:18:31,300 --> 00:18:33,380 I hope you've enjoyed this adventure as much as we have. 590 00:18:33,380 --> 00:18:34,300 I know I have. 591 00:18:34,300 --> 00:18:35,820 It's been a fascinating journey. 592 00:18:35,820 --> 00:18:39,260 If you're as fascinated by the cosmos as we are, 593 00:18:39,260 --> 00:18:41,900 be sure to follow and subscribe to Cosmos in a Pot. 594 00:18:41,900 --> 00:18:44,260 For more explorations of the universe, 595 00:18:45,420 --> 00:18:47,220 and don't forget to check out our YouTube channel. 596 00:18:47,220 --> 00:18:48,060 Please. 597 00:18:48,060 --> 00:18:49,860 For even more amazing content. 598 00:18:49,860 --> 00:19:06,860 Until next time, keep looking up and keep wondering.