1 00:00:00,000 --> 00:00:03,120 Welcome back to Cosmos and a Pod Space and Astronomy Series. 2 00:00:03,120 --> 00:00:04,240 Episode 12. 3 00:00:04,240 --> 00:00:05,320 Episode 12. 4 00:00:05,320 --> 00:00:06,080 Wow. 5 00:00:06,080 --> 00:00:09,160 Today, we're taking a deep dive into something truly awe 6 00:00:09,160 --> 00:00:10,000 inspiring. 7 00:00:10,000 --> 00:00:10,600 Yeah. 8 00:00:10,600 --> 00:00:12,440 How planets form. 9 00:00:12,440 --> 00:00:13,440 It's amazing. 10 00:00:13,440 --> 00:00:14,160 You know, it's one of those things 11 00:00:14,160 --> 00:00:15,240 we often take for granted. 12 00:00:15,240 --> 00:00:15,640 Yeah. 13 00:00:15,640 --> 00:00:17,480 We see the planets in our solar system. 14 00:00:17,480 --> 00:00:18,800 Right. 15 00:00:18,800 --> 00:00:21,520 But have you ever stopped to consider 16 00:00:21,520 --> 00:00:23,000 the incredible journey. 17 00:00:23,000 --> 00:00:23,920 Oh, yeah. 18 00:00:23,920 --> 00:00:25,400 That brought them into existence. 19 00:00:25,400 --> 00:00:26,120 Absolutely. 20 00:00:26,120 --> 00:00:29,600 From microscopic dust to entire worlds. 21 00:00:29,600 --> 00:00:30,640 I know. 22 00:00:30,640 --> 00:00:33,840 It's a process that spans billions of years. 23 00:00:33,840 --> 00:00:34,680 Billions. 24 00:00:34,680 --> 00:00:37,720 And involve a mind boggling interplay of forces. 25 00:00:37,720 --> 00:00:39,560 It is happening all the time too. 26 00:00:39,560 --> 00:00:40,200 All the time. 27 00:00:40,200 --> 00:00:42,120 It's not just something that happened in the past. 28 00:00:42,120 --> 00:00:42,640 Right. 29 00:00:42,640 --> 00:00:44,560 It's happening right now as we speak. 30 00:00:44,560 --> 00:00:45,400 That's incredible. 31 00:00:45,400 --> 00:00:45,920 Yeah. 32 00:00:45,920 --> 00:00:48,560 So we've all seen those beautiful artist renderings. 33 00:00:48,560 --> 00:00:49,640 I love those. 34 00:00:49,640 --> 00:00:53,320 The swirling dust clouds giving birth to stars and planets. 35 00:00:53,320 --> 00:00:55,280 It's just, it captures the imagination. 36 00:00:55,280 --> 00:00:55,840 It does. 37 00:00:55,840 --> 00:00:56,360 Yeah. 38 00:00:56,360 --> 00:00:58,640 But where does the actual story begin? 39 00:00:58,640 --> 00:01:03,000 What's the raw material for these celestial masterpieces? 40 00:01:03,000 --> 00:01:06,680 Well, it all starts with what we call protoplanetary disks. 41 00:01:06,680 --> 00:01:08,000 Protoplanetary disks. 42 00:01:08,000 --> 00:01:08,480 Yeah. 43 00:01:08,480 --> 00:01:11,320 Imagine a vast cloud of gas and dust. 44 00:01:11,320 --> 00:01:11,800 OK. 45 00:01:11,800 --> 00:01:14,480 Mostly leftover from the birth of a young star. 46 00:01:14,480 --> 00:01:15,080 OK. 47 00:01:15,080 --> 00:01:17,480 Gravity pulls this material inward, 48 00:01:17,480 --> 00:01:20,680 but it doesn't just collapse directly onto the star. 49 00:01:20,680 --> 00:01:21,120 Right. 50 00:01:21,120 --> 00:01:25,600 Instead, due to the conservation of angular momentum. 51 00:01:25,600 --> 00:01:27,040 You know that principle of physics 52 00:01:27,040 --> 00:01:29,480 that keeps a spinning figure skater spinning faster. 53 00:01:29,480 --> 00:01:30,000 Oh, yeah. 54 00:01:30,000 --> 00:01:31,160 As they pull their arms in. 55 00:01:31,160 --> 00:01:31,760 Right. 56 00:01:31,760 --> 00:01:35,440 This material starts to rotate and flatten out. 57 00:01:35,440 --> 00:01:35,960 OK. 58 00:01:35,960 --> 00:01:37,560 Into a disk shape. 59 00:01:37,560 --> 00:01:39,600 So it's like a cosmic pottery wheel. 60 00:01:39,600 --> 00:01:40,120 Exactly. 61 00:01:40,120 --> 00:01:42,320 Shaping this raw material into a flat disk. 62 00:01:42,320 --> 00:01:42,840 Yeah. 63 00:01:42,840 --> 00:01:45,120 And this is where planets begin to emerge. 64 00:01:45,120 --> 00:01:45,840 Exactly. 65 00:01:45,840 --> 00:01:47,640 But it's not just a uniform disk. 66 00:01:47,640 --> 00:01:48,120 OK. 67 00:01:48,120 --> 00:01:49,680 The temperature varies dramatically 68 00:01:49,680 --> 00:01:51,600 depending on the distance from the star. 69 00:01:51,600 --> 00:01:52,240 Oh, I see. 70 00:01:52,240 --> 00:01:54,200 Close to the star, it's incredibly hot. 71 00:01:54,200 --> 00:01:54,720 Right. 72 00:01:54,720 --> 00:01:56,760 While further out, temperatures plunge 73 00:01:56,760 --> 00:01:58,640 to freezing and beyond. 74 00:01:58,640 --> 00:01:59,280 OK. 75 00:01:59,280 --> 00:02:01,920 This temperature gradient plays a crucial role. 76 00:02:01,920 --> 00:02:02,280 Wow. 77 00:02:02,280 --> 00:02:04,920 In determining what types of planets can form. 78 00:02:04,920 --> 00:02:06,760 So different regions of the disk are 79 00:02:06,760 --> 00:02:08,760 suited for different types of planets. 80 00:02:08,760 --> 00:02:10,160 It's like cosmic zoning. 81 00:02:10,160 --> 00:02:11,000 Cosmic zoning. 82 00:02:11,000 --> 00:02:11,520 I like that. 83 00:02:11,520 --> 00:02:11,880 Yeah. 84 00:02:11,880 --> 00:02:14,240 Tell me more about how this temperature gradient affects 85 00:02:14,240 --> 00:02:15,440 planet formation. 86 00:02:15,440 --> 00:02:15,720 OK. 87 00:02:15,720 --> 00:02:16,800 So think about it this way. 88 00:02:16,800 --> 00:02:17,320 All right. 89 00:02:17,320 --> 00:02:20,840 In the inner region of the disk, close to the young blazing 90 00:02:20,840 --> 00:02:25,720 star, only heavy elements like metals and rock 91 00:02:25,720 --> 00:02:28,320 can withstand the intense heat. 92 00:02:28,320 --> 00:02:29,160 Oh. 93 00:02:29,160 --> 00:02:32,680 These are the building blocks for rocky terrestrial planets 94 00:02:32,680 --> 00:02:34,000 like Earth and Mars. 95 00:02:34,000 --> 00:02:37,760 So our planet's fiery beginnings play the key role 96 00:02:37,760 --> 00:02:39,400 in shaping its rocky nature. 97 00:02:39,400 --> 00:02:40,080 Absolutely. 98 00:02:40,080 --> 00:02:42,200 What about the outer regions of the disk? 99 00:02:42,200 --> 00:02:42,720 Yes. 100 00:02:42,720 --> 00:02:45,720 Those are where the gas giants like Jupiter and Saturn reside. 101 00:02:45,720 --> 00:02:46,240 Right. 102 00:02:46,240 --> 00:02:47,120 Yes, right. 103 00:02:47,120 --> 00:02:49,280 As you move further away from the star, 104 00:02:49,280 --> 00:02:51,120 past what we call the frost line. 105 00:02:51,120 --> 00:02:51,880 The frost line. 106 00:02:51,880 --> 00:02:52,280 Yeah. 107 00:02:52,280 --> 00:02:52,800 OK. 108 00:02:52,800 --> 00:02:54,400 The temperature drops significantly. 109 00:02:54,400 --> 00:02:54,920 OK. 110 00:02:54,920 --> 00:02:57,960 It becomes cold enough for volatile compounds 111 00:02:57,960 --> 00:03:02,440 like water, methane, and ammonia to freeze into solid ice. 112 00:03:02,440 --> 00:03:03,360 The frost line. 113 00:03:03,360 --> 00:03:04,960 So it's like a crucial boundary. 114 00:03:04,960 --> 00:03:05,240 Yeah. 115 00:03:05,240 --> 00:03:06,520 Think of it as a dividing line. 116 00:03:06,520 --> 00:03:07,600 A dividing line, OK. 117 00:03:07,600 --> 00:03:10,920 Between the realm of rocky planets 118 00:03:10,920 --> 00:03:12,440 and the realm of gas giants. 119 00:03:12,440 --> 00:03:12,960 OK. 120 00:03:12,960 --> 00:03:14,320 So inside the frost line. 121 00:03:14,320 --> 00:03:14,720 Yeah. 122 00:03:14,720 --> 00:03:15,440 Rocky planets. 123 00:03:15,440 --> 00:03:16,920 Rocky planets and outside. 124 00:03:16,920 --> 00:03:17,520 Gas giants. 125 00:03:17,520 --> 00:03:19,040 Gas giants and ice giants. 126 00:03:19,040 --> 00:03:21,120 It makes you wonder how different our solar system 127 00:03:21,120 --> 00:03:23,920 would be if that frost line were located somewhere else. 128 00:03:23,920 --> 00:03:25,080 Absolutely, yeah. 129 00:03:25,080 --> 00:03:26,120 But let's rewind a bit. 130 00:03:26,120 --> 00:03:26,440 OK. 131 00:03:26,440 --> 00:03:28,040 We've got these temperature gradients, 132 00:03:28,040 --> 00:03:29,600 these different regions in the disk. 133 00:03:29,600 --> 00:03:30,120 Yeah. 134 00:03:30,120 --> 00:03:35,680 But how do we go from tiny dust particles to actual planets? 135 00:03:35,680 --> 00:03:36,360 Yeah. 136 00:03:36,360 --> 00:03:37,560 It's a giant leap. 137 00:03:37,560 --> 00:03:40,680 It is, but it's a journey that happens step by step. 138 00:03:40,680 --> 00:03:41,160 OK. 139 00:03:41,160 --> 00:03:44,000 It all begins with those tiny dust grains. 140 00:03:44,000 --> 00:03:44,560 All right. 141 00:03:44,560 --> 00:03:49,600 Just specks of elements like silicon, carbon, and iron. 142 00:03:49,600 --> 00:03:49,960 OK. 143 00:03:49,960 --> 00:03:52,920 They're constantly colliding with each other within the disk. 144 00:03:52,920 --> 00:03:54,360 And sometimes they stick together. 145 00:03:54,360 --> 00:03:57,240 So it's like a slow and steady cosmic buildup. 146 00:03:57,240 --> 00:03:57,720 Exactly. 147 00:03:57,720 --> 00:04:00,480 Tiny bits of matter gradually coming together. 148 00:04:00,480 --> 00:04:04,280 At first, electrostatic forces help these dust grains 149 00:04:04,280 --> 00:04:05,320 cling to each other. 150 00:04:05,320 --> 00:04:05,840 OK. 151 00:04:05,840 --> 00:04:10,280 But as they grow larger, their own gravity starts to take over. 152 00:04:10,280 --> 00:04:11,960 Attracting more and more material. 153 00:04:11,960 --> 00:04:12,440 Right. 154 00:04:12,440 --> 00:04:16,400 Eventually, these dust bunnies, we call them pebbles at this stage. 155 00:04:16,400 --> 00:04:17,240 Pebbles? 156 00:04:17,240 --> 00:04:17,640 Yeah. 157 00:04:17,640 --> 00:04:18,140 OK. 158 00:04:18,140 --> 00:04:21,440 Grow into larger clumps known as planetesimals. 159 00:04:21,440 --> 00:04:22,200 Planetesimals. 160 00:04:22,200 --> 00:04:22,720 Yes. 161 00:04:22,720 --> 00:04:25,360 Which can range in size from kilometers to hundreds 162 00:04:25,360 --> 00:04:26,320 of kilometers across. 163 00:04:26,320 --> 00:04:29,680 So it's like they're starting to resemble something we might 164 00:04:29,680 --> 00:04:31,640 recognize as a celestial body. 165 00:04:31,640 --> 00:04:32,600 Yeah, they are. 166 00:04:32,600 --> 00:04:33,080 Finally. 167 00:04:33,080 --> 00:04:35,000 But things are still pretty chaotic 168 00:04:35,000 --> 00:04:36,720 in the protoplanetary disk. 169 00:04:36,720 --> 00:04:37,220 OK. 170 00:04:37,220 --> 00:04:39,600 Imagine a cosmic demolition derby. 171 00:04:39,600 --> 00:04:40,100 Wow. 172 00:04:40,100 --> 00:04:42,240 With these planetesimals constantly 173 00:04:42,240 --> 00:04:43,520 crashing into each other. 174 00:04:43,520 --> 00:04:44,160 Oh, wow. 175 00:04:44,160 --> 00:04:47,320 Some collide and shatter into smaller pieces, 176 00:04:47,320 --> 00:04:49,920 while others merge together and grow larger. 177 00:04:49,920 --> 00:04:52,640 So it's like a game of cosmic bumper cars. 178 00:04:52,640 --> 00:04:53,140 It is. 179 00:04:53,140 --> 00:04:55,320 With only the strongest surviving. 180 00:04:55,320 --> 00:04:56,640 Yeah, you could do that. 181 00:04:56,640 --> 00:04:59,520 And it's fascinating to think about this early period 182 00:04:59,520 --> 00:05:01,440 of intense activity. 183 00:05:01,440 --> 00:05:01,940 Yeah. 184 00:05:01,940 --> 00:05:04,000 And how it shaped the planets we see today. 185 00:05:04,000 --> 00:05:04,800 Absolutely. 186 00:05:04,800 --> 00:05:06,800 So what happens to the planetesimals 187 00:05:06,800 --> 00:05:09,720 that manage to survive this chaotic phase? 188 00:05:09,720 --> 00:05:12,440 The survivors of this cosmic demolition derby. 189 00:05:12,440 --> 00:05:12,960 Right. 190 00:05:12,960 --> 00:05:15,520 The ones that manage to pull through and keep growing 191 00:05:15,520 --> 00:05:17,640 evolve into what we call protoplanets. 192 00:05:17,640 --> 00:05:17,920 Yeah. 193 00:05:17,920 --> 00:05:19,160 So these protoplanets, they're kind 194 00:05:19,160 --> 00:05:20,680 of like the seeds of planets. 195 00:05:20,680 --> 00:05:21,180 Right. 196 00:05:21,180 --> 00:05:25,440 Almost planets still clearing a path and gathering material. 197 00:05:25,440 --> 00:05:25,960 Exactly. 198 00:05:25,960 --> 00:05:27,960 It makes you wonder if things ever settle down 199 00:05:27,960 --> 00:05:29,400 in a planetary system. 200 00:05:29,400 --> 00:05:31,360 Well, that's where we get to a concept called 201 00:05:31,360 --> 00:05:32,760 planetary migration. 202 00:05:32,760 --> 00:05:34,080 Planetary migration. 203 00:05:34,080 --> 00:05:34,580 Yeah. 204 00:05:34,580 --> 00:05:35,320 OK. 205 00:05:35,320 --> 00:05:37,240 That throws a wrench into the idea 206 00:05:37,240 --> 00:05:39,320 of a neatly ordered solar system. 207 00:05:39,320 --> 00:05:40,040 It does. 208 00:05:40,040 --> 00:05:43,960 What could possibly cause a planet to just up and relocate? 209 00:05:43,960 --> 00:05:45,040 It's all about gravity. 210 00:05:45,040 --> 00:05:45,640 Gravity. 211 00:05:45,640 --> 00:05:48,920 Planets exert a gravitational pull on each other. 212 00:05:48,920 --> 00:05:50,960 And that can lead to some complex interactions. 213 00:05:50,960 --> 00:05:51,640 Oh, OK. 214 00:05:51,640 --> 00:05:53,280 Imagine a cosmic dance. 215 00:05:53,280 --> 00:05:53,880 I like that. 216 00:05:53,880 --> 00:05:56,840 Where the gravitational forces from other planets, 217 00:05:56,840 --> 00:06:00,280 or even the remaining gas and dust in the disk, 218 00:06:00,280 --> 00:06:02,840 can nudge a planet out of its original orbit. 219 00:06:02,840 --> 00:06:04,760 So it's a cosmic game of tug of war. 220 00:06:04,760 --> 00:06:05,360 Yeah. 221 00:06:05,360 --> 00:06:06,760 With gravity as the rope. 222 00:06:06,760 --> 00:06:07,680 Pretty much. 223 00:06:07,680 --> 00:06:11,240 And these gravitational tugs can cause a planet 224 00:06:11,240 --> 00:06:15,180 to migrate either inward or outward precisely. 225 00:06:15,180 --> 00:06:17,840 And that migration can have a dramatic impact 226 00:06:17,840 --> 00:06:19,760 on the structure of a planetary system. 227 00:06:19,760 --> 00:06:20,460 Wow. 228 00:06:20,460 --> 00:06:22,840 Some planets might end up closer to their star, 229 00:06:22,840 --> 00:06:24,800 while others might drift further out. 230 00:06:24,800 --> 00:06:25,440 OK. 231 00:06:25,440 --> 00:06:27,360 It can even lead to planets being 232 00:06:27,360 --> 00:06:29,480 ejected from the system entirely. 233 00:06:29,480 --> 00:06:30,000 Wow. 234 00:06:30,000 --> 00:06:31,600 That completely changes the picture 235 00:06:31,600 --> 00:06:33,800 of a static, unchanging solar system. 236 00:06:33,800 --> 00:06:34,520 It does. 237 00:06:34,520 --> 00:06:37,300 It's more like a dynamic, evolving environment 238 00:06:37,300 --> 00:06:39,920 with planets shifting positions over millions of years. 239 00:06:39,920 --> 00:06:40,500 Absolutely. 240 00:06:40,500 --> 00:06:42,400 That's a much better way to think about it. 241 00:06:42,400 --> 00:06:45,200 Are there any examples of this migration 242 00:06:45,200 --> 00:06:46,840 in our own solar system? 243 00:06:46,840 --> 00:06:49,200 There's a good chance our very own Jupiter 244 00:06:49,200 --> 00:06:51,520 might have undergone a period of migration 245 00:06:51,520 --> 00:06:52,680 early in its history. 246 00:06:52,680 --> 00:06:53,480 Jupiter on the move? 247 00:06:53,480 --> 00:06:53,980 Yeah. 248 00:06:53,980 --> 00:06:56,720 Some models suggest it might have formed further out 249 00:06:56,720 --> 00:06:57,440 from the sun. 250 00:06:57,440 --> 00:06:57,940 OK. 251 00:06:57,940 --> 00:06:59,880 And then gradually migrated inward 252 00:06:59,880 --> 00:07:01,160 to its current position. 253 00:07:01,160 --> 00:07:01,840 Wow. 254 00:07:01,840 --> 00:07:03,380 Think of the impact that would have had 255 00:07:03,380 --> 00:07:04,800 on the rest of the solar system. 256 00:07:04,800 --> 00:07:07,160 What makes scientists think that happened? 257 00:07:07,160 --> 00:07:09,240 It's a bit like detective work, looking 258 00:07:09,240 --> 00:07:11,640 for clues from the structure of our solar system. 259 00:07:11,640 --> 00:07:12,160 OK. 260 00:07:12,160 --> 00:07:14,800 One piece of evidence lies in the asteroid belt 261 00:07:14,800 --> 00:07:16,520 between Mars and Jupiter. 262 00:07:16,520 --> 00:07:19,520 Some scientists believe that Jupiter's migration might 263 00:07:19,520 --> 00:07:22,840 have disrupted this region, scattering asteroids 264 00:07:22,840 --> 00:07:25,080 and preventing a planet from forming there. 265 00:07:25,080 --> 00:07:26,080 Interesting. 266 00:07:26,080 --> 00:07:29,000 It's a bit like Jupiter leaving a cosmic trail behind 267 00:07:29,000 --> 00:07:30,720 as it moved inward. 268 00:07:30,720 --> 00:07:33,560 So Jupiter's journey might have sculpted the asteroid belt 269 00:07:33,560 --> 00:07:34,480 as we know it today. 270 00:07:34,480 --> 00:07:35,040 Exactly. 271 00:07:35,040 --> 00:07:36,720 It's like a cosmic ripple effect. 272 00:07:36,720 --> 00:07:37,480 It really is. 273 00:07:37,480 --> 00:07:41,600 With one planet's movements impacting the entire system. 274 00:07:41,600 --> 00:07:42,840 But let's shift gears a bit. 275 00:07:42,840 --> 00:07:43,340 OK. 276 00:07:43,340 --> 00:07:45,880 We talk about gravity shaping planets and their orbits. 277 00:07:45,880 --> 00:07:46,600 Right. 278 00:07:46,600 --> 00:07:48,360 But there's another force at play 279 00:07:48,360 --> 00:07:49,600 that we haven't touched on yet. 280 00:07:49,600 --> 00:07:50,200 Oh, yeah. 281 00:07:50,200 --> 00:07:51,240 Magnetic fields. 282 00:07:51,240 --> 00:07:52,760 They're fascinating. 283 00:07:52,760 --> 00:07:54,920 What role do they play in this whole process? 284 00:07:54,920 --> 00:07:56,680 Magnetic fields are often overlooked. 285 00:07:56,680 --> 00:07:57,240 Yeah. 286 00:07:57,240 --> 00:08:00,560 But they play a significant role in the early stages 287 00:08:00,560 --> 00:08:01,880 of planet formation. 288 00:08:01,880 --> 00:08:02,400 OK. 289 00:08:02,400 --> 00:08:04,320 Remember those protoplanetary disks, 290 00:08:04,320 --> 00:08:05,720 the birthplaces of planets? 291 00:08:05,720 --> 00:08:06,220 Right. 292 00:08:06,220 --> 00:08:09,120 Well, they're not just swirling clouds of gas and dust. 293 00:08:09,120 --> 00:08:09,680 Right. 294 00:08:09,680 --> 00:08:12,280 They're also threaded with magnetic fields, 295 00:08:12,280 --> 00:08:15,380 which can influence how material moves and interacts 296 00:08:15,380 --> 00:08:16,640 within the disk. 297 00:08:16,640 --> 00:08:20,240 So magnetic fields add another layer of complexity 298 00:08:20,240 --> 00:08:22,200 to this already intricate process. 299 00:08:22,200 --> 00:08:22,880 They do. 300 00:08:22,880 --> 00:08:24,380 What kind of influence do they have? 301 00:08:24,380 --> 00:08:28,240 Think of magnetic fields as invisible threads. 302 00:08:28,240 --> 00:08:28,800 OK. 303 00:08:28,800 --> 00:08:31,040 Weaving through the disk and influencing 304 00:08:31,040 --> 00:08:32,200 the flow of material. 305 00:08:32,200 --> 00:08:32,700 OK. 306 00:08:32,700 --> 00:08:35,560 They can create turbulence and instabilities, 307 00:08:35,560 --> 00:08:37,920 which can affect the growth of planetesimals 308 00:08:37,920 --> 00:08:40,520 and the formation of protoplanetary cores. 309 00:08:40,520 --> 00:08:42,160 So they can really shake things up. 310 00:08:42,160 --> 00:08:45,760 They can, and they can even drive powerful jets 311 00:08:45,760 --> 00:08:47,840 of material outward from the star. 312 00:08:47,840 --> 00:08:48,400 Wow. 313 00:08:48,400 --> 00:08:50,200 Carving out cavities in the disk. 314 00:08:50,200 --> 00:08:52,880 It sounds like magnetic fields can be both creative 315 00:08:52,880 --> 00:08:54,320 and destructive forces. 316 00:08:54,320 --> 00:08:55,000 They are. 317 00:08:55,000 --> 00:08:56,880 Shaping the environment where planets are born. 318 00:08:56,880 --> 00:08:57,360 Yeah. 319 00:08:57,360 --> 00:08:59,120 It highlights the interconnectedness 320 00:08:59,120 --> 00:09:00,760 of everything in the universe. 321 00:09:00,760 --> 00:09:01,560 That's fascinating. 322 00:09:01,560 --> 00:09:04,760 Gravity, magnetism, radiation, they all work together. 323 00:09:04,760 --> 00:09:05,260 Wow. 324 00:09:05,260 --> 00:09:07,960 Like a cosmic orchestra to create the planets 325 00:09:07,960 --> 00:09:10,320 and solar systems we observe today. 326 00:09:10,320 --> 00:09:12,520 This deep dive has been full of surprises. 327 00:09:12,520 --> 00:09:13,280 It has. 328 00:09:13,280 --> 00:09:16,520 We've gone from tiny dust particles to migrating planets. 329 00:09:16,520 --> 00:09:17,960 It's an amazing journey. 330 00:09:17,960 --> 00:09:20,120 And the invisible hand of magnetic fields. 331 00:09:20,120 --> 00:09:20,620 It is. 332 00:09:20,620 --> 00:09:23,600 I'm starting to think that planet formation is less 333 00:09:23,600 --> 00:09:25,120 about simple accretion. 334 00:09:25,120 --> 00:09:25,680 Right. 335 00:09:25,680 --> 00:09:28,320 And more about a complex dance of forces, 336 00:09:28,320 --> 00:09:31,920 each playing a crucial role in shaping the final outcome. 337 00:09:31,920 --> 00:09:33,600 That's a great way to put it. 338 00:09:33,600 --> 00:09:35,720 And as we continue to study planet formation, 339 00:09:35,720 --> 00:09:39,160 we're realizing that it's an even more complex and dynamic 340 00:09:39,160 --> 00:09:41,480 process than we ever imagined. 341 00:09:41,480 --> 00:09:43,760 Welcome back to the final part of our deep dive 342 00:09:43,760 --> 00:09:44,920 into planet formation. 343 00:09:44,920 --> 00:09:46,600 The grand finale. 344 00:09:46,600 --> 00:09:48,480 You know, it's amazing to think about everything 345 00:09:48,480 --> 00:09:49,600 we've covered so far. 346 00:09:49,600 --> 00:09:50,120 Yeah. 347 00:09:50,120 --> 00:09:51,640 From those initial dust particles 348 00:09:51,640 --> 00:09:55,720 to migrating planets and the influence of magnetic fields. 349 00:09:55,720 --> 00:09:56,960 It's mind blowing. 350 00:09:56,960 --> 00:10:00,920 It really paints a picture of a dynamic and ever evolving 351 00:10:00,920 --> 00:10:01,480 universe. 352 00:10:01,480 --> 00:10:02,000 It does. 353 00:10:02,000 --> 00:10:03,960 And it makes you realize that our understanding 354 00:10:03,960 --> 00:10:06,400 of planet formation is constantly evolving. 355 00:10:06,400 --> 00:10:06,960 Absolutely. 356 00:10:06,960 --> 00:10:09,800 As we make new discoveries and refine our models. 357 00:10:09,800 --> 00:10:12,680 Speaking of the discoveries, one of the most exciting areas 358 00:10:12,680 --> 00:10:15,920 of research today is the search for planets 359 00:10:15,920 --> 00:10:18,000 beyond our solar system. 360 00:10:18,000 --> 00:10:18,880 Exoplanets? 361 00:10:18,880 --> 00:10:19,720 Exoplanets. 362 00:10:19,720 --> 00:10:21,880 Especially those that might be similar to Earth. 363 00:10:21,880 --> 00:10:22,320 Right. 364 00:10:22,320 --> 00:10:24,440 We've discovered thousands of exoplanets already. 365 00:10:24,440 --> 00:10:25,080 It's incredible. 366 00:10:25,080 --> 00:10:30,320 But the quest for another Earth, a planet that could potentially 367 00:10:30,320 --> 00:10:33,680 support life, it really captures the imagination. 368 00:10:33,680 --> 00:10:34,160 It does. 369 00:10:34,160 --> 00:10:37,000 And the pace of discovery has been incredible in recent years. 370 00:10:37,000 --> 00:10:37,520 It has. 371 00:10:37,520 --> 00:10:39,840 We're finding planets of all sizes and types. 372 00:10:39,840 --> 00:10:40,400 Oh, wow. 373 00:10:40,400 --> 00:10:42,280 Orbiting different kinds of stars. 374 00:10:42,280 --> 00:10:43,080 It's amazing. 375 00:10:43,080 --> 00:10:44,720 But what really gets people excited 376 00:10:44,720 --> 00:10:46,600 are those planets that fall within what 377 00:10:46,600 --> 00:10:48,120 we call the habitable zone. 378 00:10:48,120 --> 00:10:49,240 Right, the Goldilocks zone. 379 00:10:49,240 --> 00:10:49,720 Exactly. 380 00:10:49,720 --> 00:10:53,920 Not too hot, not too cold, just right for liquid water 381 00:10:53,920 --> 00:10:55,040 to exist on the surface. 382 00:10:55,040 --> 00:10:56,640 That's the sweet spot. 383 00:10:56,640 --> 00:10:58,880 That's considered a crucial ingredient for life 384 00:10:58,880 --> 00:10:59,720 as we know it. 385 00:10:59,720 --> 00:11:00,840 Absolutely. 386 00:11:00,840 --> 00:11:03,880 So are we finding many planets in these habitable zones? 387 00:11:03,880 --> 00:11:04,800 We are. 388 00:11:04,800 --> 00:11:07,400 And as our telescopes and observation techniques 389 00:11:07,400 --> 00:11:09,360 become more sophisticated, we're 390 00:11:09,360 --> 00:11:12,240 able to study these exoplanets in greater detail. 391 00:11:12,240 --> 00:11:12,880 That's exciting. 392 00:11:12,880 --> 00:11:14,680 We're not just detecting their presence. 393 00:11:14,680 --> 00:11:15,200 Right. 394 00:11:15,200 --> 00:11:17,640 We're starting to characterize their atmospheres. 395 00:11:17,640 --> 00:11:18,240 Oh, wow. 396 00:11:18,240 --> 00:11:21,280 And look for signs that might indicate the presence of life. 397 00:11:21,280 --> 00:11:23,800 So it's like we're playing cosmic detective, 398 00:11:23,800 --> 00:11:25,800 looking for clues on these distant worlds. 399 00:11:25,800 --> 00:11:27,520 What kind of signs are we looking for? 400 00:11:27,520 --> 00:11:30,080 We're searching for what we call biosignatures. 401 00:11:30,080 --> 00:11:30,920 Biosignatures. 402 00:11:30,920 --> 00:11:34,280 Yes, specific molecules or combinations of molecules 403 00:11:34,280 --> 00:11:36,120 in a planet's atmosphere that could indicate 404 00:11:36,120 --> 00:11:37,680 biological activity. 405 00:11:37,680 --> 00:11:38,520 Oh, I see. 406 00:11:38,520 --> 00:11:40,160 Oxygen is a key one. 407 00:11:40,160 --> 00:11:40,760 Oxygen. 408 00:11:40,760 --> 00:11:42,520 Especially when found in combination 409 00:11:42,520 --> 00:11:45,360 with gases like methane or ozone. 410 00:11:45,360 --> 00:11:47,840 These gases can be produced by living organisms 411 00:11:47,840 --> 00:11:49,600 and could be a telltale sign that we're 412 00:11:49,600 --> 00:11:51,560 not alone in the universe. 413 00:11:51,560 --> 00:11:53,600 It's mind boggling to think that we 414 00:11:53,600 --> 00:11:56,080 might be on the verge of detecting signs of life 415 00:11:56,080 --> 00:11:57,680 on other planets. 416 00:11:57,680 --> 00:12:00,200 It would truly revolutionize our understanding 417 00:12:00,200 --> 00:12:01,520 of our place in the cosmos. 418 00:12:01,520 --> 00:12:02,680 It would change everything. 419 00:12:02,680 --> 00:12:05,800 But the search for life isn't the only exciting frontier 420 00:12:05,800 --> 00:12:07,200 in planet formation, right? 421 00:12:07,200 --> 00:12:07,800 Right. 422 00:12:07,800 --> 00:12:10,080 What else are researchers focusing on? 423 00:12:10,080 --> 00:12:12,200 One area that's particularly fascinating 424 00:12:12,200 --> 00:12:14,720 is the study of planetary systems 425 00:12:14,720 --> 00:12:16,720 around different types of stars. 426 00:12:16,720 --> 00:12:17,200 Oh, OK. 427 00:12:17,200 --> 00:12:20,840 For a long time, we focused on stars like our sun. 428 00:12:20,840 --> 00:12:21,340 Right. 429 00:12:21,340 --> 00:12:22,920 But we're now realizing that stars 430 00:12:22,920 --> 00:12:24,920 come in a wide variety of sizes. 431 00:12:24,920 --> 00:12:27,920 Masses and temperatures and that diversity 432 00:12:27,920 --> 00:12:31,360 has a huge impact on the types of planets that can form. 433 00:12:31,360 --> 00:12:33,440 So it's not just a one size fits all recipe 434 00:12:33,440 --> 00:12:34,560 for planet formation. 435 00:12:34,560 --> 00:12:35,080 It's not. 436 00:12:35,080 --> 00:12:35,580 No. 437 00:12:35,580 --> 00:12:38,920 The type of star sets the stage for the kinds of planets 438 00:12:38,920 --> 00:12:39,760 that might emerge. 439 00:12:39,760 --> 00:12:40,520 Exactly. 440 00:12:40,520 --> 00:12:42,960 Take red dwarf stars, for example. 441 00:12:42,960 --> 00:12:44,200 Red dwarf stars. 442 00:12:44,200 --> 00:12:46,640 Much smaller and cooler than our sun. 443 00:12:46,640 --> 00:12:50,040 And they're incredibly common in the Milky Way galaxy. 444 00:12:50,040 --> 00:12:52,920 Their habitable zones are much closer in, 445 00:12:52,920 --> 00:12:55,280 which means that planets in those zones 446 00:12:55,280 --> 00:12:57,880 would experience stronger gravitational forces 447 00:12:57,880 --> 00:12:59,040 from the star. 448 00:12:59,040 --> 00:13:03,200 So planets around red dwarfs would be baked on one side 449 00:13:03,200 --> 00:13:04,280 and frozen on the other. 450 00:13:04,280 --> 00:13:05,280 Pretty much, yeah. 451 00:13:05,280 --> 00:13:07,600 That sounds like a pretty extreme environment for life 452 00:13:07,600 --> 00:13:08,240 as we know it. 453 00:13:08,240 --> 00:13:11,120 It does, but it also raises some really interesting questions 454 00:13:11,120 --> 00:13:12,760 about the adaptability of life. 455 00:13:12,760 --> 00:13:13,440 Right. 456 00:13:13,440 --> 00:13:16,840 Could life find a way to thrive in such extreme conditions? 457 00:13:16,840 --> 00:13:17,720 It makes you wonder. 458 00:13:17,720 --> 00:13:18,680 We just don't know yet. 459 00:13:18,680 --> 00:13:19,180 Right. 460 00:13:19,180 --> 00:13:21,100 And that's what makes it so exciting to study. 461 00:13:21,100 --> 00:13:23,440 This deep dive has been a real eye opener. 462 00:13:23,440 --> 00:13:26,760 It's clear that planet formation is a much more complex and 463 00:13:26,760 --> 00:13:29,440 nuanced process than I ever imagined. 464 00:13:29,440 --> 00:13:31,000 And any of us imagined. 465 00:13:31,000 --> 00:13:33,440 We've gone from thinking about simple collisions 466 00:13:33,440 --> 00:13:37,240 to exploring the influence of gravity, magnetic fields, 467 00:13:37,240 --> 00:13:40,080 planetary migration, and the characteristics 468 00:13:40,080 --> 00:13:41,400 of different types of stars. 469 00:13:41,400 --> 00:13:42,560 It's quite a journey. 470 00:13:42,560 --> 00:13:45,240 It's incredible to see how all these factors come together 471 00:13:45,240 --> 00:13:47,560 to create the incredible diversity of planets 472 00:13:47,560 --> 00:13:48,800 we observe in the universe. 473 00:13:48,800 --> 00:13:51,640 And the journey of discovery is far from over. 474 00:13:51,640 --> 00:13:54,480 There are still so many unanswered questions 475 00:13:54,480 --> 00:13:55,960 and mysteries to unravel. 476 00:13:55,960 --> 00:13:56,960 Like what? 477 00:13:56,960 --> 00:14:01,280 How exactly do protoplanetary disks evolve and give rise 478 00:14:01,280 --> 00:14:02,680 to planetary systems? 479 00:14:02,680 --> 00:14:03,600 That's a good question. 480 00:14:03,600 --> 00:14:06,440 What role do giant impacts play in shaping 481 00:14:06,440 --> 00:14:08,280 planets and their moons? 482 00:14:08,280 --> 00:14:10,600 And perhaps the biggest question of all, 483 00:14:10,600 --> 00:14:12,320 are we alone in the universe? 484 00:14:12,320 --> 00:14:14,920 It's both humbling and inspiring to realize 485 00:14:14,920 --> 00:14:16,640 how much we still don't know. 486 00:14:16,640 --> 00:14:17,320 It is. 487 00:14:17,320 --> 00:14:19,600 But it's also a testament to human curiosity 488 00:14:19,600 --> 00:14:21,920 and our drive to explore the unknown. 489 00:14:21,920 --> 00:14:22,440 Absolutely. 490 00:14:22,440 --> 00:14:24,480 Thank you for taking us on this incredible journey 491 00:14:24,480 --> 00:14:26,840 through the fascinating world of planet formation. 492 00:14:26,840 --> 00:14:28,120 It's been my pleasure. 493 00:14:28,120 --> 00:14:30,440 And to our listeners, thank you for joining us 494 00:14:30,440 --> 00:14:32,560 on this episode of Cosmos in a Pod. 495 00:14:32,560 --> 00:14:34,240 Until next time. 496 00:14:34,240 --> 00:14:37,440 We hope you enjoyed our deep dive into planet formation. 497 00:14:37,440 --> 00:14:39,760 Don't forget to follow and subscribe to the podcast 498 00:14:39,760 --> 00:14:55,400 for more explorations of the cosmos.