1 00:00:00,000 --> 00:00:03,960 Welcome back to Cosmos in a Pod Space and Astronomy series. 2 00:00:03,960 --> 00:00:05,840 You probably look up at the moon all the time. 3 00:00:05,840 --> 00:00:06,680 Yeah. 4 00:00:06,680 --> 00:00:08,960 But have you ever stopped to think about how it got there? 5 00:00:08,960 --> 00:00:10,480 Hmm, I know I have. 6 00:00:10,480 --> 00:00:13,840 It's a truly epic origin story. 7 00:00:13,840 --> 00:00:14,680 It is. 8 00:00:14,680 --> 00:00:15,520 Cosmic chaos. 9 00:00:15,520 --> 00:00:16,360 Oh yeah. 10 00:00:16,360 --> 00:00:17,320 Violent collisions. 11 00:00:17,320 --> 00:00:18,160 Absolutely. 12 00:00:18,160 --> 00:00:20,000 And a journey from a molten world 13 00:00:20,000 --> 00:00:22,160 to the thriving planet we call home. 14 00:00:22,160 --> 00:00:23,000 That's right. 15 00:00:23,000 --> 00:00:24,600 Buckle up, it's gonna be a wild ride. 16 00:00:24,600 --> 00:00:26,600 It's a story that takes us all the way back 17 00:00:26,600 --> 00:00:28,200 to the very beginning of our solar system. 18 00:00:28,200 --> 00:00:29,040 Okay. 19 00:00:29,040 --> 00:00:31,360 4.6 billion years ago. 20 00:00:31,360 --> 00:00:32,200 Wow. 21 00:00:32,200 --> 00:00:33,040 Back then. 22 00:00:33,040 --> 00:00:33,880 Yeah. 23 00:00:33,880 --> 00:00:38,400 Imagine a swirling disk of gas and dust. 24 00:00:38,400 --> 00:00:39,240 I'm trying to picture it? 25 00:00:39,240 --> 00:00:41,120 The remnants of the sun's birth. 26 00:00:41,120 --> 00:00:41,960 Okay. 27 00:00:41,960 --> 00:00:44,040 It's in this chaotic cloud that the seeds of earth 28 00:00:44,040 --> 00:00:45,440 and the moon were sown. 29 00:00:46,360 --> 00:00:50,080 So how do we go from this swirling cloud of dust 30 00:00:50,080 --> 00:00:52,040 to a solid planet? 31 00:00:53,160 --> 00:00:54,320 Doesn't sound like those two things 32 00:00:54,320 --> 00:00:55,200 go together very well. 33 00:00:55,200 --> 00:00:56,960 It's a process called accretion. 34 00:00:56,960 --> 00:00:57,800 Okay. 35 00:00:57,800 --> 00:00:59,200 It's more exciting than it sounds. 36 00:00:59,200 --> 00:01:02,000 Think of it like a cosmic snowball effect. 37 00:01:02,000 --> 00:01:05,960 Tiny particles of dust drawn together by static electricity 38 00:01:05,960 --> 00:01:07,360 start to clump together. 39 00:01:07,360 --> 00:01:10,360 As these clumps grow, their gravity increases. 40 00:01:10,360 --> 00:01:11,200 Makes sense. 41 00:01:11,200 --> 00:01:12,440 Pulling in more and more material. 42 00:01:12,440 --> 00:01:13,480 So it's a runaway train. 43 00:01:13,480 --> 00:01:14,320 Exactly. 44 00:01:14,320 --> 00:01:15,840 Building and building until you have a planet. 45 00:01:15,840 --> 00:01:19,000 And these baby planets or protoplanets 46 00:01:19,000 --> 00:01:22,720 were forming all over the early solar system. 47 00:01:22,720 --> 00:01:23,560 Got it. 48 00:01:23,560 --> 00:01:25,280 One of these, of course, was our own earth 49 00:01:25,280 --> 00:01:26,720 forming in the inner solar system 50 00:01:26,720 --> 00:01:29,480 where it was hot enough for rocky 51 00:01:29,480 --> 00:01:32,200 and metallic materials to solidify. 52 00:01:32,200 --> 00:01:36,720 So earth was basically a giant molten ball 53 00:01:36,720 --> 00:01:38,480 of rock and metal at this point. 54 00:01:38,480 --> 00:01:39,840 It was. 55 00:01:39,840 --> 00:01:43,360 But how did it get its layered structure? 56 00:01:43,360 --> 00:01:44,200 Okay. 57 00:01:44,200 --> 00:01:46,640 The core, mantle, and crust. 58 00:01:46,640 --> 00:01:48,680 We know that's important for a lot of reasons. 59 00:01:48,680 --> 00:01:49,520 Definitely. 60 00:01:49,520 --> 00:01:51,920 But I can never remember exactly how it happened. 61 00:01:51,920 --> 00:01:53,040 That's a great question. 62 00:01:53,040 --> 00:01:56,320 It's all thanks to a process called differentiation. 63 00:01:56,320 --> 00:01:59,400 As earth grew and continued to be bombarded 64 00:01:59,400 --> 00:02:02,680 by space debris, it heated up even more. 65 00:02:02,680 --> 00:02:05,720 Eventually becoming completely molten. 66 00:02:05,720 --> 00:02:07,440 So like a giant lava lamp. 67 00:02:07,440 --> 00:02:10,640 In this molten state, heavier elements, 68 00:02:10,640 --> 00:02:13,880 like iron and nickel, sank to the center, 69 00:02:13,880 --> 00:02:15,520 forming the core. 70 00:02:15,520 --> 00:02:19,520 Meanwhile, lighter elements, like silicates, 71 00:02:19,520 --> 00:02:24,320 rose to the surface, forming the mantle and crust. 72 00:02:24,320 --> 00:02:25,160 Oh, right. 73 00:02:25,160 --> 00:02:30,160 Imagine it like a giant cosmic sorting machine. 74 00:02:30,160 --> 00:02:31,880 So the heaviest stuff sinks to the bottom 75 00:02:31,880 --> 00:02:33,680 and the lightest stuff floats to the top. 76 00:02:33,680 --> 00:02:34,520 Right. 77 00:02:34,520 --> 00:02:35,360 Just like oil and water. 78 00:02:35,360 --> 00:02:36,280 That's a good analogy. 79 00:02:36,280 --> 00:02:37,560 But on a planetary scale. 80 00:02:37,560 --> 00:02:40,760 And this layering is crucial for everything 81 00:02:40,760 --> 00:02:44,800 from plate tectonics to the earth's magnetic field. 82 00:02:44,800 --> 00:02:45,640 Wow. 83 00:02:45,640 --> 00:02:47,280 It's the foundation of the dynamic planet 84 00:02:47,280 --> 00:02:48,280 we live on today. 85 00:02:48,280 --> 00:02:49,640 Okay, so we have earth. 86 00:02:49,640 --> 00:02:50,480 Yeah. 87 00:02:50,480 --> 00:02:52,040 A molten, chaotic world. 88 00:02:52,040 --> 00:02:52,880 Yeah. 89 00:02:52,880 --> 00:02:54,440 Constantly being bombarded by meteors. 90 00:02:54,440 --> 00:02:57,680 Definitely not the place to go for a weekend getaway. 91 00:02:57,680 --> 00:02:58,520 Probably not. 92 00:02:58,520 --> 00:02:59,880 But what about the moon? 93 00:02:59,880 --> 00:03:02,960 Where does it fit into this story of fire and brimstone? 94 00:03:02,960 --> 00:03:05,840 Ah, the moon. 95 00:03:05,840 --> 00:03:08,720 Its formation is one of the most dramatic chapters 96 00:03:08,720 --> 00:03:10,680 in earth's early history. 97 00:03:10,680 --> 00:03:13,000 The leading theory, and it's a good one, 98 00:03:13,000 --> 00:03:14,880 is the giant impact hypothesis. 99 00:03:14,880 --> 00:03:15,720 Okay. 100 00:03:15,720 --> 00:03:17,680 Which suggests that the moon was born 101 00:03:17,680 --> 00:03:19,320 from a colossal collision. 102 00:03:19,320 --> 00:03:21,200 Okay, you've gotta give me more details on that one. 103 00:03:21,200 --> 00:03:22,040 All right. 104 00:03:22,040 --> 00:03:24,400 Because a colossal collision sounds pretty intense. 105 00:03:24,400 --> 00:03:25,720 Picture this. 106 00:03:25,720 --> 00:03:28,560 A Mars-sized protoplanet, 107 00:03:28,560 --> 00:03:30,920 which scientists have named Theia, 108 00:03:30,920 --> 00:03:34,080 slams into earth at an incredible speed. 109 00:03:34,080 --> 00:03:37,520 We're talking about an impact so powerful 110 00:03:37,520 --> 00:03:41,320 that it vaporizes a good chunk of earth's mantle 111 00:03:41,320 --> 00:03:44,560 and a significant portion of Theia itself. 112 00:03:44,560 --> 00:03:46,040 That's absolutely mind-blowing. 113 00:03:46,040 --> 00:03:47,000 Yeah, it is. 114 00:03:47,000 --> 00:03:49,520 So what happened to all that vaporized rock and debris 115 00:03:49,520 --> 00:03:51,320 from this epic cosmic crash? 116 00:03:51,320 --> 00:03:52,240 I can't even imagine. 117 00:03:52,240 --> 00:03:55,200 It formed a massive superheated disk of debris 118 00:03:55,200 --> 00:03:57,960 orbiting the earth over millions of years. 119 00:03:57,960 --> 00:03:58,800 Wow. 120 00:03:58,800 --> 00:04:00,680 This debris, drawn together by gravity, 121 00:04:00,680 --> 00:04:04,920 cooled and coalesced to form, you guessed it, the moon. 122 00:04:04,920 --> 00:04:07,720 So the moon is like a giant space scar 123 00:04:07,720 --> 00:04:10,920 from this ancient planetary fender bender. 124 00:04:10,920 --> 00:04:11,760 You could say that. 125 00:04:11,760 --> 00:04:12,760 That's incredible. 126 00:04:12,760 --> 00:04:15,840 But is there any actual evidence to support this theory? 127 00:04:15,840 --> 00:04:17,000 I mean, it sounds like something out 128 00:04:17,000 --> 00:04:18,240 of a science fiction movie. 129 00:04:18,240 --> 00:04:20,800 There's actually quite a bit of evidence. 130 00:04:20,800 --> 00:04:25,120 First, lunar rocks brought back from the Apollo missions 131 00:04:25,120 --> 00:04:27,240 have a chemical composition that's 132 00:04:27,240 --> 00:04:29,800 strikingly similar to Earth's mantle, 133 00:04:29,800 --> 00:04:31,600 suggesting they have a shared origin. 134 00:04:31,600 --> 00:04:33,200 So they're like cosmic siblings. 135 00:04:33,200 --> 00:04:33,720 Exactly. 136 00:04:33,720 --> 00:04:37,080 Made from the same stardust, but living different lives. 137 00:04:37,080 --> 00:04:42,880 Second, the moon is surprisingly lacking in volatile elements. 138 00:04:42,880 --> 00:04:43,800 Volatile elements. 139 00:04:43,800 --> 00:04:47,640 Things that evaporate easily at relatively low temperatures. 140 00:04:47,640 --> 00:04:48,200 Got it. 141 00:04:48,200 --> 00:04:51,040 This makes perfect sense if it formed from material that 142 00:04:51,040 --> 00:04:53,200 was superheated during a massive impact. 143 00:04:53,200 --> 00:04:53,960 Makes sense. 144 00:04:53,960 --> 00:04:56,600 All those volatile elements would have been blasted off 145 00:04:56,600 --> 00:04:57,320 into space. 146 00:04:57,320 --> 00:04:59,080 Like the impact flash baked the moon. 147 00:04:59,080 --> 00:04:59,680 Right. 148 00:04:59,680 --> 00:05:02,560 Leaving behind a very specific set of ingredients. 149 00:05:02,560 --> 00:05:03,240 Exactly. 150 00:05:03,240 --> 00:05:04,600 I never thought about it that way. 151 00:05:04,600 --> 00:05:08,240 Is there any other evidence that supports the giant impact 152 00:05:08,240 --> 00:05:09,840 theory? 153 00:05:09,840 --> 00:05:10,400 Is there? 154 00:05:10,400 --> 00:05:13,680 Think about our seasons, which are caused by the Earth's tilt 155 00:05:13,680 --> 00:05:15,120 on its axis. 156 00:05:15,120 --> 00:05:18,440 That tilt, that 23.5 degree angle, 157 00:05:18,440 --> 00:05:22,360 is likely a direct result of the giant impact. 158 00:05:22,360 --> 00:05:25,200 The collision would have knocked Earth off kilter, 159 00:05:25,200 --> 00:05:27,200 giving it the tilt we know today. 160 00:05:27,200 --> 00:05:30,800 So the moon's birth not only shaped our planet physically, 161 00:05:30,800 --> 00:05:32,800 but also gave us the seasons. 162 00:05:32,800 --> 00:05:34,320 And as a result, our climate. 163 00:05:34,320 --> 00:05:36,640 It's a pretty amazing chain of events. 164 00:05:36,640 --> 00:05:37,480 Yeah, it is. 165 00:05:37,480 --> 00:05:40,440 And we're only just starting to understand all the ways 166 00:05:40,440 --> 00:05:42,400 the moon has shaped the Earth. 167 00:05:42,400 --> 00:05:46,600 What's fascinating to me is that the early Earth-moon system 168 00:05:46,600 --> 00:05:48,800 would have looked vastly different from what 169 00:05:48,800 --> 00:05:49,600 we see today. 170 00:05:49,600 --> 00:05:51,320 OK, I'm definitely intrigued by this. 171 00:05:51,320 --> 00:05:52,160 All right. 172 00:05:52,160 --> 00:05:56,480 Paint me a picture of this early Earth-moon relationship. 173 00:05:56,480 --> 00:05:59,320 Imagine a much larger moon. 174 00:05:59,320 --> 00:06:00,760 OK, a larger moon. 175 00:06:00,760 --> 00:06:04,640 A massive glowing orb dominating the night sky. 176 00:06:04,640 --> 00:06:05,160 Wow. 177 00:06:05,160 --> 00:06:07,200 Remember, it was much closer to Earth back then. 178 00:06:07,200 --> 00:06:07,680 Right. 179 00:06:07,680 --> 00:06:10,920 And because of that proximity, the gravitational pull 180 00:06:10,920 --> 00:06:14,640 between them was much stronger, generating much stronger tidal 181 00:06:14,640 --> 00:06:16,160 forces on Earth. 182 00:06:16,160 --> 00:06:17,720 You're talking about mega tsunamis. 183 00:06:17,720 --> 00:06:18,360 We've got it. 184 00:06:18,360 --> 00:06:20,480 Way bigger than anything we see today, right? 185 00:06:20,480 --> 00:06:21,160 Yeah. 186 00:06:21,160 --> 00:06:25,080 I can imagine all that extra gravity causing some seriously 187 00:06:25,080 --> 00:06:26,840 extreme tides. 188 00:06:26,840 --> 00:06:29,240 Those incredible tidal forces also 189 00:06:29,240 --> 00:06:33,480 influenced Earth's rotation, slowly but surely putting 190 00:06:33,480 --> 00:06:35,800 the brakes on how fast it spins. 191 00:06:35,800 --> 00:06:37,520 In fact, those tidal interactions still 192 00:06:37,520 --> 00:06:38,400 happen today. 193 00:06:38,400 --> 00:06:38,920 They do. 194 00:06:38,920 --> 00:06:41,760 And are pushing the moon further away from Earth. 195 00:06:41,760 --> 00:06:42,280 Really? 196 00:06:42,280 --> 00:06:44,280 Albeit very, very slowly. 197 00:06:44,280 --> 00:06:47,120 So the moon is slowly drifting away from us. 198 00:06:47,120 --> 00:06:47,640 It is. 199 00:06:47,640 --> 00:06:48,960 A little bit every year. 200 00:06:48,960 --> 00:06:49,720 That's right. 201 00:06:49,720 --> 00:06:51,240 What a bittersweet thought. 202 00:06:51,240 --> 00:06:53,240 But I guess all good things must change. 203 00:06:53,240 --> 00:06:53,760 That's true. 204 00:06:53,760 --> 00:06:55,120 Even on a cosmic scale. 205 00:06:55,120 --> 00:06:57,240 This raises an important question for me. 206 00:06:57,240 --> 00:06:57,640 Yeah. 207 00:06:57,640 --> 00:07:00,520 What role did the moon play in making 208 00:07:00,520 --> 00:07:02,320 Earth habitable in the first place? 209 00:07:02,320 --> 00:07:03,440 Yeah, that's a good question. 210 00:07:03,440 --> 00:07:06,360 It sounds like it did a lot more than just cause tides. 211 00:07:06,360 --> 00:07:07,720 That's an excellent question. 212 00:07:07,720 --> 00:07:08,400 Oh. 213 00:07:08,400 --> 00:07:11,720 We know that the moon played a crucial role in stabilizing 214 00:07:11,720 --> 00:07:13,080 Earth's axial tilt. 215 00:07:13,080 --> 00:07:13,720 Right. 216 00:07:13,720 --> 00:07:15,800 And that stability is really important. 217 00:07:15,800 --> 00:07:16,280 It is. 218 00:07:16,280 --> 00:07:19,840 Without the moon's influence, Earth's tilt 219 00:07:19,840 --> 00:07:23,800 would fluctuate wildly, causing extreme and unpredictable 220 00:07:23,800 --> 00:07:24,720 climate swings. 221 00:07:24,720 --> 00:07:25,520 Exactly. 222 00:07:25,520 --> 00:07:29,240 So we're talking ice ages popping up randomly, 223 00:07:29,240 --> 00:07:32,360 tropical heat waves in the Arctic, basically, climate 224 00:07:32,360 --> 00:07:33,320 chaos. 225 00:07:33,320 --> 00:07:35,560 I could see how that would make it pretty hard for life 226 00:07:35,560 --> 00:07:36,960 to get a foothold. 227 00:07:36,960 --> 00:07:40,680 Very likely that complex life, as we know it, 228 00:07:40,680 --> 00:07:43,120 could never have evolved under those conditions. 229 00:07:43,120 --> 00:07:44,000 That makes sense. 230 00:07:44,000 --> 00:07:47,080 So the moon wasn't just a pretty face in the night sky. 231 00:07:47,080 --> 00:07:50,920 It acted as our planet's silent guardian, 232 00:07:50,920 --> 00:07:54,240 keeping our climate stable and allowing life to thrive. 233 00:07:54,240 --> 00:07:56,360 It really makes you appreciate all the things 234 00:07:56,360 --> 00:07:57,480 the moon does for us. 235 00:07:57,480 --> 00:07:58,560 Yeah, it does. 236 00:07:58,560 --> 00:08:02,160 And to think all that came from a giant cosmic collision 237 00:08:02,160 --> 00:08:03,400 billions of years ago. 238 00:08:03,400 --> 00:08:04,440 It's pretty remarkable. 239 00:08:04,440 --> 00:08:06,680 But even after the moon's formation, 240 00:08:06,680 --> 00:08:09,600 Earth was still a pretty wild and hostile place, right? 241 00:08:09,600 --> 00:08:10,320 Oh, it was. 242 00:08:10,320 --> 00:08:11,640 It wasn't exactly a paradise yet. 243 00:08:11,640 --> 00:08:12,160 You're right. 244 00:08:12,160 --> 00:08:14,080 It was still a world in transition. 245 00:08:14,080 --> 00:08:14,800 OK. 246 00:08:14,800 --> 00:08:17,880 But things were definitely starting to calm down a bit. 247 00:08:17,880 --> 00:08:19,080 So things were getting better. 248 00:08:19,080 --> 00:08:22,840 The constant bombardment from meteors began to ease, 249 00:08:22,840 --> 00:08:25,240 and Earth began to cool, allowing 250 00:08:25,240 --> 00:08:27,400 its crust to solidify. 251 00:08:27,400 --> 00:08:29,920 Volcanic activity became more prevalent, 252 00:08:29,920 --> 00:08:33,560 releasing gases from Earth's interior, which 253 00:08:33,560 --> 00:08:35,480 helped form the first atmosphere. 254 00:08:35,480 --> 00:08:39,080 So Earth was basically exhaling its first breath. 255 00:08:39,080 --> 00:08:41,920 And that was the beginning of the atmosphere we breathe today. 256 00:08:41,920 --> 00:08:42,680 You could say that. 257 00:08:42,680 --> 00:08:43,520 That's amazing. 258 00:08:43,520 --> 00:08:45,560 Of course, that early atmosphere was nothing 259 00:08:45,560 --> 00:08:46,880 like the air we breathe today. 260 00:08:46,880 --> 00:08:47,760 I can imagine. 261 00:08:47,760 --> 00:08:52,720 It was a hazy mix of carbon dioxide, methane, water vapor. 262 00:08:52,720 --> 00:08:53,280 Right. 263 00:08:53,280 --> 00:08:55,760 Not exactly a healthy mix for us humans. 264 00:08:55,760 --> 00:08:56,560 Definitely not. 265 00:08:56,560 --> 00:08:59,680 But this was a crucial step in Earth's journey 266 00:08:59,680 --> 00:09:01,000 toward habitability. 267 00:09:01,000 --> 00:09:02,560 This is such an incredible story. 268 00:09:02,560 --> 00:09:03,240 It is. 269 00:09:03,240 --> 00:09:06,360 But I'm sure there's a lot more to uncover about this early 270 00:09:06,360 --> 00:09:07,720 Earth and all the changes that happened. 271 00:09:07,720 --> 00:09:08,320 There is. 272 00:09:08,320 --> 00:09:10,640 It feels like we've only just scratched the surface. 273 00:09:10,640 --> 00:09:11,640 You're right about that. 274 00:09:11,640 --> 00:09:13,240 There's so much more to explore. 275 00:09:13,240 --> 00:09:13,720 Yeah. 276 00:09:13,720 --> 00:09:15,880 Maybe this is a good place to pause and pick up 277 00:09:15,880 --> 00:09:18,280 the rest of this epic tale in part two. 278 00:09:18,280 --> 00:09:19,440 I'm already hooked. 279 00:09:19,440 --> 00:09:21,240 Let's definitely continue this deep dive. 280 00:09:21,240 --> 00:09:22,800 Sounds good to me. 281 00:09:22,800 --> 00:09:24,360 We'll pick up right where we left off. 282 00:09:24,360 --> 00:09:26,200 Welcome back to Cosmos in a Pod. 283 00:09:26,200 --> 00:09:29,800 Last time we left off with Earth finally 284 00:09:29,800 --> 00:09:31,760 starting to chill out a bit after the drama 285 00:09:31,760 --> 00:09:32,840 of the moon's formation. 286 00:09:32,840 --> 00:09:33,340 Right. 287 00:09:33,340 --> 00:09:35,960 The cosmic dust had settled literally. 288 00:09:35,960 --> 00:09:39,360 We had a layered Earth, a brand new moon, 289 00:09:39,360 --> 00:09:42,200 and those first oceans were starting to form. 290 00:09:42,200 --> 00:09:44,000 It's really incredible. 291 00:09:44,000 --> 00:09:45,500 I'm ready to hear what happened next. 292 00:09:45,500 --> 00:09:47,320 This is where things get really exciting, 293 00:09:47,320 --> 00:09:50,200 because this is when Earth starts on its path 294 00:09:50,200 --> 00:09:52,520 to becoming the habitable planet we know and love. 295 00:09:52,520 --> 00:09:54,280 OK, set the scene for me. 296 00:09:54,280 --> 00:09:57,240 What did Earth actually look like at this point? 297 00:09:57,240 --> 00:09:59,480 Imagine a world that's still pretty hot. 298 00:09:59,480 --> 00:10:00,040 Hot. 299 00:10:00,040 --> 00:10:03,400 Volcanoes are erupting everywhere, 300 00:10:03,400 --> 00:10:07,000 spewing out lava and gases into the atmosphere. 301 00:10:07,000 --> 00:10:07,920 OK. 302 00:10:07,920 --> 00:10:10,600 The sky wouldn't have been that clear blue we're used to. 303 00:10:10,600 --> 00:10:11,120 I see. 304 00:10:11,120 --> 00:10:14,880 It would have been a hazy mix of carbon dioxide, methane, 305 00:10:14,880 --> 00:10:16,000 and water vapor. 306 00:10:16,000 --> 00:10:17,760 Not exactly breathable. 307 00:10:17,760 --> 00:10:18,640 No, not at all. 308 00:10:18,640 --> 00:10:21,880 How did we go from that toxic soup to the air we have now? 309 00:10:21,880 --> 00:10:25,800 Well, one of the key players was those newly formed oceans. 310 00:10:25,800 --> 00:10:26,960 Oh, the oceans? 311 00:10:26,960 --> 00:10:29,600 Remember, Earth was still cooling down as it did. 312 00:10:29,600 --> 00:10:30,100 Yeah. 313 00:10:30,100 --> 00:10:33,760 All that water vapor in the atmosphere started to condense 314 00:10:33,760 --> 00:10:35,720 and fell as torrential rain. 315 00:10:35,720 --> 00:10:37,400 Like mega rain. 316 00:10:37,400 --> 00:10:39,400 Talk about a bad hair day. 317 00:10:39,400 --> 00:10:40,320 I'd say so. 318 00:10:40,320 --> 00:10:42,920 This rain filled the huge basins that eventually 319 00:10:42,920 --> 00:10:44,440 became our oceans. 320 00:10:44,440 --> 00:10:47,440 So the oceans were like giant air purifiers, 321 00:10:47,440 --> 00:10:50,320 sucking up some of those harmful gases from the atmosphere. 322 00:10:50,320 --> 00:10:51,960 That's a great way to think about it. 323 00:10:51,960 --> 00:10:54,920 The oceans played a huge role in regulating 324 00:10:54,920 --> 00:10:57,480 what the early atmosphere was made of. 325 00:10:57,480 --> 00:11:00,240 They absorbed a lot of that carbon dioxide, 326 00:11:00,240 --> 00:11:03,720 which eventually got locked away in rocks and sediments. 327 00:11:03,720 --> 00:11:06,240 So they were cleaning up the atmosphere. 328 00:11:06,240 --> 00:11:07,360 Yeah, in a way. 329 00:11:07,360 --> 00:11:10,000 OK, so the oceans were like a giant carbon sink. 330 00:11:10,000 --> 00:11:10,520 Exactly. 331 00:11:10,520 --> 00:11:13,680 Pulling CO2 out of the air and cooling down the planet even 332 00:11:13,680 --> 00:11:14,160 more. 333 00:11:14,160 --> 00:11:16,440 And all that cooling was essential for life 334 00:11:16,440 --> 00:11:17,160 as we know it. 335 00:11:17,160 --> 00:11:17,840 Oh, ice? 336 00:11:17,840 --> 00:11:20,760 As the temperatures dropped, more and more of the water 337 00:11:20,760 --> 00:11:23,180 vapor in the atmosphere condensed, 338 00:11:23,180 --> 00:11:25,400 which eventually led to clearer skies 339 00:11:25,400 --> 00:11:28,120 and a more temperate, stable climate. 340 00:11:28,120 --> 00:11:30,160 So it was starting to look like a place 341 00:11:30,160 --> 00:11:31,120 we could actually live. 342 00:11:31,120 --> 00:11:32,080 Yeah, it was. 343 00:11:32,080 --> 00:11:35,440 We're getting closer and closer to the Earth we recognize. 344 00:11:35,440 --> 00:11:38,840 But there's still one big piece missing. 345 00:11:38,840 --> 00:11:39,400 Oxygen. 346 00:11:39,400 --> 00:11:39,920 Right. 347 00:11:39,920 --> 00:11:41,320 Where did that come from? 348 00:11:41,320 --> 00:11:42,640 Oxygen. 349 00:11:42,640 --> 00:11:43,280 The big one. 350 00:11:43,280 --> 00:11:44,280 The breath of life. 351 00:11:44,280 --> 00:11:45,520 That's a whole other story. 352 00:11:45,520 --> 00:11:47,080 I found a fascinating one. 353 00:11:47,080 --> 00:11:47,720 Is it really? 354 00:11:47,720 --> 00:11:51,560 See, the early atmosphere hardly had any free oxygen. 355 00:11:51,560 --> 00:11:56,440 It wasn't until photosynthetic organisms evolved billions 356 00:11:56,440 --> 00:11:57,560 of years later. 357 00:11:57,560 --> 00:11:58,320 So way later. 358 00:11:58,320 --> 00:12:00,960 That oxygen levels really started to rise. 359 00:12:00,960 --> 00:12:04,000 So those tiny bacteria are responsible for all 360 00:12:04,000 --> 00:12:05,080 the oxygen we breathe. 361 00:12:05,080 --> 00:12:05,760 Yeah. 362 00:12:05,760 --> 00:12:08,200 You're talking about those microscopic bacteria, right? 363 00:12:08,200 --> 00:12:09,800 They were just doing their thing, 364 00:12:09,800 --> 00:12:11,480 pumping out oxygen as a byproduct. 365 00:12:11,480 --> 00:12:12,680 But it was a side effect. 366 00:12:12,680 --> 00:12:14,760 And completely transformed the Earth's 367 00:12:14,760 --> 00:12:16,360 atmosphere in the process. 368 00:12:16,360 --> 00:12:18,560 It's incredible how these tiny creatures made 369 00:12:18,560 --> 00:12:19,600 such a huge impact. 370 00:12:19,600 --> 00:12:20,560 It's mind blowing. 371 00:12:20,560 --> 00:12:21,280 It is. 372 00:12:21,280 --> 00:12:24,880 The very air we breathe is a result of billions 373 00:12:24,880 --> 00:12:26,560 of years of their hard work. 374 00:12:26,560 --> 00:12:27,280 Yeah. 375 00:12:27,280 --> 00:12:28,200 Isn't that amazing? 376 00:12:28,200 --> 00:12:30,040 It really makes you appreciate those little guys, 377 00:12:30,040 --> 00:12:30,600 doesn't it? 378 00:12:30,600 --> 00:12:31,280 For sure. 379 00:12:31,280 --> 00:12:33,560 Let's shift gears back to the moon for a second. 380 00:12:33,560 --> 00:12:34,080 All right. 381 00:12:34,080 --> 00:12:37,360 We talked about how it stabilized Earth's tilt. 382 00:12:37,360 --> 00:12:40,520 But are there any other big ways the moon affected our planet? 383 00:12:40,520 --> 00:12:41,680 Oh, absolutely. 384 00:12:41,680 --> 00:12:42,080 OK. 385 00:12:42,080 --> 00:12:43,000 What else did it do? 386 00:12:43,000 --> 00:12:45,520 The moon's influence on Earth is way more profound 387 00:12:45,520 --> 00:12:47,120 than most people realize. 388 00:12:47,120 --> 00:12:47,880 Like what? 389 00:12:47,880 --> 00:12:51,000 Its gravity is the main driver of our ocean tides. 390 00:12:51,000 --> 00:12:52,160 Oh, the tides. 391 00:12:52,160 --> 00:12:54,360 Which create that rhythmic ebb and flow 392 00:12:54,360 --> 00:12:56,560 we see along our coastlines. 393 00:12:56,560 --> 00:12:58,680 Tides are definitely beautiful to look at. 394 00:12:58,680 --> 00:12:59,360 They are. 395 00:12:59,360 --> 00:13:01,040 But they also do so much more than that. 396 00:13:01,040 --> 00:13:02,440 Yeah, that's right. 397 00:13:02,440 --> 00:13:04,560 I've heard they have a huge impact on marine life 398 00:13:04,560 --> 00:13:06,040 and entire ecosystems. 399 00:13:06,040 --> 00:13:06,600 You're right. 400 00:13:06,600 --> 00:13:08,160 They're not just a pretty sight. 401 00:13:08,160 --> 00:13:08,680 Right. 402 00:13:08,680 --> 00:13:13,120 Tides play a critical role in how nutrients get distributed, 403 00:13:13,120 --> 00:13:16,240 how ocean waters mix, and even the life cycles 404 00:13:16,240 --> 00:13:18,040 of tons of marine organisms. 405 00:13:18,040 --> 00:13:18,640 Wow. 406 00:13:18,640 --> 00:13:21,560 So the moon isn't just Earth's celestial companion. 407 00:13:21,560 --> 00:13:22,200 No. 408 00:13:22,200 --> 00:13:25,160 It's a vital force shaping the planet's oceans 409 00:13:25,160 --> 00:13:26,480 and the life within them. 410 00:13:26,480 --> 00:13:29,400 You could even say that the moon's influence 411 00:13:29,400 --> 00:13:33,200 is woven into the very fabric of life on Earth. 412 00:13:33,200 --> 00:13:34,440 That's a cool way to put it. 413 00:13:34,440 --> 00:13:36,280 It's pretty profound when you think about it. 414 00:13:36,280 --> 00:13:38,680 And we can't forget that the moon is slowly 415 00:13:38,680 --> 00:13:40,080 drifting away from us. 416 00:13:40,080 --> 00:13:40,600 Right. 417 00:13:40,600 --> 00:13:41,920 We talked about that before. 418 00:13:41,920 --> 00:13:44,400 What kind of long-term impact will that have? 419 00:13:44,400 --> 00:13:47,800 I mean, is the Earth going to be OK without its moon? 420 00:13:47,800 --> 00:13:49,240 That's an important question. 421 00:13:49,240 --> 00:13:49,720 It is. 422 00:13:49,720 --> 00:13:53,680 As the moon moves further away, its gravitational pull 423 00:13:53,680 --> 00:13:55,520 on Earth weakens. 424 00:13:55,520 --> 00:13:58,400 Means the tides will become less pronounced, 425 00:13:58,400 --> 00:14:01,160 and Earth's rotation will keep slowing down. 426 00:14:01,160 --> 00:14:02,160 Oh, OK. 427 00:14:02,160 --> 00:14:04,320 Which means, you guessed it, longer days. 428 00:14:04,320 --> 00:14:05,800 Longer days sound pretty good to me. 429 00:14:05,800 --> 00:14:07,280 More time to get things done right. 430 00:14:07,280 --> 00:14:07,760 Right. 431 00:14:07,760 --> 00:14:11,520 So we'll have more time to enjoy those beach sunsets, 432 00:14:11,520 --> 00:14:12,960 even if the waves aren't as big. 433 00:14:12,960 --> 00:14:13,960 It's a trade-off. 434 00:14:13,960 --> 00:14:14,440 Yeah. 435 00:14:14,440 --> 00:14:16,200 But it's also a powerful reminder 436 00:14:16,200 --> 00:14:18,320 that nothing stays the same. 437 00:14:18,320 --> 00:14:18,840 That's true. 438 00:14:18,840 --> 00:14:20,320 Even on a cosmic scale. 439 00:14:20,320 --> 00:14:20,840 I see. 440 00:14:20,840 --> 00:14:23,280 The Earth-Moon system is always changing. 441 00:14:23,280 --> 00:14:25,880 And it's fascinating to see how these changes have influenced 442 00:14:25,880 --> 00:14:29,320 our planet's past and will continue to shape its future. 443 00:14:29,320 --> 00:14:32,320 The moon really has shaped so much of what we see around us. 444 00:14:32,320 --> 00:14:33,080 Yeah. 445 00:14:33,080 --> 00:14:35,840 Everything from our oceans to the length of our days, 446 00:14:35,840 --> 00:14:37,400 even the air we breathe. 447 00:14:37,400 --> 00:14:39,400 It's a testament to how interconnected 448 00:14:39,400 --> 00:14:40,760 the universe really is. 449 00:14:40,760 --> 00:14:41,280 It is. 450 00:14:41,280 --> 00:14:44,240 Every single object, every event, 451 00:14:44,240 --> 00:14:47,920 is part of a larger cosmic web influencing and being 452 00:14:47,920 --> 00:14:49,960 influenced by everything around it. 453 00:14:49,960 --> 00:14:51,920 It really makes you feel small, but also connected 454 00:14:51,920 --> 00:14:53,840 to something much bigger than yourself. 455 00:14:53,840 --> 00:14:57,080 That's one of the most amazing things about studying space. 456 00:14:57,080 --> 00:14:57,600 Yeah. 457 00:14:57,600 --> 00:14:59,600 It gives you that sense of wonder and connection 458 00:14:59,600 --> 00:15:01,240 to something truly grand. 459 00:15:01,240 --> 00:15:02,320 I completely agree. 460 00:15:02,320 --> 00:15:02,920 OK. 461 00:15:02,920 --> 00:15:06,240 We've covered so much ground in this deep dive. 462 00:15:06,240 --> 00:15:09,200 The moon's dramatic birth, its influence on Earth. 463 00:15:09,200 --> 00:15:11,720 We even talked about Earth's first breath. 464 00:15:11,720 --> 00:15:13,840 But I have a feeling there's more to this story. 465 00:15:13,840 --> 00:15:14,360 There is. 466 00:15:14,360 --> 00:15:14,880 Am I right? 467 00:15:14,880 --> 00:15:15,520 You are. 468 00:15:15,520 --> 00:15:18,640 There's another sign to this Earth-Moon relationship. 469 00:15:18,640 --> 00:15:23,240 And it's a bit more, let's just say, controversial. 470 00:15:23,240 --> 00:15:23,840 OK. 471 00:15:23,840 --> 00:15:25,120 Now I'm really intrigued. 472 00:15:25,120 --> 00:15:25,600 All right. 473 00:15:25,600 --> 00:15:27,280 I can't wait to hear more. 474 00:15:27,280 --> 00:15:28,720 Let's dive into that in part three. 475 00:15:28,720 --> 00:15:29,640 Sounds good to me. 476 00:15:29,640 --> 00:15:30,140 OK. 477 00:15:30,140 --> 00:15:30,880 Stay tuned. 478 00:15:30,880 --> 00:15:33,200 Welcome back to the final part of our deep dive 479 00:15:33,200 --> 00:15:36,000 into this incredible Earth-Moon relationship. 480 00:15:36,000 --> 00:15:37,920 It's been quite the journey so far. 481 00:15:37,920 --> 00:15:40,520 Last time, you hinted at a more controversial side 482 00:15:40,520 --> 00:15:41,280 of the story. 483 00:15:41,280 --> 00:15:43,080 I'm dying to know what we're getting into. 484 00:15:43,080 --> 00:15:45,200 Well, even though scientists mostly 485 00:15:45,200 --> 00:15:47,440 agree on the basics of the moon's formation 486 00:15:47,440 --> 00:15:50,040 and its effect on Earth, there are some areas 487 00:15:50,040 --> 00:15:51,360 where opinions differ. 488 00:15:51,360 --> 00:15:52,120 That makes sense. 489 00:15:52,120 --> 00:15:54,320 Sometimes those differences get pretty heated. 490 00:15:54,320 --> 00:15:56,440 I love a good scientific debate. 491 00:15:56,440 --> 00:15:57,200 Bring it on. 492 00:15:57,200 --> 00:15:57,880 OK. 493 00:15:57,880 --> 00:15:59,920 What are some of these controversial areas? 494 00:15:59,920 --> 00:16:01,960 One of the biggest debates revolves 495 00:16:01,960 --> 00:16:05,240 around the finer points of the giant impact hypothesis 496 00:16:05,240 --> 00:16:07,280 itself. 497 00:16:07,280 --> 00:16:10,200 The giant impact hypothesis. 498 00:16:10,200 --> 00:16:11,000 Remember Thea. 499 00:16:11,000 --> 00:16:11,680 Thea, right? 500 00:16:11,680 --> 00:16:14,040 That Mars-sized proto planet we talked about, 501 00:16:14,040 --> 00:16:16,280 the one that supposedly slammed into Earth. 502 00:16:16,280 --> 00:16:17,480 Of course. 503 00:16:17,480 --> 00:16:20,520 The moon's famous or infamous parent. 504 00:16:20,520 --> 00:16:21,960 Well, some scientists are starting 505 00:16:21,960 --> 00:16:25,000 to question whether Thea actually existed at all. 506 00:16:25,000 --> 00:16:25,960 Hold on. 507 00:16:25,960 --> 00:16:28,200 Are you saying that the moon's origin story might 508 00:16:28,200 --> 00:16:30,880 be based on a ghost planet? 509 00:16:30,880 --> 00:16:31,760 Maybe not a ghost. 510 00:16:31,760 --> 00:16:32,260 OK. 511 00:16:32,260 --> 00:16:33,920 But perhaps more of a phantom. 512 00:16:33,920 --> 00:16:35,160 A phantom planet. 513 00:16:35,160 --> 00:16:38,480 Some of the newer models suggest that the object that hit Earth 514 00:16:38,480 --> 00:16:41,240 was much smaller than initially thought. 515 00:16:41,240 --> 00:16:41,740 OK. 516 00:16:41,740 --> 00:16:43,000 How much smaller? 517 00:16:43,000 --> 00:16:45,840 It might have been closer to the size of the moon itself. 518 00:16:45,840 --> 00:16:48,960 So instead of a head-on collision with a planet, 519 00:16:48,960 --> 00:16:51,240 it was more of a cosmic side swipe. 520 00:16:51,240 --> 00:16:53,120 That's one possibility. 521 00:16:53,120 --> 00:16:53,620 I see. 522 00:16:53,620 --> 00:16:56,040 And if the impactor was smaller, it 523 00:16:56,040 --> 00:16:59,240 might explain why we haven't found any distinct traces 524 00:16:59,240 --> 00:17:01,600 of Thea in the Earth-moon system. 525 00:17:01,600 --> 00:17:03,600 It's like trying to find a needle in a haystack 526 00:17:03,600 --> 00:17:05,440 if you don't even know what kind of needle you're looking for. 527 00:17:05,440 --> 00:17:06,800 Exactly. 528 00:17:06,800 --> 00:17:08,920 And that leads to another point of contention, 529 00:17:08,920 --> 00:17:10,040 the composition of the moon. 530 00:17:10,040 --> 00:17:11,720 Yeah, the moon's made of cheese, right? 531 00:17:11,720 --> 00:17:13,640 Well, lunar rocks do have some things 532 00:17:13,640 --> 00:17:15,280 in common with Earth's mantle. 533 00:17:15,280 --> 00:17:15,780 Right. 534 00:17:15,780 --> 00:17:16,680 We talked about that. 535 00:17:16,680 --> 00:17:18,680 There are also some subtle differences. 536 00:17:18,680 --> 00:17:20,200 So it's not a perfect match. 537 00:17:20,200 --> 00:17:21,000 Yeah. 538 00:17:21,000 --> 00:17:23,160 Like, they're from the same family, 539 00:17:23,160 --> 00:17:25,280 but they have their own distinct personalities. 540 00:17:25,280 --> 00:17:27,280 That's the idea. 541 00:17:27,280 --> 00:17:29,160 These differences have led some scientists 542 00:17:29,160 --> 00:17:32,520 to come up with other theories to explain how the moon formed. 543 00:17:32,520 --> 00:17:33,160 Really? 544 00:17:33,160 --> 00:17:35,600 So they think maybe it wasn't a giant impact after all. 545 00:17:35,600 --> 00:17:39,040 They're not ready to completely give up on the giant impact, 546 00:17:39,040 --> 00:17:41,280 but they're exploring other possibilities too. 547 00:17:41,280 --> 00:17:42,920 OK, spill the beans. 548 00:17:42,920 --> 00:17:45,040 What are some of these alternative theories? 549 00:17:45,040 --> 00:17:47,880 Well, one idea that's gaining some traction 550 00:17:47,880 --> 00:17:49,440 is that the moon might have formed 551 00:17:49,440 --> 00:17:51,600 from multiple smaller impacts. 552 00:17:51,600 --> 00:17:52,520 Multiple impacts. 553 00:17:52,520 --> 00:17:54,840 Rather than one gigantic event. 554 00:17:54,840 --> 00:17:55,560 Wow. 555 00:17:55,560 --> 00:17:59,080 Imagine a series of collisions over millions of years. 556 00:17:59,080 --> 00:17:59,760 Oh, wow. 557 00:17:59,760 --> 00:18:02,800 Each one contributing to a growing disk of debris 558 00:18:02,800 --> 00:18:04,600 that eventually became the moon. 559 00:18:04,600 --> 00:18:06,640 So instead of one big bang, it was 560 00:18:06,640 --> 00:18:10,400 more of a slow and steady cosmic construction project. 561 00:18:10,400 --> 00:18:11,080 Exactly. 562 00:18:11,080 --> 00:18:13,720 Kind of like how Earth's atmosphere formed bit by bit. 563 00:18:13,720 --> 00:18:15,560 And this multiple impact idea could 564 00:18:15,560 --> 00:18:17,320 explain some of the differences we see 565 00:18:17,320 --> 00:18:19,360 in the composition of lunar rocks. 566 00:18:19,360 --> 00:18:22,640 So the jury's still out on exactly how the moon came to be. 567 00:18:22,640 --> 00:18:23,760 It seems that way. 568 00:18:23,760 --> 00:18:26,440 But the giant impact remains the leading contender. 569 00:18:26,440 --> 00:18:27,400 For now, it does. 570 00:18:27,400 --> 00:18:29,280 It sounds like there's still a lot of active research 571 00:18:29,280 --> 00:18:30,240 happening in this area. 572 00:18:30,240 --> 00:18:31,360 Absolutely. 573 00:18:31,360 --> 00:18:32,880 But that's the beauty of science. 574 00:18:32,880 --> 00:18:33,480 It is. 575 00:18:33,480 --> 00:18:35,040 It's always evolving. 576 00:18:35,040 --> 00:18:35,520 Right. 577 00:18:35,520 --> 00:18:38,280 New discoveries and new models can change our understanding 578 00:18:38,280 --> 00:18:41,080 and lead to new and exciting theories. 579 00:18:41,080 --> 00:18:42,680 So we're always learning something new. 580 00:18:42,680 --> 00:18:44,960 It's a journey, not a destination. 581 00:18:44,960 --> 00:18:45,640 I like that. 582 00:18:45,640 --> 00:18:46,760 I like that analogy. 583 00:18:46,760 --> 00:18:48,000 It really is. 584 00:18:48,000 --> 00:18:51,400 Like a cosmic puzzle where we're slowly 585 00:18:51,400 --> 00:18:52,600 putting the pieces together. 586 00:18:52,600 --> 00:18:53,360 Uh-huh. 587 00:18:53,360 --> 00:18:54,560 And we've come a long way. 588 00:18:54,560 --> 00:18:56,760 But there's still more pieces to find. 589 00:18:56,760 --> 00:19:00,360 Every new piece we find helps us paint a more complete picture 590 00:19:00,360 --> 00:19:02,280 of our solar system's history. 591 00:19:02,280 --> 00:19:04,600 This has been an incredible deep dive. 592 00:19:04,600 --> 00:19:05,280 It has been. 593 00:19:05,280 --> 00:19:07,720 We've explored the moon's explosive birth. 594 00:19:07,720 --> 00:19:08,920 Yeah, it was pretty dramatic. 595 00:19:08,920 --> 00:19:10,720 Its influence on Earth. 596 00:19:10,720 --> 00:19:12,600 Profound, really. 597 00:19:12,600 --> 00:19:14,600 And even dove into some of the controversies 598 00:19:14,600 --> 00:19:15,560 about its origins. 599 00:19:15,560 --> 00:19:18,000 Yeah, always interesting to see where opinions differ. 600 00:19:18,000 --> 00:19:20,240 It's amazing to think about all the things we've learned 601 00:19:20,240 --> 00:19:22,440 about our celestial companion. 602 00:19:22,440 --> 00:19:25,040 It's been a fantastic journey through billions 603 00:19:25,040 --> 00:19:26,480 of years of cosmic history. 604 00:19:26,480 --> 00:19:27,280 It really has. 605 00:19:27,280 --> 00:19:30,640 Full of awe, beauty, and a little bit of mystery. 606 00:19:30,640 --> 00:19:32,520 The best part is that there's still so much 607 00:19:32,520 --> 00:19:34,200 left to explore and discover. 608 00:19:34,200 --> 00:19:35,880 That's what keeps science going. 609 00:19:35,880 --> 00:19:36,360 It does. 610 00:19:36,360 --> 00:19:38,960 There's always something new to learn, a new question to ask. 611 00:19:38,960 --> 00:19:42,000 So to all our listeners out there, keep looking up, 612 00:19:42,000 --> 00:19:44,360 stay curious, and never stop exploring 613 00:19:44,360 --> 00:19:45,880 the wonders of the cosmos. 614 00:19:45,880 --> 00:19:48,440 And don't forget to subscribe to Cosmos in a Pod 615 00:19:48,440 --> 00:19:51,000 and check out our YouTube channel for more deep dives 616 00:19:51,000 --> 00:19:52,960 into the universe's mysteries. 617 00:19:52,960 --> 00:20:04,600 Thanks for joining us.