1 00:00:00,000 --> 00:00:02,440 Ever get that feeling, you know, when you look up at the night sky? 2 00:00:02,760 --> 00:00:04,400 Like something's calling you out there. 3 00:00:05,080 --> 00:00:07,520 Beyond those constellations we know so well. 4 00:00:07,560 --> 00:00:07,840 Yeah. 5 00:00:07,880 --> 00:00:09,040 Well, that's the Milky Way calling. 6 00:00:09,040 --> 00:00:10,280 That's our galactic home. 7 00:00:10,360 --> 00:00:10,920 Yeah. 8 00:00:11,000 --> 00:00:14,800 Billions of stars, trillions of planets swirling gas clouds. 9 00:00:15,280 --> 00:00:15,960 It's amazing. 10 00:00:15,960 --> 00:00:18,960 A whole universe just crammed into a single spiral. 11 00:00:19,000 --> 00:00:19,960 I know, right? 12 00:00:20,200 --> 00:00:24,240 And today we're strapping in for a journey across this cosmic expanse. 13 00:00:24,840 --> 00:00:25,520 Buckle up. 14 00:00:25,520 --> 00:00:29,680 Welcome to Cosmos in a Podspace and Astronomy series. 15 00:00:30,640 --> 00:00:31,520 It's so cool, right? 16 00:00:31,520 --> 00:00:33,960 Because we're not just looking at static points of light. 17 00:00:34,040 --> 00:00:34,400 Right. 18 00:00:34,400 --> 00:00:38,280 It's a living galaxy, you know, breathing with stories constantly 19 00:00:38,280 --> 00:00:41,200 unfolding births, deaths, collisions. 20 00:00:41,240 --> 00:00:41,600 Wow. 21 00:00:41,640 --> 00:00:45,680 It's drama on a scale that makes Earth's history look like a blink. 22 00:00:45,800 --> 00:00:47,720 So let's unpack that drama, shall we? 23 00:00:47,760 --> 00:00:48,320 Let's do it. 24 00:00:48,360 --> 00:00:50,160 Starting close to home Alpha Centauri. 25 00:00:50,200 --> 00:00:50,920 Yeah. 26 00:00:50,960 --> 00:00:53,240 That's the system everyone's buzzing about these days, right? 27 00:00:53,240 --> 00:00:58,000 Right, our closest stellar neighbor, just over four light years away. 28 00:00:58,040 --> 00:00:58,440 Wow. 29 00:00:58,480 --> 00:01:01,320 And it's not just one star, but three dancing around each other. 30 00:01:01,480 --> 00:01:04,440 Alpha Centauri A and B, both pretty similar to our sun. 31 00:01:04,440 --> 00:01:09,240 And then there's Proxima Centauri, a much smaller, cooler red dwarf. 32 00:01:09,280 --> 00:01:10,320 Proxima Centauri. 33 00:01:10,480 --> 00:01:13,120 Now, didn't they find a planet there that might be habitable? 34 00:01:13,160 --> 00:01:13,600 They did. 35 00:01:13,640 --> 00:01:16,720 It's called Proxima Centauri B and it orbits in the habitable zone. 36 00:01:16,800 --> 00:01:17,120 Okay. 37 00:01:17,160 --> 00:01:21,480 Meaning it's the right distance from its star for liquid water to possibly exist. 38 00:01:21,520 --> 00:01:22,360 It's so cool. 39 00:01:22,360 --> 00:01:23,920 But here's the thing. 40 00:01:23,960 --> 00:01:28,720 Red dwarf stars, they're kind of notorious for powerful flares, these bursts of 41 00:01:28,720 --> 00:01:32,120 radiation that could sterilize any planets close by. 42 00:01:32,160 --> 00:01:32,520 Oh. 43 00:01:32,800 --> 00:01:36,560 So whether life could actually survive there is a big question mark. 44 00:01:36,600 --> 00:01:36,840 Okay. 45 00:01:36,840 --> 00:01:39,120 So maybe not the best place to look for a vacation home. 46 00:01:39,160 --> 00:01:39,720 Maybe not. 47 00:01:39,960 --> 00:01:41,520 What about Barnard's star? 48 00:01:42,560 --> 00:01:43,680 I remember that name for Centauri. 49 00:01:43,720 --> 00:01:44,840 Another red dwarf. 50 00:01:45,240 --> 00:01:46,640 This one's a speed demon though. 51 00:01:46,680 --> 00:01:47,120 Really? 52 00:01:47,160 --> 00:01:47,400 Yeah. 53 00:01:47,440 --> 00:01:50,360 Moving across the sky faster than any other star we see. 54 00:01:50,400 --> 00:01:50,960 Wow. 55 00:01:50,960 --> 00:01:53,280 And it has a planet too, Barnard's star B. 56 00:01:53,800 --> 00:01:54,960 It's what we call a super earth. 57 00:01:55,000 --> 00:01:55,680 Super earth. 58 00:01:55,720 --> 00:01:56,080 Yeah. 59 00:01:56,120 --> 00:01:59,800 Meaning it's bigger than our planet, but smaller than a gas giant. 60 00:01:59,840 --> 00:02:00,160 Okay. 61 00:02:00,200 --> 00:02:01,240 Is this one habitable? 62 00:02:02,080 --> 00:02:04,640 It's possible, but in a way we don't usually imagine. 63 00:02:04,880 --> 00:02:10,120 The planet's surface is probably incredibly cold, around mega 168 degrees Celsius. 64 00:02:10,160 --> 00:02:10,680 Yeah. 65 00:02:10,720 --> 00:02:15,680 But some scientists think there could be a subsurface ocean warmed by the planet's 66 00:02:15,680 --> 00:02:16,680 internal heat. 67 00:02:17,040 --> 00:02:20,320 It's a good reminder that life might exist in places we wouldn't expect even 68 00:02:20,320 --> 00:02:21,400 in our own backyard. 69 00:02:21,440 --> 00:02:22,600 Subsurface oceans. 70 00:02:22,840 --> 00:02:24,680 I mean, that's where things get really interesting. 71 00:02:24,720 --> 00:02:26,880 What kind of life could evolve in a place like that? 72 00:02:26,920 --> 00:02:27,520 Yeah, I know. 73 00:02:27,520 --> 00:02:28,920 It's wild to think about. 74 00:02:29,600 --> 00:02:33,120 We can only speculate really, but it opens up this whole new realm of 75 00:02:33,120 --> 00:02:34,000 possibilities. 76 00:02:34,040 --> 00:02:38,840 Imagine creatures adapted to eternal darkness, thriving on geothermal energy 77 00:02:38,840 --> 00:02:39,720 instead of sunlight. 78 00:02:40,240 --> 00:02:40,720 Wow. 79 00:02:40,760 --> 00:02:43,800 It really challenges our very definition of habitable. 80 00:02:43,840 --> 00:02:44,600 It really does. 81 00:02:44,640 --> 00:02:47,320 Speaking of backyard wonders, what about Sirius? 82 00:02:47,600 --> 00:02:48,240 Oh yeah. 83 00:02:48,240 --> 00:02:50,440 That's the brightest star in our sky, isn't it? 84 00:02:50,480 --> 00:02:50,880 It is. 85 00:02:50,880 --> 00:02:54,280 It's another binary system, but much different from Alpha Centauri. 86 00:02:54,320 --> 00:02:55,120 How so? 87 00:02:55,160 --> 00:02:59,560 Well, Sirius A is a massive blue-white star about twice the size of our sun. 88 00:02:59,600 --> 00:03:00,000 Wow. 89 00:03:00,200 --> 00:03:04,840 And its companion, Sirius B, is a white dwarf, the dense collapsed core of a 90 00:03:04,840 --> 00:03:06,760 star that's already gone through its life cycle. 91 00:03:06,800 --> 00:03:07,560 Oh, wow. 92 00:03:07,600 --> 00:03:11,080 So it's like a cosmic graveyard orbiting a blazing inferno. 93 00:03:11,120 --> 00:03:12,120 Kind of, yeah. 94 00:03:12,640 --> 00:03:14,200 I'm guessing no planets there. 95 00:03:14,240 --> 00:03:15,720 None that we've found yet. 96 00:03:16,160 --> 00:03:17,920 But that doesn't mean they're not there. 97 00:03:17,920 --> 00:03:20,360 We're always refining our methods of detection. 98 00:03:20,400 --> 00:03:20,800 Right. 99 00:03:20,840 --> 00:03:24,920 Who knows what surprises are lurking around even the most familiar stars. 100 00:03:25,240 --> 00:03:27,200 So we've done a quick tour of our neighborhood. 101 00:03:27,240 --> 00:03:27,440 Yeah. 102 00:03:27,480 --> 00:03:30,000 Now let's venture a bit further out, shall we? 103 00:03:30,040 --> 00:03:30,600 Let's go. 104 00:03:30,640 --> 00:03:33,440 What are some of the more exotic exoplanets we've discovered? 105 00:03:33,480 --> 00:03:36,600 Oh, we're talking about planets that push the boundaries of what we thought was 106 00:03:36,600 --> 00:03:37,200 possible. 107 00:03:37,240 --> 00:03:37,600 Right. 108 00:03:37,640 --> 00:03:40,200 Take Wolf 1061C, for example. 109 00:03:40,240 --> 00:03:40,440 Okay. 110 00:03:40,480 --> 00:03:44,600 It's a super Earth orbiting a red dwarf star, and it's really caught our 111 00:03:44,600 --> 00:03:47,920 attention because it sits right in the habitable zone. 112 00:03:47,960 --> 00:03:49,800 Oh, so another potential water world. 113 00:03:49,840 --> 00:03:50,520 Possibly. 114 00:03:50,560 --> 00:03:52,760 But here's what's really interesting. 115 00:03:52,800 --> 00:03:56,560 Red dwarfs have much smaller habitable zones than our sun. 116 00:03:56,600 --> 00:03:56,920 Oh. 117 00:03:56,960 --> 00:04:00,840 That means planets like Wolf 1061C are tidally locked. 118 00:04:00,880 --> 00:04:01,920 Tidally locked. 119 00:04:01,960 --> 00:04:05,480 One side always faces the star, the other always faces away. 120 00:04:05,520 --> 00:04:06,160 Oh, wow. 121 00:04:06,200 --> 00:04:09,440 So you'd have like a permanent day side and a permanent night side. 122 00:04:09,480 --> 00:04:10,440 Exactly. 123 00:04:10,440 --> 00:04:16,920 Imagine the extremes scorching heat on one side, eternal darkness on the other. 124 00:04:16,960 --> 00:04:17,960 That's wild. 125 00:04:18,000 --> 00:04:21,840 Makes you wonder what kind of weather patterns, you know, what kind of life 126 00:04:21,880 --> 00:04:23,440 could even exist in such a place? 127 00:04:23,480 --> 00:04:25,760 Yeah, it sounds like a world of stark contrasts. 128 00:04:25,800 --> 00:04:27,280 Anything even wilder out there? 129 00:04:27,320 --> 00:04:27,880 Absolutely. 130 00:04:27,920 --> 00:04:30,160 How about K2-141b? 131 00:04:30,200 --> 00:04:32,160 Now, this is truly bizarre. 132 00:04:32,200 --> 00:04:33,040 Okay, I'm ready. 133 00:04:33,080 --> 00:04:37,640 Imagine a planet where one side is covered in a magma ocean. 134 00:04:37,680 --> 00:04:39,000 A magma ocean. 135 00:04:39,000 --> 00:04:43,160 Molten rock reaching temperatures over 3000 degrees Celsius. 136 00:04:43,200 --> 00:04:44,000 Oh, my goodness. 137 00:04:44,040 --> 00:04:47,000 And the other side is locked in freezing darkness. 138 00:04:47,040 --> 00:04:48,320 Hold on, a magma ocean. 139 00:04:48,360 --> 00:04:49,440 That's insane. 140 00:04:49,480 --> 00:04:50,880 And it gets even weirder. 141 00:04:50,920 --> 00:04:51,320 Okay. 142 00:04:51,360 --> 00:04:55,320 The intense heat on the day side causes rocks to vaporize, 143 00:04:55,360 --> 00:04:58,480 and those vapors are carried by supersonic winds to the night side 144 00:04:58,520 --> 00:05:01,400 where they cool, condense and rain down as molten metal. 145 00:05:01,440 --> 00:05:02,120 Metallic rain. 146 00:05:02,160 --> 00:05:02,920 Metallic rain. 147 00:05:02,960 --> 00:05:04,640 It sounds like something straight out of science fiction. 148 00:05:04,680 --> 00:05:08,080 It does, but it highlights this incredible diversity of planets out there. 149 00:05:08,080 --> 00:05:12,600 And then there's GJ-1214b, a planet that takes water world to a whole new level. 150 00:05:12,640 --> 00:05:16,600 Okay, so, I mean, isn't a water world just a lot of water? 151 00:05:16,640 --> 00:05:17,120 Yeah. 152 00:05:17,160 --> 00:05:20,440 But GJ-1214b is thought to be completely covered in water 153 00:05:20,480 --> 00:05:22,600 with an ocean hundreds of kilometers deep. 154 00:05:22,640 --> 00:05:23,200 Wow. 155 00:05:23,240 --> 00:05:29,280 No continents, no islands, just endless water beneath a steamy, hazy sky. 156 00:05:29,320 --> 00:05:32,240 We're not even sure where the ocean ends and the atmosphere begins. 157 00:05:32,280 --> 00:05:34,440 So not exactly a place for beach combing. 158 00:05:34,480 --> 00:05:35,200 Probably not. 159 00:05:35,200 --> 00:05:39,240 These extreme worlds, are they rare or is this what's normal out there? 160 00:05:39,280 --> 00:05:41,960 That's a question we're still trying to answer, you know? 161 00:05:42,000 --> 00:05:43,680 The more exoplanets we find, 162 00:05:43,720 --> 00:05:47,600 the more we realize how limited our Earth-centric view is. 163 00:05:47,640 --> 00:05:48,160 Right. 164 00:05:48,200 --> 00:05:52,240 Maybe these seemingly bizarre worlds are more common than we think. 165 00:05:52,280 --> 00:05:54,280 It's mind-boggling to think about, 166 00:05:54,320 --> 00:05:58,840 okay, we've explored scorching hot planets, potential water worlds. 167 00:05:58,880 --> 00:06:00,800 Now, what about something a bit darker? 168 00:06:00,840 --> 00:06:01,320 Ooh. 169 00:06:01,360 --> 00:06:02,240 Let's talk black holes. 170 00:06:02,280 --> 00:06:02,840 All right. 171 00:06:02,880 --> 00:06:04,320 The ultimate cosmic enigmas. 172 00:06:04,320 --> 00:06:09,080 Regions of space-time where gravity is so strong that nothing, not even light, can escape. 173 00:06:09,120 --> 00:06:11,480 And we have one right in our own backyard, so to speak. 174 00:06:11,520 --> 00:06:11,960 Right. 175 00:06:12,000 --> 00:06:15,320 You mean V6 weeks of Monteserratus, the closest black hole to Earth? 176 00:06:15,360 --> 00:06:16,080 That's the one. 177 00:06:16,120 --> 00:06:20,280 A stellar mass black hole about 3,300 light-years away. 178 00:06:20,320 --> 00:06:24,680 It's part of a binary system slowly pulling matter from its companion star. 179 00:06:24,720 --> 00:06:25,240 Oh, wow. 180 00:06:25,280 --> 00:06:28,680 This matter forms a swirling disk of superheated gas 181 00:06:28,720 --> 00:06:31,400 glowing brightly as it spirals into the black hole. 182 00:06:31,400 --> 00:06:34,320 It sounds almost beautiful in a terrifying kind of way. 183 00:06:34,360 --> 00:06:34,760 It is. 184 00:06:34,800 --> 00:06:36,520 It's a delicate dance of destruction. 185 00:06:36,560 --> 00:06:36,880 Right. 186 00:06:36,920 --> 00:06:42,080 But it pales in comparison to the monster lurking at the heart of our galaxy, Sagittarius, 187 00:06:42,120 --> 00:06:46,680 the supermassive black hole that holds the entire Milky Way in its gravitational grip. 188 00:06:46,720 --> 00:06:51,680 I remember seeing that image of Sagittarius A, the blurry orange doughnut. 189 00:06:51,720 --> 00:06:54,560 It's hard to believe something so massive can be so compact. 190 00:06:54,600 --> 00:06:55,920 It is mind-boggling. 191 00:06:55,920 --> 00:07:01,720 Sagittarius A packs a mass of over 4 million suns into a space smaller than our solar system. 192 00:07:01,760 --> 00:07:02,280 Wow. 193 00:07:02,320 --> 00:07:05,040 We're talking about an object that warps space and time itself. 194 00:07:05,080 --> 00:07:07,120 So what's it like near a supermassive black hole? 195 00:07:07,160 --> 00:07:09,280 Is it just darkness or is there something more going on? 196 00:07:09,320 --> 00:07:12,720 It's a region of intense activity, a chaotic mix of stars, 197 00:07:12,760 --> 00:07:16,080 gas and dust swirling around the black hole at incredible speeds. 198 00:07:16,120 --> 00:07:21,040 Some stars like S62 orbit so close they reach speeds of 6.7% the speed of light. 199 00:07:21,080 --> 00:07:23,120 I can't even comprehend that kind of speed. 200 00:07:23,160 --> 00:07:24,400 Yeah, it's hard to wrap your head around. 201 00:07:24,440 --> 00:07:24,720 Yeah. 202 00:07:24,720 --> 00:07:27,840 And beyond these daredevil stars, there's this central molecular zone, 203 00:07:27,880 --> 00:07:30,760 a region further out where new stars are being born. 204 00:07:30,800 --> 00:07:33,400 It's a reminder that even in the most extreme environments, 205 00:07:33,440 --> 00:07:36,040 creation and destruction go hand in hand. 206 00:07:36,080 --> 00:07:43,640 So the Galactic Center is this wild mix of intense gravity, superfast stars and stellar nurseries. 207 00:07:43,680 --> 00:07:45,520 What's next on our cosmic road trip? 208 00:07:45,560 --> 00:07:47,680 Well, we've explored the heart of the Milky Way now. 209 00:07:47,720 --> 00:07:51,440 Let's zoom out a bit and take a look at the grand structure of our galaxy. 210 00:07:51,480 --> 00:07:53,000 We live in the galactic disk, right? 211 00:07:53,000 --> 00:07:56,800 Right, the flat rotating disk of stars, gas and dust 212 00:07:56,840 --> 00:07:59,240 that makes up the most visible part of the Milky Way. 213 00:07:59,280 --> 00:08:00,920 It's like a giant cosmic pizza. 214 00:08:00,960 --> 00:08:01,880 I like that. 215 00:08:01,920 --> 00:08:05,680 And our solar system sits on one of the spiral arms, the Orion arm. 216 00:08:05,720 --> 00:08:06,120 OK. 217 00:08:06,160 --> 00:08:10,680 It's one of several major arms, like the Perseus arm and the Scutum Centaurus arm, 218 00:08:10,720 --> 00:08:13,720 which are regions of intense star formation. 219 00:08:13,760 --> 00:08:17,560 I've always been curious about those dark patches we see in the Milky Way. 220 00:08:17,600 --> 00:08:18,680 What are those? 221 00:08:18,680 --> 00:08:23,400 Oh, those are dust lanes regions where dense clouds of interstellar dust 222 00:08:23,440 --> 00:08:25,680 block the light from stars behind them. 223 00:08:25,720 --> 00:08:28,280 One prominent example is the Great Rift, 224 00:08:28,320 --> 00:08:32,040 a dark band that stretches across a significant portion of the Milky Way. 225 00:08:32,080 --> 00:08:34,920 So those dust lanes are actually hiding even more stars. 226 00:08:34,960 --> 00:08:35,720 Exactly. 227 00:08:35,760 --> 00:08:37,440 And these clouds aren't just blocking light. 228 00:08:37,480 --> 00:08:40,160 They're also the raw material for future star formation. 229 00:08:40,200 --> 00:08:40,560 Whoa. 230 00:08:40,600 --> 00:08:44,680 They're rich in hydrogen and other molecules, the building blocks of stars and planets. 231 00:08:44,720 --> 00:08:47,640 It's amazing to think that even in those dark patches, 232 00:08:47,640 --> 00:08:49,760 new stars and planets are being born. 233 00:08:49,800 --> 00:08:51,560 What lies beyond the disk? 234 00:08:51,600 --> 00:08:53,880 Beyond the disk is the Galactic Halo, 235 00:08:53,920 --> 00:08:57,160 a vast spherical region that surrounds the disk. 236 00:08:57,200 --> 00:09:00,360 It's much less dense, but it's home to some fascinating objects 237 00:09:00,400 --> 00:09:02,360 like ancient globular clusters. 238 00:09:02,400 --> 00:09:03,200 Globular clusters. 239 00:09:03,240 --> 00:09:06,400 They're tightly packed spherical collections of hundreds of thousands, 240 00:09:06,440 --> 00:09:11,000 even millions of stars, some of the oldest stars in the Milky Way. 241 00:09:11,040 --> 00:09:13,560 Imagine these ancient swarms of stars 242 00:09:13,600 --> 00:09:16,560 orbiting the galactic center like bees around a hive. 243 00:09:16,560 --> 00:09:18,400 And there are also these stellar streams, right? 244 00:09:18,440 --> 00:09:20,480 I remember reading about the Sagittarius stream. 245 00:09:20,520 --> 00:09:21,120 Oh, yeah. 246 00:09:21,160 --> 00:09:25,080 The Sagittarius stream is a long ribbon-like structure of stars 247 00:09:25,120 --> 00:09:26,960 that wraps around the Milky Way. 248 00:09:27,000 --> 00:09:29,840 It's believed to be the remnants of a dwarf galaxy 249 00:09:29,880 --> 00:09:32,720 that was captured and torn apart by the Milky Way's gravity. 250 00:09:32,760 --> 00:09:35,280 So the Milky Way is kind of a galactic cannibal. 251 00:09:35,320 --> 00:09:36,640 In a way, yes. 252 00:09:36,680 --> 00:09:40,160 Large galaxies often grow by absorbing smaller ones. 253 00:09:40,200 --> 00:09:42,520 It's a reminder that even on a galactic scale, 254 00:09:42,560 --> 00:09:45,560 there's a constant struggle for survival and dominance. 255 00:09:45,560 --> 00:09:47,120 And then there's the Dark Halo, 256 00:09:47,160 --> 00:09:49,520 this mysterious region that we can't see directly. 257 00:09:49,560 --> 00:09:51,000 Right, the Dark Halo. 258 00:09:51,040 --> 00:09:53,600 It's thought to be a massive halo of dark matter 259 00:09:53,640 --> 00:09:56,560 that extends far beyond the visible galaxy. 260 00:09:56,600 --> 00:09:58,240 We can't see dark matter directly, 261 00:09:58,280 --> 00:10:00,840 but we know it's there because of its gravitational effects 262 00:10:00,880 --> 00:10:01,840 on the visible matter. 263 00:10:01,880 --> 00:10:03,120 So even though we can't see it, 264 00:10:03,160 --> 00:10:05,080 it's holding the entire galaxy together. 265 00:10:05,120 --> 00:10:06,840 That's the current understanding. 266 00:10:06,880 --> 00:10:09,960 Dark matter makes up the vast majority of the Milky Way's mass, 267 00:10:10,000 --> 00:10:13,640 and it plays a crucial role in the galaxy's structure and evolution. 268 00:10:13,640 --> 00:10:16,120 Wow, it's incredible to think that we're surrounded 269 00:10:16,160 --> 00:10:18,120 by this invisible, massive halo. 270 00:10:18,160 --> 00:10:21,760 What stands out to you from this whirlwind tour of the Milky Way? 271 00:10:21,800 --> 00:10:25,160 What strikes me is the sheer scale and diversity. 272 00:10:25,200 --> 00:10:29,000 We tend to think of planets and stars as being somewhat uniform, 273 00:10:29,040 --> 00:10:32,440 but the reality is far more bizarre and wonderful. 274 00:10:32,480 --> 00:10:35,160 From magma oceans to super-Earths, 275 00:10:35,200 --> 00:10:37,760 from black holes to stellar streams, 276 00:10:37,800 --> 00:10:40,040 the Milky Way is a cosmic tapestry 277 00:10:40,080 --> 00:10:43,000 woven with threads of wonder and destruction. 278 00:10:43,000 --> 00:10:45,000 It's certainly been an eye-opening journey so far. 279 00:10:45,040 --> 00:10:46,040 Yeah. 280 00:10:46,080 --> 00:10:47,680 But there's so much more to explore, 281 00:10:47,720 --> 00:10:50,760 so much more to learn about our galactic home. 282 00:10:50,800 --> 00:10:54,440 Stay tuned for part two of our deep dive into the Milky Way, 283 00:10:54,480 --> 00:10:57,120 where we'll delve deeper into some of the most intriguing objects 284 00:10:57,160 --> 00:10:59,200 and phenomena we've encountered on our journey. 285 00:10:59,240 --> 00:11:00,440 Sounds good. I can't wait. 286 00:11:00,480 --> 00:11:01,720 Me neither. 287 00:11:01,760 --> 00:11:04,280 Welcome back to our cosmic voyage through the Milky Way. 288 00:11:04,320 --> 00:11:06,560 Last time, we journeyed from our stellar neighbors 289 00:11:06,600 --> 00:11:08,640 all the way to the galactic halo, 290 00:11:08,680 --> 00:11:11,480 encountering black holes and star streams along the way. 291 00:11:11,520 --> 00:11:12,720 It's amazing, isn't it? 292 00:11:12,720 --> 00:11:15,640 It really gave us a sense of the Milky Way's vastness and diversity. 293 00:11:15,680 --> 00:11:16,680 Absolutely. 294 00:11:16,720 --> 00:11:18,280 Today, I'm excited to dive deeper 295 00:11:18,320 --> 00:11:22,400 into one of the most captivating areas of modern astronomy, exoplanets. 296 00:11:22,440 --> 00:11:23,520 Ooh, yes. 297 00:11:23,560 --> 00:11:25,680 These worlds orbiting other stars 298 00:11:25,720 --> 00:11:28,320 have captured our imaginations for decades. 299 00:11:28,360 --> 00:11:29,360 For sure. 300 00:11:29,400 --> 00:11:32,440 And what we've learned so far is that the universe is far stranger 301 00:11:32,480 --> 00:11:34,320 and more wonderful than we ever imagined. 302 00:11:34,360 --> 00:11:35,360 It really is. 303 00:11:35,400 --> 00:11:37,800 We touched on some pretty mind-blowing examples last time. 304 00:11:37,840 --> 00:11:38,840 Yeah. 305 00:11:38,880 --> 00:11:39,960 Like K2141b. 306 00:11:40,000 --> 00:11:41,000 Oh, yeah. 307 00:11:41,000 --> 00:11:43,240 It's magma ocean and metallic rain. 308 00:11:43,280 --> 00:11:48,200 K2141b is a perfect example of how extreme exoplanets can get. 309 00:11:48,240 --> 00:11:50,200 It's tidally locked to its star. 310 00:11:50,240 --> 00:11:51,240 Right. 311 00:11:51,280 --> 00:11:54,240 Meaning one side always faces that scorching heat 312 00:11:54,280 --> 00:11:57,440 while the other is shrouded in eternal darkness. 313 00:11:57,480 --> 00:12:00,480 What are the implications of a planet being tidally locked like that? 314 00:12:00,520 --> 00:12:02,080 Does it affect its habitability? 315 00:12:02,120 --> 00:12:04,960 It definitely creates some extreme conditions, you know? 316 00:12:05,000 --> 00:12:09,000 The temperature difference between the two sides would be enormous, 317 00:12:09,000 --> 00:12:12,200 leading to some truly bizarre weather patterns. 318 00:12:12,240 --> 00:12:16,160 While we wouldn't expect to find life as we know it on K2141b, 319 00:12:16,200 --> 00:12:20,000 it does make us rethink our definition of what a habitable planet could be. 320 00:12:20,040 --> 00:12:22,480 So even in these seemingly hostile environments, 321 00:12:22,520 --> 00:12:23,920 there's still so much to learn. 322 00:12:23,960 --> 00:12:25,240 Absolutely. 323 00:12:25,280 --> 00:12:28,560 Each exoplanet we discover, no matter how strange it seems, 324 00:12:28,600 --> 00:12:30,880 challenges our preconceived notions 325 00:12:30,920 --> 00:12:33,120 and pushes the boundaries of our understanding. 326 00:12:33,160 --> 00:12:35,880 We also talked about GJ 1214b, 327 00:12:35,920 --> 00:12:38,160 a planet that's basically a giant water balloon. 328 00:12:38,160 --> 00:12:39,560 Ah, yes. 329 00:12:39,600 --> 00:12:43,360 GJ 1214b, a fascinating example of an ocean world. 330 00:12:43,400 --> 00:12:44,400 Totally. 331 00:12:44,440 --> 00:12:46,400 We believe it's entirely covered in water, 332 00:12:46,440 --> 00:12:49,240 with an ocean hundreds of kilometers deep, 333 00:12:49,280 --> 00:12:52,200 and its atmosphere is so thick and steamy 334 00:12:52,240 --> 00:12:55,640 that it's difficult to tell where the water ends and the sky begins. 335 00:12:55,680 --> 00:12:58,600 It makes you wonder what kind of life could exist in such a watery world. 336 00:12:58,640 --> 00:13:02,600 It's a question that sparks the imagination, for sure. 337 00:13:02,640 --> 00:13:07,080 Could there be creatures adapted to crushing pressures and eternal darkness, 338 00:13:07,080 --> 00:13:09,800 like swimming in the depths of that alien ocean? 339 00:13:09,840 --> 00:13:11,920 It's a reminder that life might find a way, 340 00:13:11,960 --> 00:13:13,880 even in the most unexpected places. 341 00:13:13,920 --> 00:13:15,080 Absolutely. 342 00:13:15,120 --> 00:13:17,960 OK, so we've explored some of the more extreme ends of the spectrum. 343 00:13:18,000 --> 00:13:19,000 We have. 344 00:13:19,040 --> 00:13:21,760 What about planets that are more Earth-like? 345 00:13:21,800 --> 00:13:23,000 Have we found any yet? 346 00:13:23,040 --> 00:13:24,600 The search for Earth 2.0 347 00:13:24,640 --> 00:13:27,320 is one of the most exciting frontiers in astronomy. 348 00:13:27,360 --> 00:13:28,360 I bet. 349 00:13:28,400 --> 00:13:30,560 We found a number of intriguing candidates. 350 00:13:30,600 --> 00:13:31,600 Oh, really? 351 00:13:31,640 --> 00:13:33,600 Planets that are similar in size and mass to Earth 352 00:13:33,640 --> 00:13:35,880 and orbit within the habitable zone of their stars. 353 00:13:35,880 --> 00:13:37,840 You mentioned habitable zones before. 354 00:13:37,880 --> 00:13:39,400 Can you explain exactly what that means? 355 00:13:39,440 --> 00:13:40,440 Sure. 356 00:13:40,480 --> 00:13:42,680 The habitable zone, also known as the Goldilocks zone, 357 00:13:42,720 --> 00:13:44,120 is the region around a star. 358 00:13:44,160 --> 00:13:45,160 OK. 359 00:13:45,200 --> 00:13:48,520 Where temperatures are just right for liquid water to exist on a planet's surface. 360 00:13:48,560 --> 00:13:50,120 Not too hot, not too cold, 361 00:13:50,160 --> 00:13:52,560 just right for the potential for life as we know it. 362 00:13:52,600 --> 00:13:54,600 So if a planet is in the habitable zone, 363 00:13:54,640 --> 00:13:56,920 does that mean it's definitely habitable? 364 00:13:56,960 --> 00:13:58,120 Not necessarily. 365 00:13:58,160 --> 00:14:01,040 While being in the habitable zone is a good starting point, 366 00:14:01,080 --> 00:14:04,520 there are many other factors that can influence a planet's habitability. 367 00:14:04,560 --> 00:14:05,560 Like what? 368 00:14:05,560 --> 00:14:09,560 Its atmosphere, its magnetic field, and the activity of its star. 369 00:14:09,600 --> 00:14:11,880 So it's not as simple as just finding a planet 370 00:14:11,920 --> 00:14:13,320 at the right distance from its star. 371 00:14:13,360 --> 00:14:14,480 No, it's not. 372 00:14:14,520 --> 00:14:16,600 There's a complex interplay of factors 373 00:14:16,640 --> 00:14:19,120 that determine whether a planet can support life. 374 00:14:19,160 --> 00:14:22,480 But finding planets in the habitable zone is a crucial step 375 00:14:22,520 --> 00:14:25,160 in our search for other worlds that might harbor life. 376 00:14:25,200 --> 00:14:29,480 What are some of the most promising Earth-like candidates we've found so far? 377 00:14:29,520 --> 00:14:33,720 One intriguing planet is Wolf 1061c, a super-Earth, 378 00:14:33,720 --> 00:14:37,520 orbiting a red dwarf star just 14 light-years away. 379 00:14:37,560 --> 00:14:41,400 It's one of the closest potentially habitable exoplanets we know of. 380 00:14:41,440 --> 00:14:45,000 Being so close, does that mean we could actually study it in detail? 381 00:14:45,040 --> 00:14:46,840 With the next generation of telescopes, 382 00:14:46,880 --> 00:14:51,400 we hope to be able to study the atmospheres of planets like Wolf 1061c. 383 00:14:51,440 --> 00:14:52,440 Oh, wow. 384 00:14:52,480 --> 00:14:55,400 Looking for signs of gases that might indicate the presence of life. 385 00:14:55,440 --> 00:14:56,760 That's incredible. 386 00:14:56,800 --> 00:14:58,920 What other Earth-like planets are on our radar? 387 00:14:58,960 --> 00:15:03,360 Another interesting candidate is Gliese 667 cc, 388 00:15:03,360 --> 00:15:08,400 a super-Earth orbiting a red dwarf star about 22 light-years away. 389 00:15:08,440 --> 00:15:11,160 It's also located within the habitable zone 390 00:15:11,200 --> 00:15:14,280 and could potentially have liquid water on its surface. 391 00:15:14,320 --> 00:15:15,920 It seems like we're finding more and more 392 00:15:15,960 --> 00:15:18,080 of these potentially habitable planets every year. 393 00:15:18,120 --> 00:15:20,360 We are. With advancements in technology, 394 00:15:20,400 --> 00:15:24,200 our ability to detect and study exoplanets is rapidly improving. 395 00:15:24,240 --> 00:15:26,880 It's an incredibly exciting time to be involved in this field. 396 00:15:26,920 --> 00:15:29,440 So we've talked about planets with magma oceans, 397 00:15:29,480 --> 00:15:32,960 water worlds, and potentially habitable super-Earths. 398 00:15:32,960 --> 00:15:33,960 Yeah. 399 00:15:34,000 --> 00:15:36,440 It seems like the possibilities are truly endless. 400 00:15:36,480 --> 00:15:39,440 They are. And as we continue to explore the Milky Way, 401 00:15:39,480 --> 00:15:42,760 we're bound to discover even more bizarre and wonderful worlds 402 00:15:42,800 --> 00:15:45,280 that challenge our understanding of what's possible. 403 00:15:45,320 --> 00:15:49,160 It makes you realize just how much we still don't know about the universe. 404 00:15:49,200 --> 00:15:50,200 It really does. 405 00:15:50,240 --> 00:15:52,480 And how much there is left to explore. 406 00:15:52,520 --> 00:15:54,240 We've covered a lot of ground in this episode. 407 00:15:54,280 --> 00:15:55,280 We have. 408 00:15:55,320 --> 00:15:58,600 From scorching hot planets to potentially habitable worlds. 409 00:15:58,640 --> 00:15:59,640 Yeah. 410 00:15:59,680 --> 00:16:01,800 But our journey through the Milky Way isn't over yet. 411 00:16:01,840 --> 00:16:02,840 No, it's not. 412 00:16:02,840 --> 00:16:04,400 Welcome back to Cosmos in a Pod. 413 00:16:04,440 --> 00:16:05,440 We're back. 414 00:16:05,480 --> 00:16:08,320 It's time for the grand finale of our journey across the Milky Way. 415 00:16:08,360 --> 00:16:09,960 The grand finale. 416 00:16:10,000 --> 00:16:13,360 We've explored alien planets, navigated star clusters, 417 00:16:13,400 --> 00:16:17,240 and now we're heading straight to the most extreme environment in our galaxy. 418 00:16:17,280 --> 00:16:19,080 That's right. The Galactic Center. 419 00:16:19,120 --> 00:16:21,960 A realm ruled by a supermassive black hole. 420 00:16:22,000 --> 00:16:24,840 Before we get too close to that cosmic monster, 421 00:16:24,880 --> 00:16:27,840 let's talk about what makes Sagittarius A so special. 422 00:16:27,880 --> 00:16:31,080 Okay. Sagittarius A, or S-G-R-A for short, 423 00:16:31,080 --> 00:16:32,840 is a supermassive black hole 424 00:16:32,880 --> 00:16:35,600 that's lurking at the very heart of the Milky Way. 425 00:16:35,640 --> 00:16:39,600 Imagine an object with a mass millions of times greater than our sun. 426 00:16:39,640 --> 00:16:40,640 Millions of times. 427 00:16:40,680 --> 00:16:43,360 Squeezed into a space smaller than our solar system. 428 00:16:43,400 --> 00:16:45,600 Millions of times the mass of our sun. 429 00:16:45,640 --> 00:16:46,640 That's mind-boggling. 430 00:16:46,680 --> 00:16:47,680 Yeah. 431 00:16:47,720 --> 00:16:49,680 How could something so massive be so incredibly compact? 432 00:16:49,720 --> 00:16:52,120 Well, it's one of the most bizarre consequences 433 00:16:52,160 --> 00:16:54,920 of Einstein's theory of general relativity. 434 00:16:54,960 --> 00:16:57,720 When a massive star collapses at the end of its life, 435 00:16:57,760 --> 00:16:59,360 its core can implode. 436 00:16:59,400 --> 00:17:00,400 Oh, wow. 437 00:17:00,400 --> 00:17:03,880 It's turning itself into an infinitesimally small point. 438 00:17:03,920 --> 00:17:06,440 And the gravitational pull becomes so intense 439 00:17:06,480 --> 00:17:09,240 that nothing, not even light, can escape its grasp. 440 00:17:09,280 --> 00:17:12,720 So how do we even know S-G-R-A is there if we can't see it directly? 441 00:17:12,760 --> 00:17:15,280 For decades, astronomers suspected its presence 442 00:17:15,320 --> 00:17:19,120 based on the strange movements of stars in the Galactic Center. 443 00:17:19,160 --> 00:17:21,400 These stars were whipping around an invisible point 444 00:17:21,440 --> 00:17:25,160 at incredible speeds as if being tugged by an unseen force. 445 00:17:25,200 --> 00:17:29,200 And then a few years ago, we got that incredible image of S-G-R-A's shadow 446 00:17:29,200 --> 00:17:31,400 confirming what astronomers had long suspected. 447 00:17:31,440 --> 00:17:32,440 Exactly. 448 00:17:32,480 --> 00:17:34,080 The Event Horizon Telescope, 449 00:17:34,120 --> 00:17:36,240 a network of radio telescopes around the world, 450 00:17:36,280 --> 00:17:39,280 captured that first-ever image of a black hole shadow. 451 00:17:39,320 --> 00:17:40,320 It was amazing. 452 00:17:40,360 --> 00:17:43,040 It was a blurry orange donut shape, 453 00:17:43,080 --> 00:17:45,280 but it represented a monumental achievement 454 00:17:45,320 --> 00:17:47,680 in our understanding of these enigmatic objects. 455 00:17:47,720 --> 00:17:49,600 So what's it like near a supermassive black hole? 456 00:17:49,640 --> 00:17:52,280 Is it just darkness and silence, or is there more to it? 457 00:17:52,320 --> 00:17:54,760 Oh, it's far from a quiet void. 458 00:17:54,800 --> 00:17:58,360 The region around S-G-R-A is a maelstrom of activity. 459 00:17:58,360 --> 00:17:59,360 Really? 460 00:17:59,400 --> 00:18:03,280 Stars gas and dust are swirling around the black hole at breakneck speeds. 461 00:18:03,320 --> 00:18:06,520 Some stars, like S-62, orbit so close 462 00:18:06,560 --> 00:18:09,120 that they reach a significant fraction of the speed of light. 463 00:18:09,160 --> 00:18:11,840 I can't even imagine what it would be like to witness that firsthand. 464 00:18:11,880 --> 00:18:13,720 I know. It's hard to comprehend. 465 00:18:13,760 --> 00:18:16,320 The sheer power and energy must be overwhelming. 466 00:18:16,360 --> 00:18:17,560 So it's not just about destruction. 467 00:18:17,600 --> 00:18:20,800 There's also a creative force at play in the Galactic Center. 468 00:18:20,840 --> 00:18:21,840 That's right. 469 00:18:21,880 --> 00:18:25,320 Black holes, despite their reputation as cosmic vacuum cleaners, 470 00:18:25,320 --> 00:18:29,120 might actually play a crucial role in the evolution of galaxies. 471 00:18:29,160 --> 00:18:30,160 How so? 472 00:18:30,200 --> 00:18:31,680 They can trigger star formation 473 00:18:31,720 --> 00:18:34,280 and regulate the growth of galactic structures. 474 00:18:34,320 --> 00:18:36,440 It's fascinating to think about the interconnectedness 475 00:18:36,480 --> 00:18:38,240 of all these cosmic phenomena. 476 00:18:38,280 --> 00:18:41,240 From the birth of stars in stellar nurseries 477 00:18:41,280 --> 00:18:45,000 to the death throes of massive stars collapsing into black holes. 478 00:18:45,040 --> 00:18:46,040 Yeah. 479 00:18:46,080 --> 00:18:47,600 It's a constant dance of energy and matter. 480 00:18:47,640 --> 00:18:50,800 It really is a beautiful and awe-inspiring dance. 481 00:18:50,840 --> 00:18:52,680 And our journey through the Milky Way 482 00:18:52,680 --> 00:18:56,640 has given us a glimpse into this grand cosmic dance. 483 00:18:56,680 --> 00:18:59,320 From the familiar stars in our night sky 484 00:18:59,360 --> 00:19:02,200 to the most extreme objects in the universe. 485 00:19:02,240 --> 00:19:03,240 Absolutely. 486 00:19:03,280 --> 00:19:04,560 It's been an incredible journey 487 00:19:04,600 --> 00:19:07,520 exploring the vastness and diversity of our galactic home. 488 00:19:07,560 --> 00:19:10,760 We've encountered planets that defy imagination, 489 00:19:10,800 --> 00:19:13,280 witnessed the birth and death of stars, 490 00:19:13,320 --> 00:19:16,480 and ventured into the heart of a supermassive black hole. 491 00:19:16,520 --> 00:19:18,000 What a journey it's been. 492 00:19:18,040 --> 00:19:20,160 And as we conclude our cosmic adventure, 493 00:19:20,160 --> 00:19:22,720 we hope you've gained a newfound appreciation 494 00:19:22,760 --> 00:19:26,320 for the wonders and mysteries that lie hidden within our own galaxy. 495 00:19:26,360 --> 00:19:29,280 There's so much out there to explore and discover. 496 00:19:29,320 --> 00:19:31,960 If you've enjoyed our deep dive into the Milky Way, 497 00:19:32,000 --> 00:19:34,160 be sure to subscribe to Cosmos in a Pod 498 00:19:34,200 --> 00:19:37,160 and follow us on YouTube for more cosmic explorations. 499 00:19:37,200 --> 00:19:38,840 We'd love to have you join us. 500 00:19:38,880 --> 00:19:41,440 Until next time, keep looking up and keep wondering. 501 00:19:41,440 --> 00:19:50,440 The universe is full of secrets waiting to be discovered.