1 00:00:00,000 --> 00:00:04,560 If you ever thought about what makes a planet a planet, 2 00:00:04,560 --> 00:00:06,160 is it just how big it is? 3 00:00:06,160 --> 00:00:08,320 Or is there something more to it? 4 00:00:08,320 --> 00:00:09,160 Right. 5 00:00:09,160 --> 00:00:10,900 Well, today we're diving deep 6 00:00:10,900 --> 00:00:12,960 into this whole world of planets. 7 00:00:12,960 --> 00:00:14,880 We've got the familiar ones in our solar system, 8 00:00:14,880 --> 00:00:18,840 but then some really out there planets you wouldn't believe. 9 00:00:18,840 --> 00:00:20,840 Yeah, some really exotic ones out there. 10 00:00:20,840 --> 00:00:25,000 Welcome to Cosmos in a Pod, Space and Astronomy series. 11 00:00:25,000 --> 00:00:27,480 Get ready to go way beyond 12 00:00:27,480 --> 00:00:29,600 the simple definition of a planet. 13 00:00:29,600 --> 00:00:33,120 We're gonna explore how astronomers actually classify 14 00:00:33,120 --> 00:00:35,360 all these crazy different worlds out there. 15 00:00:35,360 --> 00:00:38,640 A question that's really puzzled astronomers, 16 00:00:38,640 --> 00:00:40,640 I mean, for centuries really. 17 00:00:40,640 --> 00:00:42,080 Let's start with our own solar system. 18 00:00:42,080 --> 00:00:42,920 Okay. 19 00:00:42,920 --> 00:00:45,020 Remember back in 2006, that whole Pluto thing? 20 00:00:45,020 --> 00:00:45,860 Yeah, yeah. 21 00:00:45,860 --> 00:00:47,960 That really stirred things up, what happened there? 22 00:00:47,960 --> 00:00:52,040 So the International Astronomical Union, the IAU, 23 00:00:52,040 --> 00:00:54,780 they decided we need like a stricter definition 24 00:00:54,780 --> 00:00:57,280 for what is actually a planet. 25 00:00:57,280 --> 00:00:58,120 Okay. 26 00:00:58,120 --> 00:01:00,880 They came up with three key criteria. 27 00:01:00,880 --> 00:01:01,720 Right. 28 00:01:01,720 --> 00:01:03,280 First, it's gotta be orbiting the sun. 29 00:01:03,280 --> 00:01:04,120 Yeah. 30 00:01:04,120 --> 00:01:07,920 Second, it needs to be round, or at least nearly round, 31 00:01:07,920 --> 00:01:09,920 because of its own gravity. 32 00:01:09,920 --> 00:01:11,840 Basically, it has to be massive enough 33 00:01:11,840 --> 00:01:14,400 for gravity to pull it into a round shape. 34 00:01:14,400 --> 00:01:15,240 Okay. 35 00:01:15,240 --> 00:01:17,840 And third, and this is the tricky one, 36 00:01:17,840 --> 00:01:21,560 a planet has to have cleared its neighborhood. 37 00:01:21,560 --> 00:01:22,880 Cleared its neighborhood. 38 00:01:22,880 --> 00:01:24,480 What does that even mean? 39 00:01:24,480 --> 00:01:26,920 So it means that a planet has become 40 00:01:26,920 --> 00:01:31,200 the dominant gravitational force in its orbit, right? 41 00:01:31,200 --> 00:01:33,600 It's either swept up or flung away 42 00:01:33,600 --> 00:01:35,680 most of the other objects in its path. 43 00:01:35,680 --> 00:01:36,520 Oh, okay. 44 00:01:36,520 --> 00:01:38,840 And this is where Pluto fell short. 45 00:01:38,840 --> 00:01:39,680 Yeah. 46 00:01:39,680 --> 00:01:42,480 It shares its orbital space with a whole bunch 47 00:01:42,480 --> 00:01:45,120 of other icy bodies in the Kuiper belt. 48 00:01:45,120 --> 00:01:46,520 So Pluto got demoted, 49 00:01:46,520 --> 00:01:49,360 because it's not like a gravitational bully, so to speak. 50 00:01:49,360 --> 00:01:50,600 You could say that. 51 00:01:50,600 --> 00:01:52,840 I mean, it's more about gravitational dominance. 52 00:01:52,840 --> 00:01:55,320 And this definition, it works pretty well 53 00:01:55,320 --> 00:01:56,840 within our solar system. 54 00:01:56,840 --> 00:01:59,080 But when we start talking about exoplanets, 55 00:01:59,080 --> 00:02:01,040 planets outside of our solar system, 56 00:02:01,040 --> 00:02:02,640 things get a bit more complicated. 57 00:02:02,640 --> 00:02:03,800 I can imagine. 58 00:02:03,800 --> 00:02:06,320 Why is it harder to classify exoplanets? 59 00:02:06,320 --> 00:02:08,280 Well, it's really tough to observe 60 00:02:08,280 --> 00:02:11,480 those distant planetary systems in any detail. 61 00:02:11,480 --> 00:02:13,200 I can't always tell if a planet has 62 00:02:13,200 --> 00:02:14,600 cleared its neighborhood or not. 63 00:02:14,600 --> 00:02:15,480 That makes sense. 64 00:02:15,480 --> 00:02:18,840 So how do we even begin to classify 65 00:02:18,840 --> 00:02:21,000 those distant worlds then? 66 00:02:21,000 --> 00:02:23,960 Well, we rely on what we can observe, right? 67 00:02:23,960 --> 00:02:26,760 So their mass, their size, 68 00:02:26,760 --> 00:02:30,840 their composition, how far they are from their star, 69 00:02:30,840 --> 00:02:32,760 this gives us some clues about their structure 70 00:02:32,760 --> 00:02:33,920 and what they might be like. 71 00:02:33,920 --> 00:02:36,520 So let's break down these different types of planets 72 00:02:36,520 --> 00:02:37,360 that are out there. 73 00:02:37,360 --> 00:02:38,200 Oh, right. 74 00:02:38,200 --> 00:02:40,160 So we've got the familiar ones in our solar system. 75 00:02:40,160 --> 00:02:41,000 Right. 76 00:02:41,000 --> 00:02:43,240 You've got the rocky terrestrial planets, 77 00:02:43,240 --> 00:02:46,440 like Earth, Mars, Venus, Mercury. 78 00:02:46,440 --> 00:02:49,240 Right, and of course, Earth is the archetype here. 79 00:02:49,240 --> 00:02:53,240 It's the only one we know of so far that can support life. 80 00:02:53,240 --> 00:02:54,080 Right. 81 00:02:54,080 --> 00:02:56,200 And then you have the gas giants, Jupiter and Saturn. 82 00:02:56,200 --> 00:02:59,360 Massive planets composed mostly of hydrogen and helium. 83 00:02:59,360 --> 00:03:02,800 And then there's the ice giants, Uranus and Neptune, 84 00:03:02,800 --> 00:03:06,800 with their unique icy compositions. 85 00:03:06,800 --> 00:03:07,640 Exactly. 86 00:03:07,640 --> 00:03:09,440 Each type of these planets, 87 00:03:09,440 --> 00:03:12,840 they have their own special characteristics 88 00:03:12,840 --> 00:03:14,320 that help us classify them. 89 00:03:14,320 --> 00:03:16,920 But then things get really wild 90 00:03:16,920 --> 00:03:18,680 when we step outside of our solar system. 91 00:03:18,680 --> 00:03:19,520 Right. 92 00:03:19,520 --> 00:03:20,720 We start to find these planets, 93 00:03:20,720 --> 00:03:22,760 these types of planets that we don't even have here. 94 00:03:22,760 --> 00:03:24,960 Like tell me about these super Earths 95 00:03:24,960 --> 00:03:26,560 and mini Neptunes I've been hearing about. 96 00:03:26,560 --> 00:03:28,280 Ah, yes. 97 00:03:28,280 --> 00:03:32,040 Those are categories that are specific to exoplanets. 98 00:03:32,040 --> 00:03:34,640 Super Earths, as the name suggests, 99 00:03:34,640 --> 00:03:37,480 they're rocky planets, but they're bigger than Earth, 100 00:03:37,480 --> 00:03:39,440 but smaller than Neptune. 101 00:03:39,440 --> 00:03:41,000 And then mini Neptunes, 102 00:03:41,000 --> 00:03:43,960 they're like smaller versions of Neptune, 103 00:03:43,960 --> 00:03:45,960 but they have these thick atmospheres. 104 00:03:45,960 --> 00:03:46,800 You sound fascinating. 105 00:03:46,800 --> 00:03:48,880 Can you give me some specific examples of those? 106 00:03:48,880 --> 00:03:49,720 Sure, sure. 107 00:03:49,720 --> 00:03:52,840 There's Kepler 452b. 108 00:03:52,840 --> 00:03:53,680 Okay. 109 00:03:53,680 --> 00:03:54,760 It's a super Earth. 110 00:03:54,760 --> 00:03:58,600 It orbits a star, very similar to our sun, 111 00:03:58,600 --> 00:04:00,480 and it sits within the habitable zone. 112 00:04:00,480 --> 00:04:02,360 So that means it might have the right conditions 113 00:04:02,360 --> 00:04:05,680 for liquid water to exist on its surface. 114 00:04:05,680 --> 00:04:06,520 Wow. 115 00:04:06,520 --> 00:04:08,080 A potentially habitable super Earth. 116 00:04:08,080 --> 00:04:09,680 That's incredible. 117 00:04:09,680 --> 00:04:11,480 What about mini Neptunes? 118 00:04:11,480 --> 00:04:16,000 One really interesting one is TOI 270c. 119 00:04:16,000 --> 00:04:17,800 And studying this mini Neptune, 120 00:04:17,800 --> 00:04:20,000 it's helping us understand the transition 121 00:04:20,000 --> 00:04:22,880 between rocky planets and gas giants. 122 00:04:22,880 --> 00:04:25,400 So we're learning a lot about planet formation 123 00:04:25,400 --> 00:04:27,040 from these distant worlds. 124 00:04:27,040 --> 00:04:27,880 How eu-eu. 125 00:04:27,880 --> 00:04:29,960 And then there are rogue planets. 126 00:04:29,960 --> 00:04:30,800 Right. 127 00:04:30,800 --> 00:04:33,320 These are planets that aren't bound to any star. 128 00:04:33,320 --> 00:04:34,160 Right, yeah. 129 00:04:34,160 --> 00:04:35,680 And they just kind of drift through space. 130 00:04:35,680 --> 00:04:38,080 Yeah, they're just cruising through the galaxy 131 00:04:38,080 --> 00:04:39,080 all by themselves. 132 00:04:39,080 --> 00:04:40,120 Rogue planets. 133 00:04:40,120 --> 00:04:42,920 They sound like lonely wanderers of the cosmos. 134 00:04:42,920 --> 00:04:45,280 How do they even form? 135 00:04:45,280 --> 00:04:46,800 Well, they were probably ejected 136 00:04:46,800 --> 00:04:50,160 from their original solar systems when they were forming, 137 00:04:50,160 --> 00:04:51,800 maybe through gravitational interactions 138 00:04:51,800 --> 00:04:52,720 with other planets. 139 00:04:52,720 --> 00:04:57,480 One example is PSO J3 18.522. 140 00:04:57,480 --> 00:05:01,520 It's a rogue planet discovered back in 2013. 141 00:05:01,520 --> 00:05:03,240 It's amazing to even think about. 142 00:05:03,240 --> 00:05:05,760 So how common are these rogue planets? 143 00:05:05,760 --> 00:05:07,520 You know, it's hard to say for sure, 144 00:05:07,520 --> 00:05:10,000 but they might be more common than we think. 145 00:05:10,000 --> 00:05:10,840 Oh, yeah. 146 00:05:10,840 --> 00:05:12,680 They're just incredibly difficult to detect. 147 00:05:12,680 --> 00:05:13,520 Right. 148 00:05:13,520 --> 00:05:16,240 Because they don't emit much light. 149 00:05:16,240 --> 00:05:17,600 Okay, so we've covered the familiar, 150 00:05:17,600 --> 00:05:18,920 the somewhat familiar. 151 00:05:18,920 --> 00:05:19,760 Yeah. 152 00:05:19,760 --> 00:05:21,880 Now I'm ready for the truly weird stuff. 153 00:05:21,880 --> 00:05:23,640 Bring on the exotic planet types. 154 00:05:23,640 --> 00:05:26,040 What are like some of the strangest planets out there? 155 00:05:26,040 --> 00:05:28,880 Oh, get ready for some wild ones. 156 00:05:28,880 --> 00:05:30,840 So there are ocean worlds. 157 00:05:30,840 --> 00:05:31,680 Okay. 158 00:05:31,680 --> 00:05:34,440 These are planets completely covered in water. 159 00:05:34,440 --> 00:05:36,800 Think of a planet sized ocean. 160 00:05:36,800 --> 00:05:38,280 Whoa. 161 00:05:38,280 --> 00:05:40,480 Are there any real examples of those? 162 00:05:40,480 --> 00:05:42,440 Well, there's Europa. 163 00:05:42,440 --> 00:05:44,480 It's a moon of Jupiter. 164 00:05:44,480 --> 00:05:47,400 And it's thought to have a vast ocean 165 00:05:47,400 --> 00:05:48,920 beneath its icy surface. 166 00:05:48,920 --> 00:05:49,760 Okay. 167 00:05:49,760 --> 00:05:52,200 And then there's GJ 1214b. 168 00:05:52,200 --> 00:05:53,280 It's an exoplanet. 169 00:05:53,280 --> 00:05:56,480 And it shows strong evidence of being an ocean world. 170 00:05:56,480 --> 00:06:00,760 Imagine the possibilities for life in those environments. 171 00:06:00,760 --> 00:06:01,580 It's mind blowing. 172 00:06:01,580 --> 00:06:02,420 What else is out there? 173 00:06:02,420 --> 00:06:03,560 Then you've got lava worlds. 174 00:06:03,560 --> 00:06:04,400 Okay. 175 00:06:04,400 --> 00:06:05,440 Planets so close to their stars 176 00:06:05,440 --> 00:06:08,280 that their surfaces are just molten rock. 177 00:06:08,280 --> 00:06:11,120 55 Cancri E is a scorching example of this. 178 00:06:11,120 --> 00:06:12,720 This sounds incredibly harsh. 179 00:06:12,720 --> 00:06:15,280 How does scientists even study a place like that? 180 00:06:15,280 --> 00:06:16,200 It's a challenge. 181 00:06:16,200 --> 00:06:19,720 They have to rely on observing the planet's light 182 00:06:19,720 --> 00:06:21,960 and how it interacts with its atmosphere 183 00:06:21,960 --> 00:06:24,760 to try to learn about its composition and temperature. 184 00:06:24,760 --> 00:06:28,320 It's like trying to study a volcano up close. 185 00:06:28,320 --> 00:06:29,920 Wow, that's intense. 186 00:06:29,920 --> 00:06:31,600 What other bizarre planets are on the menu? 187 00:06:31,600 --> 00:06:34,920 Well, there's the hypothetical carbon planet. 188 00:06:34,920 --> 00:06:35,760 Okay. 189 00:06:35,760 --> 00:06:37,760 It's a world that's rich in carbon. 190 00:06:37,760 --> 00:06:40,160 Some scientists think that these planets, 191 00:06:40,160 --> 00:06:43,480 they could have surfaces made of graphite or even diamonds. 192 00:06:43,480 --> 00:06:44,480 A diamond planet. 193 00:06:44,480 --> 00:06:45,640 Now that's something I'd like to see. 194 00:06:45,640 --> 00:06:46,480 Yeah. 195 00:06:46,480 --> 00:06:47,600 Have we actually observed one yet? 196 00:06:47,600 --> 00:06:49,280 We haven't observed one yet. 197 00:06:49,280 --> 00:06:53,320 The theory is that they could form in star systems 198 00:06:53,320 --> 00:06:57,200 that have a higher carbon to oxygen ratio than our own. 199 00:06:57,200 --> 00:07:00,160 Okay, so maybe there's a whole blinged out solar system 200 00:07:00,160 --> 00:07:01,400 out there somewhere. 201 00:07:01,400 --> 00:07:02,240 What else we got? 202 00:07:02,240 --> 00:07:04,040 How about puffy planets? 203 00:07:04,040 --> 00:07:07,760 These are gas giants that are incredibly inflated 204 00:07:07,760 --> 00:07:09,600 because of the heat from their star. 205 00:07:09,600 --> 00:07:12,880 HATP67B is a good example. 206 00:07:12,880 --> 00:07:15,480 Puffy planets, lava worlds, diamond planets. 207 00:07:15,480 --> 00:07:18,320 This is wilder than any science fiction movie 208 00:07:18,320 --> 00:07:19,160 you've ever seen. 209 00:07:19,160 --> 00:07:20,000 I know, right? 210 00:07:20,000 --> 00:07:22,280 It's mind blowing. 211 00:07:22,280 --> 00:07:24,080 And then we have tidally locked planets. 212 00:07:24,080 --> 00:07:27,680 So this is where one side permanently faces the star 213 00:07:27,680 --> 00:07:30,120 and it results in these extreme temperature differences. 214 00:07:30,120 --> 00:07:34,000 So eternal day on one side, eternal night on the other. 215 00:07:34,000 --> 00:07:37,320 What would it even be like to live on a planet like that? 216 00:07:37,320 --> 00:07:38,240 Oh, it would definitely make 217 00:07:38,240 --> 00:07:40,880 for some unusual weather patterns. 218 00:07:40,880 --> 00:07:45,000 Trappist-1M is a tidally locked planet 219 00:07:45,000 --> 00:07:47,440 and it falls within the habitable zone of its star. 220 00:07:47,440 --> 00:07:51,840 So it's a really intriguing target for study. 221 00:07:51,840 --> 00:07:55,480 All these incredible discoveries must keep astronomers busy. 222 00:07:55,480 --> 00:07:58,880 So how do they even find and classify all these exoplanets 223 00:07:58,880 --> 00:07:59,800 in the first place? 224 00:07:59,800 --> 00:08:01,440 There are three main methods. 225 00:08:01,440 --> 00:08:02,880 There's the transit method. 226 00:08:02,880 --> 00:08:06,320 There's radial velocity and direct imaging. 227 00:08:06,320 --> 00:08:09,320 The transit method is the most commonly used one. 228 00:08:09,320 --> 00:08:12,920 It involves looking for these tiny dips 229 00:08:12,920 --> 00:08:16,040 in a star's brightness as a planet passes in front of it. 230 00:08:16,040 --> 00:08:17,640 Kind of like a mini eclipse. 231 00:08:17,640 --> 00:08:18,880 That sounds pretty ingenious. 232 00:08:18,880 --> 00:08:20,480 What about radial velocity? 233 00:08:20,480 --> 00:08:23,960 So radial velocity, that measures the wobble of a star 234 00:08:23,960 --> 00:08:27,280 caused by the gravitational pull of an orbiting planet. 235 00:08:27,280 --> 00:08:29,320 Ah, so we can detect planets 236 00:08:29,320 --> 00:08:31,200 even if we can't see them directly. 237 00:08:31,200 --> 00:08:32,200 Exactly, yeah. 238 00:08:32,200 --> 00:08:33,440 And then there's direct imaging. 239 00:08:33,440 --> 00:08:36,960 And that's literally taking a picture of a planet. 240 00:08:36,960 --> 00:08:37,800 Wow. 241 00:08:37,800 --> 00:08:38,960 But it's incredibly difficult. 242 00:08:38,960 --> 00:08:39,800 Yeah, I bet. 243 00:08:39,800 --> 00:08:42,720 Because planets are, they're so much fainter 244 00:08:42,720 --> 00:08:44,280 than their stars. 245 00:08:44,280 --> 00:08:46,280 Yeah, I can imagine that's quite a challenge. 246 00:08:46,280 --> 00:08:47,120 Yeah. 247 00:08:47,120 --> 00:08:50,200 What are we hoping to learn from 248 00:08:50,200 --> 00:08:51,920 directly imaging exoplanet? 249 00:08:51,920 --> 00:08:54,800 Oh, direct imaging, it can give us information 250 00:08:54,800 --> 00:08:57,920 about a planet's atmosphere, its temperature, 251 00:08:57,920 --> 00:09:00,880 and it might even allow us to search for signs of life. 252 00:09:00,880 --> 00:09:02,640 This is all so fascinating. 253 00:09:02,640 --> 00:09:05,480 But with so many new discoveries, 254 00:09:05,480 --> 00:09:07,680 there have to be some areas where our understanding 255 00:09:07,680 --> 00:09:09,200 is still evolving, right? 256 00:09:09,200 --> 00:09:10,160 Oh, absolutely. 257 00:09:10,160 --> 00:09:12,240 One of the biggest ongoing debates 258 00:09:12,240 --> 00:09:15,520 is where we draw the line between planets and dwarf planets. 259 00:09:15,520 --> 00:09:16,360 Right. 260 00:09:16,360 --> 00:09:20,280 There are objects out there that blur the lines, you know? 261 00:09:20,280 --> 00:09:22,440 And it makes classification tricky. 262 00:09:22,440 --> 00:09:24,320 I guess the more we discover, 263 00:09:24,320 --> 00:09:27,240 the more we realize how much we still don't know. 264 00:09:27,240 --> 00:09:29,920 Exactly, and that's what makes this field so exciting. 265 00:09:29,920 --> 00:09:32,440 You know, there are still so many unanswered questions 266 00:09:32,440 --> 00:09:36,280 about the universe's incredible array of planets. 267 00:09:36,280 --> 00:09:37,560 We've covered a lot of ground here. 268 00:09:37,560 --> 00:09:39,400 I'm definitely ready for a little break 269 00:09:39,400 --> 00:09:41,080 to let all this new information sink in. 270 00:09:41,080 --> 00:09:42,840 Me too. 271 00:09:42,840 --> 00:09:44,760 But stick with us because when we come back, 272 00:09:44,760 --> 00:09:47,960 we'll be diving even deeper into the mysteries 273 00:09:47,960 --> 00:09:51,360 of exoplanets and the search for life beyond Earth. 274 00:09:51,360 --> 00:09:53,600 And don't forget to follow Cosmos in a Pod 275 00:09:53,600 --> 00:09:55,400 and subscribe to our YouTube channel 276 00:09:55,400 --> 00:09:56,720 for more exciting deep dives 277 00:09:56,720 --> 00:09:59,120 into the mysteries of the universe. 278 00:09:59,120 --> 00:10:02,120 We'll be back soon with more fascinating insights. 279 00:10:02,120 --> 00:10:04,160 Welcome back to Cosmos in a Pod. 280 00:10:04,160 --> 00:10:06,520 So we've been talking about all these different, you know, 281 00:10:06,520 --> 00:10:08,840 types of planets, but I'm kind of curious, 282 00:10:08,840 --> 00:10:11,680 are these classifications always so clear cut? 283 00:10:11,680 --> 00:10:13,720 Are there like any cosmic objects 284 00:10:13,720 --> 00:10:17,080 that just don't fit neatly into those categories? 285 00:10:17,080 --> 00:10:18,920 Yeah, that's a great question. 286 00:10:18,920 --> 00:10:21,440 And it really shows how like our understanding 287 00:10:21,440 --> 00:10:23,280 of the universe is always changing, right? 288 00:10:23,280 --> 00:10:24,120 Right. 289 00:10:24,120 --> 00:10:25,760 Take brown dwarfs, for example. 290 00:10:25,760 --> 00:10:28,360 They're fascinating, they kind of blur the line 291 00:10:28,360 --> 00:10:30,840 between planets and stars. 292 00:10:30,840 --> 00:10:32,960 Brown dwarfs, I've heard that term before, 293 00:10:32,960 --> 00:10:34,320 but I'm not really sure what they are. 294 00:10:34,320 --> 00:10:36,680 You can think of them as like failed stars. 295 00:10:36,680 --> 00:10:37,520 Okay. 296 00:10:37,520 --> 00:10:39,600 They're bigger than giant planets, 297 00:10:39,600 --> 00:10:43,320 but they're not quite massive enough 298 00:10:43,320 --> 00:10:47,160 to sustain nuclear fusion in their cores, 299 00:10:47,160 --> 00:10:49,840 which is what powers, you know, stars. 300 00:10:49,840 --> 00:10:52,000 They're kind of stuck in this awkward in-between phase. 301 00:10:52,000 --> 00:10:55,600 Exactly, they're in this cosmic middle ground 302 00:10:55,600 --> 00:10:58,560 and their classification, oh, it's been debated for years. 303 00:10:58,560 --> 00:11:01,600 I can see how that would be a headache for astronomers. 304 00:11:01,600 --> 00:11:03,880 What makes them so hard to categorize? 305 00:11:03,880 --> 00:11:06,720 Well, their size and mass are big factors. 306 00:11:06,720 --> 00:11:09,080 I mean, they can be as small as some giant planets, 307 00:11:09,080 --> 00:11:11,080 but they can also be, you know, much bigger. 308 00:11:11,080 --> 00:11:13,320 And their composition can vary a lot too. 309 00:11:13,320 --> 00:11:16,640 So how do we tell if we're looking at a brown dwarf 310 00:11:16,640 --> 00:11:18,400 or just a really big planet? 311 00:11:18,400 --> 00:11:19,480 It's not always easy. 312 00:11:19,480 --> 00:11:22,840 Astronomers have to look at things like their temperature, 313 00:11:22,840 --> 00:11:25,880 their luminosity, and whether they show any signs 314 00:11:25,880 --> 00:11:29,560 of nuclear fusion, even if it's just, you know, a tiny bit. 315 00:11:29,560 --> 00:11:31,960 It sounds like a real cosmic detective story, 316 00:11:31,960 --> 00:11:33,360 trying to figure these things out. 317 00:11:33,360 --> 00:11:34,240 Oh, it really is. 318 00:11:34,240 --> 00:11:38,200 And it reminds us that the universe is full of surprises, 319 00:11:38,200 --> 00:11:41,360 and our understanding of it is always being refined 320 00:11:41,360 --> 00:11:43,720 as we make new discoveries. 321 00:11:43,720 --> 00:11:46,080 Speaking of refining our understanding, 322 00:11:46,080 --> 00:11:47,400 I've been thinking about that, 323 00:11:47,400 --> 00:11:51,280 that clearing its neighborhood criterion for planets. 324 00:11:51,280 --> 00:11:52,120 Right. 325 00:11:52,120 --> 00:11:54,400 It seems like that rule could be kind of subjective, 326 00:11:54,400 --> 00:11:56,760 especially when we're talking about exoplanets 327 00:11:56,760 --> 00:11:59,440 that, you know, we can't observe as clearly. 328 00:11:59,440 --> 00:12:01,160 Yeah, that's a really good point. 329 00:12:01,160 --> 00:12:03,440 And you're right, it's a point of a lot of debate 330 00:12:03,440 --> 00:12:04,720 among planetary scientists. 331 00:12:04,720 --> 00:12:06,480 There's actually a growing movement 332 00:12:06,480 --> 00:12:08,560 to reconsider that criterion, 333 00:12:08,560 --> 00:12:10,920 or maybe even, you know, get rid of it completely. 334 00:12:10,920 --> 00:12:12,520 Really, why is that? 335 00:12:12,520 --> 00:12:14,240 What are the arguments against it? 336 00:12:14,240 --> 00:12:15,320 Well, for one thing, 337 00:12:15,320 --> 00:12:17,640 it's just really hard to apply consistently. 338 00:12:17,640 --> 00:12:18,640 As we talked about earlier, 339 00:12:18,640 --> 00:12:23,640 it's much harder to observe distant exoplanetary systems 340 00:12:24,000 --> 00:12:28,960 and know for sure if a planet has truly cleared its orbit. 341 00:12:28,960 --> 00:12:31,840 So it's kind of biased towards planets in our solar system 342 00:12:31,840 --> 00:12:33,560 that we can see better. 343 00:12:33,560 --> 00:12:36,480 Yeah, some scientists argue that that's the case. 344 00:12:36,480 --> 00:12:40,280 They think a planet should be defined by its own properties, 345 00:12:40,280 --> 00:12:43,400 like its mass, its size, its composition, 346 00:12:43,400 --> 00:12:46,120 and, you know, not by what's going on around it 347 00:12:46,120 --> 00:12:46,960 in its orbit. 348 00:12:46,960 --> 00:12:47,840 That makes sense to me. 349 00:12:47,840 --> 00:12:48,960 I mean, a planet's a planet 350 00:12:48,960 --> 00:12:50,280 regardless of its neighbors, right? 351 00:12:50,280 --> 00:12:52,920 Exactly, and focusing on those intrinsic properties 352 00:12:52,920 --> 00:12:55,360 might actually allow us to classify more objects 353 00:12:55,360 --> 00:12:58,600 as planets, including some that are currently considered, 354 00:12:58,600 --> 00:13:00,040 you know, dwarf planets. 355 00:13:00,040 --> 00:13:02,600 So we're talking about a potential Pluto comeback, 356 00:13:02,600 --> 00:13:03,920 justice for Pluto. 357 00:13:03,920 --> 00:13:04,840 It's a possibility. 358 00:13:04,840 --> 00:13:06,480 The debate's still going on, 359 00:13:06,480 --> 00:13:09,280 and there's no clear consensus yet, 360 00:13:09,280 --> 00:13:11,400 but it's a really cool example 361 00:13:11,400 --> 00:13:15,120 of how our understanding of planets is constantly evolving. 362 00:13:15,120 --> 00:13:16,760 This whole planet classification thing 363 00:13:16,760 --> 00:13:19,400 is way more complex than I ever realized. 364 00:13:19,400 --> 00:13:20,240 It really is. 365 00:13:20,240 --> 00:13:23,720 It's like a reflection of the incredible diversity 366 00:13:23,720 --> 00:13:25,920 of the universe itself. 367 00:13:25,920 --> 00:13:28,040 There are so many different kinds of worlds out there, 368 00:13:28,040 --> 00:13:31,040 and we're really just starting to scratch the surface. 369 00:13:31,040 --> 00:13:33,280 Yeah, it makes you wonder what other strange 370 00:13:33,280 --> 00:13:36,360 and wonderful planets are out there 371 00:13:36,360 --> 00:13:38,680 just waiting to be discovered. 372 00:13:38,680 --> 00:13:41,600 What new technologies are astronomers using 373 00:13:41,600 --> 00:13:44,480 to kind of push the boundaries of our understanding? 374 00:13:44,480 --> 00:13:46,360 Well, the James Webb Space Telescape, 375 00:13:46,360 --> 00:13:48,440 it's been making some incredible discoveries 376 00:13:48,440 --> 00:13:49,280 since it launched. 377 00:13:49,280 --> 00:13:50,120 Right. 378 00:13:50,120 --> 00:13:51,680 Its instruments are so powerful. 379 00:13:51,680 --> 00:13:54,440 They let us study the atmospheres of exoplanets 380 00:13:54,440 --> 00:13:56,480 in more detail than ever before. 381 00:13:56,480 --> 00:13:57,320 That's right. 382 00:13:57,320 --> 00:14:00,040 I remember those stunning first images from Webb. 383 00:14:00,040 --> 00:14:00,880 Yeah. 384 00:14:00,880 --> 00:14:03,800 But how does studying those exoplanet atmospheres 385 00:14:03,800 --> 00:14:06,240 actually help us understand them better? 386 00:14:06,240 --> 00:14:09,560 You can think of it like taking a planet's fingerprint. 387 00:14:09,560 --> 00:14:10,400 Okay. 388 00:14:10,400 --> 00:14:12,000 The composition of an atmosphere 389 00:14:12,000 --> 00:14:14,600 can tell us a lot about a planet's history, 390 00:14:14,600 --> 00:14:17,800 how it formed, its potential for life, 391 00:14:17,800 --> 00:14:21,040 and maybe even whether it shows signs of life already. 392 00:14:21,040 --> 00:14:23,720 So we could potentially detect signs of life 393 00:14:23,720 --> 00:14:27,680 on other planets just by analyzing their atmospheres. 394 00:14:27,680 --> 00:14:28,640 That's the hope. 395 00:14:28,640 --> 00:14:30,920 We're looking for what we call biosignatures. 396 00:14:30,920 --> 00:14:33,600 So those are gases like oxygen or methane 397 00:14:33,600 --> 00:14:35,560 that could indicate there's some kind 398 00:14:35,560 --> 00:14:37,200 of biological activity going on. 399 00:14:37,200 --> 00:14:39,120 That would be groundbreaking. 400 00:14:39,120 --> 00:14:42,240 Are there any planets that are particularly promising 401 00:14:42,240 --> 00:14:43,680 for finding those biosignatures? 402 00:14:43,680 --> 00:14:45,160 Absolutely. 403 00:14:45,160 --> 00:14:47,240 The TRAPPIST-1 system is one 404 00:14:47,240 --> 00:14:49,640 that has a lot of scientists excited. 405 00:14:49,640 --> 00:14:50,480 Okay. 406 00:14:50,480 --> 00:14:52,400 It's a nearby star system 407 00:14:52,400 --> 00:14:55,880 with seven, count them, seven Earth-sized planets. 408 00:14:55,880 --> 00:14:56,720 Wow. 409 00:14:56,720 --> 00:14:58,640 And three of those are in the habitable zone. 410 00:14:58,640 --> 00:15:00,720 Seven Earth-sized planets. 411 00:15:00,720 --> 00:15:03,120 The possibilities are mind-boggling. 412 00:15:03,120 --> 00:15:05,160 What else is coming up in the world 413 00:15:05,160 --> 00:15:07,280 of exoplanet exploration? 414 00:15:07,280 --> 00:15:10,520 There's some really cool missions in the works, 415 00:15:10,520 --> 00:15:13,640 the European Space Agency's PLATO mission, for example. 416 00:15:13,640 --> 00:15:18,120 It's designed to find and study Earth-like planets 417 00:15:18,120 --> 00:15:19,880 around stars like our sun. 418 00:15:19,880 --> 00:15:21,560 So potentially finding more planets 419 00:15:21,560 --> 00:15:23,280 that could be like our own. 420 00:15:23,280 --> 00:15:24,120 Exactly. 421 00:15:24,120 --> 00:15:28,840 And then there's NASA's Nancy Grace Roman Space Telescope. 422 00:15:28,840 --> 00:15:30,640 That one's gonna have a wide field of view, 423 00:15:30,640 --> 00:15:32,920 which will let it search for exoplanets 424 00:15:32,920 --> 00:15:35,640 using a technique called microlensing. 425 00:15:35,640 --> 00:15:36,720 Microlensing. 426 00:15:36,720 --> 00:15:37,960 That sounds interesting. 427 00:15:37,960 --> 00:15:38,880 What is that exactly? 428 00:15:38,880 --> 00:15:40,640 It's a little complicated, 429 00:15:40,640 --> 00:15:43,400 but basically it uses the gravity of a star 430 00:15:43,400 --> 00:15:47,040 to magnify the light from a more distant star. 431 00:15:47,040 --> 00:15:47,880 Okay. 432 00:15:47,880 --> 00:15:51,000 And if there's a planet orbiting that closer star, 433 00:15:51,000 --> 00:15:53,360 it can cause a blip in that magnified light. 434 00:15:53,360 --> 00:15:56,680 So it's like using gravity as a cosmic magnifying glass. 435 00:15:56,680 --> 00:15:57,520 Precisely. 436 00:15:57,520 --> 00:15:59,400 It's a really powerful technique 437 00:15:59,400 --> 00:16:02,560 for finding planets that are further from their stars 438 00:16:02,560 --> 00:16:04,280 or planets that are just too small 439 00:16:04,280 --> 00:16:06,200 to detect using other methods. 440 00:16:06,200 --> 00:16:08,920 It sounds like the future of exoplanet discovery 441 00:16:08,920 --> 00:16:10,880 is incredibly bright. 442 00:16:10,880 --> 00:16:13,560 But before we get lost in all the excitement, 443 00:16:13,560 --> 00:16:15,680 I think it's time to kind of shift gears a bit. 444 00:16:15,680 --> 00:16:16,520 Okay. 445 00:16:16,520 --> 00:16:19,360 We've talked about the science of planet classification, 446 00:16:19,360 --> 00:16:22,240 the search for life, and the amazing technology 447 00:16:22,240 --> 00:16:24,320 that's helping us make those discoveries. 448 00:16:24,320 --> 00:16:28,040 But what about the ethical side of space exploration? 449 00:16:28,040 --> 00:16:30,040 It seems like there's some big questions 450 00:16:30,040 --> 00:16:32,600 we need to be asking as we venture 451 00:16:32,600 --> 00:16:34,080 further out into the cosmos. 452 00:16:34,080 --> 00:16:35,320 Yeah, you're absolutely right. 453 00:16:35,320 --> 00:16:36,680 As we explore the universe 454 00:16:36,680 --> 00:16:39,440 and potentially even encounter extraterrestrial life, 455 00:16:39,440 --> 00:16:43,080 we need to be thinking carefully about our responsibilities. 456 00:16:43,080 --> 00:16:46,160 It's a conversation we need to start having now 457 00:16:46,160 --> 00:16:48,880 before we actually face those challenges head on. 458 00:16:48,880 --> 00:16:49,960 Yeah. 459 00:16:49,960 --> 00:16:53,240 I'm definitely intrigued and maybe a little nervous 460 00:16:53,240 --> 00:16:56,840 to delve into those ethical considerations. 461 00:16:56,840 --> 00:16:58,280 It's understandable. 462 00:16:58,280 --> 00:17:01,000 We're talking about potentially encountering life 463 00:17:01,000 --> 00:17:01,840 as we don't know it. 464 00:17:01,840 --> 00:17:03,720 And that raises all sorts of questions 465 00:17:03,720 --> 00:17:06,200 about how we should interact, what our responsibilities are. 466 00:17:06,200 --> 00:17:08,480 This deep dive has taken us 467 00:17:08,480 --> 00:17:11,200 from the familiar planets in our solar system 468 00:17:11,200 --> 00:17:13,800 to the most bizarre worlds imaginable, 469 00:17:13,800 --> 00:17:17,680 and now to some really profound ethical questions. 470 00:17:17,680 --> 00:17:20,200 I can't wait to explore this next chapter. 471 00:17:20,200 --> 00:17:21,040 Me neither. 472 00:17:21,040 --> 00:17:23,280 Join us after the break as we contemplate 473 00:17:23,280 --> 00:17:26,840 the philosophical implications of our journey 474 00:17:26,840 --> 00:17:27,800 into the cosmos. 475 00:17:27,800 --> 00:17:29,920 And remember to follow Cosmos in a Pod 476 00:17:29,920 --> 00:17:31,520 and subscribe to our YouTube channel 477 00:17:31,520 --> 00:17:33,000 for more exciting deep dives 478 00:17:33,000 --> 00:17:34,840 into the mysteries of the universe. 479 00:17:35,920 --> 00:17:36,960 We'll be right back. 480 00:17:38,040 --> 00:17:40,120 Welcome back to Cosmos in a Pod. 481 00:17:40,120 --> 00:17:41,960 So we've been on this incredible journey, 482 00:17:41,960 --> 00:17:45,040 exploring all these different planets across the universe. 483 00:17:45,040 --> 00:17:47,520 But now let's think about something a bit deeper. 484 00:17:47,520 --> 00:17:49,160 Like the ethics of it all. 485 00:17:49,160 --> 00:17:52,240 The ethical side of space exploration. 486 00:17:52,240 --> 00:17:56,000 It's exciting and kind of daunting at the same time. 487 00:17:56,000 --> 00:17:59,560 It's definitely something we need to think about carefully. 488 00:17:59,560 --> 00:18:01,960 As we go further out there, 489 00:18:01,960 --> 00:18:03,920 the chances of us actually bumping 490 00:18:03,920 --> 00:18:07,000 into extraterrestrial life, well, they become more real. 491 00:18:07,000 --> 00:18:09,880 And that brings up a whole bunch of ethical dilemmas 492 00:18:09,880 --> 00:18:11,320 that we need to be ready for. 493 00:18:11,320 --> 00:18:13,240 Like what kind of challenges are we talking about? 494 00:18:13,240 --> 00:18:14,520 What are some examples? 495 00:18:14,520 --> 00:18:17,400 Well, one of the biggest worries is contamination. 496 00:18:17,400 --> 00:18:21,680 Like if we send probes or even people to other planets, 497 00:18:21,680 --> 00:18:22,760 there's a chance, right, 498 00:18:22,760 --> 00:18:25,960 that we could accidentally bring earth microbes with us. 499 00:18:25,960 --> 00:18:28,320 And those could be harmful to any life 500 00:18:28,320 --> 00:18:30,000 that might already be there. 501 00:18:30,000 --> 00:18:32,760 So we could accidentally wipe out alien life 502 00:18:32,760 --> 00:18:34,520 before we even know it exists. 503 00:18:34,520 --> 00:18:39,520 It would be a huge loss, scientifically and ethically. 504 00:18:40,520 --> 00:18:42,440 And then there's also the flip side. 505 00:18:42,440 --> 00:18:44,760 We gotta think about those extraterrestrial organisms 506 00:18:44,760 --> 00:18:47,080 potentially contaminating earth. 507 00:18:47,080 --> 00:18:52,080 We don't know how our biosphere would react to alien life. 508 00:18:52,400 --> 00:18:54,640 It sounds like something straight out of a sci-fi movie. 509 00:18:54,640 --> 00:18:55,560 I know, right. 510 00:18:55,560 --> 00:18:58,040 But it's a real possibility we need to consider. 511 00:18:58,040 --> 00:19:02,160 What are scientists doing to try and minimize those risks? 512 00:19:02,160 --> 00:19:04,400 Well, planetary protection protocols. 513 00:19:04,400 --> 00:19:07,680 Those are like a super important part of any space mission. 514 00:19:07,680 --> 00:19:09,520 Probes in spacecraft, they go through 515 00:19:09,520 --> 00:19:12,000 this intense sterilization process 516 00:19:12,000 --> 00:19:14,280 to reduce the risk of contamination. 517 00:19:14,280 --> 00:19:16,640 So it's like washing your hands before dinner, 518 00:19:16,640 --> 00:19:18,600 but on a cosmic scale. 519 00:19:18,600 --> 00:19:19,440 Exactly. 520 00:19:19,440 --> 00:19:23,400 And there are very strict rules for handling any samples 521 00:19:23,400 --> 00:19:24,920 that come back from other planets. 522 00:19:24,920 --> 00:19:27,680 Like the Mars sample return mission, for example. 523 00:19:27,680 --> 00:19:28,520 Yeah, makes sense. 524 00:19:28,520 --> 00:19:31,400 Better safe than sorry, especially when we're dealing with 525 00:19:31,400 --> 00:19:33,680 things we don't even understand. 526 00:19:33,680 --> 00:19:36,120 But what about if we actually do find 527 00:19:36,120 --> 00:19:37,600 intelligent alien life? 528 00:19:37,600 --> 00:19:40,480 Like how do we even begin to talk to them 529 00:19:40,480 --> 00:19:41,600 to interact with them? 530 00:19:41,600 --> 00:19:44,000 Oh, that's where things get really tricky. 531 00:19:44,000 --> 00:19:46,720 There are a lot of discussions happening right now 532 00:19:46,720 --> 00:19:48,920 about how to create a universal language 533 00:19:48,920 --> 00:19:51,280 or some kind of protocol for communicating 534 00:19:51,280 --> 00:19:53,880 with extraterrestrial intelligence. 535 00:19:53,880 --> 00:19:55,960 I mean, it's hard enough to communicate with people 536 00:19:55,960 --> 00:19:58,120 from different cultures here on Earth. 537 00:19:58,120 --> 00:20:02,760 Imagine trying to bridge that gap with beings 538 00:20:02,760 --> 00:20:04,440 from a whole other planet. 539 00:20:04,440 --> 00:20:05,680 It would be an immense challenge. 540 00:20:05,680 --> 00:20:09,680 We'd have to completely rethink how we understand language, 541 00:20:09,680 --> 00:20:10,680 how we communicate. 542 00:20:10,680 --> 00:20:12,560 And then there are the questions of rights 543 00:20:12,560 --> 00:20:13,760 and responsibilities. 544 00:20:13,760 --> 00:20:17,200 Do extraterrestrial beings have the same rights as humans? 545 00:20:17,200 --> 00:20:19,480 How do we make sure they're safe? 546 00:20:19,480 --> 00:20:21,320 What if their values, what if their goals 547 00:20:21,320 --> 00:20:22,760 are totally different from ours? 548 00:20:22,760 --> 00:20:25,720 It's like a whole new frontier, not just in science, 549 00:20:25,720 --> 00:20:28,480 but in ethics and philosophy too. 550 00:20:28,480 --> 00:20:32,080 Absolutely, it's crucial to have these conversations now 551 00:20:32,080 --> 00:20:35,080 before we're actually in these situations. 552 00:20:35,080 --> 00:20:38,240 We need to approach space exploration with responsibility 553 00:20:38,240 --> 00:20:39,560 and respect for the universe 554 00:20:39,560 --> 00:20:42,080 and everything that might be out there. 555 00:20:42,080 --> 00:20:43,000 I couldn't agree more. 556 00:20:43,000 --> 00:20:45,000 This deep dive has really changed 557 00:20:45,000 --> 00:20:47,800 how I see exploring the cosmos. 558 00:20:47,800 --> 00:20:49,800 It's not just about scientific discoveries. 559 00:20:49,800 --> 00:20:53,040 It's about understanding our place in the universe 560 00:20:53,040 --> 00:20:57,720 and our responsibilities as citizens of the cosmos. 561 00:20:57,720 --> 00:20:58,560 Well said. 562 00:20:58,560 --> 00:21:01,240 It's a humbling and awe-inspiring endeavor. 563 00:21:01,240 --> 00:21:04,920 It really requires careful thought and consideration. 564 00:21:04,920 --> 00:21:06,360 It's been an amazing journey, 565 00:21:06,360 --> 00:21:09,320 going from those familiar planets in our own solar system 566 00:21:09,320 --> 00:21:11,480 to the most bizarre worlds we can imagine. 567 00:21:11,480 --> 00:21:13,840 And it's clear we've only just scratched the surface. 568 00:21:13,840 --> 00:21:15,280 The universe is full of wonders, 569 00:21:15,280 --> 00:21:17,520 just waiting for us to discover them. 570 00:21:17,520 --> 00:21:19,600 Who knows what incredible planets 571 00:21:19,600 --> 00:21:21,240 and life forms are out there? 572 00:21:21,240 --> 00:21:22,360 It's truly mind-blowing. 573 00:21:22,360 --> 00:21:24,200 Well, that's all the time we have for today's deep dive 574 00:21:24,200 --> 00:21:26,960 into the world of planets, but that the exploration continues. 575 00:21:26,960 --> 00:21:28,960 Don't forget to follow Cosmos in a pod 576 00:21:28,960 --> 00:21:30,760 and subscribe to our YouTube channel 577 00:21:30,760 --> 00:21:32,200 for more exciting deep dives 578 00:21:32,200 --> 00:21:34,040 into the mysteries of the universe. 579 00:21:34,040 --> 00:21:35,640 Until next time, keep looking up 580 00:21:35,640 --> 00:21:41,640 and never stop exploring those wonders of the cosmos.