1 00:00:01,671 --> 00:00:04,105 NARRATOR: Across the solar system, 2 00:00:04,105 --> 00:00:08,438 spectacular storms are raging. 3 00:00:08,438 --> 00:00:10,971 JAMES DOTTIN: What we've learned about weather on other planets 4 00:00:10,971 --> 00:00:14,038 has rewritten the rulebook on what we thought was possible. 5 00:00:14,038 --> 00:00:17,338 NARRATOR: From corrosive clouds... 6 00:00:17,338 --> 00:00:20,771 GEORGE DRANSFIELD: If you were to go skydiving through the clouds of Venus, 7 00:00:20,771 --> 00:00:23,538 there wouldn't be a lot of you left at the end. 8 00:00:23,538 --> 00:00:26,271 NARRATOR: ...to global dust storms. 9 00:00:26,271 --> 00:00:29,871 DAVID GRINSPOON: On Mars, the whole atmosphere basically freaks out, 10 00:00:29,871 --> 00:00:33,138 and the storm grows to the point 11 00:00:33,138 --> 00:00:34,771 where it engulfs the entire planet. 12 00:00:34,771 --> 00:00:36,471 We don't have anything like that on Earth. 13 00:00:36,471 --> 00:00:40,405 NARRATOR: Storms found in unexpected places... 14 00:00:40,405 --> 00:00:44,138 DERRICK PITTS: It's a moon that looks like this! 15 00:00:44,138 --> 00:00:47,138 How do you have these features on the moon of a planet? 16 00:00:47,138 --> 00:00:51,905 NARRATOR: ...and made of bizarre materials. 17 00:00:51,905 --> 00:00:53,805 SHANNON MACKENZIE: Buckets and buckets of rain 18 00:00:53,805 --> 00:00:55,838 are falling on the surface, and yet, 19 00:00:55,838 --> 00:00:58,105 it's not water raining out of the atmosphere, 20 00:00:58,105 --> 00:00:59,138 but liquid methane. 21 00:00:59,138 --> 00:01:01,705 NARRATOR: Extra-terrestrial weather 22 00:01:01,705 --> 00:01:03,838 makes exploration challenging. 23 00:01:06,038 --> 00:01:08,605 ABIGAIL FRAEMAN: Seeing the skies get darker and darker and darker, 24 00:01:08,605 --> 00:01:10,038 we started to realize that, 25 00:01:10,038 --> 00:01:12,838 "Oh, this is actually, this is a really bad one." 26 00:01:12,838 --> 00:01:16,738 NARRATOR: But can teach us so much. 27 00:01:16,738 --> 00:01:20,205 PETER GAO: It opens up the possibilities of, "What is weather?" 28 00:01:22,571 --> 00:01:28,538 NARRATOR: What drives these exotic storms raging across the solar system? 29 00:01:28,538 --> 00:01:32,771 And how do they shape a planet's destiny? 30 00:01:32,771 --> 00:01:36,271 "Solar System: Storm Worlds." 31 00:01:36,271 --> 00:01:39,971 Right now, on "NOVA." 32 00:01:39,971 --> 00:01:46,238 ♪ ♪ 33 00:01:53,638 --> 00:01:57,871 ♪ ♪ 34 00:02:12,271 --> 00:02:14,371 NARRATOR: It's midsummer. 35 00:02:14,371 --> 00:02:20,738 ♪ ♪ 36 00:02:20,738 --> 00:02:23,538 A storm is brewing. 37 00:02:27,871 --> 00:02:32,638 ♪ ♪ 38 00:02:32,638 --> 00:02:36,038 It unleashes torrents of rain... 39 00:02:40,905 --> 00:02:45,671 ...forming floods that drain into rushing rivers... 40 00:02:45,671 --> 00:02:51,438 ♪ ♪ 41 00:02:51,438 --> 00:02:54,438 ...and giant lakes. 42 00:02:54,438 --> 00:02:58,205 ♪ ♪ 43 00:02:58,205 --> 00:03:03,138 This is the only world in our solar system 44 00:03:03,138 --> 00:03:07,138 where rainstorms pummel the surface. 45 00:03:07,138 --> 00:03:11,371 ♪ ♪ 46 00:03:11,371 --> 00:03:14,905 The only world other than Earth. 47 00:03:19,505 --> 00:03:24,138 Here, more than 800 million miles from the sun... 48 00:03:26,238 --> 00:03:29,638 ...orbits the largest of Saturn's moons. 49 00:03:33,371 --> 00:03:35,971 In some ways, Titan is more similar to Earth 50 00:03:35,971 --> 00:03:38,805 than any other place in the solar system. 51 00:03:38,805 --> 00:03:40,771 But upon closer inspection, 52 00:03:40,771 --> 00:03:43,238 you will find that it's actually exceptionally alien. 53 00:03:43,238 --> 00:03:46,438 The surface temperature of Titan 54 00:03:46,438 --> 00:03:49,738 is around -300 degrees Fahrenheit. 55 00:03:49,738 --> 00:03:53,305 NARRATOR: Far too cold for liquid water. 56 00:03:55,305 --> 00:03:57,105 DOTTIN: What's fascinating is that 57 00:03:57,105 --> 00:03:59,371 the rain that's falling out of the sky on Titan 58 00:03:59,371 --> 00:04:00,771 and filling up the lakes 59 00:04:00,771 --> 00:04:04,138 is usually found on Earth as a flammable gas. 60 00:04:07,805 --> 00:04:09,071 NARRATOR: Methane. 61 00:04:09,071 --> 00:04:12,938 Titan is a world shaped by alien storms, 62 00:04:12,938 --> 00:04:15,805 and it is not alone. 63 00:04:15,805 --> 00:04:17,571 MACKENZIE: It's pretty mind-blowing 64 00:04:17,571 --> 00:04:20,405 that as we look elsewhere in the solar system, 65 00:04:20,405 --> 00:04:21,838 we see these weather patterns 66 00:04:21,838 --> 00:04:25,371 that look very familiar to us, 67 00:04:25,371 --> 00:04:28,705 and yet there are also these wild extremes. 68 00:04:28,705 --> 00:04:30,805 ♪ ♪ 69 00:04:30,805 --> 00:04:32,371 DRANSFIELD: Some of the storms we're seeing 70 00:04:32,371 --> 00:04:33,871 are like supersized versions 71 00:04:33,871 --> 00:04:35,671 of the storms that we see here on Earth. 72 00:04:35,671 --> 00:04:37,805 ♪ ♪ 73 00:04:37,805 --> 00:04:40,771 NARRATOR: And the more we explore, 74 00:04:40,771 --> 00:04:43,738 the more weird and wonderful weather we're finding. 75 00:04:43,738 --> 00:04:46,438 GRINSPOON: Pretty much every planet with weather 76 00:04:46,438 --> 00:04:50,271 has some oddity to it that's surprised us. 77 00:04:51,738 --> 00:04:55,138 NARRATOR: So what creates the wild diversity in weather 78 00:04:55,138 --> 00:04:57,405 across the solar system? 79 00:04:58,738 --> 00:05:02,205 GAO: We're so used to dealing with our specific brand of weather. 80 00:05:02,205 --> 00:05:03,871 But there's just so much more out there, 81 00:05:03,871 --> 00:05:05,738 if you look at these stormy worlds. 82 00:05:05,738 --> 00:05:10,771 ♪ ♪ 83 00:05:25,605 --> 00:05:30,005 ♪ ♪ 84 00:05:30,005 --> 00:05:32,038 ALEJANDRO SOTO: When I hear the word "weather," 85 00:05:32,038 --> 00:05:35,705 I get a memory 86 00:05:35,705 --> 00:05:39,405 of when I was a kid, standing out in a field... 87 00:05:39,405 --> 00:05:41,671 ♪ ♪ 88 00:05:41,671 --> 00:05:44,538 ...when the wind would pick up, the sky would darken a bit, 89 00:05:44,538 --> 00:05:46,305 and you knew it was about to rain. 90 00:05:46,305 --> 00:05:49,438 (wind gusting) 91 00:05:49,438 --> 00:05:52,405 And yet it would also be the best. 92 00:05:54,738 --> 00:05:57,905 NARRATOR: From towering thunderstorms 93 00:05:57,905 --> 00:06:02,405 to howling blizzards 94 00:06:02,405 --> 00:06:07,705 to choking dust storms, 95 00:06:07,705 --> 00:06:11,271 our atmosphere is a restless place. 96 00:06:14,005 --> 00:06:18,805 But what causes all this chaos? 97 00:06:18,805 --> 00:06:21,138 JEN GUPTA: Earth, like all the planets, 98 00:06:21,138 --> 00:06:24,271 is essentially a big ball floating in space 99 00:06:24,271 --> 00:06:27,405 being heated by the sun. 100 00:06:27,405 --> 00:06:29,238 It's pretty simple, really. 101 00:06:29,238 --> 00:06:31,271 But because of the shape of a planet, 102 00:06:31,271 --> 00:06:34,571 its spherical geometry, 103 00:06:34,571 --> 00:06:37,171 it's actually really hard to heat the planet evenly. 104 00:06:37,171 --> 00:06:38,571 For a start, 105 00:06:38,571 --> 00:06:40,338 there's always a side of the Earth 106 00:06:40,338 --> 00:06:43,605   in darkness, the night side of the planet. 107 00:06:43,605 --> 00:06:44,705 DOTTIN: And some parts, 108 00:06:44,705 --> 00:06:46,105 like the Equator, 109 00:06:46,105 --> 00:06:47,871 receive more sunlight 110 00:06:47,871 --> 00:06:49,238 than others, like the poles, 111 00:06:49,238 --> 00:06:53,271 and that creates an energy imbalance. 112 00:06:53,271 --> 00:06:57,138 But because the Earth is surrounded by this atmosphere, 113 00:06:57,138 --> 00:07:00,371 this envelope of gas that's free to move around, 114 00:07:00,371 --> 00:07:04,071 it can carry the heat from the hot places to the cold 115 00:07:04,071 --> 00:07:07,471 in an attempt to equalize this imbalance. 116 00:07:07,471 --> 00:07:11,438 LEIGH FLETCHER: And without that conveyor belt of energy motion, 117 00:07:11,438 --> 00:07:13,138 we wouldn't have 118 00:07:13,138 --> 00:07:14,571 the incredible diversity of weather 119 00:07:14,571 --> 00:07:16,105 that we can see around us today. 120 00:07:16,105 --> 00:07:20,438 ♪ ♪ 121 00:07:20,438 --> 00:07:23,871 NARRATOR: Wind, rain, and lightning are all side effects 122 00:07:23,871 --> 00:07:27,771 as our atmosphere balances hot and cold. 123 00:07:27,771 --> 00:07:30,805 ♪ ♪ 124 00:07:30,805 --> 00:07:36,271 And what applies here applies elsewhere, too. 125 00:07:36,271 --> 00:07:38,805 CLARA SOUSA-SILVA: In our solar system, wherever there's an atmosphere, 126 00:07:38,805 --> 00:07:41,671 there's weather, no matter how different 127 00:07:41,671 --> 00:07:43,605 an atmosphere from Earth's. 128 00:07:43,605 --> 00:07:45,771   FRAEMAN: Some are thicker, some are thinner, 129 00:07:45,771 --> 00:07:48,438 sometimes they're made of different things. 130 00:07:48,438 --> 00:07:49,805 And all of these combine 131 00:07:49,805 --> 00:07:53,271 to give these crazy cool weather systems 132 00:07:53,271 --> 00:07:54,705 that are all so different 133 00:07:54,705 --> 00:07:56,105 across the solar system. 134 00:07:56,105 --> 00:08:00,238 ♪ ♪ 135 00:08:03,405 --> 00:08:06,038 NARRATOR: To see this alien weather in action 136 00:08:06,038 --> 00:08:09,871 across our vast solar system, 137 00:08:09,871 --> 00:08:12,971 we head away from our shared star... 138 00:08:12,971 --> 00:08:17,205 ♪ ♪ 139 00:08:17,205 --> 00:08:20,338 ...passing a planet so small and close to the sun 140 00:08:20,338 --> 00:08:24,271 that it has no atmosphere, 141 00:08:24,271 --> 00:08:27,505 to encounter a planet 142 00:08:27,505 --> 00:08:31,205 smothered by one. 143 00:08:37,805 --> 00:08:42,138 PITTS: Venus looks so beautiful in the evening sky. 144 00:08:42,138 --> 00:08:44,771 Brilliant, clear, white, 145 00:08:44,771 --> 00:08:47,671 just stunningly lovely to see, 146 00:08:47,671 --> 00:08:52,038 yet it's such a horribly nasty environment. 147 00:08:53,738 --> 00:08:55,905   NARRATOR: Looking down from orbit, 148 00:08:55,905 --> 00:09:01,171 we can't actually see Venus's surface at all. 149 00:09:03,138 --> 00:09:09,105 Instead, all we see are endless, thick, churning clouds 150 00:09:09,105 --> 00:09:12,805 that completely conceal the rest of the planet. 151 00:09:12,805 --> 00:09:16,805 ♪ ♪ 152 00:09:16,805 --> 00:09:19,805 GRINSPOON: Historically, we thought, "Oh, Venus has clouds. 153 00:09:19,805 --> 00:09:21,538 "They're probably made out of water. 154 00:09:21,538 --> 00:09:22,838 It might be sort of nice there." 155 00:09:22,838 --> 00:09:24,371 (laughing): But then, 156 00:09:24,371 --> 00:09:28,571 when we started to actually get data from spacecraft, 157 00:09:28,571 --> 00:09:30,571 we discovered, no, they're not water. 158 00:09:30,571 --> 00:09:31,771 In fact, they're battery acid. 159 00:09:31,771 --> 00:09:35,571 ♪ ♪ 160 00:09:35,571 --> 00:09:37,105 SOUSA-SILVA: The clouds on Venus are 161 00:09:37,105 --> 00:09:40,138 made up of extremely concentrated sulfuric acid, 162 00:09:40,138 --> 00:09:42,905 one of the most corrosive substances we know of. 163 00:09:42,905 --> 00:09:44,605 If you were to go skydiving 164 00:09:44,605 --> 00:09:46,271 through the clouds of Venus, 165 00:09:46,271 --> 00:09:48,938 there wouldn't be a lot of you left at the end. 166 00:09:52,371 --> 00:09:56,338 NARRATOR: But if we could withstand the acid 167 00:09:56,338 --> 00:09:59,671 and took the plunge down through Venus's clouds... 168 00:10:03,005 --> 00:10:06,771 ...we'd reach a landscape that is eerily calm... 169 00:10:08,805 --> 00:10:12,338 ...but with air pressure more than 90 times greater 170 00:10:12,338 --> 00:10:14,805 than at Earth's surface. 171 00:10:14,805 --> 00:10:16,538 GAO: Even though we don't realize it, 172 00:10:16,538 --> 00:10:17,871 air has weight. 173 00:10:17,871 --> 00:10:19,338 It's being pulled down by gravity, 174 00:10:19,338 --> 00:10:20,571 just like the rest of us. 175 00:10:20,571 --> 00:10:22,371 And so, on Venus, where the atmosphere 176 00:10:22,371 --> 00:10:24,438 is so thick and so massive, 177 00:10:24,438 --> 00:10:26,171 all that air is being pulled down, 178 00:10:26,171 --> 00:10:27,905 and if we're on the bottom of it, 179 00:10:27,905 --> 00:10:29,805 then we'll feel all that pressure. 180 00:10:29,805 --> 00:10:32,471 SOUSA-SILVA: If you find yourself on the surface of Venus, 181 00:10:32,471 --> 00:10:35,605 you would almost immediately be crushed. 182 00:10:35,605 --> 00:10:37,871 But if somehow you survived 183 00:10:37,871 --> 00:10:41,038 and tried to go for a stroll, it would be exhausting. 184 00:10:41,038 --> 00:10:42,738 The atmosphere is so thick, 185 00:10:42,738 --> 00:10:44,838 it would be like walking through molasses. 186 00:10:46,738 --> 00:10:48,605 NARRATOR: The surface of Venus 187 00:10:48,605 --> 00:10:51,605 is comparable to the bottom of Earth's oceans, 188 00:10:51,605 --> 00:10:54,105 but with a key difference. 189 00:10:55,605 --> 00:10:58,238 At about 900 degrees Fahrenheit, 190 00:10:58,238 --> 00:11:02,205 this is the hottest planetary surface in the solar system. 191 00:11:04,171 --> 00:11:08,805 And again, Venus's extreme atmosphere is responsible. 192 00:11:08,805 --> 00:11:11,271 SOUSA-SILVA: Carbon dioxide and other molecules 193 00:11:11,271 --> 00:11:13,471 are able to absorb and radiate heat, 194 00:11:13,471 --> 00:11:15,605 and so, in large enough quantities, 195 00:11:15,605 --> 00:11:17,271 they can act like a planetary blanket 196 00:11:17,271 --> 00:11:18,938 that traps that heat in a planet. 197 00:11:18,938 --> 00:11:21,805 That's what we call the greenhouse effect. 198 00:11:23,805 --> 00:11:26,371 NARRATOR: And Venus's incredibly dense atmosphere 199 00:11:26,371 --> 00:11:30,371 is 96.5% carbon dioxide. 200 00:11:30,371 --> 00:11:33,071 ♪ ♪ 201 00:11:33,071 --> 00:11:36,305 Even 0.04% CO2 in our atmosphere 202 00:11:36,305 --> 00:11:38,705 is enough to initiate a climate crisis 203 00:11:38,705 --> 00:11:40,805 in our world right now. 204 00:11:40,805 --> 00:11:43,238 So you can imagine how bad it is on Venus. 205 00:11:46,738 --> 00:11:49,171 NARRATOR: Venus's extreme greenhouse effect 206 00:11:49,171 --> 00:11:52,771 means it's even hotter than Mercury. 207 00:11:55,338 --> 00:11:57,505 Which is why what we would find there 208 00:11:57,505 --> 00:11:59,905 is so extraordinary. 209 00:11:59,905 --> 00:12:03,038 ♪ ♪ 210 00:12:03,038 --> 00:12:05,771 What look like snow-capped mountains 211 00:12:05,771 --> 00:12:09,871 towering over the scalding surface. 212 00:12:15,805 --> 00:12:18,638 For generations, we could only guess 213 00:12:18,638 --> 00:12:21,205 at what lay beneath Venus's clouds. 214 00:12:22,505 --> 00:12:25,638 But, thanks to radar images 215 00:12:25,638 --> 00:12:28,805 beamed back by NASA's Magellan orbiter, 216 00:12:28,805 --> 00:12:33,805 we now have detailed maps of the planet's surface. 217 00:12:33,805 --> 00:12:36,005 So, here we have an image taken by Magellan, 218 00:12:36,005 --> 00:12:37,038 and what we're looking at 219 00:12:37,038 --> 00:12:39,171 is actually Maxwell Montes. 220 00:12:39,171 --> 00:12:40,171 Maxwell Montes here 221 00:12:40,171 --> 00:12:42,705 is the highest region on Venus. 222 00:12:42,705 --> 00:12:46,705 And what you'll notice is that around this image, 223 00:12:46,705 --> 00:12:48,838 the surface looks dark. 224 00:12:48,838 --> 00:12:51,538 But in the center, where Maxwell Montes is, 225 00:12:51,538 --> 00:12:53,971 it's much brighter-- it almost looks white. 226 00:12:53,971 --> 00:12:55,671 We weren't expecting 227 00:12:55,671 --> 00:12:57,871 to have such radar-bright regions 228 00:12:57,871 --> 00:13:00,605 on the highlands, in the mountaintops of Venus. 229 00:13:00,605 --> 00:13:04,238 ♪ ♪ 230 00:13:04,238 --> 00:13:07,571 GUPTA: When you see those radar images of Maxwell Montes, 231 00:13:07,571 --> 00:13:10,771 it's hard not to imagine snow-capped mountains. 232 00:13:10,771 --> 00:13:14,038 ♪ ♪ 233 00:13:14,038 --> 00:13:16,738 NARRATOR: But given the conditions on Venus, 234 00:13:16,738 --> 00:13:20,805 snow as we know it is impossible. 235 00:13:20,805 --> 00:13:23,805 ♪ ♪ 236 00:13:23,805 --> 00:13:26,171 In places, it's so hot, 237 00:13:26,171 --> 00:13:28,871 the ground actually glows, 238 00:13:28,871 --> 00:13:32,805 like metal coming out of a forge. 239 00:13:32,805 --> 00:13:34,538 GRINSPOON: On Earth, you can imagine 240 00:13:34,538 --> 00:13:36,338 waiting till nighttime to cool off. 241 00:13:36,338 --> 00:13:37,871 That wouldn't work on Venus. 242 00:13:37,871 --> 00:13:40,805 There's no relief at night on Venus from the temperature. 243 00:13:40,805 --> 00:13:43,105 And in fact, if you go from the equator to the pole, 244 00:13:43,105 --> 00:13:46,071 it doesn't get any cooler, for the same reason-- 245 00:13:46,071 --> 00:13:48,138 that thick atmosphere is very efficient 246 00:13:48,138 --> 00:13:50,371 at redistributing the heat. 247 00:13:52,738 --> 00:13:57,638 NARRATOR: It is a world where there is no place for snow to hide. 248 00:13:57,638 --> 00:13:59,138 But there's one way to cool off on Venus, 249 00:13:59,138 --> 00:14:00,705 and that's to go up a mountain. 250 00:14:00,705 --> 00:14:06,605 ♪ ♪ 251 00:14:11,805 --> 00:14:16,138 NARRATOR: A phenomenon that we here on Earth can also relate to. 252 00:14:16,138 --> 00:14:21,805 ♪ ♪ 253 00:14:21,805 --> 00:14:24,305 PORT: Everyone knows when you go up a mountain, 254 00:14:24,305 --> 00:14:27,305 you should always pack a jacket. 255 00:14:27,305 --> 00:14:29,105 And the reason for that is because it's much colder. 256 00:14:29,105 --> 00:14:30,371 But why is it colder? 257 00:14:30,371 --> 00:14:32,871 Well, when you go up a mountain, there's less air, 258 00:14:32,871 --> 00:14:34,638 and that means there's less pressure. 259 00:14:34,638 --> 00:14:37,305 ♪ ♪ 260 00:14:37,305 --> 00:14:39,938 NARRATOR: And as the pressure decreases, 261 00:14:39,938 --> 00:14:42,505 so does the temperature. 262 00:14:44,638 --> 00:14:46,605 PORT: So, as we go up in elevation, 263 00:14:46,605 --> 00:14:48,171 we cross a threshold 264 00:14:48,171 --> 00:14:50,638 where the temperature drops low enough 265 00:14:50,638 --> 00:14:54,171 that water can be a solid. 266 00:14:54,171 --> 00:14:57,905 And this is what we call the snow line. 267 00:14:59,738 --> 00:15:01,938 NARRATOR: Venus's snow line suggests 268 00:15:01,938 --> 00:15:04,638 something may be freezing up there. 269 00:15:04,638 --> 00:15:07,405 But even its highest peaks 270 00:15:07,405 --> 00:15:11,005 are far too hot for that something to be water. 271 00:15:11,005 --> 00:15:14,138 And that points us to substances 272 00:15:14,138 --> 00:15:18,805 that solidify at much higher temperatures. 273 00:15:18,805 --> 00:15:20,505 PORT: So, instead of water, 274 00:15:20,505 --> 00:15:23,605 it actually could be something like this. 275 00:15:23,605 --> 00:15:25,971 So this is a piece of galena, 276 00:15:25,971 --> 00:15:27,838 also known as a lead sulfide. 277 00:15:27,838 --> 00:15:29,571 On Earth, it's present as a solid, 278 00:15:29,571 --> 00:15:31,171 as you can see here. 279 00:15:31,171 --> 00:15:32,538 But on Venus, 280 00:15:32,538 --> 00:15:35,805 it may only be a solid in the highlands. 281 00:15:35,805 --> 00:15:38,205 NARRATOR: Deep in Venus's lowlands, 282 00:15:38,205 --> 00:15:41,271 like valleys, 283 00:15:41,271 --> 00:15:44,305 it's hot enough for compounds like lead sulfide 284 00:15:44,305 --> 00:15:47,505 to vaporize, 285 00:15:47,505 --> 00:15:50,605 drift on the wind, 286 00:15:50,605 --> 00:15:52,505 and, as the winds flow up 287 00:15:52,505 --> 00:15:54,638 into the mountains of Maxwell Montes... 288 00:15:58,738 --> 00:16:02,405 ...the temperature drops just enough for the compounds 289 00:16:02,405 --> 00:16:05,605 to freeze out of the air. 290 00:16:09,238 --> 00:16:13,938 At 820 degrees Fahrenheit, 291 00:16:13,938 --> 00:16:16,938 Venus's atmosphere may coat its mountaintops 292 00:16:16,938 --> 00:16:18,405 not in snow, 293 00:16:18,405 --> 00:16:22,105 but in a metallic frost. 294 00:16:30,805 --> 00:16:32,638 PORT: We still don't know for sure 295 00:16:32,638 --> 00:16:35,171 if metal frost can explain the bright regions 296 00:16:35,171 --> 00:16:37,138 that we're seeing on the mountaintops. 297 00:16:37,138 --> 00:16:39,371 There's still a lot that we don't know about Venus, 298 00:16:39,371 --> 00:16:41,405 and that's because we haven't even sent a lander 299 00:16:41,405 --> 00:16:43,305 to the surface of Venus since the 1980s. 300 00:16:43,305 --> 00:16:45,171 But it's amazing to think 301 00:16:45,171 --> 00:16:47,138 that something like this could be condensing 302 00:16:47,138 --> 00:16:49,205 on the mountaintops of Venus. 303 00:16:53,105 --> 00:16:56,438 When we think of the possibility of metallic frost on Venus, 304 00:16:56,438 --> 00:16:59,871 it sounds crazy, but that's only crazy for us Earthlings. 305 00:16:59,871 --> 00:17:02,271 If you have a different atmosphere, 306 00:17:02,271 --> 00:17:06,405 you get different weather, different phenomena playing out. 307 00:17:06,405 --> 00:17:10,438 ♪ ♪ 308 00:17:12,805 --> 00:17:16,138 NARRATOR: Leaving this crushing world behind... 309 00:17:19,505 --> 00:17:21,505 ...we head out in search of an atmosphere 310 00:17:21,505 --> 00:17:26,305 that could almost be Venus's opposite. 311 00:17:28,805 --> 00:17:32,671 To reach it, we bypass our own planet. 312 00:17:39,805 --> 00:17:43,238 Passing two potato-shaped moons 313 00:17:43,238 --> 00:17:46,738 orbiting our other next-door neighbor, 314 00:17:46,738 --> 00:17:49,171 we encounter an atmosphere 315 00:17:49,171 --> 00:17:52,971 more than 10,000 times thinner than Venus's. 316 00:17:57,738 --> 00:18:00,705 With little in the way of cloud cover, 317 00:18:00,705 --> 00:18:05,371 we don't need radar to get a look at the Martian surface. 318 00:18:07,738 --> 00:18:10,405 Yet, images sent back by our orbiters 319 00:18:10,405 --> 00:18:15,005 suggest rain may have once fallen here. 320 00:18:17,271 --> 00:18:20,838 These pictures show that Mars is covered in features 321 00:18:20,838 --> 00:18:25,805 which appear to have been created by flowing water. 322 00:18:25,805 --> 00:18:27,605 DOTTIN: With such a thin atmosphere, 323 00:18:27,605 --> 00:18:29,205 it's really difficult 324 00:18:29,205 --> 00:18:31,338 to retain heat, and certainly 325 00:18:31,338 --> 00:18:32,705 not enough heat to have 326 00:18:32,705 --> 00:18:34,205 liquid water on the surface. 327 00:18:35,805 --> 00:18:39,905   NARRATOR: So if Mars was once home to lakes and rivers, 328 00:18:39,905 --> 00:18:43,371 it must have had a much thicker atmosphere in the past. 329 00:18:45,738 --> 00:18:47,405 FRAEMAN: In the early 2000s, 330 00:18:47,405 --> 00:18:49,638 we'd seen that there were hints 331 00:18:49,638 --> 00:18:50,971 that liquid water had once been 332 00:18:50,971 --> 00:18:52,038 on the Martian surface 333 00:18:52,038 --> 00:18:53,371 from our orbiters, 334 00:18:53,371 --> 00:18:54,905 but we didn't have definitive proof 335 00:18:54,905 --> 00:18:56,671 from the surface. 336 00:18:56,671 --> 00:18:59,105 So the goal of the Mars Exploration Rover mission 337 00:18:59,105 --> 00:19:01,305 was to follow the water. 338 00:19:01,305 --> 00:19:05,705 MAN: T minus five, four, three, 339 00:19:05,705 --> 00:19:08,171 two, main engine start, 340 00:19:08,171 --> 00:19:10,738 zero, and liftoff 341 00:19:10,738 --> 00:19:13,338 of the Delta rocket with Opportunity, 342 00:19:13,338 --> 00:19:15,005 a chance to explore 343 00:19:15,005 --> 00:19:18,938 and unlock the secrets of our neighboring planet. 344 00:19:18,938 --> 00:19:21,538 FRAEMAN: I was 16 years old when Spirit and Opportunity 345 00:19:21,538 --> 00:19:23,305 launched and landed on Mars. 346 00:19:23,305 --> 00:19:26,005 But I had the amazing opportunity 347 00:19:26,005 --> 00:19:29,005 through an outreach program to actually go to be at NASA, 348 00:19:29,005 --> 00:19:30,771 at the Jet Propulsion Laboratory, 349 00:19:30,771 --> 00:19:32,071 when the rovers landed. 350 00:19:32,071 --> 00:19:34,305 MAN: Getting a bounce to signal. 351 00:19:34,305 --> 00:19:36,371 (cheering) 352 00:19:36,371 --> 00:19:38,571 FRAEMAN: And I was in the room with the science team 353 00:19:38,571 --> 00:19:39,971 when Opportunity landed on Mars, 354 00:19:39,971 --> 00:19:43,338 and it was the most amazing experience. 355 00:19:43,338 --> 00:19:45,105 (cheering and applauding) 356 00:19:45,105 --> 00:19:47,638 NARRATOR: Two rovers named Spirit and Opportunity 357 00:19:47,638 --> 00:19:50,138 were sent to opposite sides of the Red Planet 358 00:19:50,138 --> 00:19:53,171 to search for definitive proof 359 00:19:53,171 --> 00:19:56,338 that Mars's dry landscape 360 00:19:56,338 --> 00:19:57,938 was once a water world. 361 00:20:01,805 --> 00:20:05,338 At first glance, modern Mars doesn't appear 362 00:20:05,338 --> 00:20:08,838 to be a very dynamic place. 363 00:20:08,838 --> 00:20:10,605 With an average surface temperature 364 00:20:10,605 --> 00:20:13,538 of about -80 degrees Fahrenheit 365 00:20:13,538 --> 00:20:17,105 and an atmosphere just one percent as thick as Earth's, 366 00:20:17,105 --> 00:20:19,571 it is a freezing desert. 367 00:20:21,871 --> 00:20:26,271 Typically, we think of Mars as this dead world. 368 00:20:26,271 --> 00:20:29,805 But we do see changes on the surface over time. 369 00:20:32,605 --> 00:20:36,971 NARRATOR: Strange, overlapping lines, 370 00:20:36,971 --> 00:20:40,771 often dozens of feet wide, 371 00:20:40,771 --> 00:20:44,371 can stretch for miles. 372 00:20:48,738 --> 00:20:51,771 Unlike many of Mars's features, 373 00:20:51,771 --> 00:20:56,205 these are not relics. 374 00:20:56,205 --> 00:21:00,671 We see them appear and disappear. 375 00:21:05,805 --> 00:21:09,005 What are these bizarre, shape-shifting patterns? 376 00:21:09,005 --> 00:21:12,405 ♪ ♪ 377 00:21:16,205 --> 00:21:20,038 In January 2004, Spirit and Opportunity 378 00:21:20,038 --> 00:21:23,405 began to investigate Mars. 379 00:21:23,405 --> 00:21:28,805 ♪ ♪ 380 00:21:28,805 --> 00:21:33,438 But their mission wasn't expected to last very long. 381 00:21:33,438 --> 00:21:35,405 GUPTA: Mars is covered in dust. 382 00:21:35,405 --> 00:21:37,305 It gets everywhere, 383 00:21:37,305 --> 00:21:40,205 including on the solar panels of Mars rovers. 384 00:21:40,205 --> 00:21:43,771   As the solar panels got dustier and dustier, 385 00:21:43,771 --> 00:21:45,471 the power levels that the rover would have 386 00:21:45,471 --> 00:21:47,338 would get lower and lower and lower, 387 00:21:47,338 --> 00:21:49,638 and eventually, they would just stop working. 388 00:21:51,305 --> 00:21:53,171 NARRATOR: The team hoped the rovers 389 00:21:53,171 --> 00:21:55,005 would last at least three months, 390 00:21:55,005 --> 00:21:58,738 a feat they surpassed. 391 00:22:00,805 --> 00:22:03,538 But, as the months wore on, 392 00:22:03,538 --> 00:22:07,038 the power levels continued to drop. 393 00:22:08,671 --> 00:22:10,405 What was really exciting 394 00:22:10,405 --> 00:22:11,838 was, at one point in the mission, 395 00:22:11,838 --> 00:22:14,005 as we were seeing the power levels 396 00:22:14,005 --> 00:22:16,305 getting lower and lower and lower, 397 00:22:16,305 --> 00:22:18,971 all of a sudden, the power levels were 398 00:22:18,971 --> 00:22:20,671 back up high again. 399 00:22:20,671 --> 00:22:25,338 ♪ ♪ 400 00:22:25,338 --> 00:22:28,238 Almost as high as they were when the rovers had landed. 401 00:22:29,805 --> 00:22:33,038 And you can take a look at the before and after pictures, 402 00:22:33,038 --> 00:22:35,538 and you can see that it looks like the solar panels 403 00:22:35,538 --> 00:22:38,905 have just been wiped clean. 404 00:22:38,905 --> 00:22:41,038 You could call up AAA and send them to Mars 405 00:22:41,038 --> 00:22:42,871 with the rag to clean everything off. 406 00:22:42,871 --> 00:22:44,538 They couldn't have done a better job. 407 00:22:47,738 --> 00:22:50,938 NARRATOR: Finally, a clue to what might be happening 408 00:22:50,938 --> 00:22:53,971 was spotted by Spirit's Navcam. 409 00:22:59,571 --> 00:23:03,805 ♪ ♪ 410 00:23:03,805 --> 00:23:06,105 In the mid-afternoon sun... 411 00:23:06,105 --> 00:23:07,571 ♪ ♪ 412 00:23:07,571 --> 00:23:09,505 ...heating of the Martian surface 413 00:23:09,505 --> 00:23:13,705 creates towering vortices, 414 00:23:13,705 --> 00:23:17,071 which can grow miles high. 415 00:23:20,838 --> 00:23:23,805 Dust devils. 416 00:23:23,805 --> 00:23:26,371 GUPTA: I imagine it would be absolutely terrifying 417 00:23:26,371 --> 00:23:28,971 to be standing on the surface of Mars 418 00:23:28,971 --> 00:23:31,771 and see one of these dust devils coming straight at you. 419 00:23:33,805 --> 00:23:35,938 FRAEMAN: You might think that there was this 420 00:23:35,938 --> 00:23:39,205 tornado-force wind coming towards the rover, 421 00:23:39,205 --> 00:23:42,005 and it might pick the rover up and spin them around 422 00:23:42,005 --> 00:23:43,638 and do all sorts of horrible things. 423 00:23:43,638 --> 00:23:45,338 But in reality, 424 00:23:45,338 --> 00:23:48,138 the Martian atmosphere is actually very, very thin, 425 00:23:48,138 --> 00:23:50,771 and so you can have a dust devil pass over you 426 00:23:50,771 --> 00:23:52,638 and, and you would barely even notice it. 427 00:23:52,638 --> 00:23:54,805 But even though a Martian dust devil 428 00:23:54,805 --> 00:23:56,505 might not be able to pick you up, 429 00:23:56,505 --> 00:23:58,605 it can certainly pick dust up. 430 00:24:00,805 --> 00:24:02,538 NARRATOR: It's thought that 431 00:24:02,538 --> 00:24:06,005 as these whirlwinds traveled over the rovers, 432 00:24:06,005 --> 00:24:08,538 they sucked dust off the solar panels, 433 00:24:08,538 --> 00:24:11,471 like a vacuum. 434 00:24:11,471 --> 00:24:15,738 So a mission expected to last just a few months 435 00:24:15,738 --> 00:24:18,538 was extended again, 436 00:24:18,538 --> 00:24:22,771 and again, 437 00:24:22,771 --> 00:24:25,071 and again. 438 00:24:26,805 --> 00:24:28,738 But the cleaning power of the dust devils 439 00:24:28,738 --> 00:24:31,471 doesn't just work on rovers. 440 00:24:31,471 --> 00:24:35,505 (wind roaring) 441 00:24:35,505 --> 00:24:39,338 ♪ ♪ 442 00:24:39,338 --> 00:24:41,805 As they travel, 443 00:24:41,805 --> 00:24:43,105 these huge vortices 444 00:24:43,105 --> 00:24:46,271 suck up dust from Mars's surface, 445 00:24:46,271 --> 00:24:50,105 exposing the darker bedrock beneath. 446 00:24:52,738 --> 00:24:56,105 Leaving trails so large, 447 00:24:56,105 --> 00:24:59,271 we can see them clearly from space. 448 00:24:59,271 --> 00:25:02,805 ♪ ♪ 449 00:25:02,805 --> 00:25:06,271 There are no Martians creating the lines. 450 00:25:08,505 --> 00:25:13,505 The culprit is the Martian atmosphere. 451 00:25:15,805 --> 00:25:19,538 Dust devils might create the tracks, 452 00:25:19,538 --> 00:25:24,305 but something else wipes them away. 453 00:25:24,305 --> 00:25:26,805 ♪ ♪ 454 00:25:26,805 --> 00:25:28,571 Just like Earth, 455 00:25:28,571 --> 00:25:32,838 Mars has a tilt that gives it seasons. 456 00:25:32,838 --> 00:25:36,805 Summer in one hemisphere means winter in the other. 457 00:25:40,805 --> 00:25:43,105 And with no oceans or thick atmosphere 458 00:25:43,105 --> 00:25:45,605 to help spread heat around the globe, 459 00:25:45,605 --> 00:25:48,971 an extreme temperature difference. 460 00:25:51,438 --> 00:25:54,838 So here, dust helps drive the action. 461 00:25:56,271 --> 00:26:00,805 ♪ ♪ 462 00:26:00,805 --> 00:26:04,305 As summer arrives in the southern hemisphere, 463 00:26:04,305 --> 00:26:07,371 warmer temperatures drive stronger winds, 464 00:26:07,371 --> 00:26:10,738 which kick dust up into the air. 465 00:26:12,438 --> 00:26:16,605 The dust absorbs sunlight and heats the air around it... 466 00:26:19,671 --> 00:26:21,338 ...further strengthening the winds, 467 00:26:21,338 --> 00:26:25,905 which lift even more dust... 468 00:26:30,838 --> 00:26:35,338 ...until a storm forms... 469 00:26:37,905 --> 00:26:43,005 ...wiping away dust devil trails. 470 00:26:43,005 --> 00:26:47,238 And these storms can combine and grow so large... 471 00:26:51,005 --> 00:26:55,505 ...that they engulf the entire planet, 472 00:26:55,505 --> 00:26:59,705 sometimes blocking more than 99% of the incoming sunlight 473 00:26:59,705 --> 00:27:03,138 from reaching the surface... 474 00:27:04,905 --> 00:27:09,205 ...and the solar panels of Mars rovers. 475 00:27:11,938 --> 00:27:17,105 In May 2018, with Opportunity still active on the surface, 476 00:27:17,105 --> 00:27:20,571 a storm began to build. 477 00:27:20,571 --> 00:27:22,005 FRAEMAN: It only took a couple of days 478 00:27:22,005 --> 00:27:25,638 of seeing the skies get darker and darker and darker 479 00:27:25,638 --> 00:27:27,338 before we started to realize that, 480 00:27:27,338 --> 00:27:29,905 "Oh, this is actually, this is a really bad one." 481 00:27:29,905 --> 00:27:32,205 Um, and by the end of the week, 482 00:27:32,205 --> 00:27:34,971 we knew that this was the worst dust storm 483 00:27:34,971 --> 00:27:36,905 that we were ever gonna have to survive. 484 00:27:36,905 --> 00:27:40,205 We knew we were probably gonna lose communication with Oppy. 485 00:27:40,205 --> 00:27:43,371 So we let her go dark 486 00:27:43,371 --> 00:27:47,305 and we just waited and waited. 487 00:27:47,305 --> 00:27:50,705 NARRATOR: Mars's low gravity means the dust in the air 488 00:27:50,705 --> 00:27:54,805 can remain there for months. 489 00:27:54,805 --> 00:27:57,571 ♪ ♪ 490 00:27:57,571 --> 00:27:59,705 Eventually, with so little sunlight 491 00:27:59,705 --> 00:28:02,938 reaching the Martian surface, 492 00:28:02,938 --> 00:28:05,538 the temperature differences which fueled the storm 493 00:28:05,538 --> 00:28:08,371 are dampened, 494 00:28:08,371 --> 00:28:11,138 cutting off its own energy supply, 495 00:28:11,138 --> 00:28:15,771 and the dust finally settles. 496 00:28:15,771 --> 00:28:18,771 But by the end of 2018, 497 00:28:18,771 --> 00:28:22,205 even after the Martian skies had cleared, 498 00:28:22,205 --> 00:28:25,771 there was no signal from Opportunity. 499 00:28:25,771 --> 00:28:27,705 And with winter looming, 500 00:28:27,705 --> 00:28:30,138 it was unlikely the rover's electronics 501 00:28:30,138 --> 00:28:32,071 would survive the cold. 502 00:28:34,038 --> 00:28:36,671 ♪ ♪ 503 00:28:36,671 --> 00:28:39,071 On February 13, 2019, 504 00:28:39,071 --> 00:28:43,705 NASA declared its mission complete. 505 00:28:43,705 --> 00:28:45,671 FRAEMAN: I know it sounds weird, 506 00:28:45,671 --> 00:28:47,738 'cause it's a robot... (laughs) 507 00:28:47,738 --> 00:28:49,438 ...but it's sort of the same feeling you have 508 00:28:49,438 --> 00:28:51,205 when you might lose a loved one 509 00:28:51,205 --> 00:28:53,471 who's lived a very full life. 510 00:28:53,471 --> 00:28:56,438 I was a high school student when they landed. 511 00:28:56,438 --> 00:28:58,571 By the time Opportunity's mission ended, 512 00:28:58,571 --> 00:29:01,605 I had gone to college, I had gotten a Ph.D., 513 00:29:01,605 --> 00:29:03,071 I had done a post-doc, 514 00:29:03,071 --> 00:29:05,371 and then I had been hired by NASA 515 00:29:05,371 --> 00:29:08,771 to work on this very same Opportunity rover 516 00:29:08,771 --> 00:29:10,938 that had inspired me when I was a high school student. 517 00:29:13,338 --> 00:29:17,338 NARRATOR: Sent to Mars to hunt for ancient evidence of water, 518 00:29:17,338 --> 00:29:22,805 Opportunity not only succeeded, but exceeded expectations, 519 00:29:22,805 --> 00:29:27,171 lasting over 14 years thanks to the Martian weather. 520 00:29:30,205 --> 00:29:35,538 ♪ ♪ 521 00:29:35,538 --> 00:29:37,338 Despite their differences, 522 00:29:37,338 --> 00:29:43,271 Venus and Mars have one thing in common. 523 00:29:43,271 --> 00:29:46,605 Their weather is powered by solar energy. 524 00:29:50,305 --> 00:29:52,238 But beyond the asteroid belt... 525 00:29:55,571 --> 00:30:00,338 ...ruled by the dwarf planet Ceres, 526 00:30:00,338 --> 00:30:03,471 the sun's influence wanes. 527 00:30:05,638 --> 00:30:09,305 And yet, the next planet we encounter 528 00:30:09,305 --> 00:30:11,038 is a storm world... 529 00:30:13,238 --> 00:30:16,271 ...on the grandest scale. 530 00:30:26,771 --> 00:30:30,038 PITTS: If you were just arriving at Jupiter in a spacecraft, 531 00:30:30,038 --> 00:30:32,371 you would be stunned by what you see. 532 00:30:32,371 --> 00:30:33,971 First of all, there's the size. 533 00:30:35,205 --> 00:30:41,005 You can fit 1,300 planet Earths inside Jupiter. 534 00:30:41,005 --> 00:30:42,371 In fact, you could fit all of the planets 535 00:30:42,371 --> 00:30:44,138 in the solar system inside Jupiter 536 00:30:44,138 --> 00:30:45,638 and still have room to spare. 537 00:30:48,538 --> 00:30:53,005 NARRATOR: Jupiter is a gas giant 538 00:30:53,005 --> 00:30:56,871 on which storms can grow bigger than Earth itself. 539 00:31:00,105 --> 00:31:04,138 Since 2016, NASA's Juno spacecraft 540 00:31:04,138 --> 00:31:08,605 has been exploring this gargantuan planet 541 00:31:08,605 --> 00:31:12,071 and found its weather is anything but subtle. 542 00:31:12,071 --> 00:31:17,171 (thunder rumbling) 543 00:31:17,171 --> 00:31:20,705 Jupiter's thunderstorms can produce lightning bolts 544 00:31:20,705 --> 00:31:24,638 ten times more energetic than anything recorded on Earth. 545 00:31:24,638 --> 00:31:27,338 (thunder rumbling, lightning crackling) 546 00:31:27,338 --> 00:31:31,671 Most of the flashes lie beneath thick ammonia ice clouds. 547 00:31:34,071 --> 00:31:37,705 But the most powerful storms break free, 548 00:31:37,705 --> 00:31:41,638 soaring to the edge of space. 549 00:31:41,638 --> 00:31:45,138 (thunder booming, lightning crackling) 550 00:31:45,138 --> 00:31:49,771 The scale of Jupiter's storms may be hard to comprehend. 551 00:31:51,671 --> 00:31:53,838 But Juno found that the frequency 552 00:31:53,838 --> 00:31:56,771 of its lightning strikes is remarkably similar 553 00:31:56,771 --> 00:32:00,471 to Earth's thunderclouds. 554 00:32:03,838 --> 00:32:06,171 DRANSFIELD: It's odd that lightning is such a common occurrence 555 00:32:06,171 --> 00:32:07,171 here on Earth, 556 00:32:07,171 --> 00:32:08,505 but it's taken us centuries 557 00:32:08,505 --> 00:32:10,738 to really understand how it works. 558 00:32:10,738 --> 00:32:14,005   (thunder claps, lightning crackles) 559 00:32:14,005 --> 00:32:15,971 NARRATOR: The substance responsible 560 00:32:15,971 --> 00:32:21,271 for our planet's thunderstorms is water. 561 00:32:21,271 --> 00:32:22,405 The way that lightning gets formed 562 00:32:22,405 --> 00:32:24,438 is that it relies on collisions 563 00:32:24,438 --> 00:32:28,371 between icy particles and watery droplets. 564 00:32:28,371 --> 00:32:32,471   And as the watery droplets are moving upwards and colliding 565 00:32:32,471 --> 00:32:34,571 with the icy particles that are falling downwards, 566 00:32:34,571 --> 00:32:39,738 they're exchanging charge with each other. 567 00:32:39,738 --> 00:32:42,338 So you get a separation of charge 568 00:32:42,338 --> 00:32:45,005 from the top of a cloud to the bottom of the cloud. 569 00:32:46,405 --> 00:32:48,205 And as that separation of charge 570 00:32:48,205 --> 00:32:50,338 becomes bigger and bigger and bigger, 571 00:32:50,338 --> 00:32:52,671 eventually, the atmosphere can't cope anymore. 572 00:32:52,671 --> 00:32:54,305 PITTS: And when that occurs, 573 00:32:54,305 --> 00:32:56,738 now a flow of electricity can happen. 574 00:32:56,738 --> 00:33:01,371 (lightning crackling) 575 00:33:01,371 --> 00:33:05,371 NARRATOR: A single bolt of lightning is so powerful, 576 00:33:05,371 --> 00:33:08,271 it can heat the surrounding air 577 00:33:08,271 --> 00:33:12,005 to temperatures greater than the surface of the sun. 578 00:33:12,005 --> 00:33:17,038 ♪ ♪ 579 00:33:21,005 --> 00:33:26,338 So how can clouds produce so much energy? 580 00:33:26,338 --> 00:33:29,405 HEIDI BECKER: For all of our history, lightning has been 581 00:33:29,405 --> 00:33:32,071 something that humans have feared. 582 00:33:32,071 --> 00:33:36,071 But what's driving it really is the water cycle. 583 00:33:36,071 --> 00:33:38,238 The sun heats the water, 584 00:33:38,238 --> 00:33:40,871 it evaporates, becomes water vapor, 585 00:33:40,871 --> 00:33:42,871 rises up into the atmosphere, 586 00:33:42,871 --> 00:33:45,338 cools, and eventually becomes 587 00:33:45,338 --> 00:33:47,371 water droplets in clouds. 588 00:33:47,371 --> 00:33:49,671 And intuitively, as humans, 589 00:33:49,671 --> 00:33:52,305 we actually understand what's happening very well. 590 00:33:52,305 --> 00:33:55,005 We wet our hand, 591 00:33:55,005 --> 00:33:56,805 and it feels cold because 592 00:33:56,805 --> 00:34:00,238 the water is stealing energy from our hand, 593 00:34:00,238 --> 00:34:02,205 breaking up the water molecules, 594 00:34:02,205 --> 00:34:03,571 turning them into water vapor 595 00:34:03,571 --> 00:34:04,571 so that they can 596 00:34:04,571 --> 00:34:05,805 rise up into the sky. 597 00:34:07,371 --> 00:34:10,405 NARRATOR: Water evaporation requires energy, 598 00:34:10,405 --> 00:34:15,438 whether it's from our body heat or the sun. 599 00:34:15,438 --> 00:34:20,405 As water turns from a liquid to a gas, it stores this energy. 600 00:34:21,838 --> 00:34:26,071 And when it turns back into a liquid, in the form of clouds, 601 00:34:26,071 --> 00:34:30,805 it releases this energy back into the atmosphere. 602 00:34:30,805 --> 00:34:32,671 What's kind of incredible to believe 603 00:34:32,671 --> 00:34:36,371 is that a, a small little cumulus cloud that you might see 604 00:34:36,371 --> 00:34:39,371 floating in the sky, looking so graceful and peaceful, 605 00:34:39,371 --> 00:34:41,271 is actually the result 606 00:34:41,271 --> 00:34:43,905 of an enormous amount of energy being released. 607 00:34:43,905 --> 00:34:47,505 It's the same as hundreds of tons of TNT. 608 00:34:49,238 --> 00:34:51,238 NARRATOR: And for an average thunderstorm, 609 00:34:51,238 --> 00:34:55,338 the energy released is equivalent to a nuclear blast. 610 00:34:57,438 --> 00:35:00,838 It's this huge release of heat 611 00:35:00,838 --> 00:35:04,271 that makes thunderclouds so turbulent, 612 00:35:04,271 --> 00:35:07,405 causing the countless icy collisions... 613 00:35:07,405 --> 00:35:09,771 (thunder rumbling, lightning crackling) 614 00:35:12,238 --> 00:35:14,705 ...which power Earth's lightning. 615 00:35:18,571 --> 00:35:21,505 Several missions to Jupiter have detected water 616 00:35:21,505 --> 00:35:23,905 in its atmosphere. 617 00:35:25,438 --> 00:35:28,771 But the planet receives just four percent of the sunlight 618 00:35:28,771 --> 00:35:32,171 that reaches Earth, 619 00:35:32,171 --> 00:35:36,538 too little energy to account for its ferocious lightning storms. 620 00:35:38,571 --> 00:35:42,138 ♪ ♪ 621 00:35:42,138 --> 00:35:46,305 But looking at the planet in infrared 622 00:35:46,305 --> 00:35:49,538 reveals a different source of energy. 623 00:35:49,538 --> 00:35:52,338 Jupiter is radiating heat, 624 00:35:52,338 --> 00:35:56,705 almost twice the energy it receives from the sun. 625 00:35:59,405 --> 00:36:02,671 FLETCHER: So, Jupiter itself is slowly cooling, 626 00:36:02,671 --> 00:36:05,705 and has been over the entire age of the solar system. 627 00:36:05,705 --> 00:36:10,238 And as it's cooling, the entire gas giant is slowly shrinking. 628 00:36:10,238 --> 00:36:13,538 And as it shrinks, it's relinquishing that energy 629 00:36:13,538 --> 00:36:16,805 that was left over from when Jupiter was born. 630 00:36:16,805 --> 00:36:18,238 That's enough to power 631 00:36:18,238 --> 00:36:20,305 the gargantuan storms that we see. 632 00:36:20,305 --> 00:36:24,371 (crackling) 633 00:36:24,371 --> 00:36:26,871 NARRATOR: This internal heat means water. 634 00:36:26,871 --> 00:36:32,071 The chemical powering Earth's storms 635 00:36:32,071 --> 00:36:35,238 also powers storms on Jupiter. 636 00:36:38,005 --> 00:36:41,205 In vapor form, water rises, 637 00:36:41,205 --> 00:36:44,605 carrying heat energy from deep inside the planet... 638 00:36:47,238 --> 00:36:52,405 ...until it reaches a place under the ammonia ice clouds... 639 00:36:54,038 --> 00:36:55,605 (thunder crashes) 640 00:36:55,605 --> 00:36:56,871 ...where it's cool enough 641 00:36:56,871 --> 00:36:59,571 to condense into liquid water droplets 642 00:36:59,571 --> 00:37:02,671 and ice crystals. 643 00:37:04,438 --> 00:37:07,938 The energy released by this condensing water 644 00:37:07,938 --> 00:37:11,571 powers the growth of violent thunderstorms. 645 00:37:15,305 --> 00:37:18,138 But because Jupiter has so much internal heat 646 00:37:18,138 --> 00:37:21,205 that's trying to escape, 647 00:37:21,205 --> 00:37:25,671 in some places, enough energy is released by condensing water... 648 00:37:27,538 --> 00:37:32,271 ...that ice crystals are swept up into the ice clouds above. 649 00:37:37,538 --> 00:37:42,671 Here, ammonia acts as an antifreeze... 650 00:37:44,338 --> 00:37:46,505 ...allowing thunderclouds to grow 651 00:37:46,505 --> 00:37:50,538 to more than 35 miles tall 652 00:37:50,538 --> 00:37:54,938 and lightning to strike at minus 150 degrees Fahrenheit. 653 00:37:56,638 --> 00:38:04,005 ♪ ♪ 654 00:38:04,005 --> 00:38:07,038 Jupiter and Earth may be worlds apart, 655 00:38:07,038 --> 00:38:10,438 but both play host to lightning storms 656 00:38:10,438 --> 00:38:15,105 which are driven by water. 657 00:38:17,605 --> 00:38:19,205 I just find it wicked cool that on a planet 658 00:38:19,205 --> 00:38:20,738 as different as Jupiter, 659 00:38:20,738 --> 00:38:23,705 the weather is being formed in much the same way 660 00:38:23,705 --> 00:38:24,838 as it is here on Earth. 661 00:38:29,805 --> 00:38:33,538 NARRATOR: However, there is one more place in the solar system 662 00:38:33,538 --> 00:38:38,471 with even more Earth-like weather. 663 00:38:38,471 --> 00:38:40,938 PITTS: But what's really interesting and exciting is, 664 00:38:40,938 --> 00:38:43,438 the liquid that's being shifted around 665 00:38:43,438 --> 00:38:44,705 isn't water. 666 00:38:46,405 --> 00:38:49,938   NARRATOR: To find it, we travel 400 million miles farther 667 00:38:49,938 --> 00:38:52,438 from the sun 668 00:38:52,438 --> 00:38:57,671 and encounter another gas giant. 669 00:38:57,671 --> 00:39:00,538 But this isn't our destination. 670 00:39:00,538 --> 00:39:03,771 ♪ ♪ 671 00:39:03,771 --> 00:39:09,238 Saturn is orbited by an amazing variety of moons, 672 00:39:09,238 --> 00:39:13,538 so many that it can be hard to keep track of them all. 673 00:39:17,038 --> 00:39:18,971 Iapetus, Rhea, 674 00:39:18,971 --> 00:39:20,605 Enceladus... 675 00:39:20,605 --> 00:39:23,705 GAO: Tethys, Mimas, Epimethys. 676 00:39:23,705 --> 00:39:28,705 Helene, Prometheus, uh, Calypso. 677 00:39:28,705 --> 00:39:30,538 Shoot, there's that really funny one. 678 00:39:30,538 --> 00:39:31,638 Phoebe. 679 00:39:31,638 --> 00:39:33,505 There's Pan, which is really cool 680 00:39:33,505 --> 00:39:35,105 because it looks like a ravioli. 681 00:39:35,105 --> 00:39:37,405 GRINSPOON (laughing): I didn't cram for this. 682 00:39:37,405 --> 00:39:38,838 Did I mention Mimas? 683 00:39:38,838 --> 00:39:40,471 GRINSPOON: What's the little, really weird... 684 00:39:40,471 --> 00:39:41,671 Hyperion. 685 00:39:41,671 --> 00:39:43,438 Uh... (chuckles) 686 00:39:43,438 --> 00:39:44,638 Um... 687 00:39:44,638 --> 00:39:46,638 Um, uh, let's see. 688 00:39:46,638 --> 00:39:49,271 And a bunch more. (laughs) 689 00:39:50,271 --> 00:39:53,138 NARRATOR: But one is special. 690 00:39:53,138 --> 00:39:56,905 More than 20 times the mass of all the others combined. 691 00:39:59,238 --> 00:40:03,605 It's the only moon in the solar system with a thick atmosphere. 692 00:40:13,271 --> 00:40:18,038 In November 1980, NASA's Voyager 1 spacecraft 693 00:40:18,038 --> 00:40:20,838 revealed Saturn and its many moons 694 00:40:20,838 --> 00:40:24,371 in greater detail than ever before. 695 00:40:24,371 --> 00:40:27,805 PITTS: When the Voyager 1 spacecraft flew by Titan, 696 00:40:27,805 --> 00:40:29,605 we could see that it had an atmosphere, 697 00:40:29,605 --> 00:40:31,071 and a thick atmosphere, 698 00:40:31,071 --> 00:40:35,571 but this was only a tantalizing view. 699 00:40:35,571 --> 00:40:37,538 SOTO: The images from Voyager of Titan 700 00:40:37,538 --> 00:40:40,805 were exciting but also, in a way, 701 00:40:40,805 --> 00:40:42,338 infuriating, right? 702 00:40:42,338 --> 00:40:46,405 It confirmed everything that we had thought about Titan, 703 00:40:46,405 --> 00:40:48,671 but it didn't allow us to see down to the surface. 704 00:40:48,671 --> 00:40:51,071 With Voyager, we could do some remote sensing 705 00:40:51,071 --> 00:40:55,271   and start to tell that the surface was, was very cold, 706 00:40:55,271 --> 00:40:57,238 but in the right temperature range 707 00:40:57,238 --> 00:41:00,171 so that you might actually have liquid methane on the surface. 708 00:41:00,171 --> 00:41:02,305 And so we, we just knew that we had to go back 709 00:41:02,305 --> 00:41:05,971 and, and learn more. 710 00:41:05,971 --> 00:41:11,271 MAN: Five, four, three, two, one, 711 00:41:11,271 --> 00:41:14,405 and liftoff of the Cassini spacecraft 712 00:41:14,405 --> 00:41:17,538 on a billion-mile trek to Saturn. 713 00:41:17,538 --> 00:41:19,938 NARRATOR: The legendary Cassini-Huygens mission 714 00:41:19,938 --> 00:41:23,471 took almost seven years to reach Saturn 715 00:41:23,471 --> 00:41:25,538 and spent over a decade 716 00:41:25,538 --> 00:41:29,071 exploring the planet and its moons. 717 00:41:29,071 --> 00:41:32,471 And on December 25, 2004, 718 00:41:32,471 --> 00:41:36,138 nearly a quarter of a century after Voyager 1's flyby... 719 00:41:38,005 --> 00:41:43,238 ...the Huygens probe detached from Cassini 720 00:41:43,238 --> 00:41:47,138 in a bid to become the first probe ever to land on a body 721 00:41:47,138 --> 00:41:50,138 in the outer solar system. 722 00:41:50,138 --> 00:41:52,438 ♪ ♪ 723 00:41:52,438 --> 00:41:54,605 You know, there was so much anticipation 724 00:41:54,605 --> 00:41:56,705 of what that surface might be like. 725 00:41:56,705 --> 00:41:59,838 But I think in none of our wildest dreams 726 00:41:59,838 --> 00:42:03,605 was the surface of Titan as interesting and beautiful 727 00:42:03,605 --> 00:42:07,171 and exotic and exciting as it turns out to actually be. 728 00:42:15,838 --> 00:42:19,905 NARRATOR: During its two-and-a-half-hour descent to Titan, 729 00:42:19,905 --> 00:42:23,971 Huygens captured images of intricate ridges, 730 00:42:23,971 --> 00:42:26,705 deep gullies, 731 00:42:26,705 --> 00:42:30,938 and, perhaps most strikingly, river channels. 732 00:42:34,905 --> 00:42:38,371 GRINSPOON: It was truly like a dream, but there they are. 733 00:42:38,371 --> 00:42:39,505 These are real pictures coming 734 00:42:39,505 --> 00:42:41,538 from our first-ever descent to Titan. 735 00:42:41,538 --> 00:42:44,605 And, uh, it's unmistakable what we're seeing. 736 00:42:44,605 --> 00:42:46,571 And I'll, I'll just never forget that moment. 737 00:42:47,938 --> 00:42:49,405 PITTS: It's a moon! 738 00:42:49,405 --> 00:42:51,971 It's a moon that looks like this! 739 00:42:51,971 --> 00:42:54,471 Not a planet. 740 00:42:54,471 --> 00:42:58,705 How do you, how do you have these fluvial erosional features 741 00:42:58,705 --> 00:43:00,805 on the moon of a planet? 742 00:43:00,805 --> 00:43:03,605 ♪ ♪ 743 00:43:03,605 --> 00:43:09,305 NARRATOR: The team had designed Huygens to float, 744 00:43:09,305 --> 00:43:14,838 but it landed in what appeared to be an empty riverbed. 745 00:43:14,838 --> 00:43:19,205 And the river channels it imaged during its descent were dry. 746 00:43:21,838 --> 00:43:24,071 The probe continued to transmit data 747 00:43:24,071 --> 00:43:27,071 from Titan's surface for more than an hour 748 00:43:27,071 --> 00:43:32,071 before its breathtaking mission came to an end. 749 00:43:32,071 --> 00:43:36,405 But Cassini continued to explore the surface from afar. 750 00:43:38,905 --> 00:43:43,705 ♪ ♪ 751 00:43:43,705 --> 00:43:47,705 It saw a landscape of rolling dune fields, 752 00:43:47,705 --> 00:43:51,405 vast plains, 753 00:43:51,405 --> 00:43:55,105 and more dried-up rivers. 754 00:43:55,105 --> 00:43:58,005 It seemed Titan was a desert world. 755 00:44:01,038 --> 00:44:06,705 But in 2006, after many months of searching... 756 00:44:09,338 --> 00:44:11,805 ...Cassini's radar instrument found 757 00:44:11,805 --> 00:44:17,338 what everyone had been waiting for: 758 00:44:17,338 --> 00:44:21,171 lakes and seas of liquid methane at the north pole. 759 00:44:23,171 --> 00:44:26,938 Titan's equatorial region may be a desert, 760 00:44:26,938 --> 00:44:33,038 but Cassini had proved that its poles were anything but. 761 00:44:33,038 --> 00:44:34,405 FLETCHER: So that difference we could see 762 00:44:34,405 --> 00:44:36,138 between the deserts 763 00:44:36,138 --> 00:44:37,805 down around the equatorial region 764 00:44:37,805 --> 00:44:39,138 and the seas that were present 765 00:44:39,138 --> 00:44:40,771 up at high latitudes 766 00:44:40,771 --> 00:44:42,371 had us scratching our heads. 767 00:44:44,005 --> 00:44:45,738 NARRATOR: What could be carving channels 768 00:44:45,738 --> 00:44:51,038 over a thousand miles away from the poles? 769 00:44:58,038 --> 00:45:00,705 MACKENZIE: We think about deserts as dry places, 770 00:45:00,705 --> 00:45:03,838 and most of the time they are, but they're carved, 771 00:45:03,838 --> 00:45:07,671 they're shaped, they're defined by these seasonal rainstorms 772 00:45:07,671 --> 00:45:10,205 that may happen only once or twice a year. 773 00:45:11,371 --> 00:45:16,038 The question is, could something similar be happening on Titan? 774 00:45:16,038 --> 00:45:17,838 Saturn happens to be tilted 775 00:45:17,838 --> 00:45:20,405 at about the same angle that the Earth is. 776 00:45:20,405 --> 00:45:21,971 So as it's going around the sun, 777 00:45:21,971 --> 00:45:25,605 it experiences seasons much like we do here on the Earth. 778 00:45:25,605 --> 00:45:28,105 But it takes Saturn and Titan a lot longer 779 00:45:28,105 --> 00:45:30,171 to go around the sun than we do. 780 00:45:30,171 --> 00:45:32,938 It takes 29-and-a-half years. 781 00:45:32,938 --> 00:45:35,738 Titan shares the same orbital plane as Saturn. 782 00:45:35,738 --> 00:45:38,005 And so it also experiences seasons 783 00:45:38,005 --> 00:45:40,605 as it's going around the sun. 784 00:45:40,605 --> 00:45:42,671 If we take the southern hemisphere, for example, 785 00:45:42,671 --> 00:45:45,305 there are seven years of summer 786 00:45:45,305 --> 00:45:47,805 where the southern hemisphere is pointed 787 00:45:47,805 --> 00:45:50,571 towards the sun and receiving more energy. 788 00:45:50,571 --> 00:45:52,138 That extra bit of energy, 789 00:45:52,138 --> 00:45:54,305 even though it's only a 100th 790 00:45:54,305 --> 00:45:56,405 of what we experience here on the Earth, 791 00:45:56,405 --> 00:45:59,771 is enough to pump the atmosphere full of methane, 792 00:45:59,771 --> 00:46:01,138 thanks to evaporation 793 00:46:01,138 --> 00:46:03,071 from the lakes in the south pole. 794 00:46:03,071 --> 00:46:07,771 ♪ ♪ 795 00:46:07,771 --> 00:46:11,105 NARRATOR: Cassini saw this happening. 796 00:46:11,105 --> 00:46:14,671 It flew by Titan during the southern summer... 797 00:46:17,405 --> 00:46:23,371 ...and saw methane clouds swirling around the south pole. 798 00:46:24,505 --> 00:46:27,538 But the clouds didn't stay there. 799 00:46:31,271 --> 00:46:34,471 MACKENZIE: In 2010, there was a giant cloud 800 00:46:34,471 --> 00:46:38,038 that formed over the equatorial region in the shape of an arrow. 801 00:46:38,038 --> 00:46:40,138 And as it moved across the surface of Titan, 802 00:46:40,138 --> 00:46:43,671 we saw that land that was bright before 803 00:46:43,671 --> 00:46:46,905 darkened, uh, after the cloud passed over. 804 00:46:46,905 --> 00:46:48,505 And the area that darkened 805 00:46:48,505 --> 00:46:52,505 is equivalent to about Utah and Arizona put together. 806 00:46:52,505 --> 00:46:54,538 So how did that happen? 807 00:46:54,538 --> 00:46:55,938 What is responsible for that? 808 00:46:55,938 --> 00:46:57,605 Well, we think the best explanation 809 00:46:57,605 --> 00:47:00,738 is a giant rainstorm. 810 00:47:00,738 --> 00:47:06,338 ♪ ♪ 811 00:47:06,338 --> 00:47:12,171 NARRATOR: In Titan's deserts, autumn brings change to the air. 812 00:47:12,171 --> 00:47:14,971 Monsoons arrive from the south... 813 00:47:19,238 --> 00:47:23,905 ...unleashing torrents of methane rain. 814 00:47:23,905 --> 00:47:28,738 But because of Titan's low gravity and dense atmosphere, 815 00:47:28,738 --> 00:47:32,838 the raindrops fall about six times slower than on Earth. 816 00:47:36,971 --> 00:47:40,871 These storms dump enough liquid methane onto the surface... 817 00:47:43,971 --> 00:47:46,305 ...to create flash floods... 818 00:47:49,605 --> 00:47:52,671 ...which drain into dry riverbeds... 819 00:47:56,971 --> 00:47:59,705 ...carving into the landscape... 820 00:48:09,971 --> 00:48:15,538 ...before spilling out onto vast floodplains. 821 00:48:20,905 --> 00:48:23,205 MACKENZIE: So, thanks to Cassini, we know 822 00:48:23,205 --> 00:48:25,405 that massive floods are happening on Titan. 823 00:48:25,405 --> 00:48:27,538 And just a few months later, 824 00:48:27,538 --> 00:48:31,105 which is only, like, five Titan days, that same land 825 00:48:31,105 --> 00:48:34,138 reverted to what it looked like before, it brightened. 826 00:48:34,138 --> 00:48:35,605 And the clouds themselves 827 00:48:35,605 --> 00:48:39,171 that were responsible for that rain had already moved on. 828 00:48:39,171 --> 00:48:44,905 ♪ ♪ 829 00:48:44,905 --> 00:48:50,605 NARRATOR: In 2022, five years after the Cassini mission ended, 830 00:48:50,605 --> 00:48:52,871 the James Webb Space Telescope 831 00:48:52,871 --> 00:48:58,605 turned its infrared gaze towards Saturn's largest moon. 832 00:48:59,638 --> 00:49:03,605 By now it was late summer in Titan's northern hemisphere, 833 00:49:03,605 --> 00:49:09,371 and the telescope spotted something remarkable: 834 00:49:09,371 --> 00:49:13,405 huge clouds over the north pole. 835 00:49:13,405 --> 00:49:18,805 The traveling storms had reached their destination. 836 00:49:19,838 --> 00:49:22,871 It is now believed Titan's storm belt 837 00:49:22,871 --> 00:49:28,005 goes on an epic 29-and-a-half-year journey 838 00:49:28,005 --> 00:49:33,138 from one pole to the other and back again. 839 00:49:33,138 --> 00:49:35,238 Slow-motion seasons 840 00:49:35,238 --> 00:49:39,771 unleashing massive, slow-motion storms, 841 00:49:39,771 --> 00:49:44,971 creating seasonal rivers of methane, 842 00:49:44,971 --> 00:49:49,571 in a desert on one of Saturn's moons. 843 00:49:49,571 --> 00:49:53,005 ♪ ♪ 844 00:49:58,505 --> 00:50:01,871 MACKENZIE: It's pretty incredible to be standing here 845 00:50:01,871 --> 00:50:04,805 in a desert landscape on the Earth 846 00:50:04,805 --> 00:50:07,438 and think about how similar that is 847 00:50:07,438 --> 00:50:09,871 to a landscape a billion miles away 848 00:50:09,871 --> 00:50:11,938 elsewhere in the solar system, 849 00:50:11,938 --> 00:50:15,505 the same processes, the same desert monsoon systems 850 00:50:15,505 --> 00:50:17,438 we think are at work on Titan, 851 00:50:17,438 --> 00:50:21,205 creating vistas much like this one that we see here. 852 00:50:21,205 --> 00:50:24,438 And yet the compounds, the materials 853 00:50:24,438 --> 00:50:27,571 that are involved in that process are totally different, 854 00:50:27,571 --> 00:50:29,571 and the temperature's totally different, 855 00:50:29,571 --> 00:50:31,471 and the timescales are totally different. 856 00:50:31,471 --> 00:50:34,505 And they're leading to a phenomenal landscape 857 00:50:34,505 --> 00:50:37,505 like the one that we see here. 858 00:50:37,505 --> 00:50:39,838 ♪ ♪ 859 00:50:46,205 --> 00:50:49,138 SOUSA-SILVA: On all these worlds, all this complexity, 860 00:50:49,138 --> 00:50:50,638 all these storms 861 00:50:50,638 --> 00:50:53,305 ultimately come from one fundamental law of nature. 862 00:50:53,305 --> 00:50:55,938 FLETCHER: That need to move energy 863 00:50:55,938 --> 00:50:58,671 from where it's plentiful to where it's scarce. 864 00:51:04,305 --> 00:51:06,571 DOTTIN: What makes these worlds so different 865 00:51:06,571 --> 00:51:08,305 are the unique conditions 866 00:51:08,305 --> 00:51:10,105 that are found in their atmospheres. 867 00:51:10,105 --> 00:51:12,038 (thunder rumbling) 868 00:51:12,038 --> 00:51:14,438 GUPTA: Because that determines the chemistry 869 00:51:14,438 --> 00:51:17,705 that drives their storms and shapes their surfaces. 870 00:51:17,705 --> 00:51:20,771 (thunder rumbling) 871 00:51:20,771 --> 00:51:23,071 GRINSPOON: You know, it's a pretty amazing time to be alive 872 00:51:23,071 --> 00:51:25,538 in, in that we have the ability 873 00:51:25,538 --> 00:51:29,038 to be monitoring weather on other planets. 874 00:51:29,038 --> 00:51:31,571 And yet I feel like we're in our early stages 875 00:51:31,571 --> 00:51:34,005 of understanding weather beyond Earth. 876 00:51:35,571 --> 00:51:37,538 DRANSFIELD: There are hundreds of billions of stars 877 00:51:37,538 --> 00:51:39,105 out there in the galaxy. 878 00:51:39,105 --> 00:51:41,905 And we now know that planets around stars is the norm. 879 00:51:43,305 --> 00:51:46,038 GAO: So that's potentially billions and billions 880 00:51:46,038 --> 00:51:47,705 of planets orbiting out there, 881 00:51:47,705 --> 00:51:49,438 all each with their own weather systems and storms. 882 00:51:50,638 --> 00:51:52,405 FRAEMAN: And I think there are things that are happening 883 00:51:52,405 --> 00:51:55,571 on these planets that we haven't even begun to imagine, 884 00:51:55,571 --> 00:51:57,305 because they're gonna be so different 885 00:51:57,305 --> 00:51:59,171 from anything else that we've been able 886 00:51:59,171 --> 00:52:02,271 to experience in our own solar system. 887 00:52:03,405 --> 00:52:05,505 GAO: And so that just makes me think of, 888 00:52:05,505 --> 00:52:07,705 what possibilities exist out there? 889 00:52:08,705 --> 00:52:12,405 What have we not thought of? 890 00:52:12,405 --> 00:52:16,538 ♪ ♪ 891 00:52:19,705 --> 00:52:23,938 ♪ ♪ 892 00:52:35,171 --> 00:52:38,038 ♪ ♪ 893 00:52:38,971 --> 00:52:46,505 ♪ ♪ 894 00:52:50,338 --> 00:52:57,871 ♪ ♪ 895 00:53:01,771 --> 00:53:09,305 ♪ ♪ 896 00:53:10,938 --> 00:53:18,471 ♪ ♪ 897 00:53:20,105 --> 00:53:27,638 ♪ ♪