1 00:00:05,367 --> 00:00:08,734 TYSON: We are a long way from home, and from our time. 2 00:00:09,200 --> 00:00:12,333 This was our Milky Way when the galaxy was young 3 00:00:12,467 --> 00:00:14,934 and more fertile than it is today. 4 00:00:15,066 --> 00:00:18,767 Back then, she birthed 30 times as many stars as she does now... 5 00:00:19,367 --> 00:00:22,567 a firestorm of star creation. 6 00:00:22,934 --> 00:00:26,033 It's a summer night, 11 billion years ago. 7 00:00:26,166 --> 00:00:28,367 We're on the planet of another star, 8 00:00:28,500 --> 00:00:31,333 one with an ideal view of the Milky Way galaxy's 9 00:00:31,467 --> 00:00:33,633 chaotic stellar nursery. 10 00:00:35,667 --> 00:00:39,133 Our own star was a child of the galaxy's later years, 11 00:00:39,967 --> 00:00:42,700 and that may be one of the reasons we exist. 12 00:00:42,834 --> 00:00:45,567 After the short-lived, more massive stars died out, 13 00:00:46,266 --> 00:00:47,467 there was time... 14 00:00:47,600 --> 00:00:51,867 another five billion years, for those dead stars to bequeath 15 00:00:52,000 --> 00:00:54,533 their heavier elements to us. 16 00:00:54,667 --> 00:00:57,767 These elements enriched and nurtured the formation 17 00:00:57,900 --> 00:00:59,834 of the planets and moons of our solar system. 18 00:01:01,233 --> 00:01:05,867 And we ourselves are made of that star stuff. 19 00:01:06,400 --> 00:01:10,367 Those blazing pink clouds of hydrogen gas are the swaddling 20 00:01:10,500 --> 00:01:13,400 of countless new-born stars. 21 00:01:13,834 --> 00:01:15,900 See those bright blue splashes? 22 00:01:16,033 --> 00:01:19,800 They're clusters of slightly older sibling stars. 23 00:01:21,834 --> 00:01:25,567 Gravity's embrace will transform this amorphous 24 00:01:25,700 --> 00:01:31,033 collection of gas and dust into the galaxy we call home today. 25 00:01:38,000 --> 00:01:39,800 (explosion) 26 00:01:49,266 --> 00:01:52,100 Our sun is born. 27 00:01:54,800 --> 00:01:57,033 The star endows her surrounding worlds 28 00:01:57,166 --> 00:02:01,000 with precious minerals, diamonds and green olivine... 29 00:02:01,133 --> 00:02:03,367 a mineral that will play a major role in our story. 30 00:02:06,400 --> 00:02:10,400 The stars make planets, moons and comets. 31 00:02:10,900 --> 00:02:15,066 There's Jupiter, the firstborn world of our solar system. 32 00:02:21,567 --> 00:02:24,800 These future planets and moons are awash with organic molecules... 33 00:02:25,834 --> 00:02:28,800 the chemical building blocks of life. 34 00:02:29,300 --> 00:02:32,934 This is their inheritance from the deaths of other stars. 35 00:02:37,800 --> 00:02:41,800 Does the cosmos give rise to life as naturally 36 00:02:41,934 --> 00:02:44,900 as it makes stars and worlds? 37 00:02:45,233 --> 00:02:48,767 This is our voyage to the heart of that mystery. 38 00:02:53,000 --> 00:02:58,800 (theme music plays) 39 00:03:18,367 --> 00:03:24,467 ♪ ♪ 40 00:03:45,333 --> 00:03:50,367 ♪ ♪ 41 00:04:08,533 --> 00:04:11,600 TYSON: Long, long ago, when our world was young, 42 00:04:11,734 --> 00:04:15,367 there was a city at the bottom of the sea that covered the Earth. 43 00:04:27,066 --> 00:04:29,900 It took tens of thousands of years to build this city, 44 00:04:31,633 --> 00:04:34,166 but there was no life on this world back then. 45 00:04:37,567 --> 00:04:40,333 So who built these submarine skyscrapers? 46 00:04:41,700 --> 00:04:43,433 Nature did. 47 00:04:43,567 --> 00:04:46,333 She made them with carbon dioxide and the same minerals 48 00:04:46,467 --> 00:04:49,367 she uses to make seashells and pearls... 49 00:04:49,934 --> 00:04:51,834 calcium carbonate. 50 00:04:51,967 --> 00:04:55,133 But these soaring towers were nothing compared to what 51 00:04:55,266 --> 00:04:57,433 happened beneath them. 52 00:04:57,867 --> 00:05:01,000 We'll need to get 1,000 times smaller to see it. 53 00:05:16,967 --> 00:05:19,633 Doesn't look like much, does it? 54 00:05:19,767 --> 00:05:21,900 But just wait. 55 00:05:22,200 --> 00:05:24,367 Our restless Mother Earth cracked open, 56 00:05:24,500 --> 00:05:27,100 and cold sea water poured down into her hot rocky mantle, 57 00:05:28,500 --> 00:05:31,066 getting richer in organic molecules and minerals, 58 00:05:31,200 --> 00:05:35,333 including a green jewel called olivine. 59 00:05:36,333 --> 00:05:40,400 This mix of water and minerals got so hot that it 60 00:05:40,533 --> 00:05:42,467 shot out of her with great force. 61 00:05:44,000 --> 00:05:46,834 The mixture became trapped in the pores of the carbonate 62 00:05:46,967 --> 00:05:49,900 rocks that would later become her towers. 63 00:05:51,200 --> 00:05:54,900 These pores were incubators, safe places where the organic 64 00:05:55,033 --> 00:05:57,667 molecules could become more concentrated. 65 00:05:58,834 --> 00:06:02,834 This is how we think that the rocks built life's first home. 66 00:06:03,367 --> 00:06:05,233 It was the beginning, at least in our little 67 00:06:05,367 --> 00:06:08,433 part of the cosmos, of an enduring collaboration 68 00:06:08,567 --> 00:06:10,467 between the minerals of earth, 69 00:06:10,600 --> 00:06:13,233 the rocks and life. 70 00:06:14,734 --> 00:06:17,400 See those snaky cracks? 71 00:06:17,767 --> 00:06:19,867 That's how this process got its name. 72 00:06:20,000 --> 00:06:21,734 Serpentinization. 73 00:06:22,133 --> 00:06:24,300 It's the evidence for the conversion of water and 74 00:06:24,433 --> 00:06:27,800 carbon dioxide into hydrogen and methane... 75 00:06:28,200 --> 00:06:31,867 the organic molecules that fueled this earthshaking event. 76 00:06:33,000 --> 00:06:35,367 Those scientists who search for life on other worlds, 77 00:06:35,500 --> 00:06:37,300 they used to say, "follow the water," 78 00:06:38,166 --> 00:06:41,133 because water is the most basic requirement for life. 79 00:06:41,567 --> 00:06:44,467 Now, they also say, "follow the rocks," 80 00:06:44,600 --> 00:06:47,567 because serpentinization is so closely associated with 81 00:06:47,700 --> 00:06:50,734 the processes that make life possible. 82 00:06:58,800 --> 00:07:02,233 To witness the main event, we have to get even smaller. 83 00:07:05,266 --> 00:07:08,467 At this scale, these caves look vast, 84 00:07:08,600 --> 00:07:11,600 but they're actually the tiny pores in the mortar of the towers. 85 00:07:13,000 --> 00:07:16,367 These jewels are the organic molecules which are, 86 00:07:16,500 --> 00:07:20,300 like everything, including you and me, made of atoms. 87 00:07:22,000 --> 00:07:25,200 In order to turn these inanimate jewels into jewelry, 88 00:07:25,333 --> 00:07:27,934 the stuff of life, it takes energy. 89 00:07:29,633 --> 00:07:33,100 We think it happened in a treasure cave like this one. 90 00:07:33,233 --> 00:07:35,834 The energy came from the reaction between the alkaline 91 00:07:35,967 --> 00:07:37,967 water trapped within the towers 92 00:07:38,467 --> 00:07:40,967 and the acidic water of the ocean. 93 00:07:41,100 --> 00:07:44,033 That ancient treasure chest filled with rings and 94 00:07:44,166 --> 00:07:46,000 bracelets and necklaces, 95 00:07:46,133 --> 00:07:47,967 longer and more complex molecules, 96 00:07:48,100 --> 00:07:51,133 until the greatest treasure of all... 97 00:07:51,633 --> 00:07:53,500 Life. 98 00:07:53,967 --> 00:07:55,934 We think it was that chemical reaction that provided 99 00:07:56,066 --> 00:07:58,900 the energy that powered the first cell. 100 00:07:59,400 --> 00:08:03,033 That was the spark that electrified the building blocks of life 101 00:08:03,166 --> 00:08:05,667 into something alive. 102 00:08:06,467 --> 00:08:08,767 Over time, the towers decayed, 103 00:08:09,200 --> 00:08:11,734 making it possible for the fledgling life within them 104 00:08:11,867 --> 00:08:14,467 to escape and evolve. 105 00:08:33,333 --> 00:08:39,266 ♪ ♪ 106 00:08:45,700 --> 00:08:48,533 What you've just seen is the most plausible scientific 107 00:08:48,667 --> 00:08:51,367 creation myth we have today for the origin of life. 108 00:08:52,367 --> 00:08:55,300 This hypothesis required the reunification 109 00:08:55,433 --> 00:08:58,400 of four long separated scientific fields: 110 00:08:58,900 --> 00:09:02,800 biology, chemistry, physics and geology. 111 00:09:07,233 --> 00:09:11,000 We think life first took hold in the rocks. 112 00:09:11,300 --> 00:09:13,800 And from day one, life was an escape artist, 113 00:09:13,934 --> 00:09:16,934 always wanting to break free, to conquer new worlds. 114 00:09:17,967 --> 00:09:21,066 Even the great big ocean couldn't contain it. 115 00:09:24,867 --> 00:09:27,967 If that's the true story of how life got started, 116 00:09:28,100 --> 00:09:31,700 it was long ago, back before the sky was blue, 117 00:09:31,834 --> 00:09:34,600 before the moon spun away from us to where it is today. 118 00:09:36,133 --> 00:09:38,600 Back when the planet was an ocean world, 119 00:09:38,734 --> 00:09:41,400 with waters bloodred with iron. 120 00:09:43,433 --> 00:09:46,734 Life would remake the world, the sea and the sky. 121 00:09:47,834 --> 00:09:51,133 But life doesn't always act in its own best interest. 122 00:09:51,266 --> 00:09:53,300 There came a day of reckoning, 123 00:09:53,433 --> 00:09:57,233 when life nearly destroyed itself. 124 00:10:01,834 --> 00:10:04,333 TYSON: The Cosmic Calendar is a way for us to wrap our 125 00:10:04,467 --> 00:10:06,367 heads around the vastness of time. 126 00:10:06,500 --> 00:10:08,367 To grasp the history of the cosmos, 127 00:10:08,500 --> 00:10:11,433 from the birth of our universe to this very moment, 128 00:10:12,166 --> 00:10:14,967 we've compressed all of it into a single calendar year. 129 00:10:15,734 --> 00:10:19,500 On this scale, every month represents about a billion years. 130 00:10:20,266 --> 00:10:24,100 Every day represents nearly 40 million years. 131 00:10:24,834 --> 00:10:30,233 That first day of the cosmic year began with the Big Bang, 132 00:10:30,934 --> 00:10:34,133 almost 14 billion years ago. 133 00:10:38,133 --> 00:10:40,834 Nothing really happened in our neck of the universe 134 00:10:40,967 --> 00:10:44,100 until about three billion years later... 135 00:10:44,233 --> 00:10:47,300 March 15 of the cosmic year, 136 00:10:47,633 --> 00:10:51,667 when our Milky Way galaxy began to form. 137 00:10:53,367 --> 00:10:59,667 Six billion years after that, our star, the Sun, was born. 138 00:11:01,200 --> 00:11:04,233 It was August 31st on the Cosmic Calendar. 139 00:11:07,934 --> 00:11:10,233 Jupiter and the other planets, including our own, 140 00:11:10,367 --> 00:11:12,734 would soon follow. 141 00:11:19,000 --> 00:11:22,667 This was our planet nearly four billion years ago... 142 00:11:23,633 --> 00:11:26,900 September 21st on the Cosmic Calendar, 143 00:11:27,033 --> 00:11:29,266 when we believe life began. 144 00:11:29,400 --> 00:11:32,000 The atmosphere was a hydrocarbon smog. 145 00:11:33,533 --> 00:11:37,033 No oxygen to breathe and no one to breathe it. 146 00:11:40,033 --> 00:11:43,500 We've only recently begun to appreciate how powerfully 147 00:11:43,633 --> 00:11:46,166 life has shaped the planet. 148 00:11:46,300 --> 00:11:48,734 When we think about the ways life has changed Earth, 149 00:11:48,867 --> 00:11:52,233 the first things that come to mind are the green expanses 150 00:11:52,367 --> 00:11:55,166 of forests, and the sprawling cities. 151 00:11:55,300 --> 00:11:59,266 But life began transforming the planet long before there 152 00:11:59,400 --> 00:12:01,467 were any such things. 153 00:12:03,600 --> 00:12:07,367 A billion years after that tiny glimmer at the bottom of the sea, 154 00:12:08,767 --> 00:12:11,767 life had become a global phenomenon thanks to 155 00:12:11,900 --> 00:12:15,433 a champion that to this day has never been vanquished. 156 00:12:16,400 --> 00:12:20,233 I give you the cyanobacteria. 157 00:12:27,967 --> 00:12:31,500 In business for 2.7 billion years, 158 00:12:31,633 --> 00:12:35,000 cyanobacteria can make a living anywhere. 159 00:12:35,900 --> 00:12:38,667 Fresh water, salt water, hot springs, salt mines... 160 00:12:39,967 --> 00:12:43,533 makes no difference, it's all home to them. 161 00:12:46,000 --> 00:12:50,233 Over the next 400 million years, the cyanobacteria... 162 00:12:50,367 --> 00:12:54,066 taking in carbon dioxide and giving back oxygen, 163 00:12:54,200 --> 00:12:58,600 turned the sky blue. 164 00:13:00,367 --> 00:13:04,633 But the cyanobacteria didn't just change the sky, 165 00:13:05,300 --> 00:13:08,000 they reached into the very rocks themselves 166 00:13:08,133 --> 00:13:10,767 and changed them, too. 167 00:13:10,900 --> 00:13:13,400 Oxygen rusted the iron, 168 00:13:13,533 --> 00:13:16,400 working its magic on the minerals. 169 00:13:18,000 --> 00:13:21,133 Of the 5,000 kinds of minerals on Earth, 170 00:13:21,266 --> 00:13:26,233 3,500 of them arose as a result of the oxygen made by life. 171 00:13:28,266 --> 00:13:31,533 But here comes that day of reckoning. 172 00:13:50,333 --> 00:13:54,333 Cyanobacteria were the dominant life-form on this planet, 173 00:13:54,467 --> 00:13:57,000 wreaking havoc wherever they went, 174 00:13:57,133 --> 00:13:59,667 changing the landscape, the water and the skies. 175 00:14:01,000 --> 00:14:04,433 This was 2.3 billion years ago, 176 00:14:04,900 --> 00:14:08,066 or late October on the Cosmic Calendar. 177 00:14:09,433 --> 00:14:13,233 But the cyanobacteria shared the planet with other beings: 178 00:14:13,567 --> 00:14:16,967 The anaerobes, life-forms that had come of age before 179 00:14:17,100 --> 00:14:20,233 cyanobacteria had begun to pollute the Earth with oxygen. 180 00:14:21,700 --> 00:14:24,867 For the anaerobes, oxygen was poison, 181 00:14:25,233 --> 00:14:27,467 but the cyanobacteria wouldn't stop loading up 182 00:14:27,600 --> 00:14:30,233 the atmosphere with the stuff. 183 00:14:30,567 --> 00:14:32,700 For the anaerobes, and nearly all of the other 184 00:14:32,834 --> 00:14:36,700 life on Earth, it was an oxygen apocalypse. 185 00:14:37,033 --> 00:14:39,600 The lone survivors among the anaerobes were those 186 00:14:39,734 --> 00:14:42,100 who sought refuge at the bottom of the sea, 187 00:14:42,233 --> 00:14:45,166 deep in the sediment where the oxygen could not reach them. 188 00:14:51,667 --> 00:14:56,800 The cyanobacteria acted like oxygen-pumping machines. 189 00:14:57,033 --> 00:15:00,867 They continued in overdrive, and 400 million years later, 190 00:15:01,000 --> 00:15:04,700 they brought about an even more radical change to the planet. 191 00:15:05,166 --> 00:15:08,667 Remember those serpentinized rocks at the bottom of the sea 192 00:15:08,800 --> 00:15:11,333 that were cranking out hydrogen and methane? 193 00:15:11,967 --> 00:15:14,367 Methane is a powerful greenhouse gas, 194 00:15:14,500 --> 00:15:17,867 and back then it was the main thing keeping the planet warm. 195 00:15:18,934 --> 00:15:23,066 But once again, the oxygen produced by life shook things up. 196 00:15:23,433 --> 00:15:26,867 It gobbled up the methane, producing carbon dioxide, 197 00:15:27,000 --> 00:15:29,300 a much less potent greenhouse gas... 198 00:15:29,433 --> 00:15:31,800 meaning it was not as efficient at trapping heat 199 00:15:31,934 --> 00:15:34,133 in Earth's atmosphere. 200 00:15:34,266 --> 00:15:37,300 Earth's temperature began to plunge. 201 00:15:43,633 --> 00:15:48,533 Life, the escape artist, busted out of the icy death grip 202 00:15:48,667 --> 00:15:50,834 that entombed the planet. 203 00:15:50,967 --> 00:15:54,233 The corpses of dead bacteria left behind a planetwide 204 00:15:54,367 --> 00:15:56,834 reservoir of carbon dioxide. 205 00:15:57,700 --> 00:16:01,667 Volcanoes pumped the carbon dioxide in huge quantities into the atmosphere, 206 00:16:03,000 --> 00:16:05,934 warming the planet and melting the ice. 207 00:16:06,066 --> 00:16:07,900 Over the next billion years, 208 00:16:08,033 --> 00:16:10,867 life and the rocks continued their elaborate dance, 209 00:16:11,000 --> 00:16:14,166 taking the planet through freezes and thaws. 210 00:16:14,300 --> 00:16:18,533 Then, 540 million years ago, something wondrous happened. 211 00:16:22,066 --> 00:16:25,934 Life, which had been all about microbes and simple 212 00:16:26,066 --> 00:16:30,200 multicellular creatures, suddenly took off in what's 213 00:16:30,333 --> 00:16:32,467 called the Cambrian Explosion. 214 00:16:33,734 --> 00:16:37,133 Life grew legs, eyes, gills, teeth, 215 00:16:38,633 --> 00:16:42,767 and rapidly began to evolve the forms of its stunning diversity. 216 00:16:44,166 --> 00:16:47,500 We don't yet know what it was that allowed life to diversify 217 00:16:47,633 --> 00:16:50,800 so dramatically, but we have some plausible theories. 218 00:16:52,133 --> 00:16:54,000 It could have been all those calcium minerals in 219 00:16:54,133 --> 00:16:56,567 the seawater that came from the volcanoes. 220 00:16:56,700 --> 00:16:59,333 Life had grown a backbone and put on a shell. 221 00:17:00,433 --> 00:17:03,100 It had found a way to collaborate with the rocks 222 00:17:03,233 --> 00:17:05,200 to make its own armor. 223 00:17:05,333 --> 00:17:09,600 Now life could grow larger and venture forth into new territories. 224 00:17:12,166 --> 00:17:14,800 Or maybe it was the protection afforded by the 225 00:17:14,934 --> 00:17:17,834 canopy built by the cyanobacteria. 226 00:17:18,700 --> 00:17:21,867 The oxygenation of the atmosphere created the ozone layer. 227 00:17:23,567 --> 00:17:26,734 This made it possible for life to break out of the 228 00:17:26,867 --> 00:17:30,500 safety of the oceans and inhabit the land without 229 00:17:30,633 --> 00:17:34,433 being assaulted by the sun's deadly ultraviolet rays. 230 00:17:35,767 --> 00:17:40,166 For billions of years, all life could do was ooze. 231 00:17:41,033 --> 00:17:46,500 Now, life began to swim, run, jump and fly. 232 00:17:48,400 --> 00:17:52,367 Life, the escape artist, had gotten so good at wriggling 233 00:17:52,500 --> 00:17:56,800 out of every confine, no prison on Earth could hold it. 234 00:17:58,467 --> 00:18:00,233 And there will come a day, 235 00:18:00,367 --> 00:18:03,500 when life would even escape from Earth. 236 00:18:05,166 --> 00:18:08,166 Life will not be contained. 237 00:18:15,166 --> 00:18:20,800 ♪ ♪ 238 00:18:26,367 --> 00:18:29,066 Retracing life's odyssey back to the very beginning 239 00:18:29,200 --> 00:18:31,100 required a new kind of science, 240 00:18:31,834 --> 00:18:34,200 one that reunited the disciplines. 241 00:18:34,333 --> 00:18:36,867 The man who founded this new approach also happened 242 00:18:37,000 --> 00:18:39,500 to be an escape artist himself. 243 00:18:39,633 --> 00:18:42,266 He fled history's most implacable killers, 244 00:18:42,400 --> 00:18:46,133 right here in this forest, jesting at his tormentors 245 00:18:46,266 --> 00:18:49,700 every step of the way. 246 00:18:57,266 --> 00:18:58,834 TYSON: Remember this place? 247 00:18:58,967 --> 00:19:01,000 It's London's Royal Institution, 248 00:19:01,133 --> 00:19:03,500 where Michael Faraday spent his life. 249 00:19:04,000 --> 00:19:07,100 Back in his time, in the first half of the 19th century, 250 00:19:07,800 --> 00:19:10,533 the intimate relationship between life and the rocks 251 00:19:10,667 --> 00:19:13,000 had yet to be discovered. 252 00:19:14,200 --> 00:19:17,133 Before science could tackle the origin of life, 253 00:19:17,266 --> 00:19:18,734 it had to change. 254 00:19:18,867 --> 00:19:21,333 This development was foretold by a scientist 255 00:19:21,467 --> 00:19:25,433 whose gifts to the world, were decidedly mixed. 256 00:19:26,467 --> 00:19:30,233 Christian Friedrich Schönbein was a German-Swiss chemist who 257 00:19:30,367 --> 00:19:34,133 was conducting an experiment on using electricity to reduce 258 00:19:34,266 --> 00:19:36,500 water into its two chemical constituents, 259 00:19:37,300 --> 00:19:40,000 oxygen and hydrogen. 260 00:19:40,333 --> 00:19:42,667 Schönbein thought he smelled something familiar, 261 00:19:42,800 --> 00:19:45,333 something like the air after a thunderstorm. 262 00:19:46,166 --> 00:19:48,767 Schönbein had discovered ozone. 263 00:19:49,333 --> 00:19:51,667 Remember, that's the layer in the atmosphere that made 264 00:19:51,800 --> 00:19:54,834 it possible for our distant ancestors to leave the water 265 00:19:54,967 --> 00:19:57,467 for the land, and it still protects us from 266 00:19:57,600 --> 00:19:59,934 ultraviolet rays to this day. 267 00:20:01,600 --> 00:20:04,133 Schönbein loved to experiment. 268 00:20:04,266 --> 00:20:07,000 So much so that his wife famously exacted a promise 269 00:20:07,133 --> 00:20:10,567 from him not to use their kitchen as his laboratory. 270 00:20:29,333 --> 00:20:33,500 ♪ ♪ 271 00:20:34,333 --> 00:20:35,934 SCHÖNBEIN: Oh. 272 00:20:36,800 --> 00:20:40,000 TYSON: Schönbein had just invented a new weapon of mass destruction. 273 00:20:47,867 --> 00:20:50,767 A chemical explosive more powerful than gunpowder. 274 00:20:52,066 --> 00:20:55,533 Upon further refinement, gun cotton would industrialize 275 00:20:55,667 --> 00:20:58,600 warfare on a horrendous scale. 276 00:21:00,066 --> 00:21:02,934 But it was also Schönbein who had a prophetic vision of 277 00:21:03,066 --> 00:21:05,000 a new field of science. 278 00:21:05,133 --> 00:21:07,100 He wrote in 1838: 279 00:21:07,233 --> 00:21:09,667 "Before the mystery of the genesis of our planets 280 00:21:09,800 --> 00:21:12,033 and their inorganic matter can be revealed, 281 00:21:12,600 --> 00:21:16,400 a comparative science of geochemistry must be launched." 282 00:21:18,033 --> 00:21:20,233 50 years later, the man who would realize 283 00:21:20,367 --> 00:21:22,800 Schönbein's dream was born. 284 00:21:23,734 --> 00:21:26,133 He was another German-Swiss. 285 00:21:26,266 --> 00:21:29,066 Victor Goldschmidt was so brilliant, 286 00:21:29,200 --> 00:21:32,567 he was offered a position here at the University of Oslo 287 00:21:32,700 --> 00:21:35,967 without ever taking a test or earning a degree. 288 00:21:36,500 --> 00:21:39,934 That was in 1909, when he was only 21. 289 00:21:40,667 --> 00:21:44,633 Three years later, he was awarded Norway's greatest scientific prize. 290 00:21:48,200 --> 00:21:52,333 Victor Goldschmidt saw the Earth as a single system. 291 00:21:52,467 --> 00:21:55,000 He knew that in order to get the whole picture, 292 00:21:55,133 --> 00:21:58,767 you couldn't just know physics, chemistry, or geology... 293 00:21:59,100 --> 00:22:01,433 you had to know them all. 294 00:22:02,266 --> 00:22:05,066 This was in the early days of the study of the basic elements. 295 00:22:06,333 --> 00:22:09,133 Goldschmidt applied this new knowledge to create his own 296 00:22:09,266 --> 00:22:11,033 version of the periodic table, 297 00:22:11,734 --> 00:22:14,100 one that is still in use today. 298 00:22:14,533 --> 00:22:16,967 It illuminated how crystals and complex minerals could 299 00:22:17,100 --> 00:22:19,600 be formed from more basic elements. 300 00:22:19,734 --> 00:22:22,100 Goldschmidt was discovering how matter evolves 301 00:22:22,233 --> 00:22:26,467 into mountains and cliffs and canyons. 302 00:22:30,834 --> 00:22:34,100 In 1928, he made a fateful decision to accept 303 00:22:34,233 --> 00:22:36,333 an appointment at the University of Göttingen, 304 00:22:36,467 --> 00:22:40,133 in Germany, where an institute had been built just for him. 305 00:22:40,500 --> 00:22:44,533 His colleagues thought these were his happiest years, until... 306 00:22:44,667 --> 00:22:47,433 (hammering) 307 00:22:50,333 --> 00:22:53,033 1933, 308 00:22:55,900 --> 00:22:58,433 when Adolf Hitler came to power. 309 00:22:59,033 --> 00:23:01,934 Goldschmidt was Jewish, but not observant. 310 00:23:02,066 --> 00:23:04,400 Hitler changed all that for him. 311 00:23:04,533 --> 00:23:07,166 He now began to publicly identify himself with the 312 00:23:07,300 --> 00:23:09,200 local Jewish community. 313 00:23:09,333 --> 00:23:12,200 Hitler made it compulsory for everyone to list any 314 00:23:12,333 --> 00:23:15,700 Jewish forbearers going back several generations. 315 00:23:16,233 --> 00:23:18,900 There were those who tried to conceal a grandfather who 316 00:23:19,033 --> 00:23:21,400 might land them in a concentration camp. 317 00:23:21,533 --> 00:23:24,433 But Goldschmidt proudly declared on his forms that all 318 00:23:24,567 --> 00:23:26,967 of his ancestors were Jewish. 319 00:23:27,100 --> 00:23:30,567 Hitler and Hermann Göring, founder of the Gestapo, 320 00:23:30,700 --> 00:23:32,500 were not amused. 321 00:23:36,400 --> 00:23:37,600 GOLDSCHMIDT: Hmm? 322 00:23:37,734 --> 00:23:39,367 TYSON: They personally sent a letter to Goldschmidt telling 323 00:23:39,500 --> 00:23:42,367 him he was summarily dismissed from his university position. 324 00:23:48,266 --> 00:23:51,233 He fled to Norway with only the clothes on his back. 325 00:23:58,066 --> 00:24:00,767 Goldschmidt concentrated his research on olivine, 326 00:24:01,233 --> 00:24:03,266 that green jewel of a mineral left over from 327 00:24:03,400 --> 00:24:05,533 the formation of the solar system. 328 00:24:06,100 --> 00:24:08,567 He was fascinated by its power to withstand even 329 00:24:08,700 --> 00:24:11,200 the highest temperatures. 330 00:24:11,734 --> 00:24:14,400 He was the first to speculate that olivine may have played 331 00:24:14,533 --> 00:24:17,900 a role in setting the stage for the origin of life. 332 00:24:18,467 --> 00:24:20,800 At the same time, he wondered about the presence 333 00:24:20,934 --> 00:24:23,300 of olivine throughout the cosmos. 334 00:24:24,200 --> 00:24:27,633 This was the beginning of a field called cosmochemistry. 335 00:24:29,400 --> 00:24:32,934 In 1940, when the Germans invaded Norway, 336 00:24:33,066 --> 00:24:36,734 Goldschmidt took to carrying a cyanide capsule in his pocket 337 00:24:36,867 --> 00:24:38,900 so that he could kill himself instantly if the 338 00:24:39,033 --> 00:24:41,400 Gestapo came for him. 339 00:24:41,734 --> 00:24:44,500 When a fellow scientist asked if he could get one, too, 340 00:24:44,633 --> 00:24:46,533 Goldschmidt answered: 341 00:24:46,667 --> 00:24:50,066 "This poison is for chemistry professors only. 342 00:24:50,200 --> 00:24:53,900 You, as a physicist, will have to use a rope." 343 00:24:59,800 --> 00:25:01,166 (knock) 344 00:25:01,300 --> 00:25:02,567 NAZI: Herr Goldschmidt. 345 00:25:02,700 --> 00:25:04,100 TYSON: But when the Germans arrived, 346 00:25:04,233 --> 00:25:06,467 Goldschmidt kept the cyanide in his pocket. 347 00:25:07,800 --> 00:25:09,033 NAZI: Goldschmidt. 348 00:25:09,166 --> 00:25:11,600 (speaking in German) 349 00:25:14,100 --> 00:25:16,633 TYSON: He was sent to the Berg concentration camp before 350 00:25:16,767 --> 00:25:19,233 they were ready to deport him to Auschwitz, 351 00:25:19,767 --> 00:25:23,500 a place he told friends that "had not been highly recommended." 352 00:25:29,967 --> 00:25:31,834 Goldschmidt was too important a scientist 353 00:25:31,967 --> 00:25:34,700 for the Nazis to exterminate. 354 00:25:34,834 --> 00:25:37,500 He was given the chance of survival if he would put 355 00:25:37,633 --> 00:25:39,934 his science in the service of the Reich. 356 00:25:41,033 --> 00:25:44,433 But Goldschmidt dared to toy with his captors. 357 00:25:44,834 --> 00:25:48,533 He would lead the Germans on a scientific wild goose chase. 358 00:25:48,667 --> 00:25:52,133 He sent them searching for nonexistent minerals 359 00:25:52,266 --> 00:25:54,667 and deceived them into believing these were resources 360 00:25:55,200 --> 00:25:57,834 that would be critical to the war effort. 361 00:25:58,567 --> 00:26:01,633 His ruse could have been discovered at any moment, 362 00:26:01,767 --> 00:26:03,800 and that would have meant certain death in the most 363 00:26:03,934 --> 00:26:06,467 fiendish way possible. 364 00:26:07,734 --> 00:26:11,200 By the end of 1942, the Norwegian Resistance knew 365 00:26:11,333 --> 00:26:13,734 that Goldschmidt was in the gravest danger. 366 00:26:14,567 --> 00:26:17,367 They arranged for him to escape across the Swedish frontier. 367 00:26:26,266 --> 00:26:28,967 Goldschmidt spent the rest of the war in Sweden, 368 00:26:29,100 --> 00:26:33,066 and then England, contributing his knowledge to the Allies. 369 00:26:33,433 --> 00:26:34,967 Always in frail health, 370 00:26:35,100 --> 00:26:38,233 he never recovered from the hardships of the war. 371 00:26:38,367 --> 00:26:42,567 Victor Goldschmidt died a year and a half after it was over. 372 00:26:43,066 --> 00:26:45,467 But during that period, he wrote a research paper on 373 00:26:45,600 --> 00:26:48,400 the complex organic molecules that he thought might 374 00:26:48,533 --> 00:26:51,300 have led to the origin of life on Earth. 375 00:26:51,433 --> 00:26:54,166 And the ideas in that paper remain central in our 376 00:26:54,300 --> 00:26:57,300 effort to understand how life came to be. 377 00:27:02,266 --> 00:27:06,467 Goldschmidt never knew that the generations of geochemists 378 00:27:06,600 --> 00:27:10,300 who came after him would consider him their founder. 379 00:27:12,433 --> 00:27:15,800 Among his last wishes was a simple request. 380 00:27:16,767 --> 00:27:18,834 He wanted to be cremated and 381 00:27:18,967 --> 00:27:22,133 to have his ashes encased in an urn... 382 00:27:22,667 --> 00:27:26,467 made of the thing he believed to be the stuff of life, 383 00:27:27,567 --> 00:27:30,600 his beloved olivine. 384 00:27:31,533 --> 00:27:34,433 The universe makes galaxies. 385 00:27:34,567 --> 00:27:37,200 Galaxies make stars. 386 00:27:37,333 --> 00:27:40,467 Stars make worlds. 387 00:27:40,967 --> 00:27:44,767 Are there other Lost Cities of Life in the cosmos? 388 00:27:45,467 --> 00:27:54,934 Come with me. 389 00:27:55,066 --> 00:27:58,133 TYSON: There are dues to be paid for cosmic citizenship. 390 00:27:58,600 --> 00:28:01,166 As a spacefaring species, you have to worry about 391 00:28:01,300 --> 00:28:04,567 contaminating the worlds you visit and about bringing 392 00:28:04,700 --> 00:28:08,567 back alien stowaways that might pose a danger to your home world. 393 00:28:09,734 --> 00:28:13,333 There are protocols for planetary protection. 394 00:28:13,767 --> 00:28:17,700 NASA designates five categories of worlds in the cosmos. 395 00:28:19,166 --> 00:28:22,400 Earth's moon, for instance, is a Category-1 world... 396 00:28:23,300 --> 00:28:26,967 a place so lifeless, we pose no threat to it, 397 00:28:27,100 --> 00:28:30,567 and it poses no threat to us. 398 00:28:31,266 --> 00:28:35,900 The riskiest of all is a Restricted Category-5 world, 399 00:28:36,033 --> 00:28:38,667 like this one, Mars. 400 00:28:39,100 --> 00:28:41,300 The conditions for indigenous life... 401 00:28:41,433 --> 00:28:45,133 in the past, or even now, hidden in some subsurface recess, 402 00:28:45,900 --> 00:28:48,000 are not beyond possible. 403 00:28:48,133 --> 00:28:50,133 We have to be very careful, 404 00:28:50,266 --> 00:28:54,433 for our own sake and for the life that could conceivably be there. 405 00:28:55,667 --> 00:28:58,934 The Restricted Cat-5 designation is a recognition 406 00:28:59,066 --> 00:29:01,200 of life's genius for escape. 407 00:29:01,333 --> 00:29:04,533 It applies to sample return missions from those worlds 408 00:29:04,667 --> 00:29:07,133 where life may have gotten started... 409 00:29:07,633 --> 00:29:11,600 those worlds that may have, or once may have had, 410 00:29:11,734 --> 00:29:15,433 Lost Cities of Life lying at the bottom of their seas. 411 00:29:16,300 --> 00:29:19,567 But in a sense, our robot emissaries themselves... 412 00:29:19,700 --> 00:29:21,767 our landers, rovers and orbiters, 413 00:29:21,900 --> 00:29:25,100 are a manifestation of life's relentless imperative 414 00:29:25,233 --> 00:29:29,100 to seek out and take new territory, and this means that some of 415 00:29:29,233 --> 00:29:33,000 our emissaries have to be destroyed as soon as their missions are over. 416 00:29:34,700 --> 00:29:37,066 Like, poor Juno. 417 00:29:37,600 --> 00:29:39,867 After a multiyear reconnaissance of Jupiter, 418 00:29:40,000 --> 00:29:42,700 NASA is sending her to her death. 419 00:29:43,033 --> 00:29:45,166 Not because they were worried about Jupiter. 420 00:29:45,300 --> 00:29:47,934 There's hardly any chance that one of our spacecraft 421 00:29:48,066 --> 00:29:51,633 could compromise future investigations of the giant gas planet. 422 00:29:52,400 --> 00:29:55,667 Any rogue microbe would catch a downdraft and sink where 423 00:29:55,800 --> 00:29:58,633 it would be broiled by the scathing temperatures. 424 00:29:59,066 --> 00:30:02,233 That's why Jupiter's only a Category-2 world. 425 00:30:02,367 --> 00:30:05,667 But one of Jupiter's moons is a Restricted Cat-5, 426 00:30:06,266 --> 00:30:08,900 and NASA can't take the chance that Juno might 427 00:30:09,033 --> 00:30:11,200 inadvertently crash into it. 428 00:30:12,467 --> 00:30:15,900 Europa is another one of only three Restricted Cat-5 worlds 429 00:30:16,033 --> 00:30:18,767 in the solar system, and one of Jupiter's 80 430 00:30:18,900 --> 00:30:21,633 and still counting, moons. 431 00:30:33,567 --> 00:30:36,500 Michael Faraday discovered Earth's magnetic field, 432 00:30:36,633 --> 00:30:38,767 and there's one around Jupiter, too. 433 00:30:38,900 --> 00:30:41,166 We can see it if we switch from looking at Jupiter in 434 00:30:41,300 --> 00:30:44,033 visible light to looking at it in radio waves. 435 00:30:45,900 --> 00:30:50,633 Jupiter's magnetic field is much stronger and 18,000 times bigger. 436 00:30:51,300 --> 00:30:54,834 It's a gigantic trap for charged particles that are the solar wind. 437 00:30:55,500 --> 00:30:58,300 That's one of the things that lights up the aurora, 438 00:30:58,433 --> 00:31:00,900 the northern and southern Lights on Jupiter, 439 00:31:01,200 --> 00:31:04,166 and it does the same thing on Earth. 440 00:31:08,900 --> 00:31:11,600 Imagine what it's like for little Europa and her sister 441 00:31:11,734 --> 00:31:15,100 moons to live so close to the king of the Planets. 442 00:31:15,867 --> 00:31:18,767 Massive Jupiter holds Europa to him in a gravitational 443 00:31:18,900 --> 00:31:22,467 embrace so powerful that in four billion years, 444 00:31:22,600 --> 00:31:25,834 she has never been able to turn her face away from his. 445 00:31:27,567 --> 00:31:30,533 Jupiter's hold on her is so fierce that it tears her skin apart. 446 00:31:32,133 --> 00:31:34,633 See those broad scars? 447 00:31:34,767 --> 00:31:36,433 Watch them closely and listen. 448 00:31:36,700 --> 00:31:39,233 (colliding rocks) 449 00:31:40,100 --> 00:31:44,200 That's the sound of a world being gravitationally tormented. 450 00:31:44,333 --> 00:31:48,200 It's called tidal flexing, and it's not just Jupiter, 451 00:31:48,967 --> 00:31:51,767 her sister moons pull on her, too. 452 00:31:52,367 --> 00:31:55,767 We are half a billion miles from the sun's warmth, 453 00:31:55,900 --> 00:31:58,667 five times farther away than Earth is, 454 00:31:58,800 --> 00:32:02,166 but this tidal flexing keeps Europa toasty inside. 455 00:32:03,700 --> 00:32:06,433 Beneath her chaotic surface, there's an ocean ten times 456 00:32:06,567 --> 00:32:09,900 deeper than the deepest seas on Earth. 457 00:32:25,066 --> 00:32:28,233 ♪ ♪ 458 00:32:28,367 --> 00:32:32,867 We're on our way to another Restricted Cat-5 world. 459 00:32:33,000 --> 00:32:34,333 No, not Saturn. 460 00:32:34,467 --> 00:32:36,767 Saturn's another Cat-2. 461 00:32:38,033 --> 00:32:41,934 Any life passing through those cloud belts wouldn't have a chance. 462 00:32:42,433 --> 00:32:44,734 They're made mostly of ammonia. 463 00:32:44,867 --> 00:32:47,400 Below them are bands of water vapor. 464 00:32:47,533 --> 00:32:52,333 In one of our future voyages, we'll go there at a terrible cost. 465 00:32:54,266 --> 00:32:55,834 It's not Titan, either. 466 00:32:55,967 --> 00:32:58,467 Titan's another Category-2 world. 467 00:32:58,600 --> 00:33:01,266 Just as with Saturn, the possibility of us interfering 468 00:33:01,400 --> 00:33:04,900 with the life that might be there is too remote. 469 00:33:05,233 --> 00:33:07,266 Of course, there's always the chance that Titan life 470 00:33:07,400 --> 00:33:10,066 is stranger than our ability to imagine. 471 00:33:10,200 --> 00:33:12,667 Even if that's the case, there is little likelihood 472 00:33:12,800 --> 00:33:15,667 that any form of Earth life could harm it. 473 00:33:19,333 --> 00:33:23,533 There she is, our Restricted Cat-5 world. 474 00:33:34,400 --> 00:33:37,667 TYSON: There's a world in our solar system that may harbor life. 475 00:33:39,567 --> 00:33:42,400 You're looking at two of the first people ever to see it. 476 00:33:43,433 --> 00:33:46,100 William Herschel saw farther into the deep waters 477 00:33:46,233 --> 00:33:48,633 of the cosmic ocean than anyone before him. 478 00:33:49,734 --> 00:33:52,800 His son, John, would also become a distinguished astronomer. 479 00:33:54,000 --> 00:33:57,967 But tonight is back when John was a child in the summer of 1802. 480 00:33:59,400 --> 00:34:02,367 That's when we first met them on an earlier voyage. 481 00:34:03,500 --> 00:34:05,633 WILLIAM: John, I want to show you something. 482 00:34:06,367 --> 00:34:08,467 Come with me. 483 00:34:13,300 --> 00:34:16,100 TYSON: This was then the largest telescope on Earth 484 00:34:16,233 --> 00:34:18,066 and would be for 50 years. 485 00:34:21,900 --> 00:34:24,834 CAROLINE: Well, what have we here? Hmm? 486 00:34:24,967 --> 00:34:28,000 Isn't it awfully late for a little boy to be up? 487 00:34:28,600 --> 00:34:31,633 JOHN: Father has promised to show me something, Aunt Caroline. 488 00:34:31,767 --> 00:34:33,834 TYSON: William's sister, Caroline Herschel, 489 00:34:33,967 --> 00:34:37,266 was a world-renowned astronomer in her own right. 490 00:34:37,400 --> 00:34:40,800 She was the first woman anywhere on Earth to be paid 491 00:34:40,934 --> 00:34:43,066 for being a scientist. 492 00:34:45,100 --> 00:34:47,200 She was just four-foot-three. 493 00:34:47,333 --> 00:34:48,934 When Caroline was ten years old, 494 00:34:49,066 --> 00:34:50,834 she was stricken with typhus. 495 00:34:50,967 --> 00:34:54,533 She lost part of the vision in her left eye and stopped growing. 496 00:34:54,900 --> 00:34:59,033 And yet, she defied the limitations of her time to a point. 497 00:35:01,567 --> 00:35:03,567 Caroline had just published her work in the 498 00:35:03,700 --> 00:35:06,667 "Catalogue of Nebulae and Clusters of Stars," 499 00:35:07,166 --> 00:35:09,967 but it was under her brother William's name. 500 00:35:10,700 --> 00:35:13,734 It was 1802, after all. 501 00:35:14,133 --> 00:35:16,700 Her nephew, John, would grow up to build on her 502 00:35:16,834 --> 00:35:19,834 work and create the "New General Catalogue." 503 00:35:21,000 --> 00:35:26,400 Many astronomical bodies are still designated by their NGC number today. 504 00:35:30,767 --> 00:35:35,133 WILLIAM: A few more degrees east and a degree north. 505 00:35:35,567 --> 00:35:36,934 ASSISTANT: Yes, sir. 506 00:35:42,166 --> 00:35:46,367 WILLIAM: Stop, stop! There she is. 507 00:35:49,500 --> 00:35:52,467 JOHN: Father! I've never seen that before. 508 00:35:53,066 --> 00:35:54,767 Is it a new star? 509 00:35:54,900 --> 00:35:58,700 WILLIAM: No, son, it's a new moon. 510 00:35:58,967 --> 00:36:01,066 I call it Saturn Two. 511 00:36:01,200 --> 00:36:05,000 JOHN: Oh, but Father, we must think of a better name than that. 512 00:36:05,800 --> 00:36:08,400 WILLIAM: That's your job, my boy. 513 00:36:08,533 --> 00:36:11,300 TYSON: And John would do exactly as his father asked. 514 00:36:11,433 --> 00:36:15,033 He named the moon Enceladus, after the Giant in Greek 515 00:36:15,166 --> 00:36:18,166 mythology who was the son of the Earth and the Sky. 516 00:36:19,467 --> 00:36:22,600 Enceladus fought the goddess Athena in an epic struggle 517 00:36:22,734 --> 00:36:24,533 for control of the universe. 518 00:36:34,133 --> 00:36:36,467 You don't have to be an astrobiologist to know at 519 00:36:36,600 --> 00:36:39,600 first glance that life is everywhere on Earth. 520 00:36:41,266 --> 00:36:45,233 It's changed virtually every square inch of the place. 521 00:36:45,600 --> 00:36:47,934 From an alien point of view, Earth would certainly have a 522 00:36:48,066 --> 00:36:51,100 Restricted Cat-5 status. 523 00:36:52,467 --> 00:36:55,600 But Enceladus keeps its secrets hidden deep inside. 524 00:37:10,100 --> 00:37:14,767 ♪ ♪ 525 00:37:21,834 --> 00:37:25,300 Those geysers of ice and water vapor are shooting out 526 00:37:25,433 --> 00:37:28,567 of Enceladus at 800 miles per hour. 527 00:37:29,166 --> 00:37:32,667 They're this moon's contribution to the outermost so-called "E" ring of Saturn. 528 00:37:34,734 --> 00:37:36,066 But there's a lot more in them... 529 00:37:36,200 --> 00:37:38,834 nitrogen, ammonia, methane. 530 00:37:40,300 --> 00:37:42,967 And where there's methane, there may be olivine. 531 00:37:44,100 --> 00:37:47,967 Enceladus has been at this for at least 100 million years. 532 00:37:48,533 --> 00:37:52,066 It could keep cranking out water for another nine billion years. 533 00:37:54,667 --> 00:37:56,667 Where's all that water coming from? 534 00:38:15,734 --> 00:38:19,467 The blue snowflakes plummet at more than 1,000 miles per hour. 535 00:38:20,367 --> 00:38:23,934 We've come here to the southern hemisphere because 536 00:38:24,066 --> 00:38:26,200 that's where the ice crust is thinnest. 537 00:38:26,533 --> 00:38:29,567 It's only a couple of miles thick. 538 00:38:31,867 --> 00:38:34,266 That's why it's the best possible place to gain access 539 00:38:34,400 --> 00:38:36,834 to the underground ocean. 540 00:38:42,200 --> 00:38:44,300 Okay, now's the time for a warning: 541 00:38:44,433 --> 00:38:47,600 What you see here is entirely based on evidence. 542 00:38:47,734 --> 00:38:49,934 That global ocean, the crazy curtain of geysers, 543 00:38:51,333 --> 00:38:52,900 that weird snow at the surface... 544 00:38:53,800 --> 00:38:55,233 it's all real. 545 00:38:55,367 --> 00:38:57,300 We have multiple observations from the Cassini 546 00:38:57,433 --> 00:39:00,734 mission telling us that this is what awaits us on Enceladus. 547 00:39:03,367 --> 00:39:06,967 But we're about to enter the realm of informed speculation. 548 00:39:07,667 --> 00:39:10,934 This is what the leading space scientists think we might find 549 00:39:11,066 --> 00:39:15,367 when we send a spacecraft to dive straight into the heart of Enceladus. 550 00:39:17,133 --> 00:39:19,834 (geyser erupting) 551 00:39:33,166 --> 00:39:35,934 When water up here is exposed to the vacuum of space, 552 00:39:36,800 --> 00:39:39,934 it turns to snow. 553 00:39:49,367 --> 00:39:52,400 And that scum is the stuff of life... 554 00:39:52,533 --> 00:39:54,867 organic molecules. 555 00:39:55,000 --> 00:39:58,700 It makes you wonder what could be waiting for us down below. 556 00:39:59,734 --> 00:40:01,333 And that's a long way from here, 557 00:40:01,467 --> 00:40:04,266 because we're in an ocean that's about ten times deeper 558 00:40:04,400 --> 00:40:06,800 than the oceans of Earth. 559 00:40:09,900 --> 00:40:12,266 Very promising. 560 00:40:12,400 --> 00:40:16,100 That's carbon and hydrogen, and the pH of the water is 561 00:40:16,233 --> 00:40:18,200 just like the early ocean on Earth. 562 00:40:36,934 --> 00:40:43,266 ♪ ♪ 563 00:41:01,367 --> 00:41:04,100 ♪ ♪ 564 00:41:04,233 --> 00:41:07,200 Why would this City of Life be larger than the one at the 565 00:41:07,333 --> 00:41:09,300 bottom of the ocean on Earth? 566 00:41:13,166 --> 00:41:15,500 Maybe it's because the gravity on Enceladus is so 567 00:41:15,633 --> 00:41:17,800 much weaker than it is on Earth. 568 00:41:18,433 --> 00:41:21,867 With less gravity, the towers are lighter, 569 00:41:22,000 --> 00:41:24,233 and they can grow taller. 570 00:41:27,233 --> 00:41:29,033 The currents are strong, 571 00:41:29,166 --> 00:41:31,433 and they may have toppled some of the towers. 572 00:41:44,033 --> 00:41:46,700 Victor Goldschmidt's olivine. 573 00:41:47,500 --> 00:41:51,100 The rocks have made a place for life. 574 00:41:53,133 --> 00:41:56,333 But has life had enough time to take hold? 575 00:41:57,533 --> 00:42:01,967 All I know is, never underestimate the escape artist. 576 00:42:22,367 --> 00:42:25,100 You know, it's a funny thing about us. 577 00:42:25,233 --> 00:42:27,367 We think we're the story. 578 00:42:27,500 --> 00:42:30,600 We're the end all and be all of the cosmos. 579 00:42:31,100 --> 00:42:34,700 And yet, for all we know, we're just the by-product of 580 00:42:34,834 --> 00:42:37,233 geochemical forces... 581 00:42:37,367 --> 00:42:41,233 ones that are unfolding throughout the universe. 582 00:42:50,533 --> 00:42:54,967 Galaxies make stars, stars make worlds, 583 00:43:00,333 --> 00:43:04,667 and for all we know, planets and moons make life. 584 00:43:07,967 --> 00:43:10,967 Does that make life less wondrous? 585 00:43:11,767 --> 00:43:13,667 Or more? 586 00:43:14,533 --> 00:43:16,133 Captioned by Cotter Captioning Services.