1 00:00:01,394 --> 00:00:05,639 ♪ 2 00:00:05,714 --> 00:00:08,272 Narrator: Since the dawn of humanity, 3 00:00:08,281 --> 00:00:10,992 We have asked the question, 4 00:00:11,001 --> 00:00:14,519 How did our wondrous home come to be? 5 00:00:17,401 --> 00:00:24,039 Today, space technology casts light on this mystery. 6 00:00:24,121 --> 00:00:26,352 Thanks to intrepid astronauts 7 00:00:26,361 --> 00:00:30,672 And data beamed from hundreds of satellites, 8 00:00:30,681 --> 00:00:35,792 We are gaining new insight into earth's epic history. 9 00:00:35,801 --> 00:00:37,232 Woman: Going to space, 10 00:00:37,241 --> 00:00:41,639 We have a different lens to look at the whole planet. 11 00:00:41,714 --> 00:00:43,872 Narrator: We're finding fresh evidence 12 00:00:43,881 --> 00:00:47,319 To answer age-old questions 13 00:00:47,394 --> 00:00:50,759 About the formation of our solar system. 14 00:00:50,834 --> 00:00:53,072 Man: We can only understand the big picture 15 00:00:53,121 --> 00:00:54,839 When we study all these bodies 16 00:00:54,914 --> 00:00:59,232 And learn everything they have to tell us. 17 00:00:59,241 --> 00:01:04,359 Narrator: We're asking how life begins 18 00:01:04,434 --> 00:01:09,072 And how it evolves through times of peril. 19 00:01:09,081 --> 00:01:10,592 Man: All of these stories 20 00:01:10,601 --> 00:01:13,879 Are intensely interesting murder mysteries 21 00:01:13,954 --> 00:01:15,479 In our planet's past. 22 00:01:18,034 --> 00:01:23,479 Narrator: We're going on a 4.5-billion-year journey 23 00:01:23,554 --> 00:01:30,039 Through eons of fire and meteor storms, 24 00:01:30,114 --> 00:01:33,079 From the arrival of oceans 25 00:01:33,154 --> 00:01:36,439 And freezing global ice sheets, 26 00:01:36,514 --> 00:01:39,159 Through epic eruptions 27 00:01:39,234 --> 00:01:41,799 And mass extinctions, 28 00:01:41,874 --> 00:01:47,632 To where, against all odds, life finds a way. 29 00:01:47,641 --> 00:01:54,199 ♪ 30 00:01:57,401 --> 00:02:02,992 This is the story of the life of earth from space. 31 00:02:03,001 --> 00:02:08,839 ♪ 32 00:02:14,041 --> 00:02:19,072 ♪ 33 00:02:19,201 --> 00:02:21,712 [radio chatter] 34 00:02:21,721 --> 00:02:27,479 250 miles over our heads orbits the international space station. 35 00:02:27,554 --> 00:02:35,152 ♪ 36 00:02:35,161 --> 00:02:37,199 The astronauts who live here 37 00:02:37,241 --> 00:02:39,719 Constantly monitor the world below. 38 00:02:39,794 --> 00:02:46,192 ♪ 39 00:02:46,201 --> 00:02:48,112 Cady coleman: Our vantage point from space 40 00:02:48,121 --> 00:02:50,039 Gives us a view of the planet 41 00:02:50,121 --> 00:02:52,672 That is about collecting information 42 00:02:52,681 --> 00:02:56,352 That can't be collected any other way. 43 00:02:56,361 --> 00:02:58,832 Narrator: But they can also observe phenomena 44 00:02:58,841 --> 00:03:03,959 That provide clues to earth's distant origins, 45 00:03:04,034 --> 00:03:09,079 The countless tiny meteors bombarding our atmosphere. 46 00:03:09,154 --> 00:03:10,279 Coleman: Every single day, 47 00:03:10,354 --> 00:03:13,079 There are thousands and thousands of pounds 48 00:03:13,154 --> 00:03:16,039 Of space rocks pummeling the earth, 49 00:03:16,201 --> 00:03:19,632 And it becomes very clear that we live in a neighborhood. 50 00:03:19,641 --> 00:03:21,552 It's made up of pieces of the universe, 51 00:03:21,561 --> 00:03:27,239 Some of which come crashing down onto our earth. 52 00:03:27,314 --> 00:03:29,072 Narrator: As they enter the atmosphere, 53 00:03:29,161 --> 00:03:31,552 Most of these space rocks burn up, 54 00:03:31,561 --> 00:03:33,072 But those that don't 55 00:03:33,201 --> 00:03:37,559 Can help us understand where our planet came from. 56 00:03:37,634 --> 00:03:41,719 ♪ 57 00:03:41,794 --> 00:03:44,199 50,000 years ago, 58 00:03:44,274 --> 00:03:47,919 A large meteor punches through the atmosphere. 59 00:03:52,121 --> 00:03:57,552 The impact site is today visible from space-- 60 00:03:57,561 --> 00:04:00,639 Arizona's barringer crater. 61 00:04:04,921 --> 00:04:07,312 When the 30-ton meteorite hit, 62 00:04:07,321 --> 00:04:10,199 It exploded into thousands of pieces. 63 00:04:13,881 --> 00:04:16,432 At the national museum of natural history, 64 00:04:16,441 --> 00:04:22,119 A major fragment is on display-- 65 00:04:22,194 --> 00:04:25,079 The canyon diablo, 66 00:04:25,154 --> 00:04:29,559 One of the oldest objects you'll ever see. 67 00:04:29,634 --> 00:04:32,519 Radiometric dating reveals its oldest parts 68 00:04:32,594 --> 00:04:38,279 Formed almost four and a half billion years ago. 69 00:04:38,354 --> 00:04:41,079 Hakeem oluseyi: These meteorites hold in them 70 00:04:41,154 --> 00:04:43,712 A history of our solar system. 71 00:04:43,721 --> 00:04:46,119 They're sort of like fossil relics 72 00:04:46,194 --> 00:04:51,639 That have a story to tell about the birth of earth. 73 00:04:51,714 --> 00:04:54,752 Narrator: It's a story that starts with the building blocks 74 00:04:54,761 --> 00:04:57,552 Of everything on earth, 75 00:04:57,561 --> 00:05:02,439 Elements that are forged in the hearts of long-dead stars. 76 00:05:02,514 --> 00:05:07,232 ♪ 77 00:05:07,241 --> 00:05:11,479 Under its own gravity, an enormous star collapses. 78 00:05:11,554 --> 00:05:15,552 ♪ 79 00:05:15,561 --> 00:05:17,472 [explosion] 80 00:05:17,481 --> 00:05:22,832 The explosion creates elements like iron, oxygen, and carbon. 81 00:05:22,841 --> 00:05:24,439 Oluseyi: The materials that we're made of, 82 00:05:24,514 --> 00:05:27,392 The materials that everything around us is made of, 83 00:05:27,401 --> 00:05:30,839 That earth is made of, these materials, these elements, 84 00:05:30,914 --> 00:05:33,552 Are created in the centers of stars, 85 00:05:33,561 --> 00:05:38,519 And so we are made up of the ashes of exploding stars. 86 00:05:41,641 --> 00:05:44,119 Narrator: As gravity pulls on the stardust, 87 00:05:44,194 --> 00:05:47,319 It forms a hot, spinning disc. 88 00:05:47,394 --> 00:05:52,719 A new star grows in its center-- our sun. 89 00:05:55,394 --> 00:05:59,879 Around it, hot, dusty materials clump together. 90 00:05:59,954 --> 00:06:05,239 These small masses will become comets, asteroids, or meteors, 91 00:06:05,314 --> 00:06:07,239 Like the canyon diablo. 92 00:06:09,634 --> 00:06:14,119 The largest of them become planets, like our own. 93 00:06:14,194 --> 00:06:18,759 ♪ 94 00:06:18,834 --> 00:06:23,239 The infant earth is born. 95 00:06:23,314 --> 00:06:28,759 Its surface is a hellish ocean of molten rock, 96 00:06:28,834 --> 00:06:31,919 And it's missing a crucial companion. 97 00:06:38,841 --> 00:06:40,119 For humanity, 98 00:06:40,194 --> 00:06:43,552 The moon has always been a source of wonder... 99 00:06:46,434 --> 00:06:50,199 A timepiece to chart the months and seasons. 100 00:06:53,081 --> 00:06:55,792 Modern scientists are also captivated 101 00:06:55,801 --> 00:07:01,632 By our closest celestial neighbor. 102 00:07:01,641 --> 00:07:04,592 For them, it is the moon's origins 103 00:07:04,601 --> 00:07:07,552 That remain the greatest mystery. 104 00:07:10,434 --> 00:07:14,992 Is it a smaller body formed in parallel with the earth 105 00:07:15,001 --> 00:07:19,392 Or a passing planet captured by earth's gravity? 106 00:07:19,401 --> 00:07:25,399 ♪ 107 00:07:25,474 --> 00:07:29,152 Nasa's apollo missions provided a unique opportunity 108 00:07:29,161 --> 00:07:31,079 To find the answer. 109 00:07:34,441 --> 00:07:40,672 December 1972, the launch of apollo 17. 110 00:07:40,681 --> 00:07:44,832 On board is dr. Harrison schmitt. 111 00:07:44,841 --> 00:07:47,239 On this last mission to the moon, 112 00:07:47,314 --> 00:07:50,439 Nasa sends their first geologist. 113 00:07:50,514 --> 00:07:55,879 ♪ 114 00:07:59,801 --> 00:08:02,839 Man on radio: 25 feet. Down at 2. 115 00:08:02,914 --> 00:08:06,199 Feels good. 20 feet. 116 00:08:06,274 --> 00:08:07,959 10 feet. 117 00:08:09,881 --> 00:08:13,479 Engines stopped. Ok, houston, the challenger has landed. 118 00:08:16,201 --> 00:08:20,039 Narrator: Scientists believe the secret to the moon's origins 119 00:08:20,114 --> 00:08:22,112 May be hiding in its rocks, 120 00:08:22,121 --> 00:08:25,959 If they can identify the right ones. 121 00:08:26,034 --> 00:08:27,319 Harrison schmitt: My mission was a little bit different 122 00:08:27,394 --> 00:08:29,472 Because we built in some time for me, 123 00:08:29,481 --> 00:08:31,712 As a geologist, to look around 124 00:08:31,721 --> 00:08:37,072 And try to understand more than a pilot astronaut-- 125 00:08:37,081 --> 00:08:38,439 However well-trained they might be, 126 00:08:38,514 --> 00:08:41,399 They didn't have the experience that I did. 127 00:08:41,474 --> 00:08:43,159 Astronaut: Let's see if I can't crack the corner 128 00:08:43,234 --> 00:08:46,032 And get that contact. 129 00:08:46,041 --> 00:08:48,039 Schmitt: We actually collected more than any other mission, 130 00:08:48,114 --> 00:08:51,559 About 240 pounds of rocks. 131 00:08:51,634 --> 00:08:53,959 Narrator: With his carefully selected specimens, 132 00:08:54,034 --> 00:08:56,359 Schmitt hits pay dirt. 133 00:08:58,601 --> 00:09:02,119 These rocks prove that the earth and moon 134 00:09:02,194 --> 00:09:06,512 Are more than just neighbors. 135 00:09:06,521 --> 00:09:09,392 Oluseyi: What those rocks showed is that the moon was made up 136 00:09:09,401 --> 00:09:11,639 Of pretty much the same stuff as the earth, 137 00:09:11,714 --> 00:09:14,519 And so that gave us the big clue that we needed 138 00:09:14,594 --> 00:09:16,512 To understand how the moon formed 139 00:09:16,521 --> 00:09:19,279 But also understand the early history of earth. 140 00:09:21,554 --> 00:09:24,039 Narrator: It's now widely believed that the moon 141 00:09:24,114 --> 00:09:27,959 Is the remnant of a catastrophic collision. 142 00:09:28,034 --> 00:09:33,552 ♪ 143 00:09:33,561 --> 00:09:36,759 A newly formed planet the size of mars 144 00:09:36,834 --> 00:09:39,712 Heads straight towards the infant earth. 145 00:09:39,721 --> 00:09:44,559 ♪ 146 00:09:54,041 --> 00:09:58,599 From the molten debris, our moon takes form, 147 00:09:58,674 --> 00:10:03,959 The same size as it is today, but 17 times closer. 148 00:10:04,034 --> 00:10:06,839 Oluseyi: It took a lot less time to orbit the earth, 149 00:10:06,914 --> 00:10:08,192 And it took a lot less time 150 00:10:08,201 --> 00:10:10,599 For the earth to spin once on its spin axis, 151 00:10:10,674 --> 00:10:13,792 So the day was shorter, the month was shorter, 152 00:10:13,801 --> 00:10:15,552 The week was shorter. 153 00:10:15,561 --> 00:10:19,552 ♪ 154 00:10:19,561 --> 00:10:22,672 Narrator: The proximity of this large circling object 155 00:10:22,681 --> 00:10:26,959 Distorts the earth, causing a tidal effect in the rock. 156 00:10:28,594 --> 00:10:30,192 Oluseyi: There was a gravitational interaction 157 00:10:30,201 --> 00:10:33,312 Between the earth and the moon that we call the tidal force, 158 00:10:33,321 --> 00:10:34,599 And that has the effect 159 00:10:34,674 --> 00:10:37,199 Of throwing the moon away from earth, 160 00:10:37,241 --> 00:10:38,752 So every day, 161 00:10:38,761 --> 00:10:41,319 The moon moves a little bit farther away from the earth 162 00:10:41,394 --> 00:10:42,912 Than it was the day before. 163 00:10:42,921 --> 00:10:49,232 ♪ 164 00:10:49,241 --> 00:10:54,079 Narrator: Now, as the moon rises for the first time, 165 00:10:54,121 --> 00:10:58,359 Our planet begins to cool, 166 00:10:58,434 --> 00:11:01,279 And a crust begins to form. 167 00:11:04,514 --> 00:11:07,872 But before earth can truly come to life, 168 00:11:07,881 --> 00:11:13,072 It must survive another harrowing challenge from space. 169 00:11:13,081 --> 00:11:19,959 ♪ 170 00:11:21,561 --> 00:11:24,119 Narrator: The moon's barren surface 171 00:11:24,194 --> 00:11:27,119 Bears the scars of the distant past. 172 00:11:29,561 --> 00:11:33,959 In 1972, in the rocks around their spacecraft, 173 00:11:34,034 --> 00:11:37,312 Harrison schmitt and the crew of apollo 17 174 00:11:37,321 --> 00:11:40,439 See signs of an impact so intense, 175 00:11:40,514 --> 00:11:44,112 It melted the moon's crust. 176 00:11:44,121 --> 00:11:50,199 They'd landed inside an enormous crater 400 miles wide. 177 00:11:51,241 --> 00:11:52,839 Schmitt: We were in a valley 178 00:11:52,914 --> 00:11:55,312 Deeper than the grand canyon of the united states, 179 00:11:55,321 --> 00:11:59,959 So it was really a remarkable place to be. 180 00:12:00,034 --> 00:12:02,599 Narrator: The crater is one of many thousands 181 00:12:02,674 --> 00:12:05,232 That dot the moon's surface, 182 00:12:05,241 --> 00:12:07,879 And analysis of apollo rocks reveal 183 00:12:07,954 --> 00:12:12,192 Many of these epic craters are truly ancient, 184 00:12:12,201 --> 00:12:15,552 Evidence that beginning some 4 billion years ago, 185 00:12:15,561 --> 00:12:20,112 The inner solar system suffers an intense bombardment. 186 00:12:20,121 --> 00:12:22,759 Schmitt: The major thing that we have learned 187 00:12:22,834 --> 00:12:25,319 Is that the first billion years of earth's history 188 00:12:25,394 --> 00:12:27,719 Was extraordinarily violent. 189 00:12:31,721 --> 00:12:36,439 ♪ 190 00:12:36,514 --> 00:12:39,119 Narrator: Across hundreds of millions of years, 191 00:12:39,161 --> 00:12:44,112 The earth is hit by over 22,000 asteroids and comets 192 00:12:44,121 --> 00:12:47,072 From the outer solar system. 193 00:12:47,081 --> 00:12:52,352 Some are over 25 miles across. 194 00:12:52,361 --> 00:12:56,279 Each one inflicts cataclysmic destruction. 195 00:12:56,354 --> 00:12:57,639 [explosion] 196 00:12:57,714 --> 00:12:58,992 Oluseyi: What would that feel like? 197 00:12:59,001 --> 00:13:00,752 Constant earthquakes, 198 00:13:00,761 --> 00:13:03,559 Objects are streaking through the sky, falling to earth. 199 00:13:03,634 --> 00:13:05,639 You feel the ground shaking, 200 00:13:05,714 --> 00:13:09,159 Giant plumes of material being thrown up. 201 00:13:09,234 --> 00:13:11,072 That would have been amazing. 202 00:13:11,081 --> 00:13:14,832 There is lightning that's created in the plume of dust. 203 00:13:14,841 --> 00:13:19,319 There are rocks that are falling and look like they're on fire. 204 00:13:19,394 --> 00:13:21,712 There's going to be a lot of molten rock 205 00:13:21,721 --> 00:13:23,952 On earth's surface, as well. 206 00:13:23,961 --> 00:13:26,672 You think of darkness. You think of lava. 207 00:13:26,681 --> 00:13:28,992 You think of the smell of sulfur. 208 00:13:31,874 --> 00:13:34,039 Narrator: As this assault continues, 209 00:13:34,114 --> 00:13:36,832 The earth's appearance changes. 210 00:13:39,714 --> 00:13:43,039 Water starts to pool on the earth's surface. 211 00:13:46,601 --> 00:13:49,159 It's thought that the comets bombarding earth 212 00:13:49,234 --> 00:13:53,072 Are laden with ice. 213 00:13:53,081 --> 00:13:54,592 This combines with water 214 00:13:54,601 --> 00:13:58,032 Leaching from the earth's own cooling rocks. 215 00:13:58,041 --> 00:14:02,119 ♪ 216 00:14:02,194 --> 00:14:04,839 The first oceans are born. 217 00:14:12,441 --> 00:14:15,632 With water comes weather. 218 00:14:15,641 --> 00:14:20,599 ♪ 219 00:14:20,674 --> 00:14:26,039 1,000-year relentless storms of unimaginable ferocity. 220 00:14:26,114 --> 00:14:29,072 [thunder] 221 00:14:29,081 --> 00:14:33,519 ♪ 222 00:14:37,481 --> 00:14:41,872 Every tide like a mega tsunami. 223 00:14:41,881 --> 00:14:43,639 Oluseyi: The moon was much closer to the earth, 224 00:14:43,714 --> 00:14:46,432 And this means that the tides were much greater, 225 00:14:46,441 --> 00:14:48,519 So instead of measuring tides in feet, 226 00:14:48,594 --> 00:14:51,639 Tides were measured in kilometers or miles. 227 00:14:51,714 --> 00:14:56,399 ♪ 228 00:15:07,081 --> 00:15:09,479 Narrator: 4 billion years ago, 229 00:15:09,554 --> 00:15:13,559 500 million years after the earth was born, 230 00:15:13,634 --> 00:15:17,072 It has a moon, oceans, and weather. 231 00:15:17,081 --> 00:15:20,759 It is beginning to resemble the planet we know. 232 00:15:20,834 --> 00:15:25,199 For now, it is barren, devoid of life, 233 00:15:25,241 --> 00:15:28,039 But things are about to change. 234 00:15:31,401 --> 00:15:36,199 2013, chelyabinsk, russia. 235 00:15:36,274 --> 00:15:39,559 A traveler arrives from deep space. 236 00:15:39,634 --> 00:15:45,879 ♪ 237 00:15:51,554 --> 00:15:52,519 [crash] 238 00:15:52,594 --> 00:15:54,032 [screaming] 239 00:15:54,041 --> 00:15:56,432 [crashing] 240 00:15:56,441 --> 00:16:00,192 It is the largest meteorite impact in a century. 241 00:16:03,081 --> 00:16:06,432 The hunt is on to find its scattered remains. 242 00:16:06,441 --> 00:16:11,239 ♪ 243 00:16:16,841 --> 00:16:20,519 Scientists pull a huge fragment from a nearby lake. 244 00:16:20,594 --> 00:16:26,112 ♪ 245 00:16:26,121 --> 00:16:31,239 They cut it open and make a fabulous find. 246 00:16:31,314 --> 00:16:35,159 The space rock contains primitive organic materials. 247 00:16:35,234 --> 00:16:40,039 ♪ 248 00:16:40,114 --> 00:16:46,039 It's the latest evidence to support a growing idea-- 249 00:16:46,161 --> 00:16:50,352 That the same comets and meteors that carried water to earth 250 00:16:50,361 --> 00:16:54,399 Also brought with them the ingredients for life. 251 00:17:00,274 --> 00:17:02,599 4 billion years ago, 252 00:17:02,674 --> 00:17:06,519 Auroras illuminate the infant atmosphere, 253 00:17:06,594 --> 00:17:10,912 The visual manifestation of the earth's magnetic field 254 00:17:10,921 --> 00:17:16,199 Produced by its molten core. 255 00:17:16,274 --> 00:17:19,312 It's a shield that now protects the surface 256 00:17:19,321 --> 00:17:22,519 From the ravages of space radiation. 257 00:17:22,594 --> 00:17:28,992 ♪ 258 00:17:29,001 --> 00:17:30,439 Beneath this shield, 259 00:17:30,514 --> 00:17:36,199 In shallow coastal seas churned by the tides of the moon, 260 00:17:36,274 --> 00:17:38,279 Fueled by volcanic heat 261 00:17:38,354 --> 00:17:42,399 And seeded with organic molecules from space... 262 00:17:45,874 --> 00:17:49,552 Comes the very first life on earth. 263 00:17:49,561 --> 00:17:54,112 ♪ 264 00:17:54,121 --> 00:17:57,632 Just how it begins remains a mystery. 265 00:17:57,641 --> 00:18:00,832 But at some point in this distant time, 266 00:18:00,841 --> 00:18:04,032 Chemistry becomes biology. 267 00:18:04,041 --> 00:18:10,359 ♪ 268 00:18:17,481 --> 00:18:20,999 For years, no one believed life could exist 269 00:18:21,074 --> 00:18:24,359 In toxic volcanic environments, 270 00:18:24,434 --> 00:18:28,432 But life is full of surprises. 271 00:18:28,441 --> 00:18:32,439 Today our planet is much changed, 272 00:18:32,514 --> 00:18:34,679 But there remain some environments 273 00:18:34,754 --> 00:18:39,959 Bearing similarities to early earth-- 274 00:18:40,034 --> 00:18:41,559 Iceland, 275 00:18:41,634 --> 00:18:45,399 One of the most volcanic regions of earth. 276 00:18:45,474 --> 00:18:47,399 Just off its southern coast 277 00:18:47,474 --> 00:18:51,072 Lies an isolated volcano named surtsey. 278 00:18:51,081 --> 00:18:56,039 ♪ 279 00:18:56,201 --> 00:19:00,832 Surtsey is one of earth's newest strips of land. 280 00:19:00,841 --> 00:19:05,319 ♪ 281 00:19:05,394 --> 00:19:10,432 In 1963, it exploded from the sea, 282 00:19:10,441 --> 00:19:14,559 Erupting continuously for four years. 283 00:19:16,434 --> 00:19:20,279 ♪ 284 00:19:20,354 --> 00:19:24,352 It is now a world heritage site, 285 00:19:24,361 --> 00:19:28,679 Off-limits to all except a few research scientists. 286 00:19:32,121 --> 00:19:35,319 Surtsey's hot volcanic cracks and seams 287 00:19:35,394 --> 00:19:41,639 Closely reproduce the environment of early earth. 288 00:19:41,714 --> 00:19:46,432 The team drills cores of rock from hundreds of feet below. 289 00:19:46,441 --> 00:19:50,359 ♪ 290 00:19:50,434 --> 00:19:53,559 They search for the fingerprints of life, 291 00:19:53,634 --> 00:19:58,439 Marks made in the rock by deep-dwelling microorganisms. 292 00:19:58,514 --> 00:20:02,992 ♪ 293 00:20:03,001 --> 00:20:07,559 Despite temperatures exceeding 250 degrees fahrenheit, 294 00:20:07,634 --> 00:20:11,399 Without oxygen, and in acidic, salty water, 295 00:20:11,474 --> 00:20:14,199 The rocks are clearly scarred 296 00:20:14,274 --> 00:20:18,592 By single-celled organisms feeding off the rock. 297 00:20:21,474 --> 00:20:25,312 Scientists are now finding these extremophile cells 298 00:20:25,321 --> 00:20:30,439 In volcanic zones across the globe. 299 00:20:30,514 --> 00:20:32,272 Steffen jørgensen: It's mind-blowing, to be honest, 300 00:20:32,281 --> 00:20:36,519 Because the number of microbial cells found in this system 301 00:20:36,594 --> 00:20:40,359 Outcompete the number of stars in the universe. 302 00:20:40,434 --> 00:20:43,559 Narrator: Dna indicates some underground microbes 303 00:20:43,634 --> 00:20:46,912 Relate closely to cells that were ancestors 304 00:20:46,921 --> 00:20:50,672 Of all life on the surface. 305 00:20:50,681 --> 00:20:52,272 Jørgensen: It dawned on me at that time 306 00:20:52,281 --> 00:20:54,439 Just how important they are. 307 00:20:54,514 --> 00:20:56,272 These are the type of cells 308 00:20:56,281 --> 00:21:00,352 That evolved into a more complex cell structure, 309 00:21:00,361 --> 00:21:03,479 Which eventually turned into you and I. 310 00:21:03,554 --> 00:21:07,439 ♪ 311 00:21:21,321 --> 00:21:24,599 Narrator: 3 billion years ago, 312 00:21:24,674 --> 00:21:29,679 Simple single-celled life forms are now colonizing the planet. 313 00:21:33,481 --> 00:21:37,799 The oceans swirl with blue-green cyanobacteria. 314 00:21:37,874 --> 00:21:45,152 ♪ 315 00:21:45,161 --> 00:21:46,519 These have now evolved 316 00:21:46,594 --> 00:21:49,479 To harness the energy of sunlight... 317 00:21:52,354 --> 00:21:55,159 Through photosynthesis, 318 00:21:55,234 --> 00:22:01,479 The process still used by modern plants. 319 00:22:01,554 --> 00:22:06,599 This revolution in energy supply has massive consequences... 320 00:22:10,434 --> 00:22:13,759 Because the byproduct is oxygen. 321 00:22:16,914 --> 00:22:18,672 Over the next billion years, 322 00:22:18,681 --> 00:22:22,439 Cyanobacteria turn carbon dioxide into oxygen 323 00:22:22,514 --> 00:22:27,399 In such volumes that the entire ecosystem alters. 324 00:22:30,521 --> 00:22:35,479 The crust of the earth and the oceans are filled with iron. 325 00:22:35,554 --> 00:22:38,039 As oxygen leaches into the system, 326 00:22:38,114 --> 00:22:42,992 This iron is transformed. 327 00:22:43,001 --> 00:22:45,312 Kirk johnson: There's lots of iron on the planet's surface, 328 00:22:45,321 --> 00:22:46,919 But it had never been oxidized before, 329 00:22:46,994 --> 00:22:50,512 So, fundamentally, cyanobacteria created oxygen, 330 00:22:50,521 --> 00:22:53,959 Which created rust, and the earth became red. 331 00:22:54,034 --> 00:23:02,119 ♪ 332 00:23:02,194 --> 00:23:04,112 Narrator: By 2 billion years ago, 333 00:23:04,121 --> 00:23:08,279 The countless tiny microbes that fill the earth's oceans 334 00:23:08,354 --> 00:23:11,072 Alter the chemistry of the planet. 335 00:23:11,121 --> 00:23:14,039 ♪ 336 00:23:14,161 --> 00:23:19,232 But as it slowly evolves over the next billion years, 337 00:23:19,241 --> 00:23:23,239 Life will face a new challenge to its existence, 338 00:23:23,314 --> 00:23:25,072 As changes in climate 339 00:23:25,081 --> 00:23:29,159 Plunge the planet into deep freeze. 340 00:23:32,201 --> 00:23:36,352 720 million years ago, 341 00:23:36,361 --> 00:23:40,359 Earth is set for an explosion of life, 342 00:23:40,434 --> 00:23:44,832 But for now, life remains primitive and rare, 343 00:23:44,841 --> 00:23:49,872 And some scientists believe they know why. 344 00:23:49,881 --> 00:23:51,399 Satellite and ground surveys 345 00:23:51,474 --> 00:23:55,159 Across a 2,000-mile stretch of northern canada 346 00:23:55,234 --> 00:24:01,359 Capture evidence of an ancient continent-sized volcanic field. 347 00:24:03,721 --> 00:24:10,119 This is the franklin large igneous province. 348 00:24:10,194 --> 00:24:12,039 Many scientists now believe 349 00:24:12,121 --> 00:24:16,352 It's the sign of a series of enormous volcanic eruptions 350 00:24:16,361 --> 00:24:22,672 That threatened life on earth by blotting out the sun. 351 00:24:22,681 --> 00:24:25,079 [rumbling] 352 00:24:25,154 --> 00:24:28,199 1991, the philippines. 353 00:24:28,274 --> 00:24:32,039 Mount pinatubo explodes. 354 00:24:32,114 --> 00:24:38,519 It's one of the biggest volcanic eruptions of the modern era. 355 00:24:38,594 --> 00:24:43,639 Pinatubo pumps over 10 million tons of sulfur into the skies. 356 00:24:45,634 --> 00:24:47,639 Satellites later record a change 357 00:24:47,714 --> 00:24:51,152 In reflectivity of the atmosphere. 358 00:24:51,161 --> 00:24:54,432 So much heat energy bounces back into space, 359 00:24:54,441 --> 00:24:58,679 The whole earth cools by one degree fahrenheit. 360 00:25:01,641 --> 00:25:06,079 Imagine the impact of multiple pinatubo eruptions 361 00:25:06,121 --> 00:25:08,279 All going off at once. 362 00:25:08,354 --> 00:25:13,959 ♪ 363 00:25:14,034 --> 00:25:16,759 Northern canada. 364 00:25:16,834 --> 00:25:21,719 Across 2,000 miles, the earth tears open. 365 00:25:21,794 --> 00:25:25,799 ♪ 366 00:25:25,874 --> 00:25:30,752 Billions of tons of sulfur and ash clog the air. 367 00:25:30,761 --> 00:25:37,152 ♪ 368 00:25:37,161 --> 00:25:41,312 The earth plunges into darkness. 369 00:25:41,321 --> 00:25:43,632 [explosion] 370 00:25:43,641 --> 00:25:47,079 The eruption continues for decades. 371 00:25:47,154 --> 00:25:54,199 ♪ 372 00:25:54,274 --> 00:25:59,279 Global temperatures plummet to minus 50 degrees fahrenheit. 373 00:26:01,321 --> 00:26:04,672 One theory suggests the freeze is so intense, 374 00:26:04,681 --> 00:26:09,872 The planet is encased in ice-- 375 00:26:09,881 --> 00:26:14,119 Snowball earth-- 376 00:26:14,194 --> 00:26:19,239 Entombing earth's fragile microbes beneath miles of ice 377 00:26:19,314 --> 00:26:22,039 For 80 million years. 378 00:26:22,114 --> 00:26:28,199 ♪ 379 00:26:28,274 --> 00:26:34,039 But eventually the ice thaws. 380 00:26:34,201 --> 00:26:38,992 Somehow, life on earth survives, 381 00:26:39,001 --> 00:26:45,079 And now it will thrive. 382 00:26:45,154 --> 00:26:48,359 Across the next 200 million years, 383 00:26:48,434 --> 00:26:52,039 New generations of bacterial blooms 384 00:26:52,114 --> 00:26:56,119 Raise oxygen levels again, 385 00:26:56,194 --> 00:27:01,159 Creating an atmosphere rich in oxygen. 386 00:27:01,234 --> 00:27:04,432 Coleman: Looking at the earth, especially at sunrise or sunset, 387 00:27:04,441 --> 00:27:07,399 Which for us happens 16 times a day, 388 00:27:07,474 --> 00:27:09,319 Which is pretty wonderful, 389 00:27:09,394 --> 00:27:12,192 That's when you can really see 390 00:27:12,201 --> 00:27:15,159 That, that layer, that, that thin atmosphere, 391 00:27:15,234 --> 00:27:17,079 And it's like a little bubble 392 00:27:17,154 --> 00:27:20,199 That encloses everything you know and love. 393 00:27:22,914 --> 00:27:27,232 Narrator: 600 million years ago, this oxygen-rich environment 394 00:27:27,241 --> 00:27:31,552 Is the catalyst for an energy revolution. 395 00:27:31,561 --> 00:27:38,159 Some microbes now turn from solar power to oxygen power. 396 00:27:38,201 --> 00:27:41,639 This new energy source is behind their evolution 397 00:27:41,714 --> 00:27:45,439 Into the first multicellular plants and animals. 398 00:27:48,674 --> 00:27:51,872 Today, off the coast of australia 399 00:27:51,881 --> 00:27:56,352 Lies the great barrier reef, 400 00:27:56,361 --> 00:28:01,072 An organic structure so big, it can be seen from space. 401 00:28:01,081 --> 00:28:07,799 ♪ 402 00:28:09,714 --> 00:28:15,712 Scientists believe ancient reefs were incubators for early life. 403 00:28:15,721 --> 00:28:18,752 They are among the most ecologically diverse places 404 00:28:18,761 --> 00:28:20,352 On our planet. 405 00:28:20,361 --> 00:28:23,479 ♪ 406 00:28:31,634 --> 00:28:33,239 Johnson: Reefs are like cities. 407 00:28:33,314 --> 00:28:35,472 I mean, cities, you start with a few little houses. 408 00:28:35,481 --> 00:28:37,472 Then you get buildings and multi-story buildings. 409 00:28:37,481 --> 00:28:39,392 There's lots of diversity in a city, 410 00:28:39,401 --> 00:28:41,952 So in ancient reefs, there's just that same thing. 411 00:28:41,961 --> 00:28:43,639 The more kinds of places there were to live, 412 00:28:43,714 --> 00:28:46,519 The more diversity of life forms there were. 413 00:28:50,194 --> 00:28:51,472 Narrator: In southern africa, 414 00:28:51,481 --> 00:28:53,079 Scientists have recently discovered 415 00:28:53,154 --> 00:28:58,912 What they believe is one of the oldest reefs on the planet. 416 00:28:58,921 --> 00:29:04,759 It was formed in oxygen-rich seas 550 million years ago. 417 00:29:04,834 --> 00:29:09,472 ♪ 418 00:29:09,481 --> 00:29:15,239 Evidence suggests this is a time of rapid evolutionary change. 419 00:29:15,314 --> 00:29:18,112 This is when the blueprint of modern animals, 420 00:29:18,121 --> 00:29:22,439 Of us, first emerges-- 421 00:29:22,514 --> 00:29:24,999 The cambrian explosion. 422 00:29:27,401 --> 00:29:33,872 Johnson: What we see are a bunch of new kinds of organisms. 423 00:29:33,881 --> 00:29:35,239 Now, these were marine animals, 424 00:29:35,314 --> 00:29:38,119 Small animals that looked like crabs and shrimp 425 00:29:38,194 --> 00:29:39,952 And other kinds of shellfish. 426 00:29:39,961 --> 00:29:43,312 These organisms had features that are quite familiar to us. 427 00:29:43,321 --> 00:29:46,272 If you look at a, a little tiny crab, 428 00:29:46,281 --> 00:29:48,352 He's got little eyes looking back at you. 429 00:29:48,361 --> 00:29:50,199 He's got limbs, and he crawls around, 430 00:29:50,274 --> 00:29:51,632 And he eats stuff through his mouth, 431 00:29:51,641 --> 00:29:53,079 And it goes into his stomach, 432 00:29:53,154 --> 00:29:55,159 And it goes out the back end as its waste. 433 00:29:55,234 --> 00:29:57,879 That sort of way of being an animal, 434 00:29:57,954 --> 00:30:00,399 We see for the first time in the cambrian explosion. 435 00:30:05,081 --> 00:30:07,479 Narrator: Over 4 billion years, 436 00:30:07,554 --> 00:30:12,999 The earth evolves from a ball of fire to a ball of ice. 437 00:30:16,201 --> 00:30:21,879 And by 400 million years ago, to this-- 438 00:30:21,954 --> 00:30:25,072 A blue-green planet 439 00:30:25,081 --> 00:30:28,439 With life spreading to the land. 440 00:30:28,514 --> 00:30:31,079 Johnson: Pretty soon after you have the first plants on earth, 441 00:30:31,154 --> 00:30:33,119 You have the first trees on earth. 442 00:30:33,161 --> 00:30:34,832 With trees come forests, 443 00:30:34,841 --> 00:30:37,712 And with forests come the same kind of diversity of habitat 444 00:30:37,721 --> 00:30:41,399 That we've seen underwater in the reef structures. 445 00:30:41,474 --> 00:30:44,679 Narrator: With plant life comes animal life. 446 00:30:44,754 --> 00:30:48,039 The first surface dwellers make their appearance. 447 00:30:48,114 --> 00:30:50,672 Life now has a foothold, 448 00:30:50,681 --> 00:30:54,759 Across land, sea, and the sky. 449 00:30:57,081 --> 00:30:59,159 But their new oasis 450 00:30:59,234 --> 00:31:02,759 Is a time bomb just waiting to explode. 451 00:31:07,634 --> 00:31:09,279 Russia. 452 00:31:12,274 --> 00:31:16,592 These are the siberian traps, 453 00:31:16,601 --> 00:31:23,072 An ancient lava field spread over 2 million square miles. 454 00:31:23,081 --> 00:31:27,632 In 2011, scientists here made a crucial discovery, 455 00:31:27,641 --> 00:31:30,672 Explaining one of the most infamous events 456 00:31:30,681 --> 00:31:33,159 In earth history, 457 00:31:33,234 --> 00:31:35,399 The great dying. 458 00:31:38,121 --> 00:31:39,479 This spot is the scene 459 00:31:39,554 --> 00:31:43,959 Of the most deadly volcanic eruption in history. 460 00:31:44,034 --> 00:31:48,359 ♪ 461 00:31:48,434 --> 00:31:52,039 This huge area becomes an ocean of fire. 462 00:31:52,161 --> 00:31:58,279 ♪ 463 00:31:58,354 --> 00:32:02,199 But the danger is not just the eruption. 464 00:32:02,274 --> 00:32:05,312 Scientists found the lava erupted 465 00:32:05,321 --> 00:32:08,592 Through a thick layer of coal, 466 00:32:08,601 --> 00:32:13,552 Generating a toxic cloud that acidifies the atmosphere, 467 00:32:13,561 --> 00:32:19,639 Leading to about a million years of deadly acid rain. 468 00:32:19,714 --> 00:32:22,999 Johnson: This eruption happens almost precisely 469 00:32:23,074 --> 00:32:27,079 When we see a lot of things go extinct at the same time. 470 00:32:27,154 --> 00:32:31,152 The lava starts erupting, organisms start dying. 471 00:32:31,161 --> 00:32:34,112 We call it the great dying because by our best estimates, 472 00:32:34,121 --> 00:32:37,632 It's pretty close to snuffing out life on the planet. 473 00:32:37,641 --> 00:32:42,199 ♪ 474 00:32:42,274 --> 00:32:46,112 Narrator: But not all life dies out, 475 00:32:46,121 --> 00:32:49,072 And the gaps opened up by the extinction 476 00:32:49,081 --> 00:32:53,799 Generate a monstrous surge in evolution-- 477 00:32:53,874 --> 00:32:57,159 The age of the dinosaurs. 478 00:32:57,234 --> 00:33:01,872 ♪ 479 00:33:01,881 --> 00:33:04,672 Argentina, 2012. 480 00:33:04,681 --> 00:33:10,159 ♪ 481 00:33:10,201 --> 00:33:13,072 Paleontologist dr. Diego pol 482 00:33:13,081 --> 00:33:16,119 Uncovers the remains of what's thought to be 483 00:33:16,194 --> 00:33:20,159 The biggest land animal that ever lived. 484 00:33:20,201 --> 00:33:26,439 So large, its thigh bone alone stood taller than a human. 485 00:33:26,514 --> 00:33:33,479 ♪ 486 00:33:33,554 --> 00:33:37,632 The 70-ton titanosaur. 487 00:33:40,514 --> 00:33:43,799 Diego pol: Can you imagine 10 african elephants put together? 488 00:33:43,874 --> 00:33:47,239 You know, this animal was as long as an airplane, 489 00:33:47,314 --> 00:33:50,032 You know, a boeing 737. 490 00:33:50,041 --> 00:33:54,272 Narrator: But dinosaurs were not always so enormous. 491 00:33:54,281 --> 00:33:55,959 Pol: 230 million years ago, 492 00:33:56,034 --> 00:33:58,992 The first dinosaurs appear on our planet, 493 00:33:59,001 --> 00:34:00,759 And they were tiny animals. 494 00:34:00,834 --> 00:34:04,112 They were probably weighing 10 kilograms. 495 00:34:04,121 --> 00:34:06,759 Now, 50 million years after that... 496 00:34:06,834 --> 00:34:08,039 [thud] 497 00:34:08,114 --> 00:34:09,159 [roaring] 498 00:34:09,234 --> 00:34:11,719 There were the first giant dinosaurs. 499 00:34:14,434 --> 00:34:16,992 This is the time when titanosaur appeared 500 00:34:17,001 --> 00:34:20,439 And when they achieved the maximum body size, 501 00:34:20,514 --> 00:34:24,439 When we started seeing these 70-ton animals 502 00:34:24,514 --> 00:34:26,439 Roaming on our planet. 503 00:34:28,521 --> 00:34:30,199 Narrator: It's not yet clear 504 00:34:30,274 --> 00:34:35,239 What caused dinosaurs like titanosaur to grow so large. 505 00:34:38,114 --> 00:34:40,272 But these enormous plant eaters 506 00:34:40,281 --> 00:34:44,599 Now become an important part of the global ecosystem. 507 00:34:48,114 --> 00:34:51,792 They travel hundreds of miles. 508 00:34:51,801 --> 00:34:55,639 They spread seeds and trample vegetation, 509 00:34:55,714 --> 00:34:58,432 Creating new opportunity for plant species 510 00:34:58,441 --> 00:35:00,999 To spread across the planet. 511 00:35:01,074 --> 00:35:04,112 [roars] 512 00:35:04,121 --> 00:35:06,832 Pol: We know these giant dinosaurs migrated 513 00:35:06,841 --> 00:35:10,199 From antarctica to asia to north america, africa. 514 00:35:10,274 --> 00:35:12,599 They were everywhere, 515 00:35:12,674 --> 00:35:15,079 Roaming through the landscape, 516 00:35:15,154 --> 00:35:18,039 Altering and modifying the different ecosystems 517 00:35:18,121 --> 00:35:20,672 All over the planet. 518 00:35:20,681 --> 00:35:23,952 It's really, really amazing. 519 00:35:27,001 --> 00:35:29,392 Narrator: For 180 million years, 520 00:35:29,401 --> 00:35:32,439 As the continents slowly shift beneath them, 521 00:35:32,514 --> 00:35:36,352 The giant dinosaurs dominate the planet, 522 00:35:36,361 --> 00:35:39,072 But around 65 million years ago, 523 00:35:39,201 --> 00:35:46,039 Suddenly they disappear, wiped out by a meteor strike. 524 00:35:46,114 --> 00:35:48,199 Scientists believe another event 525 00:35:48,274 --> 00:35:50,919 May have contributed to their downfall. 526 00:35:52,914 --> 00:35:57,872 In india today, there is a collection of ancient temples. 527 00:35:57,881 --> 00:36:02,159 These incredible structures were cut from the soft rock 528 00:36:02,201 --> 00:36:04,519 Of the deccan traps, 529 00:36:04,594 --> 00:36:07,472 The remains of a massive lava eruption 530 00:36:07,481 --> 00:36:12,912 That spreads over 200,000 square miles of western india. 531 00:36:12,921 --> 00:36:18,359 ♪ 532 00:36:18,434 --> 00:36:23,392 This epic eruption begins to poison the dinosaurs' world. 533 00:36:23,401 --> 00:36:27,479 ♪ 534 00:36:27,554 --> 00:36:29,472 But the nail in their coffin 535 00:36:29,481 --> 00:36:32,839 Is the sudden impact of an immense meteor. 536 00:36:44,194 --> 00:36:45,639 Johnson: Here you have a body of rock 537 00:36:45,714 --> 00:36:47,232 That's six miles in diameter. 538 00:36:47,241 --> 00:36:50,272 It's traveling at 20 times the speed of a rifle bullet. 539 00:36:50,281 --> 00:36:51,479 When it hits planet earth, 540 00:36:51,554 --> 00:36:53,632 Which is much, much, much larger, 541 00:36:53,641 --> 00:36:56,119 It's like driving a truck into a stone wall. 542 00:36:58,674 --> 00:37:01,152 And it punches a hole deep into the earth. 543 00:37:01,161 --> 00:37:04,399 And then all that energy gets blown back out of that hole. 544 00:37:07,954 --> 00:37:11,472 Narrator: With a force of a billion atomic bombs, 545 00:37:11,481 --> 00:37:13,399 The explosion gouges a crater 546 00:37:13,474 --> 00:37:18,639 115 miles wide and nearly 8 miles deep. 547 00:37:21,401 --> 00:37:24,599 But many now believe that the impact alone 548 00:37:24,674 --> 00:37:29,072 Wasn't powerful enough to cause their global extinction. 549 00:37:29,081 --> 00:37:33,632 ♪ 550 00:37:33,641 --> 00:37:37,792 Satellites designed to search for oil have recently confirmed 551 00:37:37,801 --> 00:37:41,232 That the impact site is a part of the earth's crust 552 00:37:41,241 --> 00:37:45,039 Unusually rich in hydrocarbons and sulfur. 553 00:37:49,874 --> 00:37:54,352 When the meteor hits, the volatile compounds vaporize, 554 00:37:54,361 --> 00:37:57,879 Creating a cocktail of climate-changing chemicals 555 00:37:57,954 --> 00:38:02,039 That mix with the countless tons of melted rock. 556 00:38:02,114 --> 00:38:04,119 Johnson: All that energy blows up and out. 557 00:38:04,194 --> 00:38:06,832 Some of it goes out of the earth's atmosphere. 558 00:38:06,841 --> 00:38:09,392 Some of it blows sideways. 559 00:38:09,401 --> 00:38:11,232 Meanwhile the earth is turning, 560 00:38:11,241 --> 00:38:13,479 So you have hot stuff flying out of the sky 561 00:38:13,554 --> 00:38:15,072 On the other side of the planet. 562 00:38:15,081 --> 00:38:19,399 ♪ 563 00:38:19,474 --> 00:38:21,319 If you were anywhere near it, forget about it, 564 00:38:21,394 --> 00:38:23,399 But if you are on the other side of the planet, 565 00:38:23,474 --> 00:38:25,072 Forget about it also. 566 00:38:25,081 --> 00:38:29,232 ♪ 567 00:38:29,241 --> 00:38:33,792 Narrator: Nearly half of global plant life dies. 568 00:38:33,801 --> 00:38:39,479 Half the life in the sea is snuffed out. 569 00:38:39,554 --> 00:38:44,432 Three quarters of all life on the planet is made extinct. 570 00:38:44,441 --> 00:38:49,552 The great dinosaurs' fate is sealed. 571 00:38:49,561 --> 00:38:52,512 Although they disappear from history, 572 00:38:52,521 --> 00:38:56,039 The catastrophe now creates opportunity 573 00:38:56,114 --> 00:38:59,039 For others to take their place. 574 00:39:05,081 --> 00:39:07,799 65 million years ago... 575 00:39:11,314 --> 00:39:14,199 After the devastating meteor impact, 576 00:39:14,274 --> 00:39:18,999 Over thousands of years, the world slowly recovers. 577 00:39:21,154 --> 00:39:24,992 The air clears, 578 00:39:25,001 --> 00:39:28,272 The fires cool, 579 00:39:28,281 --> 00:39:31,559 And new forests take root. 580 00:39:31,634 --> 00:39:34,479 The great dinosaurs are no more. 581 00:39:35,714 --> 00:39:38,112 [sniffing] 582 00:39:38,121 --> 00:39:40,759 But some life has survived. 583 00:39:43,481 --> 00:39:44,992 Anjali goswami: The mass extinction that saw 584 00:39:45,001 --> 00:39:46,912 The demise of the dinosaurs 585 00:39:46,921 --> 00:39:50,679 Was terrible for everything on the planet quite frankly. 586 00:39:50,754 --> 00:39:52,992 Mammals squeaked through that extinction. 587 00:39:53,001 --> 00:39:56,759 They did not sail through it by any stretch of the imagination. 588 00:39:56,834 --> 00:40:00,592 There might be as few as 20 different kinds of mammals 589 00:40:00,601 --> 00:40:02,512 That made it through that extinction. 590 00:40:02,521 --> 00:40:04,592 But the death of the dinosaurs 591 00:40:04,601 --> 00:40:07,632 Really opened up a huge amount of opportunity for mammals, 592 00:40:07,641 --> 00:40:09,119 And they took it. 593 00:40:09,161 --> 00:40:11,632 They took the opportunity, and they went wild with it. 594 00:40:11,641 --> 00:40:15,479 ♪ 595 00:40:15,554 --> 00:40:17,719 Narrator: On the northern borders of india 596 00:40:17,794 --> 00:40:19,479 Lie the himalayas, 597 00:40:19,554 --> 00:40:24,119 The highest mountain range on earth. 598 00:40:24,194 --> 00:40:29,472 Today its peaks rise five and a half miles above sea level. 599 00:40:29,481 --> 00:40:33,552 ♪ 600 00:40:33,561 --> 00:40:37,312 But by earth's standards, these mountains are young, 601 00:40:37,321 --> 00:40:40,999 Less than 55 million years old. 602 00:40:43,234 --> 00:40:48,119 This epic range rose in parallel with the rise of the mammals. 603 00:40:48,194 --> 00:40:56,039 ♪ 604 00:40:56,114 --> 00:41:02,839 55 million years ago, after eons of continental drift, 605 00:41:02,914 --> 00:41:06,432 India smashes into eurasia. 606 00:41:06,441 --> 00:41:09,712 The himalayas begin their ascent to the heavens. 607 00:41:09,721 --> 00:41:16,272 ♪ 608 00:41:16,281 --> 00:41:18,512 Recent fossil finds in india 609 00:41:18,521 --> 00:41:21,952 Are adding to evidence collected worldwide 610 00:41:21,961 --> 00:41:25,919 That this is an evolutionary turning point. 611 00:41:29,481 --> 00:41:32,992 The precursors of many key mammalian species 612 00:41:33,001 --> 00:41:36,679 Are starting to emerge and spread across the globe. 613 00:41:41,001 --> 00:41:43,399 Goswami: 10 to 20 million years after the dinosaurs go extinct, 614 00:41:43,474 --> 00:41:45,639 Mammals really explore the world 615 00:41:45,714 --> 00:41:50,592 And develop a huge range of shapes and ecologies 616 00:41:50,601 --> 00:41:53,319 That still define them today. 617 00:41:53,394 --> 00:41:57,479 You start to see the first real horses. 618 00:41:57,554 --> 00:42:01,072 You see whales moving into the ocean. 619 00:42:01,081 --> 00:42:04,039 You start to see early primates showing up. 620 00:42:06,841 --> 00:42:12,759 But it was certainly a pivotal moment in mammal history. 621 00:42:12,834 --> 00:42:15,472 Narrator: For the next 50 million years, 622 00:42:15,481 --> 00:42:20,039 As continents continue to shift into today's positions 623 00:42:20,121 --> 00:42:22,999 And the himalayas inch upwards... 624 00:42:26,754 --> 00:42:29,392 The mammals evolve. 625 00:42:29,401 --> 00:42:36,439 ♪ 626 00:42:36,514 --> 00:42:39,312 By one million years ago, 627 00:42:39,321 --> 00:42:41,959 They take over the globe. 628 00:42:42,034 --> 00:42:47,872 ♪ 629 00:42:47,881 --> 00:42:51,072 And in africa, conditions are ripe 630 00:42:51,081 --> 00:42:55,472 For a new chapter in the history of our world. 631 00:42:55,481 --> 00:42:59,472 A new mammal will emerge, 632 00:42:59,481 --> 00:43:05,312 A new type of primate that walks tall, 633 00:43:05,321 --> 00:43:08,039 Who in a flicker of geological time 634 00:43:08,114 --> 00:43:11,479 Will become the dominant species on the planet. 635 00:43:15,081 --> 00:43:20,999 Next time, we'll explore the age of humans, 636 00:43:21,074 --> 00:43:26,192 Using clues from space to provide new insights 637 00:43:26,201 --> 00:43:31,472 Into why we evolved our unique human brain, 638 00:43:31,481 --> 00:43:34,912 How we tamed the planet's animals and plants 639 00:43:34,921 --> 00:43:38,672 To build great civilizations, 640 00:43:38,681 --> 00:43:43,319 And how we develop total command of the earth's energy, 641 00:43:43,394 --> 00:43:47,472 Giving us the power not only to shape our future, 642 00:43:47,481 --> 00:43:51,872 But also the fate of the planet we call home. 643 00:43:51,881 --> 00:43:56,999 ♪