1 00:00:01,251 --> 00:00:03,585 CARL SAGAN: The cosmos is all that is, 2 00:00:03,620 --> 00:00:06,755 or ever was or ever will be. 3 00:00:07,791 --> 00:00:09,124 Come with me. 4 00:00:10,593 --> 00:00:12,561 NEIL DEGRASSE TYSON: A generation ago, 5 00:00:12,595 --> 00:00:14,963 the astronomer Carl Sagan stood here 6 00:00:14,998 --> 00:00:16,965 and launched hundreds of millions of us 7 00:00:17,000 --> 00:00:18,967 on a great adventure-- 8 00:00:19,002 --> 00:00:22,805 the exploration of the universe revealed by science. 9 00:00:22,839 --> 00:00:25,808 It's time to get going again. 10 00:00:25,842 --> 00:00:28,811 We're about to begin a journey that will take us 11 00:00:28,845 --> 00:00:31,914 from the infinitesimal to the infinite, 12 00:00:31,948 --> 00:00:34,917 from the dawn of time to the distant future. 13 00:00:34,951 --> 00:00:39,254 We'll explore galaxies and suns and worlds, 14 00:00:39,289 --> 00:00:42,291 surf the gravity waves of space-time, 15 00:00:42,325 --> 00:00:45,661 encounter beings that live in fire and ice, 16 00:00:45,695 --> 00:00:49,431 explore the planets of stars that never die, 17 00:00:49,466 --> 00:00:52,034 discover atoms as massive as suns 18 00:00:52,068 --> 00:00:56,138 and universes smaller than atoms. 19 00:00:56,172 --> 00:00:59,308 Cosmos is also a story about us. 20 00:00:59,342 --> 00:01:03,479 It's the saga of how wandering bands of hunters and gatherers 21 00:01:03,513 --> 00:01:08,183 found their way to the stars, 22 00:01:08,218 --> 00:01:11,987 one adventure with many heroes. 23 00:01:20,697 --> 00:01:24,166 To make this journey, we'll need imagination. 24 00:01:24,200 --> 00:01:26,502 But imagination alone is not enough 25 00:01:26,536 --> 00:01:29,705 because the reality of nature is far more wondrous 26 00:01:29,739 --> 00:01:32,074 than anything we can imagine. 27 00:01:36,112 --> 00:01:39,748 This adventure is made possible by generations of searchers 28 00:01:39,783 --> 00:01:43,252 strictly adhering to a simple set of rules: 29 00:01:43,286 --> 00:01:47,022 test ideas by experiment and observation, 30 00:01:47,123 --> 00:01:50,008 build on those ideas that pass the test, 31 00:01:50,059 --> 00:01:52,261 reject the ones that fail, 32 00:01:52,295 --> 00:01:54,897 follow the evidence wherever it leads 33 00:01:54,931 --> 00:01:57,566 and question everything. 34 00:01:57,600 --> 00:02:00,068 Accept these terms, 35 00:02:00,103 --> 00:02:04,039 and the cosmos is yours. 36 00:02:04,073 --> 00:02:07,376 Now come with me. 37 00:04:04,360 --> 00:04:06,962 free from the shackles of space and time, 38 00:04:06,996 --> 00:04:10,032 we can go anywhere. 39 00:04:10,066 --> 00:04:12,301 If you want to see where we are in space, 40 00:04:12,335 --> 00:04:15,504 just look out the front window. 41 00:04:19,442 --> 00:04:23,078 In the dimension of time, the past lies beneath us. 42 00:04:25,381 --> 00:04:29,584 Here's what Earth looked like 250 million years ago. 43 00:04:33,189 --> 00:04:35,757 If you want to see the future, look up. 44 00:04:35,792 --> 00:04:41,063 And this is how it could appear 250 million years from now. 45 00:04:42,432 --> 00:04:43,865 If we're going to be venturing out 46 00:04:43,900 --> 00:04:46,735 into the farthest reaches of the cosmos, 47 00:04:46,737 --> 00:04:49,671 we need to know our cosmic address, 48 00:04:49,706 --> 00:04:53,408 and this is the first line of that address. 49 00:05:14,597 --> 00:05:18,967 We're leaving the Earth, the only home we've ever known, 50 00:05:19,002 --> 00:05:23,405 for the farthest reaches of the cosmos. 51 00:05:27,443 --> 00:05:31,313 Our nearest neighbor, the Moon, has no sky, 52 00:05:31,347 --> 00:05:34,750 no ocean, no life-- 53 00:05:34,784 --> 00:05:38,153 just the scars of cosmic impacts. 54 00:05:51,167 --> 00:05:54,136 Our star powers the wind and the waves 55 00:05:54,170 --> 00:05:57,973 and all the life on the surface of our world. 56 00:05:58,007 --> 00:06:00,575 The Sun holds all the worlds of the solar system 57 00:06:00,610 --> 00:06:05,147 in its gravitational embrace, starting with Mercury... 58 00:06:23,699 --> 00:06:27,602 ...to cloud-covered Venus, where runaway greenhouse effect 59 00:06:27,637 --> 00:06:31,239 has turned it into a kind of hell. 60 00:06:37,180 --> 00:06:38,980 Mars... 61 00:06:39,015 --> 00:06:43,985 a world with as much land as Earth itself. 62 00:06:56,199 --> 00:06:59,501 A belt of rocky asteroids circles the Sun 63 00:06:59,535 --> 00:07:02,003 between the orbits of Mars and Jupiter. 64 00:07:13,516 --> 00:07:17,819 With its four giant moons and dozens of smaller ones, 65 00:07:17,854 --> 00:07:21,323 Jupiter is like its own little solar system. 66 00:07:21,357 --> 00:07:25,760 It has more mass than all the other planets combined. 67 00:07:35,404 --> 00:07:39,374 Jupiter's Great Red Spot... 68 00:07:39,408 --> 00:07:42,510 a hurricane three times the size of our whole planet 69 00:07:42,562 --> 00:07:46,214 that's been raging for centuries. 70 00:08:06,569 --> 00:08:10,438 The crown jewel of our solar system, Saturn, 71 00:08:10,473 --> 00:08:13,708 ringed by freeways of countless orbiting 72 00:08:13,743 --> 00:08:16,111 and slowly tumbling snowballs-- 73 00:08:16,145 --> 00:08:20,148 every snowball, a little moon. 74 00:08:50,780 --> 00:08:53,949 Uranus... 75 00:08:53,983 --> 00:08:55,951 and Neptune, 76 00:08:55,985 --> 00:09:00,288 the outermost planets, unknown to the ancients 77 00:09:00,356 --> 00:09:05,360 and only discovered after the invention of the telescope. 78 00:09:06,495 --> 00:09:08,863 Beyond the outermost planet, 79 00:09:08,898 --> 00:09:13,568 there's a swarm of tens of thousands of frozen worlds. 80 00:09:31,087 --> 00:09:33,722 And Pluto is one them. 81 00:09:39,996 --> 00:09:42,397 (whooshing) 82 00:09:46,402 --> 00:09:48,803 Of all our spacecraft, 83 00:09:48,838 --> 00:09:52,140 this is the one that's traveled farthest from home-- 84 00:09:52,207 --> 00:09:55,377 Voyager 1. 85 00:09:55,394 --> 00:10:00,048 She bears a message to a billion years from now, 86 00:10:00,082 --> 00:10:02,817 something of who we were, 87 00:10:02,852 --> 00:10:04,986 how we felt 88 00:10:05,021 --> 00:10:06,988 and the music we made. 89 00:10:07,023 --> 00:10:09,324 (Blind Willie Johnson's "Dark Was the Night" playing) 90 00:10:09,358 --> 00:10:11,760 (Blind Willie Johnson humming) 91 00:10:18,234 --> 00:10:20,068 DEGRASSE TYSON: The deeper waters 92 00:10:20,070 --> 00:10:21,936 of this vast cosmic ocean 93 00:10:21,971 --> 00:10:25,774 and their numberless worlds lie ahead. 94 00:10:25,841 --> 00:10:28,243 ("Dark Was the Night" continues to play, then fades) 95 00:10:37,970 --> 00:10:41,840 DEGRASSE TYSON: From out here, the Sun may look like just another star. 96 00:10:41,874 --> 00:10:44,275 But it still exerts its gravitational hold 97 00:10:44,310 --> 00:10:46,678 on a trillion frozen comets, 98 00:10:46,712 --> 00:10:49,447 leftovers from the formation of the solar system 99 00:10:49,482 --> 00:10:52,283 nearly five billion years ago. 100 00:10:52,318 --> 00:10:54,919 It's called the Oort Cloud. 101 00:10:54,954 --> 00:10:57,656 No one has ever seen it before, nor could they, 102 00:10:57,690 --> 00:10:59,924 because each one of these little worlds 103 00:10:59,992 --> 00:11:02,160 is as far from its nearest neighbor 104 00:11:02,194 --> 00:11:05,797 as Earth is from Saturn. 105 00:11:05,831 --> 00:11:09,634 This enormous cloud of comets encloses the solar system, 106 00:11:09,669 --> 00:11:13,471 which is the second line of our cosmic address. 107 00:11:18,377 --> 00:11:22,013 We've only been able to detect the planets of other stars 108 00:11:22,048 --> 00:11:24,015 for a few decades, 109 00:11:24,050 --> 00:11:27,786 but we already know that planets are plentiful-- 110 00:11:27,820 --> 00:11:30,455 they outnumber the stars. 111 00:11:30,489 --> 00:11:33,892 Almost all of them will be very different from Earth, 112 00:11:33,926 --> 00:11:36,394 and hostile to life as we know it. 113 00:11:36,429 --> 00:11:38,797 But what do we know about life? 114 00:11:38,831 --> 00:11:41,866 We've met only one kind so far: 115 00:11:41,901 --> 00:11:43,835 Earthlife. 116 00:11:43,869 --> 00:11:45,170 See anything? 117 00:11:45,204 --> 00:11:47,172 Just empty space, right? 118 00:11:47,206 --> 00:11:49,974 Human eyes see only a sliver of the light 119 00:11:50,009 --> 00:11:51,976 that shines in the cosmos. 120 00:11:52,011 --> 00:11:56,214 But science gives us the power to see what our senses cannot. 121 00:11:56,248 --> 00:11:58,983 Infrared is the kind of light made visible 122 00:11:59,051 --> 00:12:01,019 by night-vision goggles. 123 00:12:01,053 --> 00:12:03,688 Throw an infrared sensor across the darkness... 124 00:12:05,124 --> 00:12:06,725 Rogue planet. 125 00:12:06,759 --> 00:12:09,027 World without a sun. 126 00:12:10,930 --> 00:12:15,366 Our galaxy has billions of them, adrift in perpetual night. 127 00:12:15,401 --> 00:12:18,937 They're orphans, cast away from their mother stars 128 00:12:18,971 --> 00:12:22,407 during the chaotic birth of their native star systems. 129 00:12:24,076 --> 00:12:26,778 Rogue planets are molten at the core 130 00:12:26,812 --> 00:12:28,780 but frozen at the surface. 131 00:12:28,814 --> 00:12:30,782 There may be oceans of liquid water 132 00:12:30,816 --> 00:12:33,818 in the zone between those extremes. 133 00:12:38,390 --> 00:12:41,976 Who knows what might be swimming there? 134 00:12:46,766 --> 00:12:49,934 This is what the Milky Way looks like in infrared. 135 00:12:49,969 --> 00:12:53,037 Every single dot, not just the bright ones, 136 00:12:53,072 --> 00:12:55,240 is a star. 137 00:12:55,274 --> 00:12:57,242 How many stars? 138 00:12:57,276 --> 00:12:59,244 How many worlds? 139 00:12:59,278 --> 00:13:01,746 How many ways of being alive? 140 00:13:01,781 --> 00:13:04,749 Where are we in this picture? 141 00:13:04,784 --> 00:13:07,218 See that trailing outer arm? 142 00:13:07,253 --> 00:13:09,404 That's where we live-- 143 00:13:09,455 --> 00:13:12,657 about 30,000 light-years from the center. 144 00:13:12,691 --> 00:13:14,392 The Milky Way Galaxy 145 00:13:14,426 --> 00:13:17,729 is the next line of our cosmic address. 146 00:13:17,763 --> 00:13:20,131 We're now a hundred thousand light-years from home. 147 00:13:20,166 --> 00:13:23,401 It would take light, the fastest thing there is, 148 00:13:23,435 --> 00:13:27,305 a hundred thousand years to reach us from Earth. 149 00:13:30,042 --> 00:13:32,443 This is the Great Spiral in Andromeda, 150 00:13:32,478 --> 00:13:34,445 the galaxy next door. 151 00:13:34,480 --> 00:13:36,431 We call our two giant galaxies 152 00:13:36,482 --> 00:13:38,433 and a smattering of smaller ones 153 00:13:38,484 --> 00:13:40,819 the "local group." 154 00:13:48,494 --> 00:13:51,796 Can't even find our home galaxy from out here. 155 00:13:51,831 --> 00:13:55,967 It's just one of thousands in the Virgo Supercluster. 156 00:13:56,068 --> 00:13:57,969 On this scale, 157 00:13:58,003 --> 00:14:01,606 all the objects we see, including the tiniest dots, 158 00:14:01,640 --> 00:14:03,441 are galaxies. 159 00:14:03,475 --> 00:14:06,010 Each galaxy contains billions of suns 160 00:14:06,045 --> 00:14:08,112 and countless worlds. 161 00:14:08,147 --> 00:14:11,783 Yet, the entire Virgo Supercluster itself 162 00:14:11,817 --> 00:14:15,019 forms but a tiny part of our universe. 163 00:14:16,722 --> 00:14:20,692 This is the cosmos on the grandest scale we know-- 164 00:14:20,726 --> 00:14:24,028 a network of a hundred billion galaxies. 165 00:14:24,063 --> 00:14:27,498 It's the last line of our cosmic address... 166 00:14:27,533 --> 00:14:29,534 for now. 167 00:14:31,103 --> 00:14:32,570 Observable universe?! 168 00:14:32,605 --> 00:14:34,472 What does that mean? 169 00:14:34,506 --> 00:14:37,242 Even for us, in our Ship of the Imagination, 170 00:14:37,276 --> 00:14:40,879 there's a limit to how far we can see in space-time. 171 00:14:40,913 --> 00:14:43,314 It's our cosmic horizon. 172 00:14:43,349 --> 00:14:46,417 Beyond that horizon lie parts of the universe 173 00:14:46,452 --> 00:14:48,586 that are too far away. 174 00:14:48,621 --> 00:14:50,588 There hasn't been enough time 175 00:14:50,623 --> 00:14:53,691 in the 13.8 billion year history of the universe 176 00:14:53,709 --> 00:14:56,227 for their light to have reached us. 177 00:14:58,264 --> 00:15:01,666 Many of us suspect that all of this-- 178 00:15:01,700 --> 00:15:05,904 all the worlds, stars, galaxies and clusters 179 00:15:05,938 --> 00:15:08,339 in our observable universe-- 180 00:15:08,374 --> 00:15:13,077 is but one tiny bubble in an infinite ocean 181 00:15:13,112 --> 00:15:15,146 of other universes... 182 00:15:16,749 --> 00:15:19,217 ...a multiverse. 183 00:15:19,251 --> 00:15:23,021 Universe upon universe. 184 00:15:23,055 --> 00:15:25,623 Worlds without end. 185 00:15:30,329 --> 00:15:32,397 Feeling a little small? 186 00:15:32,431 --> 00:15:35,900 Well, in the context of the cosmos, we are small. 187 00:15:35,935 --> 00:15:39,237 We may just be little guys living on a speck of dust, 188 00:15:39,271 --> 00:15:41,639 afloat in a staggering immensity, 189 00:15:41,674 --> 00:15:43,775 but we don't think small. 190 00:15:43,809 --> 00:15:47,245 This cosmic perspective is relatively new. 191 00:15:47,279 --> 00:15:51,549 A mere four centuries ago, our tiny world was oblivious 192 00:15:51,583 --> 00:15:53,551 to the rest of the cosmos. 193 00:15:53,585 --> 00:15:55,553 There were no telescopes. 194 00:15:55,587 --> 00:15:59,324 The universe was only what you could see with the naked eye. 195 00:15:59,358 --> 00:16:01,426 Back in 1599, 196 00:16:01,460 --> 00:16:04,796 everyone knew that the Sun, planets and stars 197 00:16:04,830 --> 00:16:08,833 were just lights in the sky that revolved around the Earth, 198 00:16:08,867 --> 00:16:12,904 and that we were the center of a little universe, 199 00:16:12,938 --> 00:16:15,707 a universe made for us. 200 00:16:17,276 --> 00:16:19,644 There was only one man on the whole planet 201 00:16:19,678 --> 00:16:22,513 who envisioned an infinitely grander cosmos. 202 00:16:22,548 --> 00:16:25,083 And how was he spending New Year's Eve 203 00:16:25,117 --> 00:16:28,252 of the year 1600? 204 00:16:28,287 --> 00:16:31,122 Why, in prison, of course. 205 00:16:37,579 --> 00:16:39,747 DEGRASSE TYSON: There comes a time in our lives 206 00:16:39,782 --> 00:16:43,017 when we first realize we're not the center of the universe, 207 00:16:43,052 --> 00:16:46,254 that we belong to something much greater than ourselves. 208 00:16:46,288 --> 00:16:48,256 It's part of growing up. 209 00:16:48,290 --> 00:16:50,525 And as it happens to each of us, 210 00:16:50,559 --> 00:16:52,860 so it began to happen to our civilization 211 00:16:52,895 --> 00:16:54,862 in the 16th century. 212 00:16:54,880 --> 00:16:56,764 Imagine a world before telescopes, 213 00:16:56,799 --> 00:16:59,033 when the universe was only what you could see 214 00:16:59,068 --> 00:17:00,568 with the naked eye. 215 00:17:00,602 --> 00:17:03,771 It was obvious that Earth was motionless, 216 00:17:03,806 --> 00:17:05,506 and that everything in the heavens-- 217 00:17:05,541 --> 00:17:07,842 the Sun, the Moon, the stars, the planets-- 218 00:17:07,876 --> 00:17:10,712 revolved around us-- and then... 219 00:17:10,746 --> 00:17:13,014 a Polish astronomer and priest named Copernicus 220 00:17:13,048 --> 00:17:17,018 made a radical proposal: The Earth was not the center. 221 00:17:17,052 --> 00:17:19,520 It was just one of the planets, and, like them, 222 00:17:19,555 --> 00:17:21,522 it revolved around the Sun. 223 00:17:21,557 --> 00:17:24,859 Many, like the Protestant reformer Martin Luther, 224 00:17:24,893 --> 00:17:27,862 took this idea as a scandalous affront to Scripture. 225 00:17:27,896 --> 00:17:30,131 They were horrified. 226 00:17:30,165 --> 00:17:34,602 But for one man, Copernicus didn't go far enough. 227 00:17:34,636 --> 00:17:37,739 His name was Giordano Bruno, 228 00:17:37,773 --> 00:17:40,241 and he was a natural-born rebel. 229 00:17:40,275 --> 00:17:43,444 He longed to bust out of that cramped little universe. 230 00:17:43,479 --> 00:17:45,913 Even as a young Dominican monk in Naples, 231 00:17:45,948 --> 00:17:48,116 he was a misfit. This was a time 232 00:17:48,150 --> 00:17:50,451 when there was no freedom of thought in Italy. 233 00:17:50,486 --> 00:17:51,886 But Bruno hungered to know 234 00:17:51,920 --> 00:17:53,721 everything about God's creation. 235 00:17:53,756 --> 00:17:56,491 He dared to read the books banned by the Church, 236 00:17:56,525 --> 00:17:58,292 and that was his undoing. 237 00:17:58,327 --> 00:18:00,261 In one of them, 238 00:18:00,345 --> 00:18:04,449 an ancient Roman, a man dead for more than 1,500 years 239 00:18:04,500 --> 00:18:07,435 whispered to him of a universe far greater, 240 00:18:07,469 --> 00:18:10,471 one as boundless as his idea of God. 241 00:18:14,610 --> 00:18:16,577 Lucretius asked the reader 242 00:18:16,612 --> 00:18:18,980 to imagine standing at the edge of the universe 243 00:18:19,014 --> 00:18:20,965 and shooting an arrow outward. 244 00:18:21,016 --> 00:18:23,284 If the arrow keeps going, then clearly, 245 00:18:23,318 --> 00:18:26,187 the universe extends beyond what you thought was the edge. 246 00:18:26,221 --> 00:18:28,623 But if the arrow doesn't keep going-- 247 00:18:28,657 --> 00:18:31,325 say it hits a wall-- then that wall must lie 248 00:18:31,360 --> 00:18:34,295 beyond what you thought was the edge of the universe. 249 00:18:34,329 --> 00:18:37,632 Now if you stand on that wall and shoot another arrow, 250 00:18:37,666 --> 00:18:40,368 there are only the same two possible outcomes: 251 00:18:40,402 --> 00:18:42,703 it either flies forever out into space, 252 00:18:42,805 --> 00:18:44,772 or it hits some boundary 253 00:18:44,807 --> 00:18:47,542 where you can stand and shoot yet another arrow. 254 00:18:47,576 --> 00:18:50,144 Either way, the universe is unbounded. 255 00:18:50,179 --> 00:18:53,447 The cosmos must be infinite. 256 00:18:53,482 --> 00:18:55,950 This made perfect sense to Bruno. 257 00:18:55,984 --> 00:18:58,319 The God he worshipped was infinite. 258 00:18:58,353 --> 00:19:02,190 So how, he reasoned, could Creation be anything less? 259 00:19:02,224 --> 00:19:03,558 (door opens) 260 00:19:12,201 --> 00:19:13,201 (door opens) 261 00:19:17,840 --> 00:19:20,675 It was the last steady job he ever had. 262 00:19:24,680 --> 00:19:26,881 (wind whistles softly) 263 00:19:30,085 --> 00:19:32,486 And then, when he was 30, 264 00:19:32,521 --> 00:19:36,157 he had the vision that sealed his fate. 265 00:19:36,191 --> 00:19:38,659 In this dream, he awakened to a world 266 00:19:38,694 --> 00:19:41,729 enclosed inside a confining bowl of stars. 267 00:19:41,763 --> 00:19:44,765 This was the cosmos of Bruno's time. 268 00:20:03,218 --> 00:20:05,786 He experienced a sickening moment of fear, 269 00:20:05,788 --> 00:20:07,288 as if the bottom of everything 270 00:20:07,322 --> 00:20:09,924 was falling away beneath his feet. 271 00:20:09,926 --> 00:20:12,426 But he summoned up his courage. 272 00:20:20,469 --> 00:20:23,271 BRUNO: I spread confident wings to space 273 00:20:23,305 --> 00:20:26,874 and soared toward the infinite, leaving far behind me 274 00:20:26,909 --> 00:20:30,244 what others strained to see from a distance. 275 00:20:30,279 --> 00:20:33,648 Here, there was no up, no down, no edge, 276 00:20:33,715 --> 00:20:35,216 no center. 277 00:20:35,250 --> 00:20:38,653 I saw that the Sun was just another star, 278 00:20:38,687 --> 00:20:42,623 and the stars were other Suns, each escorted by other Earths 279 00:20:42,658 --> 00:20:44,258 like our own. 280 00:20:44,293 --> 00:20:47,561 The revelation of this immensity was like 281 00:20:47,596 --> 00:20:49,030 falling in love. 282 00:20:52,501 --> 00:20:54,468 DEGRASSE TYSON: Bruno became an evangelist, 283 00:20:54,503 --> 00:20:57,938 spreading the gospel of infinity throughout Europe. 284 00:20:57,940 --> 00:21:01,509 He assumed that other lovers of God would naturally embrace 285 00:21:01,526 --> 00:21:04,578 this grander and more glorious view of Creation. 286 00:21:04,646 --> 00:21:07,648 BRUNO: What a fool I was. 287 00:21:09,685 --> 00:21:11,352 DEGRASSE TYSON: He was excommunicated 288 00:21:11,386 --> 00:21:13,287 by the Roman Catholic Church in his homeland, 289 00:21:13,355 --> 00:21:15,756 expelled by the Calvinists in Switzerland, 290 00:21:15,791 --> 00:21:17,992 and by the Lutherans in Germany. 291 00:21:17,994 --> 00:21:21,028 Bruno jumped at an invitation 292 00:21:21,063 --> 00:21:23,898 to lecture at Oxford, in England. 293 00:21:25,300 --> 00:21:27,134 At last, he thought, 294 00:21:27,169 --> 00:21:30,805 a chance to share his vision with an audience of his peers. 295 00:21:30,839 --> 00:21:32,957 (laughter) 296 00:21:33,008 --> 00:21:34,875 (laughter continues) 297 00:21:34,910 --> 00:21:37,962 I have come to present a new vision of the cosmos. 298 00:21:38,013 --> 00:21:41,048 Copernicus was right to argue that our world 299 00:21:41,066 --> 00:21:42,783 is not the center of the universe. 300 00:21:42,818 --> 00:21:44,852 The Earth goes around the Sun. 301 00:21:44,886 --> 00:21:47,355 It's a planet, just like the others. 302 00:21:47,389 --> 00:21:49,457 But Copernicus was only the dawn. 303 00:21:49,491 --> 00:21:51,659 I bring you the sunrise. 304 00:21:53,061 --> 00:21:55,129 The stars are other fiery suns, 305 00:21:55,131 --> 00:21:57,365 made of the same substance as the Earth, 306 00:21:57,399 --> 00:22:00,401 and they have their own watery earths, 307 00:22:00,435 --> 00:22:03,504 with plants and animals no less noble than our own. 308 00:22:03,538 --> 00:22:05,806 Are you mad or merely ignorant? 309 00:22:05,841 --> 00:22:07,575 Everyone knows there is only one world. 310 00:22:07,609 --> 00:22:10,077 What everyone knows is wrong. 311 00:22:10,112 --> 00:22:13,080 Our infinite God has created a boundless universe 312 00:22:13,115 --> 00:22:14,982 with an infinite number of worlds. 313 00:22:15,017 --> 00:22:17,018 Do they not read Aristotle where you come from? 314 00:22:17,052 --> 00:22:18,753 Or even the Bible? 315 00:22:18,787 --> 00:22:23,391 I beg you, reject antiquity, tradition, faith, and authority. 316 00:22:23,425 --> 00:22:24,692 Let us begin anew, 317 00:22:24,726 --> 00:22:26,727 by doubting everything we assume 318 00:22:26,762 --> 00:22:27,862 has been proven. Heretic! 319 00:22:27,896 --> 00:22:28,929 Infidel! 320 00:22:28,964 --> 00:22:30,831 Your God is too small. 321 00:22:30,866 --> 00:22:32,867 (scholars shouting angrily) 322 00:22:35,404 --> 00:22:38,773 DEGRASSE TYSON: A wiser man would have learned his lesson. 323 00:22:38,807 --> 00:22:42,109 But Bruno was not such a man. 324 00:22:42,144 --> 00:22:46,380 He couldn't keep his soaring vision of the cosmos to himself, 325 00:22:46,415 --> 00:22:49,350 despite the fact that the penalty for doing so 326 00:22:49,384 --> 00:22:52,386 in his world was the most vicious form 327 00:22:52,421 --> 00:22:54,422 of cruel and unusual punishment. 328 00:22:58,276 --> 00:23:00,945 time when there was no such thing 329 00:23:00,979 --> 00:23:02,913 as the separation of church and state, 330 00:23:02,948 --> 00:23:05,483 or the notion that freedom of speech was a sacred right 331 00:23:05,517 --> 00:23:07,451 of every individual. 332 00:23:07,486 --> 00:23:10,321 Expressing an idea that didn't conform to traditional belief 333 00:23:10,355 --> 00:23:12,957 could land you in deep trouble. 334 00:23:14,960 --> 00:23:17,628 Recklessly, Bruno returned to Italy. 335 00:23:17,662 --> 00:23:19,296 Maybe he was homesick. 336 00:23:19,331 --> 00:23:22,566 But still, he must have known that his homeland 337 00:23:22,601 --> 00:23:24,668 was one of the most dangerous places in Europe 338 00:23:24,703 --> 00:23:26,437 he could possibly go. 339 00:23:26,471 --> 00:23:29,507 The Roman Catholic Church maintained a system of courts 340 00:23:29,541 --> 00:23:31,342 known as the Inquisition, 341 00:23:31,376 --> 00:23:34,912 and its sole purpose was to investigate and torment 342 00:23:34,946 --> 00:23:38,816 anyone who dared voice views that differed from theirs. 343 00:23:41,853 --> 00:23:45,790 It wasn't long before Bruno fell into the clutches 344 00:23:45,824 --> 00:23:47,691 of the thought police. 345 00:23:53,732 --> 00:23:56,367 This wanderer, who worshipped an infinite universe, 346 00:23:56,401 --> 00:23:59,537 languished in confinement for eight years. 347 00:23:59,571 --> 00:24:01,372 Through relentless interrogations, 348 00:24:01,406 --> 00:24:04,108 he stubbornly refused to renounce his views. 349 00:24:04,175 --> 00:24:05,676 Why was the Church willing 350 00:24:05,710 --> 00:24:09,380 to go to such lengths to torment Bruno? 351 00:24:09,414 --> 00:24:11,449 What were they afraid of? 352 00:24:11,483 --> 00:24:14,685 If Bruno was right, then the sacred books 353 00:24:14,719 --> 00:24:16,854 and the authority of the Church 354 00:24:16,888 --> 00:24:20,224 would be open to question. 355 00:24:20,258 --> 00:24:21,959 Finally, the cardinals of the Inquisition 356 00:24:21,993 --> 00:24:23,894 rendered their verdict. 357 00:24:23,929 --> 00:24:25,496 CARDINAL BELLARMINE: You are found guilty 358 00:24:25,530 --> 00:24:28,365 of questioning the Holy Trinity 359 00:24:28,400 --> 00:24:31,068 and the divinity of Jesus Christ. 360 00:24:31,102 --> 00:24:34,371 Of believing that God's wrath is not eternal, 361 00:24:34,406 --> 00:24:35,873 that everyone will be saved. 362 00:24:35,907 --> 00:24:40,711 Of asserting the existence of other worlds. 363 00:24:41,847 --> 00:24:44,748 All of the books you have written 364 00:24:44,816 --> 00:24:48,252 will be gathered up and burned in St. Peter's Square. 365 00:24:48,319 --> 00:24:51,856 Reverend Father, these eight years of confinement 366 00:24:51,890 --> 00:24:53,424 have given me much time to reflect. 367 00:24:53,458 --> 00:24:54,425 CARDINAL BELLARMINE: So... 368 00:24:54,459 --> 00:24:55,826 you will recant? 369 00:24:55,861 --> 00:24:57,828 My love and reverence for the Creator 370 00:24:57,863 --> 00:25:01,499 inspires in me the vision of an infinite Creation. 371 00:25:01,533 --> 00:25:05,102 You shall be turned over to the Governor of Rome 372 00:25:05,136 --> 00:25:08,506 to administer the appropriate punishment 373 00:25:08,540 --> 00:25:10,608 for those who will not repent. 374 00:25:10,642 --> 00:25:12,676 (crowd jeers) 375 00:25:12,711 --> 00:25:16,614 It may be that you are more afraid 376 00:25:16,648 --> 00:25:19,984 to deliver this judgment than I am to hear it. 377 00:25:52,250 --> 00:25:55,152 (crowd shouting) 378 00:26:28,119 --> 00:26:30,354 Ten years after Bruno's martyrdom, 379 00:26:30,388 --> 00:26:32,823 Galileo first looked through a telescope, 380 00:26:32,857 --> 00:26:35,492 realizing that Bruno had been right all along. 381 00:26:35,527 --> 00:26:38,262 The Milky Way was made of countless stars 382 00:26:38,296 --> 00:26:39,997 invisible to the naked eye, 383 00:26:40,031 --> 00:26:43,968 and some of those lights in the sky were actually other worlds. 384 00:26:44,002 --> 00:26:46,270 Bruno was no scientist. 385 00:26:46,304 --> 00:26:48,772 His vision of the cosmos was a lucky guess, 386 00:26:48,807 --> 00:26:51,275 because he had no evidence to support it. 387 00:26:51,309 --> 00:26:54,545 Like most guesses, it could well have turned out wrong. 388 00:26:54,579 --> 00:26:57,147 But once the idea was in the air, 389 00:26:57,182 --> 00:26:59,216 it gave others a target to aim at. 390 00:26:59,250 --> 00:27:00,851 If only to disprove it. 391 00:27:02,887 --> 00:27:06,557 Bruno glimpsed the vastness of space. 392 00:27:06,591 --> 00:27:11,362 But he had no inkling of the staggering immensity of time. 393 00:27:14,933 --> 00:27:18,002 How can we humans, who rarely live more than a century, 394 00:27:18,036 --> 00:27:20,804 hope to grasp the vast expanse of time 395 00:27:20,839 --> 00:27:23,040 that is the history of the cosmos? 396 00:27:23,074 --> 00:27:27,845 The universe is 13.8 thousand million years old. 397 00:27:27,879 --> 00:27:30,180 In order to imagine all of cosmic time, 398 00:27:30,281 --> 00:27:33,917 let's compress it into a single calendar year. 399 00:27:46,064 --> 00:27:48,265 Cosmic Calendar begins on January 1, 400 00:27:48,299 --> 00:27:50,267 with the birth of our universe. 401 00:27:50,301 --> 00:27:54,104 It contains everything that's happened since then up to now, 402 00:27:54,139 --> 00:27:58,342 which on this calendar is midnight, December 31. 403 00:27:58,376 --> 00:28:00,744 On this scale, every month 404 00:28:00,779 --> 00:28:02,780 represents about a billion years. 405 00:28:02,814 --> 00:28:06,950 Every day represents nearly 40 million years. 406 00:28:06,985 --> 00:28:09,086 Let's go back as far as we can, 407 00:28:09,120 --> 00:28:12,790 to the very first moment of the universe. 408 00:28:12,824 --> 00:28:14,758 January 1. 409 00:28:14,793 --> 00:28:16,727 The Big Bang. 410 00:28:26,604 --> 00:28:31,075 It's as far back as we can see in time... 411 00:28:31,109 --> 00:28:33,110 for now. 412 00:28:34,646 --> 00:28:36,814 Our entire universe emerged 413 00:28:36,848 --> 00:28:39,550 from a point smaller than a single atom. 414 00:28:39,584 --> 00:28:42,553 Space itself exploded in a cosmic fire, 415 00:28:42,587 --> 00:28:44,922 launching the expansion of the universe 416 00:28:44,956 --> 00:28:47,324 and giving birth to all the energy 417 00:28:47,358 --> 00:28:49,293 and all the matter we know today. 418 00:28:49,327 --> 00:28:51,628 I know that sounds crazy, 419 00:28:51,663 --> 00:28:53,597 but there's strong observational evidence 420 00:28:53,631 --> 00:28:55,232 to support the Big Bang theory. 421 00:28:55,266 --> 00:28:57,735 And it includes the amount of helium in the cosmos 422 00:28:57,752 --> 00:29:01,405 and the glow of radio waves left over from the explosion. 423 00:29:01,439 --> 00:29:03,907 As it expanded, the universe cooled, 424 00:29:03,942 --> 00:29:08,812 and there was darkness for about 200 million years. 425 00:29:08,847 --> 00:29:11,782 Gravity was pulling together clumps of gas and heating them 426 00:29:11,816 --> 00:29:14,785 until the first stars burst into light 427 00:29:14,819 --> 00:29:17,020 on January 10. 428 00:29:21,960 --> 00:29:25,763 On January 13, these stars coalesced 429 00:29:25,797 --> 00:29:30,667 into the first small galaxies. 430 00:29:30,702 --> 00:29:33,504 These galaxies merged to form still larger ones, 431 00:29:33,538 --> 00:29:36,874 including our own Milky Way, 432 00:29:36,908 --> 00:29:41,345 which formed about 11 billion years ago, 433 00:29:41,379 --> 00:29:44,214 on March 15 of the cosmic year. 434 00:29:46,084 --> 00:29:48,552 Hundreds of billions of suns. 435 00:29:48,586 --> 00:29:50,387 Which one is ours? 436 00:29:50,421 --> 00:29:52,623 It's not yet born. 437 00:29:52,657 --> 00:29:57,127 It will rise from the ashes of other stars. 438 00:29:57,162 --> 00:30:00,364 See those lights flashing like paparazzi? 439 00:30:00,398 --> 00:30:02,833 Each one is a supernova, 440 00:30:02,867 --> 00:30:06,036 the blazing death of a giant star. 441 00:30:06,038 --> 00:30:09,406 Stars die and are born in places like this one-- 442 00:30:09,440 --> 00:30:11,308 a stellar nursery. 443 00:30:11,342 --> 00:30:13,010 They condense like raindrops 444 00:30:13,044 --> 00:30:15,679 from giant clouds of gas and dust. 445 00:30:15,713 --> 00:30:18,682 They get so hot that the nuclei of the atoms 446 00:30:18,716 --> 00:30:21,218 fuse together deep within them 447 00:30:21,252 --> 00:30:24,421 to make the oxygen we breathe, the carbon in our muscles, 448 00:30:24,455 --> 00:30:27,891 the calcium in our bones, the iron in our blood, 449 00:30:27,926 --> 00:30:29,693 all of it was cooked 450 00:30:29,727 --> 00:30:33,197 in the fiery hearts of long-vanished stars. 451 00:30:33,231 --> 00:30:36,934 You, me, everyone-- 452 00:30:36,968 --> 00:30:41,405 we are made of star stuff. 453 00:30:43,208 --> 00:30:45,509 This star stuff is recycled and enriched, 454 00:30:45,543 --> 00:30:47,077 again and again, 455 00:30:47,111 --> 00:30:49,780 through succeeding generations of stars. 456 00:30:54,052 --> 00:30:56,420 How much longer until the birth of our Sun? 457 00:30:56,454 --> 00:30:58,222 A long time. 458 00:30:58,256 --> 00:30:59,523 It won't begin to shine 459 00:30:59,557 --> 00:31:02,392 for another six billion years. 460 00:31:04,095 --> 00:31:07,064 Our Sun's birthday is August 31 461 00:31:07,098 --> 00:31:08,899 on the Cosmic Calendar... 462 00:31:11,436 --> 00:31:13,704 ...four and a half billion years ago. 463 00:31:13,738 --> 00:31:16,206 As with the other worlds of our solar system, 464 00:31:16,241 --> 00:31:19,309 Earth was formed from a disk of gas and dust 465 00:31:19,344 --> 00:31:21,478 orbiting the newborn Sun. 466 00:31:21,512 --> 00:31:24,948 Repeated collisions produced a growing ball of debris. 467 00:31:31,356 --> 00:31:32,756 See that asteroid? 468 00:31:32,790 --> 00:31:34,091 No, not that one. 469 00:31:34,125 --> 00:31:35,792 The one over there. 470 00:31:35,827 --> 00:31:39,563 We exist because the gravity of that one next to it 471 00:31:39,597 --> 00:31:42,733 just nudged it an inch to the left. 472 00:31:42,767 --> 00:31:44,768 What difference could an inch make 473 00:31:44,802 --> 00:31:46,837 on the scale the solar system? 474 00:31:46,871 --> 00:31:49,773 Just wait, you'll see. 475 00:31:51,342 --> 00:31:53,126 The Earth took one hell of a beating 476 00:31:53,177 --> 00:31:55,012 in its first billion years. 477 00:31:58,449 --> 00:32:01,318 Fragments of orbiting debris collided and coalesced, 478 00:32:01,352 --> 00:32:03,954 until they snowballed to form our Moon. 479 00:32:06,124 --> 00:32:09,660 The Moon is a souvenir of that violent epoch. 480 00:32:09,694 --> 00:32:12,696 If you stood on the surface of that long ago Earth, 481 00:32:12,730 --> 00:32:15,432 the Moon would have looked a hundred times brighter. 482 00:32:15,450 --> 00:32:17,634 It was ten times closer back then, 483 00:32:17,669 --> 00:32:22,372 locked in a much more intimate gravitational embrace. 484 00:32:22,407 --> 00:32:25,342 As the Earth cooled, seas began to form. 485 00:32:25,376 --> 00:32:28,445 The tides were a thousand times higher then. 486 00:32:28,479 --> 00:32:31,682 Over the eons, tidal friction within Earth 487 00:32:31,716 --> 00:32:33,817 pushed the Moon away. 488 00:32:39,691 --> 00:32:42,392 Life began somewhere around here, 489 00:32:42,427 --> 00:32:44,494 September 21, 490 00:32:44,529 --> 00:32:47,564 three and a half billion years ago on our little world. 491 00:32:47,598 --> 00:32:49,366 We still don't know how life got started. 492 00:32:49,400 --> 00:32:51,034 For all we know, 493 00:32:51,069 --> 00:32:53,070 it may have come from another part of the Milky Way. 494 00:32:53,104 --> 00:32:54,905 The origin of life 495 00:32:54,939 --> 00:32:58,108 is one of the greatest unsolved mysteries of science. 496 00:33:01,779 --> 00:33:03,814 That's life cooking, 497 00:33:03,848 --> 00:33:06,383 evolving all the biochemical recipes 498 00:33:06,417 --> 00:33:10,020 for its incredibly complex activities. 499 00:33:10,121 --> 00:33:15,659 By November 9, life was breathing, moving, 500 00:33:15,693 --> 00:33:19,563 eating, responding to its environment. 501 00:33:19,597 --> 00:33:22,499 We owe a lot to those pioneering microbes. 502 00:33:22,533 --> 00:33:24,568 Oh, yeah-- one other thing. 503 00:33:24,602 --> 00:33:27,938 They also invented sex. 504 00:33:31,376 --> 00:33:33,543 December 17 was quite a day. 505 00:33:33,578 --> 00:33:36,013 Life in the sea really took off, 506 00:33:36,047 --> 00:33:38,181 it was exploding with a diversity 507 00:33:38,216 --> 00:33:40,183 of larger plants and animals. 508 00:33:40,218 --> 00:33:45,322 Tiktaalik was one of the first animals to venture onto land. 509 00:33:47,225 --> 00:33:50,594 It must have felt like visiting another planet. 510 00:33:52,096 --> 00:33:54,464 Forests, dinosaurs, 511 00:33:54,499 --> 00:33:56,800 birds, insects, 512 00:33:56,834 --> 00:34:00,203 they all evolved in the final week of December. 513 00:34:00,238 --> 00:34:02,072 The first flower... 514 00:34:02,106 --> 00:34:06,410 bloomed on December 28. 515 00:34:09,814 --> 00:34:12,549 As these ancient forests grew and died 516 00:34:12,583 --> 00:34:14,551 and sank beneath the surface, 517 00:34:14,585 --> 00:34:17,421 their remains transformed into coal. 518 00:34:17,455 --> 00:34:20,057 300 million years later, 519 00:34:20,091 --> 00:34:23,393 we humans are burning most of that coal to power 520 00:34:23,428 --> 00:34:26,496 and imperil our civilization. 521 00:34:26,531 --> 00:34:28,932 (whooshing) 522 00:34:31,469 --> 00:34:32,836 Remember that asteroid back in the formation 523 00:34:32,870 --> 00:34:34,504 of the solar system-- 524 00:34:34,539 --> 00:34:36,673 the one that got nudged a little to the left? 525 00:34:36,707 --> 00:34:39,009 Well, here it comes. 526 00:34:39,043 --> 00:34:41,478 It's 6:24 a.m. 527 00:34:41,512 --> 00:34:45,816 on December 30 on the Cosmic Calendar. 528 00:34:45,850 --> 00:34:47,317 (impact thundering) 529 00:34:52,824 --> 00:34:54,758 For more than a hundred million years, 530 00:34:54,760 --> 00:34:56,993 the dinosaurs were lords of the Earth, 531 00:34:57,028 --> 00:34:59,763 while our ancestors, small mammals, 532 00:34:59,797 --> 00:35:01,932 scurried fearfully underfoot. 533 00:35:01,966 --> 00:35:04,334 The asteroid changed all that. 534 00:35:04,368 --> 00:35:06,169 Suppose it hadn't been nudged at all. 535 00:35:06,204 --> 00:35:08,004 It would have missed the Earth entirely, 536 00:35:08,039 --> 00:35:10,307 and for all we know, the dinosaurs might still be here 537 00:35:10,341 --> 00:35:11,942 but we wouldn't. 538 00:35:11,976 --> 00:35:14,945 This is a good example of the extreme contingency, 539 00:35:14,979 --> 00:35:17,714 the chance nature, of existence. 540 00:35:19,383 --> 00:35:22,652 The universe is already more than 13 and a half 541 00:35:22,687 --> 00:35:24,054 billion years old. 542 00:35:24,088 --> 00:35:25,889 Still no sign of us. 543 00:35:25,923 --> 00:35:30,060 In the vast ocean of time that this calendar represents, 544 00:35:30,094 --> 00:35:33,163 we humans only evolved within the last hour 545 00:35:33,197 --> 00:35:38,201 of the last day of the cosmic year. 546 00:35:43,574 --> 00:35:47,310 11:59 and 46 seconds. 547 00:35:47,312 --> 00:35:51,548 All of recorded history occupies only the last 14 seconds, 548 00:35:51,582 --> 00:35:54,317 and every person you've ever heard of 549 00:35:54,352 --> 00:35:56,353 lived somewhere in there. 550 00:35:58,222 --> 00:36:02,192 All those kings and battles, migrations and inventions, 551 00:36:02,194 --> 00:36:06,663 wars and loves, everything in the history books 552 00:36:06,697 --> 00:36:08,732 happened here, in the last seconds 553 00:36:08,766 --> 00:36:10,834 of the Cosmic Calendar. 554 00:36:10,868 --> 00:36:13,036 But if we want to explore 555 00:36:13,070 --> 00:36:15,605 such a brief moment of cosmic time... 556 00:36:18,242 --> 00:36:20,310 ...we'll have to change scale. 557 00:36:37,528 --> 00:36:39,963 We are newcomers to the cosmos. 558 00:36:39,997 --> 00:36:44,401 Our own story only begins on the last night of the cosmic year. 559 00:36:44,435 --> 00:36:47,804 It's 9:45 on New Year's Eve. 560 00:36:47,838 --> 00:36:50,240 Three and a half million years ago, 561 00:36:50,274 --> 00:36:54,177 our ancestors, yours and mine, left these traces. 562 00:36:55,546 --> 00:36:59,182 We stood up, and parted ways from them. 563 00:36:59,217 --> 00:37:01,117 Once we were standing on two feet, 564 00:37:01,152 --> 00:37:04,287 our eyes were no longer fixated on the ground. 565 00:37:04,322 --> 00:37:07,958 Now we were free to look up in wonder. 566 00:37:10,561 --> 00:37:13,029 For the longest part of human existence, 567 00:37:13,064 --> 00:37:16,800 say the last 40,000 generations, 568 00:37:16,834 --> 00:37:18,635 we were wanderers, 569 00:37:18,669 --> 00:37:21,838 living in small bands of hunters and gatherers, 570 00:37:21,872 --> 00:37:24,507 making tools, controlling fire, 571 00:37:24,542 --> 00:37:26,509 naming things, 572 00:37:26,544 --> 00:37:30,880 all within the last hour of the Cosmic Calendar. 573 00:37:39,023 --> 00:37:42,492 To find out what happens next, we'll have to change scale 574 00:37:42,526 --> 00:37:45,695 to see the last minute of the last night 575 00:37:45,730 --> 00:37:48,732 of the cosmic year. 576 00:37:48,766 --> 00:37:50,734 11:59. 577 00:37:50,768 --> 00:37:53,403 We're so very young on the time scale of the universe 578 00:37:53,437 --> 00:37:56,039 that we didn't start painting our first pictures 579 00:37:56,073 --> 00:37:59,643 until the last 60 seconds of the cosmic year, 580 00:37:59,677 --> 00:38:03,179 a mere 30,000 years ago. 581 00:38:11,422 --> 00:38:13,990 This is when we invented astronomy. 582 00:38:14,025 --> 00:38:17,226 In fact, we're all descended from astronomers. 583 00:38:17,228 --> 00:38:20,597 Our survival depended on knowing how to read the stars 584 00:38:20,631 --> 00:38:22,932 in order to predict the coming of the winter 585 00:38:22,967 --> 00:38:25,568 and the migration of the wild herds. 586 00:38:25,603 --> 00:38:28,571 And then, around 10,000 years ago, 587 00:38:28,606 --> 00:38:31,574 there began a revolution in the way we lived. 588 00:38:31,609 --> 00:38:34,844 Our ancestors learned how to shape their environment, 589 00:38:34,879 --> 00:38:37,247 taming wild plants and animals, 590 00:38:37,281 --> 00:38:40,250 cultivating land and settling down. 591 00:38:40,284 --> 00:38:42,852 This changed everything. 592 00:38:42,887 --> 00:38:44,854 For the first time in our history, 593 00:38:44,889 --> 00:38:48,258 we had more stuff than we could carry. 594 00:38:48,292 --> 00:38:50,694 We needed a way to keep track of it. 595 00:38:50,728 --> 00:38:52,896 At 14 seconds to midnight, 596 00:38:52,930 --> 00:38:56,399 or about 6,000 years ago, we invented writing. 597 00:38:56,434 --> 00:38:58,902 And it wasn't long before we started recording 598 00:38:58,936 --> 00:39:00,637 more than bushels of grain. 599 00:39:00,671 --> 00:39:02,639 Writing allowed us to save our thoughts 600 00:39:02,673 --> 00:39:05,909 and send them much further in space and time. 601 00:39:05,943 --> 00:39:08,311 Tiny markings on a clay tablet 602 00:39:08,346 --> 00:39:11,581 became a means for us to vanquish mortality. 603 00:39:11,615 --> 00:39:14,718 It shook the world. 604 00:39:14,752 --> 00:39:17,821 Moses was born seven seconds ago. 605 00:39:17,823 --> 00:39:20,757 Buddha, six seconds ago. 606 00:39:20,791 --> 00:39:23,660 Jesus, five seconds ago. 607 00:39:23,694 --> 00:39:27,097 Mohammed, three seconds ago. 608 00:39:27,131 --> 00:39:30,500 It was not even two seconds ago that, for better or worse, 609 00:39:30,534 --> 00:39:33,837 the two halves of the Earth discovered each other. 610 00:39:33,871 --> 00:39:36,106 And it was only in the very last second 611 00:39:36,140 --> 00:39:39,109 of the Cosmic Calendar that we began to use science 612 00:39:39,143 --> 00:39:42,278 to reveal nature's secrets and her laws. 613 00:39:42,296 --> 00:39:45,014 The scientific method is so powerful 614 00:39:45,049 --> 00:39:47,016 that in a mere four centuries, 615 00:39:47,051 --> 00:39:50,353 it has taken us from Galileo's first look through a telescope 616 00:39:50,355 --> 00:39:53,857 at another world to leaving our footprints on the Moon. 617 00:39:53,891 --> 00:39:58,361 It allowed us to look out across space and time 618 00:39:58,396 --> 00:40:04,134 to discover where and when we are in the cosmos. 619 00:40:04,168 --> 00:40:08,705 SAGAN: We are a way for the cosmos to know itself. 620 00:40:08,739 --> 00:40:11,040 Carl Sagan guided the maiden voyage of Cosmos 621 00:40:11,075 --> 00:40:12,809 a generation ago. 622 00:40:12,843 --> 00:40:15,011 He was the most successful science communicator 623 00:40:15,045 --> 00:40:16,513 of the 20th century, 624 00:40:16,547 --> 00:40:19,282 but he was first and foremost a scientist. 625 00:40:19,316 --> 00:40:22,819 Carl contributed enormously 626 00:40:22,837 --> 00:40:25,054 to our knowledge of the planets. 627 00:40:25,056 --> 00:40:28,057 He correctly predicted the existence of methane lakes 628 00:40:28,059 --> 00:40:30,026 on Saturn's giant moon Titan. 629 00:40:30,044 --> 00:40:33,329 He showed that the atmosphere of the early Earth 630 00:40:33,364 --> 00:40:36,299 must have contained powerful greenhouse gases. 631 00:40:36,333 --> 00:40:40,303 He was the first to understand that seasonal changes on Mars 632 00:40:40,370 --> 00:40:42,806 were due to windblown dust. 633 00:40:42,840 --> 00:40:44,374 Carl was a pioneer 634 00:40:44,408 --> 00:40:45,809 in the search for extraterrestrial life 635 00:40:45,843 --> 00:40:48,711 and intelligence. 636 00:40:48,713 --> 00:40:52,015 He played a leading role in every major spacecraft mission 637 00:40:52,049 --> 00:40:54,517 to explore the solar system during the first 40 years 638 00:40:54,585 --> 00:40:56,920 of the Space Age. 639 00:40:58,689 --> 00:41:01,558 But that's not all he did. 640 00:41:03,794 --> 00:41:07,897 This is Carl Sagan's own calendar from 1975. 641 00:41:09,867 --> 00:41:12,869 Who was I back then? 642 00:41:12,903 --> 00:41:15,705 I was just a 17-year-old kid from the Bronx 643 00:41:15,739 --> 00:41:18,107 with dreams of becoming a scientist, 644 00:41:18,142 --> 00:41:21,444 and somehow the world's most famous astronomer found time 645 00:41:21,479 --> 00:41:24,280 to invite me to Ithaca, in upstate New York, 646 00:41:24,315 --> 00:41:26,082 and spend a Saturday with him. 647 00:41:26,116 --> 00:41:29,519 I remember that snowy day like it was yesterday. 648 00:41:29,553 --> 00:41:31,354 He met me at the bus stop 649 00:41:31,388 --> 00:41:34,257 and showed me his laboratory at Cornell University. 650 00:41:34,291 --> 00:41:38,728 Carl reached behind his desk and inscribed this book for me. 651 00:41:42,466 --> 00:41:45,134 "For Neil, a future astronomer. 652 00:41:45,169 --> 00:41:46,970 Carl." 653 00:41:47,004 --> 00:41:50,406 At the end of the day, he drove me back to the bus station. 654 00:41:50,441 --> 00:41:52,408 The snow was falling harder. 655 00:41:52,426 --> 00:41:54,410 He wrote his phone number-- his home phone number-- 656 00:41:54,445 --> 00:41:57,914 on a scrap of paper and he said, "If the bus can't get through, 657 00:41:57,948 --> 00:42:01,751 call me and spend the night at my home with my family." 658 00:42:01,785 --> 00:42:04,587 I already knew I wanted to become a scientist, 659 00:42:04,622 --> 00:42:06,990 but that afternoon, I learned from Carl 660 00:42:07,024 --> 00:42:09,259 the kind of person I wanted to become. 661 00:42:09,293 --> 00:42:12,929 He reached out to me and to countless others, 662 00:42:12,963 --> 00:42:17,433 inspiring so many of us to study, teach and do science. 663 00:42:17,468 --> 00:42:19,836 Science is a cooperative enterprise, 664 00:42:19,870 --> 00:42:22,238 spanning the generations. 665 00:42:22,273 --> 00:42:26,576 It's the passing of a torch from teacher to student to teacher, 666 00:42:26,610 --> 00:42:30,079 a community of minds reaching back to antiquity 667 00:42:30,114 --> 00:42:32,081 and forward to the stars. 668 00:42:32,116 --> 00:42:34,918 Now, come with me. 669 00:42:34,952 --> 00:42:38,354 Our journey is just beginning. 670 00:43:04,248 --> 00:42:38,354 Captioned by Media Access Group at WGBH access.wgbh.org