0:00:00.085,0:00:02.646 Equipped with his five senses 0:00:02.722,0:00:05.590 man explores the universe around him 0:00:05.660,0:00:07.992 and calls the adventure Science. 0:01:09.375,0:01:12.402 Things around us[br]aren't always what they seem. 0:01:29.167,0:01:33.400 ln the everyday world,[br]we use a simple scale, ourselves 0:01:33.506,0:01:36.271 to know what's small and what's large. 0:01:47.057,0:01:49.549 But what about the worlds that lie beyond? 0:01:52.063,0:01:55.625 What is truly large and truly small? 0:02:04.045,0:02:07.379 To explore, to observe 0:02:07.783,0:02:11.220 to understand the wider world[br]we call the universe: 0:02:12.322,0:02:15.121 This is one of the great human adventures. 0:02:30.278,0:02:35.081 As we look out at the distant horizon,[br]we may ask ourselves 0:02:35.686,0:02:38.952 what is our true place in the universe? 0:02:42.528,0:02:44.894 We are all travelers 0:02:44.965,0:02:47.991 on an unending voyage of discovery. 0:03:27.986,0:03:32.014 More than 25 centuries ago,[br]among the Greek lslands 0:03:32.091,0:03:36.153 here at the vibrant crossroads of Africa,[br]Asia and Europe 0:03:36.564,0:03:41.060 philosophers devised rational theories[br]about the world around them. 0:03:44.875,0:03:47.845 The wondrous waves and foams[br]of nature, they said 0:03:48.179,0:03:49.771 could be understood. 0:04:20.353,0:04:25.054 One Greek thinker suggested[br]that the Earth moved around the sun. 0:04:28.597,0:04:32.831 Another taught that everything,[br]the work of man and nature 0:04:33.137,0:04:36.665 was made of particles too small to see. 0:04:41.414,0:04:44.384 Others estimated the sizes[br]of the Earth and the moon 0:04:44.451,0:04:47.546 and the distances between them,[br]and reasoned 0:04:47.622,0:04:49.283 both were spheres. 0:04:52.428,0:04:56.593 But it would be centuries before we had[br]the tools to extend our vision 0:04:56.800,0:04:59.827 and confirm the wisdom[br]of these early thinkers. 0:05:01.774,0:05:03.435 ln the meantime 0:05:03.509,0:05:07.641 people around the world[br]gazed on the stars and gave them names. 0:05:08.683,0:05:13.383 Most assumed the Earth was the center[br]of an unchanging universe. 0:05:47.866,0:05:49.698 Two thousand years passed 0:05:49.769,0:05:53.570 before a revolutionary breakthrough[br]was made by a mathematics professor 0:05:53.641,0:05:56.941 in the ancient,[br]maritime republic of Venice. 0:05:58.113,0:06:01.572 ln 1609, Galileo Galilei 0:06:01.817,0:06:05.811 demonstrated an instrument[br]that would soon be called a telescope. 0:06:09.995,0:06:11.860 From the tallest bell towers 0:06:11.930,0:06:14.559 he showed the device[br]could spot approaching ships 0:06:14.634,0:06:17.866 hours before their sails were visible[br]to the naked eye. 0:06:19.707,0:06:22.973 Later, when he aimed his telescope[br]at the night sky 0:06:23.245,0:06:26.682 Galileo discovered that the moon[br]was a world of mountains. 0:06:27.351,0:06:29.319 Jupiter had its own moons 0:06:29.453,0:06:32.651 and the Milky Way[br]was a band of countless stars. 0:06:38.065,0:06:40.932 Our own cosmic voyage begins here 0:06:41.135,0:06:44.867 in the center of Galileo's Venice,[br]St. Mark's Square. 0:06:50.780,0:06:54.478 Since the universe is a big place,[br]we could easily get lost 0:06:55.087,0:06:58.580 so we'll need signposts[br]to give us a sense of scale. 0:07:01.627,0:07:04.654 The acrobats' ring is one meter wide. 0:07:08.002,0:07:11.939 The crowd is ten times wider,[br]ten meters across. 0:07:12.007,0:07:14.238 Larger by one power of ten. 0:07:18.583,0:07:21.815 Now, with every step, every ring 0:07:22.287,0:07:25.257 we travel ten times farther from Venice 0:07:25.492,0:07:28.690 and our view of the universe[br]is ten times wider. 0:07:32.100,0:07:34.934 The 100-meter ring surrounds St. Mark's 0:07:35.338,0:07:39.275 and 1,000 meters, one kilometer,[br]the city's center. 0:07:41.513,0:07:45.974 As our speed increases,[br]four steps, four powers of ten 0:07:46.152,0:07:51.182 reveal all the islands of Venice,[br]the Adriatic Sea and Northern ltaly. 0:07:58.568,0:08:03.302 Six steps take in Europe[br]from Germany across to the Balkans. 0:08:07.546,0:08:10.414 And soon, we can see the entire planet. 0:08:11.050,0:08:12.848 Our home in space. 0:08:24.634,0:08:26.830 Eight steps on our outward journey 0:08:26.938,0:08:31.205 eight powers of ten, and we pass[br]the farthest reaches of human travel: 0:08:32.511,0:08:33.672 The moon. 0:08:59.512,0:09:02.949 lf we visualize the paths[br]that the nine planets take 0:09:03.017,0:09:05.145 in their orbits around the sun 0:09:06.455,0:09:09.289 at 13 steps from St. Mark's Square 0:09:09.826,0:09:13.263 the entire solar system comes into view. 0:09:22.576,0:09:26.536 And with 15 steps, 15 powers of ten 0:09:27.248,0:09:30.878 we can see our sun is just another star. 0:09:31.388,0:09:35.155 From here on,[br]our voyage will be measured in light-years. 0:09:35.760,0:09:38.992 The distance light travels in an entire year. 0:09:41.300,0:09:45.102 Only now do we fly past[br]our nearest neighbor stars 0:09:45.706,0:09:48.300 almost five light-years away. 0:09:49.911,0:09:53.177 The same journey at the speed[br]of today's spacecraft 0:09:53.382,0:09:56.580 would last 100,000 years. 0:10:03.729,0:10:06.221 As we cross the perpetual night 0:10:06.299,0:10:09.701 our voyage takes us up and out[br]of our sun's neighborhood 0:10:09.837,0:10:13.035 near the edge[br]of a great pinwheel of stars. 0:10:35.636,0:10:38.367 The Milky Way is actually a spiral galaxy 0:10:38.807,0:10:43.268 and our own sun is just one[br]of a hundred billion stars in it. 0:10:44.515,0:10:48.247 At this immense scale, 23 powers of ten 0:10:48.587,0:10:51.284 each shining light we see is not a star 0:10:51.858,0:10:55.852 but an entire galaxy[br]composed of countless stars. 0:10:57.631,0:11:01.694 Astronomers have discovered[br]galaxies are flying away from one another. 0:11:02.505,0:11:05.441 The universe is expanding. 0:11:07.310,0:11:09.939 Our own galaxy, and all the others 0:11:10.114,0:11:13.573 form clusters and superclusters[br]of stupendous size 0:11:13.786,0:11:16.551 hundreds of millions[br]of light-years across. 0:11:20.227,0:11:24.221 And here, about 15 billion light-years[br]from Venice 0:11:24.933,0:11:28.233 we approach the outer limits[br]of the visible universe. 0:11:29.106,0:11:33.771 What lies beyond this cosmic horizon,[br]we cannot see 0:11:35.113,0:11:37.048 and do not know. 0:11:52.936,0:11:56.931 While Galileo's telescope[br]allowed us to take an outward voyage 0:11:57.008,0:12:00.239 another innovation,[br]here in the Dutch town of Delft 0:12:00.646,0:12:03.638 would lead us on an inward journey[br]of discovery. 0:12:14.531,0:12:16.328 Over three centuries ago 0:12:16.433,0:12:19.995 Anton van Leeuwenhoek[br]perfected the early microscope 0:12:20.271,0:12:23.571 and used it to study droplets[br]from the waterways of Holland. 0:12:42.333,0:12:44.267 Come on, over here. 0:12:47.806,0:12:50.207 As students today[br]make their own discoveries 0:12:50.277,0:12:52.644 imagine the moment[br]when van Leeuwenhoek 0:12:52.713,0:12:55.147 peered through[br]his more powerful instrument 0:12:55.216,0:12:59.587 and discovered a living kingdom[br]in a drop of water. 0:13:07.799,0:13:10.701 This busy world of single-cell paramecia 0:13:11.037,0:13:13.233 is only one millimeter across. 0:13:13.874,0:13:17.242 Three powers of ten smaller than a meter. 0:13:21.350,0:13:25.845 The microscope allows us to continue[br]our journey to the realm of the very small. 0:13:27.325,0:13:29.486 As we move into the cell nucleus 0:13:30.094,0:13:32.586 each new ring now reveals a world 0:13:32.798,0:13:36.428 ten times smaller in diameter[br]than the last. 0:13:39.707,0:13:42.040 Deep within the nucleus 0:13:42.110,0:13:44.841 we come upon[br]truly remarkable constructions. 0:13:45.715,0:13:49.049 Long, spiraling molecules of DNA. 0:13:52.023,0:13:54.116 DNA holds the chemical codes 0:13:54.192,0:13:57.321 for the reproduction of most organisms[br]on the planet. 0:13:57.830,0:14:01.825 Whether they're paramecia,[br]people or petunias. 0:14:09.279,0:14:11.713 Voyaging on, we see that molecules 0:14:11.781,0:14:14.717 are made of even smaller parts[br]called atoms. 0:14:20.993,0:14:24.191 The tiny world of the common atom[br]is very strange indeed. 0:14:25.299,0:14:28.736 lts six electrons seem to swarm[br]everywhere at once. 0:14:32.574,0:14:34.907 Now our voyage takes us through a void 0:14:34.978,0:14:38.210 that appears as vast as the space[br]between the stars. 0:14:39.684,0:14:42.085 Ahead lies the atomic nucleus. 0:14:42.654,0:14:44.520 So fantastically small 0:14:45.024,0:14:48.153 that if the whole atom[br]were the size of this theater 0:14:48.228,0:14:51.255 its nucleus would be like a speck of dust. 0:14:52.701,0:14:56.331 Yet the nucleus contains[br]almost all of the atom's mass 0:14:56.906,0:14:59.273 packed into particles called protons 0:14:59.609,0:15:00.975 and neutrons. 0:15:02.747,0:15:07.651 And these, in turn, are made of smaller,[br]more mysterious things called quarks. 0:15:11.559,0:15:12.992 Exploring this 0:15:13.194,0:15:15.322 the inner frontier of the universe 0:15:15.397,0:15:18.025 physicists wonder[br]if quarks might contain 0:15:18.101,0:15:20.569 even tinier building blocks of matter. 0:15:28.113,0:15:33.075 Scientists are investigating this mystery[br]in an underground tunnel near Chicago 0:15:33.720,0:15:37.020 home of the giant[br]Fermilab particle accelerator 0:15:37.625,0:15:43.122 designed to create conditions[br]like those after the birth of our universe. 0:15:46.871,0:15:49.602 Millions of protons and antiprotons 0:15:49.674,0:15:52.404 race through these pipes[br]in opposite directions 0:15:52.477,0:15:57.041 nearly at the speed of light.[br]A kind of subatomic demolition derby. 0:16:26.054,0:16:29.991 Now our cosmic voyage[br]enters another dimension 0:16:31.295,0:16:33.354 the dimension of time 0:16:33.697,0:16:35.962 where knowledge is much less certain. 0:16:36.801,0:16:39.896 Studying traces of quarks[br]from these collisions 0:16:40.239,0:16:44.074 physicists try to learn[br]what our universe was like when it began 0:16:44.144,0:16:47.273 after the explosion[br]known as the Big Bang. 0:16:50.285,0:16:52.345 One of them outlines the theory. 0:16:53.256,0:16:54.814 Welcome to Fermilab. 0:16:55.158,0:16:57.889 Today, astronomers[br]see the universe expanding. 0:16:58.028,0:17:00.463 lmagine running the expansion backwards. 0:17:00.632,0:17:02.099 Billions of years ago 0:17:02.167,0:17:05.467 everything must've been packed together[br]at enormous density. 0:17:05.570,0:17:06.800 lt seems incredible 0:17:06.906,0:17:08.534 but we think that the matter 0:17:08.642,0:17:12.079 making up everything we see[br]in the universe 0:17:12.480,0:17:16.474 the buildings, trees, people, planets 0:17:16.720,0:17:19.314 stars out to the most distant galaxies 0:17:19.924,0:17:23.917 was once crammed together[br]into a volume smaller than this. 0:17:24.829,0:17:26.058 And then. 0:17:42.185,0:17:45.986 Space itself exploded,[br]in a burst of radiant energy. 0:17:48.260,0:17:50.524 ln those first dazzling moments 0:17:50.796,0:17:54.734 the newborn universe[br]began to expand and cool. 0:17:56.137,0:17:58.834 Quarks combined[br]into protons and neutrons 0:17:59.474,0:18:02.774 which later attracted electrons[br]to form atoms 0:18:03.746,0:18:06.477 and the vast fog lifted. 0:18:21.035,0:18:22.970 For hundreds of millions of years 0:18:23.038,0:18:27.066 the force of gravities slowly drew matter[br]together into a gigantic web. 0:18:27.944,0:18:30.311 The architecture of the cosmos. 0:18:36.789,0:18:38.757 Two billion years passed 0:18:39.727,0:18:43.596 clouds of gas and dust condensed[br]like giant water drops 0:18:43.665,0:18:46.658 along the cosmic strands[br]and formed galaxies. 0:18:59.952,0:19:02.251 Where the great ridges of matter crossed 0:19:02.322,0:19:04.723 galaxies came together in clusters. 0:19:30.124,0:19:33.026 Some galaxies evolved into gigantic discs 0:19:33.395,0:19:36.092 and spirals of stars, gas, and dust. 0:19:37.934,0:19:40.870 Neighboring galaxies trapped[br]by their mutual gravity 0:19:41.372,0:19:44.171 draw together in the fantastic collision. 0:19:45.478,0:19:48.311 ln real time, it would last a billion years. 0:20:27.365,0:20:30.995 The force of gravities[br]stretch long tails of gas and stars 0:20:31.103,0:20:32.934 from the huge new galaxy. 0:20:36.076,0:20:38.136 And yet stars almost never collide 0:20:39.247,0:20:41.614 so vast are the distances between them. 0:20:52.063,0:20:54.258 Perhaps ten billion years pass 0:20:54.967,0:20:57.128 and we encounter our own galaxy: 0:20:57.303,0:20:58.703 The Milky Way. 0:20:59.706,0:21:01.834 ln it, stars have formed 0:21:02.944,0:21:04.673 and some have died. 0:21:09.719,0:21:12.280 Stars are nuclear furnaces. 0:21:12.490,0:21:14.981 They shine until they use up their fuel. 0:21:15.359,0:21:17.988 Massive stars end explosively. 0:21:32.682,0:21:35.709 These exploding stars, or supernovas 0:21:36.521,0:21:38.580 send out the elements of life: 0:21:38.957,0:21:42.359 The oxygen we breathe,[br]the carbon in our muscles 0:21:42.461,0:21:44.191 the iron in our blood. 0:21:45.599,0:21:47.568 Now a cloud of cosmic gas 0:21:47.802,0:21:51.398 sprinkled with these elements,[br]comes together in the grip of gravity. 0:21:57.348,0:22:00.613 A new star, our sun, ignites. 0:22:03.722,0:22:05.714 Around it, planets form. 0:22:08.595,0:22:12.259 ln their infancy,[br]over four billion years ago 0:22:12.767,0:22:15.669 our Earth and moon[br]were bombarded constantly 0:22:15.738,0:22:18.105 by cosmic dust, asteroids 0:22:19.476,0:22:20.704 and comets. 0:23:16.315,0:23:19.615 With violent impacts and volcanic gases 0:23:19.820,0:23:23.882 acid rain, and potent ultraviolet radiation[br]from the sun 0:23:24.660,0:23:27.220 the young Earth was a very hostile world. 0:23:30.800,0:23:34.670 And yet the basic ingredients[br]of life are already here. 0:23:41.949,0:23:42.938 Water 0:23:43.784,0:23:44.945 carbon 0:23:45.754,0:23:47.312 and energy. 0:23:50.626,0:23:54.996 Molecules, sheltered by the sea,[br]somehow combined 0:23:55.098,0:23:58.000 multiplied, and gave rise to life. 0:23:58.436,0:24:03.102 For millions of years,[br]Earth's only organisms were tiny bacteria. 0:24:03.743,0:24:07.009 Some, called blue-green bacteria 0:24:07.181,0:24:10.481 slowly released tiny bubbles of oxygen 0:24:11.019,0:24:14.581 and profoundly changed the atmosphere. 0:24:16.693,0:24:21.859 Above the clouds, some of this oxygen[br]formed a thin layer of ozone 0:24:22.133,0:24:25.626 blocking most of the sun's[br]ultraviolet rays. 0:24:30.978,0:24:33.378 ln this changed environment 0:24:33.649,0:24:36.550 new organisms flourished[br]in the Earth's waters. 0:24:38.121,0:24:41.649 Colonies of green algae[br]produced more oxygen. 0:24:50.002,0:24:53.962 Then, organisms evolved[br]in an astonishing variety of forms. 0:24:55.810,0:24:59.975 Some with shells or skeletons[br]for protection and support. 0:25:10.028,0:25:14.989 Others evolved complex life cycles,[br]like this tiny crustacean. 0:25:16.437,0:25:21.535 The shallow waters of the seas[br]filled with a teaming diversity of life forms. 0:25:34.727,0:25:39.428 Life's next challenge[br]was to colonize the harsh, dry land. 0:25:42.938,0:25:47.899 Bacteria were first, followed by algae,[br]plants, and animals. 0:26:13.376,0:26:17.872 Vertebrates appeared on land,[br]feeding on both plants and animals 0:26:19.585,0:26:23.249 and gave rise to larger[br]and larger life forms. 0:26:26.860,0:26:29.421 Some of them conquered[br]the realm of the air 0:26:30.632,0:26:33.727 and others, the great open plains. 0:26:54.196,0:26:58.099 Our cosmic voyage, from the Big Bang[br]to the appearance of humans 0:26:58.167,0:27:01.194 took about 15 billion years. 0:27:03.008,0:27:05.772 From the beginning, we were explorers 0:27:06.345,0:27:09.212 inventors and technicians. 0:27:17.860,0:27:22.230 And in a few thousand years,[br]just an instant in cosmic time 0:27:22.699,0:27:27.570 curiosity and technology[br]would take us back toward the stars. 0:27:57.744,0:27:59.906 Since it was launched into orbit 0:28:00.081,0:28:02.778 the Hubble space telescope[br]has captured images 0:28:02.851,0:28:05.081 that reveal ever more beautiful 0:28:05.154,0:28:09.421 and mysterious regions of the universe,[br]where stars are dying out. 0:28:13.898,0:28:15.799 And within the Eagle Nebula 0:28:15.968,0:28:20.269 strange towers of glowing gas[br]are giving birth to new stars. 0:28:22.543,0:28:24.534 ln the great Orion Nebula 0:28:24.612,0:28:29.745 discs of dust seem to be turning[br]into solar systems just like our own. 0:28:33.691,0:28:37.958 The grand adventure of cosmic exploration[br]is accelerating rapidly 0:28:38.196,0:28:42.065 taking us into realms[br]that once were the stuff of science fiction 0:28:42.402,0:28:45.338 like the mysterious black hole. 0:28:50.846,0:28:55.045 Here, a red giant star[br]is slowly being consumed 0:28:55.218,0:28:58.916 its gases swirling into the depths[br]of a black hole. 0:29:03.595,0:29:07.931 Some black holes may be collapsed cores[br]of very massive stars 0:29:08.302,0:29:12.467 with gravity so powerful[br]not even light can escape them. 0:29:13.008,0:29:17.469 But they can be detected from their trap[br]and swallow nearby stars. 0:29:27.393,0:29:29.555 For the first time in our history 0:29:29.629,0:29:34.158 we now have strong evidence[br]that there are planets orbiting other stars. 0:29:35.904,0:29:40.365 Scientists think there could be millions[br]of earth-like planets in our galaxy alone. 0:29:44.615,0:29:47.710 lf so, do any of them have life? 0:29:52.592,0:29:54.788 Some radio telescopes search for signals 0:29:54.895,0:29:58.127 that may reveal the presence[br]of alien civilizations. 0:29:59.802,0:30:01.292 lt's a daunting task. 0:30:02.071,0:30:05.166 But, if one day we should receive a signal 0:30:05.709,0:30:08.645 it would forever change our view[br]of ourselves 0:30:09.313,0:30:10.975 and our universe. 0:30:36.315,0:30:40.252 Telescopes, such as the giant[br]Keck Observatory in Hawaii 0:30:40.487,0:30:43.651 are like time machines[br]capturing the faint light 0:30:43.724,0:30:47.161 that has traveled towards us[br]through all of cosmic history. 0:30:48.030,0:30:52.969 The deeper astronomers look into space,[br]the farther back they see in time. 0:31:09.425,0:31:11.757 The more we learn about the universe 0:31:12.294,0:31:14.627 the more new mysteries we uncover 0:31:15.165,0:31:20.264 profound questions for future generations[br]of cosmic explorers. 0:31:23.977,0:31:27.345 Will the universe go on expanding forever? 0:31:28.182,0:31:30.617 Exactly how did life arise? 0:31:31.553,0:31:35.115 Could there be other universes[br]beyond our cosmic horizon? 0:31:35.925,0:31:38.895 And are there others[br]elsewhere in the universe 0:31:39.096,0:31:40.997 asking the same things? 0:31:41.799,0:31:45.236 Even to ask such questions is ambitious. 0:31:45.971,0:31:49.305 But look how far we've traveled[br]since our ancestors 0:31:49.376,0:31:52.869 took the first steps in our cosmic voyage. 0:33:30.038,0:33:34.635 Man must understand his universe[br]in order to understand his destiny. 0:33:35.980,0:33:39.678 Who knows what mysteries[br]will be solved in our lifetime 0:33:40.051,0:33:44.352 and what new riddles will become[br]the challenge of the new generations?