Cosmos; No. 6; Travelers' Tales

<v Speaker>Major funding for Cosmos was provided by the Atlantic Richfield Company. <v Speaker>Additional funding was provided by the Corporation for Public Broadcasting <v Speaker>and the Arthur Vining Davis Foundations. <v Speaker>[music] <v Host>Imagine that we are travelers from the stars bound

<v Host>for the sun. We would discover it's surrounded by four giant <v Host>cloudy gas worlds Neptune and its frozen Triton. <v Host>[music] And then <v Host>farther in uranus and its dark rings made perhaps <v Host>of organic matter. [music] Saturn, <v Host>the jewel of the solar system set <v Host>within concentric rings composed <v Host>of a billion icey noodles. <v Host>And finally, <v Host>flanked by massive sattelites, the largest planet,

<v Host>jupiter. It's multicolored clouds, studded <v Host>with flashes of lightening. <v Host>Still farther in, closer to the summit, there are no more giant planets <v Host>only a host of lesser worlds made of rock <v Host>and metal, some with a thin envelope of air . <v Host>They huddle about the sun with almost no internal heat of their own. <v Host>Tiny places with <v Host>solid surfaces, one of which is a blue and <v Host>tricky world called earth. <v Host>Half covered with clouds it is the home planet travelers who have just learned <v Host>to sail the sea of space, to investigate close <v Host>up Jupiter, Saturn, Uranus and Neptune- its brothers

<v Host>and sisters in the family of the Sun. <v Host>Human voyages of exploration to the outer solar system are controlled <v Host>so far from a single place on the planet Earth. <v Host>The Jet Propulsion Laboratory of the National Aeronautics and Space Administration <v Host>in Pasadena, California. <v Host>Here on Sunday, July 8, 1979, the Voyager <v Host>2 spacecraft began its close passage to Jupiter and its moons <v Host>[office noises and talking] <v Host>The spacecraft had been instructed how to explore the Jupiter system by a sequence <v Host>of commands radioed earlier to its onboard computers.

<v Host>[office talking and mumbling] Here we check how faithful an emissary Voyager is. <v Host>Does it understand the commands? <v Host>How is its health? Its temperature? <v Host>It's brains? It's heart? <v Host>[office talk, mubmling] <v Host>The modern ships that sailed to the planets are unmanned. <v Host>They are beautifully constructed, semi-intelligent robots. <v Host>Voyager's eyes are 2 television cameras designed to take tens <v Host>of thousands of pictures in the outer solar system. <v Host>Along with other instruments, they are mounted on a scanned platform which points

<v Host>at passing planets. <v Host>Voyager's brains are 3 integrated computers set amidships. <v Host>It communicates with Earth through a large radio antenna mounted like a sail. <v Host>Voyager bears a message for any alien civilization that may one day encounter <v Host>in interstellar space. <v Host>It's louvers open-and-shut to help control the onboard temperature. <v Host>But Voyager cruises so far from the sun that it cannot depend on solar <v Host>power. Instead, it has a small nuclear power plant <v Host>quarantined from the rest of the ship. <v Host>Many things can go wrong in such pioneering missions, so people are <v Host>a little uneasy at Voyager Mission Control. <v Host>Jupiter is surrounded by a shell of invisible but extremely dangerous high

<v Host>energy charged particles. <v Host>If Voyager flies too close, it's a delicate electronics will be fried. <v Host>A collision with a small boulder in the rings of Jupiter could send the spacecraft <v Host>tumbling wildly out of control. <v Host>Its antenna unable to find the Earth. <v Host>Its data lost forever. [explosion sounds] Voyager 1 and Voyager 2 were launched a month apart in the late summer of 1977. <v Host>After too many alarms and close calls, they successfully arrived months apart at the <v Host>Jupiter system where they worked brilliantly, providing the first <v Host>clues of views of mighty Jupiter and its four large and mysterious moons. <v Host>Io, the inner most of the four, Europa and <v Host>moving away from Jupiter, Ganymede. <v Host>And the outermost big moon, Callisto.

<v Host>For a mission that cost a penny a world <v Host>for every human on the planet Earth. <v Host>Voyager's passage by Jupiter accelerated towards a close encounter <v Host>with the planet Saturn. Saturn's gravity will propel it on to Uranus. <v Host>And in this game of cosmic billiards after Uranus, it will plunge <v Host>on past Neptune, leaving the solar system and becoming an interstellar <v Host>spacecraft destined to wander forever the <v Host>great ocean between the stars, and Voyager should, sometime <v Host>in its distant future, encounter beings from some <v Host>other civilization in space. <v Host>It bears a message. <v Host>A phonograph record, golden, delicate with <v Host>instructions for use on this record are a sampling of pictures,

<v Host>sounds, greetings and an hour and a half of exquisite music. <v Host>The Earth's greatest hits. <v Host>A gift to cross the cosmic ocean from one island civilization <v Host>to another. <v Host>The record bears in English an additional little <v Host>hand-written reading. It says to the makers of music, all <v Host>worlds all times. These voyages of exploration <v Host>and discovery are the latest in a long series which have characterized <v Host>and distinguished the human species. <v Host>In the 15th and 16th centuries, you could travel from Spain to the Azores <v Host>in a few days, the same time it takes now to cross that little channel from <v Host>the earth to the moon. <v Host>It took them a few months to traverse the Atlantic Ocean and reach what was called <v Host>the New World, the Americas. <v Host>Today, it takes a few months to cross the ocean of the inner solar system and reach Mars

<v Host>and Venus, which are truly and literally new worlds awaiting us. <v Host>In the 17th and 18th centuries, you could travel from Holland to China, say, <v Host>a year or two, the same time it takes now for Voyager to travel from the Earth <v Host>to Jupiter. <v Host>And in comparison to the resources of the society, it cost more then <v Host>to send sailing ships to the Far East than it does now to send spaceships to the <v Host>planets. [music]The <v Host>passion to explore is at the heart of being human. <v Host>This impulse to go, to see, to know has found expression in every <v Host>culture. <v Host>Africa was circumnavigated by Phoenician sailors in the employ <v Host>of an Egyptian pharaoh in the seventh century B.C.. <v Host>The islands of the Pacific were settled by skilled and heroic navigators from Indonesia.

<v Host>Great fleets of ocean-going junks left the ports of Ming Dynasty, <v Host>China, to explore India and Africa. <v Host>A century later, three ships left Spain under the command of an Italian navigator <v Host>to discover the Americas. <v Host>And then a Portuguese expedition succeeded in sailing all the way around <v Host>this blue globe. <v Host>These voyagers of many cultures were the first planetary explorers. <v Host>They have bound the earth up into one world. <v Host>In our exploration of other worlds, we follow in their footsteps. <v Host>Our present spaceships are the harbingers, the vanguard <v Host>of future human expeditions to the planets. <v Host>We have traveled this way before. <v Host>There is much to be learned by studying those great voyages

<v Host>of a few centuries ago. [music] In <v Host>the 17th century, the citizens of the new Dutch Republic pursued <v Host>a course of vigorous planetary exploration. <v Host>Holland was then a revolutionary society. <v Host>It had just declared its independence from the powerfu but stagnant Spanish empire. <v Host>And with a newfound self-confidence, Holland embraced more fully than any <v Host>other nation of its time the spirit of the European Enlightenment. <v Host>It was a rational, orderly and creative society, but because Spanish <v Host>ports and vessels were closed to the Dutch, the economic survival of the tiny republic <v Host>depended on its ability to construct man and operate the great fleet

<v Host>of commercial sailing vessels. <v Host>The Dutch East India Company was a combined governmental and commercial enterprise <v Host>which sent shipping to the far corners of the world to acquire rare commodities <v Host>and resell them at a profit in Europe. <v Host>Such voyages were the lifeblood of the republic. <v Host>[music] Navigational <v Host>charts and maps were classified as state secrets. <v Host>Ships sometimes left with sealed sailing orders. <v Host>The crew's embarking for an unknown destination. <v Host>More than a year away on the far side of the planet. <v Host>These expeditions were not only commercial exploitation, although there was certainly <v Host>plenty of that. Aside the usual appeals of ambition, greed, <v Host>national pride and the thirst for adventure, The Dutch were also motivated <v Host>by a powerful scientific curiosity and a fascination with all things

<v Host>new- new lands, new peoples, new plants and animals. <v Host>This building, then the Amsterdam Town Hall, still attests <v Host>to the hardy self-assurance of its 17th century architects. <v Host>Its lavish crystal adornments still reflect the glittering <v Host>pride they felt in their accomplishments and their prosperity. <v Host>It took shiploads of marble to build this place. <v Host>Constantine Huygens, a poet and diplomat of the time, said <v Host>that this town hall dispelled what he called the Gothic squint <v Host>and squalor. [music] The Middle Ages had ended. <v Host>The Englightenment had begun. <v Host>Up there, do you see? Is Atlas supporting the heavens <v Host>on his shoulders.

<v Host>And beneath is justice with <v Host>a golden sword and golden scales flanked <v Host>by death and punishment. <v Host>And who is it that justice is trampling underfoot? <v Host>Why, it's avarice and envy, <v Host>the gods of the merchants. <v Host>The Dutch knew that the unrestrained pursuit of profit posed serious <v Host>threats to the soul of the nation. <v Host>A less allegorical symbol is down here on the floor. <v Host>It is a great inlaid map stretching <v Host>from West Africa to the Pacific Ocean. <v Host>The whole world was then Holland's arena. <v Host>In a typical year, many sailing vessels set out halfway around <v Host>the world for the Far East on voyages of exploration and discovery

<v Host>of trade journeys taking years to accomplish. <v Host>Down the west coast of Africa, through what they call the Ethiopian sea. <v Host>Skirting the southern coast of Africa through the Straits of <v Host>Madagascar and on past the southern tip of India <v Host>to the Spice Islands present day Indonesia. <v Host>Another set of voyages went south and east to New Holland, later renamed <v Host>Australia. <v Host>And still other journeys ventured through the straits of Malacca to <v Host>the empire of China. <v Host>But Holland was a small country forced to live by its wits. <v Host>There was a strong pacifist element in its foreign policy. <v Host>Never before or since has Holland boasted such a galaxy of scientists,

<v Host>mathematicians, philosophers and artists. <v Host>This was the time of the great painters, Rembrandt <v Host>and Vermere.Because Holland <v Host>was tolerant of unorthodox opinions. <v Host>It was a refuge for intellectuals fleeing the thought control <v Host>and censorship of other parts of Europe. <v Host>Much as the United States benefited enormously in the 1930s from the <v Host>exodus of intellectuals from Nazi dominated Europe. <v Host>And so it was that 17th century Holland was the home of the great Jewish <v Host>philosopher Spinoza who Einstein admired so much, <v Host>of Rene Descartes, a pivotal figure in the history of philosophy <v Host>and of mathematics, and the home of a political scientist named <v Host>John Locke, who was to have a powerful <v Host>and profound influence on a group of philosophically inclined

<v Host>revolutionaries named Paine, Hamilton, <v Host>Adams, Franklin and Jefferson. <v Host>The Dutch University of Leiden offered a professorship to <v Host>an Italian scientist named Galileo who had been forced <v Host>by the Catholic Church under threat of torture, to recant <v Host>the heretical position that the earth went around the sun <v Host>and not visa versa. <v Host>Galileo had close ties with Holland. <v Host>His first astronomical telescope was based on a spyglass of Dutch manufacturer. <v Host>And with it, he discovered the crators of the moon, the phases <v Host>of Venus and the four large moons of Jupiter. <v Host>Becoming an exploratory power made Holland the vital intellectual and cultural <v Host>center as well. The improvement of sailing ship technology spurred technology <v Host>in general.

<v Host>A key problem in navigation was the determination of longitude. <v Host>Latitude could be determined easily. <v Host>The farther south you were, the more southern constellations you could see. <v Host>But longitude required precise time keeping. <v Host>An accurate shipboard <v Host>clock would continue to keep the time in your home port. <v Host>The rising and setting of the stars would give you the local time and <v Host>the difference between the two would tell you how far east or west you had gone. <v Host>Technological advance required the freest possible pursuit of knowledge. <v Host>So Holland became the leading publisher and bookseller in Europe, translating <v Host>works written in other languages and printing books that had been censored elsewhere. <v Host>Adventures into exotic lands and encounters with strange societies <v Host>shook complacency. <v Host>They challengeed the prevailing wisdom, and showed that ideas which had been accepted <v Host>for thousands of years would be fundamentally an error.

<v Host>[music] <v Host>In a time when kings and emperors ruled much of the planet, the Dutch <v Host>Republic was governed more than any other world power by the people. <v Host>They enjoyed a certain material well-being, but the interiors <v Host>of their houses, celebrated by a generation of Dutch painters, suggest <v Host>restraint and discretion. <v Host>The officers of these ships of exploration and trade would return from <v Host>their long voyages, share in the goods they had acquired and <v Host>discuss the wonders they had encountered.

<v Host>[music] Holland prospered in its freedom of thought. <v Host>In Italy, Galileo had announced other worlds. <v Host>Giordano Bruno had speculated on intelligent life elsewhere. <v Host>For this, they were made to suffer brutally. <v Host>But in Holland, the astronomer Christian Huygens, who strongly supported both <v Host>ideas, was showered with honors. <v Host>Christian was the son of Constantine Huygens. <v Host>The older Huygens distinguished himself as a master diplomat of the age, <v Host>a man of letters, a close friend and translator of the English poet John Donne.

<v Host>Constantine Huygens was also an accomplished composer and musician. <v Host>It was Constantine who had discovered a young painter named Rembrandt van Rijn <v Host>and several of whose works he subsequently appears. <v Host>He opened the doors of his house to artists, musicians, writers, statesmen <v Host>and scientists. <v Host>A feast of goods and ideas from all over the world awaited. <v Host>The philosopher Descartes who visited him here said of Constantine Huygens, <v Host>'I could not believe that a single mind could occupy itself with so <v Host>many things and acquit itself so well in all of them.' <v Host>He even excelled at the art of parenthood.

<v Host>He was a tender and loving father. <v Host>His son, Christian, flourished in this rich environment, demonstrating extraordinary <v Host>talent for languages, drawing, law, science, engineering, mathematics <v Host>and music. <v Host>'The world is my country,' he said, 'Science, <v Host>my religion.' <v Host>Light was the motif of the age. <v Host>The symbolic enlightenment to freedom of thought and religion. <v Host>The light that suffused the paintings of the time and light as <v Host>an object of scientific study. <v Host>The microscope was invented in Holland at this time and became a drawing <v Host>room curiosity. <v Host>Its inventor was a friend of Christian Huygens, a man named Antonie van Leeuwenhoek. <v Host>The first microscopes were developed from magnifying glasses used by drapers

<v Host>to examine the quality of cloth. [music] Leeuwenhoek and Huygens <v Host>are the grandfathers of much of modern medicine because <v Host>to his amazement Leeuwenhoek discovered a universe <v Host>in a drop of water. The microbes which he described as animal <v Host>fuels and thought cute. <v Host>Leewenhoek <v Host>and Huygens were among the first people to see human sperm cells, the <v Host>hitherto hidden microcosm of the human life cycle. <v Host>Leewenhoek who had discovered the microbial world. <v Host>Huygens had argued from his telescopic observations that Mars <v Host>was another world and probably inhabited.

<v Host>What a waste of a planet he thought if Mars were barren. <v Host>So the Viking search for microbes on Mars can be traced directly <v Host>back to Huygens and Leewenhoek in 17th century Holland. <v Host>The <v Host>telescope and the microscope developed here represent an extension <v Host>of human vision to the realms of the very small and the very <v Host>large. [music] Our <v Host>observations of atoms and galaxies were launched <v Host>this time and place. From <v Host>the bending of light through a lens, Huygens advanced the idea that <v Host>light was a kind of wave.

<v Host>He ground and polished lenses for the successively larger telescopes he constructed. <v Host>Although it did take him a time to figure out how to use <v Host>them properly. <v Host>Huygens was the first person to see a surface feature on the planet Mars. <v Host>He was the first person to speculate that Venus is completely covered with clouds. <v Host>He was the first person to understand the nature of the rings of Saturn. <v Host>Saturn is surrounded, he wrote, by a thin, flat ring which <v Host>nowhere touches the body of the planet. <v Host>His discoveries with the telescope would by themselves have ensured his place <v Host>in the history of human accomplishment.

<v Host>Huygens was the discoverer of Titan, the largest moon of Saturn, <v Host>and as we now know, the largest moon in the solar system. <v Host>The immense size and changing clouds of Jupiter entranced him. <v Host>Astronomers as well as navigators need accurate clocks to time <v Host>the movement of the heavens. <v Host>Huygens was the inventor of many precision timepieces, including the pendulum <v Host>clock. <v Host>To illustrate the sun centered universe of Copernicus, he built <v Host>computers that reproduced the clockwork of the heavens from Mercury <v Host>to Center.

<v Host>The machines he designed he signed, Christian Huygens, <v Host>inventor. <v Host>He was delighted that the Copernican system was widely accepted in everyday life in <v Host>Holland and acknowledged by all astronomers except those he wrote who <v Host>were a bit slow witted or under the superstitions imposed by merely <v Host>human authority. <v Host>Across the sea of space, the <v Host>stars are other suns, <v Host>a point which Huygens appreciated perfectly well. <v Host>He reasoned that if our planetary system <v Host>involved the sun and planets going around it, that those other suns <v Host>should likewise have a retinue of planets going around them and also <v Host>that many of the other planets were inhabited.

<v Host>He set forth these conclusions in a remarkable book <v Host>bearing the triumphant title, The Celestial Worlds <v Host>Discovered. The subtitle is Conjectures Concerning <v Host>the Inhabitants, Planets and Productions <v Host>of the Worlds in the Planets. <v Host>He wrote this book sometime shortly before his death in the year 1690 <v Host>in this study. By <v Host>and large, Huygens imagined that the environments of the other planets <v Host>and also the inhabitants of the other planets were pretty much like <v Host>those of 17th century Europe. <v Host>I wonder if he imagined travel to those other worlds, which she had been <v Host>the first to examine close up through the telescope.

<v Host>Perhaps he dreamt that the voyages of discovery to the planets would one day <v Host>be rather like the voyages of geographical discovery in his time and place. <v Host>He did imagine of extraterrestrial beings. <v Host>'That their whole bodies and every part of them may be quite distinct <v Host>and different from ours tis a very ridiculous opinion,' he says, <v Host>'that it is impossible a rational soul should dwell in any other shape <v Host>than ours.' You could be smart Huygens was saying <v Host>even if you looked funny. But he then went on to argue that they didn't <v Host>look all that funny, that extra terrestrial beings must have <v Host>hands and feet to stand upright and have writing and geometry. <v Host>And even that the four big moons of Jupiter, the Galilean satellites, were there <v Host>in order to provide a navigational aid or convenience

<v Host>for the sailors in the Jovian oceans. <v Host>Well, maybe.[music] <v Host>That bit of speculation is probably wrong, but think <v Host>of a citizen of the 17th century with the courage and insight <v Host>to imagine other landscapes and other intelligences. <v Host>Might there really be mariner's on a million other worlds? <v Host>In his book, Huygenss wrote, 'What a wonderful and amazing scheme <v Host>have we here of the magnificent vastness of the universe, <v Host>so many suns, so many earths, and every one of <v Host>them stucked with so many animals adorned with <v Host>so many seas. <v Host>How must our wonder and admiration be increased when we consider the prodigious <v Host>distance and multitude of the stars.'

<v Host>The Dutch called their ships flying boats and the Voyager <v Host>spacecraft are their descendants. <v Host>True flying boats bound for the stars and on <v Host>the way exploring some of those worlds, which Christian Huygens, <v Host>a man from Earth, knew and loved so well. <v Host>Traveler's Tales, one of the main commodities returned by <v Host>those sailing ship voyages of centuries ago were stories, <v Host>stories of alien lands and exotic animals. They <v Host>evoked the sense of wonder and stimulated further exploration. <v Host>Those tales of strange worlds enabled some Europeans to see themselves <v Host>anew. There had been accounts of headless people, foot people,

<v Host>cyclops people. Now the Dutch brought back fantastic <v Host>stories of giant hunters, dodos, <v Host>rhinos, leopards and other <v Host>creatures. <v Host>Modern voyagers also return travelers tales, <v Host>tales of a world shattered like a crystal sphere. <v Host>A place where the ground is covered <v Host>with what looks like a network of giant cobwebs. <v Host>Tiny moons shaped like potatoes. <v Host>The yellow and red pockmark glen with leaks of molten sulfur <v Host>and volcanic eruptions 300 kilometers high.

<v Host>And a place called Jupiter so large that a thousand earths could fit inside. <v Host>There are no mountains, valleys, volcanoes or rivers there, just a vast <v Host>ocean of gas and clouds. <v Host>Everything we see on Jupiter is floating in the sky. <v Host>But there is much that is fascinating about Jupiter. <v Host>As the solar system condensed out of interstellar gas and dust, Jupiter acquired <v Host>most of the matter that wasn't ejected into interstellar space and which didn't fall <v Host>inwards to form the sun. <v Host>Jupiter is made mostly of hydrogen and helium, just like the sun. <v Host>And had Jupiter been a few dozen times more massive, <v Host>the matter in it might have undergone thermonuclear reactions <v Host>in the interior, and Jupiter would have begun to shine by its own <v Host>light. Jupiter is a star that failed.

<v Host>Had it become a star, we would be living in a double star system with <v Host>two suns in our sky, and the nights would come more rarely. <v Host>Deep below the clouds of Jupiter, the weights of the overlying layers of atmosphere <v Host>produced pressures which are much greater than any that are found anywhere on the earth. <v Host>The clouds are just this little layer here. <v Host>The deep interior is this high pressure place. <v Host>The pressure is so large that electrons are squeezed off, hydrogen atoms <v Host>producing liquid metallic <v Host>hydrogen. But at the very core of Jupiter, <v Host>there may be a lump of rock and iron. <v Host>A giant Earthlike world under astonishing pressures <v Host>is hidden forever at the center of the largest planet. <v Host>Just before Voyager encountered Jupiter, you could see

<v Host>that giant planet at night shining in the sky, as <v Host>our ancestors have for the last million years. <v Host>And on my way to study the Voyager data arriving here at the Jet Propulsion <v Host>Laboratory, I thought that Jupiter would never be the same again. <v Host>Never again just a point of light in the night sky, but forever <v Host>after a place to be explored and known. <v Host>To see the first close up images of a world never before known, <v Host>this moment is one of the greatest joys in the life of the planetary scientist. <v Host>[mumbling voices] In the early morning hours of July <v Host>9, 1979, on the real-time television monitors at the Jet Propulsion <v Host>Laboratory, we began to learn about a world called Europa. <v Host>These are the modern explorers, men and women trained in astronomy, <v Host>physics, geology or engineering. <v Host>Many of them have devoted five to eight years to this single mission.

<v Speaker>Casson's model for Europa says that if you started off with a liquid, you <v Speaker>could probably pump in enough energy to keep it liquid. <v Speaker>[talking over each other] <v Speaker>But the Casson thing said that in order for there to be enough heating going on, you sort <v Speaker>of had to start the heating before Europa basically cooled off. <v Speaker>[sounds of agreement and talking over each other] <v Speaker>What about the relief from the cracks? <v Speaker>Shouldn't the cracks in Io ebb and flow also [talking over each other] <v Speaker>Io and Europa, there's a twin, pair there, and then there's a pair of <v Speaker>?Ganymede's?blister. <v Host>You can't look at the surface of a world so different from ours without wondering <v Host>how both were made. <v Speaker>Just rotate it out a little bit. <v Host>Voyager presented us with six new worlds and the Jupiter system alone. <v Host>The more you learn about other worlds, the better you understand our own. <v Host>We speculate, criticize, argue, calculate, reflect and wonder. <v Host>We return again and again to the astonishing data, and slowly <v Host>we begin to understand. <v Host>[music] Dutch sailing ships brought back rare and valuable commodities from the new

<v Host>worlds they visited. Our voyage of spaceships return rare and valuable information <v Host>to computerized wharves on this shore of the sea of space. <v Host>Here the data are unloaded to be stored, enhanced, processed and <v Host>treasured. Maps of alien lands will be generated from this information. <v Host>In this electronic warehouse are tens of thousands of images of previously <v Host>unknown worlds. <v Host>How does a picture from the outer solar system get to us? <v Host>Sunlight shines on Europa is reflected back to space where some of it strikes the <v Host>phosphers of the Voyager television cameras, generating an image. <v Host>The image is radioed back across the immense intervening distance of half <v Host>a billion kilometers to a radio telescope on earth, one in Australia say. <v Host>The telescope then passes the information via communications <v Host>satellite in earth orbit to Southern California.

<v Host>There it's transmitted by a set of microwave relay towers to a <v Host>computer at the Jet Propulsion Laboratory. <v Host>And there it is processed. <v Host>The picture is fundamentally like a newspaper wire made of perhaps a million <v Host>individual dots of differing shades of gray. <v Host>So fine and close together that at a distance the constituent thoughts <v Host>are invisible. We see only their cumulative effect. <v Host>The information from the spacecraft specifies how bright or dark each dot is to be. <v Host>After processing, the dots are then stored on a magnetic disk, something like a <v Host>phonograph record. <v Host>By this day, there are already 11,000 pictures from Voyager 2 in our electronic library. <v Host>Finally, the end product of this remarkable set of <v Host>links and relays is a hard copy which comes out of

<v Host>this machine showing in this case, the wonders <v Host>of Europa, which were recorded for the first time in human history today. <v Host>It is absolutely astonishing. <v Host>See, Voyager 1 got very good pictures of the other three big moons, <v Host>Galilean satellites of Jupiter, but not of Europa. <v Host>It was left to Voyager 2 today to get the first close <v Host>up pictures of Europa, where we see things that are only a few kilometers across. <v Host>And at first glance, it looks like nothing so much as the canal <v Host>network of Mars that Percival Lowell imagined to exist on that planet. <v Host>We see an amazing, intricate network of criss crossing <v Host>straight and curved lines. <v Host>Are these great lines ridges? <v Host>Are they troughs? Is it connected with plate tectonics on the earth? <v Host>How does it illuminate the other satellites of the Jovian system?

<v Host>At this moment, the vaunted technology has produced something <v Host>astonishing. But it remains for the limitations <v Host>and cleverness of another device, the human brain, <v Host>to figure it out. <v Host>[music] Fortunately, we have plenty of pictures to help us. <v Speaker>What about Gene's idea of geyser's down the troughs? <v Larry Soderblom>Geysers down the troughts? <v Larry Soderblom>Well, you got to have a mechanism to drive it. <v Host>Larry Soderblom, Voyageur Imaging team. <v Larry Soderblom>We had a wild idea a few months ago, we might have some sort of <v Larry Soderblom>champagne bottle models. What that is is you seal the crust and you have liquid <v Larry Soderblom>underneath that solid crust. <v Lonnie Lee>The question is, do you have them- That kind condition, which is an explosive. <v Speaker>Lonnie Lee, Deputy Project scientist <v Lonnie Lee>Over a large area. I thought you'd have enough resolution and with some of these pictures <v Lonnie Lee>that you don't see something that spread laterally.

<v Larry Soderblom>Do we have the high resolution piece to look? <v Speaker> It was here somwhere. Here it is. <v Larry Soderblom>This is where we pick up the relief. If we're going to see things we can recognize <v Larry Soderblom>just. <v Host>Weeks after the pictures from Europa were received we were still debating what was <v Host>in there. <v Speaker>It's as if we almost got to the- here's another thing. <v Speaker>Look at the little mesas here. <v Speaker>Very bright. <v Speaker>You almost got to the limit of resolution required to see the craters, the craters, which <v Speaker>would last indefinitely on a crust this thin. <v Host>Apart from the Russos, there is a set of finse, small, dots <v Host>markings, which are mostly in the model terrain. <v Host>Yeah. Like- like those guys. Now, do you think those are sites of <v Host>outgassing? Calderas, fumaroles sulphateries? <v Larry Soderblom>But I tell you, one thing I just picked up was look at this. <v Larry Soderblom>Yeah, right here. <v Larry Soderblom>Oh, it disappeared. <v Speaker>Oh, yeah. <v Speaker>That's a central peak. <v Host>Yeah, yeah. This little hole.

<v Host>Yeah,. <v Larry Soderblom>It's a- I don't see a radial pair there. <v Larry Soderblom>I think it's got to be- in fact it looks like a central peak there. <v Host>There's always no end peckers on this one. <v Larry Soderblom>Well, well we just found one. <v Host>Almost not [laughter], therefore finding one which is alleged <v Host>to be the exception. <v Larry Soderblom>No I'm not-. <v Host>Maybe it's not the exception but something else. <v Larry Soderblom>Perhaps but I know you asked about all those little holes that we can't quite make out. <v Host>So you could argue that that resolution libidinal, the big the big crater is go away by <v Host>some real logical deformation. And the little ones stay, but they're just at the <v Host>edge of our. <v Larry Soderblom>That's because there are one tenth the depths of the solid, rigid cross. <v Host>Well, maybe. <v Host>Computer processing of the pictures has revealed at least a few features on Europa, which <v Host>seem to be impact craters, but something has wiped out the big craters. <v Host>Computer processing also played a major role in one of the most amazing Voyager <v Host>discoveries made on the moon next door to Europa, a world called Io. <v Host>Even from Earth, we could tell that Io had a strange color.

<v Host>We knew that somehow sulphur had been removed from its surface and injected into <v Host>a great donut of gas orbiting Jupiter. <v Host>Then Voyager 1 sailed close to Io. <v Host>[music] There were a few places <v Host>on Io which looked like the mouths of volcanoes, but it was hard to be sure. <v Host>Then Linda Morabito, a member of the Voyager navigation team, used <v Host>a computer to enhance a picture of the edge of Io in order to bring out the stars <v Host>behind. <v Linda Morabito>Four days after the Voyager 1 encounter with Jupiter, <v Linda Morabito>I was looking at an optical navigation frame. <v Linda Morabito>Now enhancing this particular quadrant became very evident to me was <v Linda Morabito>an anomalous presence in the upper left left hand corner, just off the limb <v Linda Morabito>of Io. <v Host>What was it? The plume turned out to be exactly in the position of one of the suspected <v Host>volcanoes. <v Linda Morabito>So basically we realized at that point that what we were observing was a volcanic <v Linda Morabito>plume and in fact, a volcanic eruption.

<v Host>Voyager had discovered the first active volcano beyond the Earth. <v Host>We then found the Io has many volcanoes. <v Host>There are at least 9 intermittently active plumes and hundreds, maybe thousands <v Host>of extinct ones. The plumes can eject sulfur and other atoms off <v Host>Io altogether and account for the sulfur clouds surrounding Jupiter. <v Host>Rivers of molten sulfur flow down the sides of the volcanic mountains <v Host>and are the probable source of Io's distinctive colors. <v Host>The volcanoes may be tapping some vast underground ocean of liquid sulfur <v Host>beneath the surface that is only a few thousand years old. <v Host>[music] So <v Host>far in our voyages to the outer solar system, we humans have stayed home <v Host>and sent our robots and computers to explore in our stead. <v Host>Someday, perhaps we'll go ourselves.

<v Host>But suppose, like those Dutch sea captains of the 17th century, <v Host>the computers aboard Voyager can keep a ship log, that log the <v Host>combination of the events of Voyages 1 and 2, might be something like this. <v Host>[music]Day <v Host>1, after much concern about provisions and instruments, we successfully <v Host>lift off from Cape Canaveral on our long journey to the planets <v Host>and the stars. [music] Day <v Host>13, we have taken the first photograph of the earth and moon as worlds <v Host>together in space, a pretty pair. <v Host>Day 170, a problem in the deployment of the boom that supports <v Host>the science scan platform. <v Host>If the problem is not solved, we will be unable to take most of our pictures.

<v Host>Day 207, boom problem solved, but failure of main radio <v Host>transmitter. If the backup transmitter also fails, no one on earth <v Host>will ever hear from us again. <v Host>Day 215, we cross the orbit of Mars and enter the main asteroid <v Host>belt. <v Host>Day 570, we can now make out finer detail on Jupiter <v Host>than the largest telescopes on Earth have ever obtained. <v Host>Day 640, the cloud patterns are distinctive and <v Host>gorgeous. No painter trapped on earth ever imagined a world so <v Host>strange and lovely. <v Host>The white clouds are ammonia crystals, high and cold. <v Host>We do not know the nature of the red brown clouds. <v Host>Maybe phosphorus or sulfur is a stain or perhaps complex organic

<v Host>molecules of the sort that lived 4 billion years ago back on Earth to the origin <v Host>of life. And what is the great red spot? <v Host>It is an immense, swirling column of gas reaching high above the adjacent <v Host>clouds, so large that it could hold half a dozen earths. <v Host>Its motion hypnotizes us. <v Host>Some think that the red spot is a great spinning storm, a million <v Host>years old. <v Host>Day 650 encounter a day of wonders. <v Host>The ship maneuvers so we can take pictures of the multi ringed basin on Callisto, <v Host>images of the astonishing lined surface of Ganymede, a close passage by Europa, and <v Host>a view of volcanic Io.

<v Host>We successfully negotiate the treacherous radiation belts and accomplish <v Host>the ring plain crossing. <v Host>Looking back, we marvel at the rings and see the sun emerge <v Host>from behind the giant planet. [music] <v Host>We are outward bound on our mission to explore the outer solar system. <v Host>Ten thousand years from now Voyager <v Host>will plunge onward to the stars. <v Host>We have made the ships that sail the sea of space. <v Host>We travel past Jupiter, three quarters of a billion kilometers from <v Host>the Sun, Saturn 1.5 billion, Uranus 3 billion, <v Host>Neptune 4.5 billion kilometers away. <v Host>In our ship of the mind, we re-trace the itinerary of the two Voyager

<v Host>spacecraft on their journeys to Saturn and beyond. <v Host>Sutton was first glimpsed through the telescope by Galileo. <v Host>Its ring's first understood by Huygens, but only now do we begin <v Host>to penetrate its deeper mysteries. <v Host>Saturn is the second largest planet in the solar system. <v Host>Like Jupiter, it is cloud covered, rotates once every 10 hours. <v Host>It has a weaker magnetic field, a weaker radiation belt and a grand, <v Host>magnificent, exquisite system of rings. <v Host>The rings are composed of billions of tiny moons, each circling Saturn <v Host>in its own orbit. The biggest gap in the rings is called the Cassini <v Host>division after the colleague of Huygens who first discovered it. <v Host>There are many other gaps. Each produced by the periodic gravitational tugs

<v Host>of one of the larger outer moons. <v Host>[music] From just beneath the ring plane, we see a sky <v Host>full of moons. [music] Within <v Host>the rings individual moons become visible. <v Host>They are orbiting chunks of snow and ice. <v Host>Each perhaps a meter across.

<v Host>In young parts of the ring system, there has not been enough time of collisions <v Host>to round the edges of these fragments, the snowballs <v Host>of Saturn. Far <v Host>from the rings bathed in this red light,

<v Host>we encounter Saturn's immense cloud covered moon, Titan. <v Host>Discovered by Christian Huygens, it is the largest moon in the solar system. <v Host>It has an atmosphere denser than that of Mars and a thick layer of red clouds, <v Host>which are probably composed of complex organic molecules produced by <v Host>solar, ultraviolet light and other energy sources from the methane rich air. <v Host>No ship from Earth has ever penetrated those clouds and viewed close <v Host>up the surface of this tantalizing world. <v Host>It seems likely that the ground is covered, encrusted with organic molecules

<v Host>raining from the sky. [music] Maybe <v Host>volcanoes and valleys of ice and just <v Host>perhaps hiding in the warm places some very different kind of life. <v Host>Near am ice cliff of Titan, through a rare break in the clouds of organic <v Host>molecules, you can see looming and lovely the green planet Saturn. <v Host>It is a view that will still be appreciated centuries from now by our descendants <v Host>who will know it well, as well as we have come to know Hudson's <v Host>Bay and the Barents Sea. <v Host>Indonesia and Australia, and New York. <v Host>They will look back to the time when Titan was first glimpsed by the Voyager spaceships

<v Host>on their epic journeys past the giant planets out of the solar system <v Host>to the great dark between the stars. [music] <v Speaker>Major funding for Cosmos was provided by the Atlantic Richfield Company.

<v Speaker>Additional funding was provided by the Corporation for Public Broadcasting <v Speaker>and the Arthur Vining Davis Foundation's.