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00:00:00Transcription by CastingWords
00:00:30Martians.
00:00:57Why so many speculations and fantasies about Martians rather than Saturnians, say, or Plutonians?
00:01:06Because Mars seems at first glance very Earth-like.
00:01:10It's the nearest planet whose surface we can see.
00:01:13There are polar ice caps, drifting white clouds, raging dust storms, seasonally changing patterns, even a 24-hour day.
00:01:21It's tempting to think of it as an inhabited world.
00:01:27Mars has become a kind of mythic arena onto which we've projected our earthly hopes and fears.
00:01:35The most tantalizing myths about Mars have proved wrong.
00:01:39So a few people have swung to the opposite extreme and concluded that the planet is of little interest.
00:01:45They've begun to sing blues for the red planet.
00:01:49But the real Mars is a world of wonders.
00:01:53Its future prospects are far more intriguing than our past apprehensions about it.
00:01:59In our time, we have sifted the sands of Mars, established a presence there, and fulfilled a century of dreams.
00:02:13The most startling dream of Mars was that of H.G. Wells, who in 1897 wrote, The War of the Worlds.
00:02:23No one would have believed in the last years of the 19th century that this world was being watched, keenly and closely, by intelligences greater than man's, and yet as mortal as his own.
00:02:37The War of the Worlds
00:02:55The War of the Worlds
00:03:13As men busied themselves about their various concerns, they were scrutinized and studied, perhaps almost as narrowly as a man with a microscope might scrutinize the transient creatures that swarm and multiply in a drop of water.
00:03:29The War of the Worlds
00:03:43With infinite complacency, men went to and fro over this globe about their little affairs, serene in their assurance of their empire over matter.
00:03:53The War of the Worlds
00:03:55It's possible that the Infusoria under the microscope do the same.
00:04:00The War of the Worlds
00:04:04The War of the Worlds
00:04:18No one gave a thought to the older worlds of space as sources of human danger,
00:04:22or thought of them only to dismiss the idea of life upon them as impossible or improbable.
00:04:29The War of the Worlds
00:04:31The War of the Worlds
00:04:32The War of the Worlds
00:04:34It is curious to recall some of the mental habits of those departed days.
00:05:01At most, terrestrial men fancied there might be other men upon Mars, perhaps inferior to
00:05:09themselves and ready to welcome a missionary enterprise.
00:05:16Yet, across the Gulf of Space, intellects vast and cool and unsympathetic regarded this
00:05:24earth with envious eyes and slowly and surely drew their plans against us.
00:05:43Wells' novel captured the popular imagination in the late Victorian era.
00:05:53This was a time when the automobile was a novelty, when the pace of life was still largely determined
00:05:58by the speed of the horse.
00:06:01To this world, Wells introduced an interplanetary fantasy with spaceships, ray guns and implacable
00:06:08aliens.
00:06:09These were original and disquieting possibilities.
00:06:17The Martians of H.G. Wells were not merely minor variations on a human theme.
00:06:23Instead, they were the evolutionary product of a totally alien environment.
00:06:38Forty years later, this fantasy was still able to frighten millions in war jittery America,
00:06:46when it was dramatized for radio by the young Orson Wells.
00:06:57A few years before the War of the Worlds was published, another and quite different vision
00:07:02of Martians was forming in the mind of a wealthy Bostonian named Percival Lowell.
00:07:10The Martians of H.G. Wells were a way for the novelists to examine contemporary society
00:07:14through alien eyes.
00:07:17But the Martians of Percival Lowell were, he believed, very real.
00:07:27It was here that the most elaborate claims in support of life on Mars were developed.
00:07:39Lowell dabbled in astronomy as a young man, he went off to Harvard, he had a semi-official diplomatic
00:07:55appointment to Korea and otherwise engaged in the usual pursuits of the wealthy for his time.
00:08:06But his lifelong love was the planet Mars.
00:08:13Lowell was electrified by the announcement in 1877 by an Italian astronomer, Giovanni Schiaparelli, of Canale on Mars.
00:08:26Schiaparelli had reported during a close approach of Mars to the Earth, an intricate network of single and double straight lines,
00:08:35crisscrossing the bright areas of Mars.
00:08:40Now, Canale in Italian means channels or grooves, but it was promptly translated into English as canals,
00:08:49a word which understandably has a certain implication of intelligent design.
00:08:56A Mars mania swept through Europe and America and Percival Lowell found himself caught up in it.
00:09:06In 1892, his eyesight failing, Schiaparelli announced he was giving up observing Mars.
00:09:13Lowell resolved to continue the work.
00:09:19He wanted a first-rate observing sight, undisturbed by clouds or city lights and marked by good seeing.
00:09:35Seeing is the astronomer's term for a steady atmosphere through which the shimmering of an astronomical image in the telescope is minimized.
00:09:44Lowell built his observatory far away from home on Mars Hill here in Flagstaff, Arizona.
00:10:01Lowell sketched the surface features of Mars, and particularly the canals which mesmerized him.
00:10:26Now, observations of this sort aren't easy.
00:10:31You put in long hours at the telescope in the chill of the early morning.
00:10:35Most of the time the seeing is crummy.
00:10:38When the seeing is bad, the image of Mars blurs and distorts, and you have to ignore what you've observed.
00:10:46But occasionally the image steadies, and the features of the planet marvelously flash out at you.
00:10:53You must then remember what you've seen and accurately committed to paper.
00:10:58You must put your preconceptions aside and with an open mind set down the wonders that Mars holds in store for us.
00:11:06This is Percival Lowell's own notebook.
00:11:10Here's what he thought he saw.
00:11:15Bright and dark areas, a hint of a polar cap, and canals.
00:11:20Lots and lots of canals.
00:11:23Lowell believed that he was seeing a globe girdling a network of great irrigation canals carrying water from the melting polar caps to the thirsty inhabitants of the equatorial cities.
00:11:44He believed the planet was inhabited by an older and wiser race, perhaps very different from us.
00:11:52He believed that the seasonal changes in the dark areas were due to the growth and decay of vegetation.
00:12:01He believed that the planet was Earth-like.
00:12:04All in all, he believed too much.
00:12:09Lowell's Martians were a dying race.
00:12:23Their once great cities had fallen into ruins.
00:12:27Lowell believed that the Martian climate was changing.
00:12:30That the precious water was trickling away into space.
00:12:33That the planet was becoming a desert world.
00:12:36The canals, he thought, were a last desperate measure, a heroic engineering effort to conserve the scarce water.
00:12:45But their technology, although far more advanced than ours, was inadequate to stem a planetary catastrophe.
00:13:15The most serious, contemporary challenge to Lowell's ideas came from an unlikely situation.
00:13:44The biologist, Alfred Russell Wallace, co-discoverer of evolution by natural selection.
00:13:51Wallace correctly showed that the air on Mars was much too cold and thin to permit the existence of liquid water.
00:13:59He wrote that only a race of madmen would build canals under such conditions.
00:14:09Lowell's Martians were benign and hopeful, even a little godlike.
00:14:15Very different from the malevolent menace posed by H.G. Wells and Orson Welles in The War of the Worlds.
00:14:22Both sets of ideas passed into the public imagination through Sunday supplements and science fiction.
00:14:29And excited generations of eight-year-olds into fantasizing that they themselves might one day voyage to the distant planet Mars.
00:14:39I remember reading with breathless fascination the Mars novels of Edgar Rice Burroughs.
00:14:45I journeyed with John Carter, a gentleman adventurer from Virginia, to Barsoom, as Mars was known by its inhabitants.
00:14:54Wandering among the beasts of burden called Thots, winning the hand of the lovely Dejah Thoris, Princess of Helium, and befriending a ten-foot-high green fighting man named Tars Tarkas as the moons of Mars hurtled overhead on a summer's evening on Barson.
00:15:19The End
00:15:28The End
00:15:32The End
00:15:37It aroused generations of eight-year-olds, myself among them, to consider the exploration
00:15:56of the planets as a real possibility, to wonder whether we ourselves might one day venture
00:16:02to the distant planet Mars. John Carter got to Barsoom by standing in an open field, spreading
00:16:10his hands and wishing hard at Mars. I can remember spending many an hour in my boyhood, arms
00:16:18resolutely outstretched in an open field in twilight, imploring what I believed to be Mars
00:16:26to transport me there. It never worked. There had to be some better way. And there was.
00:16:36The real road to Mars was opened by a boy who loved skyrockets.
00:16:41Fourth of July celebrations in New England are much the same today as they were in the 1890s.
00:17:00Then, as now, the highlight of the day's festivities was a rousing fireworks display.
00:17:23That was the part that Robert Goddard liked the best. By the time he was 16, he was launching
00:17:39his own rockets. He wrote in his diary, July 4th, 1898, fired cannon and firecrackers all day.
00:17:50In evening, had five rockets.
00:18:05Wow!
00:18:07That same year, the War of the Worlds was being serialized in the Boston Post. Goddard eagerly
00:18:13read every word. The Boston newspapers were also reporting intriguing conjectures by a Professor
00:18:24Lowell whose lectures Goddard would later attend. The images of Mars spun by Wells and Lowell beguiled
00:18:40the young Goddard. And at age 17, on October 19th, 1899, they crystallized into an overwhelming vision that provided the direction and purpose of his life.
00:18:55From the high branches of an old cherry tree on his family's farm, Goddard saw a way to do more
00:19:10than just speculate about Mars. Before anyone had ever flown in an airplane or listened to a radio, Goddard decided to invent a machine that would voyage to the planet Mars.
00:19:33All right.
00:19:36Let's go.
00:19:38For the rest of his life
00:20:07he was to commemorate that October day as his anniversary day, the birthday of his great dream.
00:20:19By the 1920s, after years of studying physics and engineering, he was experimenting with liquid fuel rockets.
00:20:37In order to build a rocket capable of reaching high altitudes, Goddard had to create the principles of an entirely new technology.
00:20:49He invented the basic components that propel, stabilize and guide the modern rocket.
00:20:57It was painstaking and difficult work, but Goddard took the many setbacks in stride.
00:21:19He sifted the wreckage of each experiment for clues to guide the next.
00:21:31Constantly refining old techniques and inventing new ones, he gradually raised the rocket from a dangerous toy and set it on its way to becoming an interplanetary vehicle.
00:21:43Goddard died in 1945, before a rocket had ever left the planet Earth.
00:22:01Although Mars always remained his objective, Goddard knew that such a goal would be ridiculed.
00:22:07In public, he advocated only the more modest objective of flying to the Moon.
00:22:17Those boyhood dreams of voyages to the Moon and Mars, shared by Goddard with his contemporary, a Russian scientist named Konstantin Tsiolkovsky, were fulfilled only a few decades after their deaths.
00:22:32But, as it turned out, the first planet to be explored by rocket was the Earth.
00:22:49Now, imagine yourself a visitor from some other and quite alien planet.
00:22:54You approach the Earth with no preconceptions.
00:22:56Is the place inhabited?
00:22:58At what point can you decide?
00:23:00When we look at the whole Earth, there are no signs of life.
00:23:03We must examine it more closely.
00:23:06If there are intelligent beings, maybe they create engineering structures which can be seen at a resolution of a few kilometers.
00:23:13Yet, at this level of detail, even a great river valley seems utterly lifeless.
00:23:19There is no sign of life, intelligent or otherwise, in Washington, D.C., or Moscow, or Tokyo, or Peking.
00:23:33If there are intelligent beings on Earth, they have not much modified the landscape into regular geometrical patterns at kilometer resolution.
00:23:40But when we improve the resolution tenfold, when we begin to see detail as small as a hundred meters across, the size of a football field, the situation changes.
00:23:55Many places on Earth seem suddenly to crystallize out, revealing an intricate pattern of straight lines, squares, rectangles, and circles.
00:24:11Canals, roads, circular irrigation patterns all suggest intelligent life with a passion for Euclidean geometry and territoriality.
00:24:22On this scale, intelligent life can be discerned in Boston, and Washington, and New York.
00:24:33At ten-meter resolution, we also discover that the Earthlings like to build up.
00:24:39At twilight or night, other things are visible, oil well fires in the Persian Gulf, or the bright lights of large cities.
00:24:54And at meter resolution, we make out individual organisms, seals on ice floes, or people on skis.
00:25:06Intelligent life on Earth first reveals itself through the geometric regularity of its constructions.
00:25:13If Lowell's Canal Network really existed, the conclusion that intelligent beings inhabit that planet might also be compelling.
00:25:20But there is no Canal Network.
00:25:23Our unmanned spacecraft have examined Mars with a thousand times more detail than any fleeting glimpse available through Percival Lowell's telescope.
00:25:33There is no question that his Martian canals were of intelligent origin.
00:25:38The only question was which side of the telescope the intelligence was on.
00:25:42Where we have strong emotions, we're liable to fool ourselves.
00:25:47Yet, even without the canals, the exploration of Mars evokes the kind of rapture that Columbus or Marco Polo must have felt.
00:25:57We see many impact craters, but we find no canals, none at all.
00:26:07There are fault lines on the surface, and complex patterns of ridges and valleys.
00:26:13But they are all far too small and in the wrong places to be Lowell's canals.
00:26:19And they don't seem to be manufactured.
00:26:22There are many signs of water.
00:26:26Ancient river valleys wind their way among the craters.
00:26:29Nirgal Valley, named after the Babylonian war god, is a thousand kilometers long and a billion years old.
00:26:37There seems to have been a time when Mars was much warmer and wetter than it is today.
00:26:42I wonder if life ever arose in the muddy backwaters of these great river systems.
00:26:52The waters flowed at the same time that the great volcanoes of the Tharsis Plateau were made.
00:26:59Before the present continents of Earth were formed, it was a very lively epoch on Mars.
00:27:09Equally old is the Mariner Valley, a strange, vast, mist-filled chasm.
00:27:15If it were on Earth, it would stretch from New York to Los Angeles.
00:27:20Landslides and avalanches are slowly eroding its walls, which collapse to the floor of the valley.
00:27:26There, the winds remove the particles and create immense sand dune fields.
00:27:33Signs of high winds are all over Mars.
00:27:36Often craters have, trailing behind them, long streaks of brighter dark material blown out by the winds.
00:27:43Natural weather veins on the Martian surface.
00:27:47For the sand to be blown about in the thin Martian atmosphere, the winds have to be very fast,
00:27:53sometimes approaching half the speed of sound.
00:27:57But some of the patterns are so odd and intricate that we cannot be sure they're caused by wind-blown sand.
00:28:05And there are other strange markings.
00:28:09Furrowed ground, almost resembling a giant ploughed field a billion years old.
00:28:14And one of the strangest features on Mars, the pyramids of Elysium.
00:28:21Ten times taller than the pyramids of Egypt.
00:28:24Perhaps they're only mountains sculpted by the fierce winds.
00:28:27But perhaps they're something else.
00:28:40How marvelous it would be to glide over the surface of Mars, to fly over Olympus Mons, the largest known volcano in the solar system.
00:28:49The surface area of Mars is exactly as large as the land area of the Earth.
00:28:57It will be a long time before this planet is thoroughly explored.
00:29:02The only canal of Percival Lowell that corresponds to anything real is Mariner Valley.
00:29:085,000 kilometers long, it's a little hard to miss even from Earth.
00:29:14The Grand Canyon of Arizona would fit into one of its minor tributaries.
00:29:19Someday, we will careen through the corridors of the Valley of the Mariners.
00:30:03To skim over the sand dunes of Mars is, as yet, only a dream.
00:30:33But we have, in fact, sent robot emissaries to Mars.
00:30:49Their names are Viking 1 and Viking 2.
00:30:54The problem was where to land them.
00:30:59We knew that the volcanoes of Tharsis were too high.
00:31:03The thin Martian atmosphere would not there support our descent parachute.
00:31:08The great Mariner Valley was too rough and unpredictable.
00:31:14The polar camps were too cold for the lander's nuclear power plant to keep it warm.
00:31:19There were fascinating places that were too high or too windy or too hard or too soft or too rough or too cold.
00:31:29We worried about the safety of every landing site.
00:31:33Perhaps we were too cautious.
00:31:36Eventually, we selected two places.
00:31:39One optimistically named Utopia for Viking 2.
00:31:43And another, 8,000 kilometers away, not far from the confluence of four great channels.
00:31:51A landing site for Viking 1 called Crysee.
00:31:56Greek for the land of gold.
00:31:58And so, after a voyage of 100 million kilometers, on July 20th, 1976, Viking 1 landed right on target in the Crysee plane.
00:32:16It was less than 80 years since Robert Goddard had his epiphanal vision in a cherry tree in Massachusetts.
00:32:38After hibernating for a year during its interplanetary passage,
00:32:42Viking reawakened on another world.
00:32:48The first thing it did was to call home, reporting a safe arrival.
00:32:55It began to rouse itself, according to instructions memorized months earlier.
00:33:01First, it put out a finger to test the Martian winds.
00:33:06Then, flexing its arm, it flung off a protective glove.
00:33:12Next, Viking prepared to sniff the air and taste the soil.
00:33:20Finally, it opened its eyes for a look at its new surroundings.
00:33:32Viking's first picture assignment was to photograph its own foot.
00:33:36In case Viking were to sink into Martian quicksand, we wanted to know about it before it disappeared.
00:33:43Back on Earth, we waited breathlessly for the first images.
00:33:47Viking painted its picture in vertical strokes, line by line,
00:33:52until with enormous relief, we saw the footpad securely planted in the Martian soil.
00:33:57This was the first image ever returned from the surface of Mars.
00:34:08The cameras on each Viking lander revealed a kind of rocky desert.
00:34:14Beyond the lander itself, we saw for the first time the landscape of the Red Planet.
00:34:19It didn't look like an alien world.
00:34:24There were rocks and sand dunes and gently rolling hills as natural and familiar as any landscape on Earth.
00:34:34Forever after, Mars would be a place.
00:34:38We found that the Martian air was less than 1% as dense as ours, and made mostly of carbon dioxide.
00:34:51There were smaller amounts of nitrogen, argon, water vapor, and oxygen.
00:34:56And there was almost no ozone, so the surface was not protected from the sun's ultraviolet light, as it is on Earth.
00:35:02On the warmest days, it was distinctly chilly.
00:35:07And every night, the temperatures plunged to 100 below.
00:35:12In winter, the surface was dusted with a thin layer of frost.
00:35:20The landing sites were chosen because they were safe and flat.
00:35:25Even so, Viking revolutionized our knowledge of this rusty world.
00:35:32I would, of course, have been surprised to see a grizzled prospector emerge from behind a dune, leading his mule.
00:35:40Yet, the idea seemed strangely appropriate.
00:35:45But at least while we were watching, no prospector wandered by.
00:35:50We studied with exceptional care every picture of the cameras radioed back.
00:36:00But there was no hint of the canals of Barsoom.
00:36:04No sultry princesses.
00:36:06No ten-foot-tall green fighting men.
00:36:10No thoats.
00:36:12No footprints.
00:36:13Not even a cactus or a kangaroo rat.
00:36:15But perhaps there was life inside the rocks or under the ground.
00:36:22If so, it had left no traces.
00:36:32For most of its history, the Earth had microbes, but no living things big enough to see.
00:36:38Perhaps the same is true for Mars.
00:36:42The Viking Lander is a superbly instrumented and designed machine.
00:37:05It extends human capabilities to other and alien landscapes.
00:37:10By some standards, it's about as smart as a grasshopper.
00:37:15By others, only as intelligent as a bacterium.
00:37:18There's nothing demeaning in these comparisons.
00:37:20It took nature hundreds of millions of years to evolve a bacterium.
00:37:25And billions of years to make a grasshopper.
00:37:28With only a little experience in this sort of business, we're getting pretty good at it.
00:37:32In both landing sites, in Crisee and Utopia, we've begun to dig the sands of Mars.
00:37:43On a very small scale, such trenches are the first human engineering works on another world.
00:37:49The robot arm retrieves soil samples and deposits them into several sifters.
00:38:07Then, the soil is carried to five experiments, two in the chemistry of the soil, and three to look for microbial life.
00:38:17The Viking biology experiments represent a pioneering first effort in the search for life on another world.
00:38:25The results are tantalizing, annoying, provocative, stimulating, and deeply ambiguous.
00:38:32By criteria established before launch, two of the three Viking microbiology experiments seem to have yielded positive results.
00:38:44First, when Martian soil samples are mixed together with an organic soup from Earth,
00:38:51something in the soil seems to have broken the food down,
00:38:54almost as if there were little Martian microbes which metabolized, enjoyed, the soup from Earth.
00:39:04Second, when gases from Earth were mixed together with Martian soil,
00:39:10something seems to have chemically combined the gases with the soil,
00:39:14almost as if there were little Martian microbes capable of synthesizing organic matter from atmospheric gases.
00:39:23But the situation is complex.
00:39:24Mars is not the Earth, as the legacy of Percival Lowell reminds us we are liable to be fooled.
00:39:32Perhaps the ultraviolet light from the sun strikes the Martian surface
00:39:37and makes some chemical which can oxidize foodstuffs.
00:39:43Perhaps there is some catalyst in the Martian soil
00:39:46which can combine atmospheric gases with the soil and make organic molecules.
00:39:51The red sands of Mars were excavated seven times at the two different landing sites as distant from each other as Boston is from Baghdad.
00:40:02Whatever was giving these results was probably all over Mars,
00:40:07but was it life or just the chemistry of the soil?
00:40:11Studies suggest that a kind of clay known to exist on Mars can serve as a catalyst
00:40:17to accelerate in the absence of life chemical reactions which resemble the activities of life.
00:40:23It may be that in the early history of the Earth, before life,
00:40:29there were little cycles, chemical cycles, running in the soil,
00:40:34something like photosynthesis and respiration,
00:40:37which were then incorporated by biology once life arose.
00:40:41There may be life elsewhere than in the two small sites we examined,
00:40:47or perhaps there's life of a different sort all over Mars.
00:40:52Life is just a kind of chemistry of sufficient complexity to permit reproduction and evolution.
00:40:59I wonder if we'll ever find a specimen of life based not on organic molecules,
00:41:04but on something else, something more exotic.
00:41:07The Viking experiments found that the Martian soil is not looted with organic remains of once-living creatures.
00:41:20Maybe the reactive chemistry of the surface has destroyed organic molecules,
00:41:25molecules based on carbon.
00:41:27Or maybe there's no life on Mars and all Vikings found was a funny soil chemistry.
00:41:32Or maybe there's life okay, but it's not based on organic chemistry as much as life is on Earth.
00:41:40Personally, I don't think that's a very likely possibility.
00:41:44I'm a carbon chauvinist.
00:41:46I freely admit it.
00:41:48Carbon is tremendously abundant in the cosmos,
00:41:51and it makes marvelously complex organic molecules that are terrifically good for life.
00:41:56I'm also a water chauvinist.
00:41:59It's an ideal solvent for organic molecules,
00:42:02and it stays liquid over a very wide range of temperatures.
00:42:06But sometimes I wonder,
00:42:09could my fondness for these materials have anything to do with the fact that I'm chiefly made up of them?
00:42:16Are we carbon and water based because these materials were abundant on the early Earth at the time of the origin of life?
00:42:24Might life elsewhere be based on different stuff?
00:42:27I'm a collection of organic molecules called Carl Sagan.
00:42:35You're a collection of almost identical molecules with a different collective label.
00:42:40But is that all?
00:42:43Is there nothing in here but molecules?
00:42:47Some people find that idea somehow demeaning to human dignity.
00:42:53But for myself, I find it elevating and exhilarating to discover that we live in a universe
00:43:00which permits the evolution of molecular machines as intricate and subtle as we.
00:43:07The essence of life is not so much the atoms and small molecules that go into us
00:43:13as the way, the ordering, the way those molecules are put together.
00:43:19Now, we sometimes read that the chemicals which make up a human body are worth on the open market only 97 cents or $10 or some number like that.
00:43:29And it's depressing to find our bodies valued at so little, but these estimates are, for humans, reduced to our simplest possible components.
00:43:40What is all this stuff in front of me?
00:43:46These are exactly the atoms that make up the human body and in the right proportions, too.
00:43:53We're made mostly of water, and that costs almost nothing.
00:43:58The carbon is counted as coal, the calcium in our bones is chalk, the nitrogen in our proteins is liquid air,
00:44:08the iron in our blood is rusty nails, some phosphorus and some trace elements.
00:44:14If we didn't know better, we might be tempted to take all these items and mix them together in a container like this.
00:44:28And stir.
00:44:49We could stir all we want, and at the end of it, all we'd have is some boring mixture of atoms.
00:44:54How could we have expected anything else?
00:44:56The beauty of a living thing is not the atoms that go into it, but the way those atoms are put together,
00:45:03information distilled over 4 billion years of biological evolution.
00:45:08Incidentally, all the organisms on the Earth are made essentially of that stuff.
00:45:13An eyedropper full of that liquid could be used to make a caterpillar or a petunia,
00:45:21if only we knew how to put the components together.
00:45:23All life on Earth is made from the same mixture of the same atoms.
00:45:30On another planet, the jars of life might be filled with very different atoms and small molecules,
00:45:36but I think the life forms on many worlds will consist, by and large, of the same atoms that are popular here,
00:45:43or maybe even the same big molecules.
00:45:45So I don't believe we can rescue the idea of life on Mars by appealing to some exotic chemistry.
00:45:53Sometimes we hear about possible life forms in which silicon replaces carbon,
00:46:00or perhaps liquid ammonia replaces liquid water.
00:46:04But at Martian temperatures, there don't seem to be any plausible silicon-based molecules
00:46:08which might carry a genetic code.
00:46:10Some day in the distant future, we might have a collection of jars,
00:46:22each containing the elementary biochemistry of another world.
00:46:26I don't know if there'll be one labeled Mars,
00:46:29but if there is, I bet it will be full of organic molecules.
00:46:39But there's another way to search for life on Mars,
00:46:42to seek out the discoveries and delights which that heterogeneous environment promises us.
00:46:48One of the things that a grasshopper can do, but Viking can't, is move.
00:46:53We landed in the dull places on Mars.
00:46:56For all the solid scientific findings and tantalizing hints which Viking provided,
00:47:01we know that there are an enormous number of places on the planet far more interesting.
00:47:06What we need is a roving vehicle with advanced experiments in biology and organic chemistry,
00:47:12able to land in the safe but dull places and wander to the interesting places.
00:47:23This roving vehicle was developed by the Rensselaer Polytechnic Institute.
00:47:34It has a long list of dumb things it knows not to do.
00:47:37A Mars rover hasn't got time to ask whether it should attempt a steep slope.
00:47:42Radio waves traveling at the speed of light take about 20 minutes for the round trip to Earth.
00:47:47By the time it got an answer, it might be a heap of twisted metal at the bottom of a canyon.
00:47:53A rover has to think for itself.
00:48:01Imagine a rover with laser eyes like this one,
00:48:05but packed with sophisticated biological and chemical instruments,
00:48:09with sampler arms, microscopes and television cameras,
00:48:12wandering over the Martian landscape.
00:48:17It could drive to its own horizon every day.
00:48:20A distant feature it barely resolves at sunrise.
00:48:24It can be sniffing and tasting by nightfall.
00:48:29Billions of people could watch the unfolding adventure on their television sets
00:48:38as the rover explores the ancient river bottoms
00:48:41or cautiously approaches the enigmatic pyramids of Elysium.
00:48:46A new age of discovery would have begun.
00:48:50Most of the human species would witness the exploration of another world.
00:49:05Only 80 years ago we could come no closer to Mars
00:49:08than straining to see a tiny shimmering image through a telescope in Arizona.
00:49:14Now, our instruments have actually touched down on the planet.
00:49:19Viking is a legacy of H.G. Wells and Percival Lowell, Robert Goddard.
00:49:26Science is a collaborative enterprise spanning the generations.
00:49:31When it permits us to see the far side of some new horizon,
00:49:35we remember those who prepared the way, seeing for them also.
00:49:40On each lander, there is a micro dot on which is written very small
00:49:48the names of 10,000 men and women responsible for Viking's splendid achievement.
00:49:53One of the names in this micro dot belonged to a friend of mine,
00:49:57a remarkable microbiologist named Wolf Vishniak.
00:50:01He was the first person to build a machine to look for microbes on another world.
00:50:06His friends called it the wolf trap.
00:50:10It contained a liquid nutrient to which Martian soil would be added,
00:50:16and any microbes that liked the food would grow in that nutrient medium and cloud it.
00:50:21The wolf trap was selected to go with Viking to Mars,
00:50:25but NASA is especially vulnerable to budget cuts,
00:50:29and the wolf trap was removed as an economy measure.
00:50:32It was a terrible blow to Vishniak.
00:50:35He'd worked 12 years on it.
00:50:37Others might have stalked off the project,
00:50:40but Vishniak was a gentle and dedicated man.
00:50:44He decided instead to study the most Mars-like environment on this planet,
00:50:49the dry valleys of Antarctica, which were long thought to be lifeless.
00:50:53But Vishniak believed that if he could find microbes growing in these arid polar wastes,
00:51:05the chances of life on Mars would improve.
00:51:12So in November 1973, Vishniak was left in a remote valley in the Asgard mountains of Antarctica.
00:51:20He set up hundreds of little sample collectors,
00:51:25simple versions of the Viking microbiology experiments.
00:51:29On December 10th, he left camp to retrieve some samples and never returned.
00:51:35He had wandered to an unexplored area, apparently slipped on the ice, and fell more than 100 meters.
00:51:43Maybe something had caught his eye.
00:51:46A likely habitat for microbes or a patch of green where none should be.
00:51:52The last entry in his notebook was station 202 retrieved,
00:51:5820 to 30 hours, soil temperature minus 10 degrees, air temperature minus 16 degrees.
00:52:06It had been a typical summer temperature for Mars.
00:52:13Some of his soil samples were later returned,
00:52:16and Vishniak's colleagues discovered that there really is life in the dry valleys of Antarctica,
00:52:21that life is even more tenacious than we had imagined.
00:52:25That fact may turn out to be very important for the future history of Mars.
00:52:36There will be a time when Mars is thoroughly explored.
00:52:40What then? What should we do with Mars?
00:52:44If there is life on Mars, then I believe we should do nothing to disturb that life.
00:52:50Mars, then, belongs to the Martians even if they are microbes.
00:52:56But suppose that Mars is in fact lifeless.
00:52:59Might we, in some sense, be able to live there to somehow make Mars habitable like the Earth,
00:53:06to terraform another world?
00:53:12As lovely a world as Mars is, it poses certain problems for us.
00:53:17There's too little oxygen, no liquid water, and too much ultraviolet light.
00:53:22But all that could be solved if we could make more air.
00:53:26With higher atmospheric pressures, liquid water would become possible.
00:53:30With more oxygen, we might be able to breathe the atmosphere,
00:53:34and ozone could form to shield the surface from the solar ultraviolet light.
00:53:39The evidence for past liquid water suggests that Mars once had a denser atmosphere,
00:53:45which can't have all escaped to space.
00:53:48It has to be on the planet somewhere.
00:53:50In subsurface ice, surely, but most excessively, in the present polar caps.
00:53:59To vaporize the ice caps, we must heat them.
00:54:02Preferably by covering them with something dark to absorb more sunlight.
00:54:07That thing ought also to be cheap and able to make copies of itself.
00:54:12Well, there are such things.
00:54:14We call them plants.
00:54:16We would need to evolve, by artificial selection and genetic engineering,
00:54:21dark plants able to survive the severe Martian environment.
00:54:26Such plants could be seeded on the vast expanse of the Martian polar ice caps,
00:54:32taking root, spreading, giving off oxygen, darkening the surface, melting the ice,
00:54:38and releasing the ancient Martian atmosphere from its long captivity.
00:54:43We might even imagine a kind of Martian Johnny Appleseed, robot or human,
00:54:52roaming the frozen polar wastes in an endeavor which benefits only the generations to come.
00:54:59It might take hundreds or thousands of years.
00:55:02We might then want to carry the liberated water from the melting polar ice caps to the warmer equatorial regions.
00:55:16And there's a way to do it.
00:55:18We would build canals.
00:55:21But that's exactly what Percival Lowell believed was in fact happening on Mars in his time.
00:55:27The idea of a canal network built by Martians may turn out to be a kind of premonition.
00:55:34Because if the planet ever is terraformed, it'll be done by human beings
00:55:39whose permanent residence and planetary affiliation is Mars.
00:55:44The Martians will be us.
00:55:57Mars today is strictly relevant to the global environment of the Earth.
00:56:24Its antiseptic surface is a cautionary tale of what happens if you don't have an ozone layer.
00:56:30Its great dust storms and the resulting cooling of its surface played a role in the discovery of nuclear winter,
00:56:37the catastrophic climate change on Earth predicted to follow nuclear war.
00:56:42So if you didn't have an ounce of adventuresome spirit in you,
00:56:45it would still make sense to support the exploration of Mars.
00:56:49In recent years, there's been a groundswell of interest in organizing the first expedition of humans to go to the planet Mars.
00:56:59We first need more robotic missions, including rovers, balloons, and return sample missions,
00:57:07and more experience in long-duration space flight.
00:57:11But eventually, if all goes well, the interplanetary ship or ships would be constructed in Earth orbit,
00:57:17launched on the long journey to Mars, and then a landing module would sit down on the surface.
00:57:25The crew would emerge, making the first human footfalls on another planet.
00:57:32It would be very expensive, of course, although cheaper if many nations share the cost.
00:57:38The key issue in my mind is whether the unmet needs down here on Earth should take priority.
00:57:44But that's a question even more appropriately addressed to the military budgets.
00:57:50Now, one trillion dollars a year worldwide. You can buy a lot for that.
00:57:57Justifications for the Mars endeavor have been offered in terms of scientific exploration,
00:58:03developing technology, international cooperation, education, the environment.
00:58:09Some see it as the obvious response to the future calling.
00:58:13Some even think we should go to investigate enigmatic landforms,
00:58:17including one that resembles an enormous human face.
00:58:20Personally, I think this, like hundreds of other blocky maces there,
00:58:26is sculpted by the high-speed winds.
00:58:28But if we're going anyway, there's no harm in taking a look.
00:58:31A remarkably diverse group of American leaders has endorsed the Mars goal.
00:58:37I imagine the emissaries from Earth, citizens of many nations,
00:58:44wandering down an ancient river valley on Mars,
00:58:47trying to understand how a quite Earth-like world was converted into a permanent ice age
00:58:54and looking for signs of ancient life along the riverbanks.
00:58:59In the long run, the significance of such a mission is nothing less
00:59:03less than the conversion of humanity into a multi-planet species.
00:59:09temper then growing that water vagyis interested in others.
00:59:14There is always a great force of coroner on Mars,
00:59:17leaving the river during the river,
00:59:19using the river behind the river through the river.
00:59:21If there is also a place of raiding in the river that ì•“s,
00:59:23the river is a great way through the river and the river.
00:59:26In the river fashion, it is newlyksi in the river.
00:59:28It is also an excellent place to read the river.
00:59:30The river Ä“s by the river.
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