sagan:martians. why so many speculationsand fantasies about martians... ...rather than saturnians, say,or plutonians? because mars seems,at first glance, very earth-like. it's the nearest planetwhose surface we can see. there are polar icecaps,drifting white clouds... ...raging dust storms,seasonally changing patterns... ...even a 24-hour day. it's tempting to think of itas an inhabited world.
mars has becomea kind of mythic arena... ...onto which we've projectedour earthly hopes and fears. the most tantalizing mythsabout mars have proved wrong. so a few people have swungto the opposite extreme... ...and concluded thatthe planet is of little interest. they've begun to singblues for the red planet. but the real mars isa world of wonders. its future prospects arefar more intriguing... ...than our past apprehensionsabout it.
in our time, we have siftedthe sands of mars... ...established a presence there... ...and fulfilled a century of dreams. the most startling dream of marswas that of h.g. wells... ...who in 1897 wrotethe war of the worlds. narrator: "no one would have believedin the end of the 19th century... ...that this world was beingwatched keenly and closely... ...by intelligencesgreater than man's... ...and yet as mortal as his own.
as men busied themselvesabout their various concerns... ...they were scrutinizedand studied... ...perhaps almostas narrowly as a man... ...with a microscopemight scrutinize... ...the transient creaturesthat swarm and multiply... ...in a drop of water. with infinite complacency,men went to and fro over this globe... ...about their little affairs... ...serene in their assuranceof their empire over matter.
it's possible that the infusoriaunder the microscope do the same. (children singing) no one thought ofthe older worlds of space... ...as sources of human danger... ...or thought of them only to dismissthe idea of life upon them... ...as impossible or improbable. (clapping) it is curious to recall... ...some of the mental habitsof those departed days.
at most, terrestrial men fancied... ...there might be other men upon mars,perhaps inferior to themselves... ...and ready to welcomea missionary enterprise. yet across the gulf of space... ...intellects vastand cool and unsympathetic... ...regarded this earthwith envious eyes... ...and slowly and surelydrew their plans against us." (cheering) sagan: wells' novel capturedthe popular imagination...
...in the late victorian era. this was a time whenthe automobile was a novelty... ...when the pace of life... ...was still determinedby the speed of the horse. into this world, wells introducedan interplanetary fantasy... ...with spaceships, ray gunsand implacable aliens. these were originaland disquieting possibilities. the martians of h.g. wells... ...were not merely minor variationson a human theme.
instead, they werethe evolutionary product... ...of a totally alien environment. forty years later,this fantasy was still able... ...to frighten millionsin war-jittery america... ...when it was dramatized for radioby the young orson welles. a few years beforethe war of the worlds was published... ...another, quite differentvision of martians... ...was forming in the mindof a wealthy bostonian... ...named percival lowell.
the martians of h.g. wellswere a way for the novelist... ...to examine contemporary societythrough alien eyes. but the martians of percival lowellwere, he believed... ...very real. it was here thatthe most elaborate claims... ...in support of life on marswere developed. lowell dabbled in astronomyas a young man. he went off to harvard. he had a semiofficialdiplomatic appointment to korea...
...and otherwise engagedin the usual pursuits... ...of the wealthy for his time. but his lifelong love... ...was the planet mars. lowell was electrified... ...by the announcement in 1877... ...by an italian astronomer,giovanni schiaparelli... ...of canali on mars. schiaparelli had reported...
...during a close approachof mars to the earth... ...an intricate network ofsingle and double straight lines... ...crisscrossingthe bright areas of mars. now, canali in italianmeans "channels" or "grooves"... ...but it was promptly translatedinto english as canals... ...a word which understandably has... ...a certain implicationof intelligent design. a mars-mania swept througheurope and america... ...and percival lowell foundhimself caught up in it.
in 1892, his eyesight failing... ...schiaparelli announcedhe was giving up observing mars. lowell resolvedto continue the work. (roof creaks) he wanteda first-rate observing site... ...undisturbed by cloudsor city lights... ...and marked by good seeing. "seeing" is the astronomer's termfor a steady atmosphere... ...through which the shimmeringof an astronomical image...
...in the telescope is minimized. lowell built his observatoryfar away from home... ...on mars hill,here in flagstaff, arizona. lowell sketchedthe surface features of mars... ...and particularly the canals,which mesmerized him. now, observations of this sortaren't easy. you put in long hoursat the telescope... ...in the chill of the early morning. most of the time,the seeing is crummy.
when the seeing is bad... ...the image of marsblurs and distorts... ...and you have to ignorewhat you've observed. but occasionally the image steadiesand the features of the planet... ...marvelously flash out at you. you must then rememberwhat you've seen... ...and accurately commit it to paper. you must putyour preconceptions aside... ...and with an open mind,set down the wonders...
...that mars holds in store for us. this is percival lowell'sown notebook. here's what he thought he saw. bright and dark areas,a hint of a polar cap... ...and canals.lots and lots of canals. lowell believed... ...that he was seeinga globe-girdling network... ...of great irrigation canals... ...carrying waterfrom the melting polar caps...
...to the thirsty inhabitantsof the equatorial cities. he believedthe planet was inhabited... ...by an older and wiser race... ...perhaps very different from us. he believed... ...that the seasonal changesin the dark areas... ...were due to the growthand decay of vegetation. he believed thatthe planet was earth-like. all in all, he believed too much.
lowell's martians were a dying race. their once-great citieshad fallen into ruins. lowell believed thatthe martian climate was changing... ...that the precious waterwas trickling away into space... ...that the planetwas becoming a desert world. the canals, he thought,were a last desperate measure... ...a heroic engineering effortto conserve the scarce water. but their technology, althoughfar more advanced than ours... ...was inadequate to stema planetary catastrophe.
the most serious contemporarychallenge to lowell's ideas... ...came from an unlikely source: the biologist alfred russel wallace... ...co-discoverer of evolutionby natural selection. wallace correctly showedthat the air on mars... ...was much too cold and thin... ...to permit the existenceof liquid water. he wrote that"only a race of madmen... ...would build canalsunder such conditions."
lowell's martianswere benign and hopeful... ...even a little godlike... ...very differentfrom the malevolent menace... ...posed by h.g. wells and orsonwelles in the war of the worlds. both sets of ideas passedinto the public imagination... ...through sunday supplementsand science fiction... ...and excited generationsof 8-year-olds into fantasizing... ...that they themselvesmight one day voyage... ...to the distant planet mars.
i remember readingwith breathless fascination... ...the mars novelsof edgar rice burroughs. i journeyed with john carter... ...gentleman adventurerfrom virginia... ...to barsoom, as marswas known by its inhabitants. wandering among the beastsof burden called thoats... ...winning the hand ofthe lovely dejah thoris... ...princess of helium... ...and befriendinga 10-foot-high green fighting man...
...named tars tarkas... ...as the moons of marshurtled overhead... ...on a summer's evening on barsoom. it aroused generationsof 8-year-olds... ...myself among them... ...to consider the exploration ofthe planets as a real possibility... ...to wonder whether we ourselvesmight one day venture... john carter got to barsoomby standing in an open field... ...spreading his handsand wishing hard at mars.
i can remember spendingmany an hour in my boyhood... ...arms resolutely outstretched... ...in an open field in twilight... ...imploring what i believedto be mars to transport me there. it never worked. there had to be some better way. and there was.the real road to mars was opened... ...by a boy who loved skyrockets. (band plays)
fourth of july celebrationsin new england... ...are much the same todayas they were in the 1890s. then, as now, the highlightof the day's festivities... ...was a rousing fireworks display. that was the part thatrobert goddard liked the best. by the time he was 16,he was launching his own rockets. he wrote in his diary: "july 4, 1898: fired cannonand firecrackers all day.
in evening, had five rockets." - you gonna light it now?- yes, i am. wow! that same year... ...the war of the worlds was beingserialized in the boston post. goddard eagerly read every word. the boston newspaperswere also reporting... ...intriguing conjecturesby a professor lowell... ...whose lecturesgoddard would later attend.
the images of mars spunby wells and lowell... ...beguiled the young goddard... ...and at age 17... ...on october 19, 1899... ...they crystallizedinto an overwhelming vision... ...that provided the directionand purpose of his life. from the high branches... ...of an old cherry treeon his family's farm... ...goddard saw a way to do morethan just speculate about mars.
before anyone had ever flownin an airplane... ...or listened to a radio... ...goddard decidedto invent a machine... ...that would voyageto the planet mars. for the rest of his life, he wasto commemorate that october day... ...as his anniversary day... ...the birthday of his great dream. by the 1920s, after years ofstudying physics and engineering... ...he was experimentingwith liquid fuel rockets.
in order to build a rocket capableof reaching high altitudes... ...goddard had to create the principlesof an entirely new technology. he invented the basic components... ...that propel, stabilize... ...and guide the modern rocket. it was painstaking and difficult work. but goddard tookthe many setbacks in stride. he sifted the wreckageof each experiment... ...for clues to guide the next.
constantly refining old techniquesand inventing new ones... ...he gradually raised the rocketfrom a dangerous toy... ...and set it on its way to becomingan interplanetary vehicle. goddard died in 1945... ...before a rocket had everleft the planet earth. although mars alwaysremained his objective... ...goddard knew that such a goalwould be ridiculed. in public he advocatedthe more modest objective... ...of flying to the moon.
those boyhood dreams of voyagesto the moon and mars... ...shared by goddardwith his contemporary... ...a russian scientist namedkonstantin tsiolkovsky... ...were fulfilled onlya few decades after their deaths. but as it turned out, the firstplanet to be explored by rocket... ...was the earth. now, imagine yourself a visitor... ...from some otherand quite alien planet. you approach the earthwith no preconceptions.
is the place inhabited?at what point can you decide? when we look at the whole earth,there are no signs of life. we must examine it more closely. if there are intelligent beings,maybe they create structures... ...which can be seen ata resolution of a few kilometers. yet at this level of detail... ...even a great river valleyseems utterly lifeless. there is no sign of life... ...intelligent or otherwisein washington, d. c...
...or moscow... ...or tokyo... ...or peking. if there are intelligent beings,they have not much modified... ...the landscape into geometricalpatterns at kilometer resolution. but when we improvethe resolution tenfold... ...when we see detailas small as 100 meters across... ...the size of a football field... ...the situation changes.
many places on earth seem suddenlyto crystallize out... ...revealing an intricate patternof straight lines... ...squares, rectangles and circles. canals, roads,circular irrigation patterns... ...all suggest intelligent lifewith a passion... ...for euclidean geometryand territoriality. on this scale,intelligent life can be discerned. boston... ...and washington...
...and new york. at 10-meter resolution, we alsodiscover that the earthlings... ...like to build up. at twilight or night,other things are visible: oil well fires in the persian gulf... ...or the bright lightsof large cities. at a meter resolution,we make out individual organisms: seals on ice floes... ...or people on skis.
intelligent life on earthfirst reveals itself... ...through the geometric regularityof its constructions. if lowell's canal network existed,the conclusion that... ...intelligent beings inhabitthat planet might be compelling. but there is no canal network. our unmanned spacecrafthave examined mars... ...with 1000 times more detail... ...than any fleeting glimpse availablethrough percival lowell's telescope. there is no question that his martiancanals were of intelligent origin.
the only question was... ...which side of the telescopethe intelligence was on. where we have strong emotions,we are liable to fool ourselves. yet even without the canals,the exploration of mars evokes... ...the kind of rapture that... ...columbus or marco polomust have felt. we see many impact craters... ...but we find no canals.none at all. there are fault linesin the surface...
...and complex patternsof ridges and valleys... ...but they're all far too smalland in the wrong places... ...to be lowell's canals. and they don't seemto be manufactured. there are many signs of water. ancient river valleys windtheir way among the craters. nergal valley, namedafter the babylonian war god... ...is 1000 kilometers longand a billion years old. there seems to have been a time...
...when mars was warmerand wetter than it is today. i wonder if life ever arose... ...in the muddy backwatersof these great river systems. the waters flowed at the same time... ...that the great volcanoesof the tharsis plateau were made. before the present continentsof earth were formed... ...it was a very lively epoch on mars. equally old is the mariner valley... ...a strange, vast, mist-filled chasm.
if it were on earth, it would stretchfrom new york to los angeles. landslides and avalanchesare slowly eroding its walls... ...which collapseto the floor of the valley. there, the winds removethe particles... ...and create immensesand dune fields. signs of high winds are all over mars. often craters have,trailing behind them... ...long streaks of bright or darkmaterial, blown out by the winds... ...natural weathervaneson the martian surface.
for the sand to be blown aboutin the thin martian atmosphere... ...the winds have to be fast... ...sometimes approachinghalf the speed of sound. but some of the patternsare so odd and intricate... ...that we cannot be surethey're caused by windblown sand. and there are other strange markings: furrowed ground, almost resembling... ...a giant plowed fielda billion years old... ...and one of the strangestfeatures on mars...
...the pyramids of elysium... ...10 times tallerthan the pyramids of egypt. perhaps they're only mountainssculpted by the fierce winds... ...but perhaps they're something else. how marvelous it would beto glide over the surface of mars... ...to fly over olympus mons... ...the largest known volcanoin the solar system. the surface area of marsis exactly... ...as large asthe land area of the earth.
it will be a long time beforethis planet is thoroughly explored. the only canal of percival lowellthat corresponds to anything real... ...is mariner valley. 5000 kilometers long... ...it's a little hardto miss even from earth. the grand canyonof arizona would fit... ...into one of its minor tributaries. someday we will careenthrough the corridors... ...of the valley of the mariners.
to skim overthe sand dunes of mars is... ...as yet, only a dream. but we have, in fact... ...sent robot emissaries to mars. their names are viking 1... ...and viking 2. the problem was where to land them. we knew that the volcanoesof tharsis were too high. the thin martian atmospherewould not...
...support our descent parachute. the great mariner valley wastoo rough and unpredictable. the polar caps were too cold... ...for the lander's nuclearpower plant to keep it warm. there were fascinating placesthat were too high... ...or too windyor too hard or too soft... ...or too rough or too cold. we worried about the safetyof every landing site. perhaps we were too cautious.
eventually we selected two places. one, optimistically named utopia... ...for viking 2... ...and another,8000 kilometers away... ...not far from the confluentsof four great channels... ...a landing site for viking 1... ...called chryse... ...greek for "the land of gold." and so, after a voyageof 100 million kilometers...
...on july 20, 1976... ...viking 1 landed right on target... ...in the chryse plain. it was less than 80 yearssince robert goddard... ...had his epiphanic vision... ...in a cherry tree in massachusetts. after hibernating for a yearduring its interplanetary passage... ...viking reawakened on another world. the first thing it didwas to call home...
...reporting a safe arrival. it began to rouse itself... ...according to instructionsmemorized earlier. first, it put out a fingerto test the martian winds. then, flexing its arm... ...it flung off a protective glove. next, viking preparedto sniff the air... ...and taste the soil. finally...
...it opened its eyes for a lookat its new surroundings. (whirring) viking's first picture assignmentwas to photograph its own foot. in case it were to sinkinto martian quicksand... ...we wanted to know about itbefore it disappeared. back on earth, we waitedbreathlessly for the first images. viking painted its picturein vertical strokes, line by line... ...until, with enormous relief,we saw the footpad... ...securely plantedin the martian soil.
this was the first imageever returned from the surface of mars. the cameras on eachviking lander revealed... ...a kind of rocky desert. beyond the lander itself... ...we saw for the first time... ...the landscape of the red planet. it didn't look like an alien world. there were rocks and sand dunes... ...and gently rolling hillsas natural and familiar...
...as any landscape on earth. forever after, mars would be a place. we found that the martian airwas less than 1% as dense as ours... ...and made mostly of carbon dioxide. there were smaller amountsof nitrogen, argon... ...water vapor and oxygen. there was almost no ozone.so the surface wasn't protected... ...from the sun's ultraviolet lightas it is on earth. on the warmest days,it was distinctly chilly...
...and every night the temperaturesplunged to 100 below. in winter, the surface was dustedwith a thin layer of frost. the landing sites were chosenbecause they were safe and flat. even so, viking revolutionizedour knowledge... ...of this rusty world. i would, of course, have beensurprised to see... ...a grizzled prospector emergefrom behind a dune... ...leading his mule. yet the idea seemedstrangely appropriate.
but at least while we were watching... ...no prospector wandered by. we studied with exceptional careeach picture the cameras radioed back. but there was no hintof the canals of barsoom... ...no sultry princesses... ...no 10-foot-tallgreen fighting men... ...no thoats, no footprints... ...not even a cactusor a kangaroo rat. perhaps there was lifeinside the rocks...
...or under the ground. if so, it had left no traces. for most of its history,the earth had microbes... ...but no living thingsbig enough to see. perhaps the same is true for mars. the viking lander is a superblyinstrumented and designed machine. it extends human capabilitiesto other and alien landscapes. by some standards, it's aboutas smart as a grasshopper. by others, only as intelligentas a bacterium.
there's nothing demeaningin these comparisons. it took nature hundreds of millionsof years to evolve a bacterium... ...and billions of yearsto make a grasshopper. with only a little experiencein this business... ...we're getting pretty good at it. in both landing sites... ...in chryse and utopia... ...we've begun to digin the sands of mars. on a very small scale,such trenches...
...are the first human engineeringworks on another world. the robot armretrieves soil samples... ...and deposits theminto several sifters. then the soil is carriedto five experiments: two on the chemistry of the soil... ...and three to lookfor microbial life. the viking biology experimentsrepresent a pioneering first effort... ...in the search for lifeon another world. the results aretantalizing, annoying...
...provocative, stimulating... ...and deeply ambiguous. by criteria establishedbefore a launch... ...two of the three vikingmicrobiology experiments... ...seem to have yieldedpositive results. first, when martian soil samplesare mixed together... ...with an organic soup from earth... ...something in the soilseems to have broken food down... ...almost as if there werelittle martian microbes...
...which metabolized, enjoyed... ...the soup from earth. second, when gases from earth... ...were mixed togetherwith martian soil... ...something seems to have chemicallycombined the gases with soil... ...almost as if there were littlemartian microbes capable... ...of synthesizing organic matterfrom atmospheric gases. but the situation is complex. mars is not the earth.
as the legacy of percival lowellreminds us, we're liable to be fooled. perhaps the ultraviolet lightfrom the sun... ...strikes the martian surface... ...and makes some chemicalwhich can oxidize foodstuffs. perhaps there is some catalystin the soil... ...which can combine atmospheric gaseswith the soil... ...and make organic molecules. the red sands of marswere excavated... ...seven times atthe two different landing sites...
...as distant from each otheras boston is from baghdad. whatever was giving these resultswas probably all over mars... ...but was it life, or justthe chemistry of the soil? studies suggest that a kind of clayknown to exist on mars... ...can serve as a catalyst toaccelerate in the absence of life... ...chemical reactions whichresemble the activities of life. it may be that in the early historyof the earth, before life... ...there were little cycles,chemical cycles running in the soil... ...something like photosynthesisand respiration...
...which were then incorporatedby biology once life arose. there may be life elsewhere thanin the two small sites we examined. or perhaps there's lifeof a different sort all over mars. life is just a kind of chemistryof sufficient complexity... ...to permit reproductionand evolution. i wonder if we'll ever finda specimen of life based... ...not on organic molecules... ...but on something else,something more exotic. the viking experiments foundthat the martian soil is not...
...loaded with organic remains... ...of once living creatures. maybe the surface's reactive chemistryhas destroyed organic molecules... ...molecules based on carbon. or maybe there's no life on mars... ...and all viking foundwas a funny soil chemistry. or maybe there's life, okay... ...but it's not based on organicchemistry as much as life is on earth. personally, i don't think that'sa very likely possibility.
i'm a carbon chauvinist.i freely admit it. carbon is tremendously abundantin the cosmos... ...and it makes marvelously complexorganic molecules... ...that are terrificallygood for life. i'm also a water chauvinist. it's an ideal solventfor organic molecules... ...and it stays liquid overa very wide range of temperatures. but sometimes i wonder,could my fondness... ...for these materials haveanything to do with the fact...
...that i'm chiefly made up of them? are we carbon and water-based becausethese materials were abundant... ...on the earth at the timeof the origin of life? might life elsewhere be basedon different stuff? (liquid gurgles) i'm a collection of organic moleculescalled carl sagan. you're a collection of almostidentical molecules... ...with a different collective label.but is that all? is there nothing in herebut molecules?
some people find that ideasomehow demeaning to human dignity. but for myself, i find itelevating and exhilarating... ...to discover that welive in a universe... ...which permits the evolutionof molecular machines... ...as intricate and subtle as we. the essence of life is not the atomsand small molecules that go into us... ...as the way, the ordering... ...the way those moleculesare put together. now, we sometimes read...
...that the chemicals which make upa human body are worth... ...on the open market, only 97 centsor $10, or some number like that. and it's depressing to findour bodies valued at so little. but these estimates are for humans... ...reduced to our simplestpossible components. what is all this stuff in front of me? these are exactly the atomsthat make up the human body... ...and in the right proportions too. we're made mostly of water,and that costs almost nothing.
the carbon is counted as coal. the calcium in our bones is chalk. the nitrogen in our proteinsis liquid air. the iron in our bloodis rusty nails. some phosphorusand some trace elements. if we didn't know better... ...we might be temptedto take all these items... ...and mix them togetherin a container like this. and stir.
we could stir all we want... ...and at the end, all we'd haveis some boring mixture of atoms. how could we expect anything else? the beauty of a living thingis not the atoms that go into it... ...but the way those atomsare put together: information distilled over 4 billionyears of biological evolution. incidentally, all the organismson the earth are made... ...essentially of that stuff. an eyedropper full of that liquid...
...could be used to makea caterpillar or a petunia... ...if only we knew how to putthe components together. all life on earth is made fromthe same mixture of the same atoms. on another planet, the jars of life... ...might be filled with verydifferent atoms and small molecules. but i think the life forms on manyworlds will consist, by and large... ...of the same atomsthat are popular here... ...maybe even the same big molecules. so i don't believe we can rescuethe idea of life on mars...
...by appealing to someexotic chemistry. sometimes we hear aboutpossible life forms... ...in which silicon replaces carbon... ...or perhaps, liquid ammoniareplaces liquid water. but at martian temperatures,there are no... ...plausible silicon-based moleculeswhich might carry a genetic code. and ammonia is liquidonly under higher pressures... ...and lower temperatures. someday in the distant futurewe might have a collection of jars...
...each containing the elementarybiochemistry of another world. i don't know if there'll beone labeled "mars." but if there is... ...i bet it will befull of organic molecules. there's another way to searchfor life on mars... ...to seek out the discoveriesand delights... ...which that heterogeneousenvironment promises us. one of the things that a grasshoppercan do but viking can't... ...is move.
we landed in the dull places on mars. for all the solid, scientific findingsand hints which viking provided... ...we know that there are many placeson the planet far more interesting. what we need is a roving vehicle... ...with advanced experiments inbiology and organic chemistry... ...able to land in the safebut dull places... ...and wanderto the interesting places. this roving vehicle... ...was developed by therensselaer polytechnic institute.
it has a long list of dumb thingsit knows not to do. a mars rover hasn't got time to askif it should attempt a steep slope. radio waves travelingat the speed of light... ...take 20 minutesfor the roundtrip to earth. by the time it got an answer,it might be... ...a heap of twisted metalat the bottom of a canyon. a rover has to think for itself. imagine a rover with laser eyeslike this one... ...but packed with sophisticatedbiological and chemical instruments...
...sampler arms, microscopesand television cameras... ...wandering overthe martian landscape. it could drive to its ownhorizon every day. a distant feature it barelyresolves at sunrise... ...it can be sniffing and tastingby nightfall. billions of people could watchthe unfolding adventure... ...on their tv sets as the roverexplores the ancient river bottoms... ...or cautiously approaches... ...the enigmatic pyramids of elysium.
a new age of discoverywould have begun. most of the human specieswould witness... ...the exploration of another world. only 80 years ago, we could comeno closer to mars... ...than straining to seea tiny, shimmering image... ...through a telescope in arizona. now our instruments have actuallytouched down on the planet. viking is a legacy of h.g. wells... ...percival lowell, robert goddard.
science is a collaborative enterprisespanning the generations. when it permits us to see the far sideof some new horizon... ...we remember thosewho prepared the way... ...seeing for them also. on each lander, there is a microdoton which is written very small... ...the names of 10,000men and women... ...responsible for viking'ssplendid achievement. one of the names on this microdotbelonged to a friend of mine: a remarkable microbiologistnamed wolf vishniac.
he was the first personto build a machine... ...to look for microbeson another world. his friends called it the "wolf trap." it contained a liquid nutrient... ...to which martian soilwould be added... ...and any microbesthat liked the food... ...would grow in that nutrientmedium and cloud it. the wolf trap was selectedto go with viking to mars... ...but nasa is especially vulnerableto budget cuts...
...and it was removedas an economy measure. it was a terrible blow to vishniac.he'd worked 12 years on it. others might havestalked off the project... ...but vishniac was a gentleand dedicated man. he decided instead to study the mostmars-like environment on this planet: the dry valleys of antarctica,which were long thought to be lifeless. but vishniac believed that if hecould find microbes growing... ...in these arid polar wastes... ...the chances of life on marswould improve.
so in november 1973... ...vishniac was leftin a remote valley... ...in the asgard mountainsof antarctica. he set up hundreds of littlesample collectors... ...simple versions of the vikingmicrobiology experiments. on december 10th... ...he left campto retrieve some samples... ...and never returned. he had wanderedto an unexplored area...
...apparently slipped on the ice... ...and fell more than 100 meters. maybe something had caught his eye... ...a likely habitat for microbes... ...or a patch of greenwhere none should be. the last entry in his notebook was: "station 202 retrieved.2230 hours. soil temperature, minus 10 degrees. air temperature, minus 16 degrees."
it had been a typicalsummer temperature... ...for mars. some of his soil sampleswere later returned... ...and his colleagues discovered... ...that there is lifein the dry valleys of antarctica... ...that life is even more tenaciousthan we had imagined. that fact may turn out to be importantfor the future history of mars. there will be a time... ...when mars is thoroughly explored.
what then?what should we do with mars? if there is life on mars, then ibelieve we should do nothing... ...to disturb that life. mars, then, belongs to the martians,even if they are microbes. but suppose that mars isin fact lifeless. might we in some sense be ableto live there... ...to somehow make marshabitable like the earth... ...to terraform another world? as lovely a world as mars is...
...it poses certain problems. there's too little oxygen,no liquid water... ...and too much ultraviolet light. but all that could be solvedif we could make more air. with higher atmospheric pressures,liquid water would become possible. with more oxygen we couldbreathe the atmosphere. and ozone could formto shield the surface... ...from the solar ultraviolet light. the evidence for liquid watersuggests...
...that mars once hada denser atmosphere... ...which can't have allescaped to space. it has to be on the planet somewhere. in subsurface ice, surely... ...but most accessiblyin the present polar caps. to vaporize the icecaps,we must heat them... ...preferably by covering them withsomething dark to absorb more sunlight. that thing ought to also be cheapand able to make copies of itself. well, there are such things.we call them plants.
we would need to evolve by artificialselection and genetic engineering... ...dark plants able to survivethe severe martian environment. such plants could be seeded... ...on the vast expanseof the martian polar icecaps... ...taking root, spreading,giving off oxygen... ...darkening the surface,melting the ice... ...and releasingthe ancient martian atmosphere... ...from its long captivity. we might even imagine a kind ofmartian johnny appleseed...
...robot or human... ...roaming the frozen polar wastesin an endeavor which benefits... ...only the generations to come. it might take hundredsor thousands of years. we might, then, want to carrythe liberated water... ...from the melting polar icecaps... ...to the warmer equatorial regions. and there's a way to do it: we would build canals.
but that's exactly whatpercival lowell believed... ...was happening on mars in his time. the idea of a canal networkbuilt by martians... ...may turn out to bea kind of premonition... ...because, if the planetever is terraformed... ...it will be done by human beings... ...whose permanent residenceand planetary affiliation... ...is mars. the martians will be us.
mars today is strictly relevant tothe global environment of the earth. its antiseptic surface isa cautionary tale of what happens... ...if you don't have an ozone layer. its great dust storms and the resultingcooling of its surface... ...played a role in the discoveryof nuclear winter... ...the catastrophic climate change onearth predicted to follow nuclear war. so if you didn't have an ounceof adventuresome spirit in you... ...it would still make senseto support the exploration of mars. in recent years, there's been...
...a groundswell of interest... ...in organizing the first expeditionof humans to go to the planet mars. we first need more robotic missions,including rovers... ...balloons and return-sample missions... ...and more experiencein long duration space flight. but eventually, if all goes well... ...the interplanetaryship or ships... ...would be constructedin earth orbit... ...launched on the longjourney to mars...
...and then a landing modulewould set down on the surface. the crew would emerge... ...making the first human footfallson another planet. it would be very expensive,of course... ...although cheaperif many nations share the cost. the key issue in my mind is whetherthe unmet needs here on earth... ...should take priority. but that's a question even moreappropriately addressed... ...to the military budgets...
...now $1 trillion a year worldwide. you can buy a lot for that. justifications for the mars endeavorhave been offered in terms of... ...scientific exploration... ...developing technology,international cooperation... ...education, the environment. some see it as the obvious responseto the future calling. some even think we should goto investigate enigmatic landforms... ...including one that resemblesan enormous human face.
personally, i think this,like hundreds of other... ...blocky mesas there... ...is sculpted bythe high-speed winds. but if we're going anyway,there's no harm in taking a look. a remarkably diverse groupof american leaders... ...has endorsed the mars goal. i imagine the emissaries from earth... ...citizens of many nations... ...wandering down an ancientriver valley on mars...
...trying to understandhow a quite earth-like world... ...was convertedinto a permanent ice age... ...and looking for signs ofancient life along the river banks. in the long run... ...the significance of such a missionis nothing less... ...than the conversion of humanityinto a multiplanet species.
read also Bilder Schwörer Haus
mars has becomea kind of mythic arena... ...onto which we've projectedour earthly hopes and fears. the most tantalizing mythsabout mars have proved wrong. so a few people have swungto the opposite extreme... ...and concluded thatthe planet is of little interest. they've begun to singblues for the red planet. but the real mars isa world of wonders. its future prospects arefar more intriguing... ...than our past apprehensionsabout it.
in our time, we have siftedthe sands of mars... ...established a presence there... ...and fulfilled a century of dreams. the most startling dream of marswas that of h.g. wells... ...who in 1897 wrotethe war of the worlds. narrator: "no one would have believedin the end of the 19th century... ...that this world was beingwatched keenly and closely... ...by intelligencesgreater than man's... ...and yet as mortal as his own.
as men busied themselvesabout their various concerns... ...they were scrutinizedand studied... ...perhaps almostas narrowly as a man... ...with a microscopemight scrutinize... ...the transient creaturesthat swarm and multiply... ...in a drop of water. with infinite complacency,men went to and fro over this globe... ...about their little affairs... ...serene in their assuranceof their empire over matter.
it's possible that the infusoriaunder the microscope do the same. (children singing) no one thought ofthe older worlds of space... ...as sources of human danger... ...or thought of them only to dismissthe idea of life upon them... ...as impossible or improbable. (clapping) it is curious to recall... ...some of the mental habitsof those departed days.
at most, terrestrial men fancied... ...there might be other men upon mars,perhaps inferior to themselves... ...and ready to welcomea missionary enterprise. yet across the gulf of space... ...intellects vastand cool and unsympathetic... ...regarded this earthwith envious eyes... ...and slowly and surelydrew their plans against us." (cheering) sagan: wells' novel capturedthe popular imagination...
...in the late victorian era. this was a time whenthe automobile was a novelty... ...when the pace of life... ...was still determinedby the speed of the horse. into this world, wells introducedan interplanetary fantasy... ...with spaceships, ray gunsand implacable aliens. these were originaland disquieting possibilities. the martians of h.g. wells... ...were not merely minor variationson a human theme.
instead, they werethe evolutionary product... ...of a totally alien environment. forty years later,this fantasy was still able... ...to frighten millionsin war-jittery america... ...when it was dramatized for radioby the young orson welles. a few years beforethe war of the worlds was published... ...another, quite differentvision of martians... ...was forming in the mindof a wealthy bostonian... ...named percival lowell.
the martians of h.g. wellswere a way for the novelist... ...to examine contemporary societythrough alien eyes. but the martians of percival lowellwere, he believed... ...very real. it was here thatthe most elaborate claims... ...in support of life on marswere developed. lowell dabbled in astronomyas a young man. he went off to harvard. he had a semiofficialdiplomatic appointment to korea...
...and otherwise engagedin the usual pursuits... ...of the wealthy for his time. but his lifelong love... ...was the planet mars. lowell was electrified... ...by the announcement in 1877... ...by an italian astronomer,giovanni schiaparelli... ...of canali on mars. schiaparelli had reported...
...during a close approachof mars to the earth... ...an intricate network ofsingle and double straight lines... ...crisscrossingthe bright areas of mars. now, canali in italianmeans "channels" or "grooves"... ...but it was promptly translatedinto english as canals... ...a word which understandably has... ...a certain implicationof intelligent design. a mars-mania swept througheurope and america... ...and percival lowell foundhimself caught up in it.
in 1892, his eyesight failing... ...schiaparelli announcedhe was giving up observing mars. lowell resolvedto continue the work. (roof creaks) he wanteda first-rate observing site... ...undisturbed by cloudsor city lights... ...and marked by good seeing. "seeing" is the astronomer's termfor a steady atmosphere... ...through which the shimmeringof an astronomical image...
...in the telescope is minimized. lowell built his observatoryfar away from home... ...on mars hill,here in flagstaff, arizona. lowell sketchedthe surface features of mars... ...and particularly the canals,which mesmerized him. now, observations of this sortaren't easy. you put in long hoursat the telescope... ...in the chill of the early morning. most of the time,the seeing is crummy.
when the seeing is bad... ...the image of marsblurs and distorts... ...and you have to ignorewhat you've observed. but occasionally the image steadiesand the features of the planet... ...marvelously flash out at you. you must then rememberwhat you've seen... ...and accurately commit it to paper. you must putyour preconceptions aside... ...and with an open mind,set down the wonders...
...that mars holds in store for us. this is percival lowell'sown notebook. here's what he thought he saw. bright and dark areas,a hint of a polar cap... ...and canals.lots and lots of canals. lowell believed... ...that he was seeinga globe-girdling network... ...of great irrigation canals... ...carrying waterfrom the melting polar caps...
...to the thirsty inhabitantsof the equatorial cities. he believedthe planet was inhabited... ...by an older and wiser race... ...perhaps very different from us. he believed... ...that the seasonal changesin the dark areas... ...were due to the growthand decay of vegetation. he believed thatthe planet was earth-like. all in all, he believed too much.
lowell's martians were a dying race. their once-great citieshad fallen into ruins. lowell believed thatthe martian climate was changing... ...that the precious waterwas trickling away into space... ...that the planetwas becoming a desert world. the canals, he thought,were a last desperate measure... ...a heroic engineering effortto conserve the scarce water. but their technology, althoughfar more advanced than ours... ...was inadequate to stema planetary catastrophe.
the most serious contemporarychallenge to lowell's ideas... ...came from an unlikely source: the biologist alfred russel wallace... ...co-discoverer of evolutionby natural selection. wallace correctly showedthat the air on mars... ...was much too cold and thin... ...to permit the existenceof liquid water. he wrote that"only a race of madmen... ...would build canalsunder such conditions."
lowell's martianswere benign and hopeful... ...even a little godlike... ...very differentfrom the malevolent menace... ...posed by h.g. wells and orsonwelles in the war of the worlds. both sets of ideas passedinto the public imagination... ...through sunday supplementsand science fiction... ...and excited generationsof 8-year-olds into fantasizing... ...that they themselvesmight one day voyage... ...to the distant planet mars.
i remember readingwith breathless fascination... ...the mars novelsof edgar rice burroughs. i journeyed with john carter... ...gentleman adventurerfrom virginia... ...to barsoom, as marswas known by its inhabitants. wandering among the beastsof burden called thoats... ...winning the hand ofthe lovely dejah thoris... ...princess of helium... ...and befriendinga 10-foot-high green fighting man...
...named tars tarkas... ...as the moons of marshurtled overhead... ...on a summer's evening on barsoom. it aroused generationsof 8-year-olds... ...myself among them... ...to consider the exploration ofthe planets as a real possibility... ...to wonder whether we ourselvesmight one day venture... john carter got to barsoomby standing in an open field... ...spreading his handsand wishing hard at mars.
i can remember spendingmany an hour in my boyhood... ...arms resolutely outstretched... ...in an open field in twilight... ...imploring what i believedto be mars to transport me there. it never worked. there had to be some better way. and there was.the real road to mars was opened... ...by a boy who loved skyrockets. (band plays)
fourth of july celebrationsin new england... ...are much the same todayas they were in the 1890s. then, as now, the highlightof the day's festivities... ...was a rousing fireworks display. that was the part thatrobert goddard liked the best. by the time he was 16,he was launching his own rockets. he wrote in his diary: "july 4, 1898: fired cannonand firecrackers all day.
in evening, had five rockets." - you gonna light it now?- yes, i am. wow! that same year... ...the war of the worlds was beingserialized in the boston post. goddard eagerly read every word. the boston newspaperswere also reporting... ...intriguing conjecturesby a professor lowell... ...whose lecturesgoddard would later attend.
the images of mars spunby wells and lowell... ...beguiled the young goddard... ...and at age 17... ...on october 19, 1899... ...they crystallizedinto an overwhelming vision... ...that provided the directionand purpose of his life. from the high branches... ...of an old cherry treeon his family's farm... ...goddard saw a way to do morethan just speculate about mars.
before anyone had ever flownin an airplane... ...or listened to a radio... ...goddard decidedto invent a machine... ...that would voyageto the planet mars. for the rest of his life, he wasto commemorate that october day... ...as his anniversary day... ...the birthday of his great dream. by the 1920s, after years ofstudying physics and engineering... ...he was experimentingwith liquid fuel rockets.
in order to build a rocket capableof reaching high altitudes... ...goddard had to create the principlesof an entirely new technology. he invented the basic components... ...that propel, stabilize... ...and guide the modern rocket. it was painstaking and difficult work. but goddard tookthe many setbacks in stride. he sifted the wreckageof each experiment... ...for clues to guide the next.
constantly refining old techniquesand inventing new ones... ...he gradually raised the rocketfrom a dangerous toy... ...and set it on its way to becomingan interplanetary vehicle. goddard died in 1945... ...before a rocket had everleft the planet earth. although mars alwaysremained his objective... ...goddard knew that such a goalwould be ridiculed. in public he advocatedthe more modest objective... ...of flying to the moon.
those boyhood dreams of voyagesto the moon and mars... ...shared by goddardwith his contemporary... ...a russian scientist namedkonstantin tsiolkovsky... ...were fulfilled onlya few decades after their deaths. but as it turned out, the firstplanet to be explored by rocket... ...was the earth. now, imagine yourself a visitor... ...from some otherand quite alien planet. you approach the earthwith no preconceptions.
is the place inhabited?at what point can you decide? when we look at the whole earth,there are no signs of life. we must examine it more closely. if there are intelligent beings,maybe they create structures... ...which can be seen ata resolution of a few kilometers. yet at this level of detail... ...even a great river valleyseems utterly lifeless. there is no sign of life... ...intelligent or otherwisein washington, d. c...
...or moscow... ...or tokyo... ...or peking. if there are intelligent beings,they have not much modified... ...the landscape into geometricalpatterns at kilometer resolution. but when we improvethe resolution tenfold... ...when we see detailas small as 100 meters across... ...the size of a football field... ...the situation changes.
many places on earth seem suddenlyto crystallize out... ...revealing an intricate patternof straight lines... ...squares, rectangles and circles. canals, roads,circular irrigation patterns... ...all suggest intelligent lifewith a passion... ...for euclidean geometryand territoriality. on this scale,intelligent life can be discerned. boston... ...and washington...
...and new york. at 10-meter resolution, we alsodiscover that the earthlings... ...like to build up. at twilight or night,other things are visible: oil well fires in the persian gulf... ...or the bright lightsof large cities. at a meter resolution,we make out individual organisms: seals on ice floes... ...or people on skis.
intelligent life on earthfirst reveals itself... ...through the geometric regularityof its constructions. if lowell's canal network existed,the conclusion that... ...intelligent beings inhabitthat planet might be compelling. but there is no canal network. our unmanned spacecrafthave examined mars... ...with 1000 times more detail... ...than any fleeting glimpse availablethrough percival lowell's telescope. there is no question that his martiancanals were of intelligent origin.
the only question was... ...which side of the telescopethe intelligence was on. where we have strong emotions,we are liable to fool ourselves. yet even without the canals,the exploration of mars evokes... ...the kind of rapture that... ...columbus or marco polomust have felt. we see many impact craters... ...but we find no canals.none at all. there are fault linesin the surface...
...and complex patternsof ridges and valleys... ...but they're all far too smalland in the wrong places... ...to be lowell's canals. and they don't seemto be manufactured. there are many signs of water. ancient river valleys windtheir way among the craters. nergal valley, namedafter the babylonian war god... ...is 1000 kilometers longand a billion years old. there seems to have been a time...
...when mars was warmerand wetter than it is today. i wonder if life ever arose... ...in the muddy backwatersof these great river systems. the waters flowed at the same time... ...that the great volcanoesof the tharsis plateau were made. before the present continentsof earth were formed... ...it was a very lively epoch on mars. equally old is the mariner valley... ...a strange, vast, mist-filled chasm.
if it were on earth, it would stretchfrom new york to los angeles. landslides and avalanchesare slowly eroding its walls... ...which collapseto the floor of the valley. there, the winds removethe particles... ...and create immensesand dune fields. signs of high winds are all over mars. often craters have,trailing behind them... ...long streaks of bright or darkmaterial, blown out by the winds... ...natural weathervaneson the martian surface.
for the sand to be blown aboutin the thin martian atmosphere... ...the winds have to be fast... ...sometimes approachinghalf the speed of sound. but some of the patternsare so odd and intricate... ...that we cannot be surethey're caused by windblown sand. and there are other strange markings: furrowed ground, almost resembling... ...a giant plowed fielda billion years old... ...and one of the strangestfeatures on mars...
...the pyramids of elysium... ...10 times tallerthan the pyramids of egypt. perhaps they're only mountainssculpted by the fierce winds... ...but perhaps they're something else. how marvelous it would beto glide over the surface of mars... ...to fly over olympus mons... ...the largest known volcanoin the solar system. the surface area of marsis exactly... ...as large asthe land area of the earth.
it will be a long time beforethis planet is thoroughly explored. the only canal of percival lowellthat corresponds to anything real... ...is mariner valley. 5000 kilometers long... ...it's a little hardto miss even from earth. the grand canyonof arizona would fit... ...into one of its minor tributaries. someday we will careenthrough the corridors... ...of the valley of the mariners.
to skim overthe sand dunes of mars is... ...as yet, only a dream. but we have, in fact... ...sent robot emissaries to mars. their names are viking 1... ...and viking 2. the problem was where to land them. we knew that the volcanoesof tharsis were too high. the thin martian atmospherewould not...
...support our descent parachute. the great mariner valley wastoo rough and unpredictable. the polar caps were too cold... ...for the lander's nuclearpower plant to keep it warm. there were fascinating placesthat were too high... ...or too windyor too hard or too soft... ...or too rough or too cold. we worried about the safetyof every landing site. perhaps we were too cautious.
eventually we selected two places. one, optimistically named utopia... ...for viking 2... ...and another,8000 kilometers away... ...not far from the confluentsof four great channels... ...a landing site for viking 1... ...called chryse... ...greek for "the land of gold." and so, after a voyageof 100 million kilometers...
...on july 20, 1976... ...viking 1 landed right on target... ...in the chryse plain. it was less than 80 yearssince robert goddard... ...had his epiphanic vision... ...in a cherry tree in massachusetts. after hibernating for a yearduring its interplanetary passage... ...viking reawakened on another world. the first thing it didwas to call home...
...reporting a safe arrival. it began to rouse itself... ...according to instructionsmemorized earlier. first, it put out a fingerto test the martian winds. then, flexing its arm... ...it flung off a protective glove. next, viking preparedto sniff the air... ...and taste the soil. finally...
...it opened its eyes for a lookat its new surroundings. (whirring) viking's first picture assignmentwas to photograph its own foot. in case it were to sinkinto martian quicksand... ...we wanted to know about itbefore it disappeared. back on earth, we waitedbreathlessly for the first images. viking painted its picturein vertical strokes, line by line... ...until, with enormous relief,we saw the footpad... ...securely plantedin the martian soil.
this was the first imageever returned from the surface of mars. the cameras on eachviking lander revealed... ...a kind of rocky desert. beyond the lander itself... ...we saw for the first time... ...the landscape of the red planet. it didn't look like an alien world. there were rocks and sand dunes... ...and gently rolling hillsas natural and familiar...
...as any landscape on earth. forever after, mars would be a place. we found that the martian airwas less than 1% as dense as ours... ...and made mostly of carbon dioxide. there were smaller amountsof nitrogen, argon... ...water vapor and oxygen. there was almost no ozone.so the surface wasn't protected... ...from the sun's ultraviolet lightas it is on earth. on the warmest days,it was distinctly chilly...
...and every night the temperaturesplunged to 100 below. in winter, the surface was dustedwith a thin layer of frost. the landing sites were chosenbecause they were safe and flat. even so, viking revolutionizedour knowledge... ...of this rusty world. i would, of course, have beensurprised to see... ...a grizzled prospector emergefrom behind a dune... ...leading his mule. yet the idea seemedstrangely appropriate.
but at least while we were watching... ...no prospector wandered by. we studied with exceptional careeach picture the cameras radioed back. but there was no hintof the canals of barsoom... ...no sultry princesses... ...no 10-foot-tallgreen fighting men... ...no thoats, no footprints... ...not even a cactusor a kangaroo rat. perhaps there was lifeinside the rocks...
...or under the ground. if so, it had left no traces. for most of its history,the earth had microbes... ...but no living thingsbig enough to see. perhaps the same is true for mars. the viking lander is a superblyinstrumented and designed machine. it extends human capabilitiesto other and alien landscapes. by some standards, it's aboutas smart as a grasshopper. by others, only as intelligentas a bacterium.
there's nothing demeaningin these comparisons. it took nature hundreds of millionsof years to evolve a bacterium... ...and billions of yearsto make a grasshopper. with only a little experiencein this business... ...we're getting pretty good at it. in both landing sites... ...in chryse and utopia... ...we've begun to digin the sands of mars. on a very small scale,such trenches...
...are the first human engineeringworks on another world. the robot armretrieves soil samples... ...and deposits theminto several sifters. then the soil is carriedto five experiments: two on the chemistry of the soil... ...and three to lookfor microbial life. the viking biology experimentsrepresent a pioneering first effort... ...in the search for lifeon another world. the results aretantalizing, annoying...
...provocative, stimulating... ...and deeply ambiguous. by criteria establishedbefore a launch... ...two of the three vikingmicrobiology experiments... ...seem to have yieldedpositive results. first, when martian soil samplesare mixed together... ...with an organic soup from earth... ...something in the soilseems to have broken food down... ...almost as if there werelittle martian microbes...
...which metabolized, enjoyed... ...the soup from earth. second, when gases from earth... ...were mixed togetherwith martian soil... ...something seems to have chemicallycombined the gases with soil... ...almost as if there were littlemartian microbes capable... ...of synthesizing organic matterfrom atmospheric gases. but the situation is complex. mars is not the earth.
as the legacy of percival lowellreminds us, we're liable to be fooled. perhaps the ultraviolet lightfrom the sun... ...strikes the martian surface... ...and makes some chemicalwhich can oxidize foodstuffs. perhaps there is some catalystin the soil... ...which can combine atmospheric gaseswith the soil... ...and make organic molecules. the red sands of marswere excavated... ...seven times atthe two different landing sites...
...as distant from each otheras boston is from baghdad. whatever was giving these resultswas probably all over mars... ...but was it life, or justthe chemistry of the soil? studies suggest that a kind of clayknown to exist on mars... ...can serve as a catalyst toaccelerate in the absence of life... ...chemical reactions whichresemble the activities of life. it may be that in the early historyof the earth, before life... ...there were little cycles,chemical cycles running in the soil... ...something like photosynthesisand respiration...
...which were then incorporatedby biology once life arose. there may be life elsewhere thanin the two small sites we examined. or perhaps there's lifeof a different sort all over mars. life is just a kind of chemistryof sufficient complexity... ...to permit reproductionand evolution. i wonder if we'll ever finda specimen of life based... ...not on organic molecules... ...but on something else,something more exotic. the viking experiments foundthat the martian soil is not...
...loaded with organic remains... ...of once living creatures. maybe the surface's reactive chemistryhas destroyed organic molecules... ...molecules based on carbon. or maybe there's no life on mars... ...and all viking foundwas a funny soil chemistry. or maybe there's life, okay... ...but it's not based on organicchemistry as much as life is on earth. personally, i don't think that'sa very likely possibility.
i'm a carbon chauvinist.i freely admit it. carbon is tremendously abundantin the cosmos... ...and it makes marvelously complexorganic molecules... ...that are terrificallygood for life. i'm also a water chauvinist. it's an ideal solventfor organic molecules... ...and it stays liquid overa very wide range of temperatures. but sometimes i wonder,could my fondness... ...for these materials haveanything to do with the fact...
...that i'm chiefly made up of them? are we carbon and water-based becausethese materials were abundant... ...on the earth at the timeof the origin of life? might life elsewhere be basedon different stuff? (liquid gurgles) i'm a collection of organic moleculescalled carl sagan. you're a collection of almostidentical molecules... ...with a different collective label.but is that all? is there nothing in herebut molecules?
some people find that ideasomehow demeaning to human dignity. but for myself, i find itelevating and exhilarating... ...to discover that welive in a universe... ...which permits the evolutionof molecular machines... ...as intricate and subtle as we. the essence of life is not the atomsand small molecules that go into us... ...as the way, the ordering... ...the way those moleculesare put together. now, we sometimes read...
...that the chemicals which make upa human body are worth... ...on the open market, only 97 centsor $10, or some number like that. and it's depressing to findour bodies valued at so little. but these estimates are for humans... ...reduced to our simplestpossible components. what is all this stuff in front of me? these are exactly the atomsthat make up the human body... ...and in the right proportions too. we're made mostly of water,and that costs almost nothing.
the carbon is counted as coal. the calcium in our bones is chalk. the nitrogen in our proteinsis liquid air. the iron in our bloodis rusty nails. some phosphorusand some trace elements. if we didn't know better... ...we might be temptedto take all these items... ...and mix them togetherin a container like this. and stir.
we could stir all we want... ...and at the end, all we'd haveis some boring mixture of atoms. how could we expect anything else? the beauty of a living thingis not the atoms that go into it... ...but the way those atomsare put together: information distilled over 4 billionyears of biological evolution. incidentally, all the organismson the earth are made... ...essentially of that stuff. an eyedropper full of that liquid...
...could be used to makea caterpillar or a petunia... ...if only we knew how to putthe components together. all life on earth is made fromthe same mixture of the same atoms. on another planet, the jars of life... ...might be filled with verydifferent atoms and small molecules. but i think the life forms on manyworlds will consist, by and large... ...of the same atomsthat are popular here... ...maybe even the same big molecules. so i don't believe we can rescuethe idea of life on mars...
...by appealing to someexotic chemistry. sometimes we hear aboutpossible life forms... ...in which silicon replaces carbon... ...or perhaps, liquid ammoniareplaces liquid water. but at martian temperatures,there are no... ...plausible silicon-based moleculeswhich might carry a genetic code. and ammonia is liquidonly under higher pressures... ...and lower temperatures. someday in the distant futurewe might have a collection of jars...
...each containing the elementarybiochemistry of another world. i don't know if there'll beone labeled "mars." but if there is... ...i bet it will befull of organic molecules. there's another way to searchfor life on mars... ...to seek out the discoveriesand delights... ...which that heterogeneousenvironment promises us. one of the things that a grasshoppercan do but viking can't... ...is move.
we landed in the dull places on mars. for all the solid, scientific findingsand hints which viking provided... ...we know that there are many placeson the planet far more interesting. what we need is a roving vehicle... ...with advanced experiments inbiology and organic chemistry... ...able to land in the safebut dull places... ...and wanderto the interesting places. this roving vehicle... ...was developed by therensselaer polytechnic institute.
it has a long list of dumb thingsit knows not to do. a mars rover hasn't got time to askif it should attempt a steep slope. radio waves travelingat the speed of light... ...take 20 minutesfor the roundtrip to earth. by the time it got an answer,it might be... ...a heap of twisted metalat the bottom of a canyon. a rover has to think for itself. imagine a rover with laser eyeslike this one... ...but packed with sophisticatedbiological and chemical instruments...
...sampler arms, microscopesand television cameras... ...wandering overthe martian landscape. it could drive to its ownhorizon every day. a distant feature it barelyresolves at sunrise... ...it can be sniffing and tastingby nightfall. billions of people could watchthe unfolding adventure... ...on their tv sets as the roverexplores the ancient river bottoms... ...or cautiously approaches... ...the enigmatic pyramids of elysium.
a new age of discoverywould have begun. most of the human specieswould witness... ...the exploration of another world. only 80 years ago, we could comeno closer to mars... ...than straining to seea tiny, shimmering image... ...through a telescope in arizona. now our instruments have actuallytouched down on the planet. viking is a legacy of h.g. wells... ...percival lowell, robert goddard.
science is a collaborative enterprisespanning the generations. when it permits us to see the far sideof some new horizon... ...we remember thosewho prepared the way... ...seeing for them also. on each lander, there is a microdoton which is written very small... ...the names of 10,000men and women... ...responsible for viking'ssplendid achievement. one of the names on this microdotbelonged to a friend of mine: a remarkable microbiologistnamed wolf vishniac.
he was the first personto build a machine... ...to look for microbeson another world. his friends called it the "wolf trap." it contained a liquid nutrient... ...to which martian soilwould be added... ...and any microbesthat liked the food... ...would grow in that nutrientmedium and cloud it. the wolf trap was selectedto go with viking to mars... ...but nasa is especially vulnerableto budget cuts...
...and it was removedas an economy measure. it was a terrible blow to vishniac.he'd worked 12 years on it. others might havestalked off the project... ...but vishniac was a gentleand dedicated man. he decided instead to study the mostmars-like environment on this planet: the dry valleys of antarctica,which were long thought to be lifeless. but vishniac believed that if hecould find microbes growing... ...in these arid polar wastes... ...the chances of life on marswould improve.
so in november 1973... ...vishniac was leftin a remote valley... ...in the asgard mountainsof antarctica. he set up hundreds of littlesample collectors... ...simple versions of the vikingmicrobiology experiments. on december 10th... ...he left campto retrieve some samples... ...and never returned. he had wanderedto an unexplored area...
...apparently slipped on the ice... ...and fell more than 100 meters. maybe something had caught his eye... ...a likely habitat for microbes... ...or a patch of greenwhere none should be. the last entry in his notebook was: "station 202 retrieved.2230 hours. soil temperature, minus 10 degrees. air temperature, minus 16 degrees."
it had been a typicalsummer temperature... ...for mars. some of his soil sampleswere later returned... ...and his colleagues discovered... ...that there is lifein the dry valleys of antarctica... ...that life is even more tenaciousthan we had imagined. that fact may turn out to be importantfor the future history of mars. there will be a time... ...when mars is thoroughly explored.
what then?what should we do with mars? if there is life on mars, then ibelieve we should do nothing... ...to disturb that life. mars, then, belongs to the martians,even if they are microbes. but suppose that mars isin fact lifeless. might we in some sense be ableto live there... ...to somehow make marshabitable like the earth... ...to terraform another world? as lovely a world as mars is...
...it poses certain problems. there's too little oxygen,no liquid water... ...and too much ultraviolet light. but all that could be solvedif we could make more air. with higher atmospheric pressures,liquid water would become possible. with more oxygen we couldbreathe the atmosphere. and ozone could formto shield the surface... ...from the solar ultraviolet light. the evidence for liquid watersuggests...
...that mars once hada denser atmosphere... ...which can't have allescaped to space. it has to be on the planet somewhere. in subsurface ice, surely... ...but most accessiblyin the present polar caps. to vaporize the icecaps,we must heat them... ...preferably by covering them withsomething dark to absorb more sunlight. that thing ought to also be cheapand able to make copies of itself. well, there are such things.we call them plants.
we would need to evolve by artificialselection and genetic engineering... ...dark plants able to survivethe severe martian environment. such plants could be seeded... ...on the vast expanseof the martian polar icecaps... ...taking root, spreading,giving off oxygen... ...darkening the surface,melting the ice... ...and releasingthe ancient martian atmosphere... ...from its long captivity. we might even imagine a kind ofmartian johnny appleseed...
...robot or human... ...roaming the frozen polar wastesin an endeavor which benefits... ...only the generations to come. it might take hundredsor thousands of years. we might, then, want to carrythe liberated water... ...from the melting polar icecaps... ...to the warmer equatorial regions. and there's a way to do it: we would build canals.
but that's exactly whatpercival lowell believed... ...was happening on mars in his time. the idea of a canal networkbuilt by martians... ...may turn out to bea kind of premonition... ...because, if the planetever is terraformed... ...it will be done by human beings... ...whose permanent residenceand planetary affiliation... ...is mars. the martians will be us.
mars today is strictly relevant tothe global environment of the earth. its antiseptic surface isa cautionary tale of what happens... ...if you don't have an ozone layer. its great dust storms and the resultingcooling of its surface... ...played a role in the discoveryof nuclear winter... ...the catastrophic climate change onearth predicted to follow nuclear war. so if you didn't have an ounceof adventuresome spirit in you... ...it would still make senseto support the exploration of mars. in recent years, there's been...
...a groundswell of interest... ...in organizing the first expeditionof humans to go to the planet mars. we first need more robotic missions,including rovers... ...balloons and return-sample missions... ...and more experiencein long duration space flight. but eventually, if all goes well... ...the interplanetaryship or ships... ...would be constructedin earth orbit... ...launched on the longjourney to mars...
...and then a landing modulewould set down on the surface. the crew would emerge... ...making the first human footfallson another planet. it would be very expensive,of course... ...although cheaperif many nations share the cost. the key issue in my mind is whetherthe unmet needs here on earth... ...should take priority. but that's a question even moreappropriately addressed... ...to the military budgets...
...now $1 trillion a year worldwide. you can buy a lot for that. justifications for the mars endeavorhave been offered in terms of... ...scientific exploration... ...developing technology,international cooperation... ...education, the environment. some see it as the obvious responseto the future calling. some even think we should goto investigate enigmatic landforms... ...including one that resemblesan enormous human face.
personally, i think this,like hundreds of other... ...blocky mesas there... ...is sculpted bythe high-speed winds. but if we're going anyway,there's no harm in taking a look. a remarkably diverse groupof american leaders... ...has endorsed the mars goal. i imagine the emissaries from earth... ...citizens of many nations... ...wandering down an ancientriver valley on mars...
...trying to understandhow a quite earth-like world... ...was convertedinto a permanent ice age... ...and looking for signs ofancient life along the river banks. in the long run... ...the significance of such a missionis nothing less... ...than the conversion of humanityinto a multiplanet species.
read also Bilder Schwörer Haus
