THEY USED TO fly airships here. Hence the outlandish aircraft hangers. Great cement rhomboids with curved corners, fashioned to conceal giant, weightless, long gone dirigibles from the eyes of equally obsolete enemies. Their startling outlines dominate Moffett Field. The former military base has been home to the Ames Research Centre since the US Navy thought better of the Zeppelin business and headed back to the coast. That was in 1939; something must have tipped them off.
  While the surrounding area of northern California is now famous as Silicon Valley, Ames deals in hi-tech of an entirely different order. It is an outpost in the empire of NASA. You wouldn't guess as much. If not for the military security at the gate, Moffet Field could be mistaken for a college campus out of term-time. Plain, rectangular office blocks don't so much sprawl as ramble halfway to the horizon, past soccer pitches, tree-lined pathways and parking lots. It is bland, calm, agreeable. Ordinary. Except for the hangers. Those could be flat-topped Toltec pyramids, or the barracks of an alien army as depicted on a paperback science-fiction cover. Antiquated, or futuristic? It's impossible to say. The same is true of what goes on here. Heading for the cafeteria, I pass a roped-off square of tarmac, on which a dozen togged-up couples swoop and glide away their lunch break to big band sounds issuing tinnily from a jury-rigged speaker. Nobody passing by looks very much surprised. Stranger things happen during working hours.
  At Ames, you will find scientists testing the limits of life. Scientists plotting the habitation of Mars. Scientists working out how to play pool with the universe. Scientists prospecting for Earth-like planets circling faraway suns. Ames is the hub of a new science, officially in existence for only three years: astrobiology.
  Astrobiology is NASA's new Big Idea. Its first all-out, whopping, cosmic, hearts-and-minds initiative since the moon landings wound down with the agency bribing America's TV networks to broadcast the Apollo 17 mission. After three decades of unmanned exploration and astronaut shenanigans in low-earth orbit; of shrivelling budgets; of public interest first wavering then waning; NASA has turned its attention to three core questions: “Where did life come from? What is its future? Are we alone in the universe?” Anything more heavy-duty than that and you would, literally, be knocking on heaven's door for your answers.
  In its simplest and shortest definition, astrobiology may be summed up as, “The study of life in the universe.” There's just one problem when it comes to studying life in the universe. So far, we're it. But as the director of Ames, an expatriated Scot named Harry McDonald, tells me, over the clatter and hubbub of the staff canteen: “We are really hoping - expecting - that as part of this work, we will come across life. Other life.”


IT'S official. NASA is looking for aliens. Cigar-shaped objects and pear-shaped conspiracy theories aside, other life has up to now been rather backward in coming forward. The rigorously monitored radio astronomy program conducted by the SETI Institute (as seen in the Jodie Foster movie, Contact) has yet to turn up a positive signal.
  SETI stands for the Search for Extra-Terrestrial Intelligence. The independently funded institute has a broad remit and even works in tandem with NASA; for example, it pays the wages of certain Ames scientists. But when it comes to the specific task of scanning the skies for bulbous-domed, almond-eyed stickmen, SETI is on its own. The United States Congress has expressly closed the public purse to this enterprise. NASA must not be involved. For astrobiologists, out of necessity, the quest for life beyond our planet begins with our “one data point”: home.
  I've come here to meet some of the scientists who, only three years ago, had no idea they were astrobiologists. There are, of course, astronomers at Ames, and biologists, but also physicists, geologists and chemists. All of these fields and many more combine to make up the splendidly rococo new multi-discipline that is astrobiology.
  Lynn Rothschild, an exuberant, evangelical 44-year-old who formerly took the title of protozoologist, now describes herself as a “poster person for astrobiology”. With her colleague and husband Rocco Mancinelli - six years her senior, and as measured and low-key as she is effervescent - Rothschild specialises in the study of extremophiles; life forms which thrive in extreme environments. In a slogan which one suspects is more Rothschild's than Mancinelli's, they proclaim: “Normal is passé; extreme is chic.”
  A block or two over, Kevin Zahnle, 46, impish, erudite, idiosyncratic, researches the evolution of the Earth's atmosphere. Chris McKay, 47 - a forthright, rugged individual who wouldn't look out of place manhandling rock samples in the world's wilder places, but today is ensconced behind his own desk a few doors down the corridor - is Ames's resident expert on terraforming; shaping the climate, surface and atmosphere of planets to make them habitable for Earth life. Across the hall from him works the head of the projected Terrestrial Planet Finder deep space mission, who's out at the moment - looking for terrestrial planets, presumably.
  When I meet Lynn Rothschild, she is just back from a field trip to California's Yellowstone park, unpacking evil-smelling samples which resemble little vials of seaweed soup festooned with dubious croutons. “When I was eight years old,” she explains, “I started raising protozoa in my bedroom. I'm not convinced my mother was all that thrilled with it. By the time I went to college, I knew I wanted to study slime and grime.”
  Often as not, Rothschild is to be found wading through hot springs in Yellowstone, snatching up samples of algae which can survive in battery acid, or bacteria untroubled by boiling water. These are then brought back to the duo's laboratory at Ames, where they share shelf space with microbes resistant to 3,000 times the fatal level of radiation in humans, and minuscule bugs called tardigrades which can be revived from a desiccated state of suspended animation after decades, even centuries. “They're not sexually active after 150 years,” Rothschild stresses. “But then I wouldn't be either.”
  These, and other organisms found further afield - in the arid valleys of Antarctica; near blistering volcanic vents on the ocean floor; far beneath the polar ice caps - are being tested in Rothschild and Mancinelli's lab. “Tortured,” as Rothschild cheerfully puts it, to see just how extreme they are. How low or high a pH level they can endure; how much and how little atmospheric pressure. How hot, how cold, how dry they can stand it. Their very existence, and their survival in these experiments, implies that life may not depend on the benign circumstances to which, on Earth, it has become accustomed.
  Says Rothschild: “Comparative biology suggests that the last common ancestor of all living organisms [on Earth] today may have lived at high temperature.” This in turn could indicate that life has developed on planets quite unlike the Earth. That there could be any number of scorching or freezing or acrid or brackish worlds out there, teeming with life.
  But what kind of life? Will it be simple, complex or intelligent? (Earth has produced all three, in that order, and sometimes appears to be heading back where it started.) Will it, like us, be carbon-based? Possess DNA? Fuel itself with oxygen? If not, by what chemical processes might it subsist, metabolize, reproduce?
  One hypothesis, much debated in the scientific community, was set out last year by geologist Peter Ward and astronomer Donald Brownlee. In their book “Rare Earth”, they posit that life in the universe is widespread but almost invariably microbial. Whatever's out there is liable to gift us not with advanced technology, but with dysentery. Some people - perhaps those who have spent too much time reading less scholarly works such as Michael Crichton's classic sci-fi novel, The Andromeda Strain - seriously fear the prospect that scientists will import alien diseases. There are even, Rocco Mancinelli informs me, in the same dispassionate manner with which he apparently greets anything from a routine memo to a fire on his desk, “Websites that are against bringing samples back from Mars. In case we bring anything back that's so dangerous it'll destroy the entire world.”
  “We go to extreme environments,” Rothschild emphasises, “precisely because they keep out what other people call advanced life. I don't consider it advanced, just multicellular. But there's nothing magic about multicellular life, there's nothing magic about being an animal that precludes it going from planet to planet.”
  She doesn't mean Russian dogs in space. One of the many ideas under investigation at Ames is panspermia: life travelling across the cosmos. Mancinelli, whose subject this is, highlights in his quiet way that, “This is not the classical panspermia as originally defined in the latter part of the 1800s. Lifelike entities which floated around through interplanetary space, and then landed on a planet that had the right kind of environment, and evolved and flourished. That's a bit nebulous, a bit mystical. But the concept of an organism that arose on one planet and then survived space travel to another, well, I think a lot of them could survive that.”
  Travel how? Most probably, by asteroid. A chunk of debris thrown off one planet by a collision with a meteor or comet could land on another, taking life with it. “We're not talking,” says Rothschild, “about little green men sitting in a boardroom saying, ‘We're going to seed planet X.’ We're talking about something where a chip of their home got knocked off.” To demonstrate that not only microbial but animal life could make this journey, Rothschild and Mancinelli plan to “fly” tardigrades; send them into orbit on the next available shuttle, to see how they cope with a zero-gravity space environment. But how plausible is the scenario they are seeking to test?
  “Likely or unlikely is a funny thing,” replies Rothschild. “In biology, all it has to do is happen once. All you need is one example, and that helps blast that ‘Rare Earth’ thing. I just want that one lousy tardigrade to survive up there for a couple of weeks. I think it makes a point.”
  And one point it could make is this: life on Earth might plausibly have arrived from somewhere else, most probably Mars. During the first half billion years of its existence, Mars may well have been a more hospitable venue for life than our own planet. Mars also has a relatively low escape velocity, making it easier for debris to leave its atmosphere. We know that chunks of it have landed on the Earth. Is it possible, then, that we are all actually Martians?
  That depends on what you make of ALH84001.


FROM the Rock of Ages to the fictional monolith of 2001: A Space Odyssey, taking in such eminent stones as Rosetta, Blarney and Scone along the way, there has never been an igneous lump so celebrated or reviled as ALH84001, aka “The Mars Meteorite”. Its acclaim was to prove brief; in fact, meteoric.
  On August 7th 1996, after a long and detailed examination of this Martian fragment found in the Antarctic, a NASA team announced that its “tubular structures. . . represent fossilized nanobacteria.” Headlines of a sort usually confined to the most lurid and seedy tabloids broke out like a rash across the front pages of Britain's broadsheets. It was top of the news on every TV bulletin. Yes, there was life on Mars. This should have been the day the Earth stood still. A moment of awestruck silence brought on by the certain knowledge that we were not alone in universe.
  As it happened, little could be heard over the immediate and forceful clamour of other scientists insisting that the tubular structures were not proven to represent any such thing. The cavities might just as easily be of chemical

origin, or simply caused by weathering. The story plummeted from the public gaze like, well, a stone.
  Among scientists, the matter is far from settled. A fierce debate still rages over whether the teeny-tiny holes in ALH84001 were made by life, or merely the elements. “It has,” sighs Rocco Mancinelli. “split the community in two. It's polarised. People have attacked each other, and attacked each other so viciously. At meetings of the two opposing groups, it gets vitriolic. I'm not sure they're even listening to each other any more.” Mancinelli is not a man given to overstatement. One imagines these meetings almost as pitched battles fought with clipboard, pointers and clods of interplanetary flotsam.
  But, evidence of alien life or not, the effect of the meteorite was hugely important for astrobiology, then lurking in rudimentary form under the considerably less poetic moniker of “exobiology”. Suddenly, people were interested in space again. More than interested. Enthralled. It's not too fanciful to say that, as far as the USA was concerned, AHL84001 was astrobiology's Sputnik - an event which startled a nation and left it highly receptive to science's response. True, speaking both literally and metaphorically, Sputnik actually flew. All the same, NASA's canny boss, Daniel Goldin, was not about to miss an opportunity like this. As Chris McKay puts it: “Dan Goldin saw a good thing. He basically said, ‘Hang on, let me get in front of this, 'cause I'm the leader.’”
  Hung on Chris McKay's office wall, a framed poster from Disney's Fantasia depicts Mickey Mouse, in conical hat and wizard's sleeves, conjuring forth stars and comets. Nearby, a record shop calender bears the slogan, “No Music, No Life.” Pasted over “Music” is the word “Water'. On the bookshelf sits a bag of lapel pins reading, “Mars Or Bust.”
  What is it about Mars? NASA first landed on the red planet in 1976. The unmanned mission was named Viking, and its slogan might as well have been “Mars And Bust.” For a few people, like McKay himself, Viking was an inspiration. He was a 22-year-old post-graduate physicist. “It was one of those random events that shaped my future career. That's the first time I got interested in the question of life, particularly on Mars.”
  For most, though, Viking was a grave disappointment. Technically, the project was a remarkable success. The probes made it safely to the surface, and their automated laboratories sent back plenty of data. Trouble was, none of it so much as hinted at any signs of life on the planet. Such was the level of expectation ahead of the venture, there persisted an irrational, almost religious conviction in some quarters that “other life” would hang out the streamers, dish up the sausage rolls and crack open the Babycham for the Mars lander. Viking - a brilliant achievement - was seen as a failure. The very notion of searching for “other life” became somewhat disreputable in scientific circles, a furtive pursuit for kooks and zealots and people who'd eaten too much pizza before bedtime. Only now, largely thanks to ALH84001, has it high-kicked its way out of NASA's closet.
  Some might trace our obsession with Mars to “The War Of The Worlds” by HG Wells. But Wells never claimed his writing to be anything other than fiction - unlike his contemporary, the astronomer Percival Lowell. One of the most highly regarded scientists of his day, Lowell authored such works as the 1908 tome, “Mars As The Abode Of Life.” He created, with no scientific basis whatsoever, an entire mythology of an intelligent race on Mars. Such was his reputation that the notion became embedded in the public consciousness as fact. It is a problem that NASA has to contend with to this day.
  When I ask Kevin Zahnle about Mars, he slams a Lowell biography down on his desk in front of me. A pause for effect. Then, “Percival Lowell, Percival Lowell, Percival Lowell,” he repeats, in a tone of exasperated affection. “Our field has suffered badly and gained greatly because of Lowell. He's inextricable. Lowell's influence continues to misrepresent to the public what Mars is. Mars is, in all likelihood, a dead planet. It is cold. It is dry. It is not a pleasant place to live. But it's the only other planet you can imagine living on. You don't really have anything else to fantasise about. So you pick Mars.”
  Yet everyone I've met at Ames seems just as engrossed with the place as any sci-fi freak or flying saucer spotter. Chris McKay is convinced that a manned mission to Mars is only a matter of time.
  “One of the key goals of astrobiology,” he says, “is to find a second genesis. Of all the planets in the solar system, even the moons, Mars is the most likely candidate. And the only way to find out it is to go look.”
  And when we do go, it seems, we're going to fix the place up.


TERRAFORMING - customising a planet to suit Earth life - is central to astrobiology. When you pose the question, “What is the future of life in the universe,” it makes sense to consider that the answer could be, “Us.” Even if extra-terrestrials don't come to call - and they don't seem to be in any hurry - we may end up as extra terrestrials ourselves. That means we'll need somewhere to live. Somewhere like home - or as similar as we can make it.
  Chris McKay leans back in his chair and breaks the bad news. His authoritative Florida baritone gives his voice a kind of airline pilot quality. You instinctively take him seriously.
  “Ultimately,” he says, “we have to leave the Earth. Maybe as soon as half a billion years. At the very longest, in five billion years, when the sun goes red giant, the Earth is toast.”
  When the scientists at Ames think of terraforming, their thoughts invariably turn to Mars. But if the jig's up for the Earth, won't the same go for Mars?
  “Mars is not a solution to our long term problems,” agrees McKay. “It's the near-term step that'll be the first; the baby steps. And right now Mars is the only step. There's no choices. We either take that step to Mars or we wait a long time, and maybe something else turns up. And that's like Columbus saying, ‘Well, I'm not going to sail to the New World, I'm going to wait till they invent seven-forty-sevens and then I'll fly to the New World.’”
  As for exactly how one goes about renovating a planet, Kevin Zahnle relates the details with relish. Zahnle, although raised near Chicago of German farming stock, is a very Californian kind of nonconformist: “Pro-Gore, pro-environment, pro-nuke.” He revels in the notion of planetary DIY: “There are so many things that you could do to improve Mars. I mean, just look at my own yard. There's always things I can do to improve it. You'll start looking that way at your solar system. You splatter a few very large comets across the surface of Mars,” he says gleefully. “You'd do the same thing eventually to Venus. Drop something the size of Pluto on it.” He reconsiders, relents. “Maybe half the size of Pluto will do it. But that,” he cautions, “will take more active work. You can't really let it get warm, it'll get rid of its water and become uninhabitable again. You need to keep an eye on it.” I find myself nodding dutifully, as if to affirm that I will, indeed, keep an eye on Venus or suffer the consequences.
  If, by the way, you find this far-fetched, bear in mind that NASA have already announced plans to commemorate American Independence Day, 2005 with something a little grander than the customary Fourth of July fireworks. They're going to - very visibly - blow up a comet. Scott Hubbard, formerly the deputy director at Ames, has predicted that terraforming will be under way by 2050.
  “That's pretty. . . optimistic,” muses McKay. “But terraforming is physically possible. And there are some immediate returns. Human-caused climate change on Earth necessitates human-caused remedies. Creating a biosphere on Mars could be a very important learning experience for maintaining a biosphere on Earth. We humans will need to assume management responsibility for the biosphere whether we like it or not. The Gaia theory is, you leave it all alone and it'll take care of itself. But it just ain't so. We have to take control and make sure it works right, or,” he frowns, “it's grim bananas for us.”
  So astrobiology may yet save the world. And, having done so, save us for entirely new worlds. While the Creationists and the Greens are trying to knit an escape craft from hemp and old Bibles, those of us who trusted in science could be blasting off to a customised planet a thousand generations west of Andromeda.
  It's an ambitious vision for an ambitious science. There are those who would dispute it. Moreover, there are many who would dispute the value of astrobiology in the first place.


ALONG with fellow space program veteran Bruce Murray, and the late and revered popular astronomer Carl Sagan, Louis Friedman founded The Planetary Society and serves as its executive director. This international organization, now 100,000 members strong, promotes space exploration and the search for extra-terrestrial intelligence. Friedman's opinions carry weight, so it is telling that he chose to describe astrobiology as, “A subject without subject matter.”
  But that was three years ago. Since then, astrobiology has shot forward along the path to scientific credibility, sped along by that most reliable of lubricants, money. “There's nothing like the prospect of funding,” says Chris McKay, “to make academics and researchers take a topic seriously. People's ears perk up: ‘Yeah, I've been interested in that for some time.’”
  Astrobiology is not without its critics. Writing in the scientific journal Nature, Jack Cohen and Ian Stewart of the University of Warwick's Mathematics Institute, assert that the subject has far too narrow a focus. “The trouble with astrobiologists,” Cohen tells me, “is that they're really looking for more astrobiologists.” In other words, astrobiology only seeks life as we know it: carbon-based, and fuelled by oxygen. “A balloon like creature floating in the atmosphere of Jupiter,” write Cohen and Stewart, “would probably regard the terrestrial environment as lethally unattractive.” Or, as Nature's senior editor, Henry Gee, observes, “When the Mars Rover sat and stared at a rock, how do we know that the rock was not staring right back?”
  McKay has a simple answer: “We don't. But on the other hand,” he points out, “we don't know enough to even look for life like that. A practical strategy is to first look for life in environments that we're familiar with, and look for life that's somewhat like us. I wouldn't be optimistic that we would be able to develop a reasonable strategy for searching for life that's truly alien. What do we do, go to Mars and shake every rock - “Hello? Hello?’”
  Science fiction writer Brian W Aldiss has offered an opposing but equally sceptical commentary on astrobiology, calling it “the latest manifestation of this creaking floorboard in the brain. . . an apparently insatiable craving for the exotic.” There is, he asserts, no “other life” to look for. Aliens are merely the Things That Go Bump In The Night of a modern mankind no less superstitious than its ancestors.”
  For a quarter of a century, scientific orthodoxy has followed the approach of French biologist and 1965 Nobel Laureate Jacques Monod: “Man at last knows that he is alone in the unfeeling immensity of the universe, out of which he has emerged only by chance.” Now it's up to the likes of Lynn Rothschild, Rocco Mancinelli, Kevin Zahnle and Chris McKay to prove the orthodoxy wrong. “The underlying assumption of astrobiology,” McKay declares, “is what you could call the Copernican principle: that the story which happened here on Earth is not a freak. Not a fluke. It's typical. And it's likely to have happened elsewhere.
  “I think that many years down the road historians of science will look back and see that there was a sea change in our view of life at about this time. And right now,” he says, with a rare grin, “being at Ames and being part of astrobiology program is like being sprinkled with holy water.”
  Blessed are the astrobiologists? If so, they stand to inherit much more than just the Earth.

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