THE FOUR-POUND ROCK CAME TO US free of charge, a gift from the heavens, hurtling through the atmosphere and plummeting to Earth without the aid of astronauts, space stations, or the National Aeronautics and Space Administration. Before that time it had existed placidly for more than four billion years as part of the surface of the planet Mars, oblivious as the climate shifted from balmy to harsh, as the water that once flowed freely mysteriously vanished, as meteorites bombarded the planet and fractured the ground. At some point, a signal event occurred: A particularly violent meteorite collision launched the rock into space, where it floated, ignored and unimpeded, for 16 million years. Then came another signal event: The rock succumbed to the inescapable pull of Earth’s gravity. Glowing from the heat of its descent, the rock formed a thin shell around its inner core, protecting its history within.
It landed in what is for meteorites the neighborhood of choice: Antarctica, the pristine, sterile, keep-to-yourself continent. There the rock lay for 13,000 quiet years. Having missed the era of dinosaurs, it now remained profoundly anonymous during the creation of cave paintings and the construction of the pyramids, during the rise and fall of the Roman Empire, the French Revolution, the two world wars, and Elvis. And then, with the crunching of snow boots on a jagged ice field in 1984, the rock had its first contact with humanity.
It was picked up on a routine meteorite-gathering expedition by a NASA scientist who was drawn to its luminous green cast, an attraction that owed everything to her green-tinted sun goggles. It was flown back to the agency’s Johnson Space Center in Houston, where it was wrongly identified as a diogenite—an asteroid fragment—and sequestered in a nitrogen-enhanced cabinet when it wasn’t being examined. No one except a few NASA planetary scientists (scholars who devote their lives to the study of planets) paid the rock much mind until 1993, when an old NASA hand who happened to be one of the world’s experts on diogenites found it troubling. He ran a few tests, scratched his head, and ran a few more. The rock was similar to a diogenite, but it wasn’t a diogenite. In fact, its chemical characteristics resembled those of only eleven other rocks on Earth, all of which, science had determined, came from the same place: Mars.
As word of the discovery spread, and as other scientists confirmed the finding—gases extracted from the rock were compatible with tests of the Martian atmosphere done by the Viking spacecraft in 1976—the rock’s eons of obscurity came to an abrupt end. Suddenly, everyone wanted a piece of the rock: scientists in London, scientists in California, scientists in the Johnson Space Center’s Building 31, where some of the country’s top planetary scientists work on the government payroll. Researchers would request a gram of it and be given a tenth of a gram because the rock had become precious and irreplaceable; normally voluble colleagues became unusually silent and secretive once they got their hands on it. For twenty or so years the search for life on Mars had essentially been abandoned because Viking had found no signs of life there. Now this rock’s chemical composition gave off enticing hints that Viking, which had analyzed only the planet’s soil, had missed something—or had not known where to look.
And so this rock was launched on another trajectory, one that would propel it from NASA’s labs to the White House, one that would have it serve the needs of everyone from NASA scientists and brass to presidential candidates, network news reporters, and even one very shrewd Washington, D.C., prostitute. Some people hoped the rock would be the biggest thing since Copernicus. Some people hoped it would unlock the secrets of the universe, that it would prove that we are not alone. It might, some people hoped, tell us who we are.
But maybe, in a strange way, it had already done that.
WE DID NOT GO LOOKING FOR LIFE—life found us,” David McKay would say in mid-September 1996, but that wasn’t exactly true. Almost from the moment he first heard of the rock at the Johnson Space Center ( JSC), he had known what its potential was, but as a scientist he was still hedging his bets. Now he was being heralded worldwide as the mild-mannered leader of the NASA team that had announced in August that they had possibly—the qualifier was most assuredly his—discovered life on Mars. He had testified before myriad government subcommittees, spoken with nearly every reporter on the planet, cooperated with a Discovery Channel documentary on his team’s research produced by Walter Cronkite, and begun to realize that he would not be deluged by the typhoon of scientific criticism he had anticipated. Even so, McKay wasn’t letting success go to his head.
He was sixty, white-haired, and bespectacled, a tall man with a hurried gait and the stooped posture of a dedicated microscopist. Before the Mars rock came into his life, caution and conservatism had allowed him to develop an admirable if not spectacular reputation in the field of planetary science; a Rice University graduate, he had been recruited during the glory days of the Apollo program to teach geology to the first astronauts headed to the moon. Since then McKay had written more than three hundred technical papers, received numerous professional honors, and reached the top of his division’s pay scale at the JSC; as of 1994 he was financially secure and happily married with three daughters, two of them grown. He was not, in short, the kind of man who would be tempted to risk throwing it all away. But then he heard about the Mars rock.
The reclassification from a diogenite to a Martian meteorite had made the rock the star of the 1994 Lunar and Planetary Science conference in Clear Lake. Its presence there was fortuitous. Though the desire to explore other planets was deep and abiding in the popular culture—by 1995, four