The Rock From Mars (24 page)

“Absolutely,” Schopf said. “And I’d like to see data on a couple thousand individuals. . . . You say, oh, that sounds like a lot. In the Apex chert, the oldest fossils on this planet, I have personally measured nineteen hundred, nineteen hundred and fifty cells. That is what is required to nail this thing.

“Okay, give me five hundred. That’s enough. That’s enough.” The audience was laughing now.

When Goldin declared the press conference over, reporters surged toward the scientists at the front of the room to press for still more information.

By the end of it, the sleep-deprived Zare felt a growing desire to escape from what he considered the “surreal grandiosity of the moment,” the relentless, burning attention of the TV lights and staring reporters.

Instead, as the day wound down, he scrambled to his hotel to finish an opinion piece he had been working on for
The
New York Times,
an article that was suddenly in urgent demand. Then he was hustled off to a public television studio across the river in the Virginia suburbs, to tape an interview with PBS’s Jim Lehrer for that evening’s news. Zare had expected to be paired with McKay for that appearance, but NASA decreed that Huntress should do this one instead.

When Lehrer asked Zare why all this should matter to the rest of us, the scientist responded that he thought everyone must be a little curious about the fundamental nature of life, how it starts, how rare it is, and the possibility that biological material, on occasion, might have traveled from Mars to Earth on a meteorite and might even have provided the first seeds of the living world billions of years ago. Zare posed the question: “Is it possible that actually we’re all Martians?”

None of them was prepared for the magnitude of the public response.

By early on August 7, the day of the press conference,
Science
magazine and the AAAS had posted the McKay paper on two Web sites (its fledgling EurekAlert and the online version of the magazine). Within days, almost a million people had seen the paper by that means.

NASA’s Web site scored more than half a million hits the first day. By the end of that week, the NASA public affairs staff had counted more than a thousand stories about the rock broadcast in the top thirty-nine U.S. TV markets alone, in addition to vast coverage in newspapers and magazines. The story eclipsed former space news events such as the first landing on the moon, the first flight of a space shuttle, and the explosion of the shuttle
Challenger,
the staff reported.

“
Des Traces de Vie sur Mars,
” trumpeted the French newspaper
Le Figaro.
“In many ways . . . the headline mankind has been waiting for since the first human eyes looked into the heavens and saw God, fear or some amazing future journey,” said a cover story in
USA Today
about the potential implications of the news.

Despite the unmannerly way in which the story hatched out of its protective shell, the predominant opinion among a sampling of scientific and journalistic evaluators was that the bulk of the initial reports were balanced and accurate—though inevitably lacking the amount of detail many scientists would always prefer. A few outlets were deemed guilty of some degree of exaggeration, most often an overstatement of the degree of certainty that Mars had once had microbes. And there were isolated irritants, such as that fleeting invocation of maggots, which so upset Zare and others. Regardless of the content of the reporting, Schopf, for one, suspected that the sheer volume of headlines and other coverage created the false public impression that the McKay team had already made a persuasive case for primitive life on Mars.

Congress scheduled hearings on the rock, with testimony from scientists and policy makers. The Clinton administration scheduled a “space summit,” to discuss the appropriate government follow-up. An auction house in New York ran an ad in
The
New York Times
proclaiming that the twelve known “meteorites from Mars have been thrust into the position of being perhaps the most precious natural objects in the world.” It offered for sale the only collection of SNC fragments in private hands.

The iconic seventy-five-year-old Ray Bradbury, author of
The Martian Chronicles
and other science-fiction classics, gave the rock a curmudgeonly nose thumbing. He refused Ted Koppel’s invitation to appear on
Nightline
to talk about it, because he didn’t believe the claims and “didn’t want to be a grouch.”

Microsoft’s chief strategic daydreamer, group vice president Nathan Myhrvold, wrote an essay, which
Time
magazine excerpted from
Slate
online, cheerfully calling the McKay group’s announcement “the biggest insult to the human species in almost 500 years.” In the short span of human existence, the revelations of science had managed to demote the home planet from the center of the universe, where Ptolemy had put it in the second century, to insignificance somewhere in a cosmic outback. And now it seemed the planet was losing its status as the lone oasis of life. But, Myhrvold and others suggested, location is not always everything. Humans still had the only known
intellects
in all creation, didn’t they?

Back at Building 31 in Houston, the contemplative calm was shattered. Employees arriving for work might find as many as twenty news crews lined up in the lobby, waiting their turn to go into the meteorite lab. For days and even weeks, the inhabitants felt as if they had been invaded.

Everybody connected with the McKay team was inundated with phone calls, requests for interviews and autographs, and other kinds of attention. Collectively, over that fall and winter, the group would do some 260 TV, radio, print press, and lecture appearances around the world. In Australia alone, McKay would give five lectures in five cities in five days.

Gibson would do more traveling in the nine-month stretch following the press conference than he had in all his twenty-eight years at NASA combined. He appeared before the Royal Geographic Society in London, at the same podium where Stanley and Livingston and Amundsen had been welcomed.

Robbie Score, the rock’s discoverer, had quite recently left NASA and Houston behind to answer the lure of the Antarctic. Just as “her” rock was becoming world famous, she had taken a job that would enable her to spend the austral summers back in the forbidding, enchanting place where she had found it. Still, with the help of the National Science Foundation, the media troops tracked her down. In numerous newspaper and magazine articles she became the face of the Antarctic meteorite search teams.

Chris Romanek, also off at a different job, would get sporadic calls from NASA officials trying to fill the public demand for speakers familiar with the story of the rock.

The rock also helped force the resignation of presidential adviser Dick Morris. In one of its odder ripple effects, the NASA press conference lent credibility to call girl Sherry Rowlands’s tales of presidential eavesdropping, convincing the
Star
reporter that she was worth paying $50,000 for her revelations. The tabloid splashed the story across its front page on August 29. Morris quit the same day.

The reaction that McKay and his team cared most about came, of course, from fellow scientists. The group knew they had dared to stake out a preliminary claim to one of the so-called holy grails of science. There would be only one chance in history to discover the first proof of life on another planet. If they were right, they would also displace Schopf, in the textbooks, for having found the oldest known life on any planet, including Earth. If they were right, their discovery would be as unsettling to existing models of reality as the Copernican revolution had been. And their names would be in the history books forever.

As Schopf had made plain, such a coveted trophy would not be retired without a fight. But no one on the McKay team had foreseen the ferocity of it. The response began like a temblor, a subtle rumble of something beginning deep down and building toward release at the surface.

Then it rose up in their faces like a screaming, scouring Martian dust storm.

CHAPTER TEN

SCHOPF SHOCK

W
HEN HE ARRIVED
at the Friendship Hotel in Beijing, Bill Schopf could tell at once that the type of limestone used to tile the registration desk and lobby floor had been constructed 850 million years ago by slimy microorganisms. The distinct curvilinear layers of light and dark that graced the decor were laid in cycles of long-ago life and death.

In the summer of 1982, fourteen years before the NASA press conference, Schopf and his wife were guests of the Chinese Academy of Sciences, doing research at the Institute of Botany. The forty-year-old visiting professor took a picture of that lobby, with his wife in the foreground for scale. He recognized the rock formations because he had just been working near the village of Jixian, east of Beijing, at a site where they occurred in nature.

The Chinese called them “flower ring rocks.” To geologists like Schopf, they were known as stromatolites (pronounced stroh-MAT-oh-lites, a word derived from the Greek for “stony carpet”). The Chinese had been using the material in their buildings for more than two thousand years. Schopf saw examples in the Forbidden City, at the Temple of Heaven, and in the columns of the Great Hall of the People on Tiananmen Square.

Just as the Chinese had constructed their edifices of flower ring rocks, Bill Schopf was building a career on them. Sometimes it seemed his entire world, everywhere he looked, was layered in the ancient husks of microscopic builders.

One day, Schopf and his wife arranged to visit a vast factory where Chinese workers cut and polished the rocks. Schopf noted the variety of colors and designs the microbes had devised—“light gray with jet-black layers, dark gray set off by beige or light gray layers, dull red to pink and purple flecked with whitish zones.”

Schopf’s hosts even gave him a bargain deal on a damaged but still spectacular slab of Precambrian stromatolites arrayed in columns of bright red crossed by veins of sparkling white calcite. The Schopfs later arranged to have the piece embedded in a place of honor in the entryway of their Los Angeles home, which was strewn throughout with assorted stromatolite paperweights and doorstops.

Over tea and cakes in the factory managers’ offices, Schopf tried to explain why he had become an aficionado of stromatolites in all their manifestations: he thought they might just be the mother lode of clues to the elusive history of Earth’s earliest living things. His hosts could not have known that Schopf’s quirky preoccupation with their construction material would help alter human perceptions of how they (humans) came to exist and, in the bargain, make him the “god of the Precambrian.”

Before the year was out, Schopf would have in hand the specimens from which flowed the discovery that would bring him international acclaim. This was the path that would lead Schopf to sit on that brightly lighted NASA headquarters stage with David McKay and the others on August 7, 1996.

The encounter would accelerate the interweaving of both knowledge and doubt from two fields that had been segregated: studies of the most ancient rockbound mysteries of life on Earth and the search for their counterparts on Mars. And it would touch off a bitter personal antagonism between the fiery academic and the reserved NASA civil servant.

Schopf approached his public comments about the meteorite with the gimlet eye of a man who, after all, had devoted his life to the daunting task of finding ancient signs of life entombed in rock. He knew this kind of work involved bad odds piled on top of evil odds—even on his own home planet, where he could pick his shots, and where there was no doubt that life abounded. But a single specimen from Mars, selected randomly in a primordial bombardment—?

Schopf knew what it took to beat back the critics in such cases. This was his turf. It was where he had spent his life, and it was a point of pride that he was among the few to acquire the unique blend of expertise the task required, in chemistry, microbiology, geology, paleontology, physics—the list went on.

In 1960, as an eighteen-year-old sophomore at Oberlin College in Ohio, Schopf had developed a keen interest in finding the missing record of Earth’s earliest life—even though it was a singular mystery whose resolution seemed frustratingly beyond reach.

Scientists had found a stunning diversity of multicellular life forms revealed in the remarkable fossil record of the “Cambrian explosion,” beginning about 550 million years ago. But if Darwin’s theory of evolution was correct, there ought to be some sign of the long buildup to this rich biological harvest. And yet, the first four billion years of the planet’s history remained, for the most part, a stubborn blank.

This mystery period—the Precambrian Eon—encompassed some 90 percent of Earth’s prehistory and almost a third of the age of the known universe. The sun and planets had condensed from a cloud of dust and gas, and the Earth formed out of the collisions of smaller bits of debris. Organic molecules appeared. At some point, the planet’s primordial chemical soup spawned what might be considered the mother cell of all known life. That entity diversified into the known domains—bacteria and their single-cell cousins on one branch (plus an entire branch, the Archaea, still undiscovered in 1960), and on another the more complex domain of animals, plants, and fungi.

Until the 1950s, pioneering souls who attempted to claim discoveries of Precambrian life signs met with either embarrassing reversal or skepticism and ridicule from influential and dogmatic scientists. Some people scoffed at the radical notion that anyone could find actual proof of bacteria in rock half a billion or more years old.

The skeptics had plenty of ammunition. On teeming Earth, all but a fraction of a percent of primitive living things got eaten or otherwise used by other living things. Very few biological scraps lingered long enough to be preserved (buried) as fossils. As for the rock that entombed this record, the planet recycled most of it. Most terrestrial rock had been heated to incandescence or altered by water or otherwise processed by nature in ways that wiped out any signature left by fragile life-forms of long ago. Geologists referred to this state with the useful acronym FUBAR (“fouled up beyond all recognition”).

In 1961, just as Schopf’s youthful interest in the subject was perking up, an expedition to a supersalty lagoon called Shark Bay, on Australia’s west coast, found the first compelling evidence that stromatolites were a product of living creatures. Exhibit A was a community of stromatolite colonies currently alive and thriving—and building layered rock that looked remarkably like formations known to be billions of years old. These constructions, in other words, had not evolved in all that time and, as researchers would later show, neither had the microscopic builders themselves.

The discovery of live colonies ended a long-simmering controversy that had hobbled progress on the mystery of Earth’s earliest life. Schopf was troubled by a phenomenon that had contributed significantly to the delay. That was the combative resistance of a smart, powerful, well-credentialed scientist, Sir Albert Charles Seward. “His aggressive skepticism, delivered from his throne of unquestioned authority, was a disservice to the field,” Schopf would write years later. “His dogmatic pronouncement . . . stifled the hunt for the missing Precambrian fossil record for nearly 40 years.”

Schopf himself, as he sat on stage with David McKay in 1996, would be in a similar position, that of powerful authority figure with the imprimatur of textbook wisdom. He, too, would be influential in hindering or accelerating the pursuit of an unconventional line of inquiry. Right or wrong, he knew, the stature of individuals affected the process. But Schopf, like Seward, had to rely on his ability to read the evidence put in front of him. The evidence—the data—was the final arbiter.

At least one mentor warned the young Schopf that his chosen line of inquiry, so tricky and contentious, could be a career dead end. But Schopf had grown up in a family of scientists, his mother educated in botany and math, his father a paleobotanist. He was loaded with outward self-confidence, he was comfortable with conflict, and he had, as he says, “the Precambrian fire in my belly.” He believed Darwin was right and thought he, Bill Schopf, had as good a chance as anyone of proving it.

In 1963, after graduating from Oberlin, Schopf entered Harvard University as a student of Elso Barghoorn, the noted paleobotanist—a specialist in plant fossils and geology—who had helped give birth to the new field Schopf now embraced. Barghoorn had helped identify milestone fossils, the first ever found from the mysterious Precambrian time. A colleague had discovered the fossils in the Gunflint Formation, a band of rock along the northern shore of Lake Superior in Ontario that was rich in a glassy black rock called chert (ideal for producing sparks and used as flints for early muzzle-loaders). The fossils were embedded in wave-washed outcroppings of the rock, stacked like hotcakes in concentric rings up to three feet across. Stromatolites!

The Gunflint discovery represented the first known microscopic fossils and, at 1.9 billion years old, the most ancient fossils of living things yet found.

In the course of his work with Barghoorn, the young Schopf found himself a co-conspirator in a demonstration of just how cutthroat even the most respected scientists can be when the stakes are high. As in the Seward case, Schopf was struck again by the realization that the pursuit of truth can never be isolated from the character of the individuals pursuing it.

For years, Barghoorn had been putting off logical follow-up work needed on the breakthrough Gunflint discovery. He had intended to interpret, describe, and name the early life-forms represented in the fossils. In the summer of 1964, another scientist abruptly preempted Barghoorn by submitting a manuscript to
Science
magazine that accomplished the follow-up Barghoorn had neglected to do. The editor at
Science,
as part of the routine peer-review process, sent a copy of the paper to Barghoorn for an honest, independent assessment of its validity. That was not what the editor got.

“Barghoorn was livid” when he saw the other man’s paper, Schopf would write years later. Barghoorn instructed his protégé, Schopf, to help him deliberately delay the rival paper for a couple of weeks, so that the two of them could use the time to get their own version of the work ready for publication.

This tactic led them to cut a significant corner. Because of their competitive rush, Barghoorn and Schopf did not take the time to examine the actual individual fossil specimens but, rather, relied on photographs for their analysis. “This, I am sorry to say, is not good science,” Schopf would write. “It’s true that we were forced into this by unusual circumstances, but this was not the proper way to do this job.”

Apparently through his stature and sheer audacity, Barghoorn persuaded both the author of the rival paper and the editor of
Science
that Barghoorn’s paper should be published first. And so it was.

Schopf acknowledged that, to an outsider, this kind of maneuvering over who got credit “must appear unseemly, even tawdry. And of course it is. But science is done by real people, and it’s much more competitive than one might expect.”

In the world of science,
credit
is prime currency.

Decades later, some of those feeling the sting of Schopf’s criticisms would point—fairly or not—to this incident, or more particularly his attitude toward it, as a sign of his take-no-prisoners approach in dealing with perceived rivals and threats to his status. (This was a perception that Schopf would vigorously challenge.)

Meanwhile, a gathering weight of evidence soon satisfied the wider world that Precambrian fossil hunters had indeed found an effective strategy for ferreting out the hidden record of Earth’s early biology. The strategy was this: the hunters would look for flower ring rocks—stromatolites—composed of cherty, coal-like rock (rich in organic carbon) with a fine-grained texture that showed it had not been subjected to the heat and pressure that rendered most fossils unrecognizable.

In 1982 (the same year as his tour of duty in China), Schopf’s travels took him to a site in the rough, dusty outback of northern Western Australia. His destination was one of the oldest rock formations known on the planet—and more flower ring rocks.

On this trip, he and coworkers took samples from a rock unit 3.465 billion years old, known as the Apex chert. The collection would make his reputation—but not without about a decade of tedious and sometimes contentious labor by him and his student assistants. The real hunt took place not in the outback but back in the laboratory, during long, meticulous microscope sessions. The features under study were charred, shredded, cooked, fragmented, and generally difficult to make out—hardly worth his attention, he noted, if they weren’t so ancient.

Two graduate students in succession studied the specimens and “found nothing.” A third, in 1986, detected something interesting but moved on to other work. (These difficulties—the degraded state of the samples and the fact that the grad students had seen nothing significant in them—in the year 2002 would take on importance.)

Schopf himself took another look at the Apex chert samples in 1989, while on detached duty in London.

He probed for three kinds of evidence to prove he was seeing tiny cellular Precambrian fossils: the presence of layered formations built by microscopic organisms; the organic matter produced in biological processes; and the fossilized cells themselves. He wanted cellular shapes that had been preserved in three dimensions instead of squashed like roadkill.

After several months, Schopf identified a total of eleven different types of microorganisms from the chert samples. He described three of them in an article published in
Science
magazine in 1992, and reported eight more in 1993. Schopf wrote that he could see clearly in these ancient forms the outlines of rounded cell walls and other shapes familiar in modern-day microbes.

His interpretation of the evidence upset the conventional thinking. In the last decades of the twentieth century, Schopf and others painted a stunning new picture of Earth’s evolutionary history. In this scenario, life began much earlier and evolved more rapidly than anyone had suspected.