The Rock From Mars (35 page)

David McKay had envisioned the collaboration as a collegial, open one, in which information was shared and discussed, in marked contrast to the secrecy of the past. Now he felt angry and pained that some members of the team had taken such an aggressive stance against him—and that his own brother was securing their funding. It was also awkward for those with friends on both sides. For instance, a woman in David McKay’s laboratory was in a romantic relationship with a man on the Blue Team.

As the principal investigator on this project, Gordon McKay had gone into it with the idea that his group could simply contribute new information to the debate. He soon saw that some of his coworkers were more combative in their pursuit of the case against his brother’s claims. He realized they saw the setup as deeply adversarial and, for example, would decline to tell David McKay their results until they were ready to publish. This remained a sore subject in the building, where—in keeping with the tradition growing around the rock—players even within the same family could have differing interpretations of its meaning.

Gordon would later note that he had much less of an emotional investment in the answer than his brother, and therefore did not feel the pain over their differences that his brother clearly felt. Like many who had seen combat in the battle of the rock, Gordon was mainly tired of it.

The Blue Team contingent reported in 2001 that they had created something resembling the key subpopulation of magnetites in the Mars rock—and that no biological influence had been required. At the same time, they acknowledged that they had not—yet—shown that their homemade magnetites had the unique characteristics of biologically formed crystals. So the hypothesis of Martian life was still alive.

Once again, the rock had revved up lively animosities among its human hosts—and pointed the way to a harvest of new knowledge.

In the flush of renewed and often relatively upbeat attention that followed Kathie Thomas-Keprta’s Euclidean leap and the public debut of Bingo, McKay’s regulars never paused to celebrate. They were too focused on peeling the next layer of the Martian onion.

As they pushed the technologies, the team developed a new technique. Actually, it was an adaptation of an old technique, tomography, which was widely familiar from MRIs (magnetic resonance imaging) and other such nondestructive probes used in medical treatment. (
Tome
is Greek for “slice.”) Instead of having a person lie in a tunnel while the machine moved around him, Simon Clemett would put samples in the transmission electron microscope and move
them.
The effect was the same. The group would use the tomographic reconstruction to interpret the three-dimensional shape of the magnetic crystals like doctors diagnosing a patient’s innards.

Thomas-Keprta was delighted with the results. For those who said, “We don’t like your truncated hexa-octahedron,” she and Clemett felt they could hold up their tomography and let the pictures tell the story. But it still wasn’t enough.

As the debate wore on, it revolved around ever smaller and more technical details. It was science at the fringes of what could be detected. “We’re trying to solve one of the great questions by pickier and pickier details of technical analysis,” meteorite specialist Allan Treiman would lament. “Shouldn’t we be looking for much broader evidence?”

Dick Zare, advising and encouraging the McKay regulars from a distance, remarked that the whole mêlée was enough to make one’s head hurt. “How in the world am I going to teach this stuff now?” he wondered. “It’s a real frustration!”

McKay’s regulars weren’t hanging their hats on the magnetic crystals alone. McKay encouraged the group to go back to each of the original threads of evidence and see if they could push further.

For some time, McKay had been considering the possibility that the buggy shapes were organelles, or particular fragments of microorganisms, rather than whole bugs. He had a feeling that the next battlefield in the war of the rock would be the organic material. If the group was ever going to convince the wider tribe of scientists, it would have to come up with indisputable signatures of life, that is, compounds that (a) could have come only from Mars and (b) could have been created only by life. This would require more pushing of the state of the art and thinking outside the much-maligned box.

McKay was hoping to put together a narrative that tied the organics to the magnetic crystals and also to any underlying bug slime. As he pressed on through the rock with his microscope, he continued to detect fossil-like features and hollows called “molds”—places where cells might have resided but where only cavities remained.

There were cracks and veins all through the rock—cracks that had formed on Mars—and almost always when you broke the rock open along those cracks, you found some orange globs of the water-deposited carbonates, the sites where most of the interesting stuff was concentrated. But the team had also found the hydrocarbons (PAHs) in the rock (the pyroxene) itself—outside the orange carbonate moons. After intensive study of these surfaces under high magnification, McKay thought these organics might be the result of a biofilm—a kind of slime made up of microbial cells and the protective substance the cells produce. To buttress this interpretation, he would need detailed chemistry, such as the detection of well-accepted organic biomarkers called hopanes.

Then, of course, he would have to show that the biomarkers were not terrestrial, not from Antarctic melt or laboratory contamination or any other source on teeming Earth. The technology to do all this was just on the ragged edge of the possible, he knew, and it was advancing rapidly. The industrious Clemett was on the case, building new instruments.

McKay wanted to make the case. There was no denying that. But he constantly felt the need to obey the prime directive for anyone in his line of work: Make sure you are not fooling yourself.

One day in April 2002, Thomas-Keprta walked into McKay’s office and found him poring over new data. He told her, “I wanted to look at some chips and understand what I was seeing. . . . I wanted to reassure myself that what I am seeing is true, and real.”

At home, McKay’s wife and daughters treated him with new regard. When he made some little domestic decision, they were not so quick to quibble. They looked at him differently. He had, after all, taken on a world-class controversy, changed the thrust of research, weathered quadruple-bypass heart surgery, and stuck to his guns through fire, smoke, and brickbats.

In the evenings, McKay would try to forget about all of it for a few hours, to get the kinks out of his stomach. In their glass-and-cedar house in the woods, he and Mary Fae would settle in to watch TV and relax. Every now and then, Mary Fae would turn to her husband and ask, “Hey, could you be wrong about all this?” And he would lay it out one more time, and end by saying, “No, we’re not wrong.”

CHAPTER FOURTEEN

SCHADENFREUDE

A
NDREW
S
TEELE HAD
crossed an ocean and changed his life to answer the siren call of the Mars rock. He had applied himself with wit and zeal to his role as devil’s advocate for David McKay and mobilized all his fresh-minted skills to try to ferret out the secrets of life at its smallest and most primitive.

Now six years later, in the spring of 2002, this work brought Steele full circle in a sense, from the soaking waters and hot cataclysms of early Mars back to Earth during the same epoch. He could see the arguments about the potential for life on Mars intermingling, like gully washes flowing into a river channel, with arguments about the beginnings of life on the young Earth. It was a confluence that raised the general depth and breadth of the discourse but also flooded the terrain with fresh doubt—the mother’s milk of scientists.

A significant event in this flux, certainly one of the more entertaining, was about to take place in the drafty expanses of a vast dirigible hangar—large enough to contain three full-scale
Titanic
s
—
in Silicon Valley.

It was Tuesday, April 9, 2002. Steele and David McKay were part of the crowd that assembled in a state of high anticipation in Hangar 1. Built for the navy in the 1930s, the structure was part of Moffett Federal Airfield and the site of Ames Research Center, NASA’s nerve center for studies on the origin, history, and distribution of life in the cosmos. All this week, Ames was sponsoring the second annual international meeting in the emergent field of astrobiology—a field that had taken wing as a direct result of the McKay team’s 1996 announcement.

In competition with the periodic roar and whine of jets on an outside runway, many of those in attendance were buzzing about the confrontation set for this afternoon between Bill Schopf, the god of the Precambrian, and Oxford don Martin Brasier. It was almost too delicious. The venerable Brasier was daring to assail Schopf on his key discovery all those years earlier: the zoo of ancient remnants that had brought him acclaim and had long held a place of honor in textbooks and museums and the Guinness record book as Earth’s earliest known fossils.

The jousting had erupted into public view a month earlier, when Brasier published a paper in the March 7 issue of the journal
Nature.
In it, Brasier strongly suggested that Schopf had blundered when he’d claimed a biological origin for the fossil shapes he’d found in Western Australia; these “fossils” were actually imperfections in pieces of the rock that bore a faint resemblance to bacteria.
Nature
had published both the Brasier challenge and a reanalysis by Schopf, in the same issue. News of the battle had shaken the world of paleobiology.

The irony was not lost on the McKay regulars. The dispute was like a fun house–mirror image of the controversy over the Mars rock, and in particular of Schopf’s challenge to the McKay group almost six years earlier: Schopf had misconstrued nonbiological mineral shapes as fossils of living things (Brasier suggested), and the features that
might
be fossils were not the type of bacteria Schopf said they were; these fossil-like structures had not formed at moderate temperatures on a wave-washed beach as Schopf had claimed, but in a high-temperature hydrothermal vent, or hot springs; the presence of organic molecules in the structures was not necessarily a sign that these were remnants of live organisms; and so on.

The Brasier findings went a shocking step beyond merely challenging Schopf’s interpretation to allege that Schopf had failed—either deliberately or by mistake—to disclose fully in his published papers the complicated shapes of the supposed fossil structures. He had, in effect, ignored the parts of these forms that did not fit with his claims, Brasier suggested.

Brasier had set out not to attack Schopf but merely to update his textbook on microfossils. Eventually, however, he had come to the view that Schopf had failed to map the rocks in detail, study them comprehensively, or arrive at a model that fit all or most of the data. “It seems that he looked at huge numbers of samples from many sites whose story he and his colleagues simply did not understand fully, and scanned them for anything vaguely fossil-shaped,” Brasier said, adding that Schopf’s group “seem to have had an image in their minds and transposed it onto the rocks. It is a common problem in historical and material sciences, and none of us are immune from it.”

To some, this turn of events represented condign comeuppance for the tenacious and driven “Bull” Schopf, who did not suffer criticism lightly, and who, some felt, had escaped close scrutiny because of his lustrous reputation and his perceived talent for writing successful grant proposals that kept money flowing.

In a moment of particular satisfaction for the McKay team, an article about the dispute that had appeared recently in
Newsweek International
alluded to Schopf’s critique of McKay’s work on the Martian meteorite. “While Schopf and his critics go back to the [terrestrial] rocks for more and more studies,” the article said, “it’s hard to imagine the supporters of the case for the Martian meteorite fossils being so noble as to avoid a faint glow of
schadenfreude
as their foremost critic gets criticized himself.”

David McKay tried not to say anything that might sound like gloating. But Mary Fae McKay started signing her e-mail messages to friends, “With a faint glow of
schadenfreude.
”

At the very least, today’s session promised to be great theater.

Bob Hazen, a Washington, D.C.–based astrobiologist, was among those salivating at the prospect. Over lunch that day, he described the Schopf-Brasier confrontation as “Shakespearean.” The bard always made his characters kings and princes because that way they had farther to fall, Hazen mused. Now it was Schopf—god of the Precambrian, paleobiologist, geologist, microbiologist, organic geochemist, director of UCLA’s Center for the Study of Evolution and the Origin of Life, prizewinning author—who stood at the precipice.

Hazen made a point of getting to the session early. He told a companion, “I want to sit up front. I want to see the spittle.”

For Steele, the story of this extraordinary turn of events began when McKay asked him to work on his “anti-life” Blue Team, pinning down the characteristics of biomarkers—the telltale signatures that enable scientists to distinguish life from nonlife.

The two had coauthored papers together and, McKay thought, kept each other honest. Steele would prevent McKay from going too far over to unsupported claims favoring biological origins for certain features in the rock, and McKay would point out to Steele some of the finer nuances that distinguished possible Martian features from terrestrial contamination. Steele typically ran all his findings past McKay, and they looked unfailingly first-rate to the older man.

In the course of his research, Steele developed strong opinions that Schopf’s descriptions of the earliest known life were probably wrong in at least one significant aspect. Oxygen-producing cyanobacteria—Schopf’s “pond scum”—were too amazingly complex to have formed as early in Earth’s evolution as Schopf suggested. As Steele would joke, it was like giving his three-year-old a set of Legos and expecting her to construct the Parliament building. After he waxed lyrical on the topic to a friend at a meeting, word got back to Brasier, who contacted Steele. Steele was soon working with the Brasier team on the geochemical analysis of Schopf’s evidence.

The Ames meeting organizers had invited David McKay as well as Steele and others from Building 31 to give talks at other sessions during the week on new evidence or strategies related to their work on the Mars rock. In particular, they were interested in Kathie Thomas-Keprta’s intriguing magnetic crystals.

The day before, McKay had given a talk on the vital importance of bringing Martian samples back to Earth and of identifying those elusive biomarkers—measurable properties that suggest life “is or was” present—in them. As the experience with the Mars rock showed, he told his audience, “Unless we develop [better] standards, we’ll have the same trouble” when the robots come home with the new bits of Mars.

During the question-and-answer period, Baruch Blumberg stood up to speak. Blumberg had won the Nobel Prize for his discovery of the hepatitis B vaccine and was now director of the NASA Astrobiology Institute. Regarding McKay’s quest for definitive biomarkers, he said, “You may be setting up a category you’ll never find. . . . I think you’re setting yourself an impossible task.” He added, “Your data [on the Mars rock] are becoming more convincing as you go forward. This just takes time.”

McKay had adopted the Nobelist as his latest mentor. Blumberg had been even more direct recently during a private dinner. “Stop looking for the smoking gun,” Blumberg had advised McKay. “You don’t need it. You will persuade by a gradual accretion of evidence, a weight of data.”

In contrast to the months following the 1996 announcement, and despite the heart surgery, McKay looked slimmer, tan, and relaxed—whatever the bowlines and monkey fists coiled in his innards. Mary Fae admired her husband for the way he had handled the trying affair. Those closest to him thought the whole thing, having failed to kill him, had made him stronger, more confident.

McKay saw the tone of the combatants in the controversy changing. At least there was growing awareness, he thought, that the question of life signs in the rock was more complicated than anyone had dreamed. And he took pride in the fact that the flap had triggered a burst of learning on numerous fronts.

The McKay team shared a keen interest in the Brasier-Schopf shoot-out. The personal antagonism between them and Schopf had ballooned in the years since their 1996 encounter. Taking issue with the team’s hypothesis about the Mars rock was one thing. But some thought Schopf had gone beyond disagreement all the way to ridicule. This perception was not limited to McKay and his advocates. Several scientists not in McKay’s camp murmured privately that they thought Schopf had gone too far. The final chapter of his book had, as one said, “mocked the McKay group, comparing them to outright frauds.”

On Tuesday, McKay joined the crowd in the “auditorium,” actually a large white tent erected within the cavernous hangar, and took a seat. Interest was so high and the crowd so big that the organizers had relocated the confrontation from a smaller room.

Schopf, in gray turtleneck and brown pants, his name tag hanging around his neck, entered the big tent while it was in darkness, as one of the warm-up acts showed a slide presentation. Schopf hitched up his pants and waited a bit before taking a chair.

Finally, the lights came up and session moderator Jerry Lipps introduced Schopf and Brasier as “our primo speakers.” Behind him, a backdrop as big as the side of a barn depicted the cratered, icy-blue surface of a planet.

As Schopf took the stage, he asked that the lights be turned down for his slide show, adding, “I don’t need all that light on me.” His first slide showed an ancient Chinese proverb, which he read aloud: “ ‘It’s better to light a candle than to curse the darkness.’ . . . My aim here is to cast a little light on this subject with a minimum of heat.”

Schopf proceeded to demonstrate once again why he was a popular lecturer—confident, plain-spoken, emphatic, fluent. As his talk built to its finale, he would gather momentum until he was coming on like a force of nature.

Using a pointer beam, he began by showing ten of the putative fossil objects from the formation in Western Australia, which he had first reported in 1985 and formally described for publication in 1992 and 1993. The slide showed a series of dark, segmented snakelike shapes with their chemical analysis.

In his book, written before the controversy with Brasier erupted, Schopf had acknowledged that two of his graduate students, as they’d analyzed the material, had found nothing. And he himself had characterized the putative fossils as “scrappy”—charred, shredded, cooked, generally difficult to make out.

“So, the question before the house,” Schopf told the audience, “is, are these old fossils truly fossils. Either they are or they are not. Either life then existed or it did not. The job at hand is to ferret out the evidence by looking at the facts.”

Brasier stood nearby, listening intently.

It was because of the mighty impact of Schopf’s work that Brasier had felt obliged to focus on it in the first place, beginning in 1999, as he went about updating his own textbook on microfossils. Schopf’s specimens were, after all, in the
Guinness World Records
as the world’s oldest fossils—almost 3.5 billion years old. Although there was other evidence of life’s presence during the same period, Schopf’s microfossils were by far the earliest life-forms that had been reported.

Most important, as Schopf seemed to interpret them, these were not simple, primitive organisms but amazingly complex ones—the cyanobacteria (formerly known as blue-green algae) that concerned Steele. Schopf’s claims meant that life had evolved much more rapidly than previously suspected.

The claims shook theories of life’s early evolution—and also the planet Earth’s. The cyanobacteria would have pumped oxygen into the atmosphere as a by-product of their photosynthesis. And yet, geochemical evidence suggested that levels of oxygen in Earth’s atmosphere remained quite low until a billion years or so later than this. Schopf’s interpretation forced theorists to scramble to account for the incongruity.

Schopf had left his samples from the Australian site in the care of the Natural History Museum in London. They had been prepared for analysis in the usual way—cut thin enough so that a researcher could shine light through them for examination under the microscope.

As Brasier had studied these thin sections in the summer of 1999, it had struck him that there was something strange about the structures. The work was especially difficult, Brasier found, because the material containing the possible microfossils was “exceedingly complex, . . . highly broken and fragmented” and with curious fabrics not familiar to most paleontologists.