The strange Heresies of Thomas gold

Sometime next year, from off the coast of Japan, we should find out if he is right. Working onboard the Chikyu, a 210-meter ship equipped with a huge drilling platform, a team of geologists, engineers and oceanographers led by Japan's Center for Deep Earth Exploration hopes to drill the world's deepest hole. The 8.5-inch aperture will penetrate seven kilometers under the earth's crust to pierce its mantle and solve some of our most profound mysteries. For the first time, human eyes may see the molten rock that makes up 84 percent of Earth's volume. According to astronomer Thomas Gold, they may tap into the source of the planet's energy and the cradle of life itself.

If correct, Gold's theory will change the way we think about everything from energy to our role in the universe. Corporate and state power contingent on the vagaries of the oil market could disintegrate. Environmental policies would have to adjust to a new paradigm. Even cultural values premised on the uniqueness of life would have to be made anew. For decades Gold's theory has enraged the scientific establishment. "Every fact is against him," says an Amoco geochemist. "Completely absurd," adds a Colorado School of Mines geologist. "A waste of time," says another, "on about the same level as saying sugarplum fairies will cure cancer."

Thomas Gold typically generates these sorts of responses. An iconoclast astronomer educated at Cambridge University, Gold spent his career challenging conventional wisdom with ideas on everything from the nature of the universe to the workings of the inner ear. Controversy has been common with Gold, but the response was never more explosive than it was to his theory about the secrets of the mantle. He put forth his most heretical theory after he retired from Cornell University, in 1987. His critics contended he had aged into a wild crank; an unrepentant Gold defended his theory until he died last year, at the age of 84, in Ithaca, New York. Will the world's deepest hole be Gold's final redemption, or will it sound the death knell for his long-challenged theory?

Gold's idea was at first simple. Scientists have envisioned the earth as a sterile chunk of molten rock with a surface civilized by a film of life that processed elements into complex molecules. Over time some of these products of living chemistry were rescrambled into molecules such as methane and octane and other hydrocarbons otherwise known as petroleum, which all rest within the first few kilometers of the earth's eggshell-like crust.

Along with astrophysicist Steven Soter, Gold proposed a modified scenario in 1980. After hydrocarbons--in particular methane, the main component of natural gas--had been found on Jupiter and the moons of Saturn, Gold and Soter hypothesized that the earth, too, might have been endowed with methane and other hydrocarbons long before life came around. Primordial abiotic hydrocarbons--i.e., molecules not created biologically--might bubble up to mingle with biologically generated hydrocarbons. If so, their serpentine movements through cracks and fissures in the crust would explain their mysterious presence at the bottom of certain lakes and steaming out of hydrothermal vents.

It was, they admitted, a relatively simple hypothesis. It would "doubtless turn out to be in places oversimplified and overstated," but they hoped it would at least spur research. They added a few throwaway lines--a half dozen in a five-page article--about the possibility of abiotic hydrocarbons furnishing a source of energy. It was interesting to ponder but not a practical concern. Nobody had ever drilled deeply into the crust, let alone the mantle underneath it. Why bother? The best oil fields in the world offer oil and gas from holes that are just three kilometers deep. Even a hole twice that depth would cost upwards of $4 million to drill.

The implications of Gold's theory are profound. According to the Department of Energy, the planet's natural-gas supply is fixed somewhere around a half trillion barrels of oil. If Gold is right, such estimates are off by several orders of magnitude. Instead "there would be an inexhaustible supply," says industry geologist Barry Katz. What that may mean for a civilization whose progress is defined by finite energy resources boggles the mind. "It's the golden fleece," says Katz.

It wasn't long before libertarian economists and conspiracy theorists latched onto Gold's hypothesis. "The world is running into oil, not out of it," claimed energy economist Peter Odell, who went on to say that the OPEC-induced energy crisis of the 1970s was driven by market forces. He felt there was no need to fear, because by 2060 "abiogenic oil will, if need be, enter the market."

Gold wasn't particularly interested in the economic implications of his theory. "It was pretty clear that exploitable deposits are very different from an abundance of inaccessible material," says Gold's colleague astrophysicist Edwin Salpeter. "Gold usually stressed the scientific implications more than the economic ones," adds Soter. Then again, Gold had a tendency to exaggerate for effect.

From the beginning of his career, Gold was the sort of genius who irritated other scientists. Over and over he invaded new fields and challenged basic principles, offering little more than incisive logic and qualitative evidence done in broad strokes. Born in Vienna in 1920, Gold fit the part of the maverick. A few years after qualifying to ski professionally in Switzerland, he went to Cambridge, where (continued on page 150) Thomas Gold(continued from page 106) as a master's student at Trinity College he shocked the medical establishment with a theory of hearing that challenged Hermann von Helmholtz's accepted theory. The inner ear, Gold claimed, generated its own tone. He was laughed out of medicine. By the age of 28, he had moved on to astronomy. In 1948 he and two fellow graduate students, Fred Hoyle and Hermann Bondi, presented a new theory of the nature of the universe. Their steady-state theory reigned for years before being supplanted by the big bang.

In 1959 Gold was appointed John L. Wetherill Professor of Astronomy at Cornell. His bold ideas continued to earn him enemies. By the late 1960s conference organizers had become so enraged with Gold's contrarianism--this time his theory was that recently discovered pulsars were actually rotating neutron stars--that they refused to allow him five minutes to speak from the floor.

The rub was that, more often than not, Gold was right. His theories on hearing and pulsars are now accepted wisdom. Sure, he didn't bother much with details, but "he was undeniably brilliant," says geologist Barbara Sherwood Lollar. "He always advocated theories that were unorthodox," says Salpeter, "and many turned out to be right."

By the time he turned his attention to geology, Gold was a towering figure. Along with being chairman of astronomy at Cornell, where he had hired Carl Sagan, Gold was a member of the National Academy of Sciences and director of Cornell's Center for Radiophysics and Space Research. "In person he was a polite European fellow," remembers former Cornell grad student Thomas Zemanian. He charmed acolytes with his Viennese accent and his mad-scientist enthusiasm. He skied the Aspen slalom course every year--and in gold-medal times. "He didn't suffer fools," says U.S. Geological Survey geologist emeritus David G. Howell, "and he didn't worry if people disagreed with him."

In 1966, as NASA prepared to send astronauts to the moon, Gold calculated that contrary to geologists' prediction of a rocky lunar surface--the condition astronauts trained for--the moon would be covered in a fine powder. "Most geologists said, 'Absolutely not. There's no moon dust, not even a hundred-millionth of an inch of dust,'" says Salpeter. "Tommy would exaggerate a little and say, 'Look, the astronauts will sink in to their navels.'" Geologists complain that NASA spent six of seven surveyor missions attempting to find out if its manned mission might sink in dust. Kenneth Deffeyes, a petroleum geologist at Princeton, was appalled. "That was a big, multibillion-dollar program," he says, "and most of it was spent refuting Gold's idea." In the end, as was often the case, Gold was both right and wrong. The astronauts sank in dust up to their ankles. "So the geologists said, 'He was wrong!'" says Salpeter. "But the geologists were completely wrong by a factor of 100 million. Gold was wrong by a factor of three."

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Then Gold came up with another outrageous theory: that petroleum resided not just in the crust, where oil explorers spent their time hunting for it, but at far greater depths, in the mantle. When energy analyst Gregg Marland gathered geologists in Oak Ridge, Tennessee in 1983 to discuss the abiotic-gas theory with Gold, tensions were running high. Astronomers and physicists might have found Gold's theory reasonable enough, but most petroleum geologists thought it was ridiculous. There were obvious scientific objections: Hydrocarbons would be destroyed at the high temperatures and pressures of the mantle, for one thing. Geochemists, furthermore, had their reputation to consider; energy agencies and oil and gas companies funded their research because it was supposed to help find oil and gas, yet according to a 1975 study, just as much oil and gas would have been found if the holes had been drilled at random. Since then they had worked to build a solid theory of hydrocarbon formation, and they weren't about to let Gold shoot holes in it.

The three-day meeting quickly devolved into confrontation. Gold was unhappy during much of it. "He felt he was outnumbered and picked on," said Marland. Amoco's John Winters left the meeting saying he would never again speak publicly with Gold because the esteemed astronomer was "out of the realm of rational science." "I've never been at a meeting quite of this character," said the moderator, Alvin Weinberg.

"People shake their fists at me," Gold told one magazine. "If they could, they would burn me at the stake." Despite all the rancor, no one disputed that Gold's deep abiotic gas existed.

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Geochemist Michael Lewan worked with Winters at Amoco in the 1980s, analyzing organic-rich rock and running lab experiments on how to turn it into oil. "I don't think anybody has ever doubted there is an inorganic source of gaseous hydrocarbons," he says. Another geologist acknowledges, "I have no problem with the idea that there is abiogenic methane." Gold's theory had exceeded the boundaries of petroleum geology. If the stuff was down there, it was probably dispersed and certainly deeply buried. Nobody could see how to make a buck finding and selling such gas, so it was irrelevant, no matter how enlightening.

But Gold kept pushing. Hadn't geologists similarly excoriated meteorologist Alfred Wegener's 1915 theory of continental drift, mocking it for 50 years before it was accepted? "I don't think I have anything to apologize for," he said to The Vancouver Sun. "I am almost always right." As geologists' resistance grew, so did Gold's claims about abiotic gas. In 1980 Gold and Soter wrote that "much of the petroleum that has been recovered" originated from the burial of biological debris. By 1986 he was telling reporters that only some oil and gas originated from biological materials. By 1999, in his second book on the topic, Gold claimed that no oil came from biological debris, although he allowed that some gas did.

As a science, geology lacks both a consistent experimental method and a vigorous theoretical wing. This has led some physicists, as one academic geologist notes, to "sometimes think we're dumb." But petroleum geology is perhaps the most advanced subdiscipline within the field. And the story of hydrocarbons has been told many times. According to petroleum geologists, hydrocarbons start to form when sediments enriched with the corpses of organisms--mostly plankton--get slowly buried. As the sedimentary layer sinks to 7,500 feet or so, the pressure and heat are right for sediments to turn, over millions of years, into oil-rich rock. (If sediments slip deeper than 18,000 feet, heat and pressure destroy the oily molecules.) Tectonic movements force the oil in sedimentary rock into circuitous movements in the crust. If the migrating oil meets up with a porous rock with a solid cap on it, it will get trapped. The lucky driller who pierces that rock gets a Cadillac.

A wide array of evidence supports this three-act story of burial, migration and entrapment. Pieces of chlorophyll and shell are found in oil and gas. Trails of high electrical resistivity can be used to track oil and gas migrations underground. One can even heat a lump of organic-rich sedimentary rock in the lab and turn it into oil. Finally, nearly every oil and gas field has been found not in lifeless igneous rocks thrust up from the mantle, where Gold's abiotic gas supposedly resides, but in sedimentary rocks formed from material sloughed off from the life-teeming land and seas.

Gold had an alternate explanation for nearly every piece of evidence petroleum geologists put forward to defend their biotic theories. The microfossils in oil? Microbial contamination after the fact, he said. Evidence of migration? Irrelevant, he said, because abiotic hydrocarbons drifting up from the mantle would move in the crust the same way biotic ones did. Ditto for the transformation of organic sedimentary rock into petroleum. The rock had already soaked up abiotic hydrocarbons. Sedimentary rocks as the primary locale for oil and gas fields? Self-fulfilling prophecy, he said. Nobody bothered to look in igneous rocks.

And yet, save for a few stray supporters such as David G. Howell and independent oil explorers Michel Halbouty and Robert Hefner, Gold's claims fell on deaf ears. "I think 95 percent of professional geologists would disagree with Gold," says one University of Southern California petroleum engineer. Gold needed evidence. He needed to discover hydrocarbons in a place where they couldn't possibly have formed biologically.

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Gold found a receptive audience in Sweden. In the mid-1980s, energy officials there could be described as desperate. Sweden's environmentally concerned populace had condemned the nuclear reactors that had powered the country since the early 1970s. With no known domestic source of oil, gas or coal, however, it remained unclear how the Swedes might replace nuclear power. But Sweden did have the Siljan Ring, a perfect test site for Gold's inorganic-gas theory. Nearly 400 million years ago a three-kilometer-wide meteor crashed into the crust there, fracturing it to a depth of 50 kilometers and leaving behind Europe's second-largest crater. No organic sediments were present to have produced oil, gas or coal in the traditional way, but the cracks could have allowed Gold's inorganic gas to bubble up. Gold had suggested the notion to Swedish officials in the early 1980s, and after some research they decided to drill a $25 million, six-kilometer-deep hole in the crater to search for the gas. Then the state power board's advisory committee issued a report calling the chances of success remote. Although the notion of mining the sites of meteor strikes wasn't unheard of--others had proposed drilling to tap into geothermally heated water--some officials worried the country might appear foolish. The government pulled the plug on the funding.

Gold remained determined. A private holding company was set up to fund the project in partnership with government agencies. With talk of a $100 billion reserve, people anted up, and drilling began in June 1986. Gold's detractors weren't impressed. In their eyes Gold had crossed the line from science into boosterism. Forbes ran an article reporting that Gold had received $640,000 for the drilling. According to the magazine, an American drilling supervisor mistakenly announced on Swedish TV that the hole had produced a massive reservoir. Within months share prices had risen from 10,000 kronor to 107,000.

The rock proved unyielding. By September 1986, after plowing through 6.3 kilometers, the drillers had found only a small bit of oily sludge. Gold claimed victory--"my theory is now on much firmer ground," he said--but skeptics chalked it up to contamination from drilling fluids. The drilling contractor abandoned the hole and pleaded bankruptcy.

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While geologists cheered Gold's failure, across the Atlantic in Ontario methane was streaming out of the same kinds of Precambrian granite Gold had drilled in Sweden. Since the turn of the century Canadian miners had told tales of flammable gases wafting out of their mines, miles away from any ancient biological debris. "But nobody had tackled it scientifically," remembers Barbara Sherwood Lollar, then a Ph.D. candidate in geology at the University of Waterloo. "All this press and money were going into the Siljan," she says. "Then a couple of people here in Canada said, 'We know the gas is here. Let's go to the mines and take some samples.'" Punching a hole into the wall of the mine, she says, was like opening a can of soda. There was gas in the rock everywhere.

Sherwood Lollar set to work analyzing the gas, but she ultimately turned to other research. Definitive data on the gases wouldn't emerge from her work for years. As a young academic interested in securing tenure, "you want to be sure you're not working in an area that some people would feel is crackpot," she says. Gold had "given the field a black eye. People heard 'abiotic gas' and put you into the category of crank."

Other evidence emerged at Cornell. Thomas Zemanian, then a grad student, spent five years building an apparatus to test if hydrocarbons could be stabilized by pressures of the mantle, as Gold had speculated. By 1989 he had, contrary to expectation, proved they could. But when he sent out his paper for publication, the anonymous peer reviewers were livid. Zemanian moved on to other things. Trying to support Gold's theory with experimental data--the lack of which continued to condemn it in scientific circles--"just isn't the kind of thing that pays the bills," he says. Zemanian now works for the Department of Energy's Pacific Northwest National Lab. His Cornell research remains unpublished.

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Gold plugged away in Sweden. "He was a believer in this idea," says Howell, "and because of the resistance and because he had retired, he kind of became evangelical." More money was drummed up for another project. In 1991 Gold extolled the Siljan region as a "world-class prospecting area for gas and oil" with a total volume "bigger than the volume of the Kuwaiti oil fields." But that hole also rendered inconclusive results. Out came a small quantity of oily sludge, which caused the same old squabbles: Gold claimed vindication; critics dismissed his find as the result of contamination from distant sediments or drilling fluids.

But then Gold found something in the hole. More than 50 kilograms of a stiff black putty had oozed up from the bottom of the fissure. Drillers, judging it an "uninteresting, malodorous nuisance of no commercial value," as Gold put it, had thrown most of it away. But Gold got his hands on a small plastic bag's worth, which he set about analyzing. What he found was of "extraordinary scientific value," he later wrote. It was magnetite.

A magnetic form of iron, magnetite is found in igneous and sedimentary rocks, mostly in large crystals. Geochemists scoffed that the stuff Gold found was only a by-product of lubricants used in the drilling, but Gold thought otherwise. Something had processed this magnetite--it was particularly fine-grained--and dumped it down there. It was time for another radical proposition.

In the early 1980s Gold developed a theory of what he called the deep hot biosphere. Accepted wisdom held that all life requires sunlight, but Gold didn't see any plausible reason for that. If inorganic gases had been welling up from the mantle for millennia, as he believed, some microbe must have emerged to feed on them. To figure it out, "you or I would probably start reading the literature," says John Zollweg, a researcher who worked with Gold at Cornell. "But that wasn't Tommy's approach. His was 'I'm a cosmologist. Let me think about things.'"

There had been hints that microbial life might exist in the depths. Since the 1930s oil drillers had claimed to have found microbes in their oil wells. In the late 1970s all manner of bizarre life-forms were found around "black smokers"--fissures in the seafloor that stream superheated liquids from below--in waters far too deep for sunlight to penetrate. Clearly the world of microbes had barely been charted. In 1977 microbiologist Carl Woese discovered not just a few new species of microbes but an entirely new kingdom: the archaea.

What if these creatures were not thrilling extensions of surface life, Gold asked, but represented some unknown biosphere in the rocks? What if life evolved not on the surface but from down below? In fact, Gold speculated, the subsurface of the planet provided an ideal nursery for early life. It was vast, warm and--if one accepted Gold's theory about inorganic gases--energy rich, too. Gold figured that if microbes were present in just the first six kilometers, even if they were as rare as Siberian tigers, their empire would be at least as big--if not bigger--than our familiar one in the light. 'Just imagine the volume" of a deep biosphere, says microbial geochemist Jan Amend. "The subsurface could harbor more living carbon than all the green plants, soil bugs and ocean critters combined."

Gold considered geology parochial because it painted Earth as unique. He viewed Earth as one planet among many, unique in some ways, ordinary in others. Conditions inside our planet are not unique, Gold knew. "Two or three miles down," says Cornell soil ecologist David Wolfe, "at least a few planetary bodies in our solar system are almost identical to Earth." If there were a deep hot biosphere on Earth, there could be more on other planets rotating around our sun. If Gold is right, scientists shouldn't look for extraterrestrial life on planetary bodies; they should look inside them.

The basis for Gold's bold conjectures was questionable at best. The supposed deep oil microbes had been dismissed as contaminants from the drill bit or elsewhere. In the early 1980s Carl Woese's methodology wasn't held in high regard in the scientific community. Rather than coaxing his microbes to survive in his lab, where they could be studied, Woese presumed their existence by analyzing bits of nucleic acid--RNA--in his samples. Black-smoker ecosystems were dark, true, but ultimately they too depended on life-giving sunlight. Their oxygenated seawater came thanks to the exertions of sun-loving plant life.

In the 19th century Charles Darwin suggested that life may have originated in a "warm little pond, with all sorts of ammonia and phosphoric salts, lights, heat, electricity, etc., present." Lab simulations of the warm little pond seemed to support Darwin's scenario. According to Gold's friend Fred Hoyle, the notion that something as complex and ther-modynamically improbable as life could form out of a bit of ooze was about as believable as a jet airliner being assembled during a hurricane in a junkyard. But that was the story, and the scientific establishment was sticking to it. In 1983 Gold submitted his paper on the deep hot biosphere to Nature. It was rejected.

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By the 1980s the certainties around the origin of life, the planet's energy budget and the scale of microbial life had started to crumble. A series of discoveries suggested the early earth was more forbidding than had been thought. Meteor craters were found on the moon, much larger and older than those on earth. If the early solar system was as violent as the moon scars suggest, geologists said, the earth could not have escaped unscathed. Yet fossil evidence established that photosynthesizing life-forms emerged not long after an active meteor period. This didn't add up. Such meteors would have sterilized the surface for thousands of years. Life's first ancestors could have survived only if they had been entrenched in some deep, hidden corner. Nobody knew where that corner might be--hydrothermal vents were one suggestion--but many agreed that Darwin's little pond was no longer so welcoming.

The accepted view on the planet's endowment of methane and microbes had also been called into doubt. In the late 1980s government geologists discovered that the planet's seafloors and permafrost were littered with icelike compounds called methane hydrates. Previously thought to exist only in the solar system's outer reaches, methane hydrates form when methane leaks out into cold, high-pressure conditions. If there was as much methane hydrate on earth as there appeared to be, the planet must hold 100 times more methane than previously believed. The same goes for microbes. As the molecular techniques Woese had been scorned for came to be accepted, microbiologists discovered they had underestimated the extent of the microbial world by a factor of 100. To top it off, microbiologist Derek Lovley had isolated a new microbe from the bottom of the Potomac River in 1987. It breathed rust and excreted magnetite.

In 1992 Gold exercised his privilege as a member of the National Academy of Sciences to get his paper on the deep hot biosphere published in the academy's journal without peer review. The paper dropped like a bomb onto fields ranging from microbiology to astronomy and oceanography. USA Today ran a front-page article. If there were a deep hot biosphere, it "could prove to be one of the monumental discoveries of our age," Physics World wrote. Not everybody was so charged up. "A lot of people just said, 'Rubbish,'" says University of Washington astrobiologist Roger Buick. "We do not yet have enough solid observations to say this is so," a microbiologist told The New York Times. The idea of a living kingdom deep in the crust may have sparked imaginations, but few scientists had the wherewithal to actually look for it.

Three years later, thanks to energy officials worried about microbes eating through buried nuclear waste containers, the kind of ecosystem Gold had envisioned--living things requiring no sun, no oxygen and nothing that resulted from the two--was found. In 1995 scientists from the Pacific Northwest Laboratory analyzed samples from wells dug into a layer of hardened lava called the Columbia River basalts. The amazing thing wasn't that they found evidence of microbes there but the kind of microbes they appeared to be. These organisms could live in the oxygen-starved darkness by feeding on hydrogen. This "subsurface lithoautotrophic microbial ecosystem" (or SLiME) lived off abiotic gases in the lifeless rock alone.

The hunt was on for the deep hot biosphere. In 1997 the National Science Foundation earmarked $6 million a year for inquiries into life in extreme environments--in scalding hydrothermal vents, under miles of ice and deep underground. In 1998 NASA created the Astrobiology Institute, doling out $15 million a year to search for the origins of life. One arm of it was devoted to drilling deep into the earth's crust. Searching for life under the seafloor likewise rose to the top of the Ocean Drilling Program's research agenda.

Experimental evidence of a deep hot biosphere started to accumulate quickly. In 1998 Princeton geomicrobiologist Tullis Onstott found microbes living 2.7 kilometers underground in eastern Virginia. Later he discovered signs of microbial life more than 3.5 kilometers down in a South African gold mine. In June 1998 one of Woese's protégés, a University of Georgia microbiologist, calculated that the underground biomass could equal all the planet's marine and land plants. In 2002 another deeply buried SLiME was discovered. In the pore spaces of igneous rock under Lidy Hot Springs in Idaho, microbes were feeding on hydrogen produced by reactions between hot water and rock, exhaling methane.

While most of these deep microbial worlds exploit the interior's production of hydrogen rather than methane, evidence suggests that methane too is abundant in the crust, formed inorganically as Gold had suggested. In 1999 chemists at Oak Ridge exposed iron-rich rocks to seawater under conditions similar to those beneath the ocean and produced methane. Sherwood Lollar's mysterious gases in the Canadian Shield were similarly formed in the water-filled fractures of ancient rocks. As scientists looked for the microbial world they guessed might be feeding on methane, oceanographers inadvertently discovered just that in the spring of 2005, nearly a kilometer under the Atlantic. At the Lost City hydrothermal field of 60-meter-tall creamy white spires and cliffs, seawater trickling into iron-rich mantle rocks exudes life-giving methane and other gases. Scientists still don't know how life originated, but as for where, they are closer to an answer: Look down.

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Even as evidence grew for the deep hot biosphere, Gold's theory of abiotic hydrocarbons remained an object of derision in geological circles. In 1993, for example, when the U.S. Geological Survey published a collection on natural gas that included a contribution from Gold, dozens of irate academic and industry geologists petitioned the agency. "They wanted me fired, and they wanted the book withdrawn," says Howell, who spearheaded the project. Gold responded by filing a $1 billion lawsuit against 36 industry and academic geologists for libel, assault and slander. The suit was dismissed shortly afterward.

Gold's critics didn't bother to read his books, either. "It was more than I had time for," says Lewan. Kenneth Deffeyes also admits he never read Gold's books. A 2004 textbook penned by geologists from the USGS, Stanford and Exxon-Mobil recalls Gold as a misguided scientist and notes that his abiotic-gas theory was criticized by "nearly all geochemists and petroleum geologists." The deep-hot-biosphere theory was in "conflict with conventional concepts of the earth's biosphere." Gold's theory kept making the rounds only because its supporters "use many of the same tactics the supporters of scientific creationism use to ridicule evolutionary theory." To detractors such as industry geologist Katz, the study of abiotic hydrocarbons isn't even real science. "It's almost like a religion with some of these people," he says. "This is something a lot of people want to believe," adds Deffeyes, "because, wow, oil fields will refill themselves; we will just drill deeper, and there won't be any problem."

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Nobody knows whether a huge store of methane lies deep in the mantle. All scientists can say with certainty today is that the methane we do have is primarily biologically derived, with a smaller amount created inorganically in the crust. The deep methane could be there and we just haven't been able to access it yet. Perhaps we never will. The need to prepare for a postpetroleum age has probably become urgent enough to render moot hunts for elusive reserves of gas. But new endeavors to study the depths continue apace. In Sweden, microbiologist Karsten Pedersen hopes to circumvent the problems of contamination and pressure differentials that plague deep research by plugging directly into the deep biosphere. Blessed with ample funding through Sweden's nuclear-research program, Pedersen is studying deep microbes from a lab situated in a man-made cave system carved 500 meters under the granite.

And the scientific community awaits the results from the Chikyu. It may take a year for the drilling to reach the mantle, but many of the scientists involved expect to find life there. What we will learn remains to be seen. What's clear is that over the course of a few decades, Gold's heretical ideas have effected a revolution in our understanding of our place in the universe.

By the late 1990s the indomitable professor had stopped skiing. "He had bad arthritis in his hands," says Howell. "He wasn't as astute in conversation." But his scientific conviction never faltered. "He was championing his theories right up until he went to the hospital," says Robert Hefner. Gold died in June 2004.

Today few scientists doubt the existence of the deep hot biosphere. And deep microbial life feeding on abiotic gases may be the rule, not the exception, inside planets similar to ours. It's another ego-bruising blow: First Copernicus told us the sun didn't revolve around us, then Darwin said we descended from animals. Now it appears we're not the lead characters on the main stage of life; we're just a sideshow. Thomas Gold wasn't right on all the details--not by a long shot--but then again, few revolutionaries are.