The Prestigious Scientist Who Theorized That Oil Comes from Another World Inside Earth
Thomas Gold was a deep thinker. A fellow of eight distinguished scientific organizations and a winner of numerous prestigious prizes, the Austrian-born American astrophysicist poured his heart and mind into science. Working out of Cornell University for much of his career, Gold published dozens of papers in astronomy and geophysics, thought up many ingenious, often controversial theories, helped establish the now iconic Arecibo Observatory in Puerto Rico, and hired a budding 34-year-old astrophysicist by the name of Carl Sagan.
Noted for his willingness to venture down the metaphorical rabbit hole, Gold climbed down a particularly deep one in the latter half of his life. By the 1970s, scientists broadly accepted that oil was of a biological origin. Labeling oil a "fossil fuel," they theorized that deceased algae and plankton sank to the bottom of oceans and, over millions of years were slowly transformed into oil by pressure and heat. Gold wasn't so sure.
Noticing that hydrocarbons, organic compounds of hydrogen and carbon, are present on and in other astronomical bodies, Gold reasoned that Earth's oil might originate from nonliving sources instead of living ones. He argued that an unfathomable amount of hydrocarbons were locked within Earth, and that as they seeped upwards, they were converted to oil and gas. He eventually outlined his theory in a book, The Deep Hot Biosphere, making two other fantastical propositions as well:
"that below the surface of the earth is a biosphere of greater mass and volume than the biosphere the total sum of living things on our planet's continents and in its oceans... [and] that the inhabitants of this subterranean biosphere are not plants or animals as we know them, but heat-loving bacteria that survive on a diet consisting solely of hydrocarbons that is, natural gas and petroleum."
In short, Gold claimed that within our world lies another world! An undeniably exciting prospect, there is currently no meaningful method of exploring it. Without evidence, a deep hot biosphere remains in the realm of fiction. We can, however, examine Gold's original claim, that oil and gas are not fossil fuels, that they are instead abiotic.
To his credit, Gold spent years molding and testing his idea. First conceiving of the theory in the 1950s, he let it simmer in his brain for around twenty years before finally fleshing it out. In numerous published works he contended that the movement of tectonic plates and faults allowed methane to migrate up into the mantle, where, through cooling and other processes, it would transform into crude oil.
In 1986, Gold used his influential standing to procure $40 million for a drilling expedition in a 360 million-year-old impact crater near Lake Siljan in Sweden. This would be his moment.
According to Gold's theory, abiotic oil should have been present below the crater in great quantities. It wasn't. Despite drilling down over six kilometers in two locations, the costly operation turned up just 80 barrels of oil over six years, and there was no definitive proof that it was abiotic in origin.
Empty-handed, and limited by the technology available, Gold could only return to theorizing. He speculated that the oil he recovered in Sweden may have started as hydrocarbons from a deep biosphere, then were converted to oil by deep-dwelling thermophilic bacteria. Additional knowledge of the Earth's mantle procured years later would provide critical evidence against his theory of abiotic oil. According to the University of Tokyo's Geoffrey Glasby:
"Methane can only be converted to higher hydrocarbons at pressures >30 kbar corresponding to a depth of ~100 km below the Earth's surface. The proposed reaction of methane to produce higher hydrocarbons above this depth and, in particular, in the upper layers of the Earth's crust is therefore not consistent with the second law of thermodynamics."
Despite the evidence against Gold's theory of abiotic oil, it cannot be completely ruled out. Though the weight of evidence supports a fossil fuel origin of oil and gas, most geologists admit there's still a tiny chance it might be wrong. Abiotic oil could very well exist, perhaps in small quantities.