“But did anyone really expect to find anything?” I ask Geoff, as he shows me the canister that had contained his sample of moon dust from the 1969 Apollo 11 mission. “Well, no,” he replied, “we didn’t think there’d ever been life on the moon. But we didn’t know. We thought there might be organic compounds.” And why not? People had been finding organic compounds in meteorites for more than a century, and no one was quite sure where they’d come from or how they’d formed. In 1834, the Swedish chemist Jöns Jakob Berzelius noted the high carbon content of a meteorite that had fallen in southern France a couple of decades earlier. Meteor showers in Europe were described as early as 1492, and their extraterrestrial provenance had been documented in 1803, when the distinguished French physicist Jean-Baptiste Biot featured among the scores of citizens who witnessed the stones falling from the sky above the village of l’Alsace. But the source of the carbon compounds Berzelius and others found in meteorites would remain controversial far into the next century. Another carbonaceous meteorite fell in Hungary in 1857, and the eminent chemist Frederick Wöhler—Berzelius’s student, and the first to show that one could create carbon compounds like those made by organisms from inorganic substances in the lab—found organic compounds that he was convinced were of extraterrestrial biological origin. A decade later, Marcellin Berthelot found what he called “petroleum-like hydrocarbons” in a meteorite that had fallen near Orgueil, France, in 1864. He postulated that the hydrocarbons had formed abiotically from reaction of metal carbides with water, but in the next few years there was a spate of meteorite treatises in which the fossils of an astounding assortment of exotic extraterrestrial creatures were described in minute detail. Louis Pasteur had just presented his famous experiment showing that a protected, sterile medium remained devoid of life ad infinitum and debunked the popular theory that life could burst spontaneously into being from nonliving matter, but now the debate shifted to the possibility that life on Earth had originated with live cells or spores delivered by meteorites from space.
LOUPE: Observing the Earth from the Moon to prepare for detecting life on Earth-like exoplanets