For at least 12 centuries, the oracle at Delphi spoke on behalf of the gods, advising rulers, citizens and philosophers on everything from their sex lives to affairs of state. The oracle was always a woman, her divine utterances made in response to a petitioner's request. In a trance, at times in a frenzy, she would answer questions, give orders and make prophecies.
Modern scholarship long ago dismissed as false the explanation that the ancient Greeks gave for the oracle's inspiration, vapors rising from the temple's floor. They found no underlying fissure or possible source of intoxicants. Experts concluded that the vapors were mythical, like much else about the site.
Now, however, a geologist, an archaeologist, a chemist and a toxicologist have teamed up to produce a wealth of evidence suggesting the ancients had it exactly right. The region's underlying rocks turn out to be composed of oily limestone fractured by two hidden faults that cross exactly under the ruined temple, creating a path by which petrochemical fumes could rise to the surface to help induce visions.
