Are Earth's Oceans Made Of Extraterrestrial Material?

Contrary to preconceived notions, the atmosphere and the oceans were perhaps not formed from vapors emitted during intense volcanism at the dawning of our planet. Francis Albarède of the Laboratoire des Sciences de la Terre (CNRS / ENS Lyon / Université Claude Bernard) suggests that water was not part of the Earth's initial inventory but stems from the turbulence caused in the outer Solar System by giant planets. Ice-covered asteroids thus reached the Earth around one hundred million years after the birth of the planets.

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