Earth's Water Likely Came From Very Early Asteroid Strikes

Earth got most of its water from asteroid impacts nearly 4.6 billion years ago, shortly after the solar system first took shape, a new study suggests.

Researchers studying a meteorite that fell to Earth in 2000 found evidence that the water in its parent asteroid disappeared soon after the space rock formed, when its insides were still warm. Asteroids that slammed into Earth several hundred million years after the solar system's birth were thus probably relatively dry, scientists said.

"So, our results suggest that the water [was] supplied to Earth in the period when planets formed rather than the period of late heavy bombardment from 4.1 billion years to 3.8 billion years ago," study lead author Yuki Kimura, of Tohoku University in Japan, told LiveScience via email Read more...