Space & Astronomy

The Earth is actually two planets - not one

By T.K. Randall
January 29, 2016 ·  27 comments

The early Earth was involved in a massive planetary collision. Image Credit: NASA/JPL-Caltech Somewhere around 100 million years after the Earth was formed it had a run-in with another planet known as Theia, but while previous studies had suggested that the two worlds had only side-swiped one another, new research has revealed that they were most likely involved in a head-on collision.

The cataclysmic smash was so destructive that Theia was reduced to a cloud of debris which gradually merged together with the Earth to form both the moon and a single, larger planet.The research was based on a new analysis of rock samples retrieved during the Apollo moon landings which showed an identical ratio of oxygen isotopes to materials collected on the Earth - something that shouldn't be possible if the Earth and Theia had only side-swiped one another.

"Theia was thoroughly mixed into both the Earth and the moon, and evenly dispersed between them," said UCLA geochemist Edward Young.

"This explains why we don't see a different signature of Theia in the moon versus the Earth."


Source: Red Orbit | Comments (27)

Tags: Moon, Earth, Theia