head-on collision tagged posts

This image shows from left Paul Warren, Edward Young and Issaku Kohl. Young is holding a sample of a rock from the moon. Credit: Christelle Snow/UCLA

The moon was formed from a violent, head-on collision between early Earth and ‘planetary embryo’ called Theia ~100 million years after the Earth formed, almost 4.5 billion years ago. Many thought Earth collided with Theia at 45 degrees or more. New evidence substantially strengthens the case for a head-on assault.

The researchers analyzed seven rocks brought to the Earth from the moon by the Apollo 12, 15 and 17 missions, as well as 6 volcanic rocks from the Earth’s mantle – 5 from Hawaii and 1 from Arizona. The key to reconstructing the giant impact was a chemical signature in the rocks’ O atoms...