Two worlds collide Credit: Stocktrek Images

The giant impact hypothesis — the popular belief that a “planetary embryo” called Theia collided with Earth some 4.5 billion years ago, leading to the formation of our planet’s moon — has been around for a while.

But a NASA-funded research team has added an amazing new twist to the idea; that Earth wasn’t just sideswiped by Theia, as many have conjectured, but sustained a direct hit and actually absorbed a large portion of the rogue planet.

In other words, Earth is made up of two fused planets — Earth and Theia — the study suggests.

“Theia was thoroughly mixed into both the Earth and the moon, and evenly dispersed between them,” lead author Edward Young, a professor at the University of California, Los Angeles, said in a statement.

For their study, the UCLA-led team compared the chemical signatures of moon rocks with volcanic rocks from Hawaii and Arizona.

If Earth and Theia had collided in a glancing side blow, as the […]