As NASA astronauts aim for landings in 2027, geologists find surprises in recently retrieved samples from the far ...

The Moon likely formed from the remnants of a colossal collision between the proto-Earth and a Mars-sized body named Theia around 4.5 billion years ago. The impact ejected vast amounts of molten ...

Before Earth and the Moon, there were proto-Earth and Theia (a roughly Mars-sized planet). The giant-impact model suggests that at some point in Earth's very early history, these two bodies collided.

This last collision, also known as the “moon-forming impact,” was so large that—in addition to adding lots of material to the Earth—there was enough energy to vaporize some of the rock and metal from ...

The moon is thought to be the aftermath of a giant ... involving a Mars-sized 'Theia' and proto-Earth. In this image, the proposed hit-and-run collision is simulated in 3D, shown about an hour ...

Over time, this debris coalesced to form the Moon. We do not know for sure if Theia existed and if it collided with the young proto-Earth, but the evidence is compelling. For one, we are the only ...