The giant-impact hypothesis posits that billions of years ago a Mars-sized body named Theia collided with the early Earth.

A detailed simulation of Theia crashing into Earth. While the collision was violent, it was not energetic enough to melt the Earth's lower mantle -- meaning that remnants of Theia could be ...

These structures are theorized to contain remnants of Theia's materials, offering valuable insights into the ancient collision. The presence of large low-velocity provinces in Earth's mantle ...

In this image, the proposed hit-and-run collision is simulated in 3D, shown about an hour after impact. A cut-away view shows the iron cores. Theia (or most of it) barely escapes, so a follow-on ...

The Earth and Moon system we see today was formed when Theia, an ancient planet about the size of ... Most theories claim the ...

There's been some new research about an ancient planet - called Theia - that experts think helped form the Earth we know today. Scientists think that Theia crashed into Earth billions of years ago ...