Theia (planet)

Theia is a name given to a long-ago planet that scientists think smashed into the Earth back in ancient history. This crash created a giant cloud of dust and pieces of the planet, and these pieces became the moon that circles the Earth today. Scientists think Theia was probably a rocky planet about the same size as Earth or maybe even a little bigger. We may never know exactly what Theia looked like because it was destroyed a long, long time ago.