A collision with a Mars-size planetary object called Theia 4.44 billion years ago, left, might not only have formed the moon but also given rise to plate tectonics.

GPS measurements of plate motion aren’t enough to figure out the forces involved, just as the speed of two cars isn’t really enough to predict the outcome of a collision.

The plate tectonics that determine the shape of our continents may have originated from a huge impact billions of years ago. This huge collision with the Earth, thought to have occurred around 4.5 ...

Plate-tectonics study could explain why some mountains are higher than expected. Nicola Jones ... But this collision has only been going on for less than 10 million years.

THE WOODLANDS, TEXAS — Vestiges of a moon-forming cataclysm could have kick-started plate tectonics on Earth.. The leading explanation for the origin of the moon proposes that a Mars-sized ...

Click here to see a Shockwave animation ... For at least 80 million years the oceanic Indian Plate continued its inexorable collision ... Because Nepal's boundaries are marks on the ...