Giant-impact hypothesis

But we do have some pretty good theories.

The most widely accepted one is known as the Giant Impact Theory.

The story goes that back when Earth was just a wee proto-planet, it collided with...

I ended up missing about 50% of the votes in the Iowa legislature this year.

She finally developed a theory that could explain everything.

Well, almost everything.

A more recent computer simulation suggests another version of giant impact theory.

Earth's moon formed within a few hours of the collision between Earth and Theia.