Earth Once Had Two Moons?

Scientists are suggesting this morning that a tiny second moon may have once orbited the Earth before colliding with the other Moon, which could be the explanation of why the two sides of the Moon are so radically different.

Science.com speculates that the remains of the smaller moon could make up the highlands now on the Moon's "far side".

The second smaller moon would have been about 750 miles wide, and could have resulted from the same "collision" that created our current Moon.

(From Science.com)