Earth may have had two moons

In a paper published on Wednesday in Nature, scientists proposed that two moons were formed billions of years ago when a Mars-sized planet slammed into the Earth — our Moon and a tiny Trojan moon that inhabited what’s known as a Lagrange point 60 degrees in front of or behind the Moon. Eventually the Sun’s gravity caused both moons to collide, with the tiny moon fragmenting across the far side of our Moon. Source: Nature