The moon is weird. It's completely unlike anything else in the solar system. So how did our planet end up with such a special moon? The answer is that, surprisingly enough, the moon is a piece of our planet.
There's a lot going on with the moon. For starters, it exists, which is weird in its own way. Mercury has no moons, and neither does Venus. Mars does have two moons, but they're really just captured asteroids. Earth is the only rocky planet in the solar system with a significant moon.
