Another Moon for Earth? Well, Not Really, but It Depends on Your Point of View.

The Earth has one satellite, right? That fact is so solid, we just call it the Moon with a capital M. But due to a trick of gravity and timing, there are other objects out in space that aren't really moons but do travel along with Earth through space. I guess "companions" would be a better name. One of them was just discovered recently by astronomers: the asteroid 2016 HO3. It's small, probably 40-100 meters in size, and let me be clear: It orbits the Sun, not the Earth, so I wouldn't call it a ...