“You can be the Moon and still be jealous of the stars.” -Gary Allen
Earlier this week, NASA announced the discovery of Asteroid 2016 HO3, calling it Earth’s second moon. And it turns out that this is an object in a stable orbit, the same distance from the Sun as the Earth, that can be found revolving around our world at a distance between 38 and 100 times the distance from us to the Moon.
But that isn’t exactly the same as having a second Moon! In order to be considered not just a natural satellite but a stable one, you need to remain orbiting your parent world for a long period of time, not just tens, hundreds or thousands of years, like a transient quasi-satellite. Despite its current orbital characteristics, this object is much more akin to the multiple Trojan asteroids orbiting with our world than anything we’d consider moon-like.