We may only have one capital-M Moon, which affects our tides and causes our hearts to swell with love on summer nights, but we have a lot of rocks orbiting us. Find out about the many moons we pay no attention to.
The Earth almost never has only one cold space rock orbiting it. According to researchers at the University of Helsinki, the University of Hawaii, and the Paris Observatory, we are inundated with tiny temporary mini-moons at almost every point during our orbit. These were ignored until now, mostly because it was hard to spot them, some of them being only about a few feet wide. Once people did start spotting the wee little shiners, they began to wonder how many were out there at any one time.
These are, as stated before, temporary moons. We might be all the more proud of them for that, knowing that the Earth's gravity steals them away from their orbits around the sun for a space of a year or so. But in the end, they always go back. The problem of figuring out how many, if any, there were at any one time became gauging how many objects the Earth drew in, versus how short their stay would be.
The researchers garnered a supercomputer and tried to figure out exactly how asteroids move past Earth. They calculated the path of ten million virtual asteroids, trying to see which ones ventured close. They paid special attention to the 18,000 of these simulated asteroids that were drawn in by Earth's gravity. The mini moons would not orbit peacefully. They twisted around Earth in complicated paths before zooming off. At last the researchers came to the conclusion that, at any point in time, there is at least one other moon in the sky. This includes only moons with the diameter of one meter or larger. Smaller objects could be orbiting as well.
Our most famous mini-moon was 2006 RH120, a lump of rock the size of a car that twisted around the Earth in 2006. Perhaps whatever is orbiting out there now, is larger. It won't be there for long, though. Anyone who sat through high school English remembers Juliet telling Romeo, when he swears his love for her, "Swear not by the moon! The inconstant moon!" She was righter than she knew.
Top Image: NASA
2006 RH120 Image: NASA