Earth Has Two Moons, But It's Not What You Think
In a day packed with astronomy news, researchers at the University of Hawaii in Honolulu came out today and declared that earth probably has two moons at any one time. The news is obviously being greeted with amazement and bad jokes about Star Wars and whatnot, but don't worry, you didn't just miss one of those moons all this time. Researchers picked up on a small satellite orbiting the earth a few years ago and used it to model how other satellites interact with our gravitational pull. Technology Review quotes the researchers:
"At any given time, there should be at least one natural Earth satellite of 1-meter diameter orbiting the Earth," say Granvik and co. These objects should hang around for about 10 months and make about three revolutions of the planet. That means Earth ought to have a metre-sized moon right now.
Wait 1 meter? If Pluto isn't big enough to be planet, why does that get to be our second moon? At any rate, this supposed second moon of ours (if you can call it that!) is small. Still, Gizmodo says the implications for astronomers are big:
Once we detect [a satellite], we can send a few astronauts to analyze it instead of getting a full crew to a distant one ...The data about the formation of the solar system that we can obtain from these asteroids—without having to spend a lot of money—could be amazing.
It's not clear to us how feasible that plan sounds, but it does seem like there's no obviously down side (dark side?) to having two moons.
