There May Be Dozens of 'Mini Moons' Zipping Around the Earth

By Maddie Stone on at

While Earth’s official Moon is busy photobombing us, a bunch of smaller upstarts are vying to become Moon #2. That’s right: Earth may have a rotating entourage of ‘mini moons’, and astronomers are determined to find them.

“Only one is known,” Robert Jedicke said at a meeting of the International Astronomical Union, according to Science News. “It’s not fictional.”

The ‘one mini moon’ Jedicke is referring to is roughly three metres in size. It was discovered in 2006 and orbited the Earth for about a year before escaping our planet’s gravity. Three metres may not sound big enough to warrant any sort of moon status (after all, we’ve got hunks of orbiting space trash that aren’t much smaller) but I’m not at liberty to make such weighty decisions, now, am I?

According to the mini moon fan club, three metres is actually pretty big. Says Science News:

Typically no larger than a washing machine, mini moons are temporarily caught by Earth’s gravity. Beach ball-sized mini moons buzz around Earth by the dozen, like a swarm of interplanetary gnats, while dump truck-sized asteroids swing by once every 50 years or so.

These moon wannabes are so small it’s going to take a lot of telescope time for astronomers to spot them. Jedicke’s hopeful he’ll turn a few up next year, using the Subaru Telescope in Hawaii. Very large telescopes expected to come online within the next decade could also aid in the search.

Besides having a cute name, why do these Earth-orbiting mosquitos matter? They could make good targets to pilot-test asteroid mining equipment, for one. Or any other sort of small landers and/or space probes humans dream up. The sky’s the limit — or rather, the edge of Earth’s gravitational field is. [Science News]

Top image : Path of a simulated mini moon temporarily captured by the Earth, via K. Teramura / UH IFA