How many moons does the earth have?

zmizet:

At least 7.

The moon we often see, called Luna by astronomers, is the only celestial body to observe a strict orbit of the earth. But there are now six other “Near-Earth” asteroids (NEAs) that do follow the earth around the sun, despite being invisible to the naked eye.

The first one identified was Cruithne (Cru-een-ya, named after Britain’s earliest recorded Celtic tribe) and it is a three-mile-wide satellite, discovered in 1997. It has a horseshoe-shaped obrit.

Six more have been named since then: 2000 PH 5’, 2000 WN 10’. 2002 AA 29’, 2003 YN 107’, and 2004 GU 9’.

Many astronomers argue that these are not really moons. But they are worth keeping an eye on since one day some or all of them may settle down into a regular orbital pattern.

- The Book of General Ignorance