how many moons does the earth have?

The earth has one main moon plus six others.
   It is certain that Luna (as astronomers call the moon) is the only celestial body to follow a strict orbit of the earth, but currently there are six other 'Near Earth Asteroids' which do follow the Earth around the sun, though cannot be spotted with the naked eye.
   Also called 'co-orbitals', the first of these to be discovered was Cruithne (Cru-een-ya), a three mile wide satellite. it was discovered in 1997 and named after Britain's earliest recorded Celtic tribe. It has a horseshoe shaped orbit.
   Since then, six more have been identified; The 2000 PH5, 2000 WN10, 2002 AA29, 2003 YN107 and the 2004GU9.
   Many astronomers would argue that these aren't moons, but are cetainly more than just the average asteroid. They also take about one year to orbit the sun (it's like two  runners running around a track in different lanes and at the same speed) and every now and then they would come close enough to exert a very slight gravitational influence.
   So whether it be quasi satellites, pseudo-moons or companion asteriods (as scientists have it), they are worth monitoring; maybe some, or even all of them would one day achieve a more regular orbital pattern.