2004 FH is an Aten asteroid. It passed 43,000 km from the Earth on 18 March 2004. For comparison, geostationary satellites orbit Earth at 35,790 kilometers. Despite its small size, it is still the fourth largest asteroid detected coming closer to the Earth than the Moon.
Had this object hit Earth, it would probably have detonated high in the atmosphere. It might have produced a blast measured in hundreds of kilotons of TNT, but may not have produced any effect on the ground. It could also have been an Earth-grazing fireball if it had been much closer but not close enough to impact.[citation needed]
On 17 March 2044 the asteroid will pass no closer than 0.0116 AU (1,740,000 km; 1,080,000 mi) from the Earth.[5]2004 FH also has the distinction of having the lowest inclination of any known near-Earth asteroids.
Two weeks later another asteroid approached even closer, 2004 FU162, which was smaller, and a few years later 2009 DD45, which was closer in size passed by at similar distance.
This makes this object a fast rotator, currently among the Top 100 known to exist. The photometric observations also revealed, that 2004 FH is a tumbler with a non-principal axis rotation.[3]
Diameter and albedo
has been estimated to measure approximately 30 meters (100 feet) in diameter.[4] The Collaborative Asteroid Lightcurve Link assumes a standard albedo for stony asteroids of 0.20 and calculates a diameter of 24 meters based on an absolute magnitude of 25.7.[3]
^Rankings depend on definitions of meteoroid and approach. The 2-10 m 1972 grazer was at 57 km, the 44 kg 1990 grazer was about 100 km, possible 2006 grazer size and altitude not available. See List of asteroid close approaches to Earth.
