2004 FH is a near-Earth asteroid that was discovered on March 15, 2004 by the NASA-funded LINEAR asteroid survey. The object is roughly 30 metres in diameter and passed just 43,000 km above the Earth's surface on March 18, 2004 at 22:08 UTC; making it the closest approach to Earth ever recorded at the time (see the diagram below). For comparison, geostationary satellites orbit Earth at 35,790 km.

2004 FH is an Aten family asteroid, although by some definitions it should be called a meteoroid, since it is smaller than 50 metres in diameter. 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 ground level effect. Despite its relatively small size (about 30 metres), it is still the third largest asteroid detected coming closer to the Earth than the Moon.

The asteroid will not make another close approach to Earth until 2044 when it will be no closer than 1.4 Gm (1.4 million kilometres). 2004 FH also has the distinction of having the lowest inclination of any known near-earth asteroids.

References

1. Chesley, Steven R; Chodas, Paul W. Recently Discovered Near-Earth Asteroid Makes Record-breaking Approach to Earth (http://neo.jpl.nasa.gov/news/news142.html). Pasadena, California (USA): NASA Near Earth Object Program Office. March 17, 2004.

Related topics

• Near-Earth object
• List of noteworthy asteroids
• Wikipedia Project: Astronomical Objects

External links

• MPEC 2004-F24 (http://cfa-www.harvard.edu/mpec/K04/K04F24.html)
• Images of 2004 FH (http://klenot.klet.org/2004fh.html)
• Official press release by NASA (http://neo.jpl.nasa.gov/news/news142.html)
• Asteroid Scare Prompts NASA to Formalize Response by Robert Roy Britt (http://www.space.com/scienceastronomy/asteroid_warning_040322.html)
• Minor Planet Center: Closest Approaches to the Earth by Minor Planets (http://cfa-www.harvard.edu/cfa/ps/lists/Closest.html)