2004 FH

2004 FH is an asteroid about 30 meters in diameter. It was discovered on 16 March 2004 by the LINEAR sky monitoring in New Mexico, USA. It moves at a distance of 0.581 ( perihelion ) to 1.054 ( aphelion ) astronomical units in 270 days and 5 hours around the sun, the orbital eccentricity is thus 0.289. Its orbit is almost inclined at 0.021 ° to the ecliptic. 2004 FH rotates fairly quickly once in about 3 minutes on its axis.

2004 FH passed by the Earth on 18 March 2004 at 22.08 UTC clock at a distance of only about 43,000 km ( measured from the surface ) at 7.9 km / s relative velocity. From the center of the earth from measured equivalent to 0.00035 AE or about four Earth radii. Of all the currently known near-Earth objects ( NEO ), only the even smaller 2004 FU162 the earth is far closer.

A collision with Earth could have possibly led to strong regional devastation. One of the explanatory hypotheses of the Tunguska event is, for example, from a 50 m large body collided with the Earth, which would be comparable to 2004 FH. The fact that objects of this size happen in such close quarters the earth approximately every two years is expected, however, 2004 FH is the first one that was actually observed.

At the time of closest approach the object was with an apparent magnitude of about 10 mag but too dark to perceive it with the naked eye.

With a telescope in 2004 FH was virtually unobservable from Germany. In the south, it was about 3 degrees above the horizon in the southern sky in the constellation air pump. In the north of Germany in 2004 FH was below the horizon. In the following nights, the object was further in the northern sky, but was again much weaker due to the increased distance.

Due to the small distance, there was a large parallax of in Germany about 5 degrees, depending on the geographic location, and thus deviations from the geocentric positions given in the ephemeris. 2004 FH moved with a maximum of 33 seconds of arc per second of time across the sky.