ABSTRACT
Meteors were once regarded as atmospheric phenomena. The status of meteors was solved in 1798 by two German students, H. W. Brandes and J. F. Benzenberg, of the University of Gottingen. The total number of meteors entering the atmosphere daily has been given as 75 000 000 for meteors of magnitude 5 or brighter. Meteors of magnitude -5 or brighter–that is to say, appreciably more brilliant than Venus–are conventionally termed fireballs. A meteor may enter the atmosphere at a velocity anywhere between 11 km s-1 and 72 km s-1; it will be violently heated as it enters the upper atmosphere at an altitude of 150 km above the ground. On the night of 12–13 November 1833 there was a brilliant meteor shower; the meteors came from the constellation of Leo. Comet Tempel-Tuttle returned to perihelion in 1998, and was expected to produce another meteor storm.
