Steve wrote: > Does anyone have the actual rate of fall already calculated? Is the fall > time a universal law of physics learned by all meteoritic students in > "Strewnfields 101" class?
I have some indicative data for you from the Dutch Glanerbrug fall. This hit a house and shattered, and Peter Jenniskens was able to determine from the fragment size distribution that the velocity upon impact was of order 30-120 meter/s (see P. Jenniskens et al., Pub. Astr. Inst. Czech. no. 79 (1992), 1-18). If we take that as a typical value, it would take some 2.5 minutes to come down from 15 km altitude. Casper ter Kuile made a model calculation of the free fall of Glanerbrug which does take in account atmospheric drag on the falling meteorite. For an object (assumed spherical) of about 1 kg falling in free fall from 25 km altitude, this indeed provides impact velocities of order 50-110 meter/s, and a fall duration of some 3 minutes. (see Radiant (J. Dutch Meteor Soc.) 12 (1990), 78-80). So yes: the actual impact of a meteorite will occur a few minutes after the fireball in a typical case. - Marco ---------- Marco Langbroek [EMAIL PROTECTED] [EMAIL PROTECTED] http://home.wanadoo.nl/marco.langbroek "What seest thou else In the dark backward and abysm of time?" William Shakespeare The Tempest act I scene 2 ---------- ______________________________________________ Meteorite-list mailing list [EMAIL PROTECTED] http://www.pairlist.net/mailman/listinfo/meteorite-list
