Meteoritic time-of-fall patterns

Abstract

The yearly and monthly time-of-fall patterns for all meteorite falls and for certain types of meteorites were examined for departures from randomness. The histogram of falls per decade contains at least three peaks and a sharp decrease after 1940 which is believed to reflect a decrease in the rate of influx of meteorites. The yearly fall pattern of the calcium-rich achondrites parallels the peaks in the falls per decade histogram very closely. The only monthly fall pattern which appears to depart greatly from randomness is that for the veined-olivine-hypersthene chondrites.