Extraterrestrial magnetic spherules: their association with meteor showers and rainfall frequency

Abstract

The relationship between meteoric activity and extraterrestrial particle concentration in the troposphere is examined experimentally using magnetic spherules as an indicator of the larger flux. Spherules were collected by high volume air fiitration at 0.5°S, 19.5, 40, 47.5 and 65°N latitudes from August through October 1967; the simultaneous occurrence of concentration peaks at all stations precludes the likelihood of a terrestrial origin of these particles. The sizes and densities of spherules were used to calculate probable falling times and thus to identify parent meteor streams. Various influences altering theoretical falling times were evaluated to establish limits of validity for the calculations. The chemical analyses suggest that meteor streams vary in the amounts of stony and iron fragments they introduce into the atmosphere, or may consist wholly of one or the other. Concentration peaks of 7–8 μ, dia. spherules were found on days preceding periods of rainfall frequency anomalies. Frequency of rainfall and periods of maximum meteor shower activity correlate over a 52-yr period where synoptic conditions favor rain initiation through particle flux into high cirrus levels. The study concludes that the experimental evidence, together with proposed revisions in the Bowen hypothesis, restore credibility to the concept of meteoric influences on rainfall.