On the influx of small comets into the Earth's upper atmosphere II. Interpretation

Large, transient decreases of atmospheric dayglow intensities at ultraviolet wavelengths, primarily the atomic oxygen emissions at 130.4 nm, are interpreted in terms of an influx of heretofore undetected comet‐like objects. The primary composition of these comet‐like objects is water snow or clathrate in the form of a fluffy aggregate. These small comets are covered with a dust mantle and the tensile stress at fracture is estimated to be ∼ 0.1 dyne/cm². The water molecules that form the absorbing blanket for ultraviolet emissions arrive at the top of the earth's atmosphere as a piston of gas with bulk speed ≲ 20 km/sec. The mass of each of these comet‐like objects is ∼ 108 gm, or ∼ 100 tons. The global influx rate is ∼ 20 comets per minute. The global mass accretion rate by the earth's atmosphere is ∼ 1012 kg/year, and sufficient to replace the atmospheric mass in ∼ 5 × 106 years. The earth and the other bodies in the solar system would be thus more strongly coupled to cometary matter than presently thought.