Dust from orbit

Abstract

The number of large dust particles in the stratosphere increased more than ten times from 1981–84, according to a study reported in the January 20 Journal of Geophysical Research. The likely source for most of the particles, say the authors, is the growing junkyard of space debris in low orbit around Earth.The article contains analyses of particles collected in 1976, 1981, and 1984 on surfaces coated with sticky silicone oil and mounted underneath the wings of National Aeronautics and Space Administration planes flying through the stratosphere at 17–19 km altitude. Only particles one μm in diameter or larger stuck to the collectors. That is smaller than most liquid and solid aerosols, which act as condensation nucleii for clouds and change the radiative energy balance of the troposphere.