The near-Earth enhancement of asteroidal over cometary dust.

摘要: The study deals with a theory suggesting cometary origin for most of the stratospheric cosmic dust. It is argued, though, that dust, as well dust sampled by earth-orbiting collectors, not representative true composition zodiacal cloud. A substantial near-earth collection bias enhances low-velocity component in and collectors. This arises from gravitational focusing, which substantially biases all micrometeorite collections favor interplanetary atmospheric entry heating, further noted that, addition to these two effects, increasing collision probability between particle nongravitating planet will farther lower geocentric velocity at opportunity.