Chapter 29 - Dust in the Solar System

Abstract

Solar system dust is finely divided particulate matter that exists between the planets. These cosmic dust particles are also often called micrometeoroids and range in size from assemblages of a few molecules to tenth-millimeter-sized grains, above which size they are called meteoroids. Sources of this dust are larger meteoroids, comets, asteroids, the planets, and their moons and rings; there is interstellar dust sweeping through the solar system. Because of their small sizes, forces additional to solar and planetary gravity affect their trajectories. Radiation pressure and the interactions with ubiquitous magnetic fields disperse dust particles in space away from their sources. In this way, micrometeoroids become messengers of their parent bodies in distant regions of the solar system. A tablespoon of finely dispersed micrometer-sized dust grains scatters about 10 million times more light than a single meteoroid of the same mass. Therefore, a tiny amount of dust becomes recognizable, while the parent body from which it derived may remain undetected.