The gegenschein and distribution of interplanetary dust

Investigations to determine the source of the gegenschein indicated: (1) The gegenschein is an effect, not a thing, and is due to an increase in the reflectivity, near opposition, of dust particles in heliocentric orbits, and is not due to an accumulation of material near the earth. (2) The density of the reflecting particles increases outside the earth's orbit; therefore, it can be explained by dust produced by collisions between asteroids. A cometary origin for the material is considered unlikely.