A faint cone of light extending upward from the horizon in the direction of the ecliptic (zodiac). It is seen from tropical latitudes for a few hours after sunset or before sunrise.
The spectrum of the zodiacal light is similar to that of sunlight, so it has been suggested that it is due to the scattering of sunlight by extraterrestrial dust particles, which is believed to have been created during asteroid collisions and from the breaking up of comets. Some scattering is also due to electrons.
See also: Light.