The population of small (1–300 μ‎m) particles of cometary and asteroidal origin lying roughly in the ecliptic plane out to about 5 au from the Sun; measurements from the Pioneer and Voyager probes have indicated much lower dust concentrations beyond the orbit of Jupiter. The distribution of the zodiacal dust is controlled mainly by Jupiter’s gravitational influence. Reflection of sunlight from the zodiacal dust gives rise to the gegenschein and zodiacal light. The total mass of zodiacal dust is estimated to be similar to that of an average comet nucleus.