Interplanetary Dust Cloud

The interplanetary dust cloud is cosmic dust (small particles floating in space) which pervades the space between planets in the Solar System and in other planetary systems. It has been studied for many years in order to understand its nature, origin, and relationship to larger bodies.

In our solar system, the interplanetary dust particles not only scatter solar light (called the "zodiacal light", which is confined to the ecliptic plane), but also produce thermal emission, which is the most prominent feature of the night-sky light in the 5-50 micrometer wavelength domain (Levasseur-Regourd, A.C. 1996). The grains characterizing the infrared emission near the earth's orbit have typical sizes of 10-100 micrometers (Backman, D., 1997). The total mass of the interplanetary dust cloud is about the mass of an asteroid of radius 15 km (with density of about 2.5 g/cm3).