Cosmic dust – also called extraterrestrial dust, space dust, or star dust – is dust that occurs in outer space or has fallen onto Earth. Most cosmic dust particles measure between a few molecules and 0.1 mm (100 μm), such as micrometeoroids. Larger particles are called meteoroids. Cosmic dust can be further distinguished by its astronomical location: intergalactic dust, interstellar dust, interplanetary dust, and circumplanetary dust. There are several methods to obtain space dust measurement.
Porous chondrite dust particle
Artist's impression of dust formation around a supernova explosion.
Zodiacal light caused by cosmic dust.
Cosmic dust of the Andromeda Galaxy as revealed in infrared light by the Spitzer Space Telescope.
Dust is made of fine particles of solid matter. On Earth, it generally consists of particles in the atmosphere that come from various sources such as soil lifted by wind, volcanic eruptions, and pollution. Dust in homes is composed of about 20–50% dead skin cells. The rest, and in offices and other built environments, is composed of small amounts of plant pollen, human hairs, animal fur, textile fibers, paper fibers, minerals from outdoor soil, burnt meteorite particles, and many other materials which may be found in the local environment.
A dust storm blankets Texas houses, April 1935
Three years of use without cleaning has caused this laptop heat sink to become clogged with dust, and it can no longer be used as it may catch fire.
Domestic dust on a finger
Large dust storm over Libya