The Composition of Dust: Of Mites and Mars

When the cleaners are finished, you’ll be able to breathe easier. Increase your satisfaction with a look at one thing they’ve banished: dust.

Whether you're resting in a mountain cabin, traveling through a city, or being vented out an airlock into outer space, dust is all around you. Microscopic particles—usually a combination of soil, pollen, skin cells, and minerals—can pile up quickly indoors. The problem is exacerbated by tiny creatures called dust mites, which gather in groups of up to 500 per gram of dust to devour flakes of human skin while multiplying in number, excreting waste, and probably chittering away. No matter where you are on Earth, a mote of dust is presently traveling straight toward your eye, thanks to the persistent creation of dust in almost any climate humans inhabit.

Even beyond our planet, dust is ubiquitous: astronomers face the universe's untidiness every time they peer through a telescope and find formations of cosmic dust, which absorb the visible light around them. Although it comes from exploding stars rather than flaky humans, space dust isn't so different from the domestic variety: a 2007 paper published in IEEE Transactions on Plasma Science explored the similarities between the formation of dust bunnies under beds and the coagulation of space dust into planets.