Categories: world

The Story of Dust, Through Space and Time

What is dust? It feels ridiculous just asking that question sitting in India. Dust is everywhere. On the roads, in your nose, in your lungs. You lock up your house, go on a month-long holiday and come back, and there's a nice patina on the table. It's inside your laptop, driving the cooling fan nuts. It's also in the atmosphere, in orbit around Earth, in outer space even. It makes up nightmarish storms on Mars. Philip Pullman and Steven Erikson have written books fantasizing about it. Dust is omnipresent. Earth The Saharan dust plume in June 2018. Credit: NASA / Earth Observatory Dust is fine particulate matter. It originates from a tremendous variety of sources. The atmospheric – or aeolian – dust we are so familiar with is composed of small particles sheared off of solid objects. For example, fast-blowing winds carry particles away from loose, dry soil into the air, giving rise to what is called fugitive dust. Another source is the smoke from exhaust pipes. Yet another is myths of the family Pyroglyphidae. They eat flakes of skin, including those shed by humans, and digest them with enzymes that stay on in their poop. In your house, exposure to their poop can trigger asthma attacks. Winds lift particulate matter off Earth's surface and transport them into the troposphere. Once dust gets up there, it acts like an aerosol, trapping heat below it and causing Earth's surface to warm. Once it collects in sufficient quantities, it begins to affect…

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