7:49 PM
Astronomy Pirate
Dust, it's everywhere! From the Earth-based perspective, dust is that layer of film made up of dirt, mostly biological, that settles on things in the corners of your room, or floating in the air reflecting light. On a cosmological scale, dust is made up of a huge variety of materials, literally just about everything in the Universe. And once cosmic dust settles, it forms stars and galaxies.
Cosmic dust also has a pretty large range in size, from just a few molecules up to a couple microns (µm). There really is no upper limit, but after a certain point, things obviously start to become asteroids and comets and meteoroids and such. There is a proposed definition for a meteoroid of being between 100 µm and 10 m across. That would then classify dust any smaller then 100 µm, and starting on a molecular level. Human hair is usually around 100 µm thick.
Cosmic dust can further be distinguished by it's location.
Cosmic dust also has a pretty large range in size, from just a few molecules up to a couple microns (µm). There really is no upper limit, but after a certain point, things obviously start to become asteroids and comets and meteoroids and such. There is a proposed definition for a meteoroid of being between 100 µm and 10 m across. That would then classify dust any smaller then 100 µm, and starting on a molecular level. Human hair is usually around 100 µm thick.
Cosmic dust can further be distinguished by it's location.
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