Dust
From Wikipedia, the free encyclopedia
- For other uses, see Dust (disambiguation).
Image:Laptop dust.jpg Dust is a general name for minute solid particles with diameters less than 500 micrometers (otherwise, see sand or granulates) and, more generally, for finely divided matter. On Earth dust occurs in the atmosphere from various sources: soil dust lifted up by wind, volcanic eruptions, and pollution are some examples. Airborne dust is considered an aerosol and can have a strong local radiative forcing on the atmosphere and significant effects on climate. In addition, if composed of a flammable substance (such as flour or coal dust), under some circumstances it can be an explosion hazard.
Dust is responsible for the lung disease known as Pneumoconiosis, including black lung disease that occurs among coal miners. These dangers have resulted in a number of laws regulating environmental standards for working conditions.
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[edit] Dust in outer space
Cosmic dust is widely present in space, where gas and dust clouds are primary precursors for planetary systems. The zodiacal light, seen in the sky on a dark night, is produced by sunlight reflected from particles of dust in orbit around the Sun. The tails of comets are produced by emissions of dust and ionized gas from the body of the comet. Dust also covers solid planetary bodies, and vast dust storms can occur on Mars that can cover almost the entire planet. Interstellar dust is found between the stars, and high concentrations can produce diffuse nebula and reflection nebula.
Dust samples returned from outer space could provide information about conditions in the early solar system. Several spacecraft have been launched in an attempt to gather samples of dust and other materials. Among these was Stardust, which flew past the comet Wild 2 in 2004 and returned a capsule of the remains of the comet to the U.S. in January 2006. The Japanese Hayabusa spacecraft is currently on a mission to collect samples of dust from the surface of an asteroid.
[edit] Dust in fiction
- In Philip Pullman's bestselling series His Dark Materials, dust (or "Dust", as it is spelled in the books) plays an important part by creating a connection between different worlds.
- In the TV comedy Little Britain, Fat Fighters group leader Marjorie Dawes distinctively instructs the dieters to eat dust as it is "low in fat".
- In JM Barrie's children's novel Peter Pan, "pixie dust" is a substance used to help create magical effects.
- In Clark Ashton Smith's short horror story "The Treader In The Dust" [1], a scholar unwittingly calls forth a demon which personifies dustiness.
- In Hal Clement's short science fiction story "Dust Rag", two astronauts struggle with dust that stuck to their helmets, blinding them.
[edit] Dust in religion
In the Bible:
- In Genesis 3:19, God—following The Fall, Adam and Eve's transgression—states to the couple (representing humanity):
- By the sweat of your brow you will eat your food until you return to the ground, since from it you were taken; for dust you are and to dust you will return. [Emphasis added]
This latter clause is used in the Ash Wednesday service in some churches for the administering of ashes.
- I will make your offspring like the dust of the earth, so that if anyone could count the dust, then your offspring could be counted.
[edit] See also
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[edit] Reference
- Holmes, Hannah; (2001)The Secret Life of Dust. Wiley. ISBN 0-471-37743-0
[edit] Sources
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