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Dust is a general name for minute solid particles with diameters less than 500 micrometers. 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 enough of the minute particles are dispersed within the air in a given area (such as flour or coal dust), under certain circumstances can be an explosion hazard.

Coal dust is responsible for the lung disease known as Pneumoconiosis, including black lung disease, which occurs among coal miners. This danger has resulted in a number of laws regulating environmental standards for working conditions.

House dust

File:Dust.jpg

A sample of house dust and hair

Dust in homes, offices, and other human environments is mainly generated by the inhabitants (especially domesticated pets such as dogs, cats and birds), and mainly from their skin cells that slough off. ^{[citation needed]} Some atmospheric dust from the outdoors is also present. On average, approximately 6 mg/m²/day^[1] of house dust is formed in private households, depending primarily on the amount of time spent at home. "Dust bunnies" are little clumps of fluff that form when sufficient dust accumulates.

Insects and other small fauna found in houses have their own subtle interactions with dust that may have adverse impact on the health of its regular occupants. Thus, in many climates it is wise to keep a modicum of airflow going through a house, by keeping doors and windows open or at least slightly ajar. In colder climates, it is essential to manage dust and airflow, since the climate encourages occupants to seal even the smallest air gaps, and thus eliminate any possibility of fresh air entering.

House dust mites are on all surfaces and even suspended in air. Dust mites feed on minute particles of organic matter, the main constituent of house dust. They excrete enzymes to digest dust particles; these enzymes and their feces, in turn, become part of house dust and can provoke allergic reactions in humans. Dust mites flourish in the fibers of bedding, furniture, and carpets.

The particles that make up house dust can easily become airborne, so care must be exercised when removing dust, as the activity intended to sanitize or remove dust may make it airborne. One way to repel dust is with some kind of electrical charge, but house dust can be removed by as many as 10 methods, such as: wiping, swiping, or sweeping by hand, or with a dust cloth, sponge, duster, or broom, or by suction by a vacuum cleaner or air filter. The device being used traps the dust; however, some may become airborne and come to settle in the cleaner's lungs, thus making the activity somewhat hazardous.

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 nebulae and reflection nebulae.

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 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.

Dust in fiction

In JM Barrie's children's novel Peter Pan (1911), "pixie dust" is a substance used to help create magical effects.
In Clark Ashton Smith's short horror story "The Treader In The Dust" (1935) [1], a scholar unwittingly calls forth a demon that personifies dustiness.
In the Peanuts comic strip, the character Pig-Pen (1954) is constantly surrounded by a cloud of dust.
In Arthur C. Clarke's A Fall of Moondust (1961), 21st century tourists "cruise" across the Moon's "Seas" that have filled over eons with very fine dust, which is so fine that it almost behaves like water.
In Hal Clement's short science fiction story "Dust Rag" (1965), two astronauts struggle with dust that stuck to their helmets, blinding them.
In Philip Pullman's best-selling series His Dark Materials (1995), 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 (2003), Fat Fighters group leader Marjorie Dawes distinctively instructs the dieters to eat dust as it is "low in fat."
In "The Dust Has Landed", an episode Graham Duff's science-fiction radio comedy Nebulous, sentient dust declares war against humanity, forcing the reinvention of the vacuum cleaner.

Dust in religion

In ancient Sumerian mythology:

The afterlife consists of the dreary "House of Dust and Darkness".

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.

In Genesis 13:16, God states to Abram (later Abraham):

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.

Note however that in both of these Biblical passages, the Hebrew word is עפר (`âfâr), which can also mean earth or dirt.

Sources

^ House dust formation rate (in German)

Reference

Holmes, Hannah; (2001)The Secret Life of Dust. Wiley. ISBN 0-471-37743-0

External links

[1] House dust formation rate (in German)

[1]

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 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 (spacecraft)|Stardust]], which flew past [[Comet Wild 2]] in [[2004]] and returned a capsule of the remains of the comet to the U.S. in January 2006. The [[Japan]]ese [[Hayabusa]] spacecraft is currently on a mission to collect samples of dust from the surface of an [[asteroid]].
-In outer space there are little creatures called dust mites which eat away at the earths crust this does not harm us in any way shape or form. They help our society to grow aliens and become richer and famous around the world. Many scientists believe that the chemicals that dust mites carry are lethal but that's utter nonsence, scientists are nothing but a bunch of lazy fat people who spend their time laying around looking into a microscope searching for answers that are clearly not going to be found for another 500 years or so. An example is how to make chocolate laying bunnies geez has anyone ever heard of a myth before-legends that arn'n neccisarily true. It makes you think about how much money we donate just for them to do that. Its appalling (I can't spell). Thank you very much mum and dad for not letting me go on msn now look what i'm doing wasting my time writing nonsense paragraphs in a completely different section of wikipedia. It's pointless but still better than doing assignments.
 ==Dust in fiction==
 *In [[James Matthew Barrie|JM Barrie]]'s children's novel ''[[Peter Pan]]'' ([[1911]]), "[[pixie dust]]" is a substance used to help create magical effects.