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For submicron-sized dust particles this force becomes significant and for particles < 0.1 microns it exceeds solar gravity and the radiation pressure force. For example, interstellar dust particles of ~0.3 microns in size that pass through the heliosphere are either focused or defocused with respect to the solar magnetic equator.
Cosmic dust – also called extraterrestrial dust, space dust, or star dust – is dust that occurs in outer space or has fallen onto Earth. [ 1 ] [ 2 ] Most cosmic dust particles measure between a few molecules and 0.1 mm (100 μm ), such as micrometeoroids (<30 μm) and meteoroids (>30 μm). [ 3 ]
This anisotropic emission causes the photons to carry away angular momentum from the dust grain. The Poynting–Robertson drag acts in the opposite direction to the dust grain's orbital motion, leading to a drop in the grain's angular momentum. While the dust grain thus spirals slowly into the star, its orbital speed increases continuously.
For this reason, dust models are often employed in cosmology as models of a toy universe, in which the dust particles are considered as highly idealized models of galaxies, clusters, or superclusters. In astrophysics, dust models have been employed as models of gravitational collapse. Dust solutions can also be used to model finite rotating ...
Crazes in polystyrene (PS). Crazing is a yielding mechanism in polymers characterized by the formation of a fine network of microvoids and fibrils. [1] [2] These structures (known as crazes) typically appear as linear features and frequently precede brittle fracture.
Mineral dust is mainly constituted of the oxides (SiO 2, Al 2 O 3, FeO, Fe 2 O 3, CaO, and others) and carbonates (CaCO 3, MgCO 3) that constitute the Earth's crust.The composition of mineral dust, usually named in atmospheric sciences as mineralogy composition, is relevant for different physical and chemical processes in the atmosphere, for example, oxides with iron have an effect in the ...
Atmospheric particulate matter, also known as particulate matter, or PM, describes solids and/or liquid particles suspended in a gas, most commonly the Earth's atmosphere. [1] Particles in the atmosphere can be divided into two types, depending on the way they are emitted. Primary particles, such as mineral dust, are emitted into the atmosphere ...
House dust under a microscope Domestic dust on a ribbon A video on reducing dust exposure in the workplace. Dust control is the suppression of solid particles with diameters less than 500 micrometers (i.e. half a millimeter). Dust poses a health risk to children, [13] older people, and those with respiratory diseases. House dust can become ...