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Sep. 25, 2021
Comet dust is cosmic dust of cometary origin. These are particles of solid matter separated from comets during their flight in outer space. Dust particles range in size from a few molecules to hundreds of microns.
In recent decades, technical possibilities have appeared to study the matter of comets and cometary dust. In 1986, several spacecraft (Vega-1, Vega-2 - USSR; Giotto - ESA, etc.) investigated Halley's comet. In 2004, NASA's Stardust spacecraft approached Comet Wild at a distance of 240 km, collecting samples of comet dust from its tail using a special collector. In 2014, the ESA lander Philae lander landed on the Churyumov-Gerasimenko comet to study its substance.
As a result of these studies, it was found that solid cometary matter and cometary dust are a mixture of crystalline and amorphous minerals from the silicate class. The most common of them are: forsterite (Mg2SiO4), enstatite (MgSiO3), olivine (Mg, Fe) 2 [SiO4]) and pyroxenes - a group of minerals of the subclass of chain silicates. Iron oxides and sulfides were found in insignificant quantities.
In general, the results of studies of comet matter and cometary dust in recent years turned out to be quite unexpected. So, among scientists there was a popular point of view, according to which comets were formed at the earliest stages of the formation of the solar system, since their bulk is located in its peripheral (cold) parts and are samples of primary matter, from which the planets and their satellites were subsequently formed. And, indeed, a significant part of the matter of comets consists of cold material, but such minerals as olivine and others could only form under conditions of high temperatures - over 1000 ° C.
These facts allow us to cautiously assume that comets, apparently, consist of a mixture of substances formed at very different temperatures, possibly throughout the entire space of the solar system and at different times.
Source: Moscow Planetarium.
ROSCOSMOS Press Release: https://www.roscosmos.ru/32705/
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Images, Text, Credits: ROSCOSMOS/Moscow Planetarium/Orbiter.ch Aerospace/Roland Berga.
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