planetesimal (redirected from Planetessimal)

plan·e·tes·i·mal  (pln-ts-ml)

n.

Any of innumerable small bodies thought to have orbited the sun during the formation of the planets.

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[planet + (infinit)esimal.]

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plane·tesi·mal adj.

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planetesimal  (pln-ts-ml)

Any of innumerable small bodies of accreted gas and dust thought to have orbited the Sun during the formation of the planets. The theory that explains the formation of the solar system in terms of the aggregation of such bodies is known as the planetesimal hypothesis. According to this theory, first proposed in 1900, the planetesimals formed within a spiral disk of dust and gas surrounding a central nucleus. Their gravitational attraction eventually caused the planetesimals to coalesce into protoplanetary disks from which larger objects such as planets, asteroids, and satellites were formed, while the nucleus coalesced into the Sun.

Thesaurus

Noun

1.

planetesimal - one of many small solid celestial bodies thought to have existed at an early stage in the development of the solar system celestial body, heavenly body - natural objects visible in the sky