planetesimal

American  

[plan-i-tes-uh-muhl] / ˌplæn ɪˈtɛs ə məl /

noun

1. one of the small celestial bodies that, according to one theory planetesimal hypothesis, were fused together to form the planets of the solar system.

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adjective

1. of or relating to a planetesimal or planetesimals.

planetesimal Scientific  

/ plăn′ĭ-tĕs′ə-məl /

1. Any of innumerable small bodies of accreted gas and dust thought to have orbited the Sun during the formation of the planets.

2. ◆ 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.

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Etymology

Origin of planetesimal

First recorded in 1900–05; planet + (infinit)esimal

Example Sentences

"If the mounds are indeed representative of the building blocks of ancient planetesimals like Arrokoth, then planetesimal formation models will need to explain the preferred size for these building blocks."

From Science Daily • Oct. 3, 2023

"In this model, 'Oumuamua began as an icy planetesimal that was irradiated at low temperatures by cosmic rays during its interstellar journey, and experienced warming during its passage through the Solar System."

From Salon • Mar. 26, 2023

“This provides further support that Oumuamua originated as a planetesimal relic broadly similar to solar system comets.”

From New York Times • Mar. 22, 2023

“Now more and more people are talking about a planetesimal source,” says Myriam Telus, a planetary scientist from the University of California, Santa Cruz.

From Scientific American • Dec. 8, 2020

The point is not necessarily in opposition to the planetesimal hypothesis; but whatever the explanation, it ought to apply to the planet as well as to the Sun.

From Popular Science Monthly Oct, Nov, Dec, 1915 — Volume 86 by Anonymous