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

Objects of this scale are known as planetesimals, similar in size to many asteroids and comets in our solar system, but far smaller than dwarf planets such as Pluto.

From Science Daily

Instead, both appear to be debris clouds created when large planetesimals crashed into each other.

From Science Daily

During the long process in which tiny grains grew into planets, intermediate objects known as planetesimals formed.

From Science Daily

Instead, these particles accumulated in dense bands, allowing them to merge into planetesimals, the solid precursors of planets.

From Science Daily

Over time, these planetesimals collide and stick together, eventually forming planets.

From Science Daily