planetesimal
Americannoun
adjective
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Any of innumerable small bodies of accreted gas and dust thought to have orbited the Sun during the formation of the planets.
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◆ 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.
Etymology
Origin of planetesimal
First recorded in 1900–05; planet + (infinit)esimal
Vocabulary lists containing planetesimal
Earth and the Solar System - Middle School
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Space Science (Astronomy) - Middle School
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Space Science (Astronomy) - High School
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Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
The SwRI study suggests that these "building blocks" could guide further work on planetesimal formational models.
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
“I’m confident in this being a major advance in our understanding of planetesimal formation, but someone will probably ask, ‘Well, this is just one object.
From Scientific American • Feb. 20, 2020
According to both the nebular and the planetesimal hypotheses, the earth's crust appears to be colder now than it was hundreds or thousands of millions of years ago.
From Climatic Changes Their Nature and Causes by Huntington, Ellsworth
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
