planetesimal

[ plan-i-tes-uh-muhl ]

/ ˌplæn ɪˈtɛs ə məl /

Astronomy

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noun

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

adjective

of or relating to a planetesimal or planetesimals.

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Origin of planetesimal

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

Words nearby planetesimal

planetarian, planetarium, planetary, planetary nebula, planetary precession, planetesimal, planetesimal hypothesis, planet gear, planetoid, planetology, plane tree

How to use planetesimal in a sentence

So collisions alone, he argues, can’t explain how planetesimals form.
The pebbled path to planets|Stephen Ornes|May 27, 2021|Science News For Students
Then, you produce protoplanets by colliding those planetesimals with each other.
The pebbled path to planets|Stephen Ornes|May 27, 2021|Science News For Students
It drifts around in a disk, then piles up to form 100 kilometer-scale “planetesimals,” the real building blocks of the planets.
The Sight of Jupiter and Saturn Together Is a Beautiful Thing - Facts So Romantic|Sean Raymond & Sebastiaan Krijt|December 21, 2020|Nautilus
These planetesimals can keep growing by self-collisions but not by any new dust originating in the outer solar system.
The Sight of Jupiter and Saturn Together Is a Beautiful Thing - Facts So Romantic|Sean Raymond & Sebastiaan Krijt|December 21, 2020|Nautilus

Jupiter’s growing core—a super-big planetesimal about ten times the mass of Earth—may have done exactly that.
The Sight of Jupiter and Saturn Together Is a Beautiful Thing - Facts So Romantic|Sean Raymond & Sebastiaan Krijt|December 21, 2020|Nautilus
The Planetesimal Theory suggests that these thickened knots are embryo planets and the central portion of the nebul an embryo sun.
The Meaning of Evolution|Samuel Christian Schmucker
Let us now inquire briefly into the bearing of this planetesimal hypothesis upon the early geological history of the earth.
Geology|William J. Miller
On one point the new planetesimal theory differs from the other theories.
The Story of Evolution|Joseph McCabe
In deference to the opinion of a number of geologists we must glance once more at the alternative view of the planetesimal school.
The Story of Evolution|Joseph McCabe
But the planetesimal hypothesis has no room for this enormous percentage of carbon-dioxide in the primitive atmosphere.
The Story of Evolution|Joseph McCabe

Scientific definitions for planetesimal

planetesimal

[ plăn′ĭ-tĕs′ə-məl ]

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.