planetesimal

noun

plan·​e·​tes·​i·​mal ˌpla-nə-ˈte-sə-məl 

-zə-məl

: any of numerous small celestial bodies that may have existed at an early stage of the development of the solar system

Examples of planetesimal in a Sentence

Recent Examples on the Web

To test the idea, the team conducted more than 3,000 simulations modeling what happens when stars of different masses fly through planetesimal disks of different widths, passing at different distances. —Michael Irving, New Atlas, 12 Sep. 2024

Such an event may have even brought about a cataclysmic period known as the Late Heavy Bombardment—when planetesimals peppered the inner solar system and potentially forged many of the craters that pockmark the surface of the moon today. —Shi En Kim, Smithsonian Magazine, 22 May 2024

The gravity of a passing star can eject smaller bodies, known as planetesimals, from the outer reaches of a system, according to a recent study led by Pfalzner. —Theo Nicitopoulos, Discover Magazine, 17 Feb. 2024

Instead, it may have been ejected during the death throes of its star: Pulses of gas from a dying star could push planets and planetesimals outward, destabilizing their orbits enough to send some of them flying into interstellar space. —Theo Nicitopoulos, Discover Magazine, 17 Feb. 2024

Word History

Etymology

planet + -esimal (as in infinitesimal)

First Known Use

1903, in the meaning defined above

Phrases Containing planetesimal

• planetesimal hypothesis

Kids Definition

planetesimal

noun

plan·​e·​tes·​i·​mal ˌplan-ə-ˈtes-ə-məl 

-tez-

: one of numerous small solid heavenly bodies which may have existed at an early stage of the development of the solar system and from which the planets may have been formed