protoplanet

American  

[proh-toh-plan-it] / ˈproʊ toʊˌplæn ɪt /

noun

Astronomy.

1. the collection of matter, in the process of condensation, from which a planet is formed.

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protoplanet British  

/ ˌprəʊtəʊˈplænɪt /

noun

1. a planet in its early stages of evolution by the process of accretion

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Etymology

Origin of protoplanet

First recorded in 1945–50; proto- + planet

Example Sentences

See Examples For:

protoplanet

Scientists now say they have found the first direct evidence that this long-lost planetary embryo, known as a protoplanet, once existed.

From Science Daily ● Jun. 23, 2026

A giant collision between the young Earth and a smaller protoplanet has long been the prevailing theory for the Moon’s formation.

From Scientific American ● Nov. 2, 2023

The collision was so powerful, it broke apart that impacting protoplanet, nicknamed Theia, and sent huge amounts of material into orbit around Earth—material that eventually coalesced into the moon.

From National Geographic ● Nov. 1, 2023

But scientists have lacked smoking-gun evidence like a crater or pieces of the protoplanet, named Theia.

From New York Times ● Nov. 1, 2023

For decades, scientists have wondered whether Psyche could be the denuded metal core of a larger protoplanet.

From Science Magazine ● Oct. 13, 2023