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

The chaos would have influenced the size, location, and composition of the rocky planets, and many researchers believe it could also explain why a Mars-size protoplanet crashed into Earth around this time, creating the Moon.

From Science Magazine ● Apr. 16, 2024

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

The most popular theory says that about 4.5 billion years ago, a Mars-size protoplanet slammed into Earth.

From New York Times ● Nov. 1, 2023

"We think the Earth-Moon system formed following a giant impact between early Earth and another protoplanet," said Rufu, a Sagan Fellow who is the second author of a Science Advances paper.

From Science Daily ● Sep. 18, 2023