protoplanet
Americannoun
noun
Etymology
Origin of protoplanet
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.
About 4.5 billion years ago, a dramatic event transformed the young Earth when a large protoplanet known as Theia struck our planet.
From Science Daily • Nov. 23, 2025
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
The arms could be a sign of a cloud collapsing under its own gravity, or they could indicate a massive protoplanet drawing the cloud in.
From Science Magazine • Apr. 3, 2022
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.
