protoplanet

noun
pro·​to·​plan·​et | \ˈprō-tō-ˌpla-nət \

Definition of protoplanet 

: a hypothetical whirling gaseous mass within a giant cloud of gas and dust that rotates around a sun and is believed to give rise to a planet

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Other Words from protoplanet

protoplanetary \ˌprō-​tō-​ˈpla-​nə-​ˌter-​ē \ adjective

Examples of protoplanet in a Sentence

Recent Examples on the Web

The discoveries, and the new method used to make them, are a thrilling advancement of exoplanet sciences to include protoplanets still in the process of formation, which were previously hidden from view. Jay Bennett, Popular Mechanics, "Three Newborn Planets Discovered Around an Infant Star," 13 June 2018 Fortunately, the study of protoplanets is just getting started. Jay Bennett, Popular Mechanics, "Three Newborn Planets Discovered Around an Infant Star," 13 June 2018 Therefore, the meteorite diamonds reveal information about their parent protoplanet. Doris Elin Salazar, Scientific American, "Diamonds in Meteorite May Come from a Lost Planet," 18 Apr. 2018 The diamonds themselves may have been larger until the protoplanet was destroyed. John Wenz, Popular Mechanics, "Diamond-Encrusted Meteorite Could Be From a Lost Planet," 17 Apr. 2018 The diamond pieces inside the meteorite hold a compelling record of these protoplanets and their collisions, according to the study. Doris Elin Salazar, Scientific American, "Diamonds in Meteorite May Come from a Lost Planet," 18 Apr. 2018 The protoplanet in question may have originated in the outer solar system and migrated inward to the inner solar system. John Wenz, Popular Mechanics, "Diamond-Encrusted Meteorite Could Be From a Lost Planet," 17 Apr. 2018 As Sarah Gibbens at National Geographic reports, in the first 10 million years of our planetary family, swarms of protoplanets composed of rock, dust and gas likely pinballed around the sun. Jason Daley, Smithsonian, "Diamonds Trapped in Strange Meteorite Came From Solar System’s Earliest Planets," 19 Apr. 2018 In the study, a research team found that the Almahata Sitta meteorite once belonged to a protoplanet, one of tens of early worlds that experienced impacts and buildups to ultimately create the rocky planets in our solar system. Doris Elin Salazar, Scientific American, "Diamonds in Meteorite May Come from a Lost Planet," 18 Apr. 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'protoplanet.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of protoplanet

1949, in the meaning defined above

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The first known use of protoplanet was in 1949

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