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
Example Sentences
Recent Examples on the Web The most massive objects in the disk are called planetesimals, and their locations are shaped by interactions with other planets in the system. 
Meredith A. Macgregor, Scientific American, 19 May 2020 In the case of Mars, two different planetesimals with very different water content could have collided and never fully mixed, the researchers said. Ashley Strickland, CNN, 30 Mar. 2020 The timing would be fortuitous, given the mounting detections of individual planetesimals outside of the Solar System. Jennifer Ouellette, Ars Technica, 14 Apr. 2020 Its uniform color, smooth surface and how the lobes came together help piece together a picture of how the planetesimal came to be. Ashley Strickland, CNN, 13 Feb. 2020 Except there seems to be a crucial bottleneck in this planetary assembly line: the jump from pebbles to kilometer-scale building blocks called planetesimals. Lee Billings, Scientific American, 20 Feb. 2020 Studying Arrokoth can shed light on how the building blocks of planets, called planetesimals, formed in our solar system. Ashley Strickland, CNN, 13 Feb. 2020 If this planetesimal was once Earth-like, as Manser believes, the outcome is bleak. Catherine Zuckerman, National Geographic, 4 Apr. 2019 As the story goes, Mercury suffered a stupendous collision near the end of the period of planetary accretion, struck by a planetesimal so big that much of its crust was blasted into space. Kim Stanley Robinson, National Geographic, 22 Mar. 2019 See More
Meredith A. Macgregor, Scientific American, 19 May 2020 In the case of Mars, two different planetesimals with very different water content could have collided and never fully mixed, the researchers said. Ashley Strickland, CNN, 30 Mar. 2020 The timing would be fortuitous, given the mounting detections of individual planetesimals outside of the Solar System. Jennifer Ouellette, Ars Technica, 14 Apr. 2020 Its uniform color, smooth surface and how the lobes came together help piece together a picture of how the planetesimal came to be. Ashley Strickland, CNN, 13 Feb. 2020 Except there seems to be a crucial bottleneck in this planetary assembly line: the jump from pebbles to kilometer-scale building blocks called planetesimals. Lee Billings, Scientific American, 20 Feb. 2020 Studying Arrokoth can shed light on how the building blocks of planets, called planetesimals, formed in our solar system. Ashley Strickland, CNN, 13 Feb. 2020 If this planetesimal was once Earth-like, as Manser believes, the outcome is bleak. Catherine Zuckerman, National Geographic, 4 Apr. 2019 As the story goes, Mercury suffered a stupendous collision near the end of the period of planetary accretion, struck by a planetesimal so big that much of its crust was blasted into space. Kim Stanley Robinson, National Geographic, 22 Mar. 2019 See More Word History
Etymology
planet + -esimal (as in infinitesimal)
First Known Use
1903, in the meaning defined above