Definition of planetesimal in English:


Line breaks: planet|esi¦mal
Pronunciation: /ˌplanɪˈtɛsɪm(ə)l


  • A minute planet; a body which could come together with many others under gravitation to form a planet.
    More example sentences
    • Asteroids are small bodies in space - the numerous leftover planetesimals from which the planets were made nearly 4.6 billion years ago.
    • Although planets, moons and planetesimals may seem to be very different astronomically, their common origin shows that this is not so.
    • As planetesimals grow still larger, their gravitational attraction increases, allowing them to become even more effective at accreting nearby planetesimals.


Back to top  
  • Denoting or relating to planetesimals: the planetesimal material orbiting the sun
    More example sentences
    • Models of planetesimal disks suggest that low relative velocities between the bodies produce accretion (objects hit and stay together) rather than fragmentation (objects break up and disperse).
    • His greatest contribution, however, was his planetesimal hypothesis of the origin of the planets.
    • After all, planetesimal sized portions of the Solar System cannot be considered to be orbiting the Earth, except in the obvious case of the Moon.


early 20th century: from planet, on the pattern of infinitesimal.

More definitions of planetesimal

Definition of planetesimal in:

Get more from Oxford Dictionaries

Subscribe to remove adverts and access premium resources

Word of the day astrogation
Pronunciation: ˌastrə(ʊ)ˈgeɪʃ(ə)n
(in science fiction) navigation in outer space