planetesimal
[ plan-i-tes-uh-muh l ]
/ ˌplæn ɪˈtɛs ə məl /
noun
one of the small celestial bodies that, according to one theory (planetesimal hypothesis), were fused together to form the planets of the solar system.
adjective
of or relating to a planetesimal or planetesimals.
Origin of planetesimal
First recorded in 1900–05;
planet +
(infinit)esimal
Words nearby planetesimal
planetarian,
planetarium,
planetary,
planetary nebula,
planetary precession,
planetesimal,
planetesimal hypothesis,
planetoid,
planetology,
planform,
plangent
British Dictionary definitions for planetesimal hypothesis
planetesimal hypothesis
/ (ˌplænɪˈtɛsɪməl) /
noun
the discredited theory that the close passage of a star to the sun caused many small bodies (planetesimals) to be drawn from the sun, eventually coalescing to form the planets
Word Origin for planetesimal hypothesis
C20:
planetesimal, from
planet +
infinitesimal
Scientific definitions for planetesimal hypothesis
planetesimal
[ plăn′ĭ-tĕs′ə-məl ]
Any of innumerable small bodies of accreted gas and dust thought to have orbited the Sun during the formation of the planets.♦ The theory that explains the formation of the solar system in terms of the aggregation of such bodies is known as the planetesimal hypothesis. According to this theory, first proposed in 1900, the planetesimals formed within a spiral disk of dust and gas surrounding a central nucleus. Their gravitational attraction eventually caused the planetesimals to coalesce into protoplanetary disks from which larger objects such as planets, asteroids, and satellites were formed, while the nucleus coalesced into the Sun.