nebular hypothesis

n. A hypothesis concerning the formation of stars and planets, and therefore the origin of the solar system, according to which a rotating nebula underwent gravitational collapse into a star with an accretion disk, from which planets condensed or formed by coagulation of dust particles into increasingly larger bodies.

nebular hypothesis

n (Astronomy) the theory that the solar system evolved from the gravitational collapse of nebular matter

neb′ular hypoth′esis

n. the theory that the solar system evolved from a mass of nebular matter. [1830–40]

neb·u·lar hypothesis

(nĕb′yə-lər) An explanation of the origin of the solar system according to which a rotating nebula cooled and contracted, flattening into a disk shape with a central bulge. The matter in the disk condensed into the planets, their moons, asteroids, and comets, while the great mass at the center became the sun.

Thesaurus

Noun

nebular hypothesis - (cosmology) the theory that the solar system evolved from a hot gaseous nebulascientific theory - a theory that explains scientific observations; "scientific theories must be falsifiable"cosmogeny, cosmogony, cosmology - the branch of astrophysics that studies the origin and evolution and structure of the universe

nebular hypothesis

nebular hypothesis:

see solar systemsolar system,
the sun and the surrounding planets, natural satellites, dwarf planets, asteroids, meteoroids, and comets that are bound by its gravity. The sun is by far the most massive part of the solar system, containing almost 99.9% of the system's total mass.
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nebular hypothesis

(neb -yŭ-ler) A theory for the origin of the Solar System put forward by the French mathematician Pierre-Simon de Laplace in 1796 and similar to a suggestion of the philosopher Immanuel Kant in 1755. It was proposed that the Solar System formed from a great rotating cloud, or nebula, of material (gas and dust) collapsing under its own gravitational attraction. An interaction of forces caused the cloud to form a rotating flattened disk, called the solar nebula. To conserve angular momentum, the disk rotated more rapidly as the contraction progressed. Laplace suggested that rings of material became detached from the spinning disk when the velocity at its edge exceeded a critical value, and that the material in these rings later coalesced to form the planets. The central product of the contraction is the Sun, while the planetary satellites may have formed from further rings shed by the condensing planets.

The hypothesis, popular throughout the 19th century, went out of favor. The main problem was that it indicated that the Sun should still be spinning on the verge of rotational instability; it could not explain why the Sun has almost 99.9% of the mass of the Solar System but only about 2% of the total angular momentum. In addition, calculations showed that the rings would not condense to form planets. However, in a modified form, it is the basis of most modern ideas for the formation of the Sun and planets. See Solar System, origin. Compare encounter theories.

Nebular Hypothesis

a cosmogonical hypothesis which assumes that the solar system (and celestial bodies in general) was formed out of a rarefied nebula. The term “nebular hypothesis” originated in the 19th century in connection with the Laplace nebular hypothesis. Later, the term was also used in Kant’s hypothesis and in other theories that assumed the formation of celestial bodies from nebulae of gas or dust. The term “nebular hypothesis” is not usually used in relation to modern cosmogonical hypotheses. (SeeCOSMOGONY.)

nebular hypothesis

[′neb·yə·lər hī′päth·ə·səs] (astrophysics) A theory, proposed in 1796 by Laplace, supposing that the planets originated from the solar nebula surrounding the proto-sun; as the sun cooled, it contracted, rotated faster, and thus caused a ringlike bulging at the equator; this bulge eventually broke off and formed the planets; Laplace further theorized that the sun and other stars formed from clouds of nebulous matter; the theory in this form is not accepted.

nebular hypothesis

nebular hypothesis

nebular hypothesis

neb′ular hypoth′esis

neb·u·lar hypothesis

nebular hypothesis

nebular hypothesis:

nebular hypothesis

Nebular Hypothesis

nebular hypothesis

nebular hypothesis

Words related to nebular hypothesis

noun (cosmology) the theory that the solar system evolved from a hot gaseous nebula

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