Nebular hypothesis

Nebular hypothesis, an hypothesis, framed by Laplace, to explain the process of formation of the solar system. It supposed the matter of the system to have existed originally in the form of a vast diffused, revolving nebula, which, gradually cooling and contracting, threw off, in obedience to mechanical and physical laws, successive rings of matter, from which subsequently, by the same laws, were produced the several planets, satellites, and other bodies of the system.