Nebular Hypothesis

From Encyclopediak

Nebular Hypothesis, a theory advanced by Laplace, Kant and others to account for the formation of the solar system. The foundation of the theory is the supposition that the bodies comprising the solar system were once a nebulous mass, this mass took a rotary motion on its axis, from east to west as the temperature diminished and the nebula contracted the rapidity of rotation increased and zones or rings of nebulous matter were separated. Each of these zones contracted into a spherical body forming a planet, which revolves in the orbit that the zone occupied. The planets in turn by rotation separated themselves from rings which became satellites, which in case of Saturn are still seen in the original form of the zone, constituting the rings of that planet. In proof of the correctness of this theory its advocates claim that the orbits of the planets around the sun and the planes of their rotation upon their axes very nearly coincide that the direction of revolution around the sun is the same for all planets except Uranus and Neptune that the satellites of the planets, as a rule, also revolve around their respective planets in the same direction and still further that the rotation of the planets and satellites on their axes is in this same direction all of which suggests that millions of years ago the sun, at that time a cloud of gas, was pitched whirling into space, condensing and throwing off portions of itself as it whirled. The nebular hypothesis is not now so generally accepted as formerly. See ASTRONOMY LAPLACE, PIERRE SIMON NEWTON, SIR ISAAC.