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The nebular hypothesis is the most widely accepted model in the field of cosmogony to explain the formation and evolution of the Solar System (as well as other planetary systems). It suggests the Solar System is formed from gas and dust orbiting the Sun which clumped up together to form the planets.
The most widely accepted model of planetary formation is known as the nebular hypothesis.This model posits that, 4.6 billion years ago, the Solar System was formed by the gravitational collapse of a giant molecular cloud spanning several light-years.
The nebular hypothesis says that the Solar System formed from the gravitational collapse of a fragment of a giant molecular cloud, [9] most likely at the edge of a Wolf-Rayet bubble. [10] The cloud was about 20 parsecs (65 light years) across, [9] while the fragments were roughly 1 parsec (three and a quarter light-years) across. [11]
The nebular hypothesis of solar system formation describes how protoplanetary disks are thought to evolve into planetary systems. Electrostatic and gravitational interactions may cause the dust and ice grains in the disk to accrete into planetesimals .
Professor of biology Jerry Coyne sums up biological evolution succinctly: [3]. Life on Earth evolved gradually beginning with one primitive species – perhaps a self-replicating molecule – that lived more than 3.5 billion years ago; it then branched out over time, throwing off many new and diverse species; and the mechanism for most (but not all) of evolutionary change is natural selection.
The Chamberlin–Moulton planetesimal hypothesis was proposed in 1905 by geologist Thomas Chrowder Chamberlin and astronomer Forest Ray Moulton to describe the formation of the Solar System. It was proposed as a replacement for the Laplacian version of the nebular hypothesis that had prevailed since the 19th century.
A protostar is a very young star that is still gathering mass from its parent molecular cloud.It is the earliest phase in the process of stellar evolution. [1] For a low-mass star (i.e. that of the Sun or lower), it lasts about 500,000 years. [2]
Neutral theory – Theory of evolution by changes at the molecular level; Shifting balance theory – One version of the theory of evolution; Price equation – Description of how a trait or gene changes in frequency over time; Coefficient of relationship – Measure of biological relationship between individuals