Nebular hypothesis
The nebular hypothesis is a theory published by Pierre-Simon Laplace in his work Exposition du système du monde (“Representation of the World System”) in 1796 on the formation of the solar system from a solar nebula .
hypothesis
Laplace assumed a gaseous atmosphere that surrounded the sun and, due to excessive heating, filled the entire area of today's solar system. Its atmosphere revolved around the sun, and as the sun cooled, the atmosphere shrank and matter condensed. Because of the conservation of angular momentum , the rotation of the atmosphere accelerated. As a result, the atmosphere flattened and assumed a lenticular shape. With further compression and the corresponding increase in rotation, the centrifugal force in the outer gas region eventually became so great that it overcame the gravitational force of the sun and a gas ring detached itself from the atmosphere in the equatorial plane, which continued to rotate around the sun. This process was repeated a few times until the solar atmosphere had shrunk to its current volume. The matter of the gas rings condensed further, so that solid bodies were formed. Of these solid bodies, one body was dominant for each gas ring, so that it attracted the other bodies and "swallowed" them. As a result, the body grew into a planet over time. This had so much mass that the remaining gas was attracted to it and became its atmosphere. Similar to the sun, the satellites of the planets were created as the gas cooled down further.
meaning
Laplace's cosmogony works completely without God . Up to this point in time only Immanuel Kant had completely dispensed with the mention of God in his work General Natural History and Theory of Heaven with a similar theory in 1755 . Laplace, however, had no knowledge of Kant's theory. This work by Kant received little attention and was only rediscovered 100 years later by François Arago . Together they are called the Kant-Laplace theory today .
Laplace set up his theory almost entirely without any technical aids (except telescopes ). Nevertheless, despite criticism, the Kant-Laplace theory has been recognized as a popular theory for over 100 years. It was only discarded at the beginning of the 20th century, only to be included again in a modified form in 1960.
See also
literature
- Traité de mécanique céleste. Five volumes, Paris 1798–1825 (reprinted, Brussels 1967). Translated into English under the title: Celestial mechanics . Chelsea Publications, Bronx, NY 1976, ISBN 0-8284-0214-0 (5 vols.)
- Manfred Jacobi: Pierre-Simon Laplace and the representation of the world system - "The most beautiful monument of the human spirit". In: Physics in our time, Vol. 41, No. 2, 2010, ISSN 0031-9252 , pp. 82-86