85
edits
Changes
Jump to navigation
Jump to search
Line 1:
Line 1: + +
General theory of relativity (view source)
Revision as of 13:10, November 13, 2009
, 13:10, November 13, 2009Added a paragraph that tries to concisely explain what the theory is and how it relates to Newton. More to come.
The '''general theory of relativity''' is a theory of gravity that is compatible with [[Special theory of relativity|Special Relativity]]. The theory was first published by [[Albert Einstein]] in 1916.
The '''general theory of relativity''' is a theory of gravity that is compatible with [[Special theory of relativity|Special Relativity]]. The theory was first published by [[Albert Einstein]] in 1916.
The general theory of relativity is a ''metric theory,'' sometimes also called a ''geometric theory.'' Metric theories describe physical phenomena in terms of [[differential geometry]]. This stands in contrast to Isaac Newton's [[Law of Universal Gravitation|law of universal gravitation]], which described gravity in terms of a [[vector field]]. In the case of general relativity, the theory relates ''stress-energy'' — an extension of the concept of [[mass]] — and the [[curvature]] of [[spacetime]]. In the words of physicist John Wheeler, "Space tells matter how to move, matter tells space how to curve."<ref>Misner, Thorne & Wheeler. ''Gravitation.'' (1973)</ref> In the [[weak field approximation]], where velocities of moving objects are low and gravitational fields are not very severe, the theory of general relativity is said to ''reduce to'' the law of universal gravitation. That is to say, under those circumstances the equations of general relativity are mathematically equivalent to the equations of Newtonian gravitation.
The theory was inspired by a thought experiment developed by Einstein involving two elevators. The first elevator is stationary on the Earth, while the other is being pulled through space at a constant acceleration of g. Einstein realized that any physical experiment carried out in the elevators would give the same result. This realization is known as the equivalence principle and it states that accelerating frames of reference and gravitational fields are indistinguishable. General Relativity is the theory of gravity that incorporates Special Relativity and the equivalence principle.
The theory was inspired by a thought experiment developed by Einstein involving two elevators. The first elevator is stationary on the Earth, while the other is being pulled through space at a constant acceleration of g. Einstein realized that any physical experiment carried out in the elevators would give the same result. This realization is known as the equivalence principle and it states that accelerating frames of reference and gravitational fields are indistinguishable. General Relativity is the theory of gravity that incorporates Special Relativity and the equivalence principle.