General Theory of Relativity
General Relativity is a theory of gravitation developed and published by Albert Einstein in 1916. Once when Einstein was preparing for a review of his theory of relativity, he thought about the fact that a man falling from the roof of a building doesn't feel his own weight. This idea, which he called "The happiest thought of my life", (Brian Greene, The fabric of the Cosmos) was the reason that led Einstein to develop the theory of General Relativity. General relativity is not a difficult theory to comprehend like most of other scientific theories, even though the mathematics of it are complex and involve curved space geometry that is not easy to understand. Albert Einstein had problems with the mathematics of this remarkable theory for few years before he got to the “precise version of his famous field equation, and this equation looks very simple, but it actually involves ten different differential equations, and cannot be used in practice as it is (Walter B. Keighton, Physics: Its Laws, Ideas, And Methods).
Albert Einstein, after publishing his final paper of relativity, he totally did not expect precise solutions for his complex equation to come. Unexpectedly, a German physicist known as the father of astrophysics, Karl Schwarzschild has found an exact solution for this equation couple months after Albert Einstein published the final paper of the General theory of Relativity in 1916 (Charles D. Hodgman). This solution he got defines the gravity field around a massive static spherical body. The other solutions were found in the sixties when new mathematical tools and computers were developed.
In 1907 Albert Einstein published a paper on acceleration under special relativity where he claimed that free fall is really inertial motion, and that the laws of special relativity would apply on the person who’s in free fall. This idea is called the Equivalence principle. Consequently, Albert Einstein “predicted the phenomena of gravitation time dilation in which gravity has an effect on the rate of time” (Brian Greene). Accordingly 1911 was the year when Einstein wrote another paper where he went further more on the paper he published in 1907. Where he came up with a conclusion in which the rates of time is affected mostly by the position in a gravitational field. In this article “Einstein anticipated light deflection by massive bodies as a result of mathematical calculations.” (Dennis Overbye, New York Times) In 1912, Albert Einstein went back to Switzerland to receive a prize and he went to an old classmate called Marcel Grossman where he introduced him to differential geometry in which it helped very much in developing the theory. Following these events Albert Einstein published his final paper of General Theory of Relativity. The Theory that Albert Einstein came up with explains very deeply the structure of space-time by matter, and how massive objects affect each other in space. In may of 1919, a group of scientists led by Arthur Stanley Eddington – a famous British astronomer – declared that they had confirmed Einstein’s idea of gravitational deflection which is a very important element in the general theory of relativity. “General relativity predicted the bending of light, the expansion of the universe and black holes, and has served as the foundation for modern cosmology” (Dennis Overvye, New York Times.)
3). Components of General theory of Relativity
(Astronomy notes. May, 2012)
Fabric of spacetime: The picture above is a visual interpretation of the fabric of space time. It consists of 4 dimensions; the three dimensions of space and one of time. 2.
Massive Bodies: The image below shows how the fabric of space time is affected by massive bodies.The Mass will cause a dent in the space-time fabric. Much like a boulder placed in the riverflow, time will curve around the mass and will be slower. The farther away you move from the...
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