General Relativity
In 1915, Albert Einstein developed his theory of general relativity, having earlier shown that gravity does influence light's motion. Only a few months later, Karl Schwarzschild found a solution to Einstein field equations, which describes the gravitational field of a point mass and a spherical mass. A few months after Schwarzschild, Johannes Droste, a student of Hendrik Lorentz, independently gave the same solution for the point mass and wrote more extensively about its properties. This solution had a peculiar behaviour at what is now called the Schwarzschild radius, where it became singular, meaning that some of the terms in the Einstein equations became infinite. The nature of this surface was not quite understood at the time. In 1924, Arthur Eddington showed that the singularity disappeared after a change of coordinates (see Eddington–Finkelstein coordinates), although it took until 1933 for Georges Lemaître to realize that this meant the singularity at the Schwarzschild radius was an unphysical coordinate singularity.
In 1931, Subrahmanyan Chandrasekhar calculated, using special relativity, that a non-rotating body of electron-degenerate matter above a certain limiting mass (now called the Chandrasekhar limit at 1.4 solar masses) has no stable solutions. His arguments were opposed by many of his contemporaries like Eddington and Lev Landau, who argued that some yet unknown mechanism would stop the collapse. They were partly correct: a white dwarf slightly more massive than the Chandrasekhar limit will collapse into a neutron star, which is itself stable because of the Pauli exclusion principle. But in 1939, Robert Oppenheimer and others predicted that neutron stars above approximately three solar masses (the Tolman–Oppenheimer–Volkoff limit) would collapse into black holes for the reasons presented by Chandrasekhar, and concluded that no law of physics was likely to intervene and stop at least some stars from collapsing to black holes.
Oppenheimer and his co-authors interpreted the singularity at the boundary of the Schwarzschild radius as indicating that this was the boundary of a bubble in which time stopped. This is a valid point of view for external observers, but not for infalling observers. Because of this property, the collapsed stars were called "frozen stars," because an outside observer would see the surface of the star frozen in time at the instant where its collapse takes it inside the Schwarzschild radius.
Read more about this topic: Black Hole, History
Other articles related to "general relativity, relativity, general":
... General relativity typically deals with situations involving large mass objects in fairly large regions of spacetime whereas quantum mechanics is generally ... at Planck scale (a fundamental small unit of length) lengths, general relativity predicts a smooth, flowing surface, while quantum mechanics predicts a random, warped surface, neither ...
... This is "special relativity" as usually understood ... This is non-gravitational physics plus general covariance ... This is the sense in which "special relativity" can handle accelerated frames ...
... Stanley Deser is an American physicist known for his contributions to general relativity ... In the context of general relativity, he is best known for his development (with Richard Arnowitt and Charles Misner) of the ADM formalism, roughly speaking a way of describing spacetime as space ... mass (so-called ADM mass/energy) which, in general relativity, is not trivial at all ...
... are solutions of the field equations of general relativity which describe "warp drives" (such as the Alcubierre metric) and stable, traversable wormholes ... some configuration of the stress–energy tensor field (see exact solutions in general relativity) ... General relativity does not constrain the geometry of spacetime unless outside constraints are placed on the stress–energy tensor ...
... General relativity has emerged as a highly successful model of gravitation and cosmology, which has so far passed many unambiguous observational and experimental tests ... Even taken as is, general relativity is rich with possibilities for further exploration ... More than ninety years after its publication, general relativity remains a highly active area of research ...
Famous quotes containing the words relativity and/or general:
“By an application of the theory of relativity to the taste of readers, to-day in Germany I am called a German man of science, and in England I am represented as a Swiss Jew. If I come to be regarded as a bête noire the descriptions will be reversed, and I shall become a Swiss Jew for the Germans and a German man of science for the English!”
—Albert Einstein (18791955)
“The happiest conversation is that of which nothing is distinctly remembered but a general effect of pleasing impression.”
—Samuel Johnson (17091784)