General relativity
General relativity generalizes special relativity and refines Newton’s law of universal gravitation. The predictions of general relativity in relation to classical physics have been confirmed in all observations and experiments to date. But unanswered questions remain, the most fundamental being how general relativity can be reconciled with the laws of quantum physics.
About General relativity in brief
General relativity, also known as the general theory of relativity, is the geometric theory of gravitation published by Albert Einstein in 1915. General relativity generalizes special relativity and refines Newton’s law of universal gravitation, providing a unified description of gravity. The predictions of general relativity in relation to classical physics have been confirmed in all observations and experiments to date. But unanswered questions remain, the most fundamental being how general relativity can be reconciled with the laws of quantum physics to produce a complete and self-consistent theory of quantum gravity. In 1917, Einstein applied his theory to the universe as a whole, adding a new parameter to his field equations—themological constant. By 1929, Hubble and others had shown that our universe is readily described by the expanding cosmological solutions found by Friedmann, Friedmann and Lemaître. During his later life, Einstein declared that the biggest blunder of his life was that the universe remained in an extremely hot and dense state in which our universe has evolved from an earlier version of the Big Bang to an expanding universe. In line with contemporary relativistic thinking, he assumed static universe to match his original presumption, however, this is not the case. In 1922, Einstein used these solutions to formulate the earliest version of his theory of the universe, which do not require a cosmologically constant. He later declared the BigBang to be something that had never been seen before in the history of our planet, the Earth, or the Sun. The theory has important astrophysical implications.
For example, it implies the existence of black holes—regions of space in which space and time are distorted in such a way that nothing, not even light, can escape—as an end-state for massive stars. There is ample evidence that the intense radiation emitted by certain kinds of astronomical objects is due to black holes. In 1916, the astrophysicist Karl Schwarzschild found the first non-trivial exact solution to the Einstein field equations, the Schwarzschild metric. This solution laid the groundwork for the description of the final stages of gravitational collapse, and the objects known today as black holes, such as microquasars and active galactic nuclei. The bending of light by gravity can lead to the phenomenon of gravitational lensing, in which multiple images of the same distant astronomical object are visible in the sky. General relativity also predicts theexistence of gravitational waves, which have since been observed directly by the physics collaboration LIGO. It has often been described as the most beautiful of all existing physical theories. It is the simplest theory that is consistent with experimental data and is widely acknowledged as a theory of extraordinary beauty. The equations specify how the geometry of space andTime is influenced by whatever matter and radiation are present. The 19th century mathematician Bernhard Riemann’s non-Euclidean geometry enabled Einstein to develop general relativity by providing the key mathematical framework on which he fit his physical ideas of gravity, this idea was pointed out by mathematician Marcel Grossmann.
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This page is based on the article General relativity published in Wikipedia (as of Dec. 06, 2020) and was automatically summarized using artificial intelligence.
