Einstein's general theory of relativity is known as general relativity. It is a generalised form of special theory of relativity. It also generalise Newton's law of universal Gravitation.
General relativity is a developed form of special theory of relativity. In 1905 Albert Einstein introduced a theorem that is concerned with non accelerating bodies. This is Einstein's special theory of relativity. According to Einstein's special theory of relativity, the law of physics is same for all non accelerating observers and in vacuum the peed of light is same and independence with the speed of observers travels. Einsteins special theory of relativity gives a concept of space time, where space and time concentrate into an unique continuum.
In order to obtain the theory of Gravitation from the principles of equivalence that says the law of physics must be same for all observers that is independent with the moving of observers there considers Newton's first law of motion. According to first law of motion if there exerted no force on object then moving object will remain moving in straight line. But few examples draws a limitation on the straight line moving conception of objects.
Movement of bullet is not in accurate straight line. If you through a stone it will never follow a straight line moving. These examples leads to a conclusion about gravity as a curvature of space time.
According to Einstein's conception gravity is not a force.
Let us discuss about space time curvature
Space time curvature
Massive mass and small mass objects shows different characteristics on producing curvature. Curvature depends on the massiveness of the objects. Massive weight objects are found to create more curvature. Massive weight is an object of strong gravitational field. Again, small mass of objects that moves nearby the large mass of objects that follows the path approximate closely to the shortest distance straight line.
Albert Einstein shows that curvature is dependent on both case of object with less mass and object with higher mass. The object with less mass that's have weak gravitational field will produce less curvature of space time. On the other hand the object with higher mass that's have strong gravitational field will produce high curvature of space time.
Development of special relativity and results as Einstein's general theory of relativity
Albert Einstein realised that to include accelerating body into special theory of relativity. He works 10 years to develop the special theory of relativity. In 1915 he introduced a new theorem that includes the acceleration that would be the result of earths gravitational field and called general theory of relativity or Einstein's general theory of relativity.
Einsteins general theory of relativity and gravity
Einsteins general theory of relativity gives us a conception of space time. It also provide a definition of gravity in modern physics. It says that gravitation is a geometric property of space and time. In Einstein field equation space time is related with energy and momentum and this does not depend on matter and radiation.
Einstein's general theory of relativity modified Newton's first law of motion. Where Newton's first law of motion where gives a conception of moving of objects on straight line there Einstein's general theory of relativity generalises straight line geodesic. Geodesic is a shortest distance between two point. Newtonian law is followed by the moving of object on Euclidean geometry. We know Euclidean geometry as a flat geometry where we find straight line. But due to earths gravitational field no object will find that will follow straight line moving. But object will move followed by curved geodesics
Einstein's general theory of relativity and Black hole relationship
Einsteins general relativity and black hole is interrelated. It gives us conception of existence of Black Hole. According to Einstein's general theory of relativity, Black Hole can define as a region in space where space and time distorted in such way that nothing can escape from it even light.
General relativity also gives us an idea of gravitational wave.
Not only that. General relativity is also an evidence of Big Bang theorem. It gives us a model of universe that is continuously expanding according to Big Bang theory.
Einstein's general theory of relativity also describes the phenomenon so called gravitational lensing.
General relativity gives the explanation of orbiting nature of Mercury about sun by elliptical path. Mercury is found to rotate slowly on moving around the sun. This is explains to happen due to strong gravitational field of more massive sun and a weak gravitational field of less massive Mercury.
Gravitational lensing
Light caused bent behind a massive object. This happenings is just like an act of an optical lens. This is termed as gravitational lensing. The most common examples of gravitational lensing is Einstein's cross and Quasar in Pegasus constellation
Previously it have been discussed that Einstein's general theory of relativity is difference from Newtonian classical mechanics in terms of motion of bodies. Another significant dissimilarity of general relativity from Newtonian classical mechanics is concerned with passage of time, geometry of space, and light propagation.
Limitation of general relativity
Einstein's general theory of relativity leads to the conception of originating of universe from infinite and dense state that we termed as singularity. But laws of physics have some opposed with singularity concept.
Another things is that general relativity is somewhat integrated with quantum theory. Gravitational force is incorporated with special theory of relativity.
