Gμν = -(8πG/c²)Tμν
This elegant symbolic formulation of Einstein’s general theory of relativity cannot be used for actual calculations, but it clearly shows the principle that “matter tells spacetime how to curve, and curved space tells matter how to move” (John Wheeler, Princeton University and the University of Texas at Austin) . The left side of the equation contains all the information about how space is curved, and the right side contains all the information about the location and motion of the matter. General relativity is beautiful and simple (to a physicist), but mathematically it’s very complicated and subtle.
Of course, General Relativity as formulated by Albert Einstein is an approximation. It says nothing for instance about ‘dark’ matter or energy, which make up the bulk of the ‘stuff’ our Universe is made of. It is also mathematically incompatible with Quantum theory. But I think you’ll agree that Herr Doktor Einstein made a pretty decent stab at the problem!
An interesting and pretty accurate historical survey of our changing views of the Universe over the centuries: