The theory of general relativity (or general relativity for short) is the fundamental building block of modern physics. It explains gravity based on how space can “bend” or, more accurately, it relates the gravitational force to a change in the geometry of spacetime.

History of general relativity theory

Albert Einstein based his “general” theory in 1915, a decade after he introduced “special” relativity, which applied the universal speed of light to the assumption that the laws of physics remain the same in any frame of reference.

When Einstein tried to apply accelerating masses to his particular theory, he realized that objects with mass must somehow affect the surrounding dimensions (space-time), so that the object behaves as if it were attracting other masses. Matter appears to weigh down the fabric of space-time in which it resides, creating a “curve” that forces other nearby matter to shift towards it.

The value of the general theory of relativity

The repeatedly tested mathematical equations of Einstein’s theory of general relativity are currently the most accurate way to predict gravitational interactions, replacing those developed by Isaac Newton several centuries ago.

As useful as they are, we do not yet have an equivalent in quantum field theories due to significant incompatibilities. For example, quantum mechanics has ways of explaining concepts like infinity, but if we try to do the same for general relativity, the math will produce predictions that don’t make sense.

The development of a “version” of quantum physics’ general theory of relativity remains an abiding goal of modern physics. Source