Albert Einstein’s theory of General Relativity (GR) replaced Isaac Newton’s theory of Classical Gravity as the most accurate description of gravitation. Specifically, General Gravity transforms the concept of gravity from a force between objects to a property of spacetime. Black holes are one of the many fascinating consequences of General Relativity. (See also Special Relativity.)
The gluon is a boson that mediates the strong interaction. Gluons are hypothesized to interact with each other to form transient composite structures called glueballs.