Einstein's Theory of Relativity is a theory that describes the relationship between space, time, and gravity.

Einstein's Theory of Relativity consists of two main parts: General Relativity and Special Relativity.

The principle of equivalence states that the laws of physics are the same for all observers in uniform motion.

The speed of light in a vacuum is approximately 300,000 kilometers per second, 299,792,458 meters per second, and 186,282 miles per second.

The equation for mass-energy equivalence is $E=mc^2$, where $E$ is energy, $m$ is mass, and $c$ is the speed of light.

Time dilation is the phenomenon that occurs when an object approaches the speed of light, causing time to slow down for that object.

Length contraction is the phenomenon that occurs when an object is accelerated, causing its length to decrease in the direction of motion.

Gravitational lensing is the phenomenon that occurs when light passes through a gravitational field, causing it to bend and distort.

A singularity is the name of the singularity that occurs at the center of a black hole, where the curvature of spacetime becomes infinite.

The event horizon is the name of the boundary around a black hole from which nothing, not even light, can escape.

A wormhole is the name of the hypothetical tunnel that connects two different points in spacetime.

A quasar is the name of the bright, active galactic nucleus that is powered by a supermassive black hole.

Albert Einstein is credited with developing the theory of general relativity.

The theory of general relativity was first published in 1915.

The Hafele-Keating experiment confirmed the predictions of general relativity.