The theory of relativity, which is also simply called relativity, specifically refers to two theories, namely the theory of special relativity which was propounded by Albert Einstein and the theory of general relativity. The term relativity was coined by Max Planck in the year 1908. It emphasised how the principle of relativity is used by relativity, and later general relativity.
In the year 1905, Albert Einstein introduced the theory of special relativity, which was a theory of spacetime. It stated that when the observers are in uniform motion which is relative to one another, they have no way to determine whether one of them is stationary and that the speed of light in a vacuum is the same for all the observers, irrespective of their motion or that of the source of light. One of the most well-known consequences of Einstein's theory of relativity was E=mc2, which shows that energy and mass are interchangeable.
In the year 1905, Albert Einstein introduced the theory of special relativity, which was a theory of spacetime. It stated that when the observers are in uniform motion which is relative to one another, they have no way to determine whether one of them is stationary and that the speed of light in a vacuum is the same for all the observers, irrespective of their motion or that of the source of light. One of the most well-known consequences of Einstein's theory of relativity was E=mc2, which shows that energy and mass are interchangeable.
