People
Pythagoras
Euclid
Galileo
Newton
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Lorentz
Minkowski
Einstein
Albert Einstein
In 1905, Albert Einstein, aged 26, published his original theory of relativity, which is now known as the Special Theory of Relativity. Although it is indirectly based on the Galilean concept of relativity "all motion is relative", it was actually based on two other ideas. The first was Einstein's Principle of Relativity:
"The same laws of electrodynamics and optics will be valid for all frames of reference for which the equations of mechanics hold good".
The second was Einstein's Second Postulate:
"Light is always propagated in empty space with a definite velocity c which is independent of the state of motion of the emitting body".
This second postulate is not a simple as it may seem, and we discuss it further here.
In 1915 Einstein published his General Theory of Relativity. This drew on his earlier work, but also included the four dimensional spacetime continuum, tensor calculus, and his own work on gravity. This theory was therefore based on a different conceptual framework from the Special Theory. Nowadays, the term "special relativity" usually refers to the special case of the General Theory in which the gravitational field is uniform. Hence it is analogous to, but not the same as, Einstein's original theory.
Further information on Special Relativity may be found here.
Further information on Einstein's life may be found here.
