the theory of mechanics for objects moving with velocities close to the speed of light.

The observable effects on a body in motion. As velocity increases, time slows down, mass increases and lengths contract.

part of Einstein's theory relating to observers moving uniformly with respect to each other.

a theory invented by Albert Einstein to describe measurements of length and time for objects moving at constant velocity. Although it applies to all motion at constant velocity, it must be used instead of Newton's laws of motion at speeds of greater than about ten percent the speed of light.

The theory that the laws of nature are the same for all observers in unaccelerated motion and the speed of light is independent of the motion of its source. Einstein postulated that the time interval between two events was longer for an observer in whose frame of reference the events occur in different places than for the observer for whom they occur at the same place.

Einstein’s theory based on the idea that the laws of science should be the same for all observers, no matter how they are moving, in the absence of gravitational phenomena.

The physical theory of space and time developed by Einstein in 1905. It states that all the laws of physics are equally valid in all frames of reference moving at a uniform velocity, and that the speed of light is constant regardless of what frame of reference the observer is in. It also proposed that matter can be converted to energy and vice versa. In 1916 Einstein published his General Theory of Relativity, which added the effects of gravity to Special Relativity.

kinematic theory that explains the relations between light and matter (see relativity)

The specific set of rules relating observations from one frame of reference to the observations of the same phenomenon in another frame of reference. It states that the speed of light is the same for all observers. It also equates matter and energy through the equation E = mc.

The physical theory of space and time developed by Albert Einstein, based on the postulates that all the laws of physics are equally valid in all frames of reference moving at a uniform velocity, and that the speed of light from a uniformly moving source is always the same, regardless of how fast or slow the source or its observer is moving. The theory has as it consequences the relativistic mass increase of rapidly moving objects, time dilatation, and the principle of mass-energy equivalence which most people know by the equation E=mc2.

Special relativity supplanted Newtonian mechanics, yielding different results for very fast-moving objects. The Theory of Special Relativity is based on the idea that speed has an upper bound; nothing can pass the speed of light. The theory also states that time and distance measurements are not absolute but are instead relative to the observer's frame of reference. Space and time are viewed as aspects of a single phenomenon, called space-time. Energy and momentum are similarly linked. As a result, mass can be converted into huge amounts of energy, and vice versa, according to the formula E=mc. Albert Einstein devised the Theory of Special Relativity.

The special theory of relativity was proposed in 1905 by Albert Einstein in his article "On the Electrodynamics of Moving Bodies". Some three centuries earlier, Galileo's principle of relativity had stated that all uniform motion was relative, and that there was no absolute and well-defined state of rest; a person on the deck of a ship may be at rest in his opinion, but someone observing from the shore would say that he was moving. Einstein's theory combines Galilean relativity with the postulate that all observers will always measure the speed of light to be the same no matter what their state of uniform linear motion is.