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=__The Theory of Relativity__=

The theory of relativity affects society by means of black holes, the half life of particles, and cosmology. The Theory of Relativity is usually split into two parts.** Created by Einstein, The Special Theory of Relativity, based on Galileo's Theory states that the speed of light is the same for every observer, no matter their relative motion, and that the laws of nature are the same for all inertial frames. Later, Eintien continued and expanded this original theory and developed General Relativity. It states that all physical laws can be formulated so as to be valid for any observer, regardless of the observer's motion. Consequently, due to the equivalence of acceleration and gravitation, in an accelerated reference frame, observations are equivalent to those in a uniform gravitational field.
 * [[image:e-AlbertEinstein.jpg width="229" height="267"]]

Black Holes
One way that the theory relates to society today is through black holes. The theory shows us what happens if someone shines a light beam on a black hole, which is something that commonly occurs in space. The concept of a black hole is that when the light approaches the center, the person shining the light approaches the center even faster. An outgoing light beam shown on a black hole will move away from the person at exactly the same speed as the speed of light. No matter what the space-time may be, an observer will only see the lights beams in one direction at the same speed. This black hole example helps with the concept of the theory that nothing moves faster than light (Felder).

Half Life
The Theory of Relativity affects a certain concept of particles and clocks. Particle processes have an intrinsic clock that determines the half life of a decay process. However, the rate at which the clock ticks in a moving frame, as observed by a static observer, is slower than the rate of a static clock. Therefore, the half-life of a moving particles appears, to the static observer, to be increased by the factor gamma ("Theory: Special Relativity (SLAC VVC)"). This idea about the half life of particles proves the Theory of Relativity to be relavant to society today.

Cosmology
After Einstein came up with the theory of General Relativity, he and others found a way to apply it to cosmology. Cosmology is the study of the large scale structure of the universe. General Relativity predicts whether the universe is expanding or contracting. The theory shows that in some cases the space as a whole will contract and the distances between the stars will shrink. The universe could start out expanding, and depending on how fast it was expanding it might continue to do so or it might eventually stop and start contracting. It could never stay still, however (Felder). The concept of cosmology would not have been understood if it weren't for Einstein's theory.