# Special and General Relativity Essay

explanatory Essay
797 words
797 words

Introduction
Einstein's theory of relativity is a famous theory, but it's little understood. Essentially, the theory of relativity refers to two different parts of the same theory: special relativity and general relativity. The theory of special relativity was introduced first, and was later considered to be a special case of the more comprehensive theory of general relativity. During the nineteenth century, scientists believed that light is a wave. They reasoned that waves of light need a medium to travel through, so they invented the concept of "ether." Light was thought to transmit through the ether, which stands still while all matter moves through it. In order to measure the earth's speed through the ether, Albert A. Michelson and Edward Morley collaborated on an experiment in 1887. In the experiment, one beam of light took a route against the ether and back while the other was perpendicular to the ether. Michelson and Morley expected to calculate the speed of the earth through the ether, to their surprise, the beams of light completed the course in the same time. However, the well-known Michelson-Morley experiment had failed to detect Earth's motion relative to the ether and no one could explain why. Something was wrong with the traditional understanding of relativity as it applied to light. Within this essay we will further explain both parts of the theory of relativity and their relevance in our world.
The Special Theory of Relativity
It wasn't until 1905, that the results of the Michelson-Morley experiment were explained. In Einstein’s most famous scientific paper, On the Electrodynamics of Moving Bodies, Einstein clarified that the idea of ether is unnecessary if the speed of light were expected to be an absolute const...

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...ers. This example shows that space and time are interconnected.
In addition, Einstein was able to show that mass and energy were related, with the legendary formula E=mc2. Basically, Einstein found that the mass of the object increased as an object approached the speed of light, c. Therefore the object goes faster, but it also gets heavier. If it were actually able to move at c, the object’s mass and energy would both be infinite. A heavier object is harder to speed up, so it’s impossible to ever actually get the particle up to a speed of c. This relationship was proven most dramatically to the world when nuclear bombs released the energy of mass in Hiroshima and Nagasaki at the end of World War II.
The Special Theory of Relativity is so ‘special’ because it is part of the more complex and extensive Theory of General Relativity, which reshaped the world of physics.

#### In this essay, the author

• Explains einstein's theory of relativity, which refers to two different parts of the same theory.
• Introduces the special theory of relativity, which explains how to interpret motion between different inertial frames of reference.
• Explains einstein's theory based on two postulates: the first one states that all physical laws are the same in every inertial frame of reference, and the second one is that the speed of light is constant.