IntroductionEinstein's theory of relativity is a famous theory, but it is 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 then was considered a special case of the more complete theory of general relativity. In the 19th century, scientists believed that light was a wave. They believed that light waves needed a medium to travel, which is why they invented the concept of “aether.” Light was thought to transmit through the ether, which remains still while all matter passes 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, a beam of light took a path against the ether and back while the the other was perpendicular to the ether. Michelson and Morley expected to calculate the Earth's speed through the ether; to their surprise, the beams of light completed the journey at the same time. However, the famous Michelson-Morley experiment had failed to detect the motion of the Earth relative to the ether and no one could explain why. Something was wrong with the traditional understanding of relativity as it applied to light. In this essay, we will explain in more detail the two parts of the theory of relativity and their relevance to our world. The theory of special relativity It was not 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 ​​the ether is not necessary if one expects the speed of light is an absolute constant...... middle of paper ...... uh. This example shows that space and time are interconnected. Furthermore, Einstein was able to show that mass and energy were linked, with the legendary formula E=mc2. Basically, Einstein discovered that object mass increased as an object approached the speed of light, i.e. The object therefore goes faster, but it also becomes heavier. If it were actually capable of moving at c, the mass and energy of the object would both be infinite. A heavier object is more difficult to accelerate, so it is impossible to bring the particle to a speed of c. This relationship was most dramatically proven to the world when nuclear bombs unleashed mass energy in Hiroshima and Nagasaki at the end of World War II. The theory of special relativity is so “special” because it is part of the more complex and larger theory. of General Relativity, which reshaped the world of physics.