What is special relativity?
Q: What is special relativity?
A: Special relativity (or the special theory of relativity) is a theory in physics that was developed and explained by Albert Einstein in 1905. It applies to all physical phenomena, so long as gravitation is not significant. Special relativity applies to Minkowski space, or "flat spacetime" (phenomena which are not influenced by gravitation).
Q: What weaknesses did older physics have?
A: Older physics thought light moved in luminiferous aether and various tiny effects were expected if this theory were true. Gradually it seemed these predictions were not going to work out.
Q: What conclusion did Einstein draw?
A: Einstein drew the conclusion that the concepts of space and time needed a fundamental revision, which resulted in special relativity theory.
Q: What was Galileo's principle of relativity?
A: Galileo's principle of relativity said that physical events must look the same to all observers, and no observer has the "right" way to look at the things studied by physics. For example, the Earth is moving very fast around the Sun, but we do not notice it because we are moving with the Earth at the same speed; therefore, from our point of view, the Earth is at rest.
Q: How did Galileo's math fail to explain certain things?
A: According to Galileo's math,the measured speed of light should be different for different speeds of the observer in comparison with its source; however, this was disproven by Michelson-Morley experiment.
Q: How did Einstein explain this phenomenon?
A: Einstein's theory of special relativity explained this among other things by establishing a new principle "the constancy of speed of light" combined with previously established "principle of relativity".
