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__ Theory of relativity and special theory __

The theory of relativity stands out as one of the greatest achievements in science. The “special theory”, which did not include gravity, was put forward by Einstein in 1905 to explain many troubling facts that had arisen in the study of electricity and magnetism. In particular, his postulate that the speed of light in vacuum is the same constant seen by all observers forced scientists to throw away many closely held commonsense assumptions, such as the absolute nature of the passage of time. In short, the theory of relativity challenges our notions of what reality is, and this is one of the reasons why the theory is so interesting. Einstein published the “general” theory of relativity, which is a theory about gravity, about a decade later. This theory is far more mathematically daunting, and perhaps this is why it took Einstein so long to come up with it. This theory is more fundamental than the special theory of relativity; it is a theory of space and time itself, and it not only describes, it explains gravity. Gravity is the distortion of the structure of spacetime as caused by the presence of matter and energy, while the paths followed by matter and energy (think of bending of passing light rays by the sun) in spacetime are governed by the structure of spacetime. This great feedback loop is described by Einstein’s field equations.

This is a about general relativity. There is no getting around the fact

that general relativity is mathematically challenging, so we cannot hope to learn the theory without mastering the mathematics. Our hope with this is to “demystify” that mathematics so that relativity is easier to learn and more accessible to a wider audience than ever before. In this article we will skip any of the math that relativity requires, but we will present it in what we hope to be a clear fashion and illustrate how to use it with many explicitly solved examples. Our goal is to make relativity more accessible to everyone.

that general relativity is mathematically challenging, so we cannot hope to learn the theory without mastering the mathematics. Our hope with this is to “demystify” that mathematics so that relativity is easier to learn and more accessible to a wider audience than ever before. In this article we will skip any of the math that relativity requires, but we will present it in what we hope to be a clear fashion and illustrate how to use it with many explicitly solved examples. Our goal is to make relativity more accessible to everyone.

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