General relativity (GR) is the geometrical theory of gravitation published by Albert Einstein in 1916. It unifies Einstein's earlier special relativity with Sir Isaac Newton's law of universal ...

Albert Einstein's general theory of relativity is one of the towering achievements of 20th-century physics. In our introduction to general relativity, we explain how this theory developed, plus how it ...

When the theory of relativity appeared in the early 1900s, it upended centuries of science and gave physicists a new understanding of space and time. Isaac Newton saw space and time as fixed, but in ...