110 years ago today, Albert Einstein published his General Theory of Relativity, which redefined the relationship between matter and gravity. Suddenly, our mysterious universe made a little more sense ...

Tachyons are a hypothetical particle generally thought to be incongruous with Einstein's theory. New measurements from an experiment near the top of an extinct Mexican volcano have placed a stringent ...

Proposals offering alternatives to Einstein’s relativistic theory of gravitation are almost as old as the theory itself. Einstein even saw them as the beginning of a path that could lead to quantum ...

This is an example of time dilation, a consequence of the idea that time and space are not absolute - meaning all observers do not always measure these quantities as the same. In everyday life we use ...