Albert Einstein's general theory of relativity describes gravity as the warping of space-time geometry by mass, a concept distinct from Isaac Newton's absolute space and time, and has been empirically ...

When speaking of our universe, it's often said that "matter tells spacetime how to curve, and curved spacetime tells matter how to move." This is the essence of Albert Einstein's famous general theory ...

After some serious number crunching, a researcher says that he has come up with a mathematical model for a viable time machine: a Traversable Acausal Retrograde Domain in Space-time (TARDIS). He ...