Time travel has shifted from pure fantasy to a serious, if highly constrained, topic in modern physics. The equations that describe gravity, quantum fields and the structure of spacetime now allow ...

The curious minds at What If examine overwriting Einstein’s theory of relativity with time travel, imagining paradoxes, causality, and cosmic consequences.

Like stretch marks left on skin that expanded too quickly or cracks embedded in freezing ice, cosmic strings are artifacts of ...

A trip through time has always sparked curiosity. The idea that you could step into a machine and emerge in the past or future has captured human imagination for generations. While science fiction ...