Tourists of time all know one rule: never change the past. Whether it's preventing your own conception or handing the blueprints to a time machine to a younger version of yourself, generating a ...

Time feels like the most familiar thing in the world, yet it hides one of physics’ hardest questions: why do we only remember the past and never the future, and why do broken eggs not leap back into ...

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 ...

For those who watch gravitational waves roll in from the universe, GW250114 is a big one. It's the clearest gravitational ...