We all have some past events that we'd like to undo. These can be minor moments, such as a failed exam or an argument with friends, or world-changing incidents, such as the 2019 outbreak that led to ...

Time travel has long been a favorite idea in science fiction. Stories about changing the past or visiting the future have captured imaginations for generations. While building a real time machine ...

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

JUDY WOODRUFF: But, first, this week marks the 100th anniversary of the publication of Albert Einstein’s greatest work, a series of papers laying out the general theory of relativity. Gwen has a look ...