Scientists, or at least their wild-haired fictional counterparts, promised us time travel and still have not delivered. Forget walking with dinosaurs or killing baby Hitler; I’d be happy just to warn my month-ago self not to make all the mistakes he’s about to. It’d also be nice to zoom past the next few months (year? years??) to the nationwide orgy of the post-virus era. Of course, none of these things are possible, because time travel doesn’t exist. But could it? That is the subject of this week’s Giz Asks, for which we reached out to a number of physicists.
One obvious point to start with is that time travel works already. We’re all caught in the river of time, traveling inexorably into the future. A person or object can move freely in any direction through the spatial dimensions, yet time is directional. Despite these differences, space and time are inextricably linked into the four-dimensional concept of space-time, as formulated by Einstein over a century ago in his theory of “special relativity.”