Time travel is theoretically possible, new calculations show. But that doesn’t mean you could change the past

Doc Brown and Marty McFly in “Back to the Future.” Screenshot

  • Time travel is possible based on the laws of physics, according to new calculations from researchers at the University of Queensland.

  • But time-travelers wouldn’t be able to alter the past in a measurable way, they say — the future would stay the same. 

Imagine you could hop into a time machine, press a button, and journey back to 2019, before the new coronavirus made the leap from animals to humans.  

What if you could find and isolate patient zero? Theoretically, the pandemic wouldn’t happen, right? 

Not quite, because then future-you wouldn’t have decided to time travel in the first place.