Ask Ethan: Would Traveling Back In Time Destroy The Universe?
“My 8 year old watched the Back to the Future movies for the first time and would like to know if, as Doc Brown suggests, the creation of a temporal paradox could unravel the space-time continuum and destroy the entire universe?”
Whenever someone attempts to travel back in time in any science-fiction setting, they’re always warned against messing with the timeline and making drastic changes. The reason? If you alter the past, you have a chance of changing the present in some dramatic ways, potentially in ways that would even prevent your own existence, or the possibility of events that have already occurred. But that’s normally the entire motivation for traveling back in time, from 12 Monkeys to Terminator to Back to the Future. Yet there might be not just one, but two possible ways out. Traveling back in time and changing the past may or may not be physically possible, but if it is, it might lead to a new present that’s just fine in terms of the Universe’s stability, no matter what it is you do.