>>11888205There are many reason why time travel is a trope of fantasy, and not science fiction.
For example, if it were possible to time travel to the past, that would imply that a snapshot copy of the entire universe was somehow being created every attosecond, otherwise it wouldn't be possible to travel back to any arbitrary moment. Where do you suppose thhese copies reside? Where would the mass and energy for them come from? How is special relativity accounted for? Suppose two time travelers are one light-year apart and each travels back one year; would each traveller's changes to history propagate toward the other at the speed of light? What happens when these "light cones" collide? Could they each prevent a radio transmission that had previously given the other traveler the plans for a time machine?
