ANSWERS: 1
-
Well...such paradoxes in fiction typically have one of two (rather reasonable) resolutions. #1 - Multiple time lines. The future that the soldiers fought and died in really happened, but a separate time line was established AFTER that happened, from the point of view of the present, in which no such war occurred. Thus, the soldiers died in ***what is now*** an alternate time line future that will never happen. #2 - Inevitability (or: one time line, what has occurred and what will occur cannot be altered). In fact the hero did NOT manage to kill all of the aliens. Either he missed some frozen ones, or more of them came to Earth after he killed them (in the future). In this scenario, the future war still occurs in the future and the hero didn't really solve the future crisis.
Copyright 2023, Wired Ivy, LLC