Some ideas are:
- You branch off into another timeline and your actions make no difference to the previous timeline
- You’ve already taken said actions but just didn’t know about it so nothing changes
- Actions taken can have an effect (so you could suddenly erase yourself if you killed your parents)
- Only “nexus” or fixed events really matter, the timeline will sort itself out for minor changes
- something else entirely
Time travel to the future is possible if you travel fast enough. For example, traveling to the nearest galaxy at near-light speed wouldn’t take long for you, though it would take significantly longer for those observing you from Earth.
As for traveling to the past, I imagine it might involve the many-worlds interpretation of quantum physics, where every possible event that can happen does happen in a separate timeline. In this view, you wouldn’t be “changing” the past but rather experiencing an alternate version of it.
I don’t believe in free will, so I’m not concerned about the idea of altering the future by changing the past. If you traveled back in time and killed Hitler, it wouldn’t affect this timeline’s future; instead, you’d simply enter a timeline where that event occurred. The future of your original timeline would remain unchanged.
Travelling to the future is so easy that you can’t not do it