1 {scene: the Legacy engine room}
1 Spanners: We've travelled back in time and messed up history. I speculate that this fissure in time is the universe's way of healing itself.
2 Spanners: We go through it, history is restored, and we return to our rightful time.
3 Quercus: But if it's a wound in the universe and we fly through it, won't we end up outside the universe?
4 Spanners: That'd also be pretty cool.

I guess if the universe can be wounded, it needs giant space-amoeba-like white cells to travel around and heal them up.

Well, that's the best explanation I can think of for the Star Trek episode "The Immunity Syndrome".