I love the new Star Trek reboot. It’s really fun. It does mess some things up time-travel-wise, though. Specifically, how does it fit in to Star Trek canon given the presence of the original Enterprise team in the past? While there is a lot of time travel, for simplicity’s sake I’m going to focus on Star Trek IV: The Voyage Home.
In Star Trek IV, the Enterprise bridge crew travel back to 1986 in the HMS Bounty to bring extinct humpback whales into the future to save the Earth from a probe sent by alien whales wondering what’s happened to their colonists. They pick up a couple whales and return to the future in time to save the Earth. Then in their future (in the Star Trek reboot), Spock and Nero travel back in time and start an alternate timeline.
Presumably, those alien whales are still out there and still send the probe. So, when presented with the same problem of needing whales from the past, presumably the new Enterprise crew (or someone else from the new reality) will attempt the same thing of travelling back to 1986. While in the past, do they encounter the original Enterprise crew? After all, the old Spock is testament to the fact that the original timeline did indeed happen, just that it’s currently out of reach if he were to go into the future. Old Spock had a past and in that past, he participated in a jaunt backwards in time to before the incident that spawns a vastly alternate timeline, so presumably that jaunt still exists in the history of the new timeline.
So, now that we’ve got new and old crews together, what happens in the return to the future? Would the old crew return to the old reality? That seems to make sense given that old Spock’s past would need to be retained. But what about the new crew? Would they go into their reality? That also makes sense given that the original Spock creates the new reality after returning to his future. But, wait, they go into two separate futures? Does that make sense?
Okay, suppose the new Enterprise crew hitches a ride on the HMS Bounty. Do they go to the old reality together? That doesn’t make any sense, but going to the new reality together doesn’t make any sense either. I think J. J. Abrams worked himself into a paradox on that one. Though, technically, the whole Star Trek IV premise is based around whales building spaceships, so Star Trek’s time travel problem is already unrealistic.