Technically the multiverse should have a shared past - if the nuTrek crew went back to 1986 they should bump into ShatnerKirk and NimoySpock saving the Whales. If they go back to 2064 they'll meet Riker and Geordi. If they go back to 2002 they'll find Archer, T'Pol, Xindi and a bunch of hookers. If they go back to 1996 they'll meet Captain Janeway and crazy Braxton. If they go back to 2151-2155 they'll watch episodes of Enterprise (let's hope they skip the first two seasons!) and so on.
Interesting. I always thought a lot of those other time travel events were more of a predestination paradox, and I'm not sure how they could be reconciled with the multiverse concept.
Data’s head must be a predestination paradox, but in the case of transparent aluminum, there is another possible explanation that I think is kind of fun:
In the “original” timeline, Dr. Nichols discovers the formula for transparent aluminum. Then McCoy and Scotty go back in time and give him the formula shortly before he was going to discover it for himself. The rest of history unfolds pretty much the same way, except Dr. Nichols’ conscience is troubled. He thinks he got the formula from two mysterious strangers who appeared out of nowhere with bogus identities, traded the formula for a giant water tank, and were never heard from again. He feels guilty about passing it off as his own work and has no idea that it really is his own.