Logic question

for those of you who have not yet seen Star Trek, stop reading and go see it!




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for those of you who have, i have a question about the movie.....

why is it that when the romulan ship and spock (from the future) go through the black hole, they go back in time, and when the vulcan planet goes through the black hole, they are destroyed forever?

other than this logical conundrum, it is a fabulous movie - i cried when kirk the father sacrificed himself in the first 5 minutes of the movie! and i thought kirk the son was the dad from august rush, but he is not. i actually thought he was not as good-looking or as heart-throbby as others might... because bad boys are not worth the trouble, ladies!!! sylar as spock was great casting, but kinda creepy. i kept expecting him to slice someone's forehead open.