So the new Star Trek movie that opens today is completely predicated on one very popular theory of time travel, which holds that by going back into the past we inevitably change the present that we’ve left behind. This means that time travelers can abandon any dreams of clean, no strings attached time travel, because they are in fact creating a new reality (a perfect reality in which to build a new movie franchise, for instance).

Of course, looking back through Star Trek mythology you start to realize that the epic space-western series is rather promiscuous with its time travel theories. In fact, io9 has found some 6 Theories of Time Travel from Star Trek that will give all you aspiring time tourists something to think about before you go jumping through any black holes.