SPOCK: You are assuming that Nero knows how events are predicted to unfold. To the contrary, Nero's very presence has altered the flow of history, beginning with the attack on the USS Kelvin, culminating in the events of today, thereby creating an entire new chain of incidents that cannot be anticipated by either party.
UHURA: An alternate reality?
SPOCK: Precisely. Whatever our lives might have been, if the time continuum was disrupted, our destinies have changed. Mr. Sulu, plot a course to the Laurentian system warp factor three