Spock: In order to return us to the exact moment at which we left the twenty-third century, I have used our journey back through time as a reference, calculating the coefficient of elapsed time in relation to the acceleration curve.
Bones: Naturally. So what’s your problem?
Spock: Acceleration is no longer a constant.
Bones: Well, then you’re gonna have to take your best shot.
Spock: Best shot?
Bones: Guess, Spock. Your best guess.
Spock: Guessing is not in my nature, doctor.