Ultimate Geek Fu

 
It's About Time.

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We did better than usual with Terminator Salvation. This time we almost made it back out to the parking lot before The Kid said, "Dad? There's just one thing I don't get. If they killed off Miles Dyson and blew up Cyberdyne in Terminator 2, which changed history, and this is a completely different timeline with a completely different SkyNet, how come this version of SkyNet knows what the SkyNet in the first two movies did?" He frowned after he asked me this, but before I could attempt to answer, he added, "And one more thing—"

By the time we'd made it back to the car, he'd one-more-thinged his way all the way around to, "And if wiping the Connors out of existence is so blasted important, why does SkyNet bother with all these piddly little attempts in the first place? Why doesn't it send a bunch of Arnolds back to Germany in the 1930s to try to change who won World War II?"

Hmm. Maybe it did.

As sci-fi writers, this is one of the biggest cans of Instant Headache we can open: the causality paradox. Time-travel is one of the hoary old tropes of the form, so we can't resist the temptation to use it, but if we could travel through time we might change something, and if we changed something dramatically enough we might change ourselves right out of existence, so therefore we wouldn't exist to travel back in time to cause the change in the first place, so therefore—

Ow! Must make brain stop hurting!

When we start talking about this topic the story everyone thinks of is Ray Bradbury's classic, "A Sound of Thunder", which I love if only because it was the inspiration for a particularly brilliant Simpson's episode, but the truth is that the literature and filmography of sci-fi is just loaded with time-travelers casually playing hob with causality and playing silly buggers with history, from Dr. Who and Mr. Peabody and that bunch of dwarves with the stolen map to one of my sneaky little sentimental favorites, Time After Time— and of course, there's always Ahnold and his ilk.

So, how about it? What's your favorite time-travel story or movie? What's the coolest gimmick or cleverest plot device you've seen or read that pertains to time travel? And what is the one time-travel story, TV show, or movie that absolutely gives you a whanging headache every time you try to wrap your mind around it and force it to make some kind of sense?

Let the arguments begin.

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ULTIMAGE GEEK FU runs every Wednesday. Have a question that's just bugging the heck out of you about Star Wars, Star Trek, Stargate, Battlestar Gallactica, Farscape, Firefly, Fringe, Heroes, The Sarah Connor Chronicles, Smallville, The X-Files, X-Men, The Man From Atlantis, or pretty much any other SF-flavored media property? Send it to slushpile@thefridaychallenge.com with the subject line, "Geek Fu," and we'll stuff it in the queue.