The Reality of Time Travel

"Time travel is theoretically impossible, but I wouldn't want to give it up as a plot gimmick."

— Isaac Asimov


So. Back to the Future. You know, the scene in the third movie where Marty complains they can't get the time machine to 88 mph because they'll run into a movie theater, and Doc says, "You're not thinking 4th dimensionally, Marty! When you go back to 1885, none of this will be here."

It's clever, cuz see, even though you're traveling to a different time, you're still in the same place. So while there's a movie theater in 1955, it's all prairieland in 1885. Where a bridge is under construction, 100 years later it'll be finished and you can just sail across.

But if you think about it, that's ridiculously Earth-centric.

See, during the time you skip, the Earth will have moved. For one thing, it rotates constantly. California (where the movies take place) moves through space at about 700 mph. So unless you are arriving at the exact same time of day as you left, the Earth will have shifted underneath you.

Pic by JasonParis, cc
In the DeLorean's inaugural voyage, Ein would've crashed into a house 12 miles west of the mall.
Also the Earth is traveling around the sun at about 67,000 mph. So not only would you have to arrive at the exact same time of day, but also the exact same time of year (we won't talk about that quarter of a day that makes Leap Day). So Einstein would have appeared somewhere past the International Space Station.

"Was that . . . a DeLorean?"

But that's assuming the sun is our central reference point, which is just as arbitrary. Why not use the galactic center? Or the (impossible to define) center of the universe? By some measurements, Earth is shooting through the universe at over 1 million miles per hour.

Poor Ein would end up a tenth of the way to the moon. And that's just for traveling one minute in to the future. Marty's first jump would land him somewhere past Neptune. His final 100-year trip would shoot him out of the solar system entirely.

Don't get me wrong, I love time travel stories. But writing them gives me a headache.

Who's not thinking 4th dimensionally now, Doc?

13 comments:

maine character said...

I tip my hat to you at 700+ mph.

Matthew MacNish said...

You just have to incorporate some m-theory, or an Einstein-Rosen bridge. Either that, or just ignore the whole spacetime continuum, and hope your readers won't care. Which they (obviously) often don't.

Susan Kaye Quinn said...

Hence why I fear time-travel stories. I keep telling myself I'll be brave enough to write one someday. Because even though readers will suspend their disbelief for long enough to read it, I have to live in the world long enough to write it. Which could make me insane. :)

I need stronger creative powers before I tackle such a mission. I'll put that out in Year 3 or 4 of the 5 Year Plan.

Charles Eubanks said...

Awesome. I wrote a story in jr. high history class that at least accounted for the earth's rotation. The MC met an eccentric fellow who was gathering flowers and crushing them in a mortar and pestle. Turned out to be Da Vinci, mixing his own pigments. BOOM!

Yeah, probably not as mind-blowing as my teenage self thought...

Cap'n Heine said...

This is why Dr. Who is interesting because there's (as far as I can tell) no explanation to the time travel or how they're changing any timelines or anything. They just keep visiting different times and places and stuff happens.

Nancy Thompson said...

I think the best way to combat the idea of time-travel is to not explain it. Just look at The Time Traveler's Wife. The MC had no idea how he traveled. That wasn't really the point anyway. It's what happened when he did. That was the story. And it was soooo good! Personally, I love time travel stories.

Peggy Eddleman said...

Sometimes I think it would be fun to live in your brain for a bit. :)

linda said...

Honestly, the space thing doesn't bother me anywhere near as much as the nonsensical treatment of timelines in the trilogy. Watched the whole thing recently and was greatly pissed off by all the stupidity.

But yeah, makes more sense if time machines are more like portals so you can only travel to/from a place/time where the time travel machine exists. Then traveling through space wouldn't be an issue since both are accounted for.

Angela Brown said...

Can I just stick with thinking 3 dimensionally and just hope for the best lol!!!

Sarah Ahiers said...

This is awesome. The good thing about fiction, is there's typically a way around the science

Myrna Foster said...

Can I just say how relieved I am NOT to have any time travel story ideas?

Heather Kelly said...

Thoroughly enjoyed this post. :) Came by way of the portal of Matt's blog. It's nice to meet you. :)

Deniz Bevan said...

The one thing I struggle with, ever since I read Diana Gabaldon's Outlander books, is how so many time travel stories assume that you can exist in the same time as yourself. That is, you can go back in time to where you already are. Physics-wise, it might not be possible...