The problem with time travel…
Life, Science 05/05/2005 |Yes, the problem. Because there is only one. 
I don’t even remember how we got on the subject, but something in a conversation with Prairie last night got me rambling on about the biggest problem I have with time travel stories. As fun as they are, there’s always been one thing that bugged me about them — though, admittedly, it’s most likely because in the majority of instances, worrying about it would essentialy negate the possibility of the story working at all.
Essentially, it’s that while what makes the story fun is the ability to travel temporally, nobody ever seems to take into account the need to travel spatially as well.
The Earth rotates at a little over 1000 miles per hour. It also orbits the sun at around 67,000 miles per hour. Our solar system is moving through the galaxy at approximately 447,387 miles per hour. Our galaxy is moving at roughly 1.34 million miles an hour through the universe. So, assuming that those are all the variables we have to work with (that is, assuming that time is a constant within our universe, and that there is nothing “outside” our universe to measure its relative speed), we travel (very) roughly 6,679,393,200 miles per second relative to our universe.
So, were I to invent a time machine and move myself one second back in time, I’d end up popping back into the normal time stream somewhere more than six and a half billion miles away from where I started! Needless to say, I’d be incalculably lucky to end up arriving anywhere that would allow me to survive — most likely, I’d just end up floating out in the vacuum of space somewhere.
Any feasible time machine, then, would somehow have to ensure that the traveller was able to move temporally while remaining stationary spatially relative to their starting point, and not to the universe as a whole.
Tricky.
Not that that keeps me from enjoying time travel stories anyway, of course. But there’s always this niggling little voice in the back of my head…
“Discotheque (Howie B, Hairy B)” by U2 from the album Discotheque (1997, 7:40).
[See also: So Long, Space Needle | More on Animatrix | Neil Gaiman’s ‘Goliath’ | Jupiter | Mars needs a facelift! ]
5 Responses to “The problem with time travel…”
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Cheryl
Bertamum
Michael Hanscom
Snail_5
Bob
May 5th, 2005 at 9:18 pm
My problem with time travel is that it is completely useless. No matter how hard you try, you can never actually accomplish anything. Suppose that you went back in time to save someone’s life. If you managed to succeed, then that person would (from your future POV) not have needed saving, and so you wouldn’t have gone back in time, which means they wouldn’t have been saved which means they would have needed saving which means you would have gone back in time…
I think Invader Zim solved this little problem quite nicely by causing Gir’s (the character having this argument) head to explode.
May 5th, 2005 at 9:52 pm
Dr Who had this sussed out 30 years ago: the TARDIS (time and relative dimensions in space) managed the other three dimensions as well.
May 5th, 2005 at 11:02 pm
“Ford,” he said. “You’re turning into a penguin. Stop it.”
May 6th, 2005 at 7:39 am
All those topics where covered in a recent slashdot discussion.
What you were talking about brings another problem:inertia. Maybe we could arrange things so that you could appear in the same (relative) position on earth, but… where could the energy come so that you move with the same speed? The earth is in motion, you not, so you’ll end crushed or throwed away from it.
Another interesting reading is this article in the Wikipedia.
May 6th, 2005 at 2:43 pm
As long as we’re on the topic I think you should check out “Primer.” http://www.imdb.com/title/tt0390384/
It is not the absolute best movie I have ever seen but for a rumored $7000 to make it is the best cheap movie I have ever seen.