Time Travelers, Please Proceed to Gate Number 42

Last night while watching Hiro Nakamura and Nathan Petrelli doing their thing on Heroes, I came to the conclusion that strolling through the forth dimension is much more fun than flying through the other three. While time traveling seems like a great way to spend your weekends, is it feasible?

Forward time traveling is relatively simple. It can be achieved by accelerating to extremely high speed or by getting close to an extremely big mass. As predicted by Einstein’s theory of relativity - time is subjective. For example, you can go on a one minute high speed trip only to return to Earth to discover you have just missed a whole decade back at home. A real-life example is the cosmonaut Sergei Avdeyev that spent a total of 748 days on the Russian space station Mir and missed a whole 0.02 seconds on Earth.

Although that DeLorean looked really cool on Marty McFly, backward time traveling may be theoretically or practically impossible. Some claim it can be done using wormholes, black holes or other abnormalities of spacetime, while others claim it exists only in science fiction.

If backward time traveling is possible, where are all the tourists from the future? Even if it will be illegal in the future to go back to the past, I’m sure some would break the law eventually.
Possible explanations are:
1. Backward time travel is not possible.
2. It’s theoretically possible but practically impossible.
3. It can be done, but we will destroy ourselves before achieving this.
4. It will be done in the future, but time machines allow you only to go back as far as the time the machine was created.

A famous problem is the grandfather paradox, where a man travels back in time and kills his own grandfather before the latter met the traveler's grandmother. As a result of this act, the traveler could not have been born, so how can he later travel back in time? Some see this paradox as a death blow to backward time travel possibility, but although definitely weird, I think the only problem here is that it’s not aligned with our intuition. Because human logic was developed by evolutionary process in order to better hide from lions and hunt zebras more effectively, I don’t see a big problem in the fact that 21st century thought experiments regarding traveling through the forth dimension don’t appear logical to us hunter-gatherers.

No need to comment on this post since I have just been back from the future and already read all your comments.

p.s. Every time a lightning hits the Eiffel Tower there’s a 78% chance your wife’s on the phone.


rlowe1980 said...

the concept of parallel dimensions/realities solves the grandfather paradox..

so, killing your grandfather wont effect your reality..

so dont worry about your hand disappearing while playing your guitar.. :-)

Uri Kalish said...

I have a problem with the parallel universes idea.

rlowe1980 said...

I understand.. parallel universe idea does sound hokey-pokey and far fetched.

but it's like "God" theory. so far, it cant be disproved.. unless you know something i dont about it... if you do, let me know..

Falls-Down-Laughing said...

Hey, here's a wacky thought - go back in time to when a Egyptian mummy was buried (one we know has now been found and studied, of course), get involved in the mummification, and leave a Euro coin (or another such anachronismic item of utter bafflement) just under the wrappings! Wouldn't that eventually be a hoot! ahahaha :P ^_~