Time Travel

[rcgreen]

My favorite treatment of this subject
will always be Dr Who.
Every episode explores the paradoxes,
possibilities, and the humor of it.

Einstein can't possibly be right, can he?

[Alcatraz]

Wizeman said:

I don't know if you've ever read the Michael Crichton "Timeline," but it is a story of time travel back to feudal times in France.

I read that book and liked it. It really would be cool to do the same time, except with a different era. Imagine the money you could make videotaping each era and selling it during modern times.

On a fictional note:

A scientist thinks he has invented a machine to take him far into the future. To be safe he attaches IV's to himself incase the trip sucks out nutrients or does something strange like that. But when he steps inside his machine and starts it, it instead causes him to fall into a coma for several months, and the IV's keep him alive during that time. When he recovers he discovers that yes, he has travelled in time and proclaims himself a hero.

This didn't really have a point but as chsh said, we're travelling in time as we speak. Or are we? We live in the present, so even if we were to travel back 1000 years then for us, it'd still be the present. No matter how far forward or backward you travel, you're still in the present.

[the_g_nee]

In order for you to be able to read this post, light is comming from a light bulb, or through the window, its then bouncing off the screen, and into your eye. Now more light is bouncing around than what you or I would be seeing at any one point in time - our eyes can only be in one place at a time. So this also happens, light is emmited from the light bulb, bounces off the screen, misses your eyes because they are not in the path of the light waves, passes through the window and carries on its trajectory maybe through our atmosphere and into outer space. Now if you were a few trillion miles from earth and had a very powerfull telescope, then you would be able to read my computer screen. My point is that the light that bounced off my screen will go on forever and ever.
Heres the going-back-in-time bit. Lets say you jump into your time travelling machine, which happens to be in my house next to the puter screen. And then start to accelerate on the same trajectory as the light which bounced of the screen and into outer space. Now you start to travel ever faster and faster - always staying on this trajectory. Now at a given point if you were to be travelling faster than the speed of light, what in effect you would be doing is catching up with light that left earlier and earlier in time, and therefore you would actually be travelling back in time.
Now I believe the theory goes that you would not have to travel in a constant straight line but you could go in a circle, or even spin, maybe even just shake, the only criteria is that you do so faster than the speed of light. Travelling faster than the speed of light = gong back in time. Though the theory on going forward in time....

***

chsh, I think that maybe your idea of travelling back in time to kill Hitler and thereby being in another dimension to this one is maybe wrong. As we know it today there is only one dimension - a 3D one - bredth width and height. There might well be 2D dimensions or even 8D dimensions, who knows, but if you could travel back in time you would be in the same dimension - a 3D one, would it not be the reality that had changed and not the dimension?

ps As soon as I build my faster than light time travelling machine, I'll post a new thread, cos it is simple in theory.

[Cheeseball]

Just for shear boredom purposes, let's say there is a flaw in the universe that allows traveling backwards in time. Let us say that yes, you can go back to WWII, cool....this is SOOO cool! Now...imagine you go back, kill hitler. My simple question is since you killed hitler before he caused mass genocide and in general a bad year for the world. Why would you (some years later) actually have a reason to go back and kill him? This is to say that the past must be written, in order to change it would result in a paradox. Just a thought and a conflict for classical views of time travel to consider.
Cheeseball

[angelic_ky]

i would change anything if i went back in time cos you don't know what the consequency will be.... besides, as i've said before, i believe everything happens for a reason

[chsh]

Originally posted by antihaxor
According to Einstien's Special Theory of Relativity time travel is possible. The details are found in his time dilation equation here: http://www.glenbrook.k12.il.us/gbssc...ity/u7l2a.html

I'm aware of his Special Theory of Relativity. If you check it out, you'll see he wasn't trying to say that you could travel backwards in time, he was saying that you would PERCEIVE you were travelling backwards in time.

This is the whole 'look at the clock while moving away from it at faster than the speed of light' analogy. You're not actually travelling backwards in time, you're merely perceiving that you are.

Besides, it's already been shown that the speed of light isn't a static limit and that it can be broken.

ADDENDUM:
Speed of light can be broken:
http://www.physics.utoronto.ca/~inte...ring/PAGE2.htm
http://www.compu-web.com/nimtz.htm
Speed of light is not a constant:
http://www.khouse.org/articles/techn...00701-265.html
http://www.npl.washington.edu/AV/altvw33.html

[chsh]

Originally posted by the_g_nee
chsh, I think that maybe your idea of travelling back in time to kill Hitler and thereby being in another dimension to this one is maybe wrong. As we know it today there is only one dimension - a 3D one - bredth width and height. There might well be 2D dimensions or even 8D dimensions, who knows, but if you could travel back in time you would be in the same dimension - a 3D one, would it not be the reality that had changed and not the dimension?

Perhaps 'dimension' was the wrong word. Perhaps something along the lines of 'parallel alternate universe' is a better descriptor.

[the_g_nee]

Great links in your post chsh!!

People go check them out right now!!

[hot_ice]

Imagine if someone actually discovered a way in which time travel is possible. Think about all the effects it would have. It would raise so many issues. People would straight away be wanting to goo back in time to fix this or kill these bad people or whatever. Others would be thinking what is ethical and should we change anything? What will the effects on our current state be?

I believe if we actually discovered a way to travel back in time, it would be one of the biggest disasters waiting to happen. What is it got into the wrong hands or someone altered something without carefully considering the after-effects? Changing something that we thought was bad, such as killing Hitler, might change the world in a negative way. I mean we simply view it as good - kill Hitler, save millions of lifes. But there are so many things that can happen as a result of this, things that we may not even begin to imagine.

Playing with the past, if we ever get the opportunity, is something that we shouldn't do. Just like angelic_ky said, everything happens for a reason.

Anyways, that's my two cents.

Greg

[rcgreen]

The same ethical issues are involved in
what you do in the present.
What you do today will control the
course of future history.