I was thinking about Time Travel recently.

[ThinkAnarchy]

I came across this thread while searching the forum, but it didn't really cover the way I was thinking about it.

http://www.happyatheistforum.com/forum/index.php?topic=8659.0

First I want to ask some questions.

Would it be more likely that we would travel in our current form? Meaning, if I traveled back to the year I was three, would their be a three year old me and a current me walking around simultaneously? Or would it be possible for me to take the form I had at three?

I would imagine I would have to have two me's if I traveled back to a time where I already existed, but am not positive.

Now, if we could take our younger form, with the knowledge we currently have, we would all likely have similar goals. I would want to start becoming productive at an earlier age to build up enough capital to invest in google, or if it were possible build google, facebook, or another business before it ever existed.

If multiple people all wanted to beat each other to building Google or Facebook, I see no plausible way for that to work. It would seem you would need an infinite number of parallel universes and every time-traveler would have to live in his or her own.

Than it leads me to the question of what reality really is... It's a question I hate, because it simply leads to more questions. If I were given the option to be hooked up to a machine that converted my consciousness into a realistic virtual world, would the events that occur in that world be real? Or would my comatose body in this world be my reality? Would both planes of existence be my reality? Are things that happen in this virtual world real if they felt real and I believe them to be real?

Some of these may be easily refuted, I'm simply verbally shitting out my fingers...

Also, if I happend to travel farther in time and inadvertently kill one of my line before they had a chance to give birth to my great-great-great-great grandfather/mother, would I really cease to exist?

If there is only one line time can take than that would make sense. But are we sure their aren't multiple realities that branch out from our decisions?

If there is only one line for time and only one universe, it would seem to limit time travel only to going backwards. If we are living in the only present, there would seem to be no way to travel into that which doesn't yet exist.

On the other hand, if their are multiple universes playing out every possible choice anyone could ever make, traveling into the future would seem possible. At this point I'm getting into something that science may clearly suggest is not possible though. I have no clue.

I will stop here. I apologize if the above is not very clear, but I have to admit this line of thinking is out of my level of knowledge. I have no idea if I'm looking at the topic of time travel logically or illogically.

Any help people can give to help me better contemplate this subject would be greatly appreciated. Articles or books that target the non-scientifically inclined would likely be helpful too. I may try and read The Elegant Universe again. The last time I tried I was much younger and couldn't comprehend most of what I read and found it a bit boring. I might find it interesting and useful now if it doesn't require a strong understanding of scientific principles.

[Hector Valdez]

I don't think time is something that can be "traveled" through, per se. For example, if you move a box from point a to point b, and then move the box back to point a, how is that distinguished from harnessing a jigawatt of power and somehow magically changing existence to where the box is at point a? Wouldn't it be simpler to just move the box back?

Think about this: Negative acceleration can be applied to any object on a macro scale. Breaks slow cars down, etc. There's no real reason negative acceleration can't be applied to sub-atomic particles except current technological limitations. But if we advanced to the point where, we could apply a negative acceleration to all of the subatomic particles in, say, a tree, then there's no reason why that tree wouldn't "de-age".

Someone once said that time is what keeps everything from happening at once, but I disagree. I think space[/b] is what allows different things to happen at different times.

[Tank]

Conservation of momentum would fuck you completely. The Sun orbits the galactic centre every 200,000 years. If you jumped back to a time 100,000 years ago you'd be going in the wrong direction at 250km/s or 562,500 mph which would be mighty impressive if it wasn't for the fact the closing speed of the Earth would be equal and opposite! ie a relative velocity of over 1,120,000 mph!

[ThinkAnarchy]

Conservation of momentum would fuck you completely. The Sun orbits the galactic centre every 200,000 years. If you jumped back to a time 100,000 years ago you'd be going in the wrong direction at 250km/s or 562,500 mph which would be mighty impressive if it wasn't for the fact the closing speed of the Earth would be equal and opposite! ie a relative velocity of over 1,120,000 mph!

What if you went in small bursts of 5 years at a time? 

[Tank]

Conservation of momentum would fuck you completely. The Sun orbits the galactic centre every 200,000 years. If you jumped back to a time 100,000 years ago you'd be going in the wrong direction at 250km/s or 562,500 mph which would be mighty impressive if it wasn't for the fact the closing speed of the Earth would be equal and opposite! ie a relative velocity of over 1,120,000 mph!

What if you went in small bursts of 5 years at a time? 

Well you could limit your travel windows to every 200,000 years (or multiples there of) to mitigate the worst effects of this one issue. However the further you go back the greater the relative velocity of the galaxy in the local cluster and universal expansion. And if you go back in time you have to know where the Earth had to beat the time you are going to.

[ThinkAnarchy]

I don't think time is something that can be "traveled" through, per se. For example, if you move a box from point a to point b, and then move the box back to point a, how is that distinguished from harnessing a jigawatt of power and somehow magically changing existence to where the box is at point a? Wouldn't it be simpler to just move the box back?

Think about this: Negative acceleration can be applied to any object on a macro scale. Breaks slow cars down, etc. There's no real reason negative acceleration can't be applied to sub-atomic particles except current technological limitations. But if we advanced to the point where, we could apply a negative acceleration to all of the subatomic particles in, say, a tree, then there's no reason why that tree wouldn't "de-age".

Someone once said that time is what keeps everything from happening at once, but I disagree. I think space[/b] is what allows different things to happen at different times.

I will have to look more thoroughly at both space and time before fully being able to understand everything you just said.   It's a bit embarrassing how little I know about science...

As to your first example. It would seem do nothing to simply move the box back to it's previous point if you also wanted other aspects to remain the same when the box was previously at point A. The box would be moved to the same location it was in the past, but everything else could be different. If a lot of time had passed, it could be impossible to get the box in the same position with the same surroundings. I suppose it would depend on the reason for moving the box.

Space would seem to deal with the location of objects in a current time.

I understand what you are saying directly about negative acceleration, but am finding myself unable to apply it to time travel.

[ThinkAnarchy]

And if you go back in time you have to know where the Earth had to beat the time you are going to.

I apologize, but I'm really not following at that point. Are you referring to the earths rotation? And how points change through time?

[Tank]

And if you go back in time you have to know where the Earth had to beat the time you are going to.

I apologize, but I'm really not following at that point. Are you referring to the earths rotation? And how points change through time?

Our galaxy is moving towards the Andromeda galaxy. So irrespective of all the orbital issues (Earth's rotation, Earth's orbit, the Suns orbit of the galaxy) there is the additional issue of our galaxy itself moving through space. The Earth never ever passes through the some volume of space it has previously occupied and will never do so in the future. This has been the case for 4.5 billion years. So to get back to Earth in the past one would have to factor in all the relative movements to know where the Earth was in the past. I would contend this would be nigh on impossible.

[Hector Valdez]

Yeah, I'd say that'd fuck you pretty badly. Still, the point is that the sum total of all the relative positions in an environment determine the current "time".

[Unlinked]

This sort of thing is exactly what I've been pondering for the past three years or so for a story of mine. As far as I can see, there is no way to time travel via machine without encountering the possibility of paradoxes, forgetting all the information gathered in the future, or being able to change anything for anyone but the time traveler. At the end of it all, I basically ragequit the entire idea of a time machine and instead required time travelers to be 4-dimensional, or able to see and move in the "time" direction as well as the three spatial dimensions. Even this version of time travel requires a little hand-waving in order to be feasible, in that there's some vague reason why looking or moving into the future is impossible, but so far it's more solid than a time machine.

To bring information back in time, a time traveler goes through a time rift (which itself involves a long explanation but in short it is a ripple in the 4th dimension), which causes the time rift to "freeze" and the time traveler to revert completely to a younger period. It is as if they had never existed in the future. However, all the events that happened in the future, before the time traveler froze the time rift, is stored in that frozen rift, available as information for the time traveler to read when he or she can pop into the 4th dimension and take a look. Since time rifts can only last for a few months at most without causing the universe to snap in half (part of that long explanation), you couldn't really invent Google before somebody else, but you probably could make lots of money by leaking information on Apple's next new product a month or so in advance.

There is no way to travel back in time without the aid of the time rifts, so no time traveler can go back and kill their grandparents because there is no time rift that extends back that far. Time travelers also couldn't kill their younger selves because the laws of physics causes them to be immortal (in some way that I am also hand-waving) until someone else becomes 4-dimensional.

Coincidentally, this story also involves the issue of digital illusions that are indistinguishable from reality. In the story's society, illusions are treated as an extension of reality. Because while you are experiencing the illusion you have no possible way of telling that you are not actually seeing what you are seeing and doing what you are doing, you act as if the events in the illusion are indeed real. Therefore, any actions you take during an illusion are what you would do in a "real" situation. If you kill a bear with nothing but a sharp stick during an illusion, you would be capable of killing a bear with a sharp stick in real life and so you would be considered a badass. In the same way, if you commit mass genocide during an illusion, the authorities have reason to prevent you from entering politics or the army or whatever path allowed you the opportunity to do so. So technically, both reality and illusion are "reality" because both are testaments to a person's character and both have lasting consequences for the parties involved.

I hope this stimulates your thoughts a bit. I certainly had lots of fun coming up with these ideas and refining them over the years. I know I'm not that great at explaining the whole thing in one go, so if you have any questions, please ask.

[xSilverPhinx]

Reverse the resultant velocity and you'll get the opposite of entropy. That way you could "de-age".

They say that all times exist simultaneously though. Can't really get my head around that in the microscale we exist in. ???

Then there are those who say that the concept of time doesn't even exist outside the psychological. ???

Others say that entropy says that it does. ???

??? ??? ???

Reality...could turn out to be stranger than science fiction.

[OldGit]

How about if you only want to go back a couple of hours?  I just need to go back from Saturday 9.30 pm, after the National Lottery results are drawn, to before seven when I can still buy a ticket.  Not a lot to ask.

[xSilverPhinx]

How about if you only want to go back a couple of hours?  I just need to go back from Saturday 9.30 pm, after the National Lottery results are drawn, to before seven when I can still buy a ticket.  Not a lot to ask.

One more proof that time travellers probably don't exist, you would probably have the same people winning more than one time.

Either that or there are paradoxes that prevent that scenario...

???