This is kind of science, kind of philosophy.

My thoughts are this:

The idea of time travel is a fallacy of linear thought. Time isn't linear, because the only thing that actually exists is NOW. The future hasn't happened yet, the past is done with (and once something has happened, its GONE baby!). So time is more like a single point traveling through something. Then again, maybe it doesn't even have to travel. Maybe time travels through IT. Either way, nothing else exists but the moment.

Even if you could go back in time, you couldn't change anything. Again, it would've already happened, thus getting rid of the reason that you would've gone back in the first place, meaning you would never have gone back, meaning that it wasn't changed. Rather chicken-and-the-egg-ish, isn't it?

Some crazy stuff. I had to talk myself out of a few circles to figure out what I was trying to say a couple of times. So am I nuts? Probably. But what do you think?

first, don't necessarily denote time as linear....please visit the "infinity" thread....

anywho, it is in my thoughts that physical existence is linear.....metaphysical existence is circular....

thus, it could be possible to travel in time through some sort of metaphysical sense....as seems evident with QUOTE-UN-QUOTE past lives or seeing into the future (such as Nostradamus....or what have you).....even "deja-vu" would be an example of this.....

i do not believe in time travel, specifically when related to physical existence......if i'm not mistaken, scientists thought that "black holes" could prove to be a source of time travel....yet, just this year Stephen Hawking announced that his theory of time travel via the black hole now seems improbable, as the theory of black holes as they understood it (something with such a graviational force that nothing can escape it) proved to be false, and now they suspect that the black holes actually spit forth some matter out into space....

anywho....there's a couple of lil' problems you didn't think thoroughly through....for starters, you couldn't really go into the past....at least, not beyond the point prior to the time machine being built......

also, the only thhing that "exists" isn't now......you didn't clarify these terms.....you should have said, the only that exists when concerning linear time is now....but even then, thatz incorrect, as the past exists just the same.....although we are within the now, that doesn't mean yesterday didn't exist......and although there isn't a full 100% chance that tomorrow will come, it is still a high enough probability (99.9999999999%) that it will, so it exists just the same....

i believe it was Hume who mentioned some of this....i'm not 100% sure, but i think it was Hume.....he sort of touched on the theory of destiny, which he also spoke briefely about time (in a round about way)......he basically explained it as a sort of reverse-destiny...

take a choice...say, going to work.....you have the choice to go to work or not go to work....right?

wrong......granted free-will seeminly does exist (and i'm not quite sure whether Hume believed in free-will or not, but i think he did) it was in his theory that whatever choice you make you couldn't have done the other......if you go to work, then you go to work.....you never had the choice to not go to work, becasue you went to work.....if you didn't go to work, you didn't go to work....you never had the choice to go to work, because you didn't go to work...

i know it sounds rather confusing, but he explains it a lot better than i can.....anywho, to get to the point, he also touched somewhat on time....and the best analogy i can use, is when you're in a car...

you're in a car, going down the highway.....the past, is the road behind you, the present is where you're physically at at the present moment, and the future is the car in front of you......all three exist, yet you seem stationed in the present.....however, itz almost a trick....as you know that at some point in time you will be where the car is at in front of you, and then at some point in time that spot will be behind you.....all three do exist....

Time
What is time?
Thats what many scientist asked themself.

It's kinda hard to explain,but i'll keep it simple;
Time contains 3 part:past,present and future,what i believe is there would be no future without the past and there would be no past without the future.
The present(now) wouldn't have a purpose if there was no future or past.

So both past and future do/still exist to maintain eachother.

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I think the major point of time travel (and why some scientists are obessed with) is to change the past so it would change the present and the future.
The real question is, can we change the past?

for example;If a time traveler goes back in time and kill his grandfather (before time travelers is born),does that mean the time traveler will just dissapear when he gets back in his own time or nothing will change and creates two dimensions?

Time travel is happening now... we are moving forward in time at a rate of one second per second.

why would he want to?

Just an example,or maybe he didn't like his christmas present.

That's a good point about crappy Christmas presents.

However

everything in the past has already happened. Therefore if your time-traveller went back to kill his grandfather then he would fail because he must have already failed otherwise he wouldn't exist to go back. Or maybe the person he thought was his grandfather was in fact an adoptive parent or maybe his grandmother was a bit of an old slapper and shared it around a bit. Meaning he killed the wrong person.

I didn't say time was linear...I said it wasn't, and the problem is that many seem to view it as such. I disagree with the highway example because I don't think that time operates in that way. I don't think we actually have the capacity to grasp how it works, so we visualize it as linear because that establishes some sort of familiarity, although that visualization is probably not true at all.

does time exsist?

there can never be a present becuase as soon as you say such, it is already the future and now when you said thatm it was the past.

The present is right NOW... but the moment has already expired.. becuase of how you measure time... seconds and be cut down and mili-seconds can be, and so on and so forth... so it's like an infinate, and since there is no end point on an infinate then how can there be a present... time exsists only in our heads, like this writing it is only thought.

There are probably a lot of things wrong with what I have said, but I'm curious to hear them.

Time is foolish in that it's relative to mass and velocity.

You can't measure time,you don't know when the past started and you don't know when the future ends
Present is the one that divide past and future from between (like a membrane)

It's function is to build up past and future,you can say it's using every event (every little detail) of the past to build up in into the future.

another thing to think about if you do go back you half to go back EXACTLY 1 year becouse you might end up in an ocean or open space or halfway between a wall. and i do think that it would cuase alternet demensions UNLESS it was not the first time it was done.

you couldnt change the orginal timeline but you could create another.

time is linear it begins and ends

Jim

Self is one of the belivers in a Multiverse = Multiple timelines being traveled at diffent varibles simataiously etc. Self belives time travel is possible but hard to prove our minds travel bnack and forward all the time or do we just link info from faster or slower self's traveling in different lines yet connected by being the self?
Think about it eh!

Now sucks.

Now is an infinitesimal small point in time, like the point at which two perfect turning wheels make contact, so don't worry.

What about 'Time-slips' - where people have witnessed past events occurring in the present, ie. Roman legions marching across fields and then disappearing.

Time-slips: http://www.ghostclub.org.uk/winter2000.htm#Timeslips

This page is quite interesting and includes the famous Cripps-Dillons time-slip:
http://www.qsl.net/w5www/timeslips.html

I sometime entertain that the notion that 'the Present' is the product of the Past and the Future flowing together, yet we still 'progress' along 'a' Time-line. It may be that alternate Time-lines occassionally cross our own Time-line and create strange phenomena, ie. UFOs - they might be future humans in future spacecraft. Maybe, in an alternate Time-line, sightings of iced-cream vans from our line cause panic/bemusement and controversy/laughter!

I prefer the idea of metaphysical Time-travel to the nut-and-bolt, H.G. Wells variety (although, I do love what Wells does with Time-travel - its implications). I have also had the thought that 'information' could be sent from the Future to the Past. I once heard a Terence McKenna interview, in which, he said that once a Time-travel device was completed and was workable, people from the Future would appear in the lab wishing to visit the location of this landmark in human history!

As you are probably all aware, the Mayans believed that Time 'ended', periodically and that in December 21st, 2012, 'something' is purported to 'happen' - what that may be is vague, to see the least. It's really Terence McKenna's Timewave Zero computer programme that people look to as 'proof' that this date will see an 'Event' of cosmological proportions for Mankind. I am very sceptical myself, but it is a fascinating idea and McKenna talked passionately and at length about this, until his premature death from cancer in 2000.

What I find fascinating about people's perceptions of Time, is that most seem happy to accept that Infinity stretches forward in Time, but not back in Time! Cyclical Time is a strange concept to the average Westerner, but to me, it seems the most natural concept of how Time 'works'.

Even if you could time travel, if you were to return to the point of origination; it would no longer be the same point. A completely different dimension would occur whether traveling to the past or the future. So once you leave, there is no going back.

Yes there is a way back. It's called travelling back to the physical location in which you started at the same speed.

For time travel to work as we can conceive it, we must view time as linear.

If I'm moving away from you (you being defined as stationary) at a speed close to that of light, not only will you percieve me as not progressing in time (IE a clock next to you would be ticking faster than the clock next to me), but also you would percieve a massive shrink in my apparent size. But here's the kicker, if I was moving towards you, I would appear to be moving extreemly fast, and to be massively large.

Ever heard of the "twin-paradox?" Well, it only works if I move away from you and then you start moving at non-relativistic speeds towards me.

The twin-paradox doesn't work if I travel away from you, and then travel back to you at relativistic speeds.

As for this dimension BS, I want to see your logic. Not just a claim.

Here's where it get's complicated. What exactly is stationary? If I'm "moving" away from you, who's to say that mine isn't the inertial frame of reference and you're really moving away from me?

The problem is that everybody associates the inertial frame of reference with themselves. We simply can't do it that way.

The point is that until we are able to observe something (with mass) moving at relativistic speeds, we can't be sure about relativity in practice. It makes sense mathmatically, but not conceptually (in all it's facets that is).

Time Dialation is a very, very, very sticky subject.

- SOup