Oh, shit.
why do people always associate time with a path or line that can be followed. I’ve been toying with the idea that time just is. it’s not something you go through or follow along, but something the universe just lives in. I’ve got no real evidence to support this theory, just some ideas. I think of the past as something that only exists in our minds and the future doesn’t exist either because it just hasn’t happened yet. thus you can’t travel back into time because there’s nothing there and you can’t travel to the future because if you did, then it would become the present. how does this relate to the op? if the universe starts to collapse I don’t think “time” will run backwards because the past doesn’t exist except in our minds. I think we’ll keep advancing, growing, evolving, etc. like we always have. does this sound plausible to anyone else but me?
aceospades: The past doesn’t just have bearing on our minds… If there’s a broken eggshell on the ground right now, then it’s safe to say that there was an egg sometime in the past, regardless if anyone knew about it at the time. In fact, the concepts of “past” and “future” are relevant for any system complex enough to have a definable entropy. As for your argument for time travel being impossible, it’s equivalent to saying that travel to different places is impossible, because no matter where I go, where I am is “here”.
Thanks for your reply Chronos, very informative.
[hijack]Oh, and about time travel; I thought a theory had already been proven that it was possible? Something about two super-charged plates, and a wormhole. I know that this is just theory, but I do recall that an experiment was done with two plates and the very start of it was created in a lab (though this was just the very start, since the energy needed would be much greater). However, you could only travel back to the place in time when the “time-machine” was created. Anyway, this is something altogether, but I also remember some theory that time would always sort itself out, and wouldn’t let a paradox like the Grandfather Paradox take place.
Oh, on a side note, this thread(including the name) reminds me of the Isaac Asimov (sp?) book “Eternity Inc.” At least I think that was the name. [/hijack]
There are localized regions of space that are already not expanding due to gravity, and the physical laws still hold. Expansion of the universe takes place in the empty megaparsecs between galaxies.
“Timeline” - - because we move forward through time one point at a time. If it was “timepoint”, then nothing would change. If it was “timeplane” then there would be no causality (as we know it anyway).
It does seem plausible (a fact, even) that time is a one-way arrow, although no one knows why.
I went home last Friday intent on digging up my copy of Brief History of Time but then remembered I had lent my copy out and don’t have it. IIRC Hawking doesn’t believe that the cosmological arrow of time will reverse if the universe started contracting. He did the teacup thing as a prelude to his more developed ideas further into the book.
My question is why should entropy decrease if the Universe started contracting? Is this an absolute given (entropy decreasing) if the Universe contracts?
Silent_Rob
As to your hijack…
I have also heard of that method of time travel. If you search this board you’ll find PLENTY of threads on time travel. I think the Moderators (among others) are learning to hate them although I personally love that stuff.
Quick and dirty on your method of time travel is that while it theoretically might work I heard the energy required to move a person through time in this manner would require the conversion of the entire mass of Jupiter to energy. One side effect of this energy density would be the absolute destruction of the person foolhardy enough to attempt it.
Naw, the person isn’t important to the experiment… The really worrisome thing about those energy densities, is that they’d probably wipe out the wormhole that you’re trying to use. We would need negative energy density to pull it off, and the Casimir effect (the two plates) MIGHT be able to give us that, but probably not.
By the way, silent_rob, the book you’re thinking of is The End of Eternity, and it was Asimov’s attempt to prove that he could write a time-travel story. He failed. You can go through the whole book, and replace every instance of “Century” with “Planet”, “time” with “space”, and “physiotime” with “time”, and the story would be essentially unchanged. Now, if you want a real time travel story, read Heinlein’s short story “By his Own Bootstraps”… Anyone remember what book that was in?
Thanks, Phobos. I always like a concurring opinion. I’m wrong so often that it’s a rare treat for me. 
The Menace from Earth. I recall it as ‘By his Bootstraps’, but I am losing over a million neural connections per day at this point.