Sayonara Posted March 30, 2005 Posted March 30, 2005 Then does it not follow that under such conditions, conservation laws will only restrict the manner in which time travel is employed, and not prevent it completely?
Johnny5 Posted March 30, 2005 Posted March 30, 2005 Then does it not follow that under such conditions, conservation laws will only restrict the manner in which time travel is employed, and not prevent it completely? What do you mean?
Sayonara Posted March 30, 2005 Posted March 30, 2005 Conservation of energy doesn't give two hoots if my time machine is over there by the window, or parked outside on the drive. If "where" my time machine is located does not matter in terms of conservation, why should "when"? As long as the object being displaced exists for the same total period that it would have done without displacement, I don't see a requirement for a contiguous presence in spacetime.
Johnny5 Posted March 30, 2005 Posted March 30, 2005 As long as the object being displaced exists for the same total period that it would have done without displacement' date=' I don't see a requirement for a contiguous presence in spacetime.[/quote'] You seem to know something about this. Have you thought about this problem before?
Sayonara Posted March 30, 2005 Posted March 30, 2005 Yes, briefly. It's not something you see coming up very often though. If there is a requirement that works against it, I've not heard of it. But I'd certainly be interested.
eeemmm Posted April 30, 2005 Posted April 30, 2005 every direction you go you will find that space ends that way space has a shape
who_knows Posted May 1, 2005 Posted May 1, 2005 every direction you go you will find that space ends that way space has a shape like four walls of a box or house you mean?but there is space beyond that Space is needed for everything to exist,so one would have to ask the question.What is beyond space and the first thing that existed.Nothing?
BlackHole Posted May 1, 2005 Posted May 1, 2005 Physical space is abstract and depends on the absolute. If one removes the absolute, then there is no physical space. Gottfried Leibniz (Sir Isaac's nemesis) rejected the physical existence of space, absolute or otherwise. I believe he was correct. Only the absolute is physical (matter and energy), the relative is abstract (only in our head).
bascule Posted May 1, 2005 Posted May 1, 2005 Space is flat, therefore it has to end! That logic worked great in the past Although it's looking more and more like space actually is flat, but obviously we can't prove that definitively yet
[Tycho?] Posted May 1, 2005 Posted May 1, 2005 I hate these time travel arguments. To simply say that time travel is impossible because paradoxs are impossible is a rather childish way of looking at things. There are way to many things we dont know, like causality, how time travel would actually work, how time actually works. To simply say that paradoxs are impossible when we dont even know if time travel is possible doesn't make sense. Until we get a much much greater understanding of how these things actually work, you can't say time travel is possible or impossible, its all just a blind shot in the dark.
nomadd22 Posted May 12, 2005 Posted May 12, 2005 If you walk around the Earth, do you find the end? But the Earth's surface isn't infinite. You just have to expand your thinking one more dimension to apply that concept to the universe.
Severian Posted May 12, 2005 Posted May 12, 2005 If you walk around the Earth, do you find the end? But the Earth's surface isn't infinite. You just have to expand your thinking one more dimension to apply that concept to the universe. That is not a good analogy, because the data implies that you will not come back to the same place if you travel in a straight line across the universe for long enough. Actually, whether or not the universe is infinite is another unscientific question (this site seems to like these) since it is untestable. the best you can ever do it say that it is bigger than the the size probed so far. This isn't just pedantry; since there was probably a period of inflation at some point, our past light-cone is not the whole universe, so there are part of the universe with which we can never come back into causal contact with. Ergo, we can never see the whole universe to know how big it is (even if it were finite).
higezzzz Posted May 12, 2005 Posted May 12, 2005 I cant think of a way that it would or wouldnt end. i guess it would have to end somewere.
Ewen Posted May 13, 2005 Posted May 13, 2005 As long as there is a universe, more could be made? I'm unsure because new matter isn't being created like it was shortly after the big bang.
BlackHole Posted May 13, 2005 Posted May 13, 2005 I'm not even sure the universe had a beginning. The origin of the CMBR is not completely understood. It could be that there was no beginning and no end.
Ewen Posted May 14, 2005 Posted May 14, 2005 I think the Big Bang theory is fairly well supported. Objects are red-shifting. In reverse, they'd be blue-shifting and ultimately would (theoretically) for a singularity? The big question is what came before that? But, obviously, we don't know.
Guest reader Posted May 25, 2005 Posted May 25, 2005 I believe that the universe is 4D. For instance if you could bring a 2D person to Earth their 2D brains would not understand the concept of 3D objects and would not see the 3D universe in the first place. This is like us 3D humans, we are unable to understand the concept that the universe has a 'Fourth' dimension. dark matter could also be 4D as it cannot be see or detected by anything 3D but we know that it has a fundamental part in the creation of the universe
ed84c Posted May 25, 2005 Posted May 25, 2005 erm, it IS 4D. You mean 4 Spacial Dimentions, however if that were true then the 4D stuff would be able to leave this universe. Let me explain that, thing of 2D drawing, how can you leave that univers (paper), well stand, up, gaining a verticle dimention, hence becoming 3D, similiarly the same applies for 1D "line universes" btw what is the plural of universe?
Mag Posted May 26, 2005 Posted May 26, 2005 I dont know if this has been said before, so if it has, sorry. but one theory is that it does end, and where it ends, it begins on the other side. (similar to that video game, where if you go off screen, you return on the opposite side, going in the same direction) so yeah, that way, it can end, but if you go too far, you will end up on the other side, which would make it infinite, in a confined space.
aj47 Posted October 29, 2005 Posted October 29, 2005 I have always understood the universe as having boundrys where space time is bent into a higher dimension. For example it would be like 2 dimsional beings on a piece of paper that had been bent into a sphere tring to escape off the edge. Any one else heard that theory, i think it was mitchio kaku who said it. Also someone pointed out that if the universe was infintite and had been there for ever, when we looked at the sky it would constantly be lit up from the infinate amount of light from the infinate amount of stars. Sorry hope this hasn't been said already.
EvoN1020v Posted October 29, 2005 Posted October 29, 2005 Let me succinct what the space is all about. Space is like a big image of mathematical properties. Therefore the distance of voidiness is infinity as in [math]\infty[/math]!!
BenSon Posted October 30, 2005 Posted October 30, 2005 I must apologise if someone has already said this but I only got up to page four. Ok how about this for a model of the universe, it is a sphere with an expanding radius. We all exist on the surface of the sphere sort of like spacetime only curved not flat. `Scott
kenshin Posted December 6, 2005 Posted December 6, 2005 Our universe(space-time) is like a balloon.We live on its surface.So even though it is finite,it never ends.One can go around and around forever and it never ends.
kenshin Posted December 6, 2005 Posted December 6, 2005 Well!I am sorry.i just read the last post,its same.So my reply makes no sense.
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