star dust Posted February 23, 2005 Share Posted February 23, 2005 hello. i'm new to this site and i have a very passionate interest in cosmology. however there is one thing that i cannot get my head around. The universe is defined as all time, space and matter. everything. If the universe is expanding, then what is it expanding in to, because technically it would be the universe anyway... Link to comment Share on other sites More sharing options...
Ophiolite Posted February 23, 2005 Share Posted February 23, 2005 There have been one or two threads on this already star dust. http://www.scienceforums.net/forums/showthread.php?t=7990&highlight=universe+size http://www.scienceforums.net/forums/showthread.php?t=5188&highlight=universe+size http://www.scienceforums.net/forums/showthread.php?t=496&highlight=universe+size The usual way of explaining it is with an analogy. Imagine the Universe was two dimensional, and that it was like the surface of a balloon. If we blow the baloon up every point on the surface moves away from every other point - expansion. But it is not expanding into anything as such. Now try thinking of the Universe we have in a similar way. Just as the surface of the balloon has no edge in two dimensions our Universe has no edge in three dimensions. Any help? If not, don't worry. If you can get your head around it you are either crazy or a mathematician. [i think the two are different.] Link to comment Share on other sites More sharing options...
Cadmus Posted February 23, 2005 Share Posted February 23, 2005 The universe is defined as all time, space and matter. everything. When you say everything, you should remember that everything means only time and space, which is now in the form of space-time. If the universe is expanding, then what is it expanding in to, because technically it would be the universe anyway Not so. Space-time is expanding to where no space-time had existed. Link to comment Share on other sites More sharing options...
ydoaPs Posted February 23, 2005 Share Posted February 23, 2005 using the word where somewhat implys that spacetime is expanding into spacetime Link to comment Share on other sites More sharing options...
Cadmus Posted February 23, 2005 Share Posted February 23, 2005 using the word where somewhat implys that spacetime is expanding into spacetime I disagree. However, if you would prefer a different word, why don't you propose one. Link to comment Share on other sites More sharing options...
Ophiolite Posted February 23, 2005 Share Posted February 23, 2005 ................ where-when pronounced bar-where-when Link to comment Share on other sites More sharing options...
ydoaPs Posted February 23, 2005 Share Posted February 23, 2005 I disagree. However, if you would prefer a different word, why don't you propose one. well, "where" means distance which means space which means it is in the universe which means the universe is expanding into itself. ................ where-when pronounced bar-where-when huh? care to elaborate? Link to comment Share on other sites More sharing options...
Ophiolite Posted February 23, 2005 Share Posted February 23, 2005 Cadmus said "Space-time is expanding to where no space-time had existed" Since it is space-time that is expanding he might better have said "Space-time is expanding to where and when no space-time had existed". We contract this to where-when. But then you raise the objection that this implies there is somewhere (and somewhen) to expand into. Solution: apply a recognised 'negative' denoter - a bar over the composite word. Hence, bar-when-where. Link to comment Share on other sites More sharing options...
Cadmus Posted February 23, 2005 Share Posted February 23, 2005 well, "where" means distance which means space which means it is in the universe which means the universe is expanding into itself. I don't know about this. Once space-time expands there, it becomes a where. I do like the idea of adding when. Link to comment Share on other sites More sharing options...
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