What's up, y'all? I find it vexing to consider the boundary of the universe...and a bit contradictory. It's my understanding that to speak of "what's beyond the universe" presumes an R3 continuum, and an expanding sphere that actually has a "beyond the sphere" consideration. Is that the case with the universe? Does it make sense to talk about what's beyond the edge of the universe? If we looked far enough, would we actually see the earth? (In other words, are perimeter points identified with points on the opposite end of the universe? Most believe the universe to be expanding into something, yet modern physics declares this notion to be not true. What is your understanding of what happens beyond the boundary of the universe, if such a notion even exists?
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Boundary I have some thoughts regarding this but I'm a little jellous of them so I dont really want to post it in public yet. Anyhow, What is it about the boundary of the universe that bothers you. Are you refering to a specific publication that talked about such things and left you disturbed?
no boundary proposal you may wanna look at the No Boundary Proposal (NPB) that hawking continues to work on. I think the way he sees it: on a cosmological scale, time is equivalent to distance and vice versa. Also, that real time as we see it may be part of a (real time + imaginary time) coupling. The way I see it, if we were to somehow move to a region of space where there was no matter the gravitational effect of the matter we were moving away from would warp space-time so that it would eventually turn you around so that you were traveling back toward the same area again. So gravity plays a very important role in the shape of the universe and whether or not it would be even possible to talk about the universe having a "boundary"
quote from hawking "...the universe has not existed for ever. Rather, the universe, and time itself, had a beginning in the Big Bang, about 15 billion years ago. The beginning of real time, would have been a singularity, at which the laws of physics would have broken down. Nevertheless, the way the universe began, would have been determined by the laws of physics, if the universe satisfied the no boundary condition. This says that in the imaginary time direction, spacetime is finite in extent, but doesn't have any boundary or edge. " by Stephen Hawking Hope this helps, Jonathan
A. The universe does not have an edge. B. Even if it did, there would be no beyond, since the concept of outside of space is a logical contradiction. But that probably doesn't help, because our intuition can only imagine volumes that are embedded in greater spaces. But if you look at geometry, you'll see that you easily define a universe of any volume without needing any embedding space. Likewise, there is no "outside" beyond any 4 dimensional edge to a closed universe, otherwise it just be another part of the universe in the first place.
Re: quote from hawking This is only one way of looking at the universe, based entirely upon the subjective way that homo sapiens has experienced the passage of time during an exceedingly short sample space. It would be equally reasonable to graph time on an antilogarithmic scale. If you do that it extends to infinity in both directions and that singularity turns into something entirely different. I'd like to see a set of laws of physics that describes this model. It might be entirely more sensible and have no need for the postulation of a singularity.
I can't see how there could be a boundary. It would require a wall which would have to be dense which means it would keep going beyond that. I think the "universe" is infinite but there would be a point where there are just no more stars or rocks or anything. Just black. But then again, this area is not my specialty(obviouslyPlease Register or Log in to view the hidden image! )
Boundary of the universe The word Universe is used alot and its hard to talk about it without a Defintion. I checked around a little on the web and found this at websters online. Main Entry: uni·verse Pronunciation: 'yü-n&-"v&rs Function: noun Etymology: Latin universum, from neuter of universus entire, whole, from uni- + versus turned toward, from past participle of vertere to turn -- more at WORTH Date: 1589 1 : the whole body of things and phenomena observed or postulated : COSMOS: as a : a systematic whole held to arise by and persist through the direct intervention of divine power b : the world of human experience c (1) : the entire celestial cosmos (2) : The definition sounds vague. It seems to me people aren't exactly sure what it is. If we aren't sure exactly what it is how can we determine its boundaries. I expect most people would agree that if we were to go outside at night and point up at the sky and say, "There it is, it's the Universe" it would sort of make sense. And the universe is.....? the matter that came out of the big bang? How about that for a definition? Maybe a little more then that. Everything that came out of the big bang = the universe. I was thinking about the boundary a few weeks ago while writting something. What happens when you get to the furthest current expansion of the big bang. One thing that made me feel better was this thought. The universe is the matter that came out of the big bang. There isn't anything else. The blackness we see around the stars, well the word space is a little missleading I think. How about calling it nothing. I think its nothing. Not an endless or infinite nothing but a plain old nothing. Nothing is still nothing even if it appears to take up most of the night sky. I think its futile to look for a boundary to nothing. The universe would be the specks of matter spread out by the big bang each individual piece of which is surrounded by nothing. The size of the universe could be the furthest extent to which the great explosion has reached. " Well, whats after that ?" I ask "Nothing " I answer myself "Well there has to be something " I declare "Nope, even a whole lot of nothing is still nothing. the whole sum of that nothing out there amounts to no more then the nothing in a tiny vacume tube" I don't know if looking at it this way is original or not but it is my way and im happy with it. Yea there is more to it but this post is long enough allready and I dont wanna give anyone reason to start making fun of me.
If anyone is interested in an alternate viewpoint of the Universe's boundary, you should all check out a thread called "Another Steady State Universe Theory".
Re: quote from hawking Everytime I read something like that, I keep thinking if this will be like the whole "the world is flat" idea. He makes such a bold statement, which science will probably destroy in years to come. Thats not to say I dont find his arguments interesting or that they are not important.
hawking he certianly does make bold statements, thats why I find his theories to interesting, If it weren't for people sticking their neck out for what they think is right we would still think the world is flat.
