Thanks for the lesson, but it's actually not what I meant, my fault I suppose... I acutally understand Relativity theory quite well.
Sorry Kosh, easy to misinterpret what is actually being said on forums.
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I disagree that beyond the universe is a philosophical question...
My assumption that the universe is "somewhere" is no more right or wrong than your assumption that the universe is "infinite". You just finished talking about the Hubble constant and not being able to see behind it, so how do you know that the universe is infinite? So you don't belive in the "Big Bang"?
Actually, I didn't say assume or say that. What I said was that if the universe is infinite, then the "whats it expanding into" question is moot, and if it's not, then the fact that we're bound to it means we'll never be able to see outside it anyway, which is why I reckon it's a philosphical issue. The Hubble "stuff" is simply what is currently accepted theory explaining the expansion of the universe and I was merely attempting to explain it.
BTW, can you point me to any valid research/literature on the matter/energy density issue and its affect on expansion?
I must admit I find modern cosmology absolutley fasinating. The fact that most of the universe is made up of a substance/ energy we no nothing about makes my imagination soar.
It's incredibility fascinating isnt it, and frustrating at the same time. There are so many theories and so many unanswered questions.
Getting back to what I think was the main question in this tread, re. the density of the universe, it's another one of those (as yet) unanswered questions. From what I've read it's not so much a mass problem as even dark matter will still leave us 60% or so short, but a vacuum energy density question, re dark energy.
Still hairy fairy when we still don't really know whether the universe is open, closed or flat.
So the universe is not actually about 15billion years old, only the matter contained within it?
I dunno really, it would depend on what you define as the 'universe'. Does the universe include all of the 'nothing' into which it is expanding? How can 'nothing' be said to have an age? I guess I'm saying yes - I can only see the matter within the universe as we know it having an age of approx. 15 billion yrs.
The void that the universe is expanding into would have had to pre-exist the universe, otherwise how could the universe expand into it?
And gravity - what the heck is it anyhoo? You can see it's effect on everything, but where does this force actually come from? Can anyone show me a gravitron particle please....
Basically it makes my head hurt hehe... I think I'll just look at the heavens and go 'wow' instead
Still hairy fairy when we still don't really know whether the universe is open, closed or flat.
a doughnut shaped universe. Mainly because it's a nice shape & I like the taste of doughnuts.
I realize that this is probably not very scientific, however I'm entitled to my theory however ill-informed or ludicrous it might be. And anyhoo, if by some chance it does turn out to be doughnut shaped then I will be famous & rich for having thought of it first...
This is why I thought that you asre siding with the infinite:<!--StartFragment -->
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Originally Posted by AGarvin
If the universe is infinite, which I think current theory suggests, then there is no boundary.
If I misunderstood I apologise. You of course have a right to your own opinion, and I'm not rying to force mine onto you. I still disagree with the idea that this is a philosophical question though.
Simply knowing your Genetic makeup doesn't mean I know or understand the person. Knowing your place within things does help. Science is learning to understand the atomic structure of the universe and some of the laws governing it, but this does not help us understand it. When we first knew that those faint fuzzies in our scopes were other Galaxies, we looked at them from an external perspective and learned much about our own Milky way. Science is happy to research into how the universe was formed, but that too could be seen as being "Philosophical", yet we belive the answer is invaluable in understanding the universe. Anyway, enough about that.
I don't have time too look up anything more "valid". Friedmann, you might know him. Look under "The beginning of everything". I'm not sure if this answers you question.
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And gravity - what the heck is it anyhoo? You can see it's effect on everything, but where does this force actually come from? Can anyone show me a gravitron particle please
All in all, being less expert in these topics, I found the article to be a good reference. While the numbers for relative sizes and distances are helpful, I wonder if it's possible to include links in the article to pages like this that picture the planets side by side. http://www.rense.com/general72/size.htm
I thought these were wonderful images. If they are anywhere near being accurate, they would impart a visually stunning sense of relative size. Better yet, of course, would be to include these images in the article, but I'm not sure of the legal copyright issues that may be involved. In any case, I'm hoping that someone more expert than I am will look at these pics and comment on their accuracy. Thanks!
Thanks for that Blue fire and thanks for pulling this threat out .
I was listening to something re infinity on the BBC and the point was made that effectively you can not have a percentage of infinity. So if our Universe is indeed infinite there can be no point at which it started . Not withstanding inflation you can not start with a finite object and double it up until it becomes infinite. There is no point where the boundary between finite and infite can cross. So if we start with a big bang we can never (on that approach) end up with a Universe that is infinite. In that context to have a start there must be a finite dimention to the Universe. But then what does this finite "object" exist in? nothing? Well the nothing must be infinite otherwise it can not be nothing and it can only be nothing for this is what our Universe must expand into .
My point was the BBC show said that it was common for people working on the infinity concept to go crazy and I conclude they are indeed correct.
alex
G'day all,
I was taught somewhere along the path to utter confusion that infinity was simply undefinable, or something like that anyway.
I think the idea was connected with integrals being between +/- infinity as opposed to definite integrals. (side issue.....Calculus is not like riding a bicycle..... if you don't use it ; you loose it)
To my simplistic mind, if I can say that the 'known universe' is 'x' parsecs from side to side, and I conceed that there is bound to be stuff beyond my present reach, then I am justified in saying that the universe is in fact of undefinable size; i.e. infinite.
The question of what the universe might or might not be expanding into is somewhat moot because the undefinable edge of the universe might or might not exist; it is beyond my reach. If this is so, then the answer to the question is beyond our reach and must forever remain so.
What I draw from the approach is if there was a big bang irrespective of the rate of inflation the Universe can never become infinite therfore althought the edge is beyong us there must indeed be an edge (an end to it as it is not infinite it can only be finite having started at some point). Indeed we can never get past a point (Cosmic background radiation form apprx 300,000 years after the start I think it goes) but I cant help but wonder if the Universe has an "outside". And I dont take any of this too seriously but enjoy the silly speculation you see me involve myself in.
alex.
A definition of infinite used was...you can take a very large section away from the infinite and you are still left with infinite ..I guess we could try that with the Universe and conclude infinite but still I would think that you could not say there was a time where the Universe was a percentage of its current (infinite) size and quote a number. Is it cloudy your way bet you can guess the conditions here
alex
Perhaps the 'big bang' was just a local incident. Could matter exist as matter under the preasure and temperature, not to mention accelerations of a humungous bang powerful enough to propel shrapnel zillions of parsecs in all directions?
The local, and for convenience sake, most recent 'big bang' might just have been energetic enough to reverse the drift of other more remote and senior 'big bang' products that would otherwise have been more or less converging on us.
It could be sort of like watching a pond of water during a light 'April shower'; as the shock wave from one drop meets the wave from an earlier drop, the trend is to overwhelm the lesser wave. But some does get through the newer wave front you say? Yes true, and just how is it that we see galaxies colliding now and then? Could it not be that the odd galaxy gets through the shock wave as it were, and keeps on with its original trajectory, ultimately colliding with what ever gets it the way?
Can there be an outside of an infinite thing? Seems not in a 3 dimentional mind set, but if there were other dimensions not bound to the 3 dimensions it could be feasable. Consider the 'Mobius Ring'; (below picture 'lifted' from http://www.ka-gold-jewelry.com/p-pro...ing-silver.php)
it has diameter, width, thickness, but in a sense, unmeasurable circumference. What volume of space does it enclose, or how much gas/fluid can be contained within it? What really are its boundaries?
Yet it does have an outside, a region beyond itself........or does it?
Actually the mobius ring has a calculable circumference a tad more that 2 PI x D, but the thing is, you can walk and walk along it till the cows come home and be no nearer the end than when you started.
But the surface of a mobius strip is not infinite. It is indeed finite, But it is not bounded. The surface of a sphere (like earth) is finite but unbounded - there is no edge. Continuing in one direction on the surface of a mobius strip or the surface of a sphere will ultimately bring you back to where you started, yet you met no edge.
If the Big Bang was the start of our universe, then that was where time and space and matter/energy was created. There is no sense in asking what came before the big bang since there was no time until spacetime exapanded into existence. I believe our universe could be finite but unbounded (no edge) in the same manner as the surface of a sphere. Except that our universe (and the 4 dimensions we are aware of - spacetime, 3 spatial and 1 time dimension) may be the surface of a hypersphere for example. In my view, our universe does not have to be expanding Into Anything. Mainstream theory posits that space itself is expanding. Like the surface of a balloon being blown up. The surface of a balloon does not expand "Into" anything - the surface material (space) is simply stretching/expanding. Now we are not talking about the 3D sphere of the balloon expanding into surrounding 3D space, we are simply talking about the "surface" expanding. So, If our "surface", our universe, is expanding it does not need extra dimensions to expand into. A flat, 2D piece of rubber can be stretched or expanded without needing a 3rd dimension. And it can also be stretched/expanded if that flat piece of rubber becomes curved back on itself to form the surface of a sphere. We are not talking about forming a sphere - we are talking about changing the geometry of the rubber to form the "Surface" of what we, in our 3D world, would call a sphere.
Whew! Hope I haven't lost myself. That's just my 2 cents and admittedly most probably flawed idea of things.
Very interesting Doug I like it.
Blue fire I can not dismiss the question of what could it be that we may be expanding into and feel that the ballon parrallel even suggests that there must be a region into even the ballon must by its expansion occupy..as it does...as a ballon inflates all that is said of the conditions on its surface are correct observations however as it inflates it does occupy more of the space arround it... Even if the Universe can be parralleled to a ballon I would think it will still exhibit the same conditions on "its surface" however the edge is moving into something. Dont get me wrong I dont have a clue but I enjoy the speculation past the big bang
alex
was the main question in this tread, re. the density of the universe, it's another one of those (as yet) unanswered questions. From what I've read it's not so much a mass problem as even dark matter will still leave us 60% or so short, but a vacuum energy density question, re dark energy.
If they are anywhere near being accurate, they would impart a visually stunning sense of relative size. Better yet, of course, would be to include these images in the article, but I'm not sure of the legal copyright issues that may be involved. In any case, I'm hoping that someone more expert than I am will look at these pics and comment on their accuracy. Thanks!
. Not withstanding inflation you can not start with a finite object and double it up until it becomes infinite. There is no point where the boundary between finite and infite can cross. So if we start with a big bang we can never (on that approach) end up with a Universe that is infinite. In that context to have a start there must be a finite dimention to the Universe. But then what does this finite "object" exist in? nothing? Well the nothing must be infinite otherwise it can not be nothing and it can only be nothing for this is what our Universe must expand into
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