Right, except that “Universe” is different from “universe”, and it’s the second one we’re talking about here. Also, the question in your second paragraph is inconsistent with your first paragraph. (You might have realized these things, but I’m not sure of that from reading your post.)
Time is another dimension to our understanding of our reality in this universe. And it is helpful to explain certain concepts about our 3D world. It is not A spatial dimension. Though I agree with gr8rguy that there is a 4rth spatial dimension.
In the above example you confined you experiment to 3 diminsions. If you were a 2 dimensional being, you would have defined it in those terms, the 3rd being out of your realm of experience.
Chronos, whom I admire greatly, would disagree with you, gr8rguy. I feel he is contradictory on this issue. And quite frankly, I feel he interjects his own theory into these matters and sometimes, IMHO, they are wrong. To his credit, he admits as much.
Further, his understanding of ‘String Theory’ is weak, and I believe this is crucial to understanding a 4rth spatial dimension.
If I understand Chronos’ position from his previous posts his position is:
- The universe started with a Big Bang.
- There is no point in the universe where that happened.
- The universe has no edges.
- The universe is open.
- The universe is both finite and infinite.
- Every galaxy (discounting the ones in our local cluster) is moving away from us. This effect would appear the same regardless of which galaxy you were in.
Not to pick on him, but he rarely provides cites for his positions on these matters. Though it really wouldn’t matter, as one could provide an equally credible cite that disagreed.
There are many theories as to the shape of the universe. But I believe that if you have a Big Bang with an expanding universe, with no edges, the universe must be closed.
This brings us to Carl Sagan’s 3D model of the ballon with dots marked on it. Blow up the balloon and the dots expand away from each other. The further they are away, the faster they recede. Much like our own universe. BUT as Mr. Sagan himself points out; this is a 2 dimensional representation of our three D universe. Why didn’t he just use a 3 dimensional model?
The simple answer is -you can’t. We are trapped in 3 diminsions and unable ‘point to’ the 4rth. Just as the two dimensional dots on the balloon could not be aware of up or down - their 3rd dimension.
darkcool published:
[nitpick on] “Big Boof” !
“Bang” is too quick; too hard; too ‘bangy’. “Boof” (or, even better, “Booof”) is a much superior descriptor**:** as in, “1. The Universe started with a Big BOOF.”. [/nitpick off]
This is exactly why I rarely post here anymore.
Ahem…Sea Sorbust, first of all I didn’t name the event, second, it’s a name not a descriptor and finally, considering the laws of physics as we we understand them came into being 1/64 of a second after the initial reaction started I think, if anything, bang is not “bangy” enough!
(1) It is everything that exists.
(2) Current evidence is that the universe is topologically “flat” which means that it’s infinite.
(3) Either it’s not expanding into anything (some wild math here) or it’s expanding into something we can know nothing about (at least not yet). Some help huh?
(4) 30% of the universe’s matter is “cold dark matter” (source: Astronomy magazine, June 2001). A lot more of the stuff in the universe is “dark energy”. Good 'ole fashion matter is a small %.
(5) Yes, I suppose it’s possible given that (a) the Universe is infinite and (b) the universe is expanding at an accelerating rate and © the speed of light is finite.
any help? try this great website for many FAQs in laymans terms…
http://itss.raytheon.com/cafe/qadir/qanda.html
Sorry, darkcool. I’m afraid the post was heavily influenced by my ‘brand’ of wry humour, which most everybody finds nearly-despicable but with which I am stuck.
I believe that it was Fred Hoyle who provided the name “Big Bang” as a very deliberate insult to a theory that he found to be borderline ludicrous. (What they say about "last laughs, of course: Hoyle just recently ‘moved on’, hopefully to a place where he will find the Truth about the beginning of the Universe.)
On the other hand, my post was not meant as humor, it was just interspersed with humor to lighten an otherwise very heavy subject. All things are relative, even 1/64ths of a second. It is my impression that those who truly love and believe in this (badly-named) theory feel that the actual process was no where near as ‘punctual’ as the word “bang” would indicate—relative to the time-scale in place at the moment of the beginning.
My apologies if I offended you with the wording of my post.
Umm, actually, I DON’T believe that there is a 4th spatial dimension. Sorry if that wasn’t clear. My view is that as it’s presence or absence cannot be detect in any possible experiment, there’s no reason to postulate it’s existence.
Well, yes, that was kind of the point; I’m making an analogy to something in our realm of experience. I should, I suppose, have been more careful to point out that to a 2D being, this would be just as mindbending as a hypothetical 4th spatial dimension would be to us.
Eh, I disagree. There are, at any level we can detect, 3 accessible spatial dimensions; all the extra dimensions in string theory are compact and inaccessible at any currently detectable scale, as I understand it, not extended and inaccessible (since the latter would require some reason we couldn’t see it, while the former is just a technological limit and not a fundamental one).
This is just standard cosmology. The reason we think the universe started with the Big Bang is that it has explanatory and (as yet relatively limited in scope) predictive power.
That there is no point in the universe where the BB happened is inherent in the nature of the BB; it’s an expansion of the fabric of spacetime. (2D analogy; if you stretch a piece of saran wrap in both directions, there’s no one point that the stretching happens; the same idea holds for the BB.)
That the universe has no edges is merely a manifestation of size. That it is open is I think more debated (I think it’s now thought to be flat, but the evidence is not conclusive), but open or flat, it is finite in age, but infinite in lifetime (i.e. there will be no Big Crunch; this merely follows from some math).
Lastly, that galaxies are all moving away from us (at large scales) is established observationally; this observation is predicted by the Big Bang, although the rate is not.
gr8rguy my apologies. I was ‘speed-reading’ (ha ha) and mistook your quote of ultrafilter about 4D as your post. Unforgivable.
Concerning the above 6 points, yes I realize this is standard cosmology. And I have no quibble with them. I merely stated my perception of Chronos’ belief system to make the point that, to me, they add up to a closed universe and Chronos has stated he believes the universe is open. I’m not suggesting he is wrong. I’m suggesting I think he’s wrong. There is not enough evidence to know either way.
And I disagree that no edge = manifistation of size. Care to elaborate?
Flat, curved or saddle-shaped, current thinking is always changing. I see no reason to think that right now we’ve solved this riddle.
I do not have an opinion the big crunch. I don’t feel we can properly assess the amount of matter in the known universe. Could you provide a cite for your apperent statement of fact that there will be no Big Crunch? Regardless of the math, you have to have accurate numbers to plug into the equations and I don’t believe we have them.
My point on the fourth dimension is this: you can use all the balloons or loaves of rasion bread you want, but until you can provide a working 3D model of how the universe works (excepting the universe itself, of course) (i.e. all objects moving away from each other regardless of your position) you have to conclude we live in, at least, a 4 dimensional existance.
All I’m asking, before everybody goes scurrying off to their textbooks, is to try to picture how this model would work. Believe me, if you could, people would stop using 2D models to show how 3D works and start using 3D ones.
SS, sorry. I over-reacted. Still, despite things being relative, given the age of the universe, 1/64th of a second does seem a indescribably small %, eh?
Oh, think nothing of it. I certainly didn’t, other than wanting to clarify the record.
How do we get a closed universe out of this? The possibility isn’t entirely ruled out, but it seems fairly unlikely. I’ll get back to this in a minute, but what Chronos has apparently said (I’ll take your word for it) seems consistent to me.
I may be a little out of my depth here, being more into field theory than relativity, but if the universe is infinite, logically it has no edge. Of course, this is also true if it’s closed. (It may also be admitted that there’s probably an element of wishful thinking here; being able to ignore boundary conditions is very convenient.)
Well, especially now that we have the BOOMERanG results, we seem to find that Omega ~ 1, and there’s zero curvature. The data is not adequate to tell us how much mass there is, but it seems overwhelmingly likely that there is a substantial cosmological constant, not enough mass to, by itself, keep the universe from being open, and zero curvature. (Also, note that with Omega so close to 1 currently, we need it to be 1 within some hideous precision in primordial times, like 1 in 10[sup]60+[/sup]. There is a widespread belief that if if it were that close to 1 at one point, it would be unthinkable that it WEREN’T one; hence the statement that Omega really IS 1, despite the cited the range of possible values.) However, I should qualify my statement to be a statement of opinion; given the correctness of standard cosmology and current observations, it is not thought that a Big Crunch will happen. This does not mean it won’t.
Umm, no, it just means that we can’t visualize it because our frame of reference is intrinsically limited to 3D, and our intuition is limited to Euclidean geometry. That is, the only reason to postulate an extra dimension is that it makes our intuition happier because we’re used to 2D things in our 3D world, so we can visualize by analogy. But it makes no nevermind as far as the math and physics is concerned, and it’s basically a matter of preference; some people prefer to postulate it because it’s simpler to understand things on those terms, other people prefer not to because there’s no a priori reason to assume it. I am one of the latter, and I guess you are one of the former, but as far as the science goes, each view is equally meritorious.
A cite on the above
Consarnit, Sorbust, I thought you were calling me. I came running all the way from an orgy with Smurfette, Jean Grey, and Scooby Doo’s sister to see what the problem was! Bah!
Watch that in the future…
Since Mars is a part of the Universe, it seems that this might be an OK place to say that, at last, NASA has gotten around to planning a manned mission to, and a semi/quasi-permanent outpost on, Mars. 
For today only (Wed., Sept. 19), a wallpaper-sized, full color graphic (“artist’s conception”), in three different sizes, of NASA’s planned Martian Outpost, is available for download from the Cosmiverse.com site. 
(A different wallpaper each day. 
)
Your NASA cite, ring is very nice but it evades an interesting question (provided you believe in the “BB” Theory): “What/Where was what is today called Space before there was matter/energy/gravity?”
It seems to me that the NASA answer essentially says "There is no such thing as Space. :eek: 
As with Euclidean geometry (with metric), I suspect that we all treat time as if it is a “linear” (or “uniform”) measure rather than a more general, possibly nonlinear measure. Everything we do is based on the belief that an hour today is exactly the same as an hour will be tomorrow, and that both are exactly the same [“length”] as an hour was in 1813.
If you really do believe in the “BB” Theory, then it seems pretty clear (–to me, anyway–) that the measure-content of a second at the very Beginning, is quite a bit different than the measure-content of a second today.
(As proof I offer**:** a 
and a 
! )
[sub]Don’t, please, anyone breath too hard, lest we disrupt SPOOFE again from some essential activity. :)[/sub]
Yours truly, 'orbust