Article: The Structure and Proportions of the Universe

[iceman]

Hi all.

The Cosmic Sentinel has kindly written a great article The Structure and Proportions of the Universe.

You can read the article at the IceInSpace Articles (http://www.iceinspace.com.au/?projects) page, or directly by clicking on the link below:

The Structure and Proportions of the Universe (http://www.iceinspace.com.au/index.php?id=63,266,0,0,1,0)

Thanks to The Cosmic Sentinel for his contribution.

If you'd like to submit an article/how-to/review for the site, please contact me.

[iceman]

Placeholder replaced with article. Bumping.

[kosh]

Howdy Iceman,
Interesting play on ratios.
Apart from a few numbers being debatably incorrect good article, 'cept for
one thing. Footnote 6. While I think I understand what "The cosmic sentinel" is getting at, this 'considered' theory suggests that the speed of light (1x) and the speed of expasion of the universe (say 1.2x for arguments sake) are cumulative? ie. 2.2x light speed? I don't believe so. The speed of light would simply be expansion (1.2x) minus light (1x) = .2x! Expansion wins. If the universe was collapsing, then the light would reach us, but still at the same speed. If we were talking about special theory, with light always going away from you at the same speed no matter your speed, then this is an effect of "Time Dilation", something light is not affected by, purely perception.

[AGarvin]

Yep, one or two figures incorrect, but it illustrates the point, and it does say

Footnote 6 also incorrectly suggests that the redshift caused due to the expansion of space is a doppler effect, which is quite wrong. Doppler is a described under Special Relativity, cosmological expansion under General Relativity.

I'm also confused about the authors interpretation of how light from superluminal objects still reaches us :confuse3:. It's either doesnt not understood or greatly oversimplified.

Cheers,
Andy.

[AGarvin]

Ooops, please ignore the one or two grammatic errors in my last post. the kids were jumping all over me and I hit submit before a proof read. DOH!

[kosh]

Also very true, good point AGarvin.

I hope it doesn't sound like we're "bashing" your efforts to supply some
useful information iceman, i for one am not.

But some points needed to be corrected as it is wrong to speculate with no solid grounds on which to correct the entire scientific community on their
horrible lack understanding on what is really a basic concept. :prey2:

The other reason is that I personally love cosmology and welcome any chance
to dicuss it. :nerd:

[AGarvin]

Definately not trying to "bash" so I hope I havent offended anyone. There are some aspects of cosmological expansion that are quite counter-intuitive. I've even seen it wrong in books. Bit of a worry really.

[stinky]

The concept of recession at greater than light speed raises several problems. Including fringe mass being greater than the remainder of the universe - this implies unrestrained net energy growth - if we start fom a singularity this is not possible.

However the approaching light speed recession model doeas give explanation to unexplained dark mass.

The question is - do we expalin unaccounted dark mass with eisting theory or agree we've missed something entirely - yet to be discovered? !

[AGarvin]

I'm curious, why do you say that superluminal recession implies a "fringe mass" greater than the rest of the universe and a corresponding net energy growth?

[stinky]

Superluminal objects implies an increas in mass.

[AGarvin]

Your confusing Special Relativity with General Relativity. The whole mass-energy thing (aka e = mc2), and indeed the speed of light restriction is described under Special Relativity, which governs the motion of objects through space. Comsological expansion (aka the expansion of space) is derived from the Freidman-Robertson-Walker metric using General Relativity and there is no such restriction. This is probably the most misunderstood aspect of the whole big bang/expanding universe model. Think of it as one laying down the rules within the bubble, the other laying down the rules of the bubble.

Within any local frame of reference, the speed of light will always be constant (Special Relativity), even though to a distant observer an object might be receeding superluminally (General Relativity). But even the distant observer will still only see the light reaching them at the speed of light, just cosmologically (not Doppler) redshifted.

This stuff can really do your head in :scared: .

[stinky]

Looks to me that the outer edge of the"bubble" is then lost too us thanks to - Special Relativity?

[AGarvin]

Kinda. Here's how I'm understanding it.

The distance at which you pass from sub to superluminal recession is known as the Hubble distance. The Hubble distance is derived from the Hubble constant, but the Hubble constant however actually changes with time (not sure why yet, still digesting that one), so the Hubble distance is actually increasing. As a result, the light from these objects can eventually be "caught" by the increasing Hubble distance and cross from super to subluminal recession and begin it's forward journey towards us. I think the Hubble distance is believed to be at a redshift of about 1.5, but we have observed objects out to redshift of over 6.

You also have the case of objects that were within our Hubble sphere when they emitted the light we're now seeing, even though they are now receeding superluminal.

Having waffled on though, there is a point at which we cannot see beyond, called the particle horizon which defines our observable universe.

That got my head spinning :P . Hope it makes sense.

[kosh]

all good points, very interesting chaps.

If I can go back a point, i think the idea is that E=mc2 constraining the speed of the expansion is fine for our space-time as we know it, but, with the universe expanding, I would assume that it would be expanding into SOMETHING. That "something" we don't understand in the least and probably not meant to (yet). So we don't really know what rules govern the speeds in that place for lack of a better term. On the other hand, there must be a tremendous amount of energy involved in order to make the universe expand, in the right conditions, this may be allowing left-over energy to cross to matter, accelerating expansion, or at least allowing for the basic builing blocks to fill the void, a self sustaining cosmos yes/no?

Maybe a bit far fetched but i'm willing to entertain it for arguments sake. :confuse3:

[stinky]

I don't see the need for an expansion into SOMTHING - just what IS expanding. The amount of energy / mass in the universe is THE question - there appears to be too much mass - so the search is for this dark matter as yet undetected, which may even be greater than the sum of all known objects.

[rochler]

even comprehending the simple things in Astrophysics - like 'Hubble's Constant'. If it is a constant, then why does it vary? Why shouldn't it be called Hubble's Variable instead? Or perhaps 'Hubble's Mostly Constant'. No wonder it's all very confusing...

[AGarvin]

Fair point. This is why it is often and more correctly referred to as the Hubble parameter, I think the term "constant" is more of an historical term. Hubble basically discovered that the universe was expanding, and determined a rate of expansion. The theories that determined its "variability" came later.



The speed of light restriction is a Special Relativistic "law" governing the movement of matter through space. It has nothing to do with the expansion if space itself, which is basically the geometry of space as described by General Relativity.

As far as what the universe is expanding into, it's really a philosophical question. If the universe is infinite, which I think current theory suggests, then there is no boundary. If it is finite, then the fact that we are confined to and can never see beyond the boundary means we will never know. It's an unanswerable question.

[rochler]

dunno why anyone would get hung up on what the universe is expanding 'into'. I've always assumed it's expanding into nothing in particular. Seems to me that most of the universe is comprised of vast quantities of nothing, with occasional bits of something....

However, without wanting to aggravate any learned Astrophysicists out there, I'm very sceptical about many of the theories that have been evolving in this field for many years. Their very complexity smacks of people desperately trying to find 'answers' within the very confusing and contradictory observations that have been made over the years. I really can't comprehend string theories & multiple dimensions, dark energy/matter etc.

I find that E = Mc2 is much more elegant. I prefer to entertain the belief that eventually someone brilliant will stumble across an equally simple/complex & yet elegant unifying theory/formula to explain how it all works.

For example, if you look at the mathematical formula that generates a Mandelbrot Set, you will see that it appears relatively simple. But look at the absolutely incredible images it can generate, which it appears to do to an infinite level.

I think we are at the same sort of stage that Watson & Crick were before they finally hit on the correct structure for DNA. Did you ever see their first model of what they thought it looked like? You would laugh now, since we all know how symmetrical & elegant DNA actually looks, but then these pioneers persisted & finally figured it out. Maybe Astrophysics will be a similar situation.

But then, what the heck do I know about it? Nothing.... I'm the guy who thought that a 'quark' was the sound you get when you step on a duck....

[kosh]

Thanks, i didn't know that the reason for the expansion is because there it a "little" too much matter. :prey2:

In fact, expansion of the universe slowed for a time, probably once the original momentum from the big bang dissipated, and gravity took hold, then accelerated again, this must mean that matter is being produced / converted somehow and that is why this is happening. Dark matter fills a large portion of our universe (so the theory goes) i'm aware of that too.



Thanks for the lesson, but it's actually not what I meant, my fault I suppose... I acutally understand Relativity theory quite well.

My point was in support of one of your earlier statements in a way,


Is this not Special relativity? The speed of matter rule WITHIN the bubble?

Also (while i'm going on about it),
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"? After this expolosion (which originated somewhere), the universe got bigger, then bigger, and bigger still until... It suddenly had no boundry and became infinte? Maybe I should continue to eat more junk food until I get so big that I become infinite too. :scared:

If there is no boundry, then what we are really taking about is the "Distribution of matter within an infinite universe", not expansion, which is what everyone is referring to. If there was too much matter in the universe to begin with then it would have continued to expand exponentially and would not have stopped to form stars and planets, Therefore it cannot be "infinite". In fact, it WAS pretty much perfect, that is why we are here discussing it. Something is changing, that is the issue, and if the "boundries" of the universe are not expanding then the cosmos is becoming denser. Is there any evidence that it is becoming denser? I don't think so. So, the universe is getting bigger.

So let's remove the previously mentioned SOMETHING that we apparently have no need for, and watch as the universe becomes denser, and finally collapses in on itself under the force of gravity all the while, counting the amount of atoms contained within it. Not that we''' be here to see it! :lol:

[kosh]

So the universe is not actually about 15billion years old, only the matter contained within it?

[AGarvin]

Sorry Kosh, easy to misinterpret what is actually being said on forums.



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?

[mickoking]

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.

[AGarvin]

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 :confuse2: 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.

[rochler]

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 ;)

[rochler]

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... :P

[AGarvin]

Cheezes and doughnuts ... your going to end up cholesterol lowering drugs like me .... :lol:

[kosh]

This is why I thought that you asre siding with the infinite:<!--StartFragment -->




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.

Try this link: http://www.pbs.org/wgbh/nova/einstein/relativity/

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.



Good question....

[Blue Fire]

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. :thumbsup: 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!

[xelasnave]

Thanks for that Blue fire and thanks for pulling this threat out:thumbsup: .
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:eyepop: . 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:shrug: :P :D .
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.:lol: :lol: :lol: :P ;)
alex

[Doug]

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.

Confused?.....................me too!:confuse3:

[xelasnave]

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.

[xelasnave]

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:D 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:lol: :lol: :lol: bet you can guess the conditions here;)
alex

[Doug]

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? :screwy: :shrug:


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-products/mobius-ring-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?:whistle:

[Doug]

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.

[Blue Fire]

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. :)

[xelasnave]

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