Does the UNIVERSE have a boundary or OUTER LIMIT?

Well, as I pointed out, currently all the theories assume homogeneity as an initial assumption, meaning they outright assume there is no limit to the universe..so the thought experiment is still not valid under any model of the universe today! Note, however, that it would be a valid thought experiment under the expanding volume theory that I just proposed.

rosborne, go ahead and laugh...but at least I had the balls to post a proof on the subject, which you have not made ANY attempt to find flaw in, and yet you guffaw...now that is funny.

g__day, #1: I didn't say it was CMB that was revealing structure where none should exist...quite the opposite, I noted that CMB does not show structure, and pointed out that I did not take this as reliable evidence for their being no structure everywhere. I don't know much about this fractal stuff but I have heard you make comment on it before. It is funny though, because apparently this ALSO calls into question the homogeneity assumption that so many people (like rosborne) take on faith.

#2: technically, we don't really know what is and is not possible. but according to the relativistic framework (which we cannot verify), it actually is (hypothetically) possible to pass information faster than light speed in 2 ways that we know of so far: one of them being quantum teleportation via entanglement, and the other being manipulating spacetime to create intentional ripples in the fabric of spacetime, which is not limited by special relativity.

Homogenity is a big call to make, and I'm not sure why it was there other than simply to make any relativity based model work. Without that supposition I understand the mathematics would have been way too hairy.

Personally I find fractals an intriguing take, that is yet to be seriously wide-spread studied. If it were true it would be both elegant and extremely powerful in what it could predict and how it might link cosmology and relativity - right down to to a quantum mechanics framework. However it would introduce almost the ultimate in infinities - so all scientists would want to know why are we inserting this into our models unless there is both a strong theoretically underpinning and alot of physical evidence for it.

On the quantum entanglement breaking local relativity - let me think that through. If it doesn't violate Heinsenberg (which I can't see it would) it may be a strong candidate. I need more brain cycles on that one.

I don't need to find a flaw, I have the luxury of simply repeating what mainstream physics already defines. Your 'proof' is in conflict with the basic model. So rather than assume that the Big Bang model is incorrect, I will just take the easy way out and assume that your proof is not valid.

Don't get me wrong, I like your enthusiasm, but logic works better with brains than balls. Good luck.

Actually sending information via quantum entanglement faster than the speed of light is a bit of a hairy subject...as I recall, basically if you have two entangled particles A and B, then you force A into a state, it automatically forces B into a known state no matter how far away it is. But you can't read the state of B directly without changing it. So you can send the information faster than light, but to read the information you'd need to conventionally send information about the state of A to the receivers at B.

There is a lot of obviously bogus information about fractal universes on the web...do you have a link that talks about some actual well founded research? I must admit that I am highly speculative, it would take a good deal of evidence (more than I would expect them to be able to gather) to convince me of that!

TRUTH requires both brains and balls. Balls are required to challenge certain outdated notions that are still believed for no good reason, and brains are required to judge what "no good reason" is.

French research that ponders is the Universe Fractal (scale invariant at all sizes). One theoretican has gone so far as to postulate spacetime itself may be fractal, and labelled the physics with this set of underpinning scale relativity. A fractal universe, by definition, is infinite.

The most interesting part of the article (based on the work of Laurent Nottale at Meudon Observatory in Paris) was looking at the size of fractal structures found in the Sloan study, a super cluster streching 200 million light years was found to have a fractal pattern. Now galaxies and clusters have fractal matter / energy distributions. But with our current understanding of cosmology and relativity under big bang scenarios there should be no fractal structures beyond 30 million light in diameter for a Universe only 14 billion years old. So it points to more research and study needed to say why we find this anomolay.

This research (further study of SLOAN) is due to be complete by mid 2008, be interesting to see what they find. Meanwhile several physicists are tryung to understand why the universe in this model would be fractal, and whether particles following a fractal geometry of spacetime might explain and link us to the world of quantum mechnics.


A bit more here:

http://www.chez.com/etlefevre/rechell/ukrechel.htm

http://www.geocities.com/amselvam/soliton/solit.html

and

http://space.newscientist.com/article/mg19325941.600-is-the-universe-a-fractal.html

Those links are mostly out of date and lacking in any actual data, but they did lead me to a leading researcher in the area:



Here is a publicly accessible and easily readable publication on the subject by Dr. Pietronero:

http://arxiv.org/PS_cache/astro-ph/pdf/9611/9611197v2.pdf

Some key points from the article...



I like this quote because it is the same argument that I keep saying...and people keep ignoring because they just WANT to believe that they can fit a model to the data, ignoring the fact that the assumptions necessary to do so are unfounded (absurd).



Yes good point, and that is just explainable by regular gravity.



So the visible universe is fractal, however

1) We already expect things to appear fractal at least locally just due to gravity in combination with some vague initial cosmic imprinting, but where is the proof that the crossover scale (to homogeneity) should be less than the visible range? lacking?

2) Now that I think about it....actually, fractal nature at all cosmic scales seems like it should be expected. Either the big bang started with complete homogeneity, or it was a little bit inhomogeneous. But we know there was some inhomogeneity because we have clustering of atoms into stars and galaxies...with TRUE homogeneity, in an expanding universe model, it would be impossible for anything but perfectly evenly spaced atoms to occupy the universe.

Given some inhomogeneity, in an expanding universe model, we must (as pointed out) expect fractal nature at small cosmic scales because of gravitational interactions that cause clustering...and there is no reason I can see that this would break down at any [cosmic] scale. I see no relationship to atomic/subatomic scales though.

limits of universe?
I think what we see and feel through our senses is not the actual reality..in other words the universe around us is what out senses make us to believe....and hence the 'vast expense' of universe is nothing but an effect of our senses which may not be there at all.

Is the Universe something that surrounds me or does it include me? If the former is the case, I'm extra-cosmological and have no abode. If it's the latter--if I'm inherently part of the universe--then it cannot (at least not from my "logic") have a limit. Let me explain by the cartoonish analogy I gave earlier. If I could travel at such a hypothecial speed that I would eventually arrive at the end of the universe, I could not "leave it" because, as part of it, I would merely be expanding it.

But, then, I have no confidence in the ability of human logic--good or bad--to address such problems; that's because our logic creates them in the first place.

Of equal importance ... if the answer be yes does that impose an inner boundary?

the answer evading you
Alright guys, here's the answer, and it's crystal clear. I have read through all the pages in one sitting and stayed interested even through the water-boundary & jello diatribe. I've suffered through some badly speelld words as well.

I could pretend to be the brains of this operation and spout some stuff about the quantum realm, of 0 or 1 at times being 01 or 10, and try to tie that into the codons of protein synthesis or binary discussions between pc's. I could talk about the dual simplicity & complexity of water, of mechanical waves, of wave as particle, particle as wave, and the x & y of sex chromosomes. Yes all of that speaks to me in universal talky-talk, here and now, prepare ye for one of those 'Covey paradigm shifts' ...here's your answer:

The thread is the universe or an accurate model thereof. No, not string theory, but the collection of posts on this topic contained within these pages. It is actively being created, it has a beginning, it has direction, it has a past, and it even contains matter (albeit a relatively small collection of electrons). Does it have an end? This post is it once I submit. More importantly, the period at the end of "The End." (which I just hypothesized to exist) will be the leading edge of the universe we create, created, and are creating. That is until the next 'person without my final & correct answer' replies It is hard to imagine what will stretch beyond my post but the space is there for it to exist, it just has not been created yet. Is there a red light at the end? That's a new question, probably for Able2Know.com's webmaster to answer. In our universe that question has to be posed to an entirely different and vastly more knowledgeable webmaster. (whoever/whatever you believe that to be)

The End.

Amen

yes brick wall i built it

Day Ettie.

YEs, Universe Has A Limit
Everything Has A limit And In Physics No object is there THat Has No limits...
So universe Also has a Limit.
Like A Sphere Has No Dimensions And is Infinite But Can u Say It Does Not Have Limits....??? Sphere Also Have Limits, So has Universe.

Universe Is Made In A shape That Has A longitudinal ANd Latitudinal Paths WHich Are in Circular Shape ANd Are Combined Together To Form A Bunch Of Rings, The same thing is Universe.

And Einstein theorized that if a person or object traveled long enough in a straight line (ignoring the affects of gravity and obstacles in your way) you will eventually reach your own starting point and begin to retrace your own steps. How can this be so? Well, as the theory goes, Space-Time is actually curved in such a way that the time line that we follow is similar to a Mobious Strip <sic> (what you get when you take a strip of paper and give it a half twist then reconnect the ends, thus forming an object with 'apparently' one side and no ends).

So if i Reach The End of The Universe I Think i May Find Wall Of Glass Reflecting Us. If you've played Arcade games like Snake of Asteroid, then you know what I am talking about. You exit one way, you reappear the other side. Or the limit acts like a mirror, and you think you continue for ever, when you actually just "bounce" off the mirror. SO THE THING IS THAT UNIVERSE HAS A BOUNDARY AND DOES HAVE LIMITS.

which universe? ... assuming of course that 'infinity' is a valid concept

yes


or depending


no

it all depends

All my intuition and thinking leads me to posit that the Universe's geometry or topology will be its most startling trait. I honestly think we will find at very, very small or very,very large scales reality is not 3 dimensional.

So given its topology is at present unknown - its hard to talk about edges or limits. Distance may not be what we think it is, whilst geometry is not deeply understood I think its is too premature to ask this question is such an absolute (and inherently 3d) way.

I firmly sit on the fence here saying we simply don't have the framework of physics to come close to remotely answering this one - I ponder if in my lifetime whether we will or not?

I think under this simple question hides the greatest unknown in modern theoretical physics today. Let's say dimensional reality and all relativity is fractal (a distinct possibility) - how would one answer your question then if there is no finite edge because their is no finite anything?

Most likely this has already been said, but if you've ever played asteroids, it's like that, but 3d, and there is no edge of the screen, just a repetition.

I think this century alot more though will be given to what is time, what is space and how do matter, energy and space really interact. Until we have the tools to explore this much deeper, we won't make real progress on questions usch as this.

Yes, our universe have boundry but it is not visible. I am sure that there are crores of universe like ours. But we have limitation to know about those. Even we dont know all about our universe.

Ghanshyam Patel