Where is the Centre of the Universe?

Eqqus - don't tell me - your from there once??? LOL

Welcome, one and all. It's good to see old faces here (the facelifts have done wonders for you).

Did I hear the big gun terminologies coming out? Barycentre and hyperspace! Yikes - this is going to get complex.

Alright, you asked for it...if we're going to define "centre" then let's throw "Zero Point Energy" into the equation. Otherwise, what is the importance of defining the centre of the Universe as being relative to a gravitational mass?

Ros and Satt, over to you...

If the force from the Casimir effect (or zero point energy) is proportional to

A/(d^4) (A: area, d: distance)

and if it is a key to the accelerating expansion of the universe, then the barycenter plays smaller role in the argument of the "center", if any, than a world where the gravity solely plays the vital role.

Hi Bib,

What about zero point energy? What about Einstein-Rosen bridges, singularities, folded dimensions, what about anything else I can think of... could you be a little more specific? Or did you just want to plop a term on the ground and let us do a jig around it

Satt,

You say, "the barycenter plays a smaller role in the argument..."

I submit that "barycenter" in relation to the universe, can not play any "smaller"' role than it currently does, because we already know that it is a meaningless term in relation to the "universe" (though not to a galaxy).

I would also suggest that any form of dark energy, whether it be Casimir or other, also does not give a foundation from which to define a center. All of these effects, whether known or not, still exist within a coneptual environment (the universe) which we do not know the boundary conditions for.

If we're going to try to bound this, then we have to consider time as much as space. And if we do that, the center becomes obvious (at least based on current physics). The Center would be The Beginning.

Ros: you forgot to mention String Theory and the Cosmological Constant.

Jig? Have you ever seen an Irishman jigging?

Bib, your last post was great! Maybe you and rosborne could put an act together!

JM

rosborne..
If the universe is finite (or bounded from above in the numerical sense), then the barycenter could be defined for a given time section of the universe, which might be "everywhere in the universe" for the time section.

Satt: that's an interesting proposition...I'll need to think about it.

Anyhow, my point is that unless we know the extent and location of a bounded Universe, if you can believe that at all, then it must have a centre.

I don't accept the Big Bang Theory as a good model for analysing this issue, instead, I believe the White Fountain Theory holds the key to the real evidence that is displayed in our Universe...

Bib..
From a math intuition (sorry, not by evidence in my case), assuming the existence of a regular region beyond a singularity seems very natural.

Satt,

Is the Universe finite?

rosborne..
The question must, perhaps, be the one not answerable properly.
I have a somewhat queer impression about the notion that the expanding (part of) universe is infinite, though the thought by itself has no contradiction. "The (relevant) universe is infinite but the scale is expanding" .. consistent, but sounds very strange. If the scale is expanding, then it might be more natural to think that finite something is being enlarged. Of course this is not a firm argument for the finite (relevant) universe.

Satt,

I agree with your comments.

Another thought:

The only boundary dimension we know of, for the Universe, is time. And it's only bounded at one end. How many other dimensions are there, of which we are not aware, and do they exhibit boundary conditions which can be applied to the Universe?

rosborne..
Some say, you know, there can be seven more dimensions (7=11-4) to be considered. The 7-dimensional subspace of the full 11-dim space is said to be compactified not to be observed currently. And, they amount to say, it was when the intensity of energy of the universe was extremely hight that the not-yet-compactified extra 7-dim subspace played significant roles.

Hi Satt,

Yes, I'm familiar with this idea from string theory. I have trouble seeing how boundary conditions could arise from any of these extra compacted dimensions.

People have called time the fourth dimension, but to me it's the first. I wonder if being the first, it's special, in that only it creates a boundary condition for the universe (and only at one end).

Regards,

I do not think the possibility of higher dimensional spaces could have any effects on the boundedness (I am taking "boundary condition" in this sense, right(?)) argument merely from the higher dimensionality itself. Extra dimensional ((10 + 1)-dimensional) space is compactified (except for 1 + usual 4 -dim subspace), and the compactified space cannot be unbounded, and hence only the remaining 4 (+1)-dim space has the possibility of being infinite.

A possible interpretation as to the usual 4-dim space is that a finite (bounded) space can be a some kind of projection (stereographic projection or other) of an infinite (unbounded) space, and vice versa. Both can be mapped one-to-one, and enlargement of the bounded space can be a projection of scale-extending unbounded space. If one thinks in this way, the distinction between boundedness and unboundedness of a space could lose its significance. The concept of "space" is in the realm of theory, any way.

Thanks for the comments Satt...I'm reading them with interest.

"[T]he Universe may not be the same in all directions."

http://news.bbc.co.uk/1/hi/sci/tech/2814947.stm

......................... excerpts .....................
"We had expected that the microwave background would be truly isotropic, with no preferred direction in space but that may not be the case."

Looking at the symmetry of the CMB - measures technically called its octopole and quadrupole components - the researchers uncovered a curious pattern.

They had expected to see no pattern at all but what they saw was anything but random.

"The octopole and quadrupole components are arranged in a straight line across the sky, along a kind of cosmic equator. That's weird.

"We don't think this is due to foreground contamination," Dr Tegmark said. "It could be telling us something about the shape of space on the largest scales. We did not expect this and we cannot yet explain it."

It may mean that the CMB is clumpier in some directions than others. Some theories of the structure of the Universe predict this but observational evidence to support it would be a major discovery.
......................... end of excerpts ..................

We do not know if the universe is finite or infinite -- although most scientists agree that the part of the universe derived from what they call the Big Bang -- is finite.


According to scientists, the center of the universe (even this part derived from the Big Bang) is everywhere in the universe.

Every place in the universe, according to them, is the center of it. (Something about the universe curving around into itself or somesuch.)

Seems to be a contradiction here...but, hey...I'm not a scientist.

According to most Big Bangers the Universe's origin was finite - surely an expanding Universe, after the alleged Big Bang, would still remain finite?

Satt, do you know where the apparent cosmic equator is supposed to be?

A few years ago someone calculated electromagnetic polarization anisotropy and determined that the axis of the universe ran in the direction of the constellation sextans. I think that the idea was quickly refuted, but if the MAP anisotropy is along the same line, it would be interesting to find out why the universe has a direction.