Center of the Universe

I’m currently listening to Stephen Hawkings “a brief history”, and the following question came to me:

What is at the center of our universe? Is it incredibly dense? Why is there a center of the universe that the other universes rotate around?

There isn’t one.

I’m still not following though, doesn’t our universe revolve around something? I could have sworn I heard something to that effect-Your link Ice Wolf is helpful, and it makes me think that our universe does not revolve around anything (and that no universe does). I suppose I heard wrong though.

Thanks for the link.

I’m way out on a limb on this one, WAG-territory to th’ max.

As I understand it, the universe (according to Big Bang theory) is expanding outward from the initial burst. That energy creates the spin of galaxies, etc, but does not in itself mean the same pattern is at the centre of the first explosion outward. Which, in reality, doesn’t exist, because the expansion creates the illusion of each galaxy being at the centre, and all others racing away (mainly).

As I say, that’s just as I understand. Astronomers, please don’t hit me, I’m only an interested amateur. :slight_smile:

Meatros - are you sure you’re not getting mixed up between Galaxies, clusters, superclusters and universes?

We don’t know if there are any other universes than our own, we also can’t determine if our universe is rotating because that would entail stepping outside of our universe to observe it which to all intents and purposes is impossible - there is no ‘outside’, not that we are able to observe or interact with.

It’s highly possible. In fact I think I am.

That does make sense. As far as other universes, is there any research into that? The way I’m thinking of it is this: There is a piece of paper (all the potential space that the universe can use), and there is a dot (the big bang begining). When the dot explodes, the universe expands to 1/2 the page (the dot wasn’t in the middle of the page); is there any research that looks at the possibility of another dot on the other half of the paper? I realize that because we aren’t “outside” that we can’t observe it and really know, but I was wondering has there been any work in that area at all?

I’m probably thinking of galaxies then. Ice Wolf to be clear, as far as galaxies go; they only appear to be circling because of spin?

Circling galaxies? Are you talking with relation to Earth or on their own basis? For the former, that’s to do with our own rotation, and the observation of the movement of the stars in relation to us. The latter: galaxies rotate due to the forces of their own creation, just as with the orbits of the planets in our solar system around the sun.

It’s getting late, folks, so my apologies if that answer is off. I’m working on memory alone, here, sorry.

The big bang (from our perspective), would be more like a piece of paper that starts the size of a dot and stretches up to A4 size. As far as ‘outside’ is concerned, there may be some sort of ‘meta-space’ in which our universe is embedded, but almost by definition it is beyond the scope of our observation, futhermore things like time and spatial distance don’t exist there (or don’t mean the same thing, at least), so it would be a highly confusing place, not one to which we can really apply any reasoning based on what conditions are like inside the universe.

Maybe you’re confused with “island universes” an older term for galaxies. They tend to cluster and whenever you get objects clustering they orbit each other.

The universe doesn’t have a centre really. Think of standing on a sphere and find the centre of the surface.

Basically everything has a certain amount of angular momentum, so thing spin. As galaxies interact through gravity they

That’s about as disjointed and I can be on a Monday. Sorry. :slight_smile:

Viewing the Big Bang as a balloon or typical explosion here on earth can be useful in some instances but it is a faulty analogy.

There is no center to the universe or just as reasonably every point is the center (so yes, in a manner of speaking you really are the center of everything!).

Picture the surface of a sphere…where is the center on the surface? Same with the Universe except we have more dimensions to deal with such that our ‘surface’ is 3-D whereas the sphere’s surface is 2-D.

I don’t know if it is possible to find a center to our Universe if you could see into higher dimensions. I would think so but that’s just a WAG on my part.

I could be thinking of this. I think I have effectively explained why I am not a Astronomer…:smiley:

The Centre of the Universe

…about 3.58 x 10[sup]-12[/sup] lightyears from here.

At the center of the Universe, there is Cecil.

The standard explanation of the expanding universe is that “space itself” is expanding, and there is no center (like the balloon analogy). The expansion appears uniform from any location. I’ve always had problems with this idea - you can’t say something is expanding unless it’s in relation to something else. If you say “space itself”, ie the whole universion, is expanding, it must be relative to some external dimension, otherwise it’s meaningless. But the expansion is actually measured as the motion of galaxies within space, which doesn’t really measure the expansion of space itself (if that means anything). It seems to me that the explanations of this stuff from cosmologists are trying to come up with something that agrees with the math of General Relativity (which it has to do), but they don’t really capture some deeper explanation of reality.

Morpheus, the expansion of space itself, not in relation to anything in particular, need not be meaningless. There are many physical constants that contain units of length. If the length terms in those constants were to shrink at a uniform rate, the measurable effects would be the same as if the universe were expanding. In addition, the expansion of space has testable consequences. One finds, for instance, that the wavelength of photons should increase over time because they are stretched by the universal expansion. For this reason light emitted from distant galaxies appears redder. If instead the light were redshifted because distant galaxies were simply moving away from us through static space, the dependence of redshift on distance would have a different functional form for high redshifts.

Isn’t Earth at the centre of the universe? Seriously.

Isn’t the edge of the universe equal distance from earth in all directions, the speed of light times the age of the universe. Nothing ‘exists’ beyond this point because no information can reach us from there.

Of course, then every other observer in the universe is also at the centre of their universe.

Imagine yourself to be a two-dimesional creature living within the universe that it the surface of the ballon; being two-dimentional, you are unable to interact with the third dimension (in which the rubber sheet is warped to form a sphere); when the ballon is inflated, your universe gets bigger (in the sense that everything gets further apart), but you still aren’t able to directly see why, because that would entail taking a three-dimensional view, which isn’t possible inside your two-dimensional universe.

All depends upon what you call “universe”. Observationalists say the universe is all that you can see. Seriously, then, antechinus has a point, but it’s kind of a mundane one. We aren’t at a special place in the universe, we just can’t see beyond the particle horizon (where we meet the past).

All kinds of work is done embedding our 4-d universe into higher dimensions. The most famous of these is so-called de Sitter Space which asks you to slice along different hyperplanes to create different models of the universe. (Apologies for the technical nature of the paper and the pdf format, but there are a few pictures in the paper that will give you the feeling for what it “looks” like.)

As to the question you intended to ask, “is there a FIDUCIAL center to the universe?” the answer is, as far as we can tell, “no”. There just doesn’t have to be and since we tend to ally ourselves with Copernicus in thinking that there is no such thing as a special place there can be no center. However, this is not an open and shut case, to say the least. While we can say that we have limits on observation and dynamical causality for the universe, we can’t say for certain whether there is a “center” or not.

One thing is for sure if inflation is correct (and tomorrow, when MAP is announced, we’ll be able to say better what inflation must look like), any “size” of the all that’s in existence has blown up to such a great extent that it would be too surprising if the center was in our backyard. We just aren’t special enough, yo.

I could be wrong about this but as far as I know the curvature of our Universe does not depend on it being embedded in a higher dimensional space. Space, or any geometry, can be curved in and of itself.

The bowling ball in a rubber sheet model is a good one, as far as it goes, but there is no other “additional” dimension to make sense of the gravity of the situation, if you’ll forgive the pun.

…IOW Forget “thinking outside the box”, we’d need to think outside the whole damn universe. Pretty tall order.

This is cool. I never thought of myself as owning a universe before. “Our own universe”…now that’s what I call thinking BIG