centre of the universe?

[rpmath]

<font color="yellow">After all these posts, i still beleive that the universe must have a centre. any 1st, 2nd, 3rd dimension objects must have a centre, and so must therefore any 4th, 5th and so on..<br /></font><br />The center of a 2 D (D=dimension) circle isn’t in its 1 D limit line.<br />The center of a 3 D sphere isn’t in its 2 D limit surface.<br />The center of a 4 D hyper-sphere isn’t in its 3 D limit hyper-surface.<br /><br />I think the universe is like the surface of a 4 D hyper-sphere (may be it has another geometry, I don’t know), and you cannot put its center somewhere on its hyper-surface, like you cannot put Earth center somewhere on its surface.<br />

 

[rogers_buck]

The universe does has a center and it lies back along the axis of imaginary time. The point where the universe was plank sized. Not a singularity, but a pole if you like, in imaginary time.

 

[anoolios]

I think there is some confusion stemming from a misperception of "high school physics". Big bang theory states that there is no <i>center of expansion</i> of the universe. An observer at any given point in the universe should see spacetime expanding in all directions.

 

[zenith]

but how can there be no centre of expansion, if all expansion was made from one point in time and space? it is a physical impossibility for there to be no centre to a deminsional object. it is possible for spacetime to be expanding in all directions from any point in the universe AND have a centre..<br /><br />the theory isnt tried and tested. the theory is only that, a theory. an idea based upon observations. the problem with many people is that they cannot conceptualize things that arent stated as "correct" or "accepted"

 

[alokmohan]

In an expandig balloon there isno center of expansion.

 

[zenith]

but there is a single point in the CENTRE of the balloon in which everything is expanding away from

 

[mtrotto7287]

true, but if you were inside the balloon, and you could not see the boundary of the balloon (or just can't tell it apart from everything else around you)- then how would you be able to find this "central" point?<br /><br />I agree, in reference to the big bang theory, there should be a centre somewhere- we just don't know HOW to find it

 

[alkalin]

but there is a single point in the CENTRE of the balloon in which everything is expanding away from <br /><br />Correct, but this may not represent the universe. BB is only one theory.<br /><br />If I had one of those fancy coordinate transformation units aerospace and auto manufacturers use, finding the center of a balloon either from the inside or outside would be a piece of cake for some instantaneous point in time. The necessary condition is to see the surface of the balloon.<br />

 

[meteo]

We are not inside the balloon we are on it's surface that is why there is no center in 3-dimensions, there may be one in 4 dimensions. However, if the center was in the 4th dimension you could never "go to" the center, the center is in the past since time is the 4th dimension.<br /><br />In our 3 dimensional universe everything gets farther away from everything else. Like all points on the surface of the balloon get farther away from other points on the balloon at the same speed. In the past the balloon things were much closer to each other (on the surface). The balloon has expanded things are now farther away (on the surface).<br /><br />The past state of the balloon is inside the present state of the balloon. The center of the balloon is the begining. At the beggining of the universe the balloon was so small as to "resemble" a point. Perhaps a better illustration is not a balloon but a 4 dimensional onion of infinite size. The core of the onion is past, the layers are states of the onion in time. However, this is how an outside observer existing in 4 dimensions sees the universe. <br /><br />When you are looking at the night sky you are looking into the "past of the universe" the surface of a cone that is a point at our layer and extends into the onion. I say a surface of a cone because we see the past along the surface we do not see the past of our position on the surface (the cone's center). So our visible universe is a cone extending from "our layer" down. All observers have their own cone and all observers see the same begining when they look out as far as they can. However, we are only related to people on our layer on the other side of the onion by a common view of the past. Our future cones will intersect in the future with the cones of observers on our layer. The many cones is analogous to the many billiard balls of the previous post.<br /><br />However, this illustration fails because the universe is expanding and an accelerating rate. <br /><br />

 

[absolutezero]

So are we in an agreement that the Universe probably has a center, but we can't determine where it is, so to us there is no center because without looking at the universe from "outside" we can't find it?

 

[mtrotto7287]

sounds good to me {:OP<br /><br />although it is quite frustrating

 

[Maddad]

One potential problem with finding a center to the universe, accepting the controversial existence of it in the first place, is that the visible universe is probably very much smaller than the entire universe. What we can see is 13.7 billion light years in radius, but the parts that we are seeing today that are 13.7 billion light years away were moving away from us at nearly the speed of light 13.7 billion years ago.<br /><br />Where are those parts today?<br /><br />If you accept that space can expand faster than the speed of light, and in doing so carry objects with it faster than the speed of light without outraging Einstein, then we can put those ancient parts as much as 150 billion light years away from us today, making the radius of the entire universe about 11 times what the radius of the visible universe is. This makes its volume 1,300 times the volume of the universe that we can see.<br /><br />One interesting consequence of this line of thought is a hole in the suport for one of the pillars of the no-center-to-the-universe theory. One reason that we say there is no center is because we look around us and see all parts of the univers receeding from us proportional to the distance. We do not see a portion of the universe in one direction receeding faster than a different portion in a different direction. However, with the entire universe being much larger than what we can see, we are shielded from being able make such an observation. It is still possible to have this isotropic recession within the small bubble of our visible universe and have differiential recessional speed in the overall universe.

 

[absolutezero]

Just curious, are we assuming space is in fact spherical? is this a theory and if it is, why not a square shape? Ok, rephrased, what is the shape of the universe?

 

[kmarinas86]

By peering into our inner universe, we can make a good guess as to the stucture of the larger universe. The Universe most likely resembles an eliptical or an spiral galaxy, just as how a disk galaxy resembles the disk surrounding that of a proto-star and how galaxies passing through each other resemble insoluble particle liquids floating, colliding, and mixing in a sea of empty space.

 

[meteo]

Also, mass in the visible universe is uniform so it would make sense that it is not different outside our visible universe, at least realitvly nearby to the visible universe. In other words when we look out into the visible universe it doens't look special. So we are probably seeing a small part of the whole. Of course it's only speculations when you are talking about what cannot be seen.<br /><br />I would argue that "the universe receeding from us proportional to the distance" is evidence for the no center theory. Sure, not being able to see much is a downfall. But I can't belive there is a center (in our 3-dimensional view, a universe that is not uniform interms of matter) until we find it is not uniform. We won't have this new evidence for billions of years when we can see farther, so the no-center theory has some evidence for it, the center theory doesn't and won't for billions of years (barring theoretical conclusions).<br /><br />I think a more interesting related question would be is the universe open or closed. If it is closed then it will one day come back to a point (sort of a center). If it is open the universe will expand forever,

 

[meteo]

No

 

[zenith]

The shape of the universe doesnt matter, because it is going to have a centre, no matter what.<br /><br />a dot has a centre.<br /><br />a line has a centre.<br /><br />a circle/square/parallelogram has a centre.<br /><br />a sphere/obloid/paraboloid/cube has a centre.<br /><br />therefore a 4th dimensional sphere(which is what i am told the universe is by one) or the saddle shape or whatever, must have a centre.<br /><br />and hence the universe, or our universe, or our multiverse or whatevr you want to call it must have a centre. The location of the centre will more than likely be never found, but the fact that it exists is the point.<br /><br />i have realised all this after the many views that have been posted, and there have been many conflictions of theorys.

 

[alokmohan]

BB is merely one theory.It may be wrong also.If you cant explain so many things it is wrong.

 

[nexium]

Hi metro: You are correct I think, except a billion years from now we will see less, not more of an expanding Universe. The gaxaies we see 13 billion light years away (at present) will be receeding at faster than light speed and thus not detectable unless we have new technology or a new theory, both of which are likely. We will see more volume, but fewer galaxies as they will be wider spaced by then. The evidence of a center will be even farther past the edge of the visable universe. Neil

 

[nexium]

Those one, two, and three dimentonal things you mentioned do have centers. I'm unsure about a 4th dimention as we are at one point in time. Many more dimentions have been hypothesed, often without center being an element of the hypothesis. You likely should not say "must have" Neil

 

[zenith]

granted, and i take back my "must have", and replace it with a "if following the trends, would be likely to have"

 

[alkalin]

"BB is merely one theory.It may be wrong also.If you cant explain so many things it is wrong."<br /><br />Agreed. I find the universe far easier to explain logically on the basis of a SS theory, but with the caveat that it did have a beginning. The universe is just a whole lot older than 15 billion years. There is also a bunch of evidence from physics that also supports SS.<br /><br />I could go on, but I think this is getting off topic.<br />

 

[qzzq]

Thanks for that link eburacum45. Interesting stuff. <div class="Discussion_UserSignature"> <p> </p><p>***</p> </div>

 

[Maddad]

AbsoluteZero<br />"<font color="yellow">Just curious, are we assuming space is in fact spherical? is this a theory and if it is, why not a square shape? Ok, rephrased, what is the shape of the universe?</font><br />When I was talking above I was thinking of infinite, flat, unbounded space. That is the simplist; whether it represents reality is debatable.<br /><br />meteo<br />"<font color="yellow">I would argue that "the universe receeding from us proportional to the distance" is evidence for the no center theory. Sure, not being able to see much is a downfall. But I can't belive there is a center (in our 3-dimensional view, a universe that is not uniform interms of matter) until we find it is not uniform. We won't have this new evidence for billions of years when we can see farther, so the no-center theory has some evidence for it, the center theory doesn't and won't for billions of years (barring theoretical conclusions).</font><br />That's an interesting thought, but even in billions of years it won't give you your answer. Say we let another 10 billion years slide by. At that point our visible universe is 23.7 billion years in diameter, but still only shows us the same bubble of the overall universe that our previous view did. It will just be enlarged, but we will not be able to see any more than we could see before.<br /><br />Actually, we would be able to see less than before. Those objects that are now at the outer limits of visibility are receeding from us almost at the speed of light. As the universe gets larger, those objects would be further away, so they would be receeding from us faster than the speed of light. They would forever be beyond our ability to observe. As more time passes, more and more of what we see now will disappear from the visible universe.<br /><br />nexium<br />I see you advanced the very same argument.

 

[jatslo]

That just goes to show that you cannot believe everything that you read ;o)<br /><br />---Jatslo