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Where is the center of the universe?

by JediSouth
Tags: universe
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Greylorn
#91
Jan7-12, 09:32 PM
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IMO you are correct. Your analysis is one of others which expose the absurdity of Big Bang theory.

I can afford to agree with you because my theory of the beginnings, which would never be allowed here, does not incorporate a singularity (which would represent absurd physics, no different from claiming that God did it) and has a different explanation for both the observed expansion of the universe as well as its acceleration.

None of this will help you any unless I publish, but at least you know that you are not alone. Keep thinking!
nonequilibrium
#92
Jan7-12, 09:48 PM
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Quote Quote by bytecash View Post
This still does not make sense, there HAS to be a "center" of the Universe under the big bang theory, even if it is a ball or balloon blowing up, there is still a CENTER or middle of the ball or balloon. Even if there are no "edges" of the universe there is still a geometrical point of center. If the universe started from one point in space and expanded in all directions there is a center even if it is a moving central point.
I think you're simply misunderstanding the balloon analogy. The balloon actually tells the story for a two-dimensional universe. In that case the "center of the balloon" isn't a part of space at all! If people were to live in a 2D world, the balloon analogy would be exact (but then again, people in a 2D world can't imagine an inflating balloon, so they would use the analogy of a closed loop getting bigger).

Anyway, for our 3D spatial universe you have to inflate a "balloon" in 4D instead of 3D. You see that the "center of the balloon" isn't a part of our physical reality at all.

(To be exact, you'd probably need a 5D space, as time is an extra dimension, but that's besides the point in this discussion.)
DaveC426913
#93
Jan7-12, 10:20 PM
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Quote Quote by mr. vodka View Post
Anyway, for our 3D spatial universe you have to inflate a "balloon" in 4D instead of 3D. You see that the "center of the balloon" isn't a part of our physical reality at all.

(To be exact, you'd probably need a 5D space, as time is an extra dimension, but that's besides the point in this discussion.)
In fact, not only do you not need a 5th dimension, you do not even need a 4th. The mathematics of a curved 3D space work out just fine without needing to invoke a 4th dimension in the equations.
nonequilibrium
#94
Jan7-12, 10:22 PM
P: 1,412
Hello Dave. Can it be that you misread my post? Otherwise I don't understand your objection. I was saying that the correct balloon analogy should be a 3 dimensional balloon in a 4 dimensional space (the 3D balloon then playing the role of our 3D space), but of course such an analogy would be useless due to not being able to imagine it :p
DaveC426913
#95
Jan7-12, 10:32 PM
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Quote Quote by mr. vodka View Post
Hello Dave. Can it be that you misread my post? Otherwise I don't understand your objection.
No, and I wasn't objecting.

Pointing out that the 2D balloon analogy is like our 3D universe expanding into a 4th dimension is tantamount to suggesting that our universe would have a center - in that 4th dimension. That is going to send bytecash the wrong message.

The balloon analogy is simply an analogy because it shows someone how it is possible to have an object that is finite yet has no centre. But you don't want to carry the analogy too far, or you defeat the lesson. We don't want bytecash thinking our universe has a center in some 4th dimension.
Imax
#96
Jan8-12, 01:10 AM
P: 186
Expansion from a center is not compatible with the notion of a homogeneous and isotropic Universe. If the Universe did expand from a center, then the observed expansion rate would depend on how far you are from the center.
Chronos
#97
Jan8-12, 04:31 AM
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What part of seeing the universe as it appeared in the past is escaping notice here?
nonequilibrium
#98
Jan8-12, 08:14 AM
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The balloon analogy is simply an analogy because it shows someone how it is possible to have an object that is finite yet has no centre. But you don't want to carry the analogy too far, or you defeat the lesson. We don't want bytecash thinking our universe has a center in some 4th dimension.
True, I should have noted that, but bytecash's post seemed to suggest, at least to me, that he thought that our universe was actually expanding like the balloon does, i.e. as a 2D sphere expanding in 3D space, and that is why I wanted to point out that the balloon analogy was merely a substitute for something we can't imagine.
petm1
#99
Jan15-12, 06:08 PM
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Quote Quote by Chronos View Post
Do you agree every observer in the universe perceives they are as far away as possible from the 'center' of the 'big bang', 'now'? [given the finite speed of light]?
I agree with this. Do you think that every observer also perceives they are as close as possible to the 'center' of the 'big bang', 'now', given the finite speed of mass?
salvestrom
#100
Jan16-12, 01:26 AM
P: 226
I was immensely please with myself when I finally got to grips with this question a few days ago. I think I deserved to be, having been struggling with it for two decades. =D

What I realised was that since the universal singularity consisted of all space and all matter/energy then that energy occupied all of space. So when it went up like an intergalactic roman candle, all energy was evenly distributed and blown apart. Essentially, the entire universe, at every point 'exploded'. While the universe, or more specifically, space may yet turn out to have a center, an edge, or neither, the location of the Big Bang itself was everywhere.
xrx1113
#101
Feb3-12, 07:19 AM
P: 1
OK i'm new to this site but i was wondering why: if we can see the red shift/blue shift of galixies and we know they are moving can't we tell by the degree of red shift/blue shift which direction they are going . If galixies are going in a strait line they are leaving where they were, if you drew lines backwards from them at some point they would all intersect at the center of the universe, dosn't that tell us where to point the telescope .
Am i totally wrong?
Cosmo Novice
#102
Feb3-12, 07:43 AM
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Quote Quote by xrx1113 View Post
OK i'm new to this site but i was wondering why: if we can see the red shift/blue shift of galixies and we know they are moving can't we tell by the degree of red shift/blue shift which direction they are going . If galixies are going in a strait line they are leaving where they were, if you drew lines backwards from them at some point they would all intersect at the center of the universe, dosn't that tell us where to point the telescope .
Am i totally wrong?
Yes.

If we trace all motion for everything we can see - the center is our galaxy - all galaxies are moving away from our galaxy. If we were in Andromeda then we would see Andromeda as the center.

This can only ever tell us the Observable Universes center - the point is this; most mass in the Universe has not moved a great deal since the Big Bang (barring individual kinematic motion which is almost negligible on large scales) , the BB was not an explosion in the traditional sense but can be explained by expansion of the scale factor.

Scale expansion does not require a center. You can attribute a center to the Observable Universe but as we know the Universe is much much larger than the Observable (even if still finite) then this has no relevance to the U as a whole.

If the Universe is infinite then it cant possibly have a center and if it infinite it is bounded in a way that any point can be the center.

The only centers are for observables and the only edges are for temporals, there can be no centers or edges to the Universe as a whole - it would contradict the Cosmological Principle.
Chronos
#103
Feb3-12, 08:33 AM
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We can only measure radial velocity wrt earth, direction is much harder.
petm1
#104
Feb3-12, 10:09 AM
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Quote Quote by Chronos View Post
What part of seeing the universe as it appeared in the past is escaping notice here?
I like to link the past through the center connection of mass, like a compass needle that always points north, mass always points back to its common beginning inward.
mjacobsca
#105
Feb3-12, 10:48 AM
P: 98
Is it possible that space expands in wirey filaments, or like branches of a tree, such that our observable universe is only one small branch on an enormous tree with no center? Do theories of inflation all assume a perfectly uniform inflation of space? I always wondered if it were possible, based on quantum effects, for *inflation to spread out like a tree, in a non-uniform way on large scales, and our small viewpoint only capable of seeing our tiny branch.
ynot1
#106
Feb4-12, 01:01 PM
P: 90
If you follow Einstein's logic you have to consider the universe as 4 dimensional and treat all dimensions on an equal footing. So if you ask for the center of the universe you have to ask what is the center of time. This only makes sense from Feynman's perspective if you say matter moves in forward time and antimatter in reverse time. So it seems the center of time is at t=0, the big bang, where apparently spacetime originated. This would also represent the catastrophic end of antimatter, at least from its perspective, when it all converged on a single point. Since that time antimatter has been retreating back to its past, at least from our perspective. Strange.
DaveC426913
#107
Feb4-12, 02:23 PM
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Quote Quote by ynot1 View Post
This only makes sense from Feynman's perspective if you say matter moves in forward time and antimatter in reverse time. So it seems the center of time is at t=0, the big bang, where apparently spacetime originated. This would also represent the catastrophic end of antimatter, at least from its perspective, when it all converged on a single point. Since that time antimatter has been retreating back to its past, at least from our perspective. Strange.
Antimatter does not move backward in time. The above statements are all incorrect.
salvestrom
#108
Feb4-12, 02:57 PM
P: 226
Quote Quote by DaveC426913 View Post
Antimatter does not move backward in time. The above statements are all incorrect.
Isn't the middle bold statement only half incorrect? It may not have occured at t=0, but it did happen.


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