Where is the center of the universe?

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The discussion centers on the concept of a "center" of the universe in relation to the Big Bang and cosmic inflation. Participants argue that there is no definitive center, as the universe expands uniformly in all directions, similar to the surface of an expanding balloon. The cosmic microwave background radiation appears consistent in all directions, supporting the idea that every point in the universe could be considered a center. Some contributors express confusion about how we can observe the beginning of time from different directions without a specific origin point. Ultimately, the consensus leans toward the understanding that the universe does not have a singular center, challenging traditional notions of expansion and origin.
  • #91
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!
 
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  • #92
bytecash said:
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.)
 
  • #93
mr. vodka said:
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.
 
  • #94
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
 
  • #95
mr. vodka said:
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.
 
  • #96
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.
 
  • #97
What part of seeing the universe as it appeared in the past is escaping notice here?
 
  • #98
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.
 
  • #99
Chronos said:
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?
 
  • #100
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 realized 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.
 
  • #101
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?
 
  • #102
xrx1113 said:
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 can't 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.
 
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  • #103
We can only measure radial velocity wrt earth, direction is much harder.
 
  • #104
Chronos said:
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.
 
  • #105
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.
 
  • #106
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.
 
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  • #107
ynot1 said:
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.
 
  • #108
DaveC426913 said:
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 occurred at t=0, but it did happen.
 
  • #109
salvestrom said:
Isn't the middle bold statement only half incorrect? It may not have occurred at t=0, but it did happen.

What? That antimatter came to an end at t=0? No.

You mean why there is such a paucity of it in the universe today? Fair enough.
 
  • #110
DaveC426913 said:
What? That antimatter came to an end at t=0? No.

You mean why there is such a paucity of it in the universe today? Fair enough.

My statement was pretty clear that it didnt happen at t=0. Yes, I was referring to the fact it is supposed to have happened at some point after, leading to it being largely absent from today's universe.
 
  • #112
salvestrom said:
My statement was pretty clear that it didnt happen at t=0. Yes, I was referring to the fact it is supposed to have happened at some point after, leading to it being largely absent from today's universe.
ynot1's comments were clearly about moving backward in time toward the Big Bang. Which is completely wrong.
 
  • #113
salvestrom said:
My statement was pretty clear that it didnt happen at t=0. Yes, I was referring to the fact it is supposed to have happened at some point after, leading to it being largely absent from today's universe.
Largely absent? If antimatter ended t=0 we are now seeing it before it ended. Antimatter is now backing away from gravitational fields as it is traveling in backwards time. That means as matter separates antimatter backs off even faster because of its antigravitational effects. So it seems if it's out there it's way out there. And the more of it that moves away it could be the faster the universe appears to expand. A possibility for the accelerating expansion. I realize it is difficult to think backwards in time.
 
  • #114
DaveC426913 said:
ynot1's comments were clearly about moving backward in time toward the Big Bang. Which is completely wrong.

Which I understand. But you highlighted "the catastrophic end of antimatter" and finished by stating all the above comments are incorrect. I was only looking to point out that the matter-antimatter annihilation had occured, only not when proposed by the poster. Someone else reading this might have been unaware of this.
 
  • #115
ynot1 said:
Largely absent? If antimatter ended t=0 we are now seeing it before it ended. Antimatter is now backing away from gravitational fields as it is traveling in backwards time. That means as matter separates antimatter backs off even faster because of its antigravitational effects. So it seems if it's out there it's way out there. And the more of it that moves away it could be the faster the universe appears to expand. A possibility for the accelerating expansion. I realize it is difficult to think backwards in time.

Well I have to admit that I don't follow, but as matter and antimatter annihilate - wouldn't then this theory imply, that somewhere between big bang and end of time there will be "great annihilation"?
 
  • #116
ynot1 said:
Largely absent? If antimatter ended t=0 we are now seeing it before it ended. Antimatter is now backing away from gravitational fields as it is traveling in backwards time. That means as matter separates antimatter backs off even faster because of its antigravitational effects. So it seems if it's out there it's way out there. And the more of it that moves away it could be the faster the universe appears to expand. A possibility for the accelerating expansion. I realize it is difficult to think backwards in time.

Anti-matter was largely wiped out after t=0. I have never heard anyone suggestthat antiparticles are time-reversed before.

Has anyone else viewed ynot's link? I can't tell what's actual physics, what's being hijacked and what's getting made up.

Edit: in fact, the quote he gives along with the link is presented as if Feynman proposed it. I find that unlikely.
 
  • #117
salvestrom said:
Anti-matter was largely wiped out after t=0. I have never heard anyone suggestthat antiparticles are time-reversed before.

Has anyone else viewed ynot's link? I can't tell what's actual physics, what's being hijacked and what's getting made up.

Edit: in fact, the quote he gives along with the link is presented as if Feynman proposed it. I find that unlikely.
Actually it might have been someone else as discussed at http://en.wikipedia.org/wiki/Retrocausality:
"Feynman, and earlier Stueckelberg, proposed an interpretation of the positron as an electron moving backward in time,[15]"
 
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  • #118
ynot1 said:
"An electron traveling backwards in time is what we call a positron."

Sorry, that's not the case. This was proposed by Feynman in 1948, and falsified by Christiansen, Cronin, Fitch and Turlay in 1964. For some reason, this idea Will Not Die, despite having been known to be wrong for almost half a century.
 
  • #119
Vanadium 50 said:
Sorry, that's not the case. This was proposed by Feynman in 1948, and falsified by Christiansen, Cronin, Fitch and Turlay in 1964. For some reason, this idea Will Not Die, despite having been known to be wrong for almost half a century.

Interesting. We haven't discussed this topic in any of my university classes yet, but I have heard this (apparently false) statement in the popular science regions many times over. I was just wondering, is the idea of their disproving easy to understand? Or where can I read up on this?
 
  • #120
mr. vodka said:
Interesting. We haven't discussed this topic in any of my university classes yet, but I have heard this (apparently false) statement in the popular science regions many times over. I was just wondering, is the idea of their disproving easy to understand? Or where can I read up on this?

Hmm. Reading thru the wikipedia page on antimatter the most straightforward disproof of them traveling backward in time is that scientist create billions of them these days and we can see them. I'm pretty sure you're not supposed to be able to see something moving backward in time (a trait attached to tachyons).
 

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