There must be a center of the universe....?

In summary, the assumptions made in this conversation result in the following conclusions:1. There may be a theoretical center to the sphere that contains the entire universe.2. If the universe is finite, it does not need to have a center.3. The universe can annex more of whatever it has been annexing.
  • #36
curious Tom said:
Numerous illustrations regarding time cones show the elsewhere to be the space into which the universe is expanding.
Artists are not physicists. The people who come up with these illustrations do not have a good understanding of physics. They draw whatever they want in the name of ' artistic license'. Illustrations and artist's concepts are not good things upon which to base your understanding of physics.
 
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  • #37
UncertaintyAjay said:
Artists are not physicists. The people who come up with these illustrations do not have a good understanding of physics. They draw whatever they want in the name of ' artistic license'. Illustrations and artist's concepts are not good things upon which to base your understanding of physics.
Yeah ! What he said.
 
  • #38
I will try
phinds said:
Jim, this "center of the universe" and "the big bang is an expansion from a point" mistake is very common and is debunked here with great regularity. Continuing to insist that there is a center is a waste of time. Better you would accept the fact that you are wrong and then try to figure out why your logic is leading you astray. That way, you'll learn something. Continuing to believe there's a center, you'll learn nothing.

Phinds, thanks for your concern. I'm not trying to be closed minded about a center - in fact I'm very open-minded about physics. What I am concerned about is arguments that appear to be simply different points of view. I looked at your website and the 'balloon analogy' which is an example of my point. You are telling people there is 'no center' and 'no boundary' for the surface of the balloon - CORRECT! - for the analogy. But (and this is also a simple analogy) if you think of the balloon surface as 3-D residing on the surface of a 4-D sphere, then the center of the sphere is at coordinate (0,0,0,0). Or, if you take the view the balloon surface is 4-D; then the universe center could be at (0,0,0,0,0). There is no center for where we live (surface) but there is a center in a higher dimension. That's all I'm saying. The arguments seem to be over interpretation.
 
  • #39
Loren said:
The concept of a center assumes an outside to the universe, which is a falsehood. It's natural to want to think of it that way since we mentally like to look at problems by stepping outside of them, turning them in our virtual hands, and examining them from all sides. However, this mental abstraction is a false reality. You can't be outside the universe (except in a science fiction novel).

As far as then balloon analogy goes, if you consider the skin of the balloon or better yet, a sphere, as a 2D representation of the universe, where would it's absolute 2D center be?

Lauren, I actually agree with you. But let me ask you a question: do you accept the notion there can be higher dimensions to the universe beyond the ones which we live in and can actually access? If so, then in your example, we live on the 2D surface and there is no center. But in the 3D world (which flatland 2D people do not live in) the center of the 3D universe is (0,0,0).
 
  • #40
Loren said:
As far as then balloon analogy goes, if you consider the skin of the balloon or better yet, a sphere, as a 2D representation of the universe, where would it's absolute 2D center be?
First off, there is no centre to the surface of a balloon. Think about it. If you still think there is one, please calculate it for a sphere of , say, radius 10cm. You'll find that you won't be able to.
 
  • #41
Jim Hasty said:
Lauren, I actually agree with you. But let me ask you a question: do you accept the notion there can be higher dimensions to the universe beyond the ones which we live in and can actually access? If so, then in your example, we live on the 2D surface and there is no center. But in the 3D world (which flatland 2D people do not live in) the center of the 3D universe is (0,0,0).
I disagree completely. You are doing exactly what I warned about in the discussion of the balloon analogy. You are taking the analogy to places it just does not logically go, and more to the point you are trying to apply that to reality also in a way that just doesn't work. It is NOT a matter of interpretation. This is the last I'll have to say on the subject. Believe what you believe but don't expect physicists to agree w/ you.
 
  • #42
Jim Hasty said:
I looked at your website and the 'balloon analogy' which is an example of my point. You are telling people there is 'no center' and 'no boundary' for the surface of the balloon - CORRECT! - for the analogy. But (and this is also a simple analogy) if you think of the balloon surface as 3-D residing on the surface of a 4-D sphere, then the center of the sphere is at coordinate (0,0,0,0). Or, if you take the view the balloon surface is 4-D; then the universe center could be at (0,0,0,0,0). There is no center for where we live (surface) but there is a center in a higher dimension. That's all I'm saying. The arguments seem to be over interpretation.
Here is a direct quote from phind's ' the balloon analogy':
"The analogy is NOT intended to imply that our 3D universe is embedded in some 4D space (I’m not talking about 4D space-time but 4 dimensions of distance) "
Because I have nothing better to do, I counted, and in that article, it has been mentioned at least 4 times that there is no centre. There seems to be no contradiction.
 
  • #43
russ_watters said:
Latitude and longitude have an arbitrary reference at the prime meridian and equator, but that's not a center: Finite surface, no center.
[late edit]
And no edge either.

phinds said:
It is a trivial claim, as Russ has shown.

Loren said:
I agree, but a cube is a different story, so, the statement doesn't hold for all geometries.

with all due respect i believe you are too quick to shoot these things down and that you haven't paid close attention to the detail of what i said.

at the risk of coming off with a similar poor tone to these comments, allow me to explain in more detail so that it is not so easy to make the mistakes.

i quite explicitly defined what i imagine a laymen means by 'finite' - bounded in the dimensions of the coordinate system under consideration. in his ideals the surface of a sphere like you describe is an /infinite/ surface because in the local coordinate spaces there are no bounds unless you are choosing a chart that has a seam (singularity) on it rather than multiply wrapping around the sphere (e.g. a cylindrical projection) - in which case we now have a finite area /with well defined bounds in all coordinates/ and so we can use the layman's understanding of what a centre is and there very much is one at 0 latitude and longitude (assuming we go from -pi to pi, -1/2 pi to 1/2 pi).

with regards the cube you can map a cube to a sphere and a sphere to a cube (any convex geometry to a sphere) so using a cube makes no difference to the nature of this, nor a dodecahedron or a cylinder. it just introduces a deformed version of the same coordinate system.

the other point that people try to make is that with the balloon analogy it has volume, and the volume has a centre. comparing this to volume in the universe completely missing the abstraction the balloon analogy makes to simplify things - specifically using 2D as a substitute for 3D because people struggle with visualising and understanding 4D representations. in that sense, if the universe was an unbounded 3-sphere then we have a 'hypervolume' inside of it which also very much has a centre in that 'fictional' 4-space - note, that this 4-space is not a minkowski style space-time but a 'fictional' euclidean 4-space, in the same sense that the 3-space the balloon is embedded is not a 2,1 space-time, but euclidean 3-space - or alternatively an extension of the sphere's local coordinate system that replaces intrinsic curvature with extrinsic curvature by embedding the system in a space with higher dimensionality.

now, if i am wrong, and you can construct a reasoned argument for why instead of a flat statement asserting that these things are wrong and that i simply do not understand, then i will consider it and hope that i have the good graces adjust my stance accordingly if it is a convincing argument.

again i apologise if my tone is poor. its very frustrating to see these kinds of comments, they paint a poor picture of the scientific community to laypeople and they are not uncommon - i have been guilty of this my self plenty too. its a natural way to behave when you are confident in your knowledge and weary of trying to explain the same things repeatedly.
 
  • #44
Jim Hasty said:
Lauren, I actually agree with you. But let me ask you a question: do you accept the notion there can be higher dimensions to the universe beyond the ones which we live in and can actually access? If so, then in your example, we live on the 2D surface and there is no center. But in the 3D world (which flatland 2D people do not live in) the center of the 3D universe is (0,0,0).

We have nothing but some mathematical speculation of additional dimensions and those postulated may very well be so small as to be inaccessible. We can't prove the math is even correct.

You can't make a hypotheses based on pure mathematical speculation without testability.
 
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  • #45
UncertaintyAjay said:
First off, there is no centre to the surface of a balloon. Think about it. If you still think there is one, please calculate it for a sphere of , say, radius 10cm. You'll find that you won't be able to.

Of course. That was my point, too.
 
  • #46
Loren said:
Of course. That was my point, too.
Oops. Sorry. Must have misinterpreted that one. It's just that this is a very heated ' discussion', and I got a bit excited. haha
 
  • #47
Jheriko said:
with all due respect i believe you are too quick to shoot these things down and that you haven't paid close attention to the detail of what i said.

at the risk of coming off with a similar poor tone to these comments, allow me to explain in more detail so that it is not so easy to make the mistakes.

i quite explicitly defined what i imagine a laymen means by 'finite' - bounded in the dimensions of the coordinate system under consideration. in his ideals the surface of a sphere like you describe is an /infinite/ surface because in the local coordinate spaces there are no bounds unless you are choosing a chart that has a seam (singularity) on it rather than multiply wrapping around the sphere (e.g. a cylindrical projection) - in which case we now have a finite area /with well defined bounds in all coordinates/ and so we can use the layman's understanding of what a centre is and there very much is one at 0 latitude and longitude (assuming we go from -pi to pi, -1/2 pi to 1/2 pi).

with regards the cube you can map a cube to a sphere and a sphere to a cube (any convex geometry to a sphere) so using a cube makes no difference to the nature of this, nor a dodecahedron or a cylinder. it just introduces a deformed version of the same coordinate system.

the other point that people try to make is that with the balloon analogy it has volume, and the volume has a centre. comparing this to volume in the universe completely missing the abstraction the balloon analogy makes to simplify things - specifically using 2D as a substitute for 3D because people struggle with visualising and understanding 4D representations. in that sense, if the universe was an unbounded 3-sphere then we have a 'hypervolume' inside of it which also very much has a centre in that 'fictional' 4-space - note, that this 4-space is not a minkowski style space-time but a 'fictional' euclidean 4-space, in the same sense that the 3-space the balloon is embedded is not a 2,1 space-time, but euclidean 3-space - or alternatively an extension of the sphere's local coordinate system that replaces intrinsic curvature with extrinsic curvature by embedding the system in a space with higher dimensionality.

now, if i am wrong, and you can construct a reasoned argument for why instead of a flat statement asserting that these things are wrong and that i simply do not understand, then i will consider it and hope that i have the good graces adjust my stance accordingly if it is a convincing argument.

again i apologise if my tone is poor. its very frustrating to see these kinds of comments, they paint a poor picture of the scientific community to laypeople and they are not uncommon - i have been guilty of this my self plenty too. its a natural way to behave when you are confident in your knowledge and weary of trying to explain the same things repeatedly.

Thanks. No offense taken.

I was just pointing out that the broad statement made by Russ was perhaps a poor analogy. I think he adjusted his comment, so all is well.
 
  • #48
"After observing red-shifts of many stars, we can determine the orbit of our solar system about the milky way galaxy. By extending this for distant galaxies, in addition to observing the average Hubble expansion, we measure that our galaxy itself is not quite at rest with respect to the expanding universe. (Deep sky surveys show that galaxies are also arranged into larger structures, and that the pattern has no single "special" centre.)

So there is hard scientific evidence that the Earth is not the centre of the universe, let alone the sun or the galaxy even (though you might pedantically argue that the the Hubble Space Telescope satellite is at the centre of the observable universe). To put this another way, in light of modern cosmology: Can you tell me which city (or country) is at the centre of the globe?"
Quote from a 2008 PF post on " Does the Universe have a Centre." Note the " hard scientific evidence" part
 
  • #49
UncertaintyAjay said:
Here is a direct quote from phind's ' the balloon analogy':
"The analogy is NOT intended to imply that our 3D universe is embedded in some 4D space (I’m not talking about 4D space-time but 4 dimensions of distance) "
Because I have nothing better to do, I counted, and in that article, it has been mentioned at least 4 times that there is no centre. There seems to be no contradiction.
I fully agree with the article - as far as the analogy. THERE IS NO CENTER FOR THE SURFACE OF A BALLOON.
 
  • #50
Similarly, there is no centre for the Universe. Also, do read my last post. Scientific evidence and all that.
 
  • #51
Shouldn't science take both points of view with an open mind? Otherwise we choose a particular road and never look at other possibilities.
 
  • #52
Jim Hasty said:
Shouldn't science take both points of view with an open mind? Otherwise we choose a particular road and never look at other possibilities.
Occasionaly it happens that somebody comes up with a new theory which can explain some observations better than any existing paradigm.
In that case the new theory ought to be able to make some testable prediction which the old one does not, and if such testing verifies the prediction then the new theory will become considered as being more accurate.
However, there is no reason why 'alternative' theories should always be considered.
If an alternative theory doesn't explain anything any better than an existing theory does, it has no useful purpose.

There are often situations where some observed phenomena is not well explained by any particular theory, and when that is the case alternatives do get considered and tested for.
Dark matter for example is in that category, there are a number of proposals for what it might be, and various experiments ongoing in an attempt to determine if any of these are more likely, or whether some ideas can be discounted.
 
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  • #53
Is imagination the big problem here ? @phinds can you imagine/visualize the big bang and the universe in the way you describe it in your mind ? I understand the evidence suggests that that there is no centre and that all the galaxies are simply moving away from each other ,not from a particular point in space but i can't imagine/visualize the big bang in my mind ,perhaps it's simply because i never studied cosmology (i am not talking about balloon or any other analogy).
 
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  • #54
Monsterboy said:
Is imagination the big problem here ? @phinds can you imagine/visualize the big bang and the universe in the way you describe it in your mind ?
Absolutely. I think the problem is that you are trying to imagine it with a center. THAT I cannot do. Well, that's not quite true. I suppose I could imagine it in exactly the same way I imagine unicorns, but who cares?

I understand the evidence suggests that that there is no centre and that all the galaxies are simply moving away from each other ,not from a particular point in space
and in physics, that's what counts.

but i can't imagine/visualize the big bang in my mind ,perhaps it's simply because i never studied cosmology (i am not talking about balloon or any other analogy).
If you are going to try to visualize everything in quantum mechanics and cosmology, you are in for a lot of disappointment. What do you think a photon looks like, for example? You DO believe in photons, I assume?
 
  • #55
Jim Hasty said:
Shouldn't science take both points of view with an open mind? Otherwise we choose a particular road and never look at other possibilities.
It seems to me you are suggesting that we give equal credence to General Relative and the theory that the Earth is flat.
 
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  • #56
phinds said:
It seems to me you are suggesting that we give equal credence to General Relative and the theory that the Earth is flat.
I have avoided insulating you. Please give me the same courtesy.
 
  • #57
phinds said:
It seems to me you are suggesting that we give equal credence to General Relative and the theory that the Earth is flat.
It appears to me you prefer the 'flat earth' view and give no credence to GR.
 
  • #58
Jim Hasty said:
It appears to me you prefer the 'flat earth' view and give no credence to GR.
What?? That is just a juvenile attempt to get back at phinds.
The point he is trying to make is that you cannot reconcile two contradictory views by saying you are keeping an open mind. There is scientific evidence that shows the universe cannot have a centre, just as there is evidence that the Earth is not flat.
 
  • #59
Also, I found the same thing out when I joined PF a year ago. This is just how phinds is. All his replies are short and to the point. They sound rude, but they aren't meant that way.
 
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  • #60
rootone said:
Occasionaly it happens that somebody comes up with a new theory which can explain some observations better than any existing paradigm.
In that case the new theory ought to be able to make some testable prediction which the old one does not, and if such testing verifies the prediction then the new theory will become considered as being more accurate.
However, there is no reason why 'alternative' theories should always be considered.
If an alternative theory doesn't explain anything any better than an existing theory does, it has no useful purpose.

There are often situations where some observed phenomena is not well explained by any particular theory, and when that is the case alternatives do get considered and tested for.
Dark matter for example is in that category, there are a number of proposals for what it might be, and various experiments ongoing in an attempt to determine if any of these are more likely, or whether some ideas can be discounted.[/Q
 
  • #61
yes. But never were these theories wildly contradictory. If there is evidence that the universe does not have a centre, there isn't likely to ever be any evidence to the contrary.
 
  • #62
UncertaintyAjay said:
Also, I found the same thing out when I joined PF a year ago. This is just how phinds is. All his replies are short and to the point. They sound rude, but they aren't meant that way.
Haha... sorry. (1) I'm not a juvenile. But I meant what I said. (2) Phinds comes across to me as saying the universe exists in this surface of a balloon analogy. I TOTALLY DO SEE THE POINT. OK. I am not arguing that. But there are other good analogies. For example... (3) Suppose we live in the 'volume' and not the 'surface' of a sphere. If the universe sprang from a singularity at t=0; then our local universe could be a small sphere within the volume of a much larger sphere, which is all expanding outward from the singularity. The same effects of looking in any direction appears that all other galaxies are moving away from ours. (4) We can't see beyond our 'local universe' bounded by the local expansion which has reached the limits of the speed of light c. (5) I would be very much interested in some of the data which you mentioned that supports the concept of a centerless universe, if you would be so kind as to reference some. Thanks.
 
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  • #63
Jim Hasty said:
I have avoided insulating you. Please give me the same courtesy.
I did not mean it to be insulting. I am making the point that you are studiously avoiding the empirical evidence. That's what religious people do in many cases but it is not what scientists do.

At this point your unwillingness to be corrected leads me to believe that you are just trolling to see how far you can string us along in responding to your posts.

EDIT: I see our posts crossed. You ask for evidence. This "center of the universe" nonsense has, as I have already pointed out, been debunked here on this forum ad nausem. Do a forum search.
 
  • #64
About the singularity stuff. If the universe began as a singularity, the singularity was,at that instant, the entire universe. After that, the entire universe expanded. Every part. There was no part that did not, and hence there is no centre.
 
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  • #65
phinds said:
I did not mean it to be insulting. I am making the point that you are studiously avoiding the empirical evidence. That's what religious people do in many cases but it is not what scientists do.

At this point your unwillingness to be corrected leads me to believe that you are just trolling to see how far you can string us along in responding to your posts.

No, Phinds. I apologize; that is far from the truth about my intent. My hot button is people that reply to questions with an aire of "this is the way it is believe it or go away". And I apologize in advance for my next questions: (1) do you have any references to specific data (not analogies, but data) which supports a centerless universe? (2) What are your thoughts about a comparable analogy to the balloon surface - where instead of the universe being the surface, there are local universes which are spheres within a much larger universe? Has this been looked at and ruled out because of some supporting data?
 
  • #66
UncertaintyAjay said:
About the singularity stuff. If the universe began as a singularity, the singularity was,at that instant, the entire universe. After that, the entire universe expanded. Every part. There was no part that did not, and hence there is no centre.
The singularity is not expected to be manifested as an actual physical object, and is not fact included within the Big Bang theory.
It's just a name given to a condition of the Universe that we know nothing nothing about and maths can't help because it starts to produce nonsensical notions such as infinite density.
 
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  • #67
Jim Hasty said:
No, Phinds. I apologize; that is far from the truth about my intent. My hot button is people that reply to questions with an aire of "this is the way it is believe it or go away".
Fair enough. We DO see that here and I'm guilty of it sometimes, although I do normally attempt to explain things (as I did in this case) before I take that stance.

And I apologize in advance for my next questions: (1) do you have any references to specific data (not analogies, but data) which supports a centerless universe?
The Cosmological Principle, totally accepted in modern cosomology, requires a center-less universe because a center requires a preferred frame of reference.. As I suggested, do a forum search. As has already been pointed out in this thread alone, the red-shift evidence clearly says there is no center.
(2) What are your thoughts about a comparable analogy to the balloon surface - where instead of the universe being the surface, there are local universes which are spheres within a much larger universe? Has this been looked at and ruled out because of some supporting data?
I'm not the right person to ask about that since I think the whole "multiverse" concept is nonsense. Even if there IS a multiverse, however, it is not going to be spheres inside of a container. That ALSO has been discussed on this forum ad nausem.
 
  • #68
rootone said:
The singularity is not expected to be manifested as an actual physical object, and is not fact included within the Big Bang theory.
It's just a name given to a condition of the Universe that we know nothing nothing about and maths can't help because it starts to produce nonsensical notions such as infinite density.
Agreed, but the intent of his post was correct.
 
  • #69
phinds said:
Fair enough. We DO see that here and I'm guilty of it sometimes, although I do normally attempt to explain things (as I did in this case) before I take that stance.

The Cosmological Principle, totally accepted in modern cosomology, requires a center-less universe because a center requires a preferred frame of reference.. As I suggested, do a forum search. As has already been pointed out in this thread alone, the red-shift evidence clearly says there is no center.
I'm not the right person to ask about that since I think the whole "multiverse" concept is nonsense. Even if there IS a multiverse, however, it is not going to be spheres inside of a container. That ALSO has been discussed on this forum ad nausem.

Thanks. I am currently reading (again) your write up on the 'Balloon Analogy" - which I complement you on as very well written. I need to study more, but for now I do need confirmation on my understanding if you have time to answer, just to make sure I have this right. (1) My understanding now is that all bound systems do NOT expand. They may be bound on the small scale (quantum) or the large scale (gravitation): so this includes small molecules, solar systems, galaxies, clusters, and super clusters. (2) In the expansion of the universe the 'distances between bound systems is expanding'; but space-time, or the so called 'fabric of space' is NOT expanding. (3) This key for me. Empty space is simply the absence of matter it has no real properties of its own?
 
  • #70
Jim Hasty said:
Thanks. I am currently reading (again) your write up on the 'Balloon Analogy" - which I complement you on as very well written. I need to study more, but for now I do need confirmation on my understanding if you have time to answer, just to make sure I have this right. (1) My understanding now is that all bound systems do NOT expand. They may be bound on the small scale (quantum) or the large scale (gravitation): so this includes small molecules, solar systems, galaxies, clusters, and super clusters. (2) In the expansion of the universe the 'distances between bound systems is expanding'; but space-time, or the so called 'fabric of space' is NOT expanding. (3) This key for me. Empty space is simply the absence of matter it has no real properties of its own?
All of that is in accordance with my understanding, yes.

This "fabric of space" pop-science term causes LOTS of confusion. Unfortunately, Einstein himself used it but I don't think he really thought of space-time as something that bends/stretches/etc, it's just a felicitous term that sadly has lead to much confusion and leads non-science reporters to believe they have some understanding of what's going on.

EDIT: and thanks for the compliment on the article.
 
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