Proving that there is one center of the universe.

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  • #1
zeromodz
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I am attempting to prove with my understanding of physics that the universe must have a center. Here are my premises.

1) The universe is finite
The universe had a beginning and we know its expanding, so it cannot already by infinite in size

2) The universe is flat
The WMAP satellite measured microwave radiation proving that the universe is flat and not curved back onto itself.

3) Each observer has their own center of the universe and Hubble's sphere (accepted theory).

4) In theory if an observer could somehow take a wormhole or a way of transportation to make it to the end of his/her Hubble sphere, then his/her original radius is doubled.

5) This process can be repeated to infinity.

6) If each point in space is the center of the universe and space is expanding isotropically, then space must be infinite.

7) Space is not infinite due to premise 1.

8) The universe must have and end if its finite, therefore it must have a center in theory if it could be mapped out.


If the universe is finite, then it must have a quantitative amount of space. Having that said, we should theoretically be able to find an edge of space, since we know space is not curved back onto itself.
 

Answers and Replies

  • #2
rmalik
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and what do you propose would be past the edge?
 
  • #3
zeromodz
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and what do you propose would be past the edge?

Well, I don't know. That is probably the biggest mystery in my mind right now, but that is not the point. There has to be an edge.
 
  • #4
eachus
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I am attempting to prove with my understanding of physics that the universe must have a center. Here are my premises.

1) The universe is finite
The universe had a beginning and we know its expanding, so it cannot already by infinite in size
Alright so far....

2) The universe is flat
The WMAP satellite measured microwave radiation proving that the universe is flat and not curved back onto itself.
Oops! I think you misunderstood something. The issue of the curvature of space has/had to do with whether the universe was open or closed. More than enough matter to close the universe: positive curvature. Not enough matter to close the universe: Saddle-shaped. Just right? Flat.

The current belief is that the universe is exactly closed, which would mean that the universe would continue to expand, with the rate of expansion slowing. However, about 70% of the universe is dark energy, which apparently causes the expansion of the universe to accelerate. What is dark energy? Even more mysterious than dark matter.

As to the rest. I won't go into arguments about number of dimensions (10? 11? 40?), but the universe appears to be a hypersphere in at least four dimensions, including the ordinary dimensions of space. So, no matter which direction you go--if you can travel much faster than light--you will eventually return to where you started from.
 
  • #5
Chronos
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The universe is observationally and temporally finite, that does not mean it is provably finite in either respect. A wormhole would not solve this problem. You would still be unable to distinguish the edge from the center of whatever universe of destination.
 
  • #6
MotoH
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2
You would never be able to reach the edge, since space-time is not constrained by special relativity. So when you reach the old edge, the new edge is far, far away.
 
  • #7
curiouschris
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Well, I don't know. That is probably the biggest mystery in my mind right now, but that is not the point. There has to be an edge.

I have wondered about this as well. what defines the edge (if it exists).

A couple of things come to mind.
1/ everywhere light reaches is space.
2/ everywhere gravity effects is space

If the universe is expanding at less than the speed of light. What happens to light when it reaches "the edge"? my guess is there would be an infinite impedance mismatch. this would create a reflection (not just light but all energy).

The upshot of that is if we looked at the right place in the universe we may see our own reflection. It also begs the question. Is the universe is smaller than we think? Are we are stuck in some sort of hall of mirrors?

CC


P.S.
It saddens me the number of edge deniers out there. they must work for the oil companies or something.
 
  • #8
Ich
Science Advisor
1,931
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1) no
2) seems so
3) ok
4) Huh?
5) what process? (if I understood what you mean: you travel 1000 km a day. You can travel for as long as you want. Therefore earth's surface is infinite).
6) no
7) no
8) no

In our current model, the universee is spatially infinite. That doesn't mean that it really is infinite, but it certainly leaves the possibility.
Even if it were finite, there could be no border or center. Just as for points on the earth's surface.
 
  • #9
eachus
139
21
If the universe is expanding at less than the speed of light. What happens to light when it reaches "the edge"? my guess is there would be an infinite impedance mismatch. this would create a reflection (not just light but all energy).
There is no edge that light can reach. The balloon analogy is not good, but it is probably the best available. Think of an ant crawling on the surface of an inflating balloon. Even if the ant continues in a straight line, it will never get to an edge--or return to its starting location. So if there was an edge, it would be moving away from everywhere at faster than the speed of light.

Now imagine a hyperballoon in a hundred-dimensional manifold. When you start to inflate it, it chooses a few dimensions in which to expand and collapses in others. That is the inflationary period right after the big bang. The universe is still very small in the three space dimensions at the end of the inflationary period, but it was so rapid that light could not get from one part of the balloon's surface to any other. Even 13-14 billion years later, light still hasn't had time to get a significant fraction of the way around the balloon's surface. And it never will. (Yes, I know, light couldn't get far for the first few million years, until the universe cooled enough. But that is detail.)
It saddens me the number of edge deniers out there. they must work for the oil companies or something.
It is just the way the math works. If you want to get out of the universe, choose one of those rolled up dimensions, and move a few millionths of an inch in a straight line. ;-)
 
  • #10
zeromodz
246
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Alright so far....


Oops! I think you misunderstood something. The issue of the curvature of space has/had to do with whether the universe was open or closed. More than enough matter to close the universe: positive curvature. Not enough matter to close the universe: Saddle-shaped. Just right? Flat.

The current belief is that the universe is exactly closed, which would mean that the universe would continue to expand, with the rate of expansion slowing. However, about 70% of the universe is dark energy, which apparently causes the expansion of the universe to accelerate. What is dark energy? Even more mysterious than dark matter.

As to the rest. I won't go into arguments about number of dimensions (10? 11? 40?), but the universe appears to be a hypersphere in at least four dimensions, including the ordinary dimensions of space. So, no matter which direction you go--if you can travel much faster than light--you will eventually return to where you started from.


What are you talking about? If the universe is flat, you will never come back to the point where you started. That is in the closed universe model. I have done my research and have found no evidence supporting that the universe is closed back onto itself creating a never ending loop. Could you provide me with some?
 
  • #11
curiouschris
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The universe is still very small in the three space dimensions at the end of the inflationary period, but it was so rapid that light could not get from one part of the balloon's surface to any other. Even 13-14 billion years later, light still hasn't had time to get a significant fraction of the way around the balloon's surface. And it never will. (Yes, I know, light couldn't get far for the first few million years, until the universe cooled enough. But that is detail.)

All joking aside the above raised a couple of concerns, and sorry for the off topic stuff.

Firstly on my initial reading you seem to be saying that after the big bang the universe grew faster than the speed of light! Or perhaps you are saying it expanded at the speed of light?

Secondly as the universe cooled where did the heat go?

And on topic.

Isn't the centre of the universe the point of origin?
If the big bang didn't cause the universe to inflate in all directions at the same velocity then what constrained it? One would assume that the nothing that didn't exist outside of the singularity could not control the direction of the explosion/expansion. I know its an assumption, but one would assume the singularity itself would have been uniform in its singleness. If one could use such a phrase. So the expansion should occur in an even manner.

Only after matter started to coalesce would the universe take on a shape that appeared to be other than uniform. even then space itself should be uniform its just the visible universe that may appear ragged.

Lastly Why do cosmologists consider the universe to be an expanding balloon. what gives rise to that theory. in its simplest form that theory would indicate that the edge of the universe is just above our heads. and the edge of "inner nothing" is somewhere below our feet.

And sorry I am not a fan of explaining things away by calling it another dimension. that to me is the equivalent to the 'god of the gaps'. I.E. if you can't explain something throw in god, or in this case another dimension.

I much prefer to say we don't know just yet but we will get to that. otherwise its a case of making the maths fit the answer.

If the answer is 2 what's the question?
1+1 ?
no wrong its 1 + (dimension X)^(1/0) + 42 = 2

Just doesn't gel with me.

CC
 
  • #12
curiouschris
138
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I found an interesting article
http://curious.astro.cornell.edu/question.php?number=71 [Broken]

In essence it says each and everyone of us is the centre of the universe. that the universe is expanding in all directions at once. not from a single point like one would expect in an explosion. in other words space is expanding not the universe. it also says there is no 'edge' because the universe occupies everything everywhere.

At least that's how I read it. And I don't pretend to understand it.

CC
 
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  • #13
Chronos
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Correct, all observers are at the edge of their observable universe, All they see is their past.
 
  • #14
Hoku
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Do you think that dark flow could be a piece to this puzzle? Not only are these galaxy clusters moving against dark energy but they are all heading to the same spot - a point between the constellations Centaurus and Vela. Could these renegade clusters be heading for the center of our galaxy?

Perhaps the universe is a flat torus and these clusters are the first arrivals to make their way back to the center.

Perhaps our universe is one in a multiverse and these clusters are leaving the center of their universe and heading towards the center of ours.

Whatever the case, I think dark flow is a vital clue and evidence that there may be a center to our universe.
 
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  • #15
eachus
139
21
What are you talking about? If the universe is flat, you will never come back to the point where you started. That is in the closed universe model. I have done my research and have found no evidence supporting that the universe is closed back onto itself creating a never ending loop. Could you provide me with some?

Draw a circle on a piece of paper. If the paper is flat, there are 360 degrees to the circle. Or better, the circumference is Pi times the diameter. If the circumference is less than Pi times the radius, the paper is not flat. It might be the surface of a sphere. If the circumference is greater than Pi times the diameter, the paper is saddle-shaped.

This is the sense in which the universe is flat. (Well, when measured well away from black holes or some other source of gravity.)

Now let's look at space near a black hole. If, right at the event horizon you shine a beam of light in the right direction--it will hit you in the backside. If you ask the beam of light, it will tell you, that of course it went in a straight line--it doesn't know how to do anything else.

Hop in your superluminal space ship, fly straight ahead for long enough, and you will be able to talk to the light beam again, still going straight ahead--and around and around the black hole.

The problem/trick is that you can't separate the observer from the space he or she is embedded in. Lines which appear straight to those in the space can be understood to be curved by anyone outside that universe.
 
  • #16
eachus
139
21
Firstly on my initial reading you seem to be saying that after the big bang the universe grew faster than the speed of light! Or perhaps you are saying it expanded at the speed of light?
Much faster than the speed of light. The Inflationary epoch lasted much, much less than a second, and the universe inflated by a factor of at least 10^26 in length, width, and depth. (see: http://en.wikipedia.org/wiki/Inflation_(cosmology))
Secondly as the universe cooled where did the heat go?
See any physics or chemistry book and look up adiabatic expansion. If you want to think of the compressed hot universe doing work expanding the universe, fine. The net effect is that as the universe expands, and particles (including photons) move further apart, the measured temperature drops. You can also see this in cosmic red shifts.
Isn't the centre of the universe the point of origin?
Lol! But not at you. If the universe originated in some other universe, or multiverse, it is still at the same address. In fact, all the contents of the universe are still in that one point--in some other co-ordinate system, universe, set of dimensions, what ever you want to speculate existed before the big bang.
If the big bang didn't cause the universe to inflate in all directions at the same velocity then what constrained it? One would assume that the nothing that didn't exist outside of the singularity could not control the direction of the explosion/expansion. I know its an assumption, but one would assume the singularity itself would have been uniform in its singleness. If one could use such a phrase. So the expansion should occur in an even manner.
Get one of those long skinny balloons (again with the balloons! ;-) When you start to inflate it one section will suddenly start to grow. Then as you put more air in this section gets longer. The same sort of physics applies to dimensions right at the big bang. Once energy is going in to inflating (ouch!) some dimensions there is less pressure on others and they stay rolled up.
Lastly Why do cosmologists consider the universe to be an expanding balloon. what gives rise to that theory. in its simplest form that theory would indicate that the edge of the universe is just above our heads. and the edge of "inner nothing" is somewhere below our feet.
You have to keep track of the dimensions. We know that the universe is expanding in the three dimensions of space. Various string theories have additional dimensions and branes, etc. But that doesn't affect this discussion. The balloon is a two dimensional analogy of the three dimensional expansion of the universe. Forget that the balloon has three dimensions--the two-dimensions measured on its surface represents what happens to the three dimensions of the universe.

So the surface of the balloon is not under your feet in the x,y,z, or t dimension. But it will be in w or q or maybe 42. Now all you have to do is figure out how to take measurements in that dimension, and you too can have a Nobel prize.
 
  • #17
Hoku
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Obviously, the various different "big bangs" that would form a multiverse ARE in the same universe. I don't think the word is intended to be taken that literally. I'm neither for nor against the idea of a "multiverse", but it is an idea taken seriously by many professional cosmologists and dismissed by others.

http://www.newscientist.com/article/mg20126921.900-dark-flow-proof-of-another-universe.html

A multiverse would certainly work with the brane theory. But whether a multiverse is true or not was not the point of my post. My only point was that there are galaxy clusters moving against all the others and towards the same point in space. Be it from a multiverse, a 3-torus or whatever, the fact that this is happening suggests that there MAY be a center that they are moving towards.
 
  • #18
bannerman100
4
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Trying to respond to the original question:

Premise 2: surely means that space (not the universe itself) is "flat" or "linear" not "curved".

Premise 4: surely not doubled, only 1.5 x in a linear direction ?

Premise 5: Unless there is space beyond the edge of the universe, even given (way !) above lightspeed travel, you could only reach the edge of the expanding universe and follow its expansion at the speed of light.

(But then again, if you could outrun it, you would be increasing the expansion of the universe !)
(Or if you then exceed 2C, would you be going off in a little expanding bubble of space ? Creating another "universe" outside this one ?)

The Big Bang theory surely assumes that the universe originated from a definite point in space (even though it was the only point in space that existed at that instant)(and assuming that the Big Bang created all of what we now call space).

If the Big Bang emitted light from that instant, then the radius of the universe must be equal to the age of the universe multiplied by the speed of light (assuming the universe is expanding into nothingness, and is thereby creating more space (at a necessarily increasing rate) as it goes). Light from the Big Bang is progressively expanding the universe by continually creating more space (at the speed of light), and that light is continually creating the ever expanding "edge" of the universe.

Unless they've changed the theory without telling me, there is no space outside the universe. It must have an "edge", but doesn't have an "outside".

The centre of the universe must still be in the same place it started off, equidistant from all points on its spherically expanding outer perimeter.
(Assuming the light from the Big Bang expanded in all directions.) (There must be a very big dark hole there by now.)
(Mustn't there ?) ;)
 
  • #19
zeromodz
246
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Draw a circle on a piece of paper. If the paper is flat, there are 360 degrees to the circle. Or better, the circumference is Pi times the diameter. If the circumference is less than Pi times the radius, the paper is not flat. It might be the surface of a sphere. If the circumference is greater than Pi times the diameter, the paper is saddle-shaped.

This is the sense in which the universe is flat. (Well, when measured well away from black holes or some other source of gravity.)

Now let's look at space near a black hole. If, right at the event horizon you shine a beam of light in the right direction--it will hit you in the backside. If you ask the beam of light, it will tell you, that of course it went in a straight line--it doesn't know how to do anything else.

Hop in your superluminal space ship, fly straight ahead for long enough, and you will be able to talk to the light beam again, still going straight ahead--and around and around the black hole.

The problem/trick is that you can't separate the observer from the space he or she is embedded in. Lines which appear straight to those in the space can be understood to be curved by anyone outside that universe.

The question is, Is there enough matter in the universe to make space curve into an infinite loop as you just described with light in a black whole. If there is, shouldn't there also be enough mass to have a greater escape velocity then recessional velocity of the WHOLE universe?

This is why I am not convinced there is. If there is enough matter to curve space to trap the matter itself, it should surely have a greater escape velocity then recessional.
 
  • #20
Hoku
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Those that don't browse the "Cosmology" section of the forums might be interested to know that there is a current thread there discussing this very same topic entitled, "Center of the universe".
 
  • #21
Chronos
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Let's consider the CMB. If there were a 'center' of the universe, wouldn't the CMB appear significantly hotter in that direction compared to the opposite direction? This is not observed. You must be willing to assert we reside very near the 'center' of the universe to explain this anomaly.
 
  • #22
Cryptonic
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Let's consider the CMB. If there were a 'center' of the universe, wouldn't the CMB appear significantly hotter in that direction compared to the opposite direction? This is not observed. You must be willing to assert we reside very near the 'center' of the universe to explain this anomaly.

You said it!
 
  • #23
zeromodz
246
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Let's consider the CMB. If there were a 'center' of the universe, wouldn't the CMB appear significantly hotter in that direction compared to the opposite direction? This is not observed. You must be willing to assert we reside very near the 'center' of the universe to explain this anomaly.

That is actually very convincing to me. I am considering that your right. However, how do you deal with refuting my premises then?
 
  • #24
Hoku
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1) Do we have reason to believe we're NOT near the center?

2) Is it possible that our understanding of the CMB is incomplete? After all, the WMAP and the South Pole Telescope have recently discovered some anomalies and inconsistencies with it.

http://arxiv.org/abs/1001.4538

Can we really say that ANY part of cosmological theory is complete until we understand what things like dark energy, dark matter and dark flow are and where they come from?
 
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  • #25
curiouschris
138
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1) Do we have reason to believe we're NOT near the center?

I believe that it is assumed we are not the center of the universe for exactly the same reason it is assumed that everywhere in the universe is the same. In other words if we were in a very distant galaxy from our own and looked into the night sky we would see the same we are seeing now except in a different configurations. All other galaxies would be receding from us in exactly the same fashion as they do now. this I believe is called the "The Cosmological Principle".

I find it incredulous that we use that as a basis for cosmology. We have as far as I am aware no way to actually prove it. I do admit it is very seductive, If its not that way then its also difficult for us to make any other deductions about the universe. It's also a problem that if scientists were to conclude we were be at the centre of the universe then certain theological arguments will follow. That would cause a problem for some scientists.

It would seem to me If the CMB was to ring us equally in all directions (which it does) and if we did not apply the cosmological principle, then it may well be we are at the centre of the universe.

CC
 
  • #26
Chronos
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It seems unlikely earth [and the local cluster] would be moving relative to the CMB if we reside at the center of the universe.
 
  • #27
curiouschris
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It seems unlikely earth [and the local cluster] would be moving relative to the CMB if we reside at the center of the universe.

Are we? I read that "The cosmic microwave background is isotropic to roughly one part in 100,000"

Please correct me if I am wrong, doesn't that mean its the same (or near enough) in all directions?

source: http://en.wikipedia.org/wiki/Cosmic_microwave_background_radiation

CC
 
  • #28
Hoku
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The real question isn't whether or not our galaxy cluster is at or near the center of the universe. The question is whether or not there IS a center of the universe in the first place. This is obviously a very difficult question to answer. The answers that most of us agree on are based on a universe in which spacetime is emergent. However, if we consider that spacetime is absolute ( http://www.springerlink.com/content/k0htmwr32m4wd7kv/fulltext.pdf?page=1 ), then we find very different answers to the question.

Let's say spacetime is absolute and in the shape of, not a sphere but a ball. This way we can preserve flat and finite qualities of spacetime. If the size of this spacetime remains fixed then we can view expansion in a much simpler way. If the matter of the big bang originated, not from the center of spacetime, but at the edge, then it is expanding towards the widest part of the ball (spacetime). In this case, dark energy may be a property of spacetime itself. If spacetime were to have a movement constant, such that matter must traverse spacetime at a constant speed, then matter would not only be moving farther away from each other as it approached the center of spacetime but it would HAVE to be doing it at an increased speed to satisfy the "movement constant".

In this scenario, we cannot say that "the universe is expanding". We can only say that all of matter is moving farther away from every other bit of matter. This is because the universe contains both spacetime and matter but the spacetime portion of it would not be expanding. In this scenario, there are two "centers". One is the center of spacetime itself and the other is of the center of the expanding matter within it. The originating point of the big bang may be different from each of those centers.
 
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  • #29
eachus
139
21
Are we? I read that "The cosmic microwave background is isotropic to roughly one part in 100,000"

Please correct me if I am wrong, doesn't that mean its the same (or near enough) in all directions?

source: http://en.wikipedia.org/wiki/Cosmic_microwave_background_radiation

CC

Did you read the Wikipedia article at the link you posted? "Raw CMBR data coming down from the space vehicle (i.e., WMAP) contain foreground effects that completely obscure the fine-scale structure of the Cosmic Microwave background. The fine-scale structure is superimposed on the raw CMBR data but is too small to be seen at the scale of the raw data. The most prominent of the foreground effects is the dipole anisotropy caused by the Sun's motion relative to the CMBR background. The dipole anisotropy and others due to Earth's annual motion relative to the Sun and numerous microwave sources in the galactic plane and elsewhere must be subtracted out to reveal the extremely tiny variations characterizing the fine-scale structure of the CMBR background."

In other words, once the effects of the sun's motion relative to the CMB, the Earth's motion around the sun, etc., etc. are subtracted out, the CMB is very uniform. Note that we can make guesses as to what the various components of the sun's motion relative to the CMB are. (Motion around the galactic center, the Milky Way's motion relative to the rest of the local cluster, etc.) But the value that is subtracted out of the CMB (dipole moment) is used in effect to measure the total motion of the sun, rather than computing it from other data. The Earth's motion, and the satellite's motion relative to the Earth are more complex, and there the known velocities are used.

When you look at the dipole signal, it implies that the sun--and everything in the local cluster--is moving toward a giant attractor outside the visible section of the universe. Most scientists think that when we get a better handle on where the dark matter is in the local cluster, it will "explain away" the giant attractor. But it is going to take years to get good maps of the dark matter in the Milky Way, and longer to get maps for the local cluster.

Notice that I am not advocating the existence of a giant attractor. We know the dark matter is there. We know it has gravitational effects on visible matter, and we know it is lumpy on the scale of galaxy clusters from gravitational lensing events. But we have no idea how the local dark matter is distributed.
 
  • #30
Hoku
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Some of you might be interested in a new article that came out last night. http://news.discovery.com/space/dark-flow-universe.html

The article describes new discoveries about dark flow (I mentioned dark flow on post #14 of this thread). Now, instead of only a select few clusters moving in this direction, they are suggesting that ALL clusters are moving in this same direction. This means that all of matter is, together, moving from one point to another. Keep your eye out for the March 20 issue of The Astrophysical Journal Letters. This is where the official idea is being published.

I know I've already been scolded for coming up with ideas in the forums, but this new discovery certainly does support the idea I suggested in my last post of this thread.
 
  • #31
curiouschris
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The real question isn't whether or not our galaxy cluster is at or near the center of the universe. The question is whether or not there IS a center of the universe in the first place.

You can't ask the question is there a centre of the universe? Without asking the question, where? in other words to prove there is a centre of the universe you have to point at it.

My mention of the CMBr is just to say if its equal in all directions then perhaps we are at the centre. I also realise that like a fog that totally envelopes you, it appears consistent in all directions, but the fog itself tricks us into that by preventing us from viewing further.

The dark flow theory you mention assumes the universe has "bounds" that something outside those bounds could exert a force on it. perhaps it just indicates the universe is much much larger than previously thought and that galaxies tend to cluster together so that what we see as our complete universe is nothing more than a cluster of galaxies within the overall universe and that there are other clusters of galaxies throughout a real universe that is trillions of times larger than the one we can measure.

In other words our big bang was just a violent event in a universe that is full of similar violent events.

If our telescopes allowed us to see only as far as the edge of the milky way. that beyond that was nothing that we could see, or even imagine. we would assume that the milky way was the entire universe. and ponder the strange questions that arise from that postulation.

Then some bright spark invents a new more sensitive telescope that reveals the other galaxies and not just one, an immeasurable number of them. That moment in time might be coming to us where we realise our cluster of galaxies is but one of an immeasurable number of similar clusters.

CC
 

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