# Thread: A Rotating Universe

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## A Rotating Universe

If the whole universe were rotating with respect to the central axis of the universe wouldn't this "look" the same as if the universe were radially expanding explosively from a single point?

Both scenarios represent motion, one radial and the other tangential, which would cause the light from distant sources to be red-shifted due to time dilation.

One would be transverse red-shifting (rotating scenario) and the other would be doppler-like red-shifting (radially expanding scenario).

Without any extra-universal (outside the universe) reference points we could not tell if the universe were rotating except by following a similar train of thought as done in this post: The Fastest Clock.

If the universe were rotating as a whole and it were contracting then, due to conservation of angular momentum, the respective tangential velocities of the galaxies would increase which would cause the source-redshift to increase which would imitate an expanding radial universe because it would seem that since the redshift is increasing then the objects must be accelerating away ...

... but in reality the universe is collapsing.

This thread is now open for discussion.

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How can something without a center rotate?

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## Cosmological Principle

Originally Posted by BISMARCK
How can something without a center rotate?
The cosmological principle states that the center of expansion is no where specific and so everyone can be considered the center of their universe.

But the universe is a finite size/age which means the universe has size dimensions therefore it must have a center.

4. Originally Posted by Squashed
But the universe is a finite size/age which means the universe has size dimensions therefore it must have a center.
Was that a question, or an assertion?

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Originally Posted by Squashed
If the whole universe were rotating with respect to the central axis of the universe wouldn't this "look" the same as if the universe were radially expanding explosively from a single point?
A rotating universe was one of Newton’s ideas about how the universe could keep from collapsing due to all the gravity within it.

Turns out he was right on the small scale. This is how rotating galaxies stay together.

If the whole universe rotated so much that we would notice the same redshifts we see now, we would see them only in the form of a disk area around the axis of the universe, since the ones near the axis and along the axis would not be moving away from each other so fast. In other words we would have a disk universe, not a spherical universe. A rapidly rotating sphere would turn into a disk. We don’t see a disk universe when we look out, we see a sphere universe, so far.

Of course, if it’s very much bigger than we think it is, it could be doing all sorts of things that we don’t yet know about.

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Originally Posted by Squashed
The cosmological principle states

The cosmological principle is a guess, an idea, a "belief", a postulate. It is not a "known fact."

7. ## Oh Yeah?

Originally Posted by Squashed
But the universe is a finite size/age which means the universe has size dimensions therefore it must have a center.
The surface of a sphere is definitely finite. Where is its center?

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Originally Posted by Tim Thompson
The surface of a sphere is definitely finite. Where is its center?
It's on the inside of the sphere. Like, you know, the center of the earth is inside the earth.

9. Rotation can only be said to take place if there is another point of reference.
As far as the universe is concerned no such point exists. The question makes no sense.

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Originally Posted by Occam
Rotation can only be said to take place if there is another point of reference.
As far as the universe is concerned no such point exists. The question makes no sense.
You mean, I can’t move unless I can see some other point of reference?

Two rockets pointed in different directions at the two ends of a long metal beam can’t rotate the beam unless someone sees “another point of reference”? I don’t believe that.

11. Originally Posted by Sam5
You mean, I can’t move unless I can see some other point of reference?

Two rockets pointed in different directions at the two ends of a long metal beam can’t rotate the beam unless someone sees “another point of reference”? I don’t believe that.
No. Seeing it is irrelevant. It has to be there, though. In this case, since the universe is the only thing, there being nothing outside of the universe in our accepted model, how can it be said to rotate? Parts of it move relative to other parts, but it is not possible to say the universe en masse rotates

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## Example

Originally Posted by Occam
No. Seeing it is irrelevant. It has to be there, though. In this case, since the universe is the only thing, there being nothing outside of the universe in our accepted model, how can it be said to rotate? Parts of it move relative to other parts, but it is not possible to say the universe en masse rotates
grav raised an interesting scenario over in the ATM*** section with a quote in this post.

I clarified the situation in this post: Interesting Observation.

We have the earth rotating and a geostationary orbiting satellite - we, of course, know that the system is rotating but if that "small" system is put into empty space without reference points then how do we know it is rotating?

Does rotation simply cease when reference points are lost?

If this is true then velocities would cease when reference points are lost (rotation is a directionally changing tangential velocity).

The light in a light-reflection clock always "knows" when motion is present, beit linear velocity or rotational velocity - look to the light.

*** - I know I shouldn't look in that section but curiosity always drives me to read the material presented over there.

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Originally Posted by Sam5
It's on the inside of the sphere. Like, you know, the center of the earth is inside the earth.
Sam5 So you are saying that if we run a video of the Big Bang backwards, the spherical isotropic distribution we see now would all collect into one relatively small spherical body...is that it? Pete.

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Originally Posted by trinitree88
Sam5 So you are saying that if we run a video of the Big Bang backwards, the spherical isotropic distribution we see now would all collect into one relatively small spherical body...is that it? Pete.
When I first started investigating the Big Bang theory, back in the early ‘90s, I called Mt. Wilson Observatory and I talked to professional astronomer Robert Jastrow. He said in a book that the universe started out as a small round thing. I asked him on the phone about how small did he think this small round thing was. He said, “About the size of a basketball.”

Here’s a quote from his book, “Until The Sun Dies”:

“Many more measurements have been made on Palomar
Mountain and elsewhere, down to the present day, and no excep-
tion has been found to the rule discovered by Slipher. Regardless
of the direction in which we look out into space, all the distant ob-
jects in the heavens are moving away from us and from one
another. The Universe is blowing up before our eyes, as if we
are witnessing the aftermath of a gigantic explosion.
Consider the implications of this picture. If the galaxies are
moving apart, at an earlier time they must have been closer
together than they are today. At a still earlier time, they must
have been still closer together. Continue to move backward in
time in your imagination; the outward motions of the galaxies,
reversed in time, bring them closer and closer; eventually, they
come into contact; then their materials mix; finally, the matter of
the Universe is packed together into one dense mass under enor-
mous pressure, and with temperatures ranging up to trillions of
degrees. The dazzling brilliance of the radiation in this dense,
hot Universe must have been beyond description. The picture,
suggests the explosion of a cosmic hydrogen bomb. The instant
in which the cosmic bomb exploded marked the birth of the Uni-
verse.”

15. For our universe to be rotating, I would think it would require something to be rotating in, such as another dimension. While I am personally intrigued with this concept, there is as yet no evidence of any additional dimensions. CERN may be making some new discoveries once they switch on their new accelerator some time later this year. Exciting times lay ahead!

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Originally Posted by Occam
No. Seeing it is irrelevant. It has to be there, though. In this case, since the universe is the only thing, there being nothing outside of the universe in our accepted model, how can it be said to rotate? Parts of it move relative to other parts, but it is not possible to say the universe en masse rotates
If the universe is small enough and if it rotates, we should see it as being disk shaped, just as we see our galaxy as being disk shaped. We don't need to see anything outside of our galaxy (and there doesn't need to be anything outside of our galaxy) for us to realize that our galaxy rotates. The rotation sets the general shape of our galaxy, whether there is anything outside it or not.

There is no evidence of our universe rotating, based on what we see now, because what we see now is redshifts of the distant galaxies in all directions, and the redshifts are even all around our spherical view, from our point of view, so as it looks from our point of view right now, the universe looks spherical, indicating that it is expanding outward in all directions, and suggesting that it is not rotating.

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Originally Posted by jamini
For our universe to be rotating, I would think it would require something to be rotating in, such as another dimension.
It is in space. It could be rotating in space with no other "dimensions" required.

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## Spherical Red-Shifting

Originally Posted by Sam5
...
Here’s a quote from his book, “Until The Sun Dies”:

“Many more measurements have been made on Palomar
Mountain and elsewhere, down to the present day, and no excep-
tion has been found to the rule discovered by Slipher. Regardless
of the direction in which we look out into space, all the distant ob-
jects in the heavens are moving away from us and from one
another. The Universe is blowing up before our eyes, as if we
are witnessing the aftermath of a gigantic explosion.
Consider the implications of this picture. If the galaxies are
moving apart, at an earlier time they must have been closer
together than they are today. At a still earlier time, they must
have been still closer together. Continue to move backward in
time in your imagination; the outward motions of the galaxies,
reversed in time, bring them closer and closer; eventually, they
come into contact; then their materials mix; finally, the matter of
the Universe is packed together into one dense mass under enor-
mous pressure, and with temperatures ranging up to trillions of
degrees. The dazzling brilliance of the radiation in this dense,
hot Universe must have been beyond description. The picture,
suggests the explosion of a cosmic hydrogen bomb. The instant
in which the cosmic bomb exploded marked the birth of the Uni-
verse.”
Yes, that is correct about the spherical nature of the red-shifting which leaves only one conclusion radial motion away from the observer (us).

I guess my mind got carried away by grav's analogy.

But it is a good mind exercise considering how we could tell a rotating universe from an "exploding" universe (got to put a good spin on this thread somehow).

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Originally Posted by Squashed
Yes, that is correct about the spherical nature of the red-shifting which leaves only one conclusion radial motion away from the observer (us).

I guess my mind got carried away by grav's analogy.

But it is a good mind exercise considering how we could tell a rotating universe from an "exploding" universe (got to put a good spin on this thread somehow).

Of course. I love good mind exercises. They keep me from going senile.

20. Originally Posted by Sam5
It is in space. It could be rotating in space with no other "dimensions" required.
So you are suggesting that space is some type of container and the stars, galaxies, etc. are the contents of that container?

If so:

• Does the container have boundries?

• What (if anything) is outside of the container?

If not, what is our universe spinning or rotating relative to?

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Originally Posted by jamini
So you are suggesting that space is some type of container and the stars, galaxies, etc. are the contents of that container?

If so:

• Does the container have boundries?

• What (if anything) is outside of the container?

If not, what is our universe spinning or rotating relative to?
Nobody can answer those questions, because we can see only so far out and not farther. We can only guess about what is out there beyond where we can see.

But we do know that our solar system is in space, our galaxy is in space, and all we can so-far see of the universe is in space, so I suspect what is way out there is more space. At least, all we can now see is stuff in space.

22. I just can’t find the value in adopting a spinning universe theory. It seems to pose more questions than it purports to answer. Wouldn’t conservation of angular momentum demand some evidence if we are in the expansion phase? If there is, I am not aware of anything that may account for it.

I guess my main problem is still with the boundaries. What is between the space that is spinning and the space that is not? Where do we make the distinction?

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## Just a Thought

Originally Posted by Sam5
If the universe is small enough and if it rotates, we should see it as being disk shaped, just as we see our galaxy as being disk shaped. ...
Just had a thought that there are galaxies that are spherical shaped which would suggest that any rotation is not about a common axis to cause a disk shape - not that this knowledge could salvage a rotating universe idea (could it?).

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Originally Posted by jamini
I just can’t find the value in adopting a spinning universe theory. It seems to pose more questions than it purports to answer. Wouldn’t conservation of angular momentum demand some evidence if we are in the expansion phase? If there is, I am not aware of anything that may account for it.

I guess my main problem is still with the boundaries. What is between the space that is spinning and the space that is not? Where do we make the distinction?

I don't think anyone is suggesting that we live in a rotating universe. The question was posed as a "what if" question.

25. Originally Posted by Sam5
There is no evidence of our universe rotating, based on what we see now, because what we see now is redshifts of the distant galaxies in all directions, and the redshifts are even all around our spherical view, from our point of view, so as it looks from our point of view right now, the universe looks spherical, indicating that it is expanding outward in all directions, and suggesting that it is not rotating.
If the redshifts are even all around our spherical view then wouldnt that suggest that from our point of view that we are at the center?

The only perspective i can think of to be able to see everything moving away from you is to be in the center of it all. Any place else and some objects would seem to be still and others moving toward you wouldnt it?

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Originally Posted by daxloves
If the redshifts are even all around our spherical view then wouldnt that suggest that from our point of view that we are at the center?
That would be true if the last deep field photos taken by Hubble showed ALL the universe and ALL the MOST DISTANT galaxies in the universe. But those photos don’t show that. They showed the most distant galaxies that Hubble could see at that time. A future larger space telescope will most likely be able to see deeper into the universe and out farther and will see more galaxies that we can see right now.

This is much like it was before people had any telescopes at all and could only see about 5 to 10 light years (or whatever) into our own galaxy. What those people saw was a “circle” of stars around the earth and that circle was called the Milky Way. Some people thought that was the “whole universe”, but it wasn’t.

Later, people invented telescopes and then bigger telescopes, and early in the 20th Century astronomers began to realize that we were seeing deeper into a very large spiral galaxy. Today we know the spiral galaxy is about 100,000 light years in diameter. We are located about 30,000 from the center and about 20,000 from an outer edge.

Ok, so, we will have to wait until much later, when bigger telescopes are built, before we can tell where we are inside our big universe. Seeing the “sphere” that we seen now is only seeing our “sphere of visibility”, which might be quite small when compared to the size of the whole universe. Just like when people could see the small “ring” of the Milky Way, which was quite small when compared to our entire galaxy.

Here’s a crude picture I drew to show what I’m talking about.

http://tinypic.com/k18d2r.jpg

The circle represents our current “sphere of visibility”. The dot in the center of the circle is us. But, since the universe is bigger than our “sphere of visibility”, we don’t know where we are located inside the whole universe. There are some theories that say the whole physical universe is now “infinite”. But, personally, I don’t know how big it is.

Originally Posted by daxloves
The only perspective i can think of to be able to see everything moving away from you is to be in the center of it all. Any place else and some objects would seem to be still and others moving toward you wouldnt it?
Every galaxy inside that “sphere of visibility” is moving away from every other one, and each would see the others moving away, so the fact that all the distant ones that we can see are moving away doesn’t mean we are in the center of the expansion. We are just somewhere within the whole universe, and everything that we can see (outside of the small local group) are moving apart. Any galaxy inside that circle that I drew would see pretty much the same thing as we see, which is all the distant galaxies moving away.

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Originally Posted by daxloves
If the redshifts are even all around our spherical view then wouldnt that suggest that from our point of view that we are at the center?
Ok, here’s what we’ve got to look for in the future:

If the universe is a true sphere which has a radius of two to three times the radius of our telescopic “sphere of visibility” in the future. Then if we are approximately located within the universe about where we are located inside our galaxy, in other words, far from the center and also a long way from an outer edge, but closer to the edge than the center, then this is what we should see:

http://i15.tinypic.com/2w4mez6.jpg

Again, the circle is our “sphere of visibility”. We are in the center of that sphere. But note that as our telescopic view increases in distance, as we invent bigger telescopes, the drawing illustrates how we could some day see an outer “edge” (to the right of the drawing) with no more galaxies beyond that “edge”. But when we look in the opposite direction, we see no outer “edge” because we are looking through our full universe in the direction of the center.

So, if we ever do discover an outer “edge” and it is in just one part of the sky, and in the opposite direction we don’t see any outer “edge”, that will mean we have discovered the outer “edge” of our universe that we are closest too. We might even then be able to calculate how big the universe actually is.

This is similar to why one side of our Milky Way is not as dense as the other side. The less dense side is the side toward the outer “edge” of our galaxy, and the more dense side is the side in the direction of the “center” of our galaxy.

If we eventually see an outer edge in all directions, then uh oh, that might mean we are in the center of the universe. But I don’t expect that that’s what we will see. I think that future deep field views might possible show less distant galaxies in one direction, and more distant galaxies in the opposite direction. So, then, we would be seeing outside our universe, or at lest to one part of the most outer edge of galaxies in one direction, and we would be seeing deep within (toward the center) in the opposite direction. I was hoping we would see this during my lifetime, but I don’t think we will. It might take another 50 or 100 years or more before we see anything like this.

Of course if the universe has expanded to an “infinite” size by now, then we won’t ever be able to see an outer edge in any direction we look.

28. The reason galaxies rotate is because during their expansion, they were affected by another's gravity. They way the universe is, expanding in all directions, it is not possible for it to rotate, unless one section passes, say the gravity of another universe. Then it will pull the matter and begin a spin. But you need a lot of matter for the universe to rotate.

29. Originally Posted by BISMARCK
How can something without a center rotate?
A basketball has no center and rotates.

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