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What are the explanations for greater than C space-time expansion?

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Neither time nor space is being created... the geometric volume of space simply increases. One of the most common mistakes is to try and define space with some fabric like property. Space itself has no energy or fabric. It is a geometric volume that is simply filled with the energy-mass from the rest of the universe.

 

That being said the superluminal velocity measurements of expansion is a consequence of the separation distance and the Hubble flow.

 

Hubble's law. The greater the distance the greater the recessive velocity.

 

[latex]V_{recessive}=H_Od[/latex] the subscript o meaning the hubble parameter today, which is constant only in time..meaning at a particular time Its not a constant as per se

 

a consequence of Hubble's law is that when recessive velocity becomes greater than the speed of light, this region is described as the Hubble radius or sphere.

 

However the recessive velocity is not an inertial velocity hence as mentioned, as only the volume is increasing and expansion is not a consequence of inertia, GR and SR do not apply.

This recent article written by a physicist friend of mine, covers this in excellent and well written detail. With very little math involved as his target audience is the general public

 

http://tangentspace.info/docs/horizon.pdf :Inflation and the Cosmological Horizon by Brian Powell

this is another good article

http://arxiv.org/abs/astro-ph/0310808 :"Expanding Confusion: common misconceptions of cosmological horizons and the superluminal expansion of the Universe" Lineweaver and Davies


We

 

Also there is an error in your question: we cannot see anything going faster than light. The point beyond which galaxies are receding faster than light is called the "horizon" and we can see nothing beyond it.

This is incorrect we can see farther than the Hubble sphere, Much farther. We can measure recessive velocities at z=1080 at around 3c. See the first article I posted to see why.


I agree that it is VERY misleading. You have explained why it is misleading.

Now it remains to explain clearly what the expansion of space means.

If a volume of space is simply a filled region, it means, as I naively understand, that when space expands there is a larger volume of space with more stuff inside it.

Not that anything else happens.

correct

Edited by Mordred

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(...)

correct

If my statement is correct, by which way do we observe "stuff" receding?

Because observation is about "stuff", not about space. IOW we do not observe space expanding. What we do observe is stuff receding. How can you reconcile all of this?

Edited by michel123456

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If my statement is correct, by which way do we observe "stuff" receding?

Because observation is about "stuff", not about space. IOW we do not observe space expanding. What we do observe is stuff receding. How can you reconcile all of this?

 

The volume increases everywhere. So any two points have to be further apart after the volume increases, which looks exactly like they are moving apart.

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The volume increases everywhere. So any two points have to be further apart after the volume increases, which looks exactly like they are moving apart.

That is scaling.

It works only if the "points" are mathematical points, with dimension zero.

 

If the "points" are 3d objects, the objects are scaled as well and they do not observe any change, no volume increase.

 

Or it is the other wayout, and you must consider that the 3d objects are shrinking: then yes they will observe a relative "volume increase" even if the volume remains the same.

 

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The standard explanation is that while space expands, 3d objects do not expand because they are gravitationaly bound.

So it means that space has a powerful hand able to transport the 3D objects at their new location from scaling, but that same hand is too weak to provoke a scaling of the object itself.

I cannot swallow that.

 

What I could swallow is the following:

Scaling does happen, we are scaled continuously, and because we are looking constantly into the past, what we are observing in the past has another scaling factor than the one we have today.

That would make sense.

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That is scaling.

It works only if the "points" are mathematical points, with dimension zero.

 

If the "points" are 3d objects, the objects are scaled as well and they do not observe any change, no volume increase.

I'm not seeing why this is the case within the context of the model. 3D objects do not expand or add volume, space does.

 

 

Or it is the other wayout, and you must consider that the 3d objects are shrinking: then yes they will observe a relative "volume increase" even if the volume remains the same.

 

--------------

The standard explanation is that while space expands, 3d objects do not expand because they are gravitationaly bound.

So it means that space has a powerful hand able to transport the 3D objects at their new location from scaling, but that same hand is too weak to provoke a scaling of the object itself.

I cannot swallow that.

Why is transportation necessary for this to happen? The model says there is no actual motion, which is a local effect only. It seems that your objection to the model is that it doesn't work in a way it never claims to work.

 

 

What I could swallow is the following:

Scaling does happen, we are scaled continuously, and because we are looking constantly into the past, what we are observing in the past has another scaling factor than the one we have today.

That would make sense.

I believe there's already a thread for that discussion.

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I'm not seeing why this is the case within the context of the model. 3D objects do not expand or add volume, space does.

 

 

 

Why is transportation necessary for this to happen? The model says there is no actual motion, which is a local effect only. It seems that your objection to the model is that it doesn't work in a way it never claims to work.

 

 

 

I believe there's already a thread for that discussion.

That means either I or you do not understand what happens when scaling occurs.

 

I will open a new thread about scaling.

Edited by michel123456

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That means either I or you do not understand what happens when scaling occurs.

 

I don't think that's the issue. The model doesn't say it's an issue of scaling. As I said, it seems that your objection is to something that's not part of the model; it doesn't work the way you want it to work, but that's not an issue with the model.

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I'm not seeing why this is the case within the context of the model. 3D objects do not expand or add volume, space does.

 

 

 

Why is transportation necessary for this to happen? The model says there is no actual motion, which is a local effect only. It seems that your objection to the model is that it doesn't work in a way it never claims to work.

 

 

 

I believe there's already a thread for that discussion.

But there is a change of position. When we observe galaxies receding from us, I suppose you cannot say that they do not change position.

Simply this change of position is not the result of proper motion but caused by the expansion of space. Isn't that what the model says?

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But there is a change of position. When we observe galaxies receding from us, I suppose you cannot say that they do not change position.

Simply this change of position is not the result of proper motion but caused by the expansion of space. Isn't that what the model says?

 

Yes, the motion is cause by the expansion of space. There is no expansion of objects. This is not scaling.

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But there is a change of position. When we observe galaxies receding from us, I suppose you cannot say that they do not change position.

Simply this change of position is not the result of proper motion but caused by the expansion of space. Isn't that what the model says?

 

The relative motion of (distant) galaxies is not due to their motion through space. Consider a simple example of a 3D grid of points. If you put galaxies at fixed points within the grid and then allow the grid to expand, then those galaxies will all get further apart (at a rate proportional to how far apart they are) even though they do not change their position in the grid.

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The relative motion of (distant) galaxies is not due to their motion through space. Consider a simple example of a 3D grid of points. If you put galaxies at fixed points within the grid and then allow the grid to expand, then those galaxies will all get further apart (at a rate proportional to how far apart they are) even though they do not change their position in the grid.

Yes, the grid has been scaled.

And the points on the grid aren't.

 

But when the grid expands, there is a change in position.

------------------------

And as I said before (with the feeling I am talking to a wall)

The same exact effect is obtained when you keep the grid as it is, and shrink the points.

 

Exactly in the same way with relativity of motion where you cannot know who is moving and who is standing at rest, the same relative effect can arise from scaling.

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But when the grid expands, there is a change in position..

 

It depends on what you mean by "position". I am proposing a thought experiment where the galaxies are fixed to the grid so if a galaxy is at the (xyz) position (3,4,5) on the grid, then it will still be at the same coordinates after you stretch the grid. However, because the grid is stretched, that galaxy will now be further away from the point (2,3,4). Therefore, from the point of view of the people in each galaxy, there relative position has changed.

 

 

The same exact effect is obtained when you keep the grid as it is, and shrink the points.

 

Yes, you can choose a different set of coordinates where that is true. In reality, it is more complex (you have to deal with the speed of light and other physical constants changing) and, for most people, less intuitive.

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Yes, the grid has been scaled.

And the points on the grid aren't.

 

But when the grid expands, there is a change in position.

------------------------

And as I said before (with the feeling I am talking to a wall)

The same exact effect is obtained when you keep the grid as it is, and shrink the points.

 

Exactly in the same way with relativity of motion where you cannot know who is moving and who is standing at rest, the same relative effect can arise from scaling.

 

But the "points" (e.g. galaxies) aren't shrinking. So this is moot. You are "talking to a wall" because your idea is not equivalent to what we observe, nor the model we have to explain what we observe. Galaxies are getting further apart, but they are not changing size.

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That is a good point. Galaxies are not expanding and so, under the suggested coordinate transform, they would not be shrinking. What would be shrinking is the units we measure distance in. But again, only on a large scale (because expansion only occurs on the large scale).

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On 5/14/2014 at 9:12 PM, michel123456 said:

Scaling does happen, we are scaled continuously, and because we are looking constantly into the past, what we are observing in the past has another scaling factor than the one we have today.

this is what i meant. 

On 5/15/2014 at 8:29 PM, Strange said:

What would be shrinking is the units we measure distance in. But again, only on a large scale (because expansion only occurs on the large scale).

@ shrinking is the units we measure distance in + @expansion only occurs on the large scale

said units are not shrinking, its the effect of time on large scale

 

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On 5/14/2014 at 9:12 PM, michel123456 said:

 

What I could swallow is the following:

Scaling does happen, we are scaled continuously, and because we are looking constantly into the past, what we are observing in the past has another scaling factor than the one we have today.

That would make sense.

it does resonate (to me)

On 5/15/2014 at 8:29 PM, Strange said:

What would be shrinking is the units we measure distance in

or, this would appear so only becaouse precisely of "building up of time"

this also resonates, but havent taken any effort to elaborate, the part that she is talking about "zooming in and getting thep recise same 'object' over and over again'. This is the "thing" on the micro level imho. will have to sit down and elaborate, maybe in next 5 years :)

 

 

 

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29 minutes ago, wucko said:

or, this would appear so only becaouse precisely of "building up of time"

Please define exactly what "building up of time" means. Also please provide some evidence that (a) this happens and (b) that it causes the observed effects.

Please show your calculations.

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On 5/15/2014 at 6:26 PM, michel123456 said:

The same exact effect is obtained when you keep the grid as it is, and shrink the points.

Don’t forget though that GR as a model does not stand in isolation - the large-scale physics of the universe need to remain compatible with the small-scale physics of the Standard Model. Unfortunately the QFD and QCD parts of the Standard Model Lagrangian are not scale invariant, so you cannot replace a universal expansion with a contracting observer, without breaking some crucial physics in the process.

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On 5/20/2012 at 5:23 PM, mindless said:

 

Time is a hugely complex subject. The Time of Relativity theory is undoubtedly akin to a negative spacial dimension (cf Weyl's analysis), recent experiments on quantum interference through time reinforce this view (see Lindner et al 2005). The time of Change is highly correlated with the dimensional time of Relativity but may not be exactly the same, for instance according to Multiverse theories two differing outcomes may coexist and be derived at the same location in a common spacetime. The time of causation is also problematical, as Reichenbach pointed out, the spherical symmetry of spacetime means that although chains of cause and effect can be pursued into the future it is difficult to pursue them into the past - for instance try to calculate the inverse of a spreading ripple from a needle dipped into a pond so that the disturbance at the edge of the pond ends up as a dip in the water surface at the exact place that the needle entered. Even more complex, try to think of something that exists for no time at all. Can an object have no temporal parts?

 

Lindner, F., Schaetzel, F.G., Walther, H., Baltuska, A., Goulielmakis, E., Krausz, F., Milosevic, D.B., Bauer, D., Becker, W., and Paulus, G.G.. (2005) Attosecond double-slit experiment. Phys.Rev.Lett. 95,040401 (2005)

That. Bolded by me. To be used in another thread.

Edited by michel123456

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