Vitruvian metric expansion of space

[michel123456]

After discussing a lot in another thread, I wanted to post my POV about the metric expansion of space.

Here below a sketch of what I think is happening: in short, when the metric of space is doubled, time doesn't change.

 

Here we are:

 

 

Leonardo's vitruvian man on the right is double in scale relative to the left one.

 

If both are observers, they observe light travelling at constant velocity C, each one in their own metric.

 

Both are observing the same thing, there is no absolute reference that says the left man is correct while the other is wrong. Both must be correct.

So light is travelling at the same apparent velocity as observed locally by each one of them.

And the result is shown here: while space is scaled, time is not. The dot arrives at the same time in the 2 images.

Edited October 25, 2012 by michel123456

[md65536]

If both are observers, they observe light travelling at constant velocity C, each one in their own metric.

If c remains constant relative to their own metric, or local ruler, then the ruler is expanding at the same rate as space?

 

What is the meaning of expansion if the ruler also expands? The size of the universe relative to the length of the ruler doesn't change. How do you measure expansion, if your measurement is the same before and after the expansion?

 

 

[michel123456]

If c remains constant relative to their own metric, or local ruler, then the ruler is expanding at the same rate as space?

Yes, that's the metric expansion.

 

What is the meaning of expansion if the ruler also expands? The size of the universe relative to the length of the ruler doesn't change.

Yes, exactly. "If all distances in the universe were doubled over night, nothing would tell us this had happened." (Julian Barbour-shape dynamics)

 

How do you measure expansion, if your measurement is the same before and after the expansion?

You can if you have the ability to observe now the difference in expansion in the past.

Edited October 26, 2012 by michel123456

[md65536]

Yes, exactly. "If all distances in the universe were doubled over night, nothing would tell us this had happened." (Julian Barbour-shape dynamics)

 

You can if you have the ability to observe now the difference in expansion in the past.

Do you agree that nothing would tell us this had happened, or do you think we'd have the ability to observe the difference?

[michel123456]

Do you agree that nothing would tell us this had happened, or do you think we'd have the ability to observe the difference?

 

We cannot observe the way we were yesterday to conclude that we changed metric in one night. Because our own past is not directly observable.

But since we can see the past all around us, we should be able to discern something .

 

J.Barbour's quote supposes that "all distances in the universe" changed at once (over night). But even if it was possible, we are unable to observe that happening at once: we observe everything with a gap in time. The farthest, the oldest.

Edited October 26, 2012 by michel123456

[michel123456]

Here below 3 diagrams representing the same scaling at 3 different rates.

 

 

 

Edited November 3, 2012 by michel123456

[md65536]

If it's possible to detect that this has happened, does that mean that we'd be able to tell that lengths (or rulers) in the past were smaller than they are now, and also that the speed of light in the past was c when measured using local (in the past) rulers? So then the speed of light in the past, if measured using one of our current rulers, would be less than c?

 

What observations or evidence would support this?

 

Is this meant to explain inflation as well? Does this imply that if a light signal is measured to be 13 billion years old, it is from an object that was 13 B light-years away, and that "expanded" 13 B light-years was always 13 B light-years (though according to smaller rulers in the past)?

[Spyman]

... we should be able to discern something .

Handwaving.

[michel123456]

... we should be able to discern something .

Handwaving.

 

...some kind of mysterious inertia.

A force oriented from outside to the inside.

[Spyman]

...some kind of mysterious inertia.

A force oriented from outside to the inside.

Indulging excessively in exercise that strain your arms can lead to severe pain.

[michel123456]

this post to lock your previous answer.

[md65536]

Well it sounds to me like an alternative to cosmic expansion that "makes more sense to you", but unfortunately doesn't seem to explain any of the observations that we're seeing. Eg. how does redshifting fit in? How does the Big Bang fit in, or what is the alternative? It seems to me, expansion and inflation that are not like you describe here, would still be needed to explain those things. Then, what does this idea explain or improve on where the existing theories are deficient?

[JohnStu]

So thus space-time expansion is irrelevant to all events?

 

 

 

That's what I have written down in fact in my upcoming e-book on the iBookStore

[michel123456]

Well it sounds to me like an alternative to cosmic expansion that "makes more sense to you", but unfortunately doesn't seem to explain any of the observations that we're seeing. Eg. how does redshifting fit in? How does the Big Bang fit in, or what is the alternative? It seems to me, expansion and inflation that are not like you describe here, would still be needed to explain those things. Then, what does this idea explain or improve on where the existing theories are deficient?

 

Well, the main point on which IMHO the existing theory is deficient lies on the fact that the existing model supposes that something that we don't know anything about its structure (space), something that has been proved is not existing (aether), something that is not under the limitations of Relativity (expanding space), that this "something" is the source of our observations (redshift). To me it is a huge deficiency.

It looks to me much more logical to presume that something else happening into tangible things is the source of our observations.

 

_about redshift, have a look at this attempt to show the equivalence of redshift with scaling in my other thread. as it seems, it is established science not even speculation, please tell me if I am wrong.

 

_yes expansion (or contraction) is needed. The difference is that the process happens inside material objects, and not between them.

 

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

(edit)

_The scaling factor could also explain why we get this blurry image of things when we look into the extremally small.

_It is also an answer to the question that worries J. Barbour, about Relativity of size. See here under "Shape Dynamics"

 

Shape DynamicsIn the last few years, Niall Ó Murchadha, several students, and I have explored the implications of the relativity of size (current research). If all distances in the universe were doubled over night, nothing would tell us this had happened. We therefore believe that relativity of size should be built into the foundations of dynamics. Strangely, Einstein’s general relativity just fails to implement perfect relativity of size. This is what allows the universe to expand in his theory. The Big Bang violates relativity of size. Most cosmologists accept this without even realising that it is an issue. We created a scale-invariant theory very like general relativity but with perfect relativity of size. However, our construction was not satisfactory, being unable to explain fundamental observational facts in cosmology. Relativity of size is such an attractive principle, I long believed that a dynamics of pure shape would one day be found, but in the last two years my thinking has changed somewhat. The changed perspective is reflected in the final four papers in Papers before the two on maximal variety. These define a theory of gravity that my current collaborators and I call Shape Dynamics. It retains the essential dynamical core of general relativity while removing in a well-motivated way structure that is potentially redundant and may well be responsible for the difficulties in the creation of quantum gravity. My collaborators Henrique Gomes, Sean Gryb, Tim Koslowski and Flavio Mercati are now working actively on Shape Dynamics and have obtained very interesting and encouraging results, the first of which are already published in two of the four papers just mentioned.(...)

 

So, if I follow correctly, the BB shouldn't fit. I deeply apologize for that.

 

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

(edit#2)

But

_it could be an explanation for the irreversibilty of time.

-it could be an explanation to the equivalence of gravity with acceleration if one notices that scaling has an inherent link to acceleration. See this wonderful post #16 from dear friend IGGY in this thread and my comment post #20.

Edited November 6, 2012 by michel123456

[Spyman]

Well, the main point on which IMHO the existing theory is deficient lies on the fact that the existing model supposes that something that we don't know anything about its structure (space), something that has been proved is not existing (aether), something that is not under the limitations of Relativity (expanding space), that this "something" is the source of our observations (redshift). To me it is a huge deficiency.

Claims that the theory of relativity which is now considered to be a cornerstone of physics is to be equal to "not know anything" about space structure is clearly ridiculous, there is no "aether" involved in accepted modern cosmology as the term is usually considered to be used and expanding space is a consequence of relativity even when the rate is not limited by the speed of light.

 

The simple truth is that your "Vitruvian metric expansion of space and time" is disproved by current observations of the Universe around us.

 

From your own quote:

"We created a scale-invariant theory very like general relativity but with perfect relativity of size. However, our construction was not satisfactory, being unable to explain fundamental observational facts in cosmology."

(Bolding by me.)

 

Current observations and knowledge overwhelmingly support models that rely on space expanding through a change in metric.

 

Link to Observational evidence

 

The Big Bang theory is the current prevailing cosmological model that describes the development of the Universe for a reason.

(And I don't apologize for that, it is not my fault.)

[michel123456]

Amen

[michel123456]

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

Anyway

 

That was not the intention of the OP. You can erase the vitruvian man and keep the dot alone if you want, that would show roughly what an expanding metric means.

The intention was to show that no matter the scaling factor, no matter the rate at which the scaling factor happens, the dot travels the same metric in the same time. See post #1

[md65536]

something that has been proved is not existing (aether),

 

Aether hasn't been proven to not exist; it's been proven to not be necessary.

 

My take on your theory is that it is meant as a simpler explanation for something that mainstream science already explains. Unfortunately, your theory doesn't explain anything. Like aether, it is unnecessary. Also like aether, there is no evidence for it. If it doesn't provide an alternative explanation for any of what mainstream science has, then it can't replace any of mainstream science, and if it adds nothing useful and new, then it is irrelevant.

 

I've tried to imagine how what you propose could explain observed redshifts, or what it means for predictions of the early universe, and I can't draw any concrete conclusions about it. That's where you can step in and defend your theory. What effects would be detectable if your theory is correct, and what predictions are a consequence of it, and how well do those predictions match observed evidence? It's just a forum so I don't think it has to be rigorous and exhaustive, but I think something at least specific is expected.

 

_The scaling factor could also explain why we get this blurry image of things when we look into the extremally small.

_It is also an answer to the question that worries J. Barbour, about Relativity of size. See here under "Shape Dynamics"

[...]

_it could be an explanation for the irreversibilty of time.

-it could be an explanation to the equivalence of gravity with acceleration if one notices that scaling has an inherent link to acceleration. See this wonderful post #16 from dear friend IGGY in this thread and my comment post #20.

Yes, it could explain everything, just like half of the theories in Speculations can. But does it? Vague descriptions of connections between things fall under what is known as hand waving.

 

 

[michel123456]

Aether hasn't been proven to not exist; it's been proven to not be necessary.

 

My take on your theory is that it is meant as a simpler explanation for something that mainstream science already explains. Unfortunately, your theory doesn't explain anything. Like aether, it is unnecessary. Also like aether, there is no evidence for it. If it doesn't provide an alternative explanation for any of what mainstream science has, then it can't replace any of mainstream science, and if it adds nothing useful and new, then it is irrelevant.

 

I've tried to imagine how what you propose could explain observed redshifts, or what it means for predictions of the early universe, and I can't draw any concrete conclusions about it. That's where you can step in and defend your theory. What effects would be detectable if your theory is correct, and what predictions are a consequence of it, and how well do those predictions match observed evidence? It's just a forum so I don't think it has to be rigorous and exhaustive, but I think something at least specific is expected.

 

 

Yes, it could explain everything, just like half of the theories in Speculations can. But does it? Vague descriptions of connections between things fall under what is known as hand waving.

(bolded mine)

The first effect is gravity. It links the equivalence principle to the fact that scaling is a form of acceleration. It also explains why gravity corresponds to a vector oriented from the outside to the inside.

 

The second effect is irreversibility. How could you go back in time when your own metric has changed ?

 

Third, the scaling factor is not something new, it is part of conventional knowledge. The only thing I want to humbly introduce is the concept of scaling happening inside material objects and not very far away between galaxy clusters.

 

And yes, waving hands is painful.

Edited November 8, 2012 by michel123456

[md65536]

The first effect is gravity. It links the equivalence principle to the fact that scaling is a form of acceleration. It also explains why gravity corresponds to a vector oriented from the outside to the inside.

 

The second effect is irreversibility. How could you go back in time when your own metric has changed ?

 

Third, the scaling factor is not something new, it is part of conventional knowledge. The only thing I want to humbly introduce is the concept of scaling happening inside material objects and not very far away between galaxy clusters.

Well okay, this is a start.

 

3rd: I think that expansion is already predicted to happen across all distances??? It's just that for smaller distances, gravity and other forces overwhelm the expansion, overriding its effects. Very distant objects have more space between them, and the more space the greater the effect of its expansion.

 

2nd: How do you know that Vitruvian metric expansion is not time-reversible? For example I could say "Throwing a ball explains the arrow of time, because if you reversed time, the ball would keep going forward," mistakenly assuming that motion is not time-reversible just because time itself seems irreversible.

 

1st: In your diagrams, everything is expanding at a fixed ratio. If gravity is equivalent to the expansion, wouldn't this imply that gravitational force would be a function of distance, but not of mass?

 

 

I'm not saying the idea has no value, just that the value is in the details. It may be possible to develop the idea until it fits.

[michel123456]

Well okay, this is a start.

 

3rd: I think that expansion is already predicted to happen across all distances??? It's just that for smaller distances, gravity and other forces overwhelm the expansion, overriding its effects. Very distant objects have more space between them, and the more space the greater the effect of its expansion.

 

2nd: How do you know that Vitruvian metric expansion is not time-reversible? For example I could say "Throwing a ball explains the arrow of time, because if you reversed time, the ball would keep going forward," mistakenly assuming that motion is not time-reversible just because time itself seems irreversible.

 

1st: In your diagrams, everything is expanding at a fixed ratio. If gravity is equivalent to the expansion, wouldn't this imply that gravitational force would be a function of distance, but not of mass?

 

I'm not saying the idea has no value, just that the value is in the details. It may be possible to develop the idea until it fits.

(bolded mine)

 

Thank you md65536 for participating.

 

What is very interesting in your remarks is about distance: indeed gravitational force is a function of distance*. But what distance? (remember that the metric is expanding) The goal would be to prove that as observed by the expanded observer, the gravitational force is a function of distance squared.

 

*and not only.

[md65536]

What is very interesting in your remarks is about distance: indeed gravitational force is a function of distance*. But what distance?

Indeed. And what direction does it predict that gravitational forces should point? It suggests that an expansion is somehow centered on each quantum of mass. This is not what the original idea proposes (a single universal uniform expansion).

 

This goes back to the original problem I see with this. On one hand it predicts nothing -- as you've mentioned if everything expanded while maintaining a constant ratio between any given lengths, there would be no way to know that it happened. And on the other hand it predicts everything (gravity, arrow of time, observations of distant galaxies, all the things you mentioned), which is a contradiction. I still see no concrete predictions (and I haven't imagined any), and with hand waving one could predict one thing as easily as the exact opposite thing.

 

Explaining "more stuff" without any details will only add problems. For example, if gravity is equivalent to cosmic expansion, why would we not see a stronger correlation between expansion and gravitation?

 

If the goal is to find something involving a square of distances, you might end up shoe-horning the idea to force it to fit what you want it to fit. I think a better goal would be to analyse: What are the consequences of the idea? If it happened, what might we see? Then if that doesn't fit what you want, modify the idea and iterate with more analysis, until it fits something or becomes unworkable.

 

As an example of where to start, imagine an observation of some distant object while this expansion is taking place. How is the observation different than if the expansion didn't take place? If there's no difference, is there some other measurement with a difference?

 

 

[michel123456]

Indeed. And what direction does it predict that gravitational forces should point? It suggests that an expansion is somehow centered on each quantum of mass. This is not what the original idea proposes (a single universal uniform expansion).

This goes back to the original problem I see with this. On one hand it predicts nothing -- as you've mentioned if everything expanded while maintaining a constant ratio between any given lengths, there would be no way to know that it happened. And on the other hand it predicts everything (gravity, arrow of time, observations of distant galaxies, all the things you mentioned), which is a contradiction. I still see no concrete predictions (and I haven't imagined any), and with hand waving one could predict one thing as easily as the exact opposite thing.

 

Explaining "more stuff" without any details will only add problems. For example, if gravity is equivalent to cosmic expansion, why would we not see a stronger correlation between expansion and gravitation?

 

If the goal is to find something involving a square of distances, you might end up shoe-horning the idea to force it to fit what you want it to fit. I think a better goal would be to analyse: What are the consequences of the idea? If it happened, what might we see? Then if that doesn't fit what you want, modify the idea and iterate with more analysis, until it fits something or becomes unworkable.

 

As an example of where to start, imagine an observation of some distant object while this expansion is taking place. How is the observation different than if the expansion didn't take place? If there's no difference, is there some other measurement with a difference?

 

It is what the original idea proposes, but it is very difficult to make a representation of it. If you try under euclidian geometry(as I did) you will see things crashing into each other. It works only under "expanding geometry".

 

___________-

(edit)

"expanded geometry" I suppose must exist already. It is the geometry of the raisin cake analogy, an expanding geometry without a centre.

Edited November 9, 2012 by michel123456

[md65536]

"expanded geometry" I suppose must exist already. It is the geometry of the raisin cake analogy, an expanding geometry without a centre.

But what does that have to do with gravity? Why is there a gravitational force toward mass, instead of "toward everywhere", if everywhere is expanding uniformly?

[michel123456]

But what does that have to do with gravity? Why is there a gravitational force toward mass, instead of "toward everywhere", if everywhere is expanding uniformly?

 

If you mean by "toward everywhere" the same as "the centre is everywhere", yes, it is the way it goes.