# The speed of time

## Recommended Posts

35 minutes ago, AbstractDreamer said:

the FLRW metric to describe a Universe that changes over time - it "looks different at different moments in time".  Is this not in contradiction with its OWN premise of homogeneity of the Universe?

So, since the metric is a function of time, then time itself has to be a function of time ???

• Replies 86
• Created

#### Popular Days

If there isn't any measurable effect, then time changing doesn't matter - there is no effect. I will borrow and analogy I've read elsewhere: if you propose that there is a massless invisible gorilla in the room, and there are no gorilla effects that can be detected, then your proposition is not a scientific one. It's meaningless.

What people investigate is whether dimensionless constants change over time, such as the fine structure constant. And the limit on how much that might have changed is quite small (a part in 10^17 per year as an upper bound)

##### Share on other sites

On 9/15/2022 at 4:42 PM, swansont said:

If there isn't any measurable effect, then time changing doesn't matter - there is no effect. I will borrow and analogy I've read elsewhere: if you propose that there is a massless invisible gorilla in the room, and there are no gorilla effects that can be detected, then your proposition is not a scientific one. It's meaningless.

What people investigate is whether dimensionless constants change over time, such as the fine structure constant. And the limit on how much that might have changed is quite small (a part in 10^17 per year as an upper bound)

What if the effect is not measurable, but observable, such as the receeding of galaxies very far ago?

What if I propose a massless invisible gorilla in the room that cannot be measured, but I point at the banana peels on the floor as an observation?

On 9/15/2022 at 3:33 PM, MigL said:

So, since the metric is a function of time, then time itself has to be a function of time ???

As far as understand the metric assumes a time over time is flat with uniform axis, and that it is space over time that is allowed to have axes that stretch.  Why one and not the other?

red, but I point at the banana peels on the floor as an observation?

On 9/15/2022 at 3:33 PM, MigL said:

So, since the metric is a function of time, then time itself has to be a function of time ???

As far as understand the metric assumes a time over time is flat with uniform axis, and that it is space over time that is allowed to have axes that stretch.  Why one and not the other?

So we notice that the wavelength of photons are redshifted cosmologically, and for far ago galaxies they are receeding faster than the speed of light, and we say that is possible as the space between us is expanding.

Nothing wrong with this logic at all, but there is no basis other than "it seems obvious" to allow space to expand to explain the red shift - and that FLRW metric expansion of space has been arbitrarily tuned to agree with observations.   But what is wrong with this interpretation:

So we notice that the wavelength of photons are redshifted cosmologically, and for far ago galaxies they are receeding faster than the speed of light, and its possible that time between us is contracting.

So the cosmological redshift might not be not further away in distance due to space expansion, but further away in time due to time contraction.  A metric contraction of time.

##### Share on other sites

1 hour ago, AbstractDreamer said:

What if the effect is not measurable, but observable, such as the receeding of galaxies very far ago?

In what way is the receding of galaxies not measurable?

I can't think of anything that is observable that is not measurable in some way.

1 hour ago, AbstractDreamer said:

What if I propose a massless invisible gorilla in the room that cannot be measured, but I point at the banana peels on the floor as an observation?

That would be an indirect measurement of them, so it would not fulfill the notion that there is no interaction. The interaction is that they eat bananas and render them invisible, and leave the peels behind.

This is how neutrinos were theorized, and then detected. It's perfectly fine to do so. What you need to do is find some effect that the non-constant time would have. What is the variable time equivalent of the banana in that scenario?

2 hours ago, AbstractDreamer said:

So the cosmological redshift might not be not further away in distance due to space expansion, but further away in time due to time contraction.  A metric contraction of time.

Is this consistent with all distance measurements, like supernovae, cepheids, parallax, etc.?

##### Share on other sites

3 hours ago, swansont said:

In what way is the receding of galaxies not measurable?

I can't think of anything that is observable that is not measurable in some way.

Sorry, I was imprecise.  The receding of the galaxies is not a measurable it is the conclusion.  All we have are measurements of spectral emission lines from type 1a supernovae which indicate non-linear distance-redshift relationship at very large distances.

Afaik, that there is no other measurable (besides cosmological redshift) that is explained by space expansion.   And space expansion is not directly measureable or testable at shorter distances.   Going out on a limb, how can we ever directly test for space expansion, without an experiment that spans a distance where such expansion might be evident?

3 hours ago, swansont said:

The interaction is that they eat bananas and render them invisible, and leave the peels behind.

We all agree there are peels on the floor.  But instead of massless invisible gorillas, we decide that "self-arranging atoms" decide to spontaneously form banana peels directly from thick air makes more sense.   For this analogy, the peels are the red-shifted measurements; time contraction is the ludicrous massless invisible gorillas theory; and space expansion is the spontaneous banana-forming self-organising atoms theory.  From my perspective both are viable, but why do we choose one and reject the other?

3 hours ago, swansont said:

What you need to do is find some effect that the non-constant time would have. What is the variable time equivalent of the banana in that scenario?

Space expansion is such an effect - or more precisely cosmological redshift.   Space does not need to expand to cause redshift.  If time contracts, we can achieve the same result.  The experience of contracted time for the photon is "baked" into the wavefunction of the photon during the experience, which results in two perspectives: either a lengthening of the  wavelength as measured by an observer "trapped" in the same time as the photon (me and you and most everything else in the universe trapped in time); or an unstretched wavelength as measured by an observer "outside" the influence of time (neither me or you or most things in the universe)

3 hours ago, swansont said:

Is this consistent with all distance measurements, like supernovae, cepheids, parallax, etc.?

In the same way the FLRW metric is tuned to BE consistent with such measurements, there might be solutions to metric of time contractions that are equally consistent.  Perhaps preserving the uniform axes of space, but not necessarily so for other solutions.  The counter argument where we could wildly choose functions of time is absurd; of course it would have to fit cosmological red shift measurements.  Just like wildly choosing solutions to the field equations does not mean fitting solutions like the FLRW metric cant be found.

Edited by AbstractDreamer
##### Share on other sites

2 hours ago, AbstractDreamer said:

All we have are measurements of spectral emission lines from type 1a supernovae which indicate non-linear distance-redshift relationship at very large distances.

That is imprecise and incorrect.  It would seem to me that you should have a good understanding of a theory before you dismiss it.

##### Share on other sites

5 hours ago, AbstractDreamer said:

Sorry, I was imprecise.  The receding of the galaxies is not a measurable it is the conclusion.  All we have are measurements of spectral emission lines from type 1a supernovae which indicate non-linear distance-redshift relationship at very large distances.

Afaik, that there is no other measurable (besides cosmological redshift) that is explained by space expansion.   And space expansion is not directly measureable or testable at shorter distances.   Going out on a limb, how can we ever directly test for space expansion, without an experiment that spans a distance where such expansion might be evident?

If direct tests were required of physics there would not be much physics going on. So that’s an artificial requirement.

5 hours ago, AbstractDreamer said:

We all agree there are peels on the floor.

Not in my example.

In yours, fine. Then you have indirect evidence.

5 hours ago, AbstractDreamer said:

But instead of massless invisible gorillas, we decide that "self-arranging atoms" decide to spontaneously form banana peels directly from thick air makes more sense.

You would need a compelling model, and evidence to support it, that explains why this makes more sense.

##### Share on other sites

4 hours ago, Bufofrog said:

That is imprecise and incorrect.  It would seem to me that you should have a good understanding of a theory before you dismiss it.

Feel free to be helpful and explain where I'm wrong.

1 hour ago, swansont said:

You would need a compelling model, and evidence to support it, that explains why this makes more sense.

The evidence is cosmological redshift.  Can you explain why space expansion is a compelling model and makes more sense?

##### Share on other sites

1 hour ago, AbstractDreamer said:

Feel free to be helpful and explain where I'm wrong.

You said, "All we have are measurements of spectral emission lines from type 1a supernovae".  The spectral emission lines are from the galaxy not the supernova.  The type 1a supernova have the same absolute magnitude.  By comparing the apparent magnitude to the absolute magnitude you can calculate the distance to the galaxy.  So therefore you can then relate the redshift (recession speed) of the galaxy to the distance of the galaxy calculated from the supernova.

##### Share on other sites

9 hours ago, AbstractDreamer said:

The evidence is cosmological redshift.  Can you explain why space expansion is a compelling model and makes more sense?

I was referring to your analogy, and claim that that '"self-arranging atoms" decide to spontaneously form banana peels directly from thick air makes more sense'

(you can tell I was referring to this because it's what I quoted with my response)

You offer this and them make a ludicrous claim about banana peels forming spontaneously as if this is a reasonable analogy.

As far as expansion goes, it's what is predicted by a wildly successful theory called General Relativity, and what agrees with the evidence, such as the redshift and the microwave background radiation, and the confirmation that the universe is, to a large degree, isotropic and homogeneous

##### Share on other sites

12 hours ago, Bufofrog said:

You said, "All we have are measurements of spectral emission lines from type 1a supernovae".  The spectral emission lines are from the galaxy not the supernova.  The type 1a supernova have the same absolute magnitude.  By comparing the apparent magnitude to the absolute magnitude you can calculate the distance to the galaxy.  So therefore you can then relate the redshift (recession speed) of the galaxy to the distance of the galaxy calculated from the supernova.

So its still redshift measurements is all we have as evidence for space expansion?

4 hours ago, swansont said:

I was referring to your analogy, and claim that that '"self-arranging atoms" decide to spontaneously form banana peels directly from thick air makes more sense'

(you can tell I was referring to this because it's what I quoted with my response)

You offer this and them make a ludicrous claim about banana peels forming spontaneously as if this is a reasonable analogy.

The analogy was to show that space expansion as a theory for explaining cosmological redshift is no more sensible or no less ludicrous, to me, as time contraction; that massless invisible gorillas are as ludicrous/sensible as self arranging atoms.  The analogy goes no further than that.  It is a perfectly reasonable analogy for this purpose.

Hence why I consequently asked what makes space expansion compelling and make more sense.

4 hours ago, swansont said:

As far as expansion goes, it's what is predicted by a wildly successful theory called General Relativity, and what agrees with the evidence, such as the redshift and the microwave background radiation, and the confirmation that the universe is, to a large degree, isotropic and homogeneous

I disagree that space expansion is predicted by GR.  GR predicts a static universe cannot be stable.  It is cosmological redshift observations that are interpreted as galaxies are moving away from us over distance that we then conclude  the universe is (currently) in a state of spatial expansion; and that is then used by GR, with tuning, to model its history to explain such expansion.

I am proposing a time contraction interpretation of cosmological redshift, where galaxies are not necessarily ONLY moving away from us spatially, but also temporally.    This interpretation can similarly agree with the evidence, such as redshift, MBR and that the universe is to a large degree isotropic and homogeneous, with the right metric and right tuning.

Essentially what this boils down to is why we prefer that the spatial metric is variable and that the metric of time is linear; and why we reject a linear spatial metric and a variable temporal metric.

The answer "because it fits" simply does not apply, because the alternative also fits

Edited by AbstractDreamer
##### Share on other sites

56 minutes ago, AbstractDreamer said:

I disagree that space expansion is predicted by GR.  GR predicts a static universe cannot be stable.

One has to look at the evidence, though. What would a contracting universe look like? (as we've ruled out a stable one)

56 minutes ago, AbstractDreamer said:

It is cosmological redshift observations that are interpreted as galaxies are moving away from us over distance that we then conclude  the universe is (currently) in a state of spatial expansion; and that is then used by GR, with tuning, to model its history to explain such expansion.

I am proposing a time contraction interpretation of cosmological redshift, where galaxies are not necessarily ONLY moving away from us spatially, but also temporally.    This interpretation can similarly agree with the evidence, such as redshift, MBR and that the universe is to a large degree isotropic and homogeneous, with the right metric and right tuning.

A problem here is the claim that the interpretation can agree with the evidence, but you have not provided an actual model to test. That's incredibly thin.

56 minutes ago, AbstractDreamer said:

Essentially what this boils down to is why we prefer that the spatial metric is variable and that the metric of time is linear; and why we reject a linear spatial metric and a variable temporal metric.

The answer "because it fits" simply does not apply, because the alternative also fits

You have to show that the alternative fits. One cannot say it does based on waving of hands, it requires a quantitative analysis to be able to say it fits. You would not just be getting rid of some parts of GR with your conjecture. How does your idea affect the fine structure constant, for example?

And just how much of GR are you dispensing with? GR makes predictions other than expansion.

##### Share on other sites

On 9/12/2022 at 8:18 AM, AbstractDreamer said:

I don't think you could tell experimentally.  But my question is really: If we assume that time is constant over time, WHY do we assume that?  What evidence is there?  I'm guessing there is no evidence, hence my questions here.  As physics is based on evidence, why is this one assumption exempt?  What are the theories in the scientific community that considers time over time as non constant?

This is the nature of 4-D spacetime conjunction, as I understand it: it morphed out from the start and it's the same t=0->t=$\infty$. Yes there are other theories questioning time, although I dont know exactly if it's such that "time over tme as non constant" is the consideration; I sent a PM.

On 9/12/2022 at 8:18 AM, AbstractDreamer said:

I'll posit again that motion or potential changing the experience of time is missing the point.   In a thought experiment, take two volumes of spacetime, both identical in motion and gravitation potential, and identical all other properties EXCEPT in the property of time.  One volume is close to t=0, and the other volume is close to t=infinity.

Theoretically or mathematically, but not experimentally, comparing the progress of time in each volume relative to the other volume, why do we assume they are the same?

This is, I think,the adaptaton of the equivalence principle as swansont referred to it: it is taken as proved that we can apply the Lorentz transformations to compare these events at different time points t=0 and t=$\infty$ and they will be invariant if done properly. From Relativity, short-bus version, pg. 148, Appendix V,

Quote

The answer to this question is the special theory of relativity. This takes over from the theory of Maxwell-Lorentz the assumption of the constancy of the velocity of light in empty space [ed.:what do you suppose that entails about time in this theory?]. in order to bring this into harmony with the equivalence of inertial systems (special principle of relativity), the idea of the absolute character of simultaneity must be given up; in addition, the Lorentz transformations for the tme and the space co-ordinates follow for the transition from one inertial system to another. The whole content of the special theory of relativity is included in the postulate: The laws of Nature are invariant with respect to the Lorentz transformations [ed. occurences/laws at t=0 equatable to t=$\infty$]. The important thing of this requirement lies in the fact that it limits the possible natural laws in a definite manner.

On 9/12/2022 at 10:04 AM, swansont said:

There’s no evidence that it’s not, for any clock relative to another clock in the same frame of reference. People have looked for deviations from the predictions of relativity and haven’t found any.

Null result for aether? Or does Dayton Miller's interferometer experiment point at anisotropy of light and undercut SR and GR? Unverified A.E. quotes:

Quote

"My opinion about Miller's experiments is the following. ... Should the positive result be confirmed, then the special theory of relativity and with it the general theory of relativity, in its current form, would be invalid. Experimentum summus judex. Only the equivalence of inertia and gravitation would remain, however, they would have to lead to a significantly different theory."
— Albert Einstein, in a letter to Edwin E. Slosson, July 1925

"I believe that I have really found the relationship between gravitation and electricity, assuming that the Miller experiments are based on a fundamental error. Otherwise, the whole relativity theory collapses like a house of cards."
— Albert Einstein, in a letter to Robert Millikan, June 1921 (in Clark 1971, p.328)

https://www.anti-relativity.com/daytonmiller.htm

On 9/12/2022 at 10:04 AM, swansont said:

AFAIK there are none. Certainly none with evidence to support them.

How would we not notice this? That there is a time rate difference other than what we know to account for? If frequencies differ from expected, it would show up., and violate Einstein’s equivalence principle.

Einstein’s equivalence principle

No, I don't think it would show up, precisely because we take our ticking clocks on Earth to be uniform and relatively undisturbed. Once that is solidified, we can do Fourier Transformations on data.

On 9/13/2022 at 7:30 AM, AbstractDreamer said:

If spacetime is a continuum, and space has been observed to expand, why is it not described as time contraction?  Why must the constancy and consistency of time be preserved?  What makes the immutability of time more sacred than space?

They are bound together in the spacetime paradigm, and I do think that time is presumed to be constant unless there is a relative acceleration that causes a dilation or contraction; similarly distances are contracted or dilated under a relative acceleration. my inference here I think is that it could go both ways assuming some deceleration; officially it may be length contractions and time dilations.

On 9/15/2022 at 6:56 AM, AbstractDreamer said:

Its made up in the same way that we assume time is constant over time.   Any observations or experimental evidence that is itself "trapped" in time can neither support or disprove either that time is constant or non-constant.     And yet we are happy, without evidence or measurement, to assume it is constant; and draw as a useful conclusion, the FLRW metric to describe a Universe that changes over time - it "looks different at different moments in time".  Is this not in contradiction with its OWN premise of homogeneity of the Universe?

support or disprove either that time is constant or non-constant. To repeat myself, I think the definiton of time is that it is a repeating period, or interval, or what you called a Gap. Think of a metronome, or an oscillator like a penduluum: the repetitive period, the constancy, is what we use time for measuring other things against. To figure on whether the rate of passage of time in a reference frame could be dilated, we need another time measuring device to compare with.. so the thinking goes.

On 9/22/2022 at 10:54 AM, AbstractDreamer said:

Sorry, I was imprecise.  The receding of the galaxies is not a measurable it is the conclusion.  All we have are measurements of spectral emission lines from type 1a supernovae which indicate non-linear distance-redshift relationship at very large distances.

We really need that Fourier transform data to be valid.

On 9/22/2022 at 10:54 AM, AbstractDreamer said:

Afaik, that there is no other measurable (besides cosmological redshift) that is explained by space expansion.   And space expansion is not directly measureable or testable at shorter distances.   Going out on a limb, how can we ever directly test for space expansion, without an experiment that spans a distance where such expansion might be evident?

Yes, I think we would have to get two observation points, let's say one on Earth, and one at the midpoint between here and the apparent edge/end of the universe, in order to try to triangulate a non-local measurement to the boundary. Whether optical or other frequency range would be valid I don't know.

On 9/22/2022 at 10:54 AM, AbstractDreamer said:

We all agree there are peels on the floor.  But instead of massless invisible gorillas, we decide that "self-arranging atoms" decide to spontaneously form banana peels directly from thick air makes more sense.   For this analogy, the peels are the red-shifted measurements; time contraction is the ludicrous massless invisible gorillas theory; and space expansion is the spontaneous banana-forming self-organising atoms theory.  From my perspective both are viable, but why do we choose one and reject the other?

Space expansion is such an effect - or more precisely cosmological redshift.   Space does not need to expand to cause redshift.  If time contracts, we can achieve the same result.  The experience of contracted time for the photon is "baked" into the wavefunction of the photon during the experience, which results in two perspectives: either a lengthening of the  wavelength as measured by an observer "trapped" in the same time as the photon (me and you and most everything else in the universe trapped in time); or an unstretched wavelength as measured by an observer "outside" the influence of time (neither me or you or most things in the universe)

In the same way the FLRW metric is tuned to BE consistent with such measurements, there might be solutions to metric of time contractions that are equally consistent.  Perhaps preserving the uniform axes of space, but not necessarily so for other solutions.  The counter argument where we could wildly choose functions of time is absurd; of course it would have to fit cosmological red shift measurements.  Just like wildly choosing solutions to the field equations does not mean fitting solutions like the FLRW metric cant be found.

I don't have it in the multi-quote, but you allude to the difficulty of an observation frame outside time. I don't have the hardest time conceiving such a thing, it only requires you split space from time. Presuming conception of a 3-Dimensional space translating over the course of time we have a trace of the development of all worldlines, not in the proper relativity sense I don't think, but just a common sense idea. The aggregate over all time you could call eternity. So as a thought experiment I think it's easy, although I can't actually extricate myself from thinking in terms of causality here.

15 hours ago, Bufofrog said:

You said, "All we have are measurements of spectral emission lines from type 1a supernovae".  The spectral emission lines are from the galaxy not the supernova.  The type 1a supernova have the same absolute magnitude.  By comparing the apparent magnitude to the absolute magnitude you can calculate the distance to the galaxy.  So therefore you can then relate the redshift (recession speed) of the galaxy to the distance of the galaxy calculated from the supernova.

Hey Bufofrog,

Can we conclude that the spectral emissons are traveling uniformly through space? For the sake of the premise here, what if at some point in transit there was a time dilation effecting the frequency or perhaps amplitude of spectral data received on Earth?

Edited by NTuft
amplitude
##### Share on other sites

3 hours ago, AbstractDreamer said:

I am proposing a time contraction interpretation of cosmological redshift, where galaxies are not necessarily ONLY moving away from us spatially, but also temporally.

This runs into the same problem as "the universe is not expanding; everything in it is getting smaller".

The fact is, the universe is only expanding at certain scales; below those scales, galaxies may actually be coming together, such as our galaxy and Andromeda, because the gravitational coupling exceeds the 'dark energy' of the expansion.

IOW, expansion is distance ( scale ) dependent.

##### Share on other sites

3 hours ago, NTuft said:

Can we conclude that the spectral emissons are traveling uniformly through space?

I would think not since they red shifted for distant objects.

3 hours ago, NTuft said:

For the sake of the premise here, what if at some point in transit there was a time dilation effecting the frequency or perhaps amplitude of spectral data received on Earth?

I have no idea how that could happen, so it doesn't seem likely.

7 hours ago, AbstractDreamer said:

So its still redshift measurements is all we have as evidence for space expansion?

I believe that is correct.

##### Share on other sites

5 hours ago, NTuft said:

Null result for aether? Or does Dayton Miller's interferometer experiment point at anisotropy of light and undercut SR and GR?

You have to look at the weight of the evidence. The fact that a whole bunch of results show a null result and one does not points to some kind of experimental bias in the one experiment.

Quote

No, I don't think it would show up, precisely because we take our ticking clocks on Earth to be uniform and relatively undisturbed. Once that is solidified, we can do Fourier Transformations on data.

Are you suggesting we don’t routinely compare clocks with each other? I can assure you we do. For normal timekeeping, and also for tests of relativity

##### Share on other sites

On 9/23/2022 at 4:53 PM, swansont said:

One has to look at the evidence, though. What would a contracting universe look like? (as we've ruled out a stable one)

A problem here is the claim that the interpretation can agree with the evidence, but you have not provided an actual model to test. That's incredibly thin.

You have to show that the alternative fits. One cannot say it does based on waving of hands, it requires a quantitative analysis to be able to say it fits. You would not just be getting rid of some parts of GR with your conjecture. How does your idea affect the fine structure constant, for example?

And just how much of GR are you dispensing with? GR makes predictions other than expansion.

A universe like ours that experienced and experiences an adjustment of the metric of time instead of the metric of space in space expansion, could look exactly like how ours started and evolved to what it is today.

I'm not competent enough to provide an actual model, at least one that would satisfy actual physicists. I just have a obscure idea that I'm struggling to find words to describe, without every other response misunderstanding my meaning.  For analogy, its like I'm asking why glass is not half empty instead of half full, and some responses are because the water is half the volume of the glass.  The answer is missing the point.

I cannot show the alternative fits.  I'm asking why it cannot fit.   I'm not necessarily getting rid of any parts of GR.  I have no idea how it affects the fine structure constant.  How does space expansion affect the fine structure constant?  Is the fine structure constant different at two locations separated by a distance large enough to measure cosmological redshift?  I doubt we have any evidence of such measurement.

I'm not dispensing of anything within GR.  Whatever mathematics are used to describe space expansion, such as the scale factor of expansion, or the cosmological constant, I am re-interpreting what some of the variables actually represent, rather than the  equations themselves.

On 9/24/2022 at 12:57 AM, swansont said:

Are you suggesting we don’t routinely compare clocks with each other? I can assure you we do. For normal timekeeping, and also for tests of relativity

We have never compared at a single moment in time, a clock ticking at that moment, with it's historical ticking at the same moment (future moment relative to the historic clock).  Any measure of the clock historically has also been made at the historic time of measurement.  The time of measurement is trapped in time with the clock ticking.  So, while we routinely compare clocks, we are not exhaustively eliminating all possible variables in any of the comparisons, such as the potential variability of the metric of time.

On 9/23/2022 at 7:59 PM, MigL said:

The fact is, the universe is only expanding at certain scales; below those scales, galaxies may actually be coming together, such as our galaxy and Andromeda, because the gravitational coupling exceeds the 'dark energy' of the expansion.

IOW, expansion is distance ( scale ) dependent.

But this does not refute an idea of time metric contraction.  The whole point of this alternative perspective is to re-interpret cosmological redshift as a time metric contraction instead of space metric expansion.  Any/all characteristics, such as dependency, is automatically inherited.  That is, if expansion is distance dependent, so too is time metric contraction.

On 9/23/2022 at 7:40 PM, NTuft said:

They are bound together in the spacetime paradigm, and I do think that time is presumed to be constant unless there is a relative acceleration that causes a dilation or contraction; similarly distances are contracted or dilated under a relative acceleration. my inference here I think is that it could go both ways assuming some deceleration; officially it may be length contractions and time dilations.

Specifically, I want to distance this topic from time dilation due to motion and gravitational potential.   This time-metric-contraction idea is a separate entity and relates only to cosmological redshift observations.   In the same way that space expansion is a separate entity to curvature.

Edited by AbstractDreamer
clarity
##### Share on other sites

59 minutes ago, AbstractDreamer said:

A universe like ours that experienced and experiences an adjustment of the metric of time instead of the metric of space in space expansion, could look exactly like how ours started and evolved to what it is today.

I'm not competent enough to provide an actual model, at least one that would satisfy actual physicists.

A problem is that you can't make the claim of paragraph 1 if paragraph 2 is the case.

59 minutes ago, AbstractDreamer said:

I just have a obscure idea that I'm struggling to find words to describe, without every other response misunderstanding my meaning.  For analogy, its like I'm asking why glass is not half empty instead of half full, and some responses are because the water is half the volume of the glass.  The answer is missing the point.

I cannot show the alternative fits.  I'm asking why it cannot fit.   I'm not necessarily getting rid of any parts of GR.  I have no idea how it affects the fine structure constant.  How does space expansion affect the fine structure constant?  Is the fine structure constant different at two locations separated by a distance large enough to measure cosmological redshift?  I doubt we have any evidence of such measurement.

We have measured the fine structure constant. There is no effect from space expansion, because it's not dependent on space. But changing time? Does that affect the speed of light? One might imagine it does since the distance is the same but time is changing, but we don't know, because you don't have any science to point to that would give us a clue.

59 minutes ago, AbstractDreamer said:

I'm not dispensing of anything within GR.  Whatever mathematics are used to describe space expansion, such as the scale factor of expansion, or the cosmological constant, I am re-interpreting what some of the variables actually represent, rather than the  equations themselves.

Except you aren't because you have no math to present.

59 minutes ago, AbstractDreamer said:

But this does not refute an idea of time metric contraction.

It does, because expansion doesn't occur with gravitationally bound entities, and your proposal sounds like it would not; at least, there's nothing you've tied into it that would have such an effect. But your proposal doesn't come with enough detail to be sure.

If the idea isn't falsifiable it's not science.

##### Share on other sites

54 minutes ago, swansont said:

A problem is that you can't make the claim of paragraph 1 if paragraph 2 is the case.

I cant prove my claim, but I have asked you to falsify it and you haven't yet conclusively.  And it is not totally unreasonable like a massless invisible gorilla.  It relates directly to the spacetime continuum and why we allow the space-metric to stretch but not the time-metric.  It is a claim with sufficient reasoning to ask for a falsification before a complete proof is made.

55 minutes ago, swansont said:

If the idea isn't falsifiable it's not science.

In contrast, I have asked you show me evidence why we assume the metric of time is constant.  This idea is not falsifiable either, yet its science.   And you have not given me a sufficiently adequate answer yet.

On 9/23/2022 at 11:38 AM, swansont said:

As far as expansion goes, it's what is predicted by a wildly successful theory called General Relativity, and what agrees with the evidence, such as the redshift and the microwave background radiation, and the confirmation that the universe is, to a large degree, isotropic and homogeneous

This is the closest answer you have given me, which I have addressed previously as inappropriate for the question of specifically evidence for/against space metric expansion vs time metric contraction.  You need to give me another answer that proves space metric expansion AND NOT time metric contraction is the only viable and correct interpretation.

Either proof that my claim is refuted, or proof that the space-metric-expansion is the only correct interpretation of cosmological redshift.   If you can prove neither, then I would argue my claim has viability - without a full mathematical model.

54 minutes ago, swansont said:

Except you aren't because you have no math to present.

Can you show me the maths in the GR field equations for space-metric-expansion as starting point please?

54 minutes ago, swansont said:

We have measured the fine structure constant. There is no effect from space expansion, because it's not dependent on space. But changing time? Does that affect the speed of light? One might imagine it does since the distance is the same but time is changing, but we don't know, because you don't have any science to point to that would give us a clue.

If there is no effect from space expansion, and as the proposal of time-metric-contraction is an interpretation of space-metric-expansion, then it would inherit the same answer.  "There is no effect of time-metric-expansion on the fine structure constant".

I would argue one might imagine it does NOT affect speed of light as measured using any frames of reference that are trapped in the same time moment.

Edited by AbstractDreamer
##### Share on other sites

47 minutes ago, AbstractDreamer said:

If there is no effect from space expansion, and as the proposal of time-metric-contraction is an interpretation of space-metric-expansion, then it would inherit the same answer.  "There is no effect of time-metric-expansion on the fine structure constant".

Again, without a model, you can't guarantee this.

47 minutes ago, AbstractDreamer said:

I would argue one might imagine it does NOT affect speed of light as measured using any frames of reference that are trapped in the same time moment.

We know the speed of light is invariant - we have physics that tells us this. We see changes in light that occur with an invariant c and space expansion - a redshift that only occurs in regions that are not gravitationally bound. So if you want to propose that this is an effect on time you would need to explain why there is no time shift for gravitationally bound entities, where the redshift is not observed.

##### Share on other sites

14 hours ago, AbstractDreamer said:

I cannot show the alternative fits.  I'm asking why it cannot fit.

I don't think anyone said it cannot fit? Just that it is meaningless. In fact there are published papers that propose exactly what you're saying, they're just not accepted as mainstream science, mainly because they don't account for everything that the accepted science does. Accepted science is always changing (usually slowly) but it changes to better account for actual observations, not imagined alternatives (unless it's a useful improvement). A lack of evidence doesn't prove your alternative doesn't fit, just that it doesn't improve anything.

14 hours ago, AbstractDreamer said:

I'm not dispensing of anything within GR.  Whatever mathematics are used to describe space expansion, such as the scale factor of expansion, or the cosmological constant, I am re-interpreting what some of the variables actually represent, rather than the  equations themselves.

What it looks like to me, is that you're suggesting the possibility that instead of using GR to account for the universe as we observe it (where it fits very well for cosmology and large scales), we use it to account for something different than what we observe, and add in your proposals to account for the difference.

##### Share on other sites

20 hours ago, swansont said:

Again, without a model, you can't guarantee this.

I am using a principle of inheritance to say that without a model.   If you can demonstrate that you can drink a glass that is half full in one gulp, then the same glass that is half empty can also be drunk in one gulp without necessarily needing to demonstrate it - because the latter inherits all the properties of the former.   If a space expansion explanation of cosmological redshift does not affect the fine structure constant, then neither would a time-metric contraction explanation nor even a massless invisible gorilla explanation affect the fine structure constant.

20 hours ago, swansont said:

We know the speed of light is invariant - we have physics that tells us this. We see changes in light that occur with an invariant c and space expansion - a redshift that only occurs in regions that are not gravitationally bound. So if you want to propose that this is an effect on time you would need to explain why there is no time shift for gravitationally bound entities, where the redshift is not observed.

I beg for precision.  We know the speed of light is invariant with a constant metric of time.  We know the speed of light is invariant using any frame of reference at the same moment as the measurement of that speed.  These premises are fundamental and intrinsic to the physics of GR.  You cant use a theory to prove its own premises!

In the same way we cant explain why there is no (or insignificant) space expansion in volumes of curvature.  It's just an observable the redshift only occurs in "flatter" volumes.  Anything you can say about why space expansion is observed the way it is can be similarly attributed to any alternative explanation of redshift.

I have wildly speculated previously, the measuring of wavelengths are "trapped" in time with the waves themselves.   We literally cannot measure something yesterday or tomorrow.  We can measure something that was emitted yesterday and travelled a lightday through space to reach us.  But we can only measure it "right now".  If we did measure it yesterday,  it was measured "right then" and not "right now".   We cannot measure something "right now" as it was or will be at any other time than "right now".   The "fixing" of this time moment requires that the observer and the object be in the same moment.

But I propose that redshift is due to the continuum being stretched -  not just the space part.  It looks like the only the space part (wavelength stretching redshift) is changing because our observations are fixed in time with our objects.

9 hours ago, md65536 said:

I don't think anyone said it cannot fit? Just that it is meaningless. In fact there are published papers that propose exactly what you're saying, they're just not accepted as mainstream science, mainly because they don't account for everything that the accepted science does. Accepted science is always changing (usually slowly) but it changes to better account for actual observations, not imagined alternatives (unless it's a useful improvement). A lack of evidence doesn't prove your alternative doesn't fit, just that it doesn't improve anything.

What exactly does a constant metric of time account for that a non-constant metric of time doesnt?  AFAIK, GR doesn't even model the metric of time.   It just assumes that time over time is constant.  It is a fundamental premise of its theory, despite not explicitly stating it. The consequence of this assumption is that it effectively "normalises" the theory to a state where it works where time over time is constant - which of course suitably matches all observations because all observers are trapped in time with their observees.   Would a more fundamental model be one that includes a metric of time, albeit one that only matches observations when a solution to the metric of time for the observer is the same as that being observed.

Such a model could then interpret redshift as potentially also a stretching of the temporal axes, and not just the spatial axes.  While I agree it wont necessarily help with observations and won't be easy to test, its just an interpretation, like the Copenhagen vs Many Worlds interpretation of QM.

9 hours ago, md65536 said:

What it looks like to me, is that you're suggesting the possibility that instead of using GR to account for the universe as we observe it (where it fits very well for cosmology and large scales), we use it to account for something different than what we observe, and add in your proposals to account for the difference.

I'm saying that GR absolutely accounts for the universe we measure, because all measurements are trapped in time with whatever they are measuring and therefore it does not need to model a metric of time.   The universe we experience is one that measureably has a constant metric of time.

Should it (GR) account for something different than what we observe (measure)? Possibly, but that would be an end-result or a consequence that follows perhaps, rather than the reason to believe so.  The reasoning is that GR models spacetime as a single manifold with four dimensions, and with the discovery of redshift measurements, we accommodate this discovery by declaring that the spatial metrics are variable and the temporal metric is constant  - for (to me) no apparent evidence, knowing that those redshift measurements by necessity have the same time metric value as the EM waves being measured, which would allude to a constant metric time but not eliminate one that is non-constant.

Why should our measurements (of redshift) necessarily be accounted for only by expansion of space because the limitations in GR on the speed of light and the implicit invariant metric of time.  That is, the redshift shows that the receeding exceeds the speed of light, which violates GR, so there must be another mechanism at play; and implicitly, this moment of measurement of redshift is trapped in time with the EM waves themselves, which is a premise of GR.

I previously asked the question is there anything that exists that is observable but not (directly) measurable.  Perhaps it is possible the universe is more than just what can be measured? Or should we straight up dismiss it because it might not ever pass scientific methodology - "If it cant be seen today, it won't ever be seen in future and so its not there?"  That's some fallacious reasoning there.

We cant see the extra dimensions of string theory, let alone test them, yet I don't see us outright dismissing string theory.  Why should we dismiss a metric of time idea before we even have a mathematical model and before we know whether or not we can falsify it?  Surely that is more unscientific than a wild speculation with even just the slightest of reasoning.

##### Share on other sites

48 minutes ago, AbstractDreamer said:

I am using a principle of inheritance to say that without a model.   If you can demonstrate that you can drink a glass that is half full in one gulp, then the same glass that is half empty can also be drunk in one gulp without necessarily needing to demonstrate it - because the latter inherits all the properties of the former.   If a space expansion explanation of cosmological redshift does not affect the fine structure constant, then neither would a time-metric contraction explanation nor even a massless invisible gorilla explanation affect the fine structure constant.

That's simply not something you can assert as true until you have the models available to compare.

Because our model of space expansion has a caveat for gravitationally bound systems - an interaction that depends explicitly on distance. But not time. So you can't just swap them.

48 minutes ago, AbstractDreamer said:

I beg for precision.  We know the speed of light is invariant with a constant metric of time.  We know the speed of light is invariant using any frame of reference at the same moment as the measurement of that speed.  These premises are fundamental and intrinsic to the physics of GR.  You cant use a theory to prove its own premises!

No, but you can do tests that depend on these premises, and this happens repeatedly. The distinction being that we have models to inform us of what tests we can do.

Without a model as guidance, you can't come up with tests.

48 minutes ago, AbstractDreamer said:

In the same way we cant explain why there is no (or insignificant) space expansion in volumes of curvature.  It's just an observable the redshift only occurs in "flatter" volumes.  Anything you can say about why space expansion is observed the way it is can be similarly attributed to any alternative explanation of redshift.

No, as previously discussed, we know why no expansion is observed in those cases. We have a mechanism.

The time hypothesis lacks a mechanism.

48 minutes ago, AbstractDreamer said:

I have wildly speculated previously, the measuring of wavelengths are "trapped" in time with the waves themselves.   We literally cannot measure something yesterday or tomorrow.  We can measure something that was emitted yesterday and travelled a lightday through space to reach us.  But we can only measure it "right now".  If we did measure it yesterday,  it was measured "right then" and not "right now".   We cannot measure something "right now" as it was or will be at any other time than "right now".   The "fixing" of this time moment requires that the observer and the object be in the same moment.

We can measure a signal that was sent yesterday, and was a light-day away.

48 minutes ago, AbstractDreamer said:

But I propose that redshift is due to the continuum being stretched -  not just the space part.  It looks like the only the space part (wavelength stretching redshift) is changing because our observations are fixed in time with our objects.

And I will keep pointing out that this is meaningless without an actual model that tells us what is supposed to be happening, and why we only observe it happening with objects that are not close to us.

##### Share on other sites

3 hours ago, swansont said:

Because our model of space expansion has a caveat for gravitationally bound systems - an interaction that depends explicitly on distance. But not time. So you can't just swap them.

And I will keep pointing out that this is meaningless without an actual model that tells us what is supposed to be happening, and why we only observe it happening with objects that are not close to us.

In the same way that space expansion is explicitly dependent on distance, so too could the proposed time-metric-contraction equivalent - that is, dependent on distance not time.  There is no requirement that the dependency needs to be swapped.

In addition, is it not true that distance is explicitly intertwined with time?  The coordinate system for GR describes a spacetime value, not just a space value or a time value.  Anything that is far away in distance is ALSO far ago in time.  Something that is 10 lightyears away in distance is also a year away in time.  Something that is 20 lightyears away in distance is also twice the time away than something 10 lightyears away in distance.  Something that is 1 year ago has some value of distance away based on its motion and potential and background curvature.  Anything explicitly dependent on distance is also explicitly dependent on time, and vice versa.

So if space expansion is explicitly dependent on distance, is it not also possibly explicitly dependent on time under a specific coordinate rotation?

3 hours ago, swansont said:

Without a model as guidance, you can't come up with tests.

The concern for testability is not a reason to dismiss an idea before consideration, at least not before even a model is framed.  Once we have a model, you can argue it cant be tested.  Before that, we should be allowed to create a model.  Unless you already have all the answers.

3 hours ago, swansont said:

No, as previously discussed, we know why no expansion is observed in those cases. We have a mechanism.

Please elaborate what this mechanism is.  Is there any definitive proof why it must only stretch the spatial axes but the temporal axis must remain constant?

Edited by AbstractDreamer
##### Share on other sites

2 hours ago, AbstractDreamer said:

In the same way that space expansion is explicitly dependent on distance, so too could the proposed time-metric-contraction equivalent - that is, dependent on distance not time.  There is no requirement that the dependency needs to be swapped.

Except it’s not dependent upon distance when the distance is small.

2 hours ago, AbstractDreamer said:

The concern for testability is not a reason to dismiss an idea before consideration, at least not before even a model is framed.  Once we have a model, you can argue it cant be tested.  Before that, we should be allowed to create a model.  Unless you already have all the answers.

Testability is a requirement for it to be scientific

2 hours ago, AbstractDreamer said:

Please elaborate what this mechanism is.

Gravity. As has repeatedly been explained.

2 hours ago, AbstractDreamer said:

Is there any definitive proof why it must only stretch the spatial axes but the temporal axis must remain constant?

Nothing in science has definitive proof, so this is an artificial objection.

## Create an account

Register a new account