AbstractDreamer

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

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. 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. 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. 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.

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

Feel free to be helpful and explain where I'm wrong. The evidence is cosmological redshift. Can you explain why space expansion is a compelling model and makes more sense?

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? 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.

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? 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? 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.

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?

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?

While this is a sensible statement rooted in logic, it's not a universal law or principle afaik. Is there any way to test Hawking Radiation at the event horizon on the black hole? Does it have a measurable effect? Is there any way to test space expansion at the edge of our observable universe? Does it have a measureable effect?

Ha! I honestly struggle making sense of it myself, definitions in words is very difficult, and my maths is school boy level so I cant model anything. But I think overall we are grasping at the same concept. Let's say that this notion of "time over time" is NON-constant. What I mean by this is that the "rate that time propagates" is different at two different values of time, relative to a theoretical frame of reference that is "outside" or "independent" of time. Now clearly there is no such frame of reference in reality. Everything in our spacetime is intrinsically bound within time. Hence it is a theoretical, or imaginary frame of reference. But that the frame is suitably "static" relative to both events in time. So let's say that one second, today at time t=13.8B years, is defined by caesium frequency of caesium atoms that exist at time t=13.8B years. Let's imagine at time t=1 year that caesium atoms exist, and 1 second is again defined by caesium frequency of caesium atoms that exist at time t=1 year. So then you measure the speed of light in units of "distance per caesium frequency". Assuming distance is constant (this is another problem), then both today and at t=1 year, both measurements would arrive at the same result - relative to the caesium frequency of that time. But if somehow you compared the two caesium frequencies, using a measure and a frame of reference independent of both time today and time 1 year, then a "non-constant time over time" would allow the two frequences to differ - and yet nothing need be violated for either of the two events, within their respective time. I'm really not sure how to respond to those three points and how they might relate and where I might disagree. Those three points are total valid, but there are practical limitations implied within them. Point 2 is about measuring time. My point accepts that measuring is currently experimentally impossible. Point 3 is about using the clock as its own frame of reference. This is different to a frame of reference independent of time.

Thank you for such precise answers to my questions! I shall digest them thoroughly. My biggest enlightenment was learning that a Schwarzschild BH have very exact requirements... can I argue it is a physically improbable in our real universe - to have a black hole that exists in perfectly flat, albeit possibly hyperbolic, spacetime? Is it also true that flat Minkowski space is similarly improbable in our real universe?

How would you test for constant time?

There is no evidence that "non-constant function of time over time" doesn't work. GR, experimentally, works with "non-constant function of time over time" too. Would you agree with the above statements?

So "Schwarzschild spacetime is entirely empty vacuum everywhere", but Schwarzschild spacetime is not necessarily uniform or symmetrical? For example a source of significant curvature on one side, external of the blackhole would create asymmetry of the spacetime beneath the EH? So in a circumstance when spacetime is significantly asymmetric under the EH around the singularity, and when spacetime is significantly asymmetric above the EH around the black hole; would a non-rotating Schwarzschild blackhole still appear perfectly spherical?

Because is it possible that a "non-constant time function over time" could model observed space expansion? It would remain experimentally untestable, unless your experiment spanned a volume of space time that contained such expansion, yet somehow remained unaffected by the expansion. I cant really grasp the scale that expansion works on, but I would wildly guess that it appears to me to break homogeneity at least on a scale reasonable local to expansion. Of course the argument for homogeneity is to choose a larger scale. If spacetime is a continuum, then homogeneity in space is also homogeneity in time. How do we can reconcile homogeneity in time, when we have a universe that apparently expands locally or globally, or at least inflated globally? It's appearance and properties shortly after t=0 is much different that today. In the same way that GR has no evidence to support that time is constant over time? Not sure how this relates at all. What is the principle in GR that assumes time is constant over time? I don't think there is one. Indeed it doesn't need one... experimentally. However it does assume this, right? On a similar notion, what evidence do we have that any unit is constant over itself? Take distance for example. At a large enough scale that experiences significant expansion, something that measures D units using measurements within that expansion, might measure D+E relative to observations from without that expansion. What is the principle of realism that states non-theoretical units are uniform from zero to infinity?

So anything crossing into the EH joins/shares its charge, mass, angular momentum with the single entire entity of the blackhole? Does a black hole experience gravitation from objects outside its EH? If some nearby spacetime is curved by some other object, does this curvature extend beyond the EH? As a graviton wave crosses into the EH, does the black hole grow in energy? Which if any of its properties will change? If the black hole was of sufficient "volume? surface area?" where the external curvature at one location was significantly different from the other "side?", and taking the blackhole as a single non-quantisable entity, would this cause one part of the black hole to "move" in a different direction to another part of the black hole? Would this cause pressure or stress within the black hole?

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? 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?

Thank you for this, but I'm not talking about motion or potential. Or either of them changing over time.

The first question was whether GR is premised on time being constant The second question was if there is any basis that time is constant. Both questions are about time being constant over time, which I believe you have either misunderstood or ignored, hence your answer about time being dependent on your motion relative to another observer, and on your gravitational potential. With respect, you are repeatedly selecting only some of my questions, and then providing answers that do not relate to those questions.

So you are saying categorically it (time) cannot depend on anything else, such as for example a function of itself? Which of my questions is "no" the answer to? How do the equations in GR allow for Proper Time that has a world line that spans two manifolds between which have observed space expansion?

So do the equations of General Relativity premise on the propagation of time being constant since the Big Bang? That is, the premise that the axes of time are uniform between t=0 and t=infinity. Is there any logical or reasonable basis upon which to assume that the propagation of time is a constant since the Big Bang? If we accept that the spacetime continuum experiences a stretching of its axes when observing space expansion, why should we assume that its only the axes of space that is stretched, and that the axes of time remain uniform?

I have read that Blackholes have properties Mass, Charge and Angular Momentum, and that the Event Horizon is the boundary between where spacetime is curved so much that all paths converge, and between where there are some paths that could diverge. Putting aside Hawking Radiation, apparently "nothing?" can leave the EH. As far as I understand, the "nothing" refers to anything with mass and any form of electromagnetism such as light, and perhaps categories of other things. So if electromagnetic waves cannot exit the EH, how does the charge of the Blackhole create the electromagnetic effect that propagates around the black hole due to that charge? Likewise with mass and curvature, how does the density of the mass "inside" the black hole's EH manage to curve the space time outside the EH, if the EH is a boundary where all paths converge? If you were a bit mass under the EH, and you tried to emit your gravitational wave through the EH, that wave would have a geodesic that remains within the EH. If that wave never exits the EH, and if ALL waves never exit the EH, what is causing the gravitational effect of the blackhole as experienced by objects outside the EH?

It didn't think it does matter. That's why I'm asking questions. If learned minds can also agree it doesn't matter, I'll take it as a reasonable basis to continue using it as a premise to my end question about dark energy. It's meaningless perhaps today from anything directly measurable within spacetime. But theoretically, would you agree there if there is a conceptual idea of the rate of change of time, that there is no basis to assume it is constant at different moments/periods in time? Something is seemingly stretching the axes of spacetime. With a leap of faith, it is possible this entity is outside of time? What if this entity was not directly measurable, but its effect on the measurable universe CAN be observed. We can observe space expansion occurring in the measurable universe, it is possible that we cannot directly measure what is causing it? Can we directly measure a singularity? I don't think so. A singularity exists outside of spacetime as its gravitational potential is undefined. Can we observe the effects of a singularity? Maybe not. What exactly does a singularity do? Perhaps we cant measure dark energy directly. Perhaps dark energy is outside of spacetime as it's motion is undefined. Perhaps its effect can be observed through spacetime expansion. Is it possible that singularities are the source of dark energy?

Right, we can't notice it! We are all "trapped" in the same rate of change of time. The unit of time could be doubling, halving, exponential, logarithmic. We would not be able to observe it, and it would have not consequence to anything within our spacetime. If there is no theoretical or experimental evidence that this is the case, then why should there be theoretical or experimental evidence that this isn't the case? What basis do we have to assume the rate of time is constant? So it doesn't really break any theories to consider the rate of time as non-constant, as it is not measurable. So why not pick an arbitrary function of this rate of time and tie it into dark energy with undefined motion, to explain space expansion? What are the main arguments that oppose this approach?

Yes, I think that is my question. And no, I don't think it matters at all to the standard model. Which is why I'm asking the question... if it doesn't matter, what are the theories that follow if the "unit" of time does or does not change, as time progresses. And can dark energy exist outside of time. And in the possibility that dark energy can exist outside of time, could it cause or be caused by time accelerating? I accept that the passing of time is relative, and therefore it changes. That is, time dilates. But this argument does not refute my question. My question is more: For a situation where the effect of time dilation due to relative motion is zero, is there no possibility that the rate of change of time is variable - specifically, a rate that has a denominator value "outside" of time. Undefined motion akin to gravitational potential at a singularity. Do singularities have undefined gravitational potential? Would this mean singularities exist "outside" of time? Black holes will eventually decay, but what happens to the singularity? My choice of the word "speed" is poor. I should have said "rate of change per something else". Density is mass/volume. If mass increases, it is denser. Speed is distance/time. If distance increases, it is faster. "rate of change of time per Gap" is time/Gap. If time increase, it is more "rate of change of time per Gap" But I don't think it needs to be another clock. It just needs to be another unit, measureable or not. But for conceptual purposes, lets call it Imaginary Time or iT, where iT is orthogonal to T. It relates via my wildly speculative question about variable rate of time and space expansion - that is, whether it is possible that the unit of time changes over time with respect to a unit of something else outside of time. And, if there are entities that exist outside of time (such as an imaginary entity with undefined motion), could they be linked to dark energy somehow. And ultimately, could something like a variable rate of time be the cause or the effect of space expansion.