At Rest with our Hubble view

[Tach]

Tach, perhaps this has slipped past you but most scientific papers dealing with GR and SR deal with ideal and often unrealistic conditions. Especially where GR is concerned, attempting to deal with all of the real variables is an unrealistic endevor.

How would you know, you understand neither SR nor GR.

 

[wellwisher]

At rest with our Hubble view

What is wrong with the concept of "at rest" relative to the separating galaxies and generally constant microwave background radiation?

We observe the galaxies moving away from each other in all directions at an accelerating rate, and we measure the microwave radiation coming at us from all directions at a nearly constant frequency. These observations should be the same from any point in our Hubble view.

Given those two observations made from any point in space within our Hubble view, can we say that relativistic motion can be quantified relative to any point within the Hubble view?

The biggest problem with relative motion, is it can violate an energy balance, thereby creating or destroying energy so theory can appear to be right, even when based on perpetual motion.

For example, we have two rocket ships, one of mass M and the other of mass 2M (double the mass). They are in space moving relative velocity V, but without any way to know who is moving. Depending on how you proportion this velocity for each rocket, gives a range of system energies.

If the M ship has all the velocity, the system kinetic energy is 1/2MV2. But if the other ship has all the velocity the system kinetic doubles to MV2. If we pick wrong we add or take away energy to the universe, allowing special effects for a bad theory.

Special relativity had three equations, one each for mass, distance and time. The mass equation requires an energy balance. But the mass variable has been undermined, so we can create perpetual motion illusions with just distance and time. The twin experiment was chosen because their masses are the same, so reference is relative in this one special case without violating an energy balance; pretty girl to distract the crowd.

The way I avoid this realm of magic tricks, which people love, is to define a ground state for the universe. The most obvious is the speed of light which is the same in all references.

 

[OnlyMe]

Please drop the annoying, "what about a pendulum" or "what about a mechanical wrist watch". It is obvious that Tach was talking about atomic clocks. All common household clocks are calibrated to varying accuracies. Your watch, if you opened it up, has an adjustment in it. Pendulums are calibrated. Quartz clocks are calibrated. Even common electric alarm clocks that run on 60 Hz synchronous motors use the mains power 60Hz which is calibrated at the power company. For applications such as being discussed here, atomic clocks are called for. Even they are calibrated but the accuracy is many orders of magnitude better. ALways use the right tool for the job. Please stop this ignorant argument for argument's sake line of "reasoning".

Cheezle, referencing pendulum and spring wound clocks was to emphasize the absurdity of Tach's general statement(s). The same arguments can be made with atomic clocks. (See Aqueous' post quoted below and my comment)

You are correct that scientifically speaking neither, pendulum or spring wound clocks, are of much use given today's technology. That does not mean they cannot be good common examples of the situation.

As far as argument for argument's sake is concerned, that is what most of Tach's posts amount to, except that he has difficulty staying with the science and relies heavily on attempts at personal insult.

You speak as if there is no science dealing with measurement and calibration.

In one set of experiments, scientists raised one of the clocks by jacking up the laser table to a height one-third of a meter (about a foot) above the second clock. Sure enough, the higher clock ran at a slightly faster rate than the lower clock, exactly as predicted.

​

http://www.nist.gov/public_affairs/releases/aluminum-atomic-clock_092310.cfm

Aqueous, I am not certain but the article you cite above may refer to the experiment I referenced by passive recall, in post #313, the relevant portion quoted below. If not it is close enough that it serves the same purpose.

If I am not mistaken, the rate a light clock ticks at, has been experimentally observed as measurably different with as little as a one meter difference in height above the lab floor...

From the information in your reference, one would also have to conclude that all clocks on the surface of the earth do not tick at the same rate. Which is what Tach has been saying, based on a theoretical analysis of ideal conditions. The surface of the earth varies in both elevation and local gravity...

It was also just such a fact or reference that Farsight mentioned, in post #317,

The NIST optical clocks go slower when they're lower.

And then followed up in post #360 with,

This isn't strictly true, in that you could place light-clocks in an equatorial plane around the Earth, and plot the readings. The lower clocks go slower, and your plot exhibits a curvature.

The later of which Tach took exception to and began a personal attack. Both are statements supported by your article and NIST reference.

Again, I do not agree with most of Farsight's conceptual interpretation(s), that does not make any experiment or other reference he uses, or misuses invalid. Challenge the interpretation not the facts.

 

[Tach]

Cheezle, referencing pendulum and spring wound clocks was to emphasize the absurdity of Tach's general statement(s). The same arguments can be made with atomic clocks. (See Aqueous' post quoted below and my comment)

In reality it emphasizes your ignorance:

1. You chose to ignore a paper published in a peer reviewed journal (AmJPhys) declaring it "unrealistic".
2. You tried to move the goalposts (several times) , last time by introducing clocks that do not function correctly. The point was that all clocks that function correctly tick at the same rate. We are not talking about the imperfections in the clock construction causing de-synchronization, we are talking about well behaved clocks. Both I an Cheezle pointed out your attempt at twisting things.


Let me try and explain to you what the paper from AmJPhys is saying (though I highly doubt that you'll be able to follow the math). I will use simpler math than the one in the paper. Start with the Schwarzschild solution:

$$(c d \tau)^2=(1-r_s/r)(cdt)^2-dr^2/(1-r_s/r)-(rd\theta)^2$$

For a clock that doesn't move radially $$dr=0$$ so:

$$(c d \tau)^2=(1-r_s/r)(cdt)^2-(rd\theta)^2$$

The above can be rewritten as:

$$d \tau=dt \sqrt{(1-r_s/r)-( r \frac{d\theta}{dt})^2}=dt \sqrt{(1-r_s/r)-r^2 \omega^2}$$

where:

$$r_s$$ is the Schwarzschild radius
$$r$$ is the radial coordinate of the clock
$$\omega$$ is the angular speed of rotation
$$d \tau$$ is the proper period of the clock

For two clocks situated at radial distances $$r_1$$ and $$r_2$$ on the geoid:

$$\frac{d \tau_1}{d\tau_2}=\frac{\sqrt{1-r_s/r_1-r_1^2 \omega^2}}{\sqrt{1-r_s/r_2-r_2^2 \omega^2}}$$

Now, it can be seen that , when $$r$$ increases both terms intervening in the calculation of the proper period of the clock, i.e. $$1-r_s/r$$ and $$r^2 \omega^2$$ increase, so their difference stays constant. If I wanted to be absolutely rigorous about this, I would have used the Kerr, not the Schwarzschild , metric or I would have used the more complicated calculations from the AmJPhys paper cited. I would have also had to use the metric for a geoid, not for a sphere. The above is only a simplified explanation as to why all (well behaved) clocks tick at the same rate on the geoid.

Again, I do not agree with most of Farsight's conceptual interpretation(s), that does not make any experiment or other reference he uses, or misuses invalid. Challenge the interpretation not the facts.

This is an outright lie, you have been supporting Farsight's fringe claims from the get-go. Every time you post, you post stuff in support of fringe, "alternative" views.

 

[OnlyMe]

In reality it emphasizes your ignorance:

1. You chose to ignore a paper published in a peer reviewed journal (AmJPhys) declaring it "unrealistic".
2. You tried to move the goalposts (several times) , last time by introducing clocks that do not function correctly. The point was that all clocks that function correctly tick at the same rate. We are not talking about the imperfections in the clock construction causing de-synchronization, we are talking about well behaved clocks. Both I an Cheezle pointed out your attempt at twisting things.


Let me try and explain to you what the paper from AmJPhys is saying (though I highly doubt that you'll be able to follow the math). I will use simpler math than the one in the paper. Start with the Schwarzschild solution:

$$(c d \tau)^2=(1-r_s/r)(cdt)^2-dr^2/(1-r_s/r)-(rd\theta)^2$$

For a clock that doesn't move radially $$dr=0$$ so:

$$(c d \tau)^2=(1-r_s/r)(cdt)^2-(rd\theta)^2$$

The above can be rewritten as:

$$d \tau=dt \sqrt{(1-r_s/r)-( r \frac{d\theta}{dt})^2}=dt \sqrt{(1-r_s/r)-r^2 \omega^2}$$

where:

$$r_s$$ is the Schwarzschild radius
$$r$$ is the radial coordinate of the clock
$$\omega$$ is the angular speed of rotation
$$d \tau$$ is the proper period of the clock

For two clocks situated at radial distances $$r_1$$ and $$r_2$$ on the geoid:

$$\frac{d \tau_1}{d\tau_2}=\frac{\sqrt{1-r_s/r_1-r_1^2 \omega^2}}{\sqrt{1-r_s/r_2-r_2^2 \omega^2}}$$

Now, it can be seen that , when $$r$$ increases both terms intervening in the calculation of the proper period of the clock, i.e. $$1-r_s/r$$ and $$r^2 \omega^2$$ increase, so their difference stays constant. If I wanted to be absolutely rigorous about this, I would have used the Kerr, not the Schwarzschild , metric or I would have used the more complicated calculations from the AmJPhys paper cited. I would have also had to use the metric for a geoid, not for a sphere. The above is only a simplified explanation as to why all (well behaved) clocks tick at the same rate on the geoid.

Tach, do you have some reading comprehension problem? I never said that the paper did not serve the purpose that it was intended to. That would require more information than is available in the paper.

What I said,

Tach, the paper you cite addresses an ideal and unreal case.

was directed at the fact that the paper treats the earth as an ideal gravitating body. It does not take into account, that the Earth's gravitational field varies from one location to the next, without reguard to elevations. The earth is not a uniformly dense object. And mathematical explanations that are based on simplified uniform compositions, represent ideal and unrealistic conditions. While useful for teaching purposes, even discussion, they do not always describe the real world.

This is an outright lie, you have been supporting Farsight's fringe claims from the get-go. Every time you post, you post stuff in support of fringe, "alternative" views.

Again, do you have a reading comprehension problem? I have been specifically addressing references to basic facts or experiment, not Farsight's conceptual interpretation(s).

Address the substance of his conceptual argument, rather than references to experiment and known facts, and you would hear little or nothing from me... (Though your constant and insecure need to spend more time on personal comment and attack, would still leave me wondering.)

 

[Tach]

Tach, do you have some reading comprehension problem?

Not at all, yet you obviously do.

What I said, was directed at the fact that the paper treats the earth as an ideal gravitating body.

Nope, you definitely did not understand the paper. Not surprising.

It does not take into account, that the Earth's gravitational field varies from one location to the next, without reguard to elevations.

Actually, it does but you were unable to follow the math.

Address the substance of his conceptual argument, rather than references to experiment and known facts, and you would hear little or nothing from me...

This is what I was doing all alone, now, less trolling from you would be great.

 

[Farsight]

Your definition of spacetime seems different from GR then.

It's different to the "modern interpretation" of GR, which is different to the "Einstein's GR".

I think the GR notion is that natural motion through space follows the curvature of spacetime which is determined by matter/energy in accord with the EFEs; in GR there is a resulting natural geometry that determines the amount of curvature based on the amount of matter/energy that is influencing the body that is moving through the spacetime in that location.

Look carefully at what you said. The motion is through space. It isn't through spacetime. Spacetime is an all-times-at-once mathematical model. There's no motion through it. It's totally static. It isn't waht space is. So when light curves it can't be because spacetime is curved. It has to be because of what Einstein said, which is a curvature of light can only occur when the speed of light varies with position. Einstein never ever said light curves because spacetime is curved.

When you say the presence of matter/energy alters the properties of space, you are referring to what GR refers to as curved spacetime, aren't you

Kind of, in that inhomogeneous space is the reality that underlies curved spacetime. When you plot the inhomogeneity using parallel-mirror light-clocks, your plot is curved.

but you are denying the natural geometric cause?

What natural geometric cause? The cause is a concentration of energy usually tied up as the matter of a star. Not a curvature of an abstract mathematical space that's absolutely static and isn't the same thing as space.

Though you say you are on the spacetime side of the issue, you perspective of what Einstein's equations are defining is different, i.e. you refer to the elasticity of space instead of the curvature of spacetime. You see a difference between those two phrases.

Agreed. It's because I've read what Einstein actually said.

I would say you aren't on the side of spacetime. You are on the side that says there is more to curved spacetime than just geometry; you are saying that the effect that your light clocks expose is caused by an effect that is readily observable, time dilation caused by the difference in the strength of gravity at different altitudes, gravitational time dilation. Isn't that what you mean, it is gravity that is affecting the elasticity of space?

Not quite. What I mean is that a concentration of energy affects the surrounding space, this affect diminishing with distance from the star. The result is non-uniform inhomogeneous space, which you can detect via the equatorial light clocks. Then because space isn't uniform and homogeneous, light curves. Then because of the wave nature of matter, things fall down.

I refer to that side of the issue as the "energy density of space due to the presence of gravitational energy density" side, instead of the "geometry of spacetime" side. That perspective is that all space contains energy density. That energy density is from a history of the motion of matter based on the gravitational energy that is a characteristic of the presence of matter. As matter moves it leaves behind the waning gravitational wave energy density that is expanding away from it at all times and that I think equates to the pressure that you refer to.

Not quite. Einstein said "the energy of the gravitational field shall act gravitatively in the same way as any other form of energy". Matter only acts gravitatively because of the energy content. Think in terms of that jelly analogy.

 

[brucep]

The entire theory of relativity is derived from the Einstein Field Equations. Those equations are the same today as when Einstein derived them. The problem with you is you're always wrong and you're proud of it.

 

[Farsight]

Tach, I don't agree with Farsight on most of his interpretation of Einstein's words. That said your response above seems deliberately misleading...

It is. He's being dishonest.

Today's technology has already proven that clocks at different positions within a gravity well do record time at different rates. It is called time dilation.

It is. But try to think in terms of light clocks, and then parallel-mirror light clocks as per the gif: View attachment 6353. There's no time flowing between those mirrors. It's just light, moving.

The fact, of the affect that gravity has on clocks, which has been experimentally verified.., is not the same as the reason gravity affects clocks, which remains the subject of theory. Farsight's reasons for observed fact are not consistent with modern scientific consensus. The fact is.., well.., fact.

Look at the gif, observe the fact. Modern "scientific consensus" is not consistent with fact, or Einstein, who repeatedly said the speed of light varies with gravitational potential, and the SR postulate doesn't apply for GR.

 

[Markus Hanke]

It's different to the "modern interpretation" of GR, which is different to the "Einstein's GR".

Wrong again. "Einstein's GR" is exactly the same as modern GR. How could it be any different if the same field equations are used !

Spacetime is an all-times-at-once mathematical model. There's no motion through it. It's totally static.

Yes, and this is exactly what GR is. It models space-time, with world lines in it, at all places and all times. And since space-time is in general curved, so are the world lines. Our human senses can only perceive "slices" of that space-time, hence the illusion of movement and progression of time. In reality though space-time is static, and so are the world lines of all particles in it; but those world lines are curved in accordance with the geometry of the underlying space-time itself. It is precisely this relationship that GR describes. In doing so GR is a completely deterministic model, which is why it is so hard to reconcile it with quantum physics which is probabilistic in nature.

So when light curves it can't be because spacetime is curved.

This is a complete non-sequitur, and you yourself have explained why. Space-time is not just the collection of all points, but the collection of all events; hence it contains all points of a ray of light at all times. It simply becomes a static curve in four dimensions, of which we see "a slice at a time", like a movie in a cinema. The entire movie is on the reel, but you cannot see it in its entirety at once. The rate of progression of this "movie" is determined by the causal structure of space-time - each two events are separated not only spatially, but also in time, and that separation is exactly 1 second every 300,000km, which is constant for all observers. Therefore it is obvious that, when space-time is curved, so is the null geodesic which is traced out by light. It is a natural consequence of a curved space-time. No artificial mechanisms such as changes in permittivity and permeability of the vacuum are required or called for. The vacuum is exactly the same for all observers.

Einstein never ever said light curves because spacetime is curved.

This is just plain wrong. Here is the original publication by Einstein of his GR field equations :

http://nausikaa2.mpiwg-berlin.mpg.de/cgi-bin/toc/toc.x.cgi?dir=6E3MAXK4&step=thumb

He explicitly talks about space-time, its curvature, and how it is mathematically derived. He also explicitly states that GR does not make any predictions about processes in nature other than gravity, and says that he was wrong on this point in previous publications. The entire article contains no mention whatsoever of a varying speed of light. Go figure.

I had given this references previously, but you never replied to it.

Not a curvature of an abstract mathematical space that's absolutely static and isn't the same thing as space.

Of course not. It's space-time, not space. They are not the same. GR deals with space-time, as clarified by Einstein in his above publication, and by the very simple fact that all indices in the tensor equation run 0...3.

Then because space isn't uniform, light curves.

Yet you cannot show us where in the EFEs this relation for varying speeds of light is hidden, and nowhere is this mentioned in Einstein's publication of the field equations. Furthermore, your variable speed of light does not actually explain any gravitational interactions, like perihelion precession, frame dragging, the n-body problem etc etc. It is simply nonsense.

Then because of the wave nature of matter, things fall down.

What complete and utter nonsense. GR says nothing about "wave nature of matter", or it being the cause of objects falling down. No such things appears anywhere in GR, and they make no physical sense at all. Einstein himself made it clear in the reference given above that GR does not deal with anything else but gravity, so certainly not with the nature of matter. Energy in all its forms only functions as the source term for gravity in GR, but GR makes no statements about their nature.
It is becoming more and more clear now that you are just proliferating your own crank theory here; this really shouldn't even be allowed to appear in the main sections of a science forum.

Modern "scientific consensus" is not consistent with fact,

Modern scientific consensus is that GR is about space-time curvature, meaning that all clocks are equally effected, regardless of whether they are "light clocks" or not. A grandfather clock would show the same, if it had sufficient accuracy; so would digital clocks, and atomic clocks, and lifetimes of fundamental particles. Time dilation is independent of the clock mechanism. And this is perfectly consistent with experimental facts. Saying that modern consensus is not consistent with facts is a blatant lie, and intellectually dishonest.

 

[Farsight]

No you haven't.

Yes I have.

Post 158 contains an animated GIF which has no relation to physical reality;

Yes it does. The NIST optical clock runs faster when it's 30cm higher. The same applies to parallel-mirror light clocks.

it is just a pictorial representation of your erroneous assertions, all of which have been addressed to death.

No they haven't, they've been dismissed, not addressed.

Wrong :
http://math.ucr.edu/home/baez/gr/stress.energy.html
http://www.nicadd.niu.edu/~bterzic/PHYS652/Lecture_03.pdf
http://www2.warwick.ac.uk/fac/sci/physics/current/teach/module_home/px436/notes/lecture6.pdf
MTW's Gravitation, Chapter 5.2

Shear stress features in the SEM tensor Markus. End of story. Throwing out a bunch of links doesn't impress anybody, and is no substitute for an argument.

Wrong again :
http://en.wikipedia.org/wiki/Einstein_tensor
http://math.ucr.edu/home/baez/einstein/node10.html
http://www.nicadd.niu.edu/~bterzic/PHYS652/Lecture_03.pdf
MTW's Gravitation, Page 40 onwards

As above. What the hell do you think metric means?

...which brings us back to the original problem - if the local speeds aren't the same across different regions of space, as in the vicinity of the sun, we would see frequency-dependent refraction effects along the global trajectory of a ray of light grazing past a massive body. Needless to say these aren't observed, so you are manifestly wrong. Thanks for pointing that out once again.

And again, refraction in glass does not occur because c varies, so yours is a total straw-man assertion.

Blatant lie. Not even once have you shown us exactly how the EFEs give us a relation for a varying speed of light. You have completely ignored the question.

No I haven't. I've said repeatedly that Einstein gave a local description. And you know full well that the coordinate speed of light varies in a non-inertial reference frame. A gravitational field.

What you have blown away is the illusion that you understand basic high school physics, such as Snell's law.

What I've blown away is your credibility. You have made it crystal clear that you duck and dive and dismiss instead of responding sincerely to the points raised. You still fight shy of addressing post #158. Your measurements exhibit a curvature when you plot them. Meanwhile you always measure the local speed of light to be the same because of the wave nature of matter. When light goes slower you and your light clock is going slower too, so you still measure 299,792,458 m/s. But the seconds aren't the same, so two speeds aren't the same. It's all really simple, it's in line with Einstein, and with the hard scientific evidence. Please try to address it in a logical fashion, and when you can't counter it, try to avoid saying things like "blatant lie".

 

[Farsight]

This might be interesting then:
http://www.google.co.nz/url?sa=t&rc...dvqxbvhVHFvU51g&bvm=bv.48705608,d.dGI&cad=rja

He's got it back to front. The coordinate speed of light is lower at lower elevations. At a black hole event horizon, it's zero. The expanding universe can be likened to pulling away from a black hole - the speed of light increases over time rather than decreasing. Magueijo made the same mistake, see wiki.

 

[Markus Hanke]

At a black hole event horizon, it's zero.

Wrong. In Schwarzschild space-time, "coordinate speed" is not even defined at the event horizon !

 

[brucep]

Wrong again. "Einstein's GR" is exactly the same as modern GR. How could it be any different if the same field equations are used !



Yes, and this is exactly what GR is. It models space-time, with world lines in it, at all places and all times. And since space-time is in general curved, so are the world lines. Our human senses can only perceive "slices" of that space-time, hence the illusion of movement and progression of time. In reality though space-time is static, and so are the world lines of all particles in it; but those world lines are curved in accordance with the geometry of the underlying space-time itself. It is precisely this relationship that GR describes. In doing so GR is a completely deterministic model, which is why it is so hard to reconcile it with quantum physics which is probabilistic in nature.



This is a complete non-sequitur, and you yourself have explained why. Space-time is not just the collection of all points, but the collection of all events; hence it contains all points of a ray of light at all times. It simply becomes a static curve in four dimensions, of which we see "a slice at a time", like a movie in a cinema. The entire movie is on the reel, but you cannot see it in its entirety at once. The rate of progression of this "movie" is determined by the causal structure of space-time - each two events are separated not only spatially, but also in time, and that separation is exactly 1 second every 300,000km, which is constant for all observers. Therefore it is obvious that, when space-time is curved, so is the null geodesic which is traced out by light. It is a natural consequence of a curved space-time. No artificial mechanisms such as changes in permittivity and permeability of the vacuum are required or called for. The vacuum is exactly the same for all observers.



This is just plain wrong. Here is the original publication by Einstein of his GR field equations :

http://nausikaa2.mpiwg-berlin.mpg.de/cgi-bin/toc/toc.x.cgi?dir=6E3MAXK4&step=thumb

He explicitly talks about space-time, its curvature, and how it is mathematically derived. He also explicitly states that GR does not make any predictions about processes in nature other than gravity, and says that he was wrong on this point in previous publications. The entire article contains no mention whatsoever of a varying speed of light. Go figure.

I had given this references previously, but you never replied to it.



Of course not. It's space-time, not space. They are not the same. GR deals with space-time, as clarified by Einstein in his above publication, and by the very simple fact that all indices in the tensor equation run 0...3.



Yet you cannot show us where in the EFEs this relation for varying speeds of light is hidden, and nowhere is this mentioned in Einstein's publication of the field equations. Furthermore, your variable speed of light does not actually explain any gravitational interactions, like perihelion precession, frame dragging, the n-body problem etc etc. It is simply nonsense.



What complete and utter nonsense. GR says nothing about "wave nature of matter", or it being the cause of objects falling down. No such things appears anywhere in GR, and they make no physical sense at all.

He can't figure out the difference between frame invariant measurements and frame dependent measurements. The local frame invariant coordinate speed of light and the frame dependent remote coordinate speed of light. He's going to always make mistakes because he's never made any meaningful attempt to really understand relativistic physics. It's annoying when cranks try to put words in Einstein's mouth.

 

[Markus Hanke]

The NIST optical clock runs faster when it's 30cm higher.

So do all clocks, regardless of mechanism.

No they haven't, they've been dismissed, not addressed.

There is nothing to be addressed there. The GIF has no physical meaning, as simple as.

Shear stress features in the SEM tensor Markus.

Of course it does, because it is a form of energy and hence a source of gravity. Nothing to do with "elasticity of space".

As above. What the hell do you think metric means?

We are not talking about metrics. We are talking about the Einstein tensor, and your ludicrous assertion that it is has anything to do with measurements and plots. It doesn't. It is a covariant curvature tensor, and its definition is quite independent of any system of coordinates.

And again, refraction in glass does not occur because c varies, so yours is a total straw-man assertion.

Right. So you are saying

1. Snell's law is wrong
2. Glass is optically indistinguishable from vacuum

Nice

I've said repeatedly that Einstein gave a local description.

This is precisely what I asked you for - a local function for the speed of light, and how it varies locally from point to point. You haven't given any.

What I've blown away is your credibility. You have made it crystal clear that you duck and dive and dismiss instead of responding sincerely to the points raised. You still fight shy of addressing post #158. Your measurements exhibit a curvature when you plot them. Meanwhile you always measure the local speed of light to be the same because of the wave nature of matter. When light goes slower you and your light clock is going slower too, so you still measure 299,792,458 m/s. But the seconds aren't the same, so two speeds aren't the same. It's all really simple, it's in line with Einstein, and with the hard scientific evidence. Please try to address it in a logical fashion, and when you can't counter it, try to avoid saying things like "blatant lie".

Your continued repetition of this does not make it any less wrong, you know. GR still has nothing to do with speeds of light, or wave nature of matter. GR is purely about gravity as a manifestation of space-time curvature. Would you like a few more references for this ? Every gravitational phenomenon we observe is entirely consistent with a curved space-time; nothing you do or say invalidates this simple fact. The same can not be said of your variable speed of light, as demonstrated.

 

[Markus Hanke]

He can't figure out the difference between frame invariant measurements and frame dependent measurements. The local frame invariant coordinate speed of light and the frame dependent remote coordinate speed of light. He's going to always make mistakes because he's never made any meaningful attempt to really understand relativistic physics. It's annoying when cranks try to put words in Einstein's mouth.

Yeah, how right you are. I think no one here has any hope of Farsight ever giving up his misconceptions; they're too deeply rooted at this stage. That doesn't mean though that we can't continue to call his bluff, and have some fun along the way
I just really think this shouldn't be in the mainstream section of the forum - it's just silly crackpottery.

 

[Farsight]

Wrong again. "Einstein's GR" is exactly the same as modern GR. How could it be any different if the same field equations are used !

Because modern GR says the speed of light is constant whilst Einstein said the speed of light varies with gravitational potential. Because modern GR says light curves because spacetime is curved, whilst Einstein said light curves because the speed of light varies with position. It's that simple. Now go look at the Einstein quotes and the gif and stop being so dismissive.

Yes, and this is exactly what GR is. It models space-time, with world lines in it, at all places and all times.

Wrong! Spacetime is part of the model. GR models energy and space and motion.

And since space-time is in general curved, so are the world lines. Our human senses can only perceive "slices" of that space-time, hence the illusion of movement

Illusion of movement? Markus, movement is no illusion. It's real. I can waggle my hands and say this is motion. You can't show me spacetime, because it's just an abstract thing used in a mathematical model.

and progression of time. In reality though space-time is static, and so are the world lines of all particles in it; but those world lines are curved in accordance with the geometry of the underlying space-time itself.

There is no underlying spacetime in any real sense. Motion is real, it is empirical. I can waggle my hands and show you motion. You can't show me spacetime. You know it can't be real because it's static, and my hands aren't.

It is precisely this relationship that GR describes. In doing so GR is a completely deterministic model, which is why it is so hard to reconcile it with quantum physics which is probabilistic in nature.

IMHO it's hard to reconcile GR with QM because people do not understand the distinction between a model and reality.

This is a complete non-sequitur, and you yourself have explained why. Space-time is not just the collection of all points, but the collection of all events; hence it contains all points of a ray of light at all times. It simply becomes a static curve in four dimensions, of which we see "a slice at a time", like a movie in a cinema. The entire movie is on the reel, but you cannot see it in its entirety at once. The rate of progression of this "movie" is determined by the causal structure of space-time - each two events are separated not only spatially, but also in time, and that separation is exactly 1 second every 300,000km, which is constant for all observers. Therefore it is obvious that, when space-time is curved, so is the null geodesic which is traced out by light. It is a natural consequence of a curved space-time. No artificial mechanisms such as changes in permittivity and permeability of the vacuum are required or called for. The vacuum is exactly the same for all observers.

Markus, get real. The world is not some movie reel that you can only see one frame at a time.

This is just plain wrong. Here is the original publication by Einstein of his GR field equations :

http://nausikaa2.mpiwg-berlin.mpg.de/cgi-bin/toc/toc.x.cgi?dir=6E3MAXK4&step=thumb

He explicitly talks about space-time, its curvature, and how it is mathematically derived. He also explicitly states that GR does not make any predictions about processes in nature other than gravity, and says that he was wrong on this point in previous publications. The entire article contains no mention whatsoever of a varying speed of light. Go figure.

It's in German. neat trick Markus. And it's dated 1915. In 1916 Einstein was still referring to the variable speed of light. Even in the Foundation of the General Theory of Relativity he says the SR postulate doesn't hold.

I had given this references previously, but you never replied to it.

Not deliberately. Can you point me towards an English translation of it? I can read bits of German, but it's a struggle.

Of course not. It's space-time, not space. They are not the same.

Exactly. That's why the space around the Earth isn't curved.

GR deals with space-time, as clarified by Einstein in his above publication, and by the very simple fact that all indices in the tensor equation run 0...3.

No problem with that. But space-time is not the same as space. You think the space around the Earth is curved. It isn't. It's inhomogeneous. Has the penny dropped yet?

Yet you cannot show us where in the EFEs this relation for varying speeds of light is hidden, and nowhere is this mentioned in Einstein's publication of the field equations. Furthermore, your variable speed of light does not actually explain any gravitational interactions, like perihelion precession, frame dragging, the n-body problem etc etc. It is simply nonsense.

When are you going to stop dismissing what Einstein said as nonsense? I'm not making up those quotes.

What complete and utter nonsense. GR says nothing about "wave nature of matter", or it being the cause of objects falling down. No such things appears anywhere in GR, and they make no physical sense at all. Einstein himself made it clear in the reference given above that GR does not deal with anything else but gravity, so certainly not with the nature of matter. Energy in all its forms only functions as the source term for gravity in GR, but GR makes no statements about their nature.

I never said GR deals with the wave nature of matter. Now go and take a look at what you said about reconciling GR and QM. And what I said too.

It is becoming more and more clear now that you are just proliferating your own crank theory here; this really shouldn't even be allowed to appear in the main sections of a science forum.

Pah. It's becoming more and more clear now that I have bested you, and now you're squealing and trying to impose censorship.

Modern scientific consensus is that GR is about space-time curvature, meaning that all clocks are equally effected, regardless of whether they are "light clocks" or not. A grandfather clock would show the same, if it had sufficient accuracy;

And again you betray your lack of physics knowledge. Grandfather clocks aren't the same as other clocks. Their tick rate depends on the local slope of gravitational potential, not gravitational potential.

so would digital clocks, and atomic clocks, and lifetimes of fundamental particles. Time dilation is independent of the clock mechanism. And this is perfectly consistent with experimental facts.

Keep digging Markus. You can apologise later and earn some brownie points for admitting you were wrong.

Saying that modern consensus is not consistent with facts is a blatant lie, and intellectually dishonest.

Oh no it isn't. Now go and look at the gif and those Einstein quotes instead of accusing me of intellectual dishonesty.

 

[Farsight]

Yeah, how right you are. I think no one here has any hope of Farsight ever giving up his misconceptions; they're too deeply rooted at this stage. That doesn't mean though that we can't continue to call his bluff, and have some fun along the way

I'm the one having fun here Markus. You're the one who's squealing.

I just really think this shouldn't be in the mainstream section of the forum - it's just silly crackpottery.

No, it isn't. Instead your movie-reel static "reality" is. The illusion of motion. LOL. Lordee save us from self-appointed "experts" who can't stand being challenged, and who call for censorship when they're losing the argument.

Now go and check out the grandfather clock, and then you can gain some credibility by saying actually Farsight is right about that. If you won't do this kind of thing, it doesn't help your case.

 

[PhysBang]

I'm the one having fun here Markus. You're the one who's squealing.

Yes, you certainly are having fun, making yourself look important while not actually doing any physics. While you lie about always answering questions, you seem to have avoided the real questions that I raised about the perihelion shift of Mercury and the rotation curves of galaxies. Like Markus saysm you will bever answer those questions because it would show your lies.

How about this seemingly easy question, which I notice that you have avoided answering in other places: How is it that waggling your fingers demonstrates motion?

 

[quantum_wave]

Certainly GR is what it is. I'm as amazed that so many people consider it to be Reality, as those people probably are that everyone doesn't see it that way.

I'll generalize here by saying that "we", science enthusiasts, all seem to think everyone would believe like we believe if they had the same degree and quality of knowledge as we have. Of course every one's degree and quality of knowledge is not the same, and so we believe differently. Science is more factual than the undisciplined and uneducated views, but within a healthy, disciplined, and educated scientific community there is the mainstream view and the alternative views.

My view of reality is still evolving and so I believe that yours should be too if you are not deluded, so let's try to be persuasive in our arguments and tolerant of other's arguments. A thread like this draws out different views and I encourage discussion and argument in favor of our views, but those discussions don't need to get off on disparagement of each other. Who wants to carry on a one sided civil argument with someone who follows no civil rules of discussion in return? If you can't convince someone, you can stop trying instead to turning it into personal attacks.

So, that said, GR is not Reality, and Science does not portray it as such. Those who insist it is are deluded, maybe even more deluded than those of us who form our own alternative views.