The Speed of Light is Not Constant

[arfa brane]

That is why the local GR reality in that specific two-clock above one another scenario TRUMPED the abstraction overlays from 'frames' theories/analysis/views.

And what makes you look stupid is that "one clock above the other" makes sense only because they're in a gravitational field which has a direction in space. So the fact that you know how to distinguish "above" in relation to two clocks means they aren't freely floating in space, where "above" is meaningless.

So the clocks must be a finite distance from each other and each is in its own frame of reference, defined by the field direction and potential.
So you're an idoit.

Unless of course the field direction is just another abstract "overlay", or the field itself doesn't correspond to "reality", or maybe the strength of the field is just a number, etc.

 

[Aqueous Id]

I understand all this. I also understand that a reference frame isn't something you can point out in the clear night sky. In the SR context, it's little more than a "state of motion".

Only if you delete the words 'frame of reference' and insert 'state of motion'.

 

[Undefined]

And what makes you look stupid is that "one clock above the other" makes sense only because they're in a gravitational field which has a direction in space. So the fact that you know how to distinguish "above" in relation to two clocks means they aren't freely floating in space, where "above" is meaningless.

So the clocks must be a finite distance from each other and each is in its own frame of reference, defined by the field direction and potential.
So you're an idoit.

Unless of course the field direction is just another abstract "overlay", or the field itself doesn't correspond to "reality", or maybe the strength of the field is just a number, etc.

What is the matter with you, arfa? Is there nothing which you and others will NOT complicate unnecessarily by invoking UNREAL THINGS maths/abstractions which are UNNECESSARY by the very setup of the two clocks one above the other in REAL SPACE and not in some esoteric maths-land world where you need 'frames' to tell you which clock is above the other IN THE SAME ROOM with you?

Good grief, mate, where does the fantasy stop intruding into the simple reality under your nose?

Get it?

I don't need to know what 'frame' each clock is in. I only need to place them and see what transpires over the year as to respective cumulative counts in their registers.

GR ALREADY PREDICTS that in gravity wells the tick rate (and hence counts accumulation) will DIFFER if they are in different altitudes in a gravity well.

IF the counts DO differ, then we will KNOW BY GR PREDICTION that the clocks INDEED MUST have been in different altitudes in that same room. There is no need to 'call' that differrent altitudes 'frames', because the GR EFFECTS are predicted and self-explanatory/consultable directly comparing the clock counts and inferring that GR must explain the differences IF there are any when compared the counts.


Where does the fantasy world intrusion stop such that you can actually consult the SELF-EVIDENT REALITY once in a while like in THIS SPECIFIC SCENARIO?

Please don't come back again with the obvious and the IRRELEVANT, mate. Not needed here. Thanks.

 

[Aqueous Id]

And what makes you look stupid is that "one clock above the other" makes sense only because they're in a gravitational field which has a direction in space. So the fact that you know how to distinguish "above" in relation to two clocks means they aren't freely floating in space, where "above" is meaningless.

Farsight space is not the same as arfa space. It just can't tolerate the indignity of being measured.

Unless of course the field direction is just another abstract "overlay", or the field itself doesn't correspond to "reality", or maybe the strength of the field is just a number, etc.

In farsight space there need not be any geometry at all. The rules of nature are dictated by imposing the abstract overlay of one person's beliefs about geometry onto the world. It does present a bit of difficulty though since you need a farsight transformation matrix to interpret the results, but at least it greatly expands the number of possible states the world can be in. Just in case anybody else needs rhetorical evidence to shore up the fundamentalist argument that science is fundamentally broken.

Oops I meant RealityCheck. Same same.

 

[arfa brane]

GR ALREADY PREDICTS that in gravity wells the tick rate (and hence counts accumulation) will DIFFER if they are in different altitudes in a gravity well.

IF the counts DO differ, then we will KNOW BY GR PREDICTION that the clocks INDEED MUST have been in different altitudes in that same room. There is no need to 'call' that differrent altitudes 'frames', because the GR EFFECTS are predicted and self-explanatory/consultable directly comparing the clock counts and inferring that GR must explain the differences IF there are any when compared the counts.

GR does indeed predict that clocks at different altitudes will tick at different rates.

You think this means you don't need to define frames of reference, but that's exactly what altitude in a gravity well is, a frame of reference in which "above" makes sense; the gravitational field 'defines' the frame, there is nothing you can do about this.

In a space with no gravitational field, altitude is nonexistent and so is any difference in clock rates, but frames of reference, positions and directions, still exist.
Whether you call different altitudes (gravitational potentials) "frames" is up to you, but that's what physicists call them.

 

[Undefined]

GR does indeed predict that clocks at different altitudes will tick at different rates.

You think this means you don't need to define frames of reference, but that's exactly what altitude in a gravity well is, a frame of reference in which "above" makes sense; the gravitational field 'defines' the frame, there is nothing you can do about this.

In a space with no gravitational field, altitude is nonexistent and so is any difference in clock rates, but frames of reference, positions and directions, still exist.
Whether you call different altitudes (gravitational potentials) "frames" is up to you, but that's what physicists call them.

Finally! You just said it yourself: "...the gravitational field 'defines' the frame"

That's what I have been telling YOU. The GR reality is PRIMARY and any 'overlay' of 'frames' etc superfluous considerations (other than that primary REAL GR positions consideration) is SECONDARY abstract overlay and in this specific exercise MOOT.

And don't fall for that strawman Aqueous Id and others are trying to 'convince' you of saying that I don't know what a co-ordinate frame is or how it is used in Relativity. I do, Obviously! The point I am trying to make is that in this scenario it doesn't matter what unreal co-ordinate frame overlays are. They are NOT needed here, that's all. Don't let A Id et al snow you into being distracted by their personal/trolling tactics. Just read the full thread/context for yourself.

I said before, this is NOT a case of discussing the 'wider meaning/uses' of co-ordinate frames; it is a specific scenario simplifying the setup essential relevant aspects to the real self-evident GR context/outcome. Period.

No further 'general discussion' of coordinate frames views/analyses/overlays/interpretations involved in seeing/comparing the actual real counts of the clocks. That tells us that the two light clocks were ticking/counting at different rates, hence different counts cumulative. Period.


NOW the question/discussion between Farsight and Russ et al is what and why the light clock 'between mirror' light travel WAS different rate of travel to give the different reflection-back-and-forth rates?

That is where the reality and the theory come face to face with their own 'interpretations' of what the light is doing and whether it is that abstract 'spacetime length' or actual light speed that has 'varied'?

I will read that further discussion with interest. Good luck, guys!

 

[arfa brane]

Finally! You just said it yourself: "...the gravitational field 'defines' the frame"

That's what I have been telling YOU. The GR reality is PRIMARY and any 'overlay' of 'frames' etc superfluous considerations (other than that primary REAL GR positions consideration) is SECONDARY abstract overlay and in this specific exercise MOOT.

But, the clocks are at different heights so they are at different potientials. The potentials determine the difference in clock rates; the field strength is known and it's trivial to measure the height of each clock.

You're missing the point that although the clocks are ticking at different rates, this is completely determined by the field strength and where each clock is. You get back the information from the clock readings, but this will also give you their relative positions (after some calculation) because you have enough information from the field strength, the interval of time they spent at different potentials, and you sychronise them initially (which is ... more information). You don't need to know their actual positions, but they still have actual positions--each clock is in its own frame of reference, whether you have their actual positions or not.

 

[Farsight]

The clock rate is related to the potential at that altitude. The field strength relates to the gradient in potential and the difference in clock rates. See gravity works like this where I describe how you can obtain the Riemann-curvature "rubber sheet" depiction from clock rates. You take an equatorial slice through the Earth, and you place clocks at various locations in this slice. Clocks go slower when they're lower, so when you plot your clock rates, you get this:

GNUFDL image by Johnstone, see wikipedia

It really is that simple. Curved spacetime isn't curved space or curved time, it's just a curvature in your plot of clock rates. And those clocks are light clocks, so it's just a curvature in your plot of the speed of light.

 

[PhysBang]

It really is that simple. Curved spacetime isn't curved space or curved time, it's just a curvature in your plot of clock rates. And those clocks are light clocks, so it's just a curvature in your plot of the speed of light.

It is important to remember that Farsight is lying about all clocks being light clocks.

As Einstein points out, GR does not rely on regular clocks, anything can serve as a clock.

For this reason non-rigid reference-bodies are used which are as a whole not only moving in any way whatsoever, but which also suffer alterations in form ad lib. during their motion. Clocks, for which the law of motion is any kind, however irregular, serve for the definition of time. We have to imagine each of these clocks fixed at a point on the non-rigid reference-body. These clocks satisfy only the one condition, that the “readings” which are observed simultaneously on adjacent clocks (in space) differ from each other by an indefinitely small amount. This non-rigid reference-body, which might appropriately be termed a “reference-mollusk,” is in the main equivalent to a Gaussian four-dimensional co-ordinate system chosen arbitrarily. That which gives the “mollusk” a certain comprehensibleness as compared with the Gauss co-ordinate system is the (really unqualified) formal retention of the separate existence of the space co-ordinate. Every point on the mollusk is treated as a space-point, and every material point which is at rest relatively to it as at rest, so long as the mollusk is considered as reference-body. The general principle of relativity requires that all these mollusks can be used as reference-bodies with equal right and equal success in the formulation of the general laws of nature; the laws themselves must be quite independent of the choice of mollusk.

Farsight spends a lot of time trying to distract from tough questions or evidence counter to his pet theory. He is probably trying to distract himself.

 

[PhysBang]

What is the matter with you, arfa? Is there nothing which you and others will NOT complicate unnecessarily by invoking UNREAL THINGS maths/abstractions which are UNNECESSARY by the very setup of the two clocks one above the other in REAL SPACE and not in some esoteric maths-land world where you need 'frames' to tell you which clock is above the other IN THE SAME ROOM with you?

Here is the not-quite rational again.

You say that you know what a system of coordinates is, but then you demonstrate that you don't. You are talking about a room, a defined space, with defined locations for clocks at certain times identified by you. Sure, you are being vague, but you are still trying to specify spacetime locations in a rough way. This is because one cannot speak of physics without using some system of coordinates.

One does not need multiple reference frames to describe the change in clocks in that room. GR does not require this. Yet one can use clocks like this to produce evidence for GR. (Clifford Will's book, Was Einstein Right? is a great source for evidence for GR.)

Just because Undefined doesn't understand GR and can't figure out how people produce evidence for it does not mean that there is no evidence for it.

I don't need to know what 'frame' each clock is in. I only need to place them and see what transpires over the year as to respective cumulative counts in their registers.

If you want to present a physics , you will have to use some system of coordinates. This is an a priori requirement.

IF the counts DO differ, then we will KNOW BY GR PREDICTION that the clocks INDEED MUST have been in different altitudes in that same room.

No, one can give the clocks the same altitude and introduce a differential acceleration or gravitation field or some combination thereof.

There is no need to 'call' that differrent altitudes 'frames', because the GR EFFECTS are predicted and self-explanatory/consultable directly comparing the clock counts and inferring that GR must explain the differences IF there are any when compared the counts.

There is no need, but this doesn't preclude the ability to use different systems of coordinates, one associated with each clock.

Where does the fantasy world intrusion stop such that you can actually consult the SELF-EVIDENT REALITY once in a while like in THIS SPECIFIC SCENARIO?

It is your fantasy that one use of GR precludes all others.

 

[Farsight]

OK PhysBang, that's enough. You're on ignore.

All: PhysBang is not sincere, instead he's an ad-hominem naysayer troll. I started this thread, and thus I feel I have the right to ask you this: please do not feed the troll.

 

[PhysBang]

Yes, because I asked him for specific numbers and because I out-quoted him on Einstein, I'm on ignore. That's the quality of debate he offers.

 

[Farsight]

This message is hidden because PhysBang is on your ignore list.

Beat it, troll. Others here are having a sincere discussion.

 

[Grumpy]

Farsight

You are fast running out of non-cranks who you even listen to. The woo is getting concentrated and you are in the wrong forum to talk about woo. We have a cesspool for that.

Grumpy:crazy:

 

[Undefined]

But, the clocks are at different heights so they are at different potientials. The potentials determine the difference in clock rates; the field strength is known and it's trivial to measure the height of each clock.

You're missing the point that although the clocks are ticking at different rates, this is completely determined by the field strength and where each clock is. You get back the information from the clock readings, but this will also give you their relative positions (after some calculation) because you have enough information from the field strength, the interval of time they spent at different potentials, and you sychronise them initially (which is ... more information). You don't need to know their actual positions, but they still have actual positions--each clock is in its own frame of reference, whether you have their actual positions or not.

This has already been acknowledged as part of the setup and the reason for it. To just check that there IS a difference in light behavior/transit rate between the two differently GR-affected clocks. Period.

That's all that I wanted to establish between Farsight and those he was discussing with who attempted at first to pooh-pooh his point by trying to bring irrelevancies like co-ordinate frame considerations/analysis into it while ignoring that the setup itself in GR DOES already, and without further 'co-ordinate frame analysis/overlays', INDICATED DIRECTLY by comparison counts that the difference is REAL and LOCAL and must be explained EITHER by abstract math 'spacetime' length contraction/variation and clock time rate dilation....OR by real light speed slowing/variation and clock time rate dilation.

That is where the discussion is NOW at, and that was all I anted to get clear between them so they continued the discussion of the latter considerations/alternatives mentioned from 'the same page' that there was a difference in reality locally due to GR, and now the explanations/interpretations can proceed from that common ground understanding irrespective of any co-ordinates overlay insofar as to what the light clocks did in local GR real situations.

I will read the further discussion on the further aspects with interest. That's all I have to say for now, mate. I leave you and Farsight et al to it! Enjoy your discussions, arfa, everyone.

 

[Undefined]

Hi PhysBang.

Here is the not-quite rational again.

You say that you know what a system of coordinates is, but then you demonstrate that you don't. You are talking about a room, a defined space, with defined locations for clocks at certain times identified by you. Sure, you are being vague, but you are still trying to specify spacetime locations in a rough way. This is because one cannot speak of physics without using some system of coordinates.

One does not need multiple reference frames to describe the change in clocks in that room. GR does not require this. Yet one can use clocks like this to produce evidence for GR. (Clifford Will's book, Was Einstein Right? is a great source for evidence for GR.)

Just because Undefined doesn't understand GR and can't figure out how people produce evidence for it does not mean that there is no evidence for it.


If you want to present a physics , you will have to use some system of coordinates. This is an a priori requirement.

No, one can give the clocks the same altitude and introduce a differential acceleration or gravitation field or some combination thereof.


There is no need, but this doesn't preclude the ability to use different systems of coordinates, one associated with each clock.

It is your fantasy that one use of GR precludes all others.

No more time to spend on eliminating the bleeding obvious from the exchanges, or on responding to irrelevant cross-purpose commentary/misunderstandings/strawmen and personal jibes etc.

So, no further comment. Please read my reply to arfa on that, in post #435. Thanks. Good luck.

 

[arfa brane]

That's all that I wanted to establish between Farsight and those he was discussing with who attempted at first to pooh-pooh his point by trying to bring irrelevancies like co-ordinate frame considerations/analysis into it

Yes, I get it. You want to believe that abstractions = problems.

Unfortunately you can't use two clocks to show time dilation unless the clocks are at different potentials, which means you must have a way to determine that they are. There is no way around this because as I've said already, when you compare the clocks later, the difference is due to the difference in potentials, so the clocks reflect this: they are/were in a coordinate system that lets you use clocks to determine different potentials (or you could use their individual altitudes).

You cannot "do" anything meaningful in SR or GR sans coordinates. Einstein begins his 1905 paper with a precise way to define these and the distance light travels between them. I have to say that his paper would be a lot harder to understand without this introduction, and so would physics if it didn't use coordinate systems.

You cannot define a sphere mathematically so it doesn't have a way to define coordinates, it even gives you a choice. Likewise you can measure different potentials in reference to height "above" a surface, or by using clocks to measure time dilation effects, but you can't do either without some kind of coordinate system.

 

[paddoboy]

Let's get fair dinkum....
The theories of SR and GR are overwhelmingly supported and nothing comes close to describing reality then they do.
In realizing that we must also accept that the speed of light is constant...no if's or but's.
It's constant because it is massless [as far as we are able to tell] and therefor must always travel at "c"
If it slowed, we would by necessity need to apply mass to it.
Again, another storm in a tea cup from unsupported, un-reviewed, un-evidenced alternative theorists crap.
That is the nicest thing we are able to say regarding the myriad of silly alternative theories this section has to deal with.

Which then raises a more obvious point, why are they not in the "Alternative Theory"section?

 

[Undefined]

Hi arfa.

Yes, I get it. You want to believe that abstractions = problems.

Unfortunately you can't use two clocks to show time dilation unless the clocks are at different potentials, which means you must have a way to determine that they are. There is no way around this because as I've said already, when you compare the clocks later, the difference is due to the difference in potentials, so the clocks reflect this: they are/were in a coordinate system that lets you use clocks to determine different potentials (or you could use their individual altitudes).

You cannot "do" anything meaningful in SR or GR sans coordinates. Einstein begins his 1905 paper with a precise way to define these and the distance light travels between them. I have to say that his paper would be a lot harder to understand without this introduction, and so would physics if it didn't use coordinate systems.

You cannot define a sphere mathematically so it doesn't have a way to define coordinates, it even gives you a choice. Likewise you can measure different potentials in reference to height "above" a surface, or by using clocks to measure time dilation effects, but you can't do either without some kind of coordinate system.

Haven't you read and understood what I have told you more than once now? Abstraction = INCOMPLETE. That's the problem....incompleteness. OK?

How can pure maths/abstraction ever arrive at REALITY if it gets ever further away from it with every further abstract/math overlay interpretation? As Einstein himself bemoaned:

Since the mathematicians have invaded my theory, I do not understand it myself anymore.-----Einstein

Each setup/understanding that simplifies and directly consults the self-evident reality is a step back to reality approach/understanding instead of continuing into abstraction/math land which started to confuse even poor old Albert way back then already.

And have you ever heard of that simple 'instrument' called a "Plumb-Bob"? It is used by Builders to check the 'verticality' of some arrangement in the gravity well of Earth. They then know that any brick laid atop another is in a different frame, one above the other. That 'frame' consideration' is not relevant if the brick is seen as one above another along an altitudinal radial already established as vertical using the simple Plumb Bob.

No 'theory' or other analytical overlay necessary. The elements and the setup is sufficient unto the reality locally in that gravity well. Just as the clocks arranged in a lab room one above the other represents without any further unnecessary to-do.

That is the point of establishing local reality as self-evident rather than trying to make it UNREAL co-ordinate analysis construct DEPENDENT when it ISN'T in this scenario of the two clocks above one another in front of you. Use a Plumb Bob if you still can't tell "which way is up" in your lab in Earth's gravity well, mate.

 

[PhysBang]

This has already been acknowledged as part of the setup and the reason for it. To just check that there IS a difference in light behavior/transit rate between the two differently GR-affected clocks. Period.

That's all that I wanted to establish between Farsight and those he was discussing with who attempted at first to pooh-pooh his point by trying to bring irrelevancies like co-ordinate frame considerations/analysis into it while ignoring that the setup itself in GR DOES already, and without further 'co-ordinate frame analysis/overlays', INDICATED DIRECTLY by comparison counts that the difference is REAL and LOCAL and must be explained EITHER by abstract math 'spacetime' length contraction/variation and clock time rate dilation....OR by real light speed slowing/variation and clock time rate dilation.

And you can demonstrate how one can use a variable speed of light to get these differing clocks?