Black holes

[Farsight]

...If you're not interested in trying to explain your ideas, that's fine with me.

If you're not interested in conducting a sincere discussion, that's up to you.

And if they don't (fall down)? Which they won't, if we're in deep space.

Then we measure the speed of light in any direction.

Also, this doesn't help if we choose to conduct our experiments in free fall; how do you propose to determine horizontal if we're in a stable, circular orbit around the Earth (to take but one example)?

Look out of the window.

Not good, Farsight, not good.

You might like to look in a mirror, and tell your reflected self to go do some research.

I've done the research. That's why I can give references to back up my case.

For other readers: there are, already, known limits on the stability of any particular pulsar, and the optical clock Farsight mentioned is far more accurate/stable than any pulsar.

Other observers will verify that the pulsar rate doesn't change when you descend into a gravitational well. They will also verify that the clock rate of the clock you carry with you, does.

Further, Farsight has been rather sloppy here; he said exactly this (bold added): "However we are not so stupid as to use our parallel-mirror light clock to time the back-and-forth travel time. Or [...] We time it using the distant pulsar."

I haven't been at all sloppy. Let me spell out the point. I don't use bold often, but I think this time it's warranted: if you use your parallel-mirror light clock to measure the speed of light, then if light moves slower where you are as opposed to where you were, the light in your parallel-mirror light clock will move slower too. So your measurement of the speed of light will yield the same value at both locations. Give it up Dopa, you cannot conceal this simple point.

He didn't say which distant pulsar he intended/proposed to use, and if he meant to say something like 'a set, or array, of distant pulsars', he omitted to say how he'd use such an array as a clock. If you have a few hours to spare, you can peruse the (astrophysics) literature on this topic, and discover that it is very far from trivial how to set up such a thing. Curiously, the Wikipedia link Farsight gives as his source has, itself, two papers as sources, dated 1997 and 1984. This particular area in astrophysics (and physics, no doubt) is very active, and 1984 is like the distant past. Oh, and the current SI definition of the second dates to 1997. Perhaps Farsight is simply not conversant with the relevant literature?

He is. Just as readers of this thread are now conversant with your attempt to obscure the issue at hand.

 

[DeiRenDopa]

Let me know if I've skipped any posts.

Sure, will do.

Backtracking to the top of the page:

The second as-yet-unaddressed of Farsight's posts.

For my own purposes, I shall call "what Farsight says is the original GR that Farsight has read" Farsight's GR, FGR for short.

Point of clarification: do Wald and/or MTW contain the "what people say GR says"?

I'll let others answer that.

Not good Farsight, not good.

Here's what you wrote:

F: I've read the original GR, and the scientific evidence squares with it. However it doesn't square with what people say GR says.

It's your claim, that "the scientific evidence" doesn't square with "what people say GR says".

If you can't, or won't, clarify what you mean by "what people say GR says", then there is no objective way for anyone to evaluate your claim (other than, perhaps, yourself), right?

Kinda narrows down the scope of what we can have a meaningful discussion on, doesn't it?

The use of double quotes, as in ""artefacts of measurement"", by convention, means you are giving this term a meaning that is non-standard, one that is different from what a reader would normally infer.

The quotes were merely to highlight a phrase that some might find unfamiliar.

What do you intend this term to mean, in this context?

That a reference frame is not something you can actually measure, but is instead a convention used for measurement.

We most certainly need to get to a clear, mutual understanding of this!

It's quite clear enough. I can point up to the clear night sky and say "Look, that's a star. You cannot do the same for a reference frame.

Here's the context:

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me: For example, you seem to think that two clocks, separated by a foot or so in elevation are (must be?) in the same reference frame; i.e. that they can both measure 'local' time and that the 'local' is the same.

you: No. They're just two clocks at different elevations. They're in this room. Or if you prefer, they're in space near a planet. The things we call reference frames are "artefacts of measurement" that have no physical existence.
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I think we're going to have to go deeper here, in order to make sure the terms each of us uses have the same meaning (to each of us).

Let's take some, apparently simple, terms.

velocity: can you measure velocity? does it have physical existence? can you point up to the clear night sky and say Look, that's a star. It has a velocity of {x}?

gravitational potential: can you measure gravitational potential? does it have physical existence? can you point up to the clear night sky and say Look, that's a star. It has a gravitational potential of {x}?

temperature: can you measure temperature? does it have physical existence? can you point up to the clear night sky and say Look, that's a star. It has a temperature of {x}?

wavelength: can you measure wavelength? does it have physical existence? can you point up to the clear night sky and say Look, that's a star. It has a wavelength of {x}?

elevation: can you measure elevation? does it have physical existence? can you point up to the clear night sky and say Look, that's a star. It has an elevation of {x}?

I take a hard-headed approach: time is what a clock measures. The unit of time is the second, which is defined in the relevant SI standard. Two clocks are the same - for the purpose of measuring time - if they agree, when co-located. For me, the rest is philosophical fluff that we would all be better off without.

I take an even more hard-headed approach. I look inside the clock and I look at what it actually does measure.

How do you do that?

To be concrete, take a radioisotope clock. How do you "look inside" such a clock? Once you've looked inside one, how do you "look at what it actually does measure"?

But, if what clocks "actually do is clock up some form of regular motion", according to you, does that mean that you cannot - even in principle - build a clock based on the nuclear decay of an unstable isotope (to take one example)?

Stop wasting everybody's time Dopa. We all know about carbon dating.

That's twice now. I'm losing patience.

I wasn't aware that there are objective independently verifiable experimental and/or observational results about Hawking radiation. Can you cite some please?

No. There's no evidence for Hawking radiation, and yet it's bandied about as if it's settled science.

Evidence?

How does one measure the impedance of space? And is the impedance of space the same as vacuum impedance?

You measure the speed of light then apply c = √(1/ε₀μ₀) and Z₀ = √(μ₀/ε₀).

My algebra is rather weak; how can you derive Z₀ from c?

And is the impedance of space the same as vacuum impedance?

I thought it was photons which created charged particles via pair production, and that particle-antiparticle annihilation produces photons.

Would you like to read my paragraph again? Here it is:

Impedance is an electrical property of say a cable, but it applies to space too, which electromagnetic waves propagate through. It applies to alternating current rather than direct current, these both being associated with conduction current, which is the motion of charged particles. You can create such charged particles via pair production, and get the electromagnetic waves back again via annihilation. Those electromagnetic waves are displacement current rather than conduction current, and they wave. They're alternating.

OK, I re-read it.

I'll start more slowly, with just one, simple, question: what "electromagnetic waves" do you get by the annihilation of an electron and a positron?

What am I missing?

Honesty, it would seem. And you're boring everybody to death. Is that your intention?

No.

But let's do a simple experiment, shall we?

Would you be so kind, dear reader of this post (and JREF member), as to tell us all (by writing a post) if I am boring you to death? Thank you.

ETA: also, if you wouldn't mind, do you understand what Farsight has written (Impedance is an electrical property of say a cable, but it applies to space too, which electromagnetic waves propagate through. It applies to alternating current rather than direct current, these both being associated with conduction current, which is the motion of charged particles. You can create such charged particles via pair production, and get the electromagnetic waves back again via annihilation. Those electromagnetic waves are displacement current rather than conduction current, and they wave. They're alternating.)?

 

[Ziggurat]

But let's do a simple experiment, shall we?

Would you be so kind, dear reader of this post (and JREF member), as to tell us all (by writing a post) if I am boring you to death? Thank you.

ETA: also, if you wouldn't mind, do you understand what Farsight has written (Impedance is an electrical property of say a cable, but it applies to space too, which electromagnetic waves propagate through. It applies to alternating current rather than direct current, these both being associated with conduction current, which is the motion of charged particles. You can create such charged particles via pair production, and get the electromagnetic waves back again via annihilation. Those electromagnetic waves are displacement current rather than conduction current, and they wave. They're alternating.)?

For me, the answer to both questions is no.

 

[DeiRenDopa]

This is what I'm asking you: what scientific evidence? I have a bunch of data from well-known gravity experiments. I have bunch of well-known mainstream-GR predictions for those experiments. I have a bunch of statistical data analysis saying that the experiments agree with the predictions. That's "scientific evidence"---the behavior of nature agrees with actual GR calculations performed by normal MTW-trained physicists.

I'm quite puzzled about this too.

So far as I can tell, the only "scientific evidence" (hard or otherwise) Farsight has provided (so far anyway) is various experimental and observational results which are fully consistent with GR*.

Can anyone reading this honestly say they know what "scientific evidence" Farsight is referring to?

* they may also be consistent with FGR, but as only Farsight knows what that is, and hasn't explained it in a way that anyone else participating in this thread understands (so it seems), that's not very helpful.

 

[Hellbound]

To answer the questions:
No, Dei, you aren't boring.

I understand what he's saying about impedance, I think, it's worded poorly and partially incorrect (and I'm just looking at the quote, not the original in context). However, I don't see how it's fundamentally different from the much shorter and clearer post of yours that he was "correcting". Now, I am not a physicist, but have had some training in electronics and have a good layman's grasp of physics...so take my opinions for what they're worth

To Farsight:

Don't take this the wrong way, but the boring part is your repeated assertions without anything additional in the way of evidence or even explanation. You seem to take any request for aditional information as some sort of insult or as set up for a trap. People here are trying to udnerstand what you're saying, but you haven't really made it clear at all. You keep saying the same things repeatedly without ever clarifying questions. I believe it would improve all sides of the coversation if you could slow down, put aside the animosity for a bit, and try to answer the questions...nto with generalities but with specifics. Science isn't a shotgun, it's a sniper rifle. Precision counts.

 

[ben m]

He is. Just as readers of this thread are now conversant with your attempt to obscure the issue at hand.

Farsight, that's probably the 10th time you've pulled this nonsense. "Everyone sees you're wrong". "You've got no argument, and everyone knows it". "I have a psychic link to all of the lurkers on this thread, and there are 17 people laughing at you RIGHT NOW." I don't know how long you've been leaning on this rhetorical trick, but please retire it right now.

 

[DeiRenDopa]

All points noted.

That's strange. You start with "No", but end up agreeing with me! I can't "follow the reasoning [you] offer" if I am unsure of the meaning of key terms you use in that reasoning.

It's not strange at all. You said those who seek to understand you need to be confident your understanding of key terms you use is the same as their own, right? I said No. You need to be confident that the scientific evidence I present is correct, and then you should be confident in your own ability to think for yourself and follow the reasoning I offer. Key terms aren't the issue here, the scientific evidence is.

Thanks for the clarification.

Clearly we need to spend more time on this "scientific evidence".

There are several examples of this already, in this thread alone, for just me. For example, your notions of what clocks are, and how the microwave cavity works in the NIST cesium fountain clock. Others have pointed out that your use of 'speed of light' is, at times, inconsistent (and that's just one example). You apply classical electromagnetism to quantum phenomena (e.g. pair production and annihilation). And so on.

I apply experimental physics. You are raising spurious issues and presenting a straw-man argument instead of addressing the scientific evidence offered by that experimental physics.

There's that "scientific evidence offered by that experimental physics" again.

Yep, more time on this is needed.

May I take it that the reverse is also acceptable to you? If I find our exchanges turning into evasion and distraction on your part, forget it?

Please feel free to do so.

Thanks.

I'm glad we're on the same page on this.

You're saying nothing. Address the scientific evidence.

Sure, I'll be very happy to do just that.

Let's start with what it actually is, shall we?

Please be patient.

The only "scientific evidence offered by that experimental physics" that you've offered, so far*, is one optical clock 'running slower' than another, the two clocks being separated by ~a foot in elevation.

As far as I know, this "scientific evidence offered by that experimental physics" is consistent with GR. If so, then the breakdown in communication is, pace you, that I cannot "follow the reasoning [you] offer".

Of course, it may well be that this "scientific evidence offered by that experimental physics" is inconsistent with FGR, but since I don't know what FGR is (and I suspect few, if any, others reading this thread do either), we're back to a failure to follow the reasoning you offer (and not, to repeat, the scientific evidence).

* I could be quite mistaken, and you have, in fact, offered more; if you, please be kind enough to repeat it and/or point to your posts, in this thread, containing it.

 

[Farsight]

OK, how about this then?

F: The optical clock uses aluminium rather than caesium, and a UV frequency rather than a microwave frequency, but it works along the same lines, and employs electromagnetic phenomena. When electrons move by doing a spin-flip, they emit electromagnetic waves, which move away more slowly quickly from an optical clock at an elevation of a foot (or so) above an otherwise identical optical clock.

That's better.

 

[DeiRenDopa]

Substantive points only ...

And if they don't (fall down)? Which they won't, if we're in deep space.

Then we measure the speed of light in any direction.

That's what I expected you to say.

Why didn't you just say so the first time? (that's a rhetorical question)

Also, this doesn't help if we choose to conduct our experiments in free fall; how do you propose to determine horizontal if we're in a stable, circular orbit around the Earth (to take but one example)?

Look out of the window.

Sorry, that doesn't answer the question.

Would you care to try again?

Not good, Farsight, not good.

You might like to look in a mirror, and tell your reflected self to go do some research.

I've done the research. That's why I can give references to back up my case.

Please do so.

For other readers: there are, already, known limits on the stability of any particular pulsar, and the optical clock Farsight mentioned is far more accurate/stable than any pulsar.

Other observers will verify that the pulsar rate doesn't change when you descend into a gravitational well. They will also verify that the clock rate of the clock you carry with you, does.

I think, in your internet posting, you'll have come across the phrase "move the goalposts", right?

Well, here's a particularly spectacular example of just that.

To see why, we need to go back to how we got started on this. Here's the set of exchanges (if anyone really wants them, I can add links):

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This began with me proposing some experiments, all of which have to do with measuring things locally, like depth, pressure, g, altitude/elevation, and time.

me: Oh, one more thing we need to agree on: how to measure the speed of light.

Can you please describe how we can do this, using devices/equipment/techniques/etc which incorporate - at whatever critical point necessary - the definitions of the second and the meter?

Farsight: We measure the speed of light with light and mirrors, like Fizeau did. We already know something about relativity, so we constrain our measurements to horizontal measurements to avoid radial length contraction and keep our experiment simple. However we are not so stupid as to use our parallel-mirror light clock to time the back-and-forth travel time. Or our atomic clock, because that employs the electromagnetic hyperfine transition and microwaves. Or the optical clock which employs UV light. Or the quartz wristwatch, because that's electromagnetic like light. Or the mechanical clock, because that's made of electrons and protons etc, which have an electromagnetic nature. We time it using the distant pulsar.

me: As far as I know, Fizeau used several different experimental setups, each with light and mirrors.

And we need to be pretty specific, I think, so would you mind spelling out the actual setup you recommend, in more detail?

OK, but as we will be doing our experiments in many different environments, including in deep space, we need a way to establish what "horizontal" is; how do you recommend we do that?

We may have a problem here Houston.

Or not; can you explain how we "time it [the back-and-forth travel time, in some Fizeau-like set-up] using the distant pulsar"?

Farsight: Yes I would, stop wasting my time. Everybody knows the setup, see English Wikipedia.

You note which way things fall down, then you take an orthogonal direction.

Are you for real? Go do some research.
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So, the whole point of my question was to try to find a way - that Farsight and I could agree - to measure the local speed of light.

The entire research program I've outlined, so far, is aimed at local measurements, and at understanding how they can be modeled.

What Farsight has done, with this last post, is move the goalposts, to examine things beyond the scope of the clearly stated program. For sure, those things are quite interesting, and well worth examining. But let's not get ahead of ourselves, shall we?

Further, Farsight has been rather sloppy here; he said exactly this (bold added): "However we are not so stupid as to use our parallel-mirror light clock to time the back-and-forth travel time. Or [...] We time it using the distant pulsar."

I haven't been at all sloppy. Let me spell out the point. I don't use bold often, but I think this time it's warranted: if you use your parallel-mirror light clock to measure the speed of light, then if light moves slower where you are as opposed to where you were, the light in your parallel-mirror light clock will move slower too. So your measurement of the speed of light will yield the same value at both locations. Give it up Dopa, you cannot conceal this simple point.

Right. It will.

So, back to my question: how do you use a distant pulsar to measure the local speed of light?

Got it now?

He didn't say which distant pulsar he intended/proposed to use, and if he meant to say something like 'a set, or array, of distant pulsars', he omitted to say how he'd use such an array as a clock. If you have a few hours to spare, you can peruse the (astrophysics) literature on this topic, and discover that it is very far from trivial how to set up such a thing. Curiously, the Wikipedia link Farsight gives as his source has, itself, two papers as sources, dated 1997 and 1984. This particular area in astrophysics (and physics, no doubt) is very active, and 1984 is like the distant past. Oh, and the current SI definition of the second dates to 1997. Perhaps Farsight is simply not conversant with the relevant literature?

He is. Just as readers of this thread are now conversant with your attempt to obscure the issue at hand.

Let's see, shall we?

Dear readers of this thread, are you "now conversant with [my] attempt to obscure the issue at hand"?

 

[Farsight]

If I accelerate, your motion becomes curved. If motion is truly relative, then this curvature is real in my reference frame. Yes, it's reference-frame dependent, but so is your velocity. That doesn't make it illusory.

I'll presume you're referring to our orthogonal relative motion, presumably in deep featureless space where we can detect no discernible gravitational field. Our relative motion is no illusion, but if you accelerate, you accelerate. You can feel it. You can stop accelerating and start accelerating again, and work out that your foot on the gas pedal is what's causing my motion to appear curved to you. Whilst I can't be sure whether I'm moving or not in any absolute sense, I can be sure that I'm not accelerating, because I'm floating around in my cabin, so I know my motion isn't curved in any real sense. I can't feel that acceleration, you can, and when we confer on the radio we can both agree that it's you who is changing your state of motion. We agree on what's real, such as your flaring booster. And we agree that the on-off curvature of my motion, is not.

I will receive your admission of error with sympathy. Don't worry about it, we all make a mistake from time to time, and we are each of us a better man for admitting to it.

And don't come back with that whole "reference frames aren't real" nonsense. They are as real as motion is. They are what motion is relative to. You cannot even define motion without a reference frame, even if you only want to define that frame implicitly.

You're real, I'm real, our rockets are real, space is real, the light we see each other with is real, and our relative motion is real, as we will discover emphatically should we collide. You use real things to define the thing you call a reference frame, but do not mistake it for something it is not.

 

[Ziggurat]

I'll presume you're referring to our orthogonal relative motion, presumably in deep featureless space where we can detect no discernible gravitational field. Our relative motion is no illusion, but if you accelerate, you accelerate. You can feel it. You can stop accelerating and start accelerating again, and work out that your foot on the gas pedal is what's causing my motion to appear curved to you. Whilst I can't be sure whether I'm moving or not in any absolute sense, I can be sure that I'm not accelerating, because I'm floating around in my cabin, so I know my motion isn't curved in any real sense. I can't feel that acceleration, you can, and when we confer on the radio we can both agree that it's you who is changing your state of motion. We agree on what's real, such as your flaring booster. And we agree that the on-off curvature of my motion, is not.

I agree that my reference frame is not the same as your reference frame, because my reference frame is not inertial. But I have no reason to conclude that the curvature of your trajectory is not real. It is real, in my reference frame. There is no experiment I can perform which contradicts this.

I will receive your admission of error with sympathy.

No, I don't think you will.

 

[Farsight]

Brian is right, you are wrong. Current definitions of the SI units
"The second is the duration of 9 192 631 770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the cesium 133 atom."

I know more than you think, and I've thought this through. Put yourself in space free of any discernible gravitational field, but let's make it just a little more realistic. It's dark in visible wavelengths, maybe dusty. You can't see any nearby stars, but you can detect the 21cm hydrogen line. This electromagnetic radiation "is at the precise frequency of 1420.40575177 MHz". You detect it, and find it to be isotropic. You know that it's coming at you at the speed of light, and that there is a direct relationship between wavelength and frequency. And you also know that frequency is measured in Hertz, which is cycles per second. You know that this tells you how many wavelengths pass you by in a second. So if your master clock suffers some breakdown, you know that you can recalibrate it by counting the hydrogen-line microwaves passing you by. When you get to 1,420,405,751.77, that's a second. It's very simple. You defined your second using the motion of light. That's what the NIST clock does.

 

[Ziggurat]

I know more than you think, and I've thought this through.

No, you haven't. And there's nothing to think through: it's right there in the definition. The definition of a second has absolutely nothing to do with the speed of light.

Put yourself in space free of any discernible gravitational field, but let's make it just a little more realistic. It's dark in visible wavelengths, maybe dusty. You can't see any nearby stars, but you can detect the 21cm hydrogen line. This electromagnetic radiation "is at the precise frequency of 1420.40575177 MHz". You detect it, and find it to be isotropic. You know that it's coming at you at the speed of light, and that there is a direct relationship between wavelength and frequency. And you also know that frequency is measured in Hertz, which is cycles per second. You know that this tells you how many wavelengths pass you by in a second. So if your master clock suffers some breakdown, you know that you can recalibrate it by counting the hydrogen-line microwaves passing you by. When you get to 1,420,405,751.77, that's a second. It's very simple. You defined your second using the motion of light. That's what the NIST clock does.

One is able to measure a length and convert it to a time by using c. Nobody disputes that. But that's not the question, and that's not the claim. The claim is about how the second is defined. And it is defined without reference to c. The meter is defined in reference to c, NOT the second. After these standards have been established, we can use them to work backwards if needed, but they're defined in one direction, and they are so defined for a damned good reason.

Hell, even within your own scenario, your described procedure doesn't even use c.

 

[Farsight]

Wrong about what? What scientific evidence?

That the speed of light varies, remember?

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And that light can't get out of a black hole even when it's pointing straight up? When it doesn't slow down, and doesn't fall back, and doesn't curve round? I'm sure you're fine with that. There's some monstrous massive thing in the middle of our galaxy, it's very very small, and it isn't shining. And surely you don't adhere to that sky-is-falling in space-sucking waterfall nonsense? Please?

The only thing I can figure out is that you think any coordinate transforms which eliminate the coordinate singularity of the Schwarzchild coordinates is wrong. But since the only evidence you've presented (what a distant observer will see) actually agrees with the predictions using other coordinates, that hardly proves them wrong. So your scientific evidence hasn't trumped anything.

I've got hard scientific evidence that the speed of light varies. Not just the coordinate speed of light, the speed of light. And my Uncle Albert backs me up on that. That means it isn't a coordinate singularity, it's a place where the speed of light is zero. It isn't something you can transform away. Put an observer at that place and he doesn't see things normally "in his proper time" as if nothing has happened. Nothing happens. He doesn't see anything. Not ever.

Right, it's been a fun day guys, but I have to go. Think about what I've told you, ask around, mull it over, and most importantly of all, think for yourself. That hard scientific evidence is horribly obvious once you see it.

 

[D'rok]

Lurking in this thread, I have learned that "hard scientific evidence" means "Farsight's iconoclastic intuitions and just-so qualitative narratives".

I've also learned that Farsight is the only one who has managed to "think it through". Shame on all of you actual scientists for labouring away in ignorance, relying on regurgitation, quantification and rote learning.

 

[Ziggurat]

That the speed of light varies, remember?

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|--------------------|

Again, this conclusion only holds for a particular choice of reference frames. Change the reference frame, and a lot of critical details about your scenario change too, including when events happen and the distance between events.

And that light can't get out of a black hole even when it's pointing straight up?

You never actually defined "up". But never mind, none of that actually matters here. Your mistake is even more fundamental than that. This isn't evidence that you are right and anyone else is wrong, because EVERYONE agrees on that point. Examine a black hole under any coordinate system (uncluding Kruskal coordinates), and that will remain true. So nothing about this statement indicates that Kruskal coordinates are invalid.

There's some monstrous massive thing in the middle of our galaxy, it's very very small, and it isn't shining. And surely you don't adhere to that sky-is-falling in space-sucking waterfall nonsense? Please?

Why not? There are no predictions that such a coordinate system makes which are in conflict with the observations you have suggested. Your objection has been purely aesthetic.

I've got hard scientific evidence that the speed of light varies. Not just the coordinate speed of light, the speed of light. And my Uncle Albert backs me up on that. That means it isn't a coordinate singularity, it's a place where the speed of light is zero.

And yet, every single actual measurement you have referred to will produce identical results if we are correct. You have not once pointed to an experiment where my prediction will differ from yours.

It isn't something you can transform away. Put an observer at that place and he doesn't see things normally "in his proper time" as if nothing has happened. Nothing happens. He doesn't see anything. Not ever.

How would you know?

Oh, that's right, because of the signal you receive from him. But that's exactly the same signal you should expect if we're right. So how can that prove us wrong when your experimental results (well, thought experiment results) agree with our prediction?

You've got a massive elementary logic failure here, Farsight.

 

[DeiRenDopa]

But let's do a simple experiment, shall we?

Would you be so kind, dear reader of this post (and JREF member), as to tell us all (by writing a post) if I am boring you to death? Thank you.

ETA: also, if you wouldn't mind, do you understand what Farsight has written (Impedance is an electrical property of say a cable, but it applies to space too, which electromagnetic waves propagate through. It applies to alternating current rather than direct current, these both being associated with conduction current, which is the motion of charged particles. You can create such charged particles via pair production, and get the electromagnetic waves back again via annihilation. Those electromagnetic waves are displacement current rather than conduction current, and they wave. They're alternating.)?

For me, the answer to both questions is no.

Thanks.

To answer the questions:
No, Dei, you aren't boring.

I understand what he's saying about impedance, I think, it's worded poorly and partially incorrect (and I'm just looking at the quote, not the original in context). However, I don't see how it's fundamentally different from the much shorter and clearer post of yours that he was "correcting". Now, I am not a physicist, but have had some training in electronics and have a good layman's grasp of physics...so take my opinions for what they're worth

Thanks.

To Farsight:

Don't take this the wrong way, but the boring part is your repeated assertions without anything additional in the way of evidence or even explanation. You seem to take any request for aditional information as some sort of insult or as set up for a trap. People here are trying to udnerstand what you're saying, but you haven't really made it clear at all. You keep saying the same things repeatedly without ever clarifying questions. I believe it would improve all sides of the coversation if you could slow down, put aside the animosity for a bit, and try to answer the questions...nto with generalities but with specifics. Science isn't a shotgun, it's a sniper rifle. Precision counts.

Well said.

 

[DeiRenDopa]

Address the scientific evidence.

Sure, I'll be very happy to do just that.

Let's start with what it actually is, shall we?

Please be patient.

The only "scientific evidence offered by that experimental physics" that you've offered, so far*, is one optical clock 'running slower' than another, the two clocks being separated by ~a foot in elevation.

As far as I know, this "scientific evidence offered by that experimental physics" is consistent with GR. If so, then the breakdown in communication is, pace you, that I cannot "follow the reasoning [you] offer".

Of course, it may well be that this "scientific evidence offered by that experimental physics" is inconsistent with FGR, but since I don't know what FGR is (and I suspect few, if any, others reading this thread do either), we're back to a failure to follow the reasoning you offer (and not, to repeat, the scientific evidence).

* I could be quite mistaken, and you have, in fact, offered more; if you, please be kind enough to repeat it and/or point to your posts, in this thread, containing it.

Wrong about what? What scientific evidence?

That the speed of light varies, remember?

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Now Farsight did not reply to me, with this "That the speed of light varies, remember?"

However this - or something very much like it - has been posted, by Farsight, in this thread, several times.

So it may be reasonable to conclude that this is what he means by the "scientific evidence offered by that experimental physics".

Now from other posts by Farsight, we know that he agrees that the speed of light measured locally - using the sort of clock used by NIST to define the unit of time (the second) and the sort of device used by NIST to define the unit of length (the meter) - is the same. In other words, the speed of light does not vary, locally.

We do not know - yet - if Farsight can describe a setup by which the local speed of light can be seen to vary, using a 'pulsar clock', for example.

We also know that Farsight has said that two otherwise identical clocks, not co-located, may not tick at the same rate (some caution is required here; the precise phrasing of this idea may matter a great deal). Also that with one particular kind of clock such a lack of synchronization (same care-with-words caveat) may be seen over a vertical distance, near the Earth's surface, of ~0.3 meters.

It would appear that, to Farsight, this sort of non-local out-of-synch behavior of clocks is hard scientific evidence that "the speed of light varies".

My attempts to explore these assertions, claims, and ideas posted by Farsight have not, as yet, been very successful.

And I think - reading through this thread - no one else has been successful (at understanding Farsight's claims, etc).

Out of curiosity, would any reader care to suggest how the relative rates of otherwise identical clocks might vary, with elevation? For simplicity, assume the Earth is an isolated, non-rotating, isodense, solid, perfect sphere, of radius 5,000 km, and that 'elevation' means 'distance, in meters - as measured by devices keyed to the SI definition of the unit of distance - from the geometric center of the Earth, minus 5,000 km'.

 

[Ziggurat]

Out of curiosity, would any reader care to suggest how the relative rates of otherwise identical clocks might vary, with elevation?

I have an explanation that is in perfect accord with Farsight's observations. The speed of light isn't changing, and time isn't slowing down: rather, the meter is just getting longer and longer the closer we get to the event horizon. This perfectly explains everything: it takes an infinite amount of time to reach the event horizon because the event horizon is infinitely far away, and light gets infinitely red shifted because the original wavelength becomes infinitely larger since the meter keeps expanding.

Let's see if he can wrap his head around that one.

 

[W.D.Clinger]

Are you serious??

Farsight appears to believe he's being serious.

Would you be so kind, dear reader of this post (and JREF member), as to tell us all (by writing a post) if I am boring you to death? Thank you.

No, you are not boring me.

ETA: also, if you wouldn't mind, do you understand what Farsight has written (Impedance is an electrical property of say a cable, but it applies to space too, which electromagnetic waves propagate through. It applies to alternating current rather than direct current, these both being associated with conduction current, which is the motion of charged particles. You can create such charged particles via pair production, and get the electromagnetic waves back again via annihilation. Those electromagnetic waves are displacement current rather than conduction current, and they wave. They're alternating.)?

I recognize most of the words, and some of the phrases, but I'm pretty sure I do not understand the highlighted stuff.

I'm not a physicist, of course, and my algebra is no better than yours.

So far as I can tell, the only "scientific evidence" (hard or otherwise) Farsight has provided (so far anyway) is various experimental and observational results which are fully consistent with GR*.

Can anyone reading this honestly say they know what "scientific evidence" Farsight is referring to?

No. So far as I can recall, Farsight has alluded to only two kinds of scientific evidence:

• Evidence that is perfectly consistent with mainstream interpretations of general relativity.
• Evidence that doesn't actually exist except as Farsight's gedanken results of Farsight's gedanken experiments.

Dear readers of this thread, are you "now conversant with [my] attempt to obscure the issue at hand"?

No. If you want to obscure the issue at hand, you'll have to try much harder.

Out of curiosity, would any reader care to suggest how the relative rates of otherwise identical clocks might vary, with elevation? For simplicity, assume the Earth is an isolated, non-rotating, isodense, solid, perfect sphere, of radius 5,000 km, and that 'elevation' means 'distance, in meters - as measured by devices keyed to the SI definition of the unit of distance - from the geometric center of the Earth, minus 5,000 km'.

To a first approximation, I might guess that, for two clocks located just one foot apart, the earth's rotation has negligible effect. With that assumption, I'd look for a spherically symmetric solution to Einstein's field equations around a massive object. (Without that assumption, I'd use the Kerr solution.) I might then select a chart that's as flat as possible at some point on the world line of a gedanken observer, and I might use those coordinates with the transformed Schwarzschild metric to calculate the behavior of the clocks as observed by that observer.

So far as I know, however, the world line of that gedanken observer has not yet been described, so I guess I'm stuck until someone invents a mathematical theory that could tell us what would be observed along any world line whatsoever...