Tutorial: Relativity of simultaneity

[Prosoothus]

funkstar,

Suppose I say it is, prove it isn't. Ever hear the very true "Absence of Evidence is not Evidence of Absence"?

Yes. From creationists.

Ha. That was a good one.

Those atomic clock are faulty, then?

Let me just say if that if the omnidirectional speed of light, on the surface of the Earth, is equal to c ONLY relative to the Earth (for example if the Earth drags space around, or if the gravitational field of the Earth is the aether), then the average speed of light in an object that is moving close to, and relative to, the Earth would slow down. The slowing down of light in that object would cause the reactions in that object to slow down as well, giving the impression to a relativist that time is dilating. So the fact that atomic clocks that were moving relative to the Earth have been shown to tick slower can be used as proof that relativity is valid, or proof that relativity is invalid, depending on what you believe.

 

[superluminal]

Prosoothus,

So what you are saying is that 'c' (in a vacuum) may be measured to be different if it was measured well outside of a gravitational field?

Well, in the 1600's a guy named Roemer measured the speed of light by observing the changing times of the eclipses of Jupiters moons. He got a figure of 185,000 miles per second. Pretty close to the 186,282 mi/s we have today.

 

[2inquisitive]

Remember the cesium clocks in orbit? The atomic clocks at sealevel and comparative
atomic clocks on a mountaintop? The higher up in a gravitational field, the faster the
clocks tick. I saw on a physics website that light clocks and atomic clocks will react
identically to gravitational fields, a question I once asked Yuriy to he also responded
yes. Remember the definition of a meter? A meter is DEFINED as the distance light
will travel in 1/299,792,458 second. If the tick between seconds shorten (fast clock)
relative to a clock on Earth, then one of two things must happen: (1) Light is travelling
at a higher speed relative to the Earth frame, or (2) A meter must be measured SHORTER relative to a meter on Earth. Shorter because if light were a constant compared to both frames, it would have less time (fast tick) to travel a certain distance in the space frame. That shortening of the meter would have to occur in
ITS OWN FRAME, not just viewed from another frame of reference. If the speed of light increases with lower gravity,
the effect could never be measured in that frame, light would still travel a meter
in that faster tick. That's why I have always said the speed of light was relative to
the gravitational field, quantum vacuum, etc. that it is in. Within that specific frame
of reference, an observer would always measure the speed of light to be 'c', but relative to another observer in a different gravitational field, it would be different. Don't
forget, these differences in tick rates are very small and any light speed changes would also be very small.

 

[Neddy Bate]

If the tick between seconds shorten (fast clock) relative to a clock on Earth, then one of two things must happen: (1) Light is travelling at a higher speed relative to the Earth frame, or (2) A meter must be measured SHORTER relative to a meter on Earth. Shorter because if light were a constant compared to both frames, it would have less time (fast tick) to travel a certain distance in the space frame. That shortening of the meter would have to occur in ITS OWN FRAME, not just viewed from another frame of reference.

Hello 2inquisitive,

According to SRT, I believe that the definition of a meter can be universally defined by the distance light travels in any inertial reference frame. My very slight understanding of GRT makes me think that a meter can also be defined in non-inertial reference frames if measured in a direction parallel to the direction of the force of gravity (or pseudo-gravity.)

Let us now decide between the two opposing results which you correctly deduced:
(1) that c is not constant when measured across different areas of gravitational potential energy in a field of gravity - OR -
(2) that the meter would have to change in its own reference frame

I think we would agree that meters cannot change length in their own frame of reference -- that this would be a physical impossibility. The answer must be (1), which is consistent with relativity which only claims that c is constant to observers in their own reference frame.

I believe your paradox goes away when you consider what would happen if a ray of light from the fast clock travelled over to the slow clock. The velocity would lower accordingly as it passed into the area of lower gravitational potential energy. Thus it would still be c.

 

[MacM]

Explain how it is prohibited.

If you don't know that then you certainly lack any knowledge to be making the following comments.

Really? You do know that the Big Bang theory entails that it started, literally, right here? And that it also, literally, started everywhere else

So, no, that wouldn't be a reasonable answer.

Yes really and of course I know that.

Yes. From creationists.

Funny. The only thing that could piss me off more than a smart mouthed SRT'ist is being called a creationist.

I dispise all religons.

Also, in this case we have an astonishing body of evidence against it.

Well I know you think you do but you are far to new here to know the flaws in what you think is evidence.

So it's all brainwashing, instead. Fascinating.

I suppose you can lable anything anything but whatever lable you want to put on it there is indeed a bias in the scientific community. Are there crackpots, certainly but there are also many highly trained scientist that have run experiments which contridict the general concept of relativity as advocated. Without fail each that had the courage to raise such issues became summarily defrocked and basically black balled and labled.

In the context of the original thought experiment what I'm saying is obviously correct. As for reality, I'm sure you're aware of the evidence for the invariance principle. If not, there's a small list here

One of two basic postulates of course. But it is being misapplied.

My justification is the invariance principle. It precludes an absolute space and time - in fact, the very purpose of this thought experiment is to show that such a thing is an illusion based on nothing more than the invariance principle.

Oh I see. HeHe. You do have some learning yet to do.

Then you must have missed this gem:
“ Originally Posted by geistkiesel

In the experiment in the figure all time measurements are wrt the moving clocks.
”

Which flatly contradicts the invariance principle.

How so? Careful I am baiting a trap.

It explains specifically where he is wrong and why.

Be more specific.

Did you not see that I granted him an extra frame if he wanted it?

You granted him an extra frame. How nice. When this waltz is over then perhaps we can begin to take apart your view piece by piece.

Because if the rod clocks read different times, then light has taken different rod time to cover the same distance in the rod frame. This directly contradicts the assumption of constancy of light speed in all frames! Is it somehow hard to grasp why? It's very basic, yet it seems to me that we're flogging the horse, here...

I am sure it does. But I think as you mature here you will find there is more to all this than a bunch of dummies talking around a campfire.

As viewed from the rod frame, yes. As viewed from the embankment frame, no. Did you read the original post at all? Do you even understand what the invariance principle states?

Get nasty and I'll get nasty back.

Which is why asking us to prove relativistic effects without the basic assumptions that make us able to present them in a consistent manner is... well... stupid. James R's thought experiment assumes the invariance principle. geistkiesel claimes to refute his analysis based on an assumption of absolute space and time. Do you (both you and geistkiesel) see why this doesn't work?

I have made it clear that I agree with some things but not all things Geistkiesel has said. And it is vice versa I am sure. We are not a coherent groupd rallied around the flag as are SRT'ists.

Hint: The invariance principle and absolute space and time are incompatible.

Good. Now add this to your repretoire. "SRT reciprocity and physical reality and data are incompatible".

Both in the direct sense that no anisotropy of light speed has ever been found, and that prediction based on theories that incorporate the invariance principle are far closer to observation than those not incorporating them. For instance, gravitational bending of radio waves by the sun matches incredibly well with GR's predictions.

You would mean of course like the delay in radar signals passing by the sun or planets also supports the view of non-invariance of light in a gravity field, equally well as the affect being caused by GR.

Nice. You want to go back to a Newtonian universe, so we're reactionary.

Funny, I haven't mentioned Newton and NO I do not want to go back to Newton, nor do I plan to be stuck in this rut you call Einstien's Relativity.

The universe has clearly shown us relavistic affects but it has also shown us that Einstien has it wrong. I favor moving on and either trashing Einstien or making signifigant ammendment upgrades based on actual data and not mis-interpretations of data.

Those atomic clock are faulty, then?

Well. This certainly clarifies your view. You seem to have no idea what reciprocity is. Go find out and come back when you can present ONE case where SRTheory has ever been recorded as advocated. I am not talking about simple gamma calculatons, I am talking about SRTclaims.

Do that then you have something to rant and rave about. Until then nothing you have said above saves SRT.

 

[James R]

Are there crackpots, certainly but there are also many highly trained scientist that have run experiments which contridict the general concept of relativity as advocated.

Which scientists? References, please.

 

[MacM]

Which scientists? References, please.

Never mind we have been through this before. I posted several, such as one that helped develope GPS and was highly respected, even world renouned. He (based on his experience with GPS) crossed over and joined the dissadents and you called him a quack. Merely because he chooses to speak out as I have as to what GPS shows us.

 

[James R]

What experiments did this quack perform?

 

[2inquisitive]

I'm pretty sure MacM is speaking of Ron Hatch. Here is a little background on him.
He might be considered a 'quack', but his credentials are impressive.
==========================================

About The Author of Ether Gauge Physics
Ronald R. Hatch


Ron has served in several positions for the Institute of Navigation (ION) and in June 2001 was elected President of ION. (This is the organization that conducts the premier conference relating to the Global Positioning System (GPS), a conference typically drawing over 2,000 people to the sessions and exhibits.)

He has been working with navigation and communications using satellites since 1962, when, still in college, he worked for the U.S. Science Exhibit at the Seattle World's Fair demonstrating the Doppler effect on the signals received from the TRANSIT satellites of the Navy Navigation Satellite System. This system was developed by John's Hopkins Applied Physics Laboratory, where Ron worked developing navigation algorithms immediately following college.

Throughout his 30-year career in satellite navigation systems with companies such as Boeing and Magnavox, Ron has been noted for his innovative algorithm design for Satellite Navigation Systems. He has consulted for a number of companies and government agencies developing dual-frequency carrier-phase algorithms for landing aircraft, multipath mitigation techniques, carrier phase measurements for real time differential navigation at the centimeter level, algorithms and specifications for Local Area Augmentation System (LAAS), high-performance GPS and communication receivers, and Kinematic DGPS.

In 1994, he received the highest honor of the ION's Satellite Division, the Johannes Kepler Award for "Sustained and significant contributions to satellite navigation" -- only the fourth recipient of this prestigious award."
http://www.egtphysics.net/Author/Ronh.htm

 

[geistkiesel]

McM anad Funkstar, I jmped in here as I have when I saw my handle mentioned, therefore I am responding to both of you motre particularly to Funkstrar.

Oh I see. HeHe. You do have some learning yet to do.

“ Then you must have missed this gem:

“ Originally Posted by geistkiesel

In the experiment in the figure all time measurements are wrt the moving clocks.

”

Which flatly contradicts the invariance principle. ”

How so? Careful I am baiting a trap.

“ It explains specifically where he is wrong and why. ”

Be more specific

.

“ Did you not see that I granted him an extra frame if he wanted it? ”

You granted him an extra frame. How nice. When this waltz is over then perhaps we can begin to take apart your view piece by piece.

Because if the rod clocks read different times, then light has taken different rod time to cover the same distance in the rod frame. This directly contradicts the assumption of constancy of light speed in all frames! Is it somehow hard to grasp why? It's very basic, yet it seems to me that we're flogging the horse, here...

First, let me suggest, the rod frame is moving here, it isn't stationary, absolutely, it is moving, absolutely!

Mr Funkstar, you are missing a very interesting physical point, two of them actually. Let us assume for the moment that the frame is moving wrt the stationary frame, OK? At the instant the photons are emitted the test begins. The left photon, lp, is moving toward the oncoming L clock and travels a distance ct during which the physical frame has travelled a distance vt. The right phhoton has travellecd a distance ct to the right and is then a disatnce vt + vt from the right clock R. OK the photons have arrived at the clocks at different times.

That is one, above. Two: When the photons are emitted from the physical midpoint of L and R the physical frame moves away from the emission point, which is an invariant point in space. The photons both move with respect to the emission point, invariant in space and time, hence the velocity of the physical frame can also be measured from the common zero point.
How you might ask will the velocity be measured from this arrangement.

The SOL is the same in the emission point zero frame and as determined in the physical frame, which is moving.

The following is a hypothetical. I am assuming that , in general, the physical frame will be in absolute motion wrt to any point of emission of a photon, which may be untruue, the frame may be at absolute rest. We shall see.

The rp moved a distance ct at the instant the lp has arrived at L after moving an initial distance ct wrt the emission point (only coincidentally also referenced in the Ve). The rp is located a distance of 2vt fromR here. In order to reach R the photon must cross the 2vt plus a tad more that the frame moves while the rp is crossing the 2vt distance, or:

ct' = 2vt + vt'
or t' = t (2v)/(c - v), which is incidentally the measured time difference between a moving and a stationary test. from this then we may calculate v as v = ct'/(2t + t'), so a t' = 0 means v = 0, a t' > 0 means v > 0.

Only if the frame were absolutely at rest would your statement that the photons covered the same rod distance in the same time be true; I anm suggesting you need much more than "theoretical truth" here.. The lp and rp covered the same distance alright, but not the same rod distance. How could photons cover the same rod distance if the frame is moving in the direction of R? Answer: it can't.

A vital point here mr. Funkstar, is that the supposed fact that a human observer "sees no physical frame motion" is scientifically and physically insignificant.

The only thing the observer on the physical frame is 1) the emission of the photons, and 2) the arrival times back at the physical midpoint simultaneously, with the times of the roundtrips embedded in the reflected signals from L and R,; or recovering the slips of paper, two of them, that have the arrival times swtamped on their surface when the photons arrive.

You are saying that the stationary erxperiment will be induistinguishable from obervers on the physically moving frame from the same arrangement with the frame stationary wrt Ve.

SRT negates the motion of the observer theoretically which is a corruption of the integrity of experimental physics ; "don't measure the relative velocity of frame and photon it is always c".

The relative velocity of the frame and photon is always either c + v , or c - v, both of which assume the constant velocity of the speed of light at least during the experiment under discussion. Neither c + v nor c - v physically adds or subtracts velocity of light. The expressions are an accounting of the velocity differences in frame and photon depebnding in the relative ditrection of motion of both.

I have contradicted the fundy of SRT, for sure, so has Mac M, QQ, even SL in a way. James R confirms the errors in SRT by being consistently unable to find specific flaws n the objections raised here. Chroot, a gunslingher from another forum, claiming the highest and most knowledgeable level of physics possible (greater even than Yuriy, who has taught me more about physics than he is aware of) has scorned the dissidents to SRT, but unfortunately he is unable to offer any physical laws, data, argument or whatever that successfully underminds thed dissident's objections. There are many more than one or two objections you know.

Good post Mr. Funkstar, you at least keep the discussion going in the proper direction and have minimized extraneous personal inferences intoyour posts.

Geistkiesel [/indent]

 

[geistkiesel]

Excuse the belated post here, but I was reviewing your post as I found it more intircate in structure and implication than most and I wanted to be sure we were talking about the same thing.

The reason, is that any frame can give us a premise of rest, regardless of it's velocity. That light can travel in all directions the same distance and in the same time equally regardless of the actual velocity of the frame. In fact I think this is exactly how SRT accomodates the postulate of invariance.

yes, but is goes further than that as I see SRT exp-ressed. The invariance prncipoal says that all relative velocity of frame and photon will always be measured as c.. The SOL is c, for sure, but the corruption of SRT says that when measuring the relative velocity of frame and photon that c + V, when frame and photon are moving oppositely from each other, and c - v, when movig parallel to each other, that these expressions actually are only the measurements of the SOL and not the relative motion of frame and photon. SRT negates physical motion and gives it all to the photon.


Geistkiesel​

 

[geistkiesel]

geist a diagram that may clear up this time in continuum thing.

The photon moves from left to right. The numbers are time intervals for the entire frame. 1-6 The frame and the photon have accumulated 6 units of time together.

As the photon is the fastest anything can go and can not go slower than 'c' in a vacuum it makes sense to state that the frame has travelled the same amount of change as the photon has undergone.

The same amount of change in time perhaps, but certainly not distance, as have all the snails in the univese that are whizzing along wrt the photon's FOR.

It can then be further stated that the photon and the frame are not relative in time. The NOW is thus absolute for both photon and frame.
and any velcity the frame has is added to it's inherant 'c' however dilation and length contraction negate any ordinary velocity therefore maintaining that inherent 'c'.

SRT has to say this to survive, but I think SRT does not like to say this outloud, if you know what I mean. The SRT vertainly doesn't emphcize tghe point.

c*v-Length contraction - dilation = 'c' thus light is maintained as invariant for all observers
for example an object travelling at 0.4c

lights v= c*0.4c
when dilation and length contractions are accounted for the v=c thus light's invariance is maintained.

It is remarkable that your assertion that v = c is the correct SRT conclusion, as v is effectively negagted. In other words, c is all there is left to account for in the relative motion measurements.

I would be very confident that the L transforms were created with this premise in mind.....essentially built around E=mc^2. But maybe someone can correct me if I am wrong

This may be so but there is also the obsession to maintian 'equal physics) and Maxwell's equations in 'equivalent frames' that are imbedded in the etiology of SRT.



Geistkiesel​

 

[geistkiesel]

James R's thought experiment assumes the invariance principle. geistkiesel claimes to refute his analysis based on an assumption of absolute space and time. Do you (both you and geistkiesel) see why this doesn't work?

Hint: The invariance principle and absolute space and time are incompatible.

You have stated an erroneous assertion here Funk. I have never assumed an 'absolute space and time" and then proceeded with my gedanken. The absoluteness of space and time are deduced from analysis of the experiment under consideration; you seemed to have missed this point; but then you wouldn't have brought it up if you had recognized that is was conclusion from analysis that you were complaining against, would you? Or then maybe you would have, who knows the answer to this other than funkstar?

SRT, and you then, have assumed that the meaurement of the relative velocity of frame and photon will always result in the value 'c'. It wont unless, of course, SRT negates the velocity and very motion of the physical frame, which is what SRT does. Check it out!!.

Funkstar will you admit, agree or do you "see" that SRT equates the measurement of the relative velocity of frame and photon with the measurement of the speed of light, period?
Geistkiesel​

 

[Quantum Quack]

I guess it;s sort of like If I am in a truck moving north and I see a car coming towards me obviously the faster I go towards the truck the faster the truck appears to be moving however my increase in speed does not alter the trucks speed. None in the slightest, only our relative speed is changed.
Now a photon is moving towards you and you are moving towards it. Obviously the photon will appear to be faster if you increase your speed but just increasing your speed doesn't make the photon travel any quicker.

What SRT has to do because of the invariance of light, dilate the time and contract the length of our car so that light appears to be traveling the same v. to us in the car. Now SRT has to do this for reasons beyond just mere convenience.

If light is indeed invariant then the transforms are a necessary reality. However as I have posed before this does not in any way negate simultaneity. And it is only SRT that makes simultaneity an issue.

I will be posting a thread soon with a discussion on the possible physical reasons for dilation and contraction.

digging into why E=mc^2 requires the transforms to maintain it's integrity regardless of RF.

The problem with your proposition Geist IMO, is that the event of a photon emmission is a zero duration event, the emitter can be at any velocity but at that precise moment of emmision it is in a zero duration and zero velocity moment. At that zero duration moment it could be said to be still but only for a zero amount of time.

Thus you are correct that the source of the light determines an absolute velocity however that source is constantly moving and when the emmission occurs it is in a state of movement but at the very moment of emision it is at the cusp of an event horizon. It never is still to give you that absolute v figure.

this diagram may help

The moment of photon creation is passed as soon as it happens sort of thing. So the emmission point in time may be zero but the velocity of that point can not be arrived at simply because it has no duration in time because the emmitter is in constant movement.

 

[geistkiesel]

I'm asking you where the absolute rest frame is. If you claim that there's some "memory" of relative acceleration, then what that relative acceleration was originally with respect to, is a very reasonable question.

I do not want to answer for MacM, but from my analysis all acceleration of all FORs wrt the embankment, the earth surface, must have necessarily accelerated such that a relative motion was opbserved in the first instance. The Ve does not accelerate, only all other FIORs, wrt the Ve that is.

Therefot\re SRT's assumption that the moving observer may consider himself at rest wrt Ve is physically impossible, and the fact that you can manipulate mathematical equations to equate this impossible physical state to a moving earth surtface has no physical significance.

The "at rest assumption" can easily be proved erroneous if the above statements regarding the acceleration of the moving frame wrt Ve isn't enough for you.
Two expanding photon spheres have an invariant midpoint located in a uniq1ue position in the universe. Tqo photons emitted from a common source wahever the motion of the source of the photons define a unique point in space that is eternally invariant. The fact that you may have technilogical problems of finding those points in space is not to negate the reality of those points. What more do you need? What do you find objectionable about the photon motion defining measurable points in space? I am not using the photon speed as a frame of reference I use the points defined by one or two photons as an invariant point in sopace because the velocity is the same for all the photons. So what that this contradicts SRT and the "invariance principal"? Haven't you ever heard of physical theories giving way to progessive substitutions? Of course you have, but you have always considered that you would end up on the prevailing and "truthful' side correct?

Shall we discuss the personalities of observers as necessary to establish the physical fact pf the invariant position in space of the emission point of photons?? Shall we discuss the observrers' "point of view?" wrt the midpoints of expanding photon motion as necessary attributes of establishing the invariance of the midpoints?? You have recognized that some human points of vierw can be illusory haven't you? I know, it is all the SRT dissident's POVs that are in error, correct? Do we need observers to agree on the reality of the midpoints and the fact that the trajectory of the photons give a standard of constant velocity measurement from which we may determine the physical frame's absolute motion in space and time?

Geistkiesel​

 

[Quantum Quack]

geist, sorry to jump in.
But to ascertain a velocity we need at least two events. Now if both these events are zero in duration and zero velocity but the photons are still emitted as 'c' it is impossible to determine the velocity of the emitter by using photons because no matter which event you wish to consider it still has zero velocity and zero duration.

so the question is how can we determine the absolute velocity of a moving frame when at all times the emitter has zero duration and zero velocity?

The emission point velocity is always zero regardless of how fast or slow the frame is moving.

 

[geistkiesel]

I guess its sort of like If I am in a truck moving north and I see a car coming towards me obviously the faster I go towards the truck the faster the truck appears to be moving however my increase in speed does not alter the trucks speed. None in the slightest, only our relative speed is changed.
Now a photon is moving towards you and you are moving towards it. Obviously the photon will appear to be faster if you increase your speed but just increasing your speed doesn't make the photon travel any quicker.

What SRT has to do because of the invariance of light, dilate the time and contract the length of our car so that light appears to be traveling the same v. to us in the car. Now SRT has to do this for reasons beyond just mere convenience.

If light is indeed invariant then the transforms are a necessary reality. However as I have posed before this does not in any way negate simultaneity. And it is only SRT that makes simultaneity an issue.

I will be posting a thread soon with a discussion on the possible physical reasons for dilation and contraction.

digging into why E=mc^2 requires the transforms to maintain it's integrity regardless of RF.

The problem with your proposition Geist IMO, is that the event of a photon emmission is a zero duration event, the emitter can be at any velocity but at that precise moment of emmision it is in a zero duration and zero velocity moment. At that zero duration moment it could be said to be still but only for a zero amount of time.

Thus you are correct that the source of the light determines an absolute velocity however that source is constantly moving and when the emmission occurs it is in a state of movement but at the very moment of emision it is at the cusp of an event horizon. It never is still to give you that absolute v figure.

this diagram may help

The moment of photon creation is passed as soon as it happens sort of thing. So the emmission point in time may be zero but the velocity of that point can not be arrived at simply because it has no duration in time because the emmitter is in constant movement.

You are correct of what SRT must do for convenience, convenience of survival as a theory that is: negate the motion of the observer, ergo all measurments of relative velocity of frame and photon will always reult in a measurement of C for the relative motion of the frame and photon which is different than the measurment of the SOL, correct?

QQ, you are correct, the physical source may be moving, but the point in space where the photons were emitted is not moving. It is easiest to see when two photons are emitted in opposite directions simultaneously. The expanding distance between them is measured from the point of emission and where and what the physical emitter has done or is doing, is of absolutely no consequence. Those insisting that somehow the physical point of emission after emission has some physical meaning regarding the motion of the light are not using the laws of physics consistently; as if measured by the 'position of the emitter' has some significance with the zero point defined by the midpoint of oppositely moving photons. The physical emmitter has significnce, not for its motion, but for the emission of photon only, thus giving us something to discuss.

James R started a thread on defi9nitions of FORs. There he stated, quite accurately, that the FOR need not be a physical object and in general the FOR is merelyt an abstraction. However, to be useful the sbatraction must accurately mirror the physical reality it claims it is describing. I do not draw a portrait of a beautiful woman by painting the canvas black and thne claiming that only the blind and the artistic dullards are unable to see the beauty of the beautiful blond I have so clearly drawn. Well i do niot do this and believe iot myself, even were I to convicnce others to say "Oh yes, now I see her." If they do "see her" the 'black' is but a frame for the viewer's own projection, which is a justifiable artistic dynamic, but a 'pure black painting' an't a beautiful blond, now is it?

Let us take this to the opposite extreme: A photon burst occurs NOW on opposite ends of the universe, NOW. The expanding photon spheres can be said to have a shortest distance between unique points on each expanding sphere's surface (the spheres do not necessarily have to have errupted simultaneously, only that two spheres exist NOW).

We need only discuss the point of shortest distance between mutually opposing photon motion and hence, the midpoint between the photons of closest distance is invariant is it not? For all NOW? I am assuming the constancy of the SOL in open space, far removed from any gravitational or other possible physical perturbations.

Human observers are relevant only if they are using the defined absolute FOR in their navigation dynamics, for one example.
Geistkiesel​

 

[Prosoothus]

Nice to see sciforums back up. I missed this place.

superluminal,

So what you are saying is that 'c' (in a vacuum) may be measured to be different if it was measured well outside of a gravitational field?

I'm saying that an observer that is stationairy in a gravitational field, no matter how weak the field, will always measure the speed of light to be equal to c. However, an observer that is moving through a gravitational field, no matter how weak the field, will measure the speed of light to be equal to c +- the velocity that the observer is moving through the field.

 

[GMontag]

I'm saying that an observer that is stationairy in a gravitational field, no matter how weak the field, will always measure the speed of light to be equal to c. However, an observer that is moving through a gravitational field, no matter how weak the field, will measure the speed of light to be equal to c +- the velocity that the observer is moving through the field.

That is obviously wrong. We are moving through the sun's gravitational field and yet we still measure the speed of light to be c.

 

[Prosoothus]

GMontag,

That is obviously wrong. We are moving through the sun's gravitational field and yet we still measure the speed of light to be c.

We are moving through the Sun's gravitational field at 30,000 m/s, but the Sun's gravitational effect on light on the surface of the Earth is 1650 times weaker that the Earth's gravitational effect on that same light. As a result, the Sun's gravitational field does influence the speed of light on the surface of the Earth, but it's influence is small (it only changes the speed of light by about 9 m/s).