[mad aetherist (OP)]

G Burniston Brown blows another hole in Einstein's silly elevator equivalence thort-X.
https://www.big-lies.org/modern-physics-a-fraud/modern-physics.html#relativity

To overcome the physical difficulty that acceleration produces forces (inertial) whereas uniform velocity does not, Einstein was led to assert that these forces cannot be distinguished from ordinary gravitational force, and are therefore not an absolute test of acceleration. This contention Einstein called the principle of equivalence. In trying to support this contention, he imagined a large closed chest which was first at rest on the surface of a large body like the Earth, and then later removed to a great distance from other matter where it was pulled by a rope until its acceleration was g . No experiment made inside could, he claimed, detect the difference in the two cases.

But in this he was mistaken, as I have shown (Brown 1960). In the first case, if two simple pendulums were suspended with their threads a foot apart, the threads would not be parallel but point towards the centre of mass of the Earth (or a point somewhat nearer allowing for their mutual attraction). The angle between them would, in principle, be detectable by the Mount Palomar telescope.
When accelerated by a rope, the threads would be parallel if it were not for the small mutual attraction.
If now, the threads were moved so as to be further apart, the angle between them would increase in the first case, but in the second case the threads would become more parallel so that the angle would therefore decrease.
The principle of equivalence is therefore untenable.

It is gratifying to find one theoretician who states that the principle is false (Synge 1960):
“In Einstein’s theory there is a gravitational field or there is none, according as the Riemann tensor does or does not vanish. This is an absolute property: it has nothing to do with the observer’s world-line.”

The principle of equivalence is made plausible by the use of the expression ‘gravitational field’, overlooking the fact that this is a useful conception but cannot be demonstrated. All we can do is place a test particle at the point in question and measure the force on it. This might be action-at-a-distance.

As soon as the term ‘field’ is dropped and we talk about the gravitational force between bodies at rest, we realize that the force is centripetal, whereas the force of inertia is not. This is an important difference obscured by the use of the word ‘field’. Relativists now admit that the principle of equivalence only holds at a point; but then, of course, we have left physics for geometry – experiments cannot be made at a point.

[Kryptid]

The equivalence principle is only an approximation. It's well known that sufficiently precise equipment (or a sufficiently large elevator) can reveal whether you are at rest on a planet or in an accelerating elevator.

[Halc]

In trying to support this contention, he imagined a large closed chest which was first at rest on the surface of a large body like the Earth, and then later removed to a great distance from other matter where it was pulled by a rope until its acceleration was g . No experiment made inside could, he claimed, detect the difference in the two cases.

Einstein imagined a small chest, not a large one.  He asserted that no local experiment could detect the difference.  Putting two plumb lines a foot apart with instruments sufficiently sensitive to detect the angle constitutes a non-local test.

[Petrochemicals]

I thougt the idea was you do not know you are accelerating unless there is an external gravity field acting on you ?  Whether you hit and feel the source of the field is not relevant really.

An elevatir shaft  through the centre of the earth higher than the atmosphere, if you pass the earth over an elevatort, the elevator would be attracted to the central gravitational point, chaseing  the centre until escaping from the gravitational attraction. It would not feel any resistance.

[mad aetherist (OP)]

The equivalence principle is only an approximation. It's well known that sufficiently precise equipment (or a sufficiently large elevator) can reveal whether you are at rest on a planet or in an accelerating elevator.

Yes the equivalence principle is only an approximation. The non-approximation corollary is that an accurate experiment  can show that there is no equivalence. So, naturally, Alby & friends were happy to put all logic aside & go for "yes" -- their only difficulty was re what to call this nearly allmost nearnuff case of sort of equivalence, what do u call something that is patently nontrue -- why, of course, call it a principle -- when at the same time knowing that non-equivalence was the truth, Alby & friends simply ignored the true non-equivalence -- & by ignoring it, well, no name needed (hey everybody look over there at that blackhole).

14Dec2018-- i see that Alby actually called it a law...............
          We must note carefully that the possibility of this mode of interpretation rests on the fundamental property of the gravitational field of giving all bodies the same acceleration, or, what comes to the same thing, on the law of the equality of inertial and gravitational mass. If this natural law did not exist, the man in the accelerated chest would not be able to interpret the behaviour of the bodies around him on the supposition of a gravitational field, and he would not be justified on the grounds of experience in supposing his reference-body to be “at rest.”

[mad aetherist (OP)]

In trying to support this contention, he imagined a large closed chest which was first at rest on the surface of a large body like the Earth, and then later removed to a great distance from other matter where it was pulled by a rope until its acceleration was g . No experiment made inside could, he claimed, detect the difference in the two cases.

Einstein imagined a small chest, not a large one.  He asserted that no local experiment could detect the difference.  Putting two plumb lines a foot apart with instruments sufficiently sensitive to detect the angle constitutes a non-local test.

Yes. Einsteinians were frantic, what to do, everyone could see that the elevator thort-X was complete krapp -- & then a masterstroke, why, of course, Alby meant at a point, ah, problem solved, that should keep skoolkids happy for a while untill they grow up, at which time we will invent some other pseudo excuse.

So, u are not allowed to have an experiment that has width. What this really means is that u are not allowed to have an elevator that has width. So, Einstein's equivalence principle only applies to elevators with no width or width. And, if u come up with an experiment that involves height, well, no problem, we will simply extend that to include that an elevator must not have any widths, nor any height. Ok now what can u come up with -- can u come up with an experiment that has no widths & not height -- no, oh, poor poor anti-relativist -- better luck next time (hey everyone look over there, a black hole).

Re plumb lines on Earth -- look up Tamarack Mine -- lots of stuff re this stuff.
https://www.lockhaven.edu/~dsimanek/hollow/tamarack.htm
https://www.lockhaven.edu/~dsimanek/hollow/morrow1.htm
http://www.phy.mtu.edu/alumni/history/DMGPlumbLines.pdf
https://www.theflatearthsociety.org/forum/index.php?topic=62189.0

[mad aetherist (OP)]

I thought the idea was you do not know you are accelerating unless there is an external gravity field acting on you ?  Whether you hit and feel the source of the field is not relevant really.

No i think that equivalence means that it is difficult to know whether the force on your feet-legs is due to gravity (& zero acceleration of the elevator) or due to inertia (due to acceleration of the elevator). Which is nearnuff true, but aint exactly true, so, not being exactly true Alby & mates decided to call it a Principle. If it were exactly true then they would hav kum in their undies, & would have had a sticky time looking for a good enuff word. Lemmesee now, what is better than Principle -- praps Law -- no, not good enuff -- they would want something heavenly -- yes, i know, if equivalence were true then they would have called it a Commandment -- the Equivalence Commandment -- that would make it Commandment 16 i think -- or in the Jewish Bible it would be No 170 or something (hey everybody, look, whats that over there, i think its a blackhole).

An elevator shaft  through the centre of the earth higher than the atmosphere, if you pass the earth over an elevator, the elevator would be attracted to the central gravitational point, chasing  the centre until escaping from the gravitational attraction. It would not feel any resistance.

I aint an expert, but i reckon that looking at elevators near or inside Earth is a problem -- u have to look out for spinning & orbiting centrifugal effects etc.

[set fair]

But in this he was mistaken, as I have shown (Brown 1960). In the first case, if two simple pendulums were suspended with their threads a foot apart, the threads would not be parallel but point towards the centre of mass of the Earth (or a point somewhat nearer allowing for their mutual attraction). The angle between them would, in principle, be detectable by the Mount Palomar telescope.

Are you sure about this? Gravity would be stronger at the bottom of the pendulum (~ space more curved and time slowed down). So whether you used a ruler or a light to measure the separation the threads may still appear parallel.

[Halc]

So, u are not allowed to have an experiment that has width.

Local, so no significant depth either.  If your experiment relies on a field difference over a distance, it is not a local test.  The restriction is lifted for a uniform gravitational field.  A uniform gravitational field is indistinguishable from acceleration at any size box.

General relativity is a local theory, as is it derived from special relativity, which says that nothing can move faster than c inside a box.  Things can move faster outside it.

And, if u come up with an experiment that involves height

Like detection of tides.  There are no tidal forces in a uniform gravitational field.

[mad aetherist (OP)]

So, u are not allowed to have an experiment that has width.

Local, so no significant depth either.  If your experiment relies on a field difference over a distance, it is not a local test.  The restriction is lifted for a uniform gravitational field.  A uniform gravitational field is indistinguishable from acceleration at any size box.

Ok SR is trumped by GR, but uniform gravitation is impossible, which opens up another avenue for non-equivalence (alltho i suppose that that is where Brown was anyhow).
How about if we shine a light across the elevator. The light beam bends down. In a gravitational field the photons hitting the far wall will be aiming-progressing on a downward angle. In an inertial field the photons will at all times be aiming horizontally, but progressing on a downward angle.

General relativity is a local theory, as is it derived from special relativity, which says that nothing can move faster than c inside a box.  Things can move faster outside it.

I reckon that a one-way (DeWitte) speed of light experiment would show anisotropy. And an MMX would show anisotropy. For both a gravitational field & an inertial field. The anisotropy would not be equivalent, but there would not be any surefire way of determining which kind of field it was -- depending on the specified circumstances -- partly because the anisotropy must change with time in both cases.

And, if u come up with an experiment that involves height

Like detection of tides.  There are no tidal forces in a uniform gravitational field.

The only height issue that i can think of is that in a gravity field a clock near the ceiling might tick faster than a clock near the floor, whilst in the inertial case the ticking would be the same.

[Colin2B]

Are you sure about this? Gravity would be stronger at the bottom of the pendulum (~ space more curved and time slowed down). So whether you used a ruler or a light to measure the separation the threads may still appear parallel.

You would also be hard pushed to find a place (or two) where the plumb lines definitely point towards the centre of the earth.
As @Halc said, we can only rely on local measurements.

PS @Halc you say “but uniform gravitation is impossible”. It can be done, look up spherical cavity in a solid uniform sphere. I agree that it is tricky to achieve 

[mad aetherist (OP)]

Are you sure about this? Gravity would be stronger at the bottom of the pendulum (~ space more curved and time slowed down). So whether you used a ruler or a light to measure the separation the threads may still appear parallel.

You would also be hard pushed to find a place (or two) where the plumb lines definitely point towards the centre of the earth. As @Halc said, we can only rely on local measurements.

If u had lots of pairs of lines on various horizontal angles then one of thems pairs will be nearnuff pointing to center of Earth (the others will be pointing off center due to centrifugal force). But anyhow all i have to do is specify that the massive body is not rotating or spinning or orbiting.

PS @Halc you say “but uniform gravitation is impossible”. It can be done, look up spherical cavity in a solid uniform sphere. I agree that it is tricky to achieve 

Yes but once again that is a special case. Equivalence is not proven simply because a relativist can find one special case where relativists & anti-relativists all agree that there must be equivalence in that particular case. Conversely all that anti-relativists need do is find one case of any kind where there is or might be no equivalence.

[Halc]

Ok SR is trumped by GR, but uniform gravitation is impossible, which opens up another avenue for non-equivalence

Yea, well continuous acceleration is similarly impossible, so we could violate locality by a test that extends the temporal size of our box.  Wait to see if the acceleration stops.  That's a non-local test to distinguish between the two.

How about if we shine a light across the elevator. The light beam bends down. In a gravitational field the photons hitting the far wall will be aiming-progressing on a downward angle. In an inertial field the photons will at all times be aiming horizontally, but progressing on a downward angle.

But no difference in an accelerating box.  Both beams bend down.  Using the equivalence principle is how they made the prediction that gravity would bend light.

The only height issue that i can think of is that in a gravity field a clock near the ceiling might tick faster than a clock near the floor, whilst in the inertial case the ticking would be the same.

But an accelerating box is not inertial.  So the clock at the top of the box ticks faster than the one at the bottom.

[mad aetherist (OP)]

But in this he was mistaken, as I have shown (Brown 1960). In the first case, if two simple pendulums were suspended with their threads a foot apart, the threads would not be parallel but point towards the centre of mass of the Earth (or a point somewhat nearer allowing for their mutual attraction). The angle between them would, in principle, be detectable by the Mount Palomar telescope.

Are you sure about this? Gravity would be stronger at the bottom of the pendulum (~ space more curved and time slowed down). So whether you used a ruler or a light to measure the separation the threads may still appear parallel.

My gut feeling is that the true angle & the perceived angle of radial plumb threads are not affected by gravity. If gravity were not stronger at the bottom of the line then the thread would not point, it would just float around. If the gravity is stronger at the bottom of the thread then that there gravity cant on one hand give the thread an angle & on the other hand change that angle.

The use of light to measure separation is complicated. My gut feeling is that light would give the impression that the separation at the bottom is larger than it is, & the threads might appear or at least be measured to be parallel.
But a solid rod would not be affected as much as is light. It would show that the threads are not parallel. According to GR the length of rods is only affected in the radial direction, hencely the length of a straight rod would be slightly affected when moved from top to bottom of the pair of threads, & so would not be a perfect measure, it would rob the true angle just a little (ie praps it would measure 0.999999 of the true angle)(base on say Earthly numbers).

I have a problem with the general argument here anyhow. I think that Popper would not entirely approve. If an anti-relativist describes a situation where the elevator thort-X equivalence principle is violated, then Popper might choke on his sandwich if a relativist uses a prediction based on the elevator thort-X to defend the elevator thort-X equivalence principle. 

[Halc]

PS @Halc you say “but uniform gravitation is impossible”. It can be done, look up spherical cavity in a solid uniform sphere. I agree that it is tricky to achieve 

I meant the equivalent of an accelerating box, where your weight is identical anywhere in the box.  The spherical cavity results in zero weight everywhere, the equivalent to an inertial frame, but still in a gravity well.

Not sure how that can be done with gravity.  You can however get arbitrarily close.  On Earth at 1g of acceleration, my weight drops off by 4/100th of a percent if I move up one meter.  But if I am held stationary at a point near Sgr-A where the gravity is similarly 1g, a 1-meter movement results in an undetectable difference in weight.  The force is the same there, but the field far more uniform.

[mad aetherist (OP)]

Ok SR is trumped by GR, but uniform gravitation is impossible, which opens up another avenue for non-equivalence

Yea, well continuous acceleration is similarly impossible, so we could violate locality by a test that extends the temporal size of our box.  Wait to see if the acceleration stops.  That's a non-local test to distinguish between the two.

No, a thort-X allows all sorts of non-practical assumptions.

How about if we shine a light across the elevator. The light beam bends down. In a gravitational field the photons hitting the far wall will be aiming-progressing on a downward angle. In an inertial field the photons will at all times be aiming horizontally, but progressing on a downward angle.

But no difference in an accelerating box.  Both beams bend down.  Using the equivalence principle is how they made the prediction that gravity would bend light.

No. Think it throo. In the inertial case the photon retains its heading at all times.

The only height issue that i can think of is that in a gravity field a clock near the ceiling might tick faster than a clock near the floor, whilst in the inertial case the ticking would be the same.

But an accelerating box is not inertial.  So the clock at the top of the box ticks faster than the one at the bottom.

I dont understand.  All clocks anywhere in the accelerating elevator must tick the same. The only possible problem being how to measure all of their tickings.

[Halc]

If gravity were not stronger at the bottom of the line then the thread would not point, it would just float around.

Nonsense.  Any gravity/acceleration will make a plumb-line point a certain way.  It need not be stronger at the bottom for this to be true.
Example is a plumb line in a coal mine, where gravity is weaker near the bottom of the line, and strongest at the top.  Plumb lines still work in mines.

Yes, I agree that widely separated plumb lines will point different ways if they're near the gravity source.  Geometry demands that.  It is a non-local test after all.

But a solid rod would not be affected as much as is light. It would show that the threads are not parallel. According to GR the length of rods is only affected in the radial direction,

Does gravity have any effect on the radial length of something?  Speed does of course, but all objects in question here are stationary in their respective frames (the frame of the box).

You're looking for relativistic details in a straightforward Newtonian example.  Make the box 10000 km wide and notice that the plumb lines are perpendicular.  Length contraction from trivial gravity of Earth (if there is such a thing at all) isn't going to hide that.
If you're going to break the rules, do it right.

[Halc]

but uniform gravitation is impossible

Yea, well continuous acceleration is similarly impossible, so we could violate locality by a test that extends the temporal size of our box.  Wait to see if the acceleration stops.  That's a non-local test to distinguish between the two.

No, a thort-X allows all sorts of non-practical assumptions.

Then there is no problem with the uniform gravitational field to which the continuous acceleration is being compared.  It is quite possible, just not practical.

No. Think it throo. In the inertial case the photon retains its heading at all times.

The accelerating box is not inertial.

dont understand.  All clocks anywhere in the accelerating elevator must tick the same.

Not so.  Theory of relativity says otherwise. Different inertial frames would order separated events in the same order for this to be true, but SR shows that event ordering is frame dependent.

The only possible problem being how to measure all of their tickings.

Observers at either end are quite capable of watching the clocks at the far end, and noticing that they don't run at the same rate.

[Halc]

Like detection of tides.  There are no tidal forces in a uniform gravitational field.

An intersting correction: There are no classical (Newton, Kepler) tides in a uniform gravitational field.
If clocks tick faster at the top of both boxes, then to maintain the uniform vertical dimension of the box, the acceleration up at the top must be less than the acceleration at the bottom.  Less acceleration means less force.  You weigh less at the top of the box even in a perfectly uniform gravitational field or in an accelerating box.  That difference in force will produce tidal effects in both the gravity and the accelerating box.  A bar that is allowed to spin freely will tend to align itself vertically.

Relativistic tides drop off with the square of the distance from the gravitational source, not the cube of the distance as with classical tides.  So the relativistic tide from the sun is stronger than that from the moon, but both are dwarfed by the classic tides from those sources.

I already knew all this from my long-ship thread, where the occupants at the back of the ship are killed by my unreasonable G forces, yet those at the front are experiencing a tiny fraction of 1 g.

[mad aetherist (OP)]

If gravity were not stronger at the bottom of the line then the thread would not point, it would just float around.

Nonsense.  Any gravity/acceleration will make a plumb-line point a certain way.  It need not be stronger at the bottom for this to be true.

Yes u are correct, gravity need not be stronger at the bottom for the thread to be straight & tight -- but this of course a side issue & not critical to equivalence.

Example is a plumb line in a coal mine, where gravity is weaker near the bottom of the line, and strongest at the top.  Plumb lines still work in mines.

Yes. Just as an aside last month i learnt that nearer the central iron core the value of g increases with depth (after decreasing with depth nearer Earth's surface.

Yes, I agree that widely separated plumb lines will point different ways if they're near the gravity source.  Geometry demands that.  It is a non-local test after all.

Yes, depending on TD & LC effects affecting measurement etc.

But a solid rod would not be affected as much as is light. It would show that the threads are not parallel. According to GR the length of rods is only affected in the radial direction,

Does gravity have any effect on the radial length of something?  Speed does of course, but all objects in question here are stationary in their respective frames (the frame of the box).

Yes my understanding of GR is that rods are shortened in the radial direction only, not tangentially. Light can be affected in all directions because the ticking dilation factor comes into play with light what with frequency & wavelength -- eg if u use lightwaves to measure length. Yes relative V is zero in the elevator, so isnt a factor.

You're looking for relativistic details in a straightforward Newtonian example.  Make the box 10000 km wide and notice that the plumb lines are perpendicular.  Length contraction from trivial gravity of Earth (if there is such a thing at all) isn't going to hide that.  If you're going to break the rules, do it right.

I think that u are referring to the unwritten rule that Einstein's elevator must have zero width & zero length & zero height. This would be laughed out of court. So, Einsteinians mask this by saying that the experiment must have zero width length height -- yes, that looks much better (hey everyone look at that blackhole over there).
Or u might be referring to the unwritten rule that Einsteinians can use the principle being argued about to prove their case.  Its a bit like me say saying that 2 plus 2 = 5, & then in my proof saying 5 minus 2 = 2 (because 2 plus 2 = 5). Popper would choke on his sandwich.