[mad aetherist (OP)]

Anyhow i reckon that in an elevator in free fall..
(1) In free-fall in deep outer space a beam of light from a distant star entering a small hole would remain straight (& hit the far wall).  This is based on this being a ballistic Newtonian bending (which cancels the bending due to free-fall).

Not a local test.  You're looking out of the window.

If u like u can shine a light beam from wall to wall inside. Possibly the same thing.
[17dec2018-- I AM FAIRLY CERTAIN THAT EINSTEIN HAD A RAY OF LIGHT ENTERING HORIZONTALLY AT THE MIDDLE OF ONE WALL.]

(2) In free-fall in a gravity field (near a planet) the beam would curve (& hit the far wall). This is based on an Einsteinian bending which is twice the Newtonian.
So here the observer would be able to tell whether in a gravity field based on there being a curve or not.

A legit test, but both should be straight.  So where do you get this "Einsteinian bending which is twice the Newtonian"?

I thort that Einsteinians all agreed that the bending at the Sun is 1.75 arcsec whilst the Newtonian ballistic prediction is 0.875 arcsec, which is in effect 2:1.  But i am surprised that u consider that both should be straight, i would have thort that Einsteinians would insist that both be curved.

If the Einsteinian bending = the Newtonian bending then the beam might be straight in both (2) &(1).
But in (1) the individual photons would remain pointing in line with the beam at all times,  whilst
in (2) the photons would gradually yaw (in the vertical plane) & would be crabbing along the line of the beam & would be pointing on a different vertical angle to the beam especially at the end (the curved beam being their traject).

I'm sorry, but the English is so poor here, I cannot parse this.  No idea what 'crabbing' is, or what it would mean for a photon to 'yaw' or 'point', or for that matter what you think would cause it to do so.  Photons get measured when the interact with something. Yaw means that the thing twists sideways while moving, but without changing trajectory, sort of like a car sliding sideways on the ice.

Yes yaw is a rudder thing. If one considers that a photon is shaped like a bullet then in (1) the bullet follows a straight traject & at all times the bullet maintains its initial "aim" or "heading", ie it points in the same direction all the way, ie in this case it points exactly along its straight traject all the way, whilst in (2) the bullet follows a straight traject but the bullet as u say slides sideways (crabs), the crabbing getting worse & worse & being at a max when it hits the wall.

Re yawing & pointing, there is no real need to insist on having any beam curving in some sort of vertical plane (there is no vertical in free-fall anyhow), the curving yawing pointing can be allowed to happen in any plane, doesnt really matter.  I just mentioned the vertical because yawing is usually associated with the horizontal plane, but if there is any curving then the yawing & pointing will occur in the plane of the curving.

No matter which plane it is.  I claim any beam appears to be straight for both observers.
If there is a gravity field, I suppose that defines which way is vertical even in free fall, even if the observer cannot detect it.  You are free to talk about it.
If the observer can determine which way is vertical with a local test, that's something the guy in space cannot do, so that would be a distinction.

If the beam is straight then if the photon-bullet is at all times in line with the beam then that indicates no gravity field -- or if the photon-bullet is crabbing-skidding then that indicates the presence of a gravity field, & the common plane of the photon-bullet's centerline & the line of the beam indicates the plane that contains the line of action of the gravity field -- & the general direction of the nose of the photon-bullet indicates the general direction -- but the exact line of action of the field might not be determinable (there might be some other test that helps here).
But i am surprised that u went for (B), i thort Einsteinians would go for (A). I modified my earlier thread, there is also a (C).

[Halc]

If u like u can shine a light beam from wall to wall inside. Possibly the same thing.

That's fine.  The bean should be measured by the observer to go straight across in both cases.

I thort that Einsteinians all agreed that the bending at the Sun is 1.75 arcsec whilst the Newtonian ballistic prediction is 0.875 arcsec, which is in effect 2:1.

Yes.  Newton was wrong.  There is no Newtonian bending.

But i am surprised that u consider that both should be straight, i would have thort that Einsteinians would insist that both be curved.

Not from the frame of either observer in either box.

Yes yaw is a rudder thing. If one considers that a photon is shaped like a bullet then in (1) the bullet follows a straight traject & at all times the bullet maintains its initial "aim" or "heading", ie it points in the same direction all the way, ie in this case it points exactly along its straight traject all the way, whilst in (2) the bullet follows a straight traject but the bullet as u say slides sideways (crabs), the crabbing getting worse & worse & being at a max when it hits the wall.

Photons don't have a shape, and don't yaw.  They are measured at certain points, which in this case will be a spot on the wall directly opposite the source of the light.  If it is a beam, it might be measured in the path between as it is defected by dust and such.  That beam will be observed to be straight in this freefall case.

If the beam is straight then if the photon-bullet is at all times in line with the beam then that indicates no gravity field -- or if the photon-bullet is crabbing-skidding then that indicates the presence of a gravity field

If you're going to propose this, you're going to have to indicate how one might measure the way a photon points at the event of measurement.  One can only measure a photon once, per Heisenberg.
From my point of view, you're making up total fiction.

[mad aetherist (OP)]

If u like u can shine a light beam from wall to wall inside. Possibly the same thing.

That's fine.  The beam should be measured by the observer to go straight across in both cases.
Comment: I think that it is ok to insist on non-local inputs. However in the case of my far-away starlight i think that that should be acceptable, after all i am only using it to provide a constant (& a straight & aligned photon) photon input, its not as if i am checking on its frequency or something.
Re the beam going straight across in both cases -- i will address this in its own posting later today.
[17dec2018-- I AM FAIRLY CERTAIN THAT EINSTEIN HAD A RAY OF LIGHT ENTERING HORIZONTALLY AT THE MIDDLE OF ONE WALL.]

I thort that Einsteinians all agreed that the bending at the Sun is 1.75 arcsec whilst the Newtonian ballistic prediction is 0.875 arcsec, which is in effect 2:1.

Yes.  Newton was wrong.  There is no Newtonian bending.
Comment:  Einstein in 1911 got 0.83~0.875 arcsec for bending due to time (the time in spacetime) & in 1915 added 0.87~0.875 arcsec for space (the space in spacetime) to get  1.7~1.75 arcsec.  Soldner got 0.83~0.875 arcsec in 1805 (?) using a ballistic calculation, which we call the Newtonian value.  The 0.875 arcsec & 1.75 arcsec are using modern numbers for Sun's mass & G etc.  Yes i think that Einstein didnt directly include any Newtonian-ballistic bending in his figures (but praps indirectly), & the Soldner 0.83~0.875 arcsec might be a co-incidence (or it might be an automatic outcome what with Einstein's stuff riding on the back of Newton's stuff).

But i am surprised that u consider that both should be straight, i would have thort that Einsteinians would insist that both be curved.

Not from the frame of either observer in either box.
Comment: I will address this later today..

Yes yaw is a rudder thing. If one considers that a photon is shaped like a bullet then in (1) the bullet follows a straight traject & at all times the bullet maintains its initial "aim" or "heading", ie it points in the same direction all the way, ie in this case it points exactly along its straight traject all the way, whilst in (2) the bullet follows a straight traject but the bullet as u say slides sideways (crabs), the crabbing getting worse & worse & being at a max when it hits the wall.

Photons don't have a shape, and don't yaw. 
Comment:  This is the crux of the issue.  I will address this in a separate posting later today.
They are measured at certain points, which in this case will be a spot on the wall directly opposite the source of the light.  If it is a beam, it might be measured in the path between as it is defected by dust and such.  That beam will be observed to be straight in this freefall case.
Comment:  Yes measurements at various points will show whether straight or curved.

If the beam is straight then if the photon-bullet is at all times in line with the beam then that indicates no gravity field -- or if the photon-bullet is crabbing-skidding then that indicates the presence of a gravity field

If you're going to propose this, you're going to have to indicate how one might measure the way a photon points at the event of measurement.  One can only measure a photon once, per Heisenberg. From my point of view, you're making up total fiction.   
Comment:  Yes i dont know how we might measure which way a photon is pointing (ie whether it is crabbing), especially with ultra-small values. I will think about this & address it separately later today.
The measurement would of course be made at the far wall. If photons are destroyed during measure then that aint a worry.  Heisenberg's stuff is nonsense (but not relevant here)(& not relevant anywhere else).  The fiction is Einstein's, as i will show.

[mad aetherist (OP)]

If the beam is straight then if the photon-bullet is at all times in line with the beam then that indicates no gravity field -- or if the photon-bullet is crabbing-skidding then that indicates the presence of a gravity field

If you're going to propose this, you're going to have to indicate how one might measure the way a photon points at the event of measurement.  One can only measure a photon once, per Heisenberg. From my point of view, you're making up total fiction.  
Comment:  Yes i dont know how we might measure which way a photon is pointing (ie whether it is crabbing), especially with ultra-small values. I will think about this & address it separately later today.
The measurement would of course be made at the far wall. If photons are destroyed during measure then that aint a worry.  Heisenberg's stuff is nonsense (but not relevant here)(& not relevant anywhere else).  The fiction is Einstein's, as i will show.
Ok i had a think.  I crunched some numbers in Excel.  For a 10 m  wide elevator &  g = 9.8 m/s/s  a beam travelling at  300,000 kmps  will fall  5.44 pico mm  (mm^-12)  measured at the far wall,  & the beam angle at the wall (ie the tangent to the curve) will be  0.2235 pico arcsec  (arcsec^-12).   This is a simple ballistic calculation (ie as per Soldner)(ie as per Newton).   For Einsteinian numbers just multiply by 2 (multiplying by 2 is nearnuff & ok at these small angles)(yes i checked).
These small values did not appear to be a concern in 1915, ie when the ability to measure distance & angle was say one millionth of the sensitivity of  2018  instruments.   No one in 1915 pointed out that the curve couldn’t be measured that accurately, not even if u used a  100 m wide elevator & a gravity of  10g  (here u would increase the  mm  & the arcsec by say 100)(at these small angles).   If Einstein & Co could measure a beam to say  0.005 mm at the far wall etc then they would need to magnify their curve by say  10^10  (or if using  100 m &  10g they would need to magnify by say 10^8).
And how would Einstein & Co make a very thin-narrow beam.   Once a slit gets down to say  0.001 mm u get diffraction or something.  And u would need to have two slits, one vertical & one horizontal – ie doubled diffraction.   In fact u would need two sets of slits (ie 4 slits), to establish a fixed initial trajectory  (the source being a big flame or a big element or big something), ie double-double diffraction.   I wanted to get away from much of this sort of complication by simply allowing distant starlight throo a small hole (ie one pair of slits).  But u said no.   So i guess that Einstein & Co cant use starlight either.
Ok, lets say that Einstein & Co manage to get a  0.001 mm beam of light.  The deflection at the far wall is only  0.000,000,000,005,444  mm (ie their beam is  200,000,000  times bigger).  In addition they can measure to only say  0.005 mm or lets make that  0.001 mm  (that is almost  100,000,000,000  times bigger than that deflection).  Here is a draft letter………..
Dear Dr Albert Einstein.
I refer to your recent request for funding to allow u to further develop your  thort-X  illustrating the possible equivalence of the bending of light due to gravity & acceleration in an elevator. 
Please advise how an observer might measure the bending of the beam of light.   The accuracy of today's instruments falls short by a factor of  100,000,000,000.  Furthermore the beam of light should ideally be no more than  0.000,000,01 mm wide.    A beam one photon wide might be acceptable.  In which case we strongly advise that u firstly discover the photon.
From our point of view u are making up total fiction, & we think that your thort-X  will be a waste of money. 
Good luck.
The Institute of Naked Scientists.
PS -- can we keep the nude pix u sent us.

[Halc]

I think that it is ok to insist on non-local inputs. However in the case of my far-away starlight i think that that should be acceptable

Then the task is trivial.  No need to consider photons.  The star is not accelerating with you, so just watch the star and if it seems to accelerate, it is you that is actually accelerating.  Measuring the bending of light is totally unnecessary.

[Halc]

Ok i had a think.

Hope it didn't hurt too much.

I crunched some numbers in Excel. For a 10 m  wide elevator &  g = 9.8 m/s/s  a beam travelling at  300,000 kmps  will fall  5.44 pico mm  (mm^-12)  measured at the far wall,  & the beam angle at the wall (ie the tangent to the curve) will be  0.2235 pico arcsec  (arcsec^-12).   This is a simple ballistic calculation (ie as per Soldner)(ie as per Newton).

OK, but the box falls by the same amount during that time it takes the beam to cross it, so the beam appears to go straight as measured by the observer in the box.

Good luck.
The Institute of Naked Scientists.
PS -- can we keep the nude pix u sent us.

No, the sign-off is: Send us $2500 or we send your porn-watching webcam footage to your entire contact list.  Oh wait, Einstein was way back in the day and his laptop didn't have a webcam...

[mad aetherist (OP)]

I think that it is ok to insist on non-local inputs. However in the case of my far-away starlight i think that that should be acceptable

Then the task is trivial.  No need to consider photons.  The star is not accelerating with you, so just watch the star and if it seems to accelerate, it is you that is actually accelerating.  Measuring the bending of light is totally unnecessary.

If the star is nearby then u could cheat in that way, but i am talking about a distant star, meaning a distant galaxy of course.  Here u could cheat by using that to tell u if any rotation of the elevator (at least in one or two planes)(it couldnt tell u about all 3 planes).
One problem with this star stuff, & with much of the elevator stuff that u read, is that everyone ignores the need to keep the elevator steady, if any rotation or vibration then most bending tests would be hopeless. It might help if u had a super-gyro to keep an eye on the size of any such rotation etc to allow correction of the raw measurements in some instances (depending on the tests).
Even if u used an inboard source of light u would still probly need that sort of correction.
[17dec2018-- I AM FAIRLY CERTAIN THAT EINSTEIN HAD A RAY OF LIGHT ENTERING HORIZONTALLY AT THE MIDDLE OF ONE WALL.]

[mad aetherist (OP)]

I crunched some numbers in Excel. For a 10 m  wide elevator &  g = 9.8 m/s/s  a beam travelling at  300,000 kmps  will fall  5.44 pico mm  (mm^-12)  measured at the far wall,  & the beam angle at the wall (ie the tangent to the curve) will be  0.2235 pico arcsec  (arcsec^-12).   This is a simple ballistic calculation (ie as per Soldner)(ie as per Newton).

OK, but the box falls by the same amount during that time it takes the beam to cross it, so the beam appears to go straight as measured by the observer in the box.
Comment: A straight beam is just as difficult to measure as a curved beam. So all of my comments apply. Re going straight, i will cook up a response to that.

[Halc]

If the star is nearby then u could cheat in that way, but i am talking about a distant star, meaning a distant galaxy of course.  Here u could cheat by using that to tell u if any rotation of the elevator (at least in one or two planes)(it couldnt tell u about all 3 planes).

Rotation is absolute, so I don't need to look out the window to detect rotation.  Rotation is about one axis, not one or more planes.
A super-distant star is functionally the same as a light source bolted to the box.

One problem with this star stuff, & with much of the elevator stuff that u read, is that everyone ignores the need to keep the elevator steady, if any rotation or vibration then most bending tests would be hopeless.

You quoted Einstein's description.  It was a box hanging on a rope that went off into the darkness.  The guy could go outside the box and see the rope.
We can assume a reasonable lack of vibration and spin.  If it spins, the guy can take steps to halt that.  He's got a lab after all.  Yes, that's what gyros do.  You can halt the spin of Earth if you are in possession of a gyro that's up to the task.

[mad aetherist (OP)]

If the star is nearby then u could cheat in that way, but i am talking about a distant star, meaning a distant galaxy of course.  Here u could cheat by using that to tell u if any rotation of the elevator (at least in one or two planes)(it couldnt tell u about all 3 planes).

Rotation is absolute, so I don't need to look out the window to detect rotation.  Rotation is about one axis, not one or more planes.
A super-distant star is functionally the same as a light source bolted to the box.

Yes rotation can be measured inside the elevator. Rotation is about one axis but it is unlikely that that axis coincides with one of the elevator's 3 axis.
A super-distant star is much the same as an internal light, but the photons coming from the distant star will be pointing exactly along that vizible line,  whereas photons coming from an internal source can be crabbing-skidding as they come out (i can explain).
[17dec2018-- I AM FAIRLY CERTAIN THAT EINSTEIN HAD A RAY OF LIGHT ENTERING HORIZONTALLY AT THE MIDDLE OF ONE WALL.]

One problem with this star stuff, & with much of the elevator stuff that u read, is that everyone ignores the need to keep the elevator steady, if any rotation or vibration then most bending tests would be hopeless.

You quoted Einstein's description.  It was a box hanging on a rope that went off into the darkness.  The guy could go outside the box and see the rope.

I havent been able to find Einstein's description for his thort-X for the bending of light in an elevator. The rotation stuff applies mainly to the elevator when out in deep outer space, even if being pulled by a rope. But it must also apply to the elevator when hanging near say Earth, or even if sitting on the surface. 

We can assume a reasonable lack of vibration and spin.  If it spins, the guy can take steps to halt that.  He's got a lab after all.  Yes, that's what gyros do.  You can halt the spin of Earth if you are in possession of a gyro that's up to the task.

Yes but the exact halting of spin or the measuring-correcting for spin must be an even bigger problem than the primary measuring that i detailed.  We are talking about micro micro stuff.  And the main thrust of today's posting is re the practical side of testing & measuring.

[Halc]

the photons coming from the distant star will be pointing exactly along that vizible line,  whereas photons coming from an internal source can be crabbing-skidding as they come out (i can explain).

You say you can, but you don't.
Last I checked, I could not purchase a photon-crab-skidding detector.   You need a security clearance to get one.

[mad aetherist (OP)]

SOME  THORTS  RE  EINSTEIN'S  THORT-X  RE  THE  BENDING  OF  LIGHT  IN  AN  ELEVATOR.

In this posting i want to have a fresh look at the exact nature of the bending of light in an elevator.
I haven’t been able to find a link to Einstein's thort-X  re the bending of light in an elevator  –  i hear that this thort was in  1911.  But it is obvious to me that if an elevator is accelerated upwards at  g  (in zero gravity) then the beam of light crossing the elevator must appear (for an observer in the elevator) to have a bend downwards equal to a ballistic trajectory. 

If the elevator is fixed to the surface of Earth then according to Einstein's  1915  version of GR the bend downwards will be equal to the aforementioned ballistic bending, the GR bending in the elevator being due to the time-dilation half of spacetime.  The other half of  GR bending is the spatial half of spacetime bending & here it is zero because the spatial bending only applies to the radial component of the gravity field, & here in the elevator this component is zero (the gravity field being vertical).   Here we ignore Earth's spin & orbit & the associated centrifugal accelerations (ie for the purpose of the thort-X   Earth is not spinning or orbiting)(& we ignore the Moon).

I daresay that the above is in accord with what Einstein said. The bending due to gravity is numerically equal to the bending due to acceleration & both are numerically equal to the simple ballistic bending (if g is the same in each case).

My understanding of  GR  is that the presence of mass makes time dilate, moreso near the mass, thusly the slower light in the bottom of the beam in the elevator is overtaken by the faster light in the top of the beam, thusly making the beam curve-bend downwards towards the mass.  This is the time portion of spacetime bending.
And the presence of mass makes measuring rods contract in the radial direction from the effective center of mass, but there is no contraction in the tangential direction, & the beam in the elevator is moving in the tangential direction only, hencely is not affected.  Any such bending is the space portion of spacetime bending.

I am not sure that a photon follows a ballistic trajectory near mass.  And i don’t believe in the time-dilation reasoning for that half of the spacetime bending in  GR.  However i think that light is slowed near mass (giving Shapiro Delay).  And i believe that the modern satellite measurements of  1.75 arcsec of bending near the Sun are correct.  I think that there are some unknown reasons for all of this, & the GR reasoning is false, but accidentally gives the correct numerical solution (at least for bending near the Sun). 

Re the bending of light passing the Sun. This bending is the bending that happens to a photon when it comes from infinity, passes the Sun, & reaches Earth.  The mentions of  1.75 arcsec i think refer to the bending that happens when the photon comes from infinity passes the Sun & then goes to infinity -- likewise the  0.875 arcsec for each of the spatial GR bending & the time-dilation GR bending & the ballistic Newtonian bending.  But even tho these three bendings are equal for infinity to infinity they are different along the way, & strictly speaking the three bendings all have a slightly different numerical value at Earth's orbit (ie during eclipse) -- but the differences to the infinity to infinity bendings is trivial.

However in our elevator the strengths of the three bendings have a fixed value for each -- it aint similar to a photon approaching the Sun then passing the Sun then going away from the Sun, where the three strengths & directions change continuously.  The strengths in the elevator are similar to the strengths that we have when the photon is at its nearest to the Sun -- ie all three strengths in both cases are at 90 deg to the photon's trajectory.  For the GR time-dilation bending the strength is at a max -- for the spatial GR bending the strength is zero (because the photon is moving tangentially not radially) -- for the ballistic Newtonian bending the strength is at a max.

For the fourth bending, the acceleration bending in zero gravity field, this is in effect identical to the Newtonian ballistic bending but is due to the elevator going ballistic (in an acceleration field) rather than the photon going ballistic (in a gravity field), so the fourth bending generally doesnt get a special mention.

[mad aetherist (OP)]

Now we come to my version of this thort-X,  an elevator in free-fall.

If there is no gravity field then the elevator will be static.  And we assume that it is not spinning.  The beam of light will go straight across the elevator, ie no bending.

If there is a gravity field then the elevator will accelerate at say  g.   If the gravity field happens to be exactly downwards in the elevator then the beam will bend downwards at a rate equal to the ballistic bending.  However the observer & elevator will fall at the same rate as the beam, hencely the beam will appear to go straight.
Here i am talking about the GR version, where the bending (in the elevator here) is due to time-dilation, which happens to be numerically equal to the ballistic bending.

Therefore the beam will appear to go straight when the elevator is in a gravity field & when not.  The only difference tween the two is that if there is a gravity field then the photon will not point exactly along the line of the beam, it will point downwards a little as it crosses the elevator,  the angle being at a max when it gets to the far wall.  To the observer the photon will appear to crab, ie skid sideways.  But the photon will in fact be propagating directly ahead in its own frame, ie as if following a simple curved trajectory.

So in theory it might be possible to measure the downwards angle.   However the problem is that the downwards angle of such a photon is certainly much too small to measure -- & in any case i don’t even know of any kind of test that might measure such an angle.   It’s a completely new area.  Still thinking.

At this point i wish to advise that i dont agree with the above GR analysis. I think that for accidental reasons the  0.875 arcsec of bending near the Sun due to time dilation is equal to the 0.875 arcsec of bending due to radial length contraction both of which are equal to the 0.875 arcsec of bending calculated for a simple ballistic trajectory.  In fact i think that there is no such thing as bending due to time dilation nor radial length contraction, both are false.  I think that there is bending equal to a simple ballistic bending, & in addition an equal extra dose of bending due to the slowing of light near mass.  The slowing of light near mass is due to photaeno drag, which i wont go into here (i mention it in another  thread).
Now, the ballistic bending & the bending due to drag might be equal for a beam passing the Sun, but they are unlikely to be equal for a beam crossing our elevator.  The result is i think that the bending in the elevator due to free-fall in a gravity field will not be a straight line, there will be bend (i am not sure how big)(it will be small)(still thinking).  Anyhow, if so, then that would allow an easier way to tell, ie measuring a bend has to be easier than measuring the photon downwards angle.

[Halc]

But it is obvious to me that if an elevator is accelerated upwards at  g  (in zero gravity) then the beam of light crossing the elevator must appear (for an observer in the elevator) to have a bend downwards equal to a ballistic trajectory. 

Careful of things you find 'obvious', but yes in this case.  Ditto for the one sitting on the surface of Earth.
The straight-across observation was for the freefall case, both in and not in a gravitational field.

[Halc]

Therefore the beam will appear to go straight when the elevator is in a gravity field & when not.

So says the 'silly' equivalence principle, yes.

To the observer the photon will appear to crab, ie skid sideways.  But the photon will in fact be propagating directly ahead in its own frame, ie as if following a simple curved trajectory.

So far you have failed to say how this can be measured.  If you like, make the gravity and distance large, so the 'crabbing' is significant.

So in theory it might be possible to measure the downwards angle.[/b]   However the problem is that the downwards angle of such a photon is certainly much too small to measure -- & in any case i don’t even know of any kind of test that might measure such an angle.

It would I suppose help if there was such a thing.

[mad aetherist (OP)]

WHAT  CAN  AN  ELEVATOR  THORT-X  TELL US ?
A thort-X  can be a good illustration of an idea, but it can never prove anything.  Proof can only be approached by tests-measurements-experiments.  It seems that Einstein was happy in 1911 to spout that bending of light in an elevator would be seen to be identical for when the elevator was accelerating upwards at  g  in zero gravity compared to when it was stationary in a gravity field of strength  g.   Yet in  1915  in his  GR  he decided to add that in a gravity field there was an additional bending due to length contraction in the radial direction due to gravity potential near mass.   But not a word about his original spouting about his  1911 elevator equivalence of bending. 

Einstein could have pointed out that his  1911 spouting was not affected because the radial length contraction in the elevator was zero because the gravity field is at 90 deg to the beam (& the cosine of 90 deg is zero).  That would be correct numerically, but it wouldn’t be ok reputation wise – the excuse would hold up in court, but nonetheless it was morally a disaster.  So Einstein decided to ignore the whole elevator bending of light stuff after that  (hey everyone, look over there, it’s a blackhole).

Suddenly in  1915  Einstein had managed to prove that thort-Xs  are not as good as might be thort. 
How can acceleration & gravity in  1911  be equivalent if in  1915  u find that gravity includes a new major effect.   Thort-Xs would never be the same again.  Up till then u could virtually get a Nobel for a good thort-X, but no more. 
Of course the usual thing happened.  Einsteinian apologists over the years came up with all manner of excuses that acceleration  g  definitely involves a characteristic  that mimics  gravity g.  Apologists in SR & in GR have an almost endless menu of relativistic tricks.  They can with ease show that in an accelerated elevator clocks near the floor tick slower than clocks near the ceiling, just as if the elevator were sitting a gravity field.  Amazing stuff.

U can draw a matrix of their stupid excuses. They can play with time-dilation & length contraction & relativistic mass.  They can invoke observers sitting in all sorts of places, inside, outside, far away, moving, sitting, jumping.  The effect can be real or it can be perceived-apparent.  They can talk of individual photons when it helps them, but mainly they ignore photons & anything micro & invoke macro things like waves & wave-fronts & beams & rays.

Their arguments & proofs usually have one or two direct or indirect circular references to the issues in question, eg they will use  GR to help explain  GR, eg they will use an elevator thort-X to help establish GR, & then use GR to help excuse a problem with the elevator thort-X. 
Even better, they have no hesitation in invoking arguments that directly contradict  SR  or GR, or thems postulates & principles & laws.  It all comes naturally  (hey, look over there, it’s a gravity wave).

[mad aetherist (OP)]

But it is obvious to me that if an elevator is accelerated upwards at  g  (in zero gravity) then the beam of light crossing the elevator must appear (for an observer in the elevator) to have a bend downwards equal to a ballistic trajectory. 

Careful of things you find 'obvious', but yes in this case.  Ditto for the one sitting on the surface of Earth.
The straight-across observation was for the freefall case, both in and not in a gravitational field.

Yes obvious aint necessarily obvious.  I do believe in relativity, neo Lorentz relativity, not Einsteinian SR & GR relativity (altho in many cases they give the same answer).  So i am comfortable with using gamma to show that the apparent whatever aint the same as the true whatever.  This applies to ticking & length.  But when inputting V into gamma i use absolute relative velocity (the velocity of the aetherwind), not the Einsteinian relative velocity.  But when Brown measures the angle of the two pendulums (wts on threads) then in a gravity field if he uses a measuring rod horizontally then the length of the rod will not be affected by its height from the floor because the rod is being held perpendicularly to the line of action of the field, Einsteinians & aetherists agree.  But ticking is almost certainly slower near the floor (in a gravity field) -- but i am not sure how that might affect Brown's measurement of parallel.  In #7 set fair i think alluded to this. I answered in #13.  Ticking might affect our perception of mass & of  N & of  g etc.  So anyhow yes obvious aint necessarily obvious.

[mad aetherist (OP)]

Therefore the beam will appear to go straight when the elevator is in a gravity field & when not.

So says the 'silly' equivalence principle, yes.

I think that there are a few 'the' equivalence principles.
The primary one is i think the law of the equivalence of inert mass & gravity mass (as per Einstein's chest thort-X).
The next one is say the weak equivalence principle, that all things fall at the same speed.
The next one is say that all experiments will give the same equivalent result in any-every reference frame.
And we are mainly talking here re the equivalence of bending of light in an accelerated frame & in a gravity field.
18dec2018: There is a 5th equivalence -- equivalence is the name given to the accidental result that someone gets the correct number using the wrong reasons (or the correct equation using the wrong logic). Einstein's SR & GR are full of this stuff, or they would be if they in fact gave the correct results (SR & GR are rarely accurate)(as we are now finding in our modern accurate world)

To the observer the photon will appear to crab, ie skid sideways.  But the photon will in fact be propagating directly ahead in its own frame, ie as if following a simple curved trajectory.

So far you have failed to say how this can be measured.  If you like, make the gravity and distance large, so the 'crabbing' is significant.

I will talk about this later today.

So in theory it might be possible to measure the downwards angle.[/b]   However the problem is that the downwards angle of such a photon is certainly much too small to measure -- & in any case i don’t even know of any kind of test that might measure such an angle.

It would I suppose help if there was such a thing.

Modern science seems to have ignored photons.  There is little official info re how long or wide etc a photon is or isnt. Are photons dead straight.  When they propagate along a curved-bent beam do individual photons bend internally or do they remain straight.  Later today i hope to describe a test re measuring-detecting the downwards angle (crabbing angle).

[Halc]

I do believe in relativity, neo Lorentz relativity, not Einsteinian SR & GR relativity (altho in many cases they give the same answer).

In all cases they give the same empirical answer.  If they didn't, there would be a falsification test.  Your aether theory on the other hand does not.

But when Brown measures the angle of the two pendulums (wts on threads) then in a gravity field if he uses a measuring rod horizontally then the length of the rod will not be affected by its height from the floor because the rod is being held perpendicularly to the line of action of the field, Einsteinians & aetherists agree.

I don't think orientation in a gravitational field has any effect on length of a rod in its own frame.

[Halc]

So says the 'silly' equivalence principle, yes.

I think that there are a few 'the' equivalence principles.
The primary one is i think the law of the equivalence of inert mass & gravity mass (as per Einstein's chest thort-X).
The next one is say the weak equivalence principle, that all things fall at the same speed.
The next one is say that all experiments will give the same equivalent result in any-every reference frame.

None of those.  I means the one that comes up when you google "equivalence principle".
The inertial thing is a corollary of it.
Things do not fall at the same speed, but rather accelerate identically under an identical gravitational field.
Not all experiments yield the same result in different frames.

Modern science seems to have ignored photons.  There is little official info re how long or wide etc a photon is or isnt. Are photons dead straight.

No, photons are quantum entities and do not have classic properties such as dimensions, straightness, or even location.