Equivalence

[xelasnave]

I am not sure of the theory but thinking about it and looking at a site something stood out that I thought I would ask about here.

In the lift experiment..where a beam of light is shone from a stationary lift thru a lift passing by ..in he drawings I have seen they show the beam of light in the moving lift to be bent..or curved..I have looked at this for ages and say that the only way the light beam could be bent this way is if the acceleration of the moving lift varied as the light beam went thru..otherwise all that the person in the lift could observe would be a straight beam...
is anyone with me here and do you think the representation of a bent beam is correct or something a human mind has invented because it can not comprehend the situation

alex

[dannat (Daniel)]

I think it could be correct - it comes back to the point about light not being a particle but a wave - it is like the single slit experiment - shoot light thru a strip and you get a single beam on the other side, but shoot it thru two slits and you get a pattern which does not seemit could result. there is a yuotube video explaining - will try & find it

[ngcles]

Hi Alex,

Well, I think I'm with you on this one.

Aside from relativistic considerations (and motion of the observer -- let's assume he/she is static), the light (well each individual photon) has to travel in a straight line from the origin, don't it?

Assuming it is a reasonably well focused torch beam (better a laser) (but not shining at a plane) they would all be travelling in more or less the same direction at exactly the same speed, so logic say's it must be a straight line I guess?

Best,

Les D
Contributing Editor
AS&T

[skwinty (Steve)]

Hi Alex
It all depends on who is making the observation.
The person in the static lift or the person in the moving lift.
One event and two realities.
The person in the static lift should see the apparent curvature of the light beam as the moving lift has moved as the beam travelled along and doesnt land on the exact opposite position of the far wall.

[xelasnave]

Originally Posted by skwinty

Hi Alex
It all depends on who is making the observation.
The person in the static lift or the person in the moving lift.
One event and two realities.
The person in the static lift should see the apparent curvature of the light beam as the moving lift has moved as the beam travelled along and doesnt land on the exact opposite position of the far wall.

My point is that one can only see the light as a straight beam .. I took the time to draw a step by step progression of the lift ...the beam can only be straight so the moving lift can only ever pass a straight beam...no matter how you see it in the lift it can only scribe a straight path..that is why I wondered how the diagram showed their beam as bent...there is no way that can be correct...unless the acceleration is varied...

From this also I reckon that one can work out ones speed relative to the source of the light by taking the angle that the straight beam of light appears to travel thru the moving lift.
An angle of 45 degrees indicates it passed at C I think... I have not worked out the angles at various fractions of C but obviously at slower speeds the angles will be less ...

What would be interesting is if we did the double slit experiment to the beam ..where would the wave pattens appear on the opposite wall??? either side of where the light beam passed I wonder or entirely to the bottom side..I have no idea but it would be neat to speculate... I have not yet done so.
alex

[sjastro]

Your description sounds like the geometrical interpretation for time dilation in special relativity except that light beam in the stationary elevator has to bounce off a mirror back to the light source. The observer in the stationary elevator will see the light beam as a straight line.

The observer in the passing elevator will see the light beam travel on an oblique pathway between the light source and mirror. How oblique the pathway, is proportional to the speed of the elevator.

If the laws of physics are broken and the elevator was able to travel at the speed of light(???), the observer in the moving elevator will see the direction of the light beam as being in the same direction as the movement of the elevator. This of course would be perpendicular to the direction as seen by the stationary observer.

Regards

Steven
http://users.westconnect.com.au/~sjastro/small

[netwolf]

Hi Alex,

This was what got me into Science big time, a book called "Relativity and Commonsense" was my first intro to this Principal.
Perhaps this link might explain it better.
http://www.newtonphysics.on.ca/EINSTEIN/Chapter10.html

Regards
Fahim

[sjastro]

Originally Posted by netwolf

Hi Alex,

This was what got me into Science big time, a book called "Relativity and Commonsense" was my first intro to this Principal.
Perhaps this link might explain it better.
http://www.newtonphysics.on.ca/EINSTEIN/Chapter10.html

Regards
Fahim

The link is like Swiss cheese, it's full of holes.

Regards

Steven

[xelasnave]

Thank you Steven and thank you Fahim.

Well that site has a straight path and a curved path covered and I am happy with my current understanding..I think

What does bother me is the principle itself... unless I have it incorrect acceleration is related to gravity so as to express it in a force humans can understand but in doing so we let "time" creep into the mix.. I can not see why it is there..its relevance is only so humans can relate the magnitude of the "force" ..er which is not a force by the way and without it how different will general relativity be then???

I have yet to actually see the 10 field equations..not that it will do much good as I may as well be reading Chinese..I must have seen them at least once someplace by now one would think ..but I can not recall...

As to gravitational lensing... it happens but not the way the mags show it..using the ball and the blanket mentality leaves one misinterpreting it... one day I will post the truth (my version) with some diagrams that will prove my point.
alex

[skwinty (Steve)]

Originally Posted by sjastro

The link is like Swiss cheese, it's full of holes.

Regards

Steven

The professors own words. Dr Paul Marmet

"
As you know, I am retired from the physics department of the university of Ottawa. However, during the last three years, I still had an office at the university, as a voluntary professor, because I was the supervisor of a graduate student (completing his Ph. D. in electron spectroscopy). A few months ago, he completed his degree and I have been ordered to leave my office at the university. The head of the department explained that it was because I keep questioning the fundamental principles of physics. The exact words were: "Ton problème est que tu remets en question les principes fondamentaux de la physique".
I cannot stop doing it.
I am now working full time at home. "

[sjastro]

Originally Posted by xelasnave

Thank you Steven and thank you Fahim.

Well that site has a straight path and a curved path covered and I am happy with my current understanding..I think

What does bother me is the principle itself... unless I have it incorrect acceleration is related to gravity so as to express it in a force humans can understand but in doing so we let "time" creep into the mix.. I can not see why it is there..its relevance is only so humans can relate the magnitude of the "force" ..er which is not a force by the way and without it how different will general relativity be then???

The author is trying to use gravitational redshift calculations to debunk equivalence. What it means is that a clock will run slower in a higher gravitational potential compared to a lower state.

There is a serious problem using this argument.
Gravitational redshift is a direct consequence of the principle of equivalence. You can't use gravitational redshift as a counterargument against equivalence. If equivalence doesn't exist neither does gravitational redshift.
The author also doesn't appear to realise that the gravitational red shift is a function of the rest mass or inertial mass, not the relativistic mass.

Originally Posted by xelasnave

I have yet to actually see the 10 field equations..not that it will do much good as I may as well be reading Chinese..I must have seen them at least once someplace by now one would think ..but I can not recall...

alex

Not only have I seen the equations but had to derive them as part of my Applied Maths degree.

Originally there were 256 equations but with zero solutions, symmetry requirements etc, it came down to an even ten.

Regards

Steven
http://users.westconnect.com.au/~sjastro/small

[sjastro]

Originally Posted by skwinty

The professors own words. Dr Paul Marmet

"
As you know, I am retired from the physics department of the university of Ottawa. However, during the last three years, I still had an office at the university, as a voluntary professor, because I was the supervisor of a graduate student (completing his Ph. D. in electron spectroscopy). A few months ago, he completed his degree and I have been ordered to leave my office at the university. The head of the department explained that it was because I keep questioning the fundamental principles of physics. The exact words were: "Ton problème est que tu remets en question les principes fondamentaux de la physique".
I cannot stop doing it.
I am now working full time at home. "

I feel sorry for the graduate student.

Regards

Steven

[DJDD]

Originally Posted by sjastro

I feel sorry for the graduate student.

Regards

Steven

but the professor could have been a gun in electron spectroscopy...

[xelasnave]

Originally Posted by sjastro

The author is trying to use gravitational redshift calculations to debunk equivalence. What it means is that a clock will run slower in a higher gravitational potential compared to a lower state.

There is a serious problem using this argument.
Gravitational redshift is a direct consequence of the principle of equivalence. You can't use gravitational redshift as a counterargument against equivalence. If equivalence doesn't exist neither does gravitational redshift.
The author also doesn't appear to realise that the gravitational red shift is a function of the rest mass or inertial mass, not the relativistic mass.



Not only have I seen the equations but had to derive them as part of my Applied Maths degree.

Originally there were 256 equations but with zero solutions, symmetry requirements etc, it came down to an even ten.

Regards

Steven
http://users.westconnect.com.au/~sjastro/small

One question ...am I the author to whom you refer???

I don't understand so much of this stuff all I can say is I appreciate all the folk who tolerate my ideas... on the positive it keeps me going..a road I will never find the end to...

alex

[sjastro]

Originally Posted by xelasnave

One question ...am I the author to whom you refer???

I don't understand so much of this stuff all I can say is I appreciate all the folk who tolerate my ideas... on the positive it keeps me going..a road I will never find the end to...

alex

Sorry for the confusion Alex. I was referring to Dr Paul Marmet who came up with this highly questionable stuff.
http://www.newtonphysics.on.ca/EINSTEIN/Chapter10.html

Regards

Steven

[renormalised (Carl)]

Originally Posted by DJDD

but the professor could have been a gun in electron spectroscopy...

Yep, an electron gun

[renormalised (Carl)]

Originally Posted by sjastro

I feel sorry for the graduate student.

Regards

Steven

Problem is, Steve, if you don't keep questioning those principles, no matter how fundamental they are, you're in danger of stopping learning and acquiring knowledge. You may turn out to be wrong in the long run, but science is about questioning. Remember, Newton's laws were fundamental for a very long time, but Einstein and others came along and modified them because they ultimately were incomplete in their explanations of the nature of reality (whatever reality really is, if it even is "real").

[DJDD]

Originally Posted by renormalised

Yep, an electron gun

boom boom!

puns are flying thick and fast here...

[sjastro]

Originally Posted by renormalised

Problem is, Steve, if you don't keep questioning those principles, no matter how fundamental they are, you're in danger of stopping learning and acquiring knowledge. You may turn out to be wrong in the long run, but science is about questioning. Remember, Newton's laws were fundamental for a very long time, but Einstein and others came along and modified them because they ultimately were incomplete in their explanations of the nature of reality (whatever reality really is, if it even is "real").

Yes that is possible, but one aspect that remains a constant is simple logic.

As I mentioned in a previous post, the author uses gravitational red shift calculations to debunk equivalence. Now gravitational red shift is a direct consequence of equivalence. You can't have it both ways or pick or choose aspects of equivalence that conveniently fall in line in forming an argument.

Regards

Steven

[renormalised (Carl)]

Originally Posted by sjastro

Yes that is possible, but one aspect that remains a constant is simple logic.

As I mentioned in a previous post, the author uses gravitational red shift calculations to debunk equivalence. Now gravitational red shift is a direct consequence of equivalence. You can't have it both ways or pick or choose aspects of equivalence that conveniently fall in line in forming an argument.

Regards

Steven

All true.... you can't have your cake and eat it too. Logic would determine that you either have one particular outcome or another. Observation and/or experiment would be the determining factor and unless outcomes change, then you're stuck with what you've got. Doesn't mean it won't or can't change, but that you have a set of outcomes that you should stick to until something changes them down track. However, you can speculate.... the old "thought experiment".