errandir said:

Xgen said:

... lets return to the PASD figure that i posted before. If we have not absorbing but reflecting plates and measure the time both photon reach again the middle point it is obvious that they will return at the same time.

It is obvious to me that this is true in the rest frame of the PASD, but that this is false in any frame that is moving WRT the PASD in the same direction.

I just wanted to say that my respons to this was stupid. It is obvious that they will return at the same time in any inertial frame. I agree with you.

I am reading through your post, Xgen, and will respond when I figure out what you are saying.

Xgen said:

If the device is on a inertial frame of reference moving with a velocity v according to the absolute space, they will be absorbed at different times but if they was reflected they **will reach the middle point S at the same time, so if there is an observer there he will see both events as simultaneous**.

I agree with this (now). I was being stupid earlier.

Xgen said:

MM experiment had not been directed at detecting time-shifts but measurement of velocity of light. They had though that velocity in the direction of movement would be c+v and opposite to it c-v.

Actually, the velocity of light was accepted as some round-about value, and they <i>were</i> trying to detect time-shifts (well, equivalently, they were trying to detect phase shifts indirectly by determining the shift in a fringe pattern). You are forgetting about the perpendicular leg of the apparatus.

Consider this simple algebraic example that presumes an ether:

L is the length of the leg in question

c is some value (with dimensions of speed) that is assumed >> v

v is the speed of the apparatus WRT the ether

θ is the angle that the leg in question makes with the direction of motion through the ether

t is the round-trip time of flight of the light in the leg

t = (2L/c)[1-(v/c)<sup>2</sup>cos<sup>2</sup>θ]

So, for two legs perpendicular to each other, the time of flight difference Δt is:

Δt = t<sub>2</sub> - t<sub>1</sub> = (2L<sub>2</sub>/c)[1-(v/c)<sup>2</sup>cos<sup>2</sup>θ<sub>2</sub>] - (2L<sub>1</sub>/c)[1-(v/c)<sup>2</sup>cos<sup>2</sup>θ<sub>1</sub>]

Assuming for the time being that L is invariant and equal for both legs and that the legs are perpendicular gives:

Δt = (2L/c){[1-(v/c)<sup>2</sup>cos<sup>2</sup>θ] - [1-(v/c)<sup>2</sup>cos<sup>2</sup>(θ + π/2)]} = (2L/c){[1-(v/c)<sup>2</sup>cos<sup>2</sup>θ] - [1-(v/c)<sup>2</sup>sin<sup>2</sup>θ]}

This can be pushed around to show that some sin<sup>2</sup> + cos<sup>2</sup> = 1, but, ultimately, a dependence on θ remains. This is precisely what Michelson and Morley used as a theoretical basis for comparison. They rotated there apparatus 360<sup>o</sup> and performed the experiment at different times of the day and in different seasons. They recieved a null result. The experiment was performed several more times with a trend in increasing accuracy and a correlated certainty of the null result. Of course, if you know your history of late 19th century science, you know that Lorentz proposed a seemingly reasonable suggestion that would save the ether. Well, that's another story.

Xgen said:

Their interfometer is very inpractical for the measurement of the time-shifts that PASD measure, becose interference happens when two waves overlaps, or sayed in another words when are in the same place at the same time. This means that both photons should be also putted in the same place at the same time. But this make functioning of entire device senseless.

I think considering light in terms of photons makes this device impractical/senseless from the start. This device relies on the wave nature of light and disregards the particle nature. Is this a reason why you have a problem with the device?

Xgen said:

Something more. All the calculations that should be made with PASD should be localy-distributed. What that means. ...

Yes, I believe I see what you're saying, and I totally agree with you on this point. I would certainly be interested in the results of your experiment. It seems that it is a quite reasonable one to conduct at the current stage of technology, and I wonder if it has not already been done. Have you done a literature search?

Xgen said:

I see that you are perplexed how a frame of reference can move with the speed of light.

Not exactly. I just don't think that any frame of reference <i>relevant to the PASD</i> can be such a frame. I have already explained why I feel this way.

Xgen said:

Well, accualy I can prove that if space and time steps are taken small enough everything moves with the speed of light, even massive particles. Mass is a global concept, in microworld this concept has lower-limit for application (take Heizenberg inequality if you like).

You can <i>prove</i> it? I don't see how an <i>interpretation</i> of the HUP proves anything, much less that everything moves at the speed of light or any other speed for that matter. I am no expert in QM, though, so, perhaps you would be willing to help me out with this?