Sagnac optical rotation

[AntonioLao]

Sagnac
In 1913, Georges Sagnac, a French physicist, discovered that light can be used to measure rotation (similar experiments were performed earlier in 1911 by Harress). He demonstrated the existence of differential time. That is to say the time needed by light to go around a circular path differs where and when the path or the observer is fixed or is rotating. In the language of electromagnetic waves propagations this differential time is translated into a principle of phase shift. The same principle was used by Michelson and Morley for locating the ether’s rest frame of reference in 1887. In 1905 this null experiment became the basis for Einstein’s first principle of special relativity that the speed of light is a constant in all inertial frames of reference moving at constant velocities with respect to each other.

On the other hand, for accelerated frames of reference, for example, rotating frames, the phase shifts are clearly detected. Since the invention of the laser, Sagnac optical rotation is applied for the construction of laser gyroscopes use in extremely high speed navigation systems. The extreme sensitivities are now used for more advanced rediscovery of the ether’s rest frame inside a gravito-magnetic probe and further validate or invalidate Einstein’s general relativity http://adsabs.harvard.edu/abs/2008arXiv0802.3346B.

[mkirkpatrick]

A most interesting thread starter my friend,causing one to wonder as to the rotation of Ying and Yang,what speed would they be spinning at? Light speed? Or even at the
speed of lifeful expression?



regards michael.

[AntonioLao]

Reaching light speed is still an engineering problem. In Sagnac ring laser gyroscopes the lights traveling in opposite direction counterclockwise and clockwise arrived at different time if the rings are rotating not at lightspeed but the lights are.