Sagnac Linear Motion Experiment

Sagnac Linear Motion Experiment

Our Goal

Verify a Fundamental Property of Light.

In 1913 Georges Sagnac a French physicist said that one of the key concepts of Einstein’s theory of Special Relativity is false. And he performed an experiment to prove it. The concept is that the speed of light is constant even if the source of light is moving relative to the receiver. A.A. Michelson said, :… relativity gives the velocity of light a still greater importance, since one of its fundamental postulates is the constancy of this velocity under all possible conditions.”

So an experiment proving that the speed of light does change with the speed of the source would require any honest researcher to admit that one of the fundamental postulates of the theory of relativity is false. Thus it should not be used as a reliable explanation of physical reality.

The 1913 Sagnac findings are discounted by the proponents of Einstein as merely an “effect” because it is only valid in movement which is rotational or accelerating. They claim Sagnac’s findings would not be found if the movement of the light source was linear and constant.

Today’s ring laser gyros split laser light into 2 beams and send each beam in opposite directions around a circle. The path of the light is formed with fiber optic cable. They are called a fiber optic gyro or FOG. The time travel difference between the two beams gives a very exact measurement of the motion of the apparatus. In this is a simplified diagram of a FOG if the entire assembly rotates it replicates the 1913 Sagnac experiment.

In 2003 a team of researchers headed by Yi Zheng at St. Cloud University, Minnesota, US (see footnote below) performed a test to determine if Sagnac was right. They modified a fiber optic gyro to test if the time travel difference detected in a circular path would also be present in a linear path.

Then the fiber optic gyro was modified to insert a length of straight fiber cable and the assembly was not rotated but was put on a conveyor. The figures above are from the article published by the Zheng et al.

The 2003 experiment did indicate that there is a time travel change in linear motion paths. Yi Zheng has been a professor at St Cloud university for 30 years. Their findings indicated that the circular or liner path made no difference. In all cases the change in time for light to travel from source to receiver or the change in the speed of light equals 2 times the speed of the source times the change in the path length divided by the standard speed of light squared.

Δt = 2vΔl/c2

v is the speed of the source and l is the length of the path.

Of interest here is that this experiment proved the theory of relativity is flawed, or just wrong. But it is natural to understand why Dr. Zheng did not overtly state that Einstein was wrong.

FECORE has contacted Professor Yi Zheng and he has offed to answer any questions we have and has encouraged us to replicate his work or modify it for added data. He is still teaching at St. Cloud.

So why should this be repeated?

The purpose of FECORE is to do research and publish results that those in the mainstream can not publish because their employers would disapprove. As this information is verified these numbers can be used as a basis for correct interpretation of observations in physics and astronomy because our present analysis is flawed.

What are the costs?

Fizoptika of Malta has an open loop system with 100 m of fiber for $1240. This system would readily lend itself to modification. The company has communicated with FECORE  and the unit is in stock. They can ship it to Europe or the US.

KVH a FOG manufacturer of navigation systems for government and private use says it costs $1000 to manufacture a one axis FOG and they sell a marine FOG for private boats for $3000.
So the Fizoptika product sounds very well priced.

Added to the FOG price would be the conveyor system which is not highly technical but would require a motor which can be operated at precisely set speeds.
A rough estimate is less than $10,000 for the materials and parts.


  1. Zheng, Yi; Yao, Aiping; Wang, Ruyong; and Langley, Dean, “Modified Sagnac experiment for measuring travel-time difference
    between counter-propagating light beams in a uniformly moving fiber” (2003). Electrical and Computer Engineering Faculty
    Publications. Paper 3.

Posted on

January 31, 2018

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