# One-Way Speed of Light

Another make it or break it experiment for TOEBI is the following one-way speed of light experiment. Measuring the one-way speed of light won’t be as trivial as one might initially think, check out the Wikipedia article for more information.

My claim, based on TOEBI, is that the one-way speed of light won’t be the same in all inertial frames and to my surprise the following experiment has never been done.

Let’s have a train (our inertial frame) moving with a constant velocity $\vec{v}$. Then we set up two light detectors, say 30 meters apart and mark up the spot X in between the detectors having an equal distance (15 m) to the detectors. At spot X we synchronize two atomic clocks and move them next to the detectors with the same, very slow, pace. Detector and atomic clock pair functions so that when light is detected then atomic clock records the time of the event.

Then we set up our light source on spot X and start making events. According to relativity theories those recorded times should be exactly the same, but according to TOEBI that won’t be the case. How come? That’s because photons move through FTE, in our case, FTE provided by Earth. Inside FTE, photons move at speed $c$ as expected but the problem obviously arises in our experiment. If the train moves at speed $v$ and photons at speed $c$ then photons will reach the rear detector sooner than the front detector, but Einstein disagrees, without any experimental backup.

Synchronization of the atomic clocks was performed as relativity theories would require in order to keep those clocks synchronized. In reality, it would be sufficient to put all those equipment in their proper places before the train leaves a station. Acceleration of the train won’t unsync those clocks even though equivalence principle “dictates” so, once again, no proof exists for unsynchronization in case like this one (a.k.a. acceleration happens perpendicularly to a gravitational field).