Ok, while i still processing this, the following questions emerged :
"It is clear that two events that are simultaneous in frame S (satisfying Δt = 0), are not necessarily simultaneous in another inertial frame S′ (satisfying Δt′ = 0). Only if these events are colocal in frame S (satisfying Δx = 0), will they be simultaneous in another frame S′."
That takes the assumption, that gravity isn't absolute spacetime.
http://library.thinkquest.org/C0116043/specialtheorytext.htm
That takes the assumption, that not just local time, not just a ruler's size, but distance itself is dependant on light.Is there any experiment, that invalidates, that gravity is absolute spacetime?
http://vixra.org/pdf/1110.0037v1.pdf
That says the working of GPS shows that c is constant in the frame of gravity field.
Not constant to everything that moves. (Like Earth's surface. MM experiment doesn't showed Earth's rotation due to the length contradiction of the interferometer's arm.)
What do theese calculations say about the following dilemma i read : there is a fast moving train, observer A on the train, observer B is on the ground.
You light two bulbs at the begin and end of the train.
Is it possible, that both A and B see both lights at the same time?