The thought experiment depicted in the drawing on the left
deals with simultaneity. A space ship is moving at a high velocity
from left to right. According to relativity speed of light should be
constant for the observer within the ship as well as the
stationary observer on the ground.
Light rays sent simultaneously from the front and back of the
ship will meet in the center of the ship for the observer within the
ship. While for the non moving observer on the ground the light
pulses should meet more towards the back of the ship.
This information could be used to set up an experiment so that
a cat is shot by a gun if the rays of light do not meet in the
center. (lucky for the cat).
So for the observer in the ship the light rays meet in the center
so the cat should be alive while for the observer on the ground
the cat should be dead as the light rays do not meet in the
Now which point of view is correct. Is the cat alive or dead?
One way of solving this problem would be to say that the firing
mechanism will obey the laws within the moving ship so the cat
will be alive. This off course means that point of view of the non
moving observer on the ground is superfluous. This point is
clearly shown to be correct by photon acceleration caused by
moving plasmas showing that simultaneity is preserved.
The above argument based on lack of simultaneity is in my view is incorrect as moving objects curve space and light is carried forward in curved
space so that the point of view of observer moving with space ship is correct. This point is clearly shown to be correct by photon accleration
caused by moving plasma.