perhaps not. how could you have relativistic effects of gravity where here is none of it? ? The center line should not be shown to go down ( back in time*) but back up to a point at the normal level, a point, where no time dilation from the general value could be recorded. It is the illustration that needs amending to satisfy the question where really is the most gravity measurable, in or out, * from the "ALMA" thread in alternate theories.