I think you can see that MD thinks that the light sphere moves out from the point at which it was emitted in 'absolute' space and his box is moving relative to 'absolute' space so the light sphere intersects the back wall before it intersects the front wall. This is what the picture is showing. I will not use the term reference frame if you like, it does not matter. Hopefully, you can agree up to this point.
Yes.
So the faster the 'absolute' velocity of the box the shorter time it takes for the light sphere intersect the back wall and the longer time it takes for the light to intersect the front wall.
Correct.
Now let's assume that the box is moving at an 'absolute' velocity of just under the speed of light, say 299,792,457.9 m/s. So you are in the middle of the box and you turn on the light and watch the light creep forward in the direction of travel and almost instantly intersect the back wall.
I'm with to here.
You decide that you want to measure the speed of light so you walk ahead of the creeping light sphere and place a meter stick on the ground and when the light touches the meter stick you start a stop watch when when the light touches the 10 cm mark you stop the watch and low and behold the time on the watch is 1 second so the speed of light is 10 cm/sec as you measured it in the box.
Is the meter stick something you introduced or is it a tool that MD has introduced and used to measure the distance light travels. Is the stopwatch also MD's or is he using the distance light travels from the origin to the edges of the box to determine the length of time the light sphere has been expanding when it intersects the edges of the box?
This is how it would work for MDs universe. Hopefully, you can see that this is an accurate concequence of his belief, if you cannot, well sorry that is the best I can do.
If the questions I have asked have been addressed by MD and you, and he agrees and can confirm he uses a meter stick and a stopwatch as you are using them, then I will have to agree, that the creeping light sphere would not be measured at the speed of light, falsifying the theory. But I don't think he will confirm the tools you are bringing in.
However, I think MD is saying where the edge of the light sphere would be at various times as measured from the point of origin and using light itself as the measuring stick. So when you try to measure the creeping light in your example, you are making a measurement from a moving position in space that he is not making, and you are (might be) using tools he is not introducing, but you are.
The measurement that he is making, i.e, the size of the light sphere as measured from the point of origin, places the wave front of the sphere precisely, and he is just diagramming the box relative to where he calculates the edge of the sphere from the point of origin. The placement of the box can be made to represent any velocity of the box he wants, but he is never measuring the wave front like you are. I'm sure he couldn't even detect the wave front when traveling at ~99.999% of the speed of light, but he can calculate where it would be, even from a box moving at so near the speed of light because he is determining where the wave front, which always travels at the speed of light, would have to be given the point of origin.
He says that if you are in the box, and the box is moving at 99.999% of the speed of light, you would have to establish that point as a new origin and emit a new light, and he says that light will travel at the same invariant velocity from its point of origin and you would measure it from the relativistically moving box to be equal to the invariant speed of light.
Now take a minute and think of the scenario as I interpret it before you go off half cocked.
Then read this:
There is some added complexity if you use your device to measure the speed of light of the wave front of the original sphere. When you are traveling so close to the speed of light as it passes, your meter stick will have to be adjusted (shortened) by what, ~99.999%. Assuming your clock is traveling with you, you will have to adjust for the clock running ~99.999% slower. If you make those adjustments you should come up with the invariant speed of light when you measure the velocity of the first sphere.
I am sure you noticed it is difficult to get a clear concise answer out of MD on this velocity issue - like I said earlier I think he can see his idea does not conform to measurements so himing and hawing.
When I say MD is wrong I do not mean that he is wrong theoretically, I mean that he is wrong because the speed of light quite simply does not show a different relative speed due to the motion of the person doing the measurements or the speed of the light source, and he says it does - wrong.
That may well be the conclusion. Address my questions and my view of what MD is saying and let me respond after you do that.