Thanks for your reply.
I wouldnít expect a non-interfering apparatus to affect the measurement by definition
. My understanding is that vacuums donít contain mirrors. My original device contained a mirror/splitter which interrupted the vacuum.
I wouldnít initially think that it would have an effect, but now that Iím asked, I have two thoughts on the topic: 1) Iíve read of double slit experiments that werenít supposed
to interfere with the light in a given slit, but somehow it seemed that the intent of measuring the flow through a slit was sufficient to affect the outcome of the experiment drastically. 2) Iíve opened a shutter (comprised of my hand and a copper pipe) and allowed a magnet to fall vertically through. Even though the magnet did not contact the shutter physically, the magnet's speed was regulated by the fields that existed at the time the magnet was passing through the shutter. It doesn't initially intuitively
seem like copper and a magnet would have this relationship, so I'm open to understand boundary conditions of other experiments.
Yes, I would have confidence in the speed being the same in those cases, at least between the front edge and back edge of the device. I would like to understand the boundary conditions of the shutter to see about extending that confidence to the region at and in front of the shutter.
I think Iím already satisfied with speed being independent of the source, since even sound and water waves offer that independence, so Iím really more interested in understanding the case where the observer is closing in on the light which seems like a different case. The binary star experiments that I know of were prior to the age of space exploration. Although they speak to the sameness of the speed of the twin lights, those older experiments would have been measuring light that spent the last leg of its journey through the earthís atmosphere which, at least in my imagination, could serve to regulate the twins to a new speed relative to the atmosphere (arghónow that I think about it, even the earthís magnetic field).
I wish I knew of a specific canonical experiment that gave me confidence about the boundary conditions. The one atmosphere-free measurement that I have recently read about involved the GPS satellites, but that experiment claimed to have resulted in a measurement of v+c, so Iím now disoriented.