Hi:
I am sorry but I think you are going to become impatient with me and my purpose. Measuring is something I can do but I never use a rubber tape.
I never say "a clock measures time". If pushed to it I would likely say a clock measures elapsed time or possibly, while waiting for my date, I might say a clock measures my time to wait. To me the use of a clock is like a calendar. It tells me what is gone and what should be comming.
You ask; "what does it mean when we say one clock is more accurate than another?" Really!
How do you decide which one is faulty? If we are getting to a point where velocity causes clocks to differ, that is between the one on Earth and the one racing to Neptune, I could likely accept that as reasonable but I still fail to see where people use that to argue space travelers at close to SOL age less. You are very convinced of your GR. I appreciate your efforts.
jjw
