Cecil Moore wrote:

This is similar to the problem that John Harrison faced
when he tried to design a clock for ocean travel. The
frame of reference was continuously changing so he had
to give up on his original design. It is way past time
for homo sapiens to give up on any notion of an absolute
frame of reference in a relativistic universe. The nail
that they drive in the floor under their feet is getting
longer with each passing day. Why can't they see that?

Such a thing as absolute references simply do not exist
in the universe of relativity. That gives a whole new
meaning to, "There are no absolutes!". Of course, I cannot
be absolutely certain ... what will happen on an absolute
foundation of jello ...

That is your opinion of Harrison's problem. I think the rest of us
would look at it quite differently. He made a clock to carry the
reference with the traveler. And the traveler could sync the clock by
telescopic observation using Jovian tables they had with them if they
were at a stable anchor. Almost an absolute reference I'd say. At
least for it's day.

Remember, we aren't talking about high velocity here, just position
changes, so the reference is not changing to any great degree.

tom
K0TAR