There are a lot of things in this arena that have not been set in stone... and while the meter has been tied to the speed of light, you can't use that as an excuse to say that the speed of light has no variability. What happens is that any change in the accepted speed of light will cause a change in the definition of a meter - which is intolerable because science depends on rock-solid, while still laboratory-reproducible, standards.
I am particularly concerned with the error caused by effects of certain types of fields, such as gravity. > > Where did you obtain the misinformation that the speed of light in a > vacuum is a variable constant? It (c) is now *defined* as an exact > numerical constant which has *no* variability! It is the realization of > the meter, *from* c and the atomic second (the s in SI), that always has > some experimental error. > > Gene.
