Atomic clocks out of sync?

[LocalDude]

Dr Little states on page 81 of his book (The Theory of Elementary Waves) that "Clocks do not actually slow down when they move; they merely appear to slow down."

My understanding was that a moving atomic clock falls out of sync with a ground-based one and that if the moving clock is returned to earth and set next to the ground-based one, the two clocks will still be out of sync.

This sounds like a "real" effect and not just a visual one.

[prodos]

Lewis Little replied to this question by email. I reproduce his reply here:

In the book I have considered only the special theory of relativity. The special theory predicts no change to the actual rate of clocks.

The general theory [of relativity] does predict a change, and this is what is alleged to be observed in the experiments you mention. I say "alleged" because I have not as yet worked out the TEW picture of gravity/general relativity.

However, given the fact that gravity is a real physical effect, not merely the result of a change to one's frame of reference, a change to the rate of clocks would not necessarily be unexpected.

In my own follow-up question I asked Dr Little: What if there were two atomic clocks, stationary to each other and synchronized. Now one clock flies off, moves in a circle, and again meets up in the same spot with the other clock?

Dr Little explained to me (on the phone) that, as this scenario involves acceleration (rather than steady speed/velocity), it would also be part of a General Theory of Relativity explanation - rather than a Special Theory of Relativity explanation - and his comment (above) applies.