Interesting news for physicists and tiny watchmakers reported by Eurekalert on the feasability of the "ideal clock" [eurekalert.org]. From the article:
"A team of physicists from the universities of Warsaw and Nottingham have just shown that when we are dealing with very large accelerations, no clock will actually be able to show the real passage of time, known as "proper time"
"In both theories of relativity, special and general, it is tacitly assumed that it is always possible to construct an ideal clock - one that will accurately measure the time elapsed in the system, regardless of whether the system is at rest, moving at a uniform speed, or accelerating. It turns out, however, that when we talk about really fast accelerations, this postulate simply cannot apply," says Dr. Andrzej Dragan from the Faculty of Physics, University of Warsaw."
The full paper [arxiv.org].