Dear Robert, I noticed that your question has been around for a month or so, and nobody attempted an answer. I am not sure if I understand exactly what you want to know, but the question reminded me of a section in the book "The End of Time" by Julian Barbour. In this book Barbour devotes a considerable amount of text to the issue of what clocks are or should be, and in the section "The forgotten aspects of time" (p. 132 ff) he claims that there is no good theory for clocks. To give a brief quote: "I know of no study that addresses the question of what a clock is (and how crucially it depends on the determination of an inertial frame of reference) at the level of insight achieved in non-relativistic physics by James Thomson, Tait, and Poincare. Throughout relativity, both in its original, classical form and in the attempts to create a quantum form of it, clocks play a vital role, yet nobody asks what they are. A distinguished relativist told me once that a clock is 'a device that the National Bureau of Standards confirms keeps time to a good accuracy'. I felt that, as a theorist, he should be telling them, not the other way around" (p.135). There are more interesting quotes in that section (and in the book), but it would take too much time to copy.

Maybe that book, together with Barbour's very interesting historical overview: "The Discovery of Dynamics" (basically about the clocks in the sky) can help you further in your quest.

Ahhh, someone understands and I thank you for your time and response. I would have thought that buy now the elements of time would have occupied many great minds in the sphere of physics as it has so in the sphere of philosophy. Perhaps my humble efforts at connecting such inaccessible phenomena such as dark energy , entropy and the like to the basic properties of time is yet uncharted? Again I am most grateful and will examine your references quoted..

You are too negative. Many great (and lesser) physicists have contemplated and written about at least some of the issues you mention and many other issues beyond that. The connection between entropy, dissipation, and time has been an almost constant topic in physics literature since around the 1850's. Dark matter I don't know, that has not been around long. Besides the Barbour books, I have books with titles like: Cycles of Time (Penrose), The Physics of Time Reversal (Sachs), The Physical Basis of the Direction of Time (Zeh), Time, a Traveler's Guide (a mixed bag of goodies by Pickover, and you'd probably like the chapter "Building an Einstein-Langevin clock"), A world without time (Yourgrau), Time, the familiar stranger (Fraser), Time's Arrow and Archimedes Point (Price), and quite a few more, written by physicists and philosophers, linguists, and musicians. The physicists are the more interesting (for me at least), but at the end of the books the questions we all have are not really answered, I'm afraid. Barbour is one of my favorites. Simultaneity was one of the important things Einstein thought about long and very hard. I think I could go on for some time about this, but it's already late. The question about what a clock is exactly, is, however, not asked very often, but entropy, and the structure of the universe, or possible universes (like the Godel universe in Yourgrau's book) looms large in almost all of them. So, good luck in trying to find the answers, but don't be too dismissive of all the attempts that scientists already made.

Dear Gert,

Without trying to be boring I found a copy of a lecture that Albert gave before the Prussian Academy of Sciences January 27, 1921 which I will give a brief quote that applies probably as much now as then:

"Sub specie aeterni Poincare, in my opinion is right. The idea of a measuring-rod and the idea of the clock coordinated with it in the theory of relativity do not find their exact correspondence in the real world. It is also clear that the solid body and the clock do not in the conceptual edifice of physics play the part of irreducible elements, but that of composite structures, which must not play any independent part in theoretical physics. But it is my conviction that in the present stage of development of theoretical physics these concepts must still be employed as independent concepts; for we are still far from possessing such certain knowledge of the theoretical principles of atomic structure as to be able to construct solid bodies and clocks from elementary concepts.".

Indeed a question that has been around. Now I have some reading to catch up on. Thank you again sir!

You're welcome. Thanks for the quote. Barbour refers to a lecture Einstein gave in 1923 about this topic, but does not give the reference, he only states that Einstein "was well aware that this [the way he presented relativity] was ultimately unsatisfactory". Pais ("Subtle is the Lord...") lists no lectures in 1921 or 1923 in Prussia. Could you post the copy you have, or send it to me?

On it's way but later. I sent a message to explain.