Introduction to Some Fundamental Concepts of General Relativity and to Their Required Use in Some Modern Timekeeping Systems

C.O. Alley

Abstract:	This is a largely tutorial lecture on the basic ideas of General Relativity - Einstein's theory of gravity as curved space-time - emphasizing the physical concepts and using only elementary mathematics. For the slow motions and weak gravitational fields which we experience on the earth, the main curvature is that of time, not space. Recent experiments demonstrating this property (Alley, Cutler, Reisse, Williams, et all 1975 and Vessot and Levine, 1976) will be briefly reviewed. The extraordinary stability of modern atomic clocks makes it necessary to understand and to include the fundamental effects of motion and gravitational potential on clocks in many practical. situations. These include the NAVSTAR/Global Positioning System and time synchronization using ultra stable clocks transported by aircraft. In future system such as global time synchronization using clocks in law earth orbit, the accuracy may be limited by uncertainties in the calculated proper time of the travelling clock, rather than by intrinsic clock performance.
Published in:	Proceedings of the 13th Annual Precise Time and Time Interval Systems and Applications Meeting December 1 - 3, 1981 Naval Research Laboratory Washington, DC
Pages:	687 - 727
Cite this article:	Alley, C.O., "Introduction to Some Fundamental Concepts of General Relativity and to Their Required Use in Some Modern Timekeeping Systems," Proceedings of the 13th Annual Precise Time and Time Interval Systems and Applications Meeting, Washington, DC, December 1981, pp. 687-727.
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