SERVICE INTERNATIONAL DE LA ROTATION TERRESTRE ET DES SYSTEMES DE REFERENCE
61 Av. de l'Observatoire
Tél. : 33 (0) 1 40 51 22 26
Universal Time, the conventional measure of Earth rotation is the traditional basis for civil timekeeping. Clocks worldwide are synchronized via Coordinated Universal Time (UTC), an atomic time scale recommended by the Radiocommunications Sector of the International Telecommunications Union (ITU-R)
and calculated by the Bureau International des Poids et Mesures (BIPM) on the basis of atomic clock data from around the world.
UTC is computed from TAI by the introduction of leap seconds such that UTC is maintained within 1 second of UT1. Since 1972, these leap seconds have been added on December 31 or June 30, at the rate of about one every 18 months. Since 1 January 2009, 0:00 UTC, UTC-TAI= -34s.
After years of discussions within the scientific community, a proposal to fundamentally redefine UTC will come to a conclusive vote in January 2012 at the ITU-R in Geneva. If this proposal is approved, it would be effective five years later. It would halt the intercalary adjustments known as leap seconds that maintain UTC as a form of Universal Time.
Then, UTC would not keep pace with Earth rotation and the value of DUT1 would become unconstrained.Therefore UTC would no longer be directly useful for various technical applications which rely on it being less than 1 second from UT1. Such applications would require a separate access to UT1, such as through the publication of DUT1 by other means.
The objective of the survey is to find out the strength of opinion for maintaining or changing the present system.
Your response is appreciated before 31 August 2011
1 - Nelson, R.A., McCarthy, D.D., Malys, S., Levine, J., Guinot, B., Fliegel, H.F., Beard, R.L., and Bartholomew, T.R., ?The leap second: its history and possible future.? Metrologia, Vol. 38, 2001, pp. 509-529
2 - Finkleman, D., Seago, J.H., and Seidelmann, P. K. The Debate over UTC and Leap Seconds. Proceedings of the AIAA/AAS Astrodynamics Specialist Conference,Toronto, Canada, 2010.