************************************************************************ IERS Message No. 191 June 28, 2011 ************************************************************************ Colloquium on redefinition of UTC - Announcement Decoupling Civil Timekeeping from Earth Rotation A Colloquium Exploring Implications of Redefining UTC in Astrodynamics, Astronomy, Geodesy, Navigation, Remote Sensing and Related Fields October 5-6, 2011 Headquarters of Analytical Graphics, Inc. 220 Valley Creek Blvd, Exton PA, 19341-2380 (near Philadelphia) Registration is now open at http://futureofutc.org Universal Time - the conventional measure of Earth rotation and astronomical time-of-day - 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). A proposal to fundamentally redefine UTC will come to a conclusive vote in January 2012 at the Radiocommunications Assembly of the ITU-R in Geneva. It would halt the intercalary adjustments known as leap seconds that maintain UTC as a form of Universal Time, and eliminate the requirement that time services transmit the varying residuals (DUT1) between Coordinated Universal Time and Universal Time of day. If the proposal is approved, UTC would not keep pace with Earth rotation and the value of DUT1 would become unconstrained. Adverse impacts from redefining UTC have not been extensively researched and documented. The implications extend from technical infrastructure to legal, historical, logistical, sociological and economic domains. Affected technologies may include (but are not limited to) applications in astronomy, astrodynamics and celestial mechanics, geodesy, ground-to-space satellite communications, navigation, remote sensing and space surveillance. This meeting will provide a venue for discussing and documenting the repercussions of changing UTC along with possible mitigation strategies. Co-chairs: Rob Seaman, National Optical Astronomy Observatory John Seago, Analytical Graphics, Inc. Steve Allen, University of California Observatories / Lick Observatory ************************************************************************ IERS Messages are edited and distributed by the IERS Central Bureau. To submit texts for distribution and to subscribe or unsubscribe, please write to <central_bureau@iers.org>. Archives: http://www.iers.org/Messages/ ************************************************************************