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Decoupling Civil Timekeeping from Earth Rotation

A Colloquium Exploring Implications of Redefining UTC in Astrodynamics, Astronomy, Geodesy, Navigation, Remote Sensing and Related Fields

5-6 October 2011 (Wednesday - Thursday)
Headquarters Building, Analytical Graphics, Inc.
220 Valley Creek Blvd, Exton PA, 19341-2380
(near Philadelphia)


Rob Seaman, National Optical Astronomy Observatory
John H. Seago, Analytical Graphics, Inc.
Steve Allen, University of California Observatories / Lick Observatory

For additional information, email: info(AT)futureofutc.org


Universal Time - the conventional measure of Earth rotation and astronomical time-of-day – is the traditional basis for civil timekeeping worldwide. Since 1972, Coordinated Universal Time (UTC) has remained a broadcast convention for labeling uniform atomic seconds so that civil clocks remain synchronized with Universal Time of day to better than one second. Because UTC began with radio broadcasts, its prescription has been maintained by the Radiocommunication Sector of the International Telecommunication Union (ITU-R).

A conclusive proposal to fundamentally redefine UTC is scheduled for a vote by the Radiocommunication Assembly of the ITU-R in January, 2012. The proposal will halt the contribution of so-called leap seconds to UTC after 2017, and will also terminate the requirement that time services transmit the difference between UT1 and UTC. If approved, UTC would no longer be useful as a type of Universal Time for most technical applications.

Many software and hardware systems needing to know how the Earth is oriented with respect to the sky rely on UTC for this purpose. Should UTC be redefined, significant consequences may be anticipated for applications and infrastructures across various fields. Applications that do not apply so-called Earth Orientation Parameters and/or DUT1 corrections to UTC would be most affected.

Purpose and Scope

Adverse impacts from redefining UTC have not been extensively researched and documented. This colloquium thus intends to gather experts and operators from fields that may be commonly affected to document and discuss potential problems. An additional aim is to focus on pragmatic timekeeping solutions relevant to the various possible future outcomes of UTC-related changes. Affected technologies may be related to astronomy, astrodynamics and celestial mechanics, geodesy, ground-to-space satellite communications, navigation, remote sensing and space surveillance. Decoupling the readings of clocks from the rotation of the Earth may also have legal consequences and sociological ramifications that have not been fully explored. The mitigation of undesirable effects could require substantial resources and would benefit from careful planning among affected parties.


Presentations and supporting manuscripts are solicited on topics related to any potentially unfavorable impacts that might result from changing UTC, and proposed mitigation strategies to be employed (if known). Proposed manuscripts will be considered and accepted based on a submitted abstract that describes a topic within the scope of the meeting, subject to the space and time constraints of the venue. Submissions that emphasize specific technical issues, operational impacts, and financial aspects (cost of exploration and testing, software, hardware, and documentation changes, lost product marketability, etc.), as well as survey works investigating such, are especially encouraged. This is a working meeting soliciting international participation with English as the working language.

By Friday, 19 August 2011, prospective contributors are expected to provide:

1. A proposed subject title as well as the name, affiliation, postal address, telephone number, and email address of the presenting author,

2. An extended abstract of at least 300 words that includes a clear and concise statement of the subject area to be addressed and an explanation of its significance to potentially adverse impacts that might result from changing UTC,

3. A summary (~100 words) to be included in the conference program.

Potential contributors are encouraged to submit abstracts as early as possible using the online submission form.

Detailed author instructions will be provided following acceptance.


Each participant will be requested to provide both a scheduled talk and a written manuscript to the colloquium proceedings that conforms to the meeting’s proceedings format. By submitting an abstract, the author affirms that the proposed submission shall be reproducible as part of the proceedings. An edited transcript of roundtable discussions in response to questions within the meeting’s scope may also be included as part of the proceedings. The conference proceedings format template is available from Univelt Publishing.

Program and Logistics

Program details will be posted to this web site and emailed to participants as such information become available.

latest revision, 31 May 2011, RLS