Friday, January 20, 2012

Earth's Temporal War Leaps to 2015, one Leap Second at a time

Back in August of 2011 I covered The current Temporal War on planet Earth. Which documented the factions that wanted to keep Leap Seconds as used today, and those that wanted to abolish Leap Seconds.

In our current methodology of keeping time, an extra second is inserted or removed in the Clock-On-The-Wall-Time to keep it in sync with the Look-Out-The-Window-At-The-Sun-Dial-Time (the distinction between Synodic, Solar, Sidereal, Stardates, UTC, UT1 and the myriad of other time scales would make for a much longer blog entry). Those against Leap Seconds say they are to hard to deal with over long spans of time where accuracy and precision are required. The people on the other side of the temporal war want to look out the window and have the clock-on-the-wall agree with what they see out the window. You see that if Leap Seconds are removed the two time scales drift apart. Someday High-Noon Wall-Clock-Time, would be the middle of the night Sun-Dial-Time.

This week the body that governs the time scales was set to vote on keeping or eliminating Leap Seconds. Seems there is no agreement on how to 'fix' the Leap Second 'problem' so the vote has been moved to 2015:

ITU Radiocommunication Assembly defers decision to eliminate the leap second

Geneva, 19 January 2012 – The ITU Radiocommunication Assembly has reached an important decision to defer the development of a continuous time standard in order to address the concerns of countries that use the current system of the leap second in Coordinated Universal Time (UTC).

The decision has been reached to ensure that all the technical options have been fully addressed in further studies related to the issue. These studies will involve further discussions within the ITU membership and with other organizations that have an interest in this matter and will be referred to the next Radiocommunication Assembly and World Radiocommunication Conference scheduled for 2015.

Adjustments made in one second steps, known as ‘leap seconds’, have been implemented since 1972 to compensate for variations in the speed of the earth’s rotation within the framework of Coordinated Universal Time (UTC).

UTC is defined by ITU’s Radiocommunication Sector and is maintained by the International Bureau of Weights and Measures (BIPM) in cooperation with the International Earth Rotation and Reference Systems Service (IERS). Measurements from timing centres around the world are used in the determination of UTC, which is adjusted to within 0.9 seconds of Earth rotation time (UT1) by IERS-determined values of the Earth’s rotation.

The suppression of the leap second would make continuous time scale available for all the modern electronic navigation and computerized systems to operate with and eliminate the need for specialized ad hoc time systems. This however may have social and legal consequences when the accumulated difference between UT1 – Earth rotation time – would reach a perceivable level (2 to 3 minutes in 2100 and about 30 minutes in 2700).

ITU Secretary-General Hamadoun Touré considered the decision taken by the Radiocommunication Assembly will ensure that all stakeholders have been adequately associated with a step which will clearly influence our future.

So we tick on with the Status Quo in our Embedded Systems...

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