An important update from the International Earth Rotation Service

Which, I think I've mentioned, is the coolest name for any organization ever.

To: authorities responsible for the measurement and distribution of time

A positive leap second will be introduced at the end of June 2012. The sequence of dates of the UTC second markers will be:
    2012 June 30, 23h 59m 59s
    2012 June 30, 23h 59m 60s
    2012 July 1, 0h 0m 0s
The difference between UTC and the International Atomic Time TAI is:
    from 2009 January 1, 0h UTC, to 2012 July 1 0h UTC : UTC-TAI = - 34s
    from 2012 July 1, 0h UTC, until further notice : UTC-TAI = - 35s

This means that tomorrow, 4:59:59 PM PDT will be followed by 4:59:60 PM PDT prior to the advent of 5:00:00 PM PDT.

Of course there is a

Now that you know what a leap second is, have you wondered if you can see one? Can you hear a leap second? Several of us enjoy capturing leap seconds. You have to be quick; you have to plan ahead. You have only one second to fish and then wait a year or two, or even seven, before your next chance. Below are examples of catching a leap second in the act.

As a kid in the summer of 1972 I used a short-wave radio cassette audio tape recorder to record the first leap second. Alas, I still can't find that tape.

Also, great news, everybody! The venerable leap second has gotten a stay of execution until at least 2015: ITU Radiocommunication Assembly defers decision to eliminate the leap second. The Earth gently wobbles in relief.

Previously, previously, previously.

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19 Responses:

  1. tjic says:

    > Which, I think I've mentioned, is the coolest name for any organization ever.

    The Directorate of Time was awesome in exactly the same way, until the Navy renamed it.

    • johnboy says:

      The Directorate of Time was awesome in a slightly different way.
      Because it had a Director.
      Whose job title was Director of the Directorate of Time.

  2. n_by_nw says:

    The only possible rival for coolest name would be the Aircrash Bureau, which tells you when you're going down.

  3. Steve Allen says:

    The tone at the ITU Radiocommunication Assembly in January was something like "You raised this under-considered document to the international assembly without having achieved consensus?". The aftermath was Resolution COM6/20 (WRC-12) which has become WRC-15 agenda item 1.14, and its rather severe tone indicates that the plenary assembly expects the sub-groups to march double-time in order to present a better proposal by 2015.

  4. Infrogmation says:

    International travel could be quite disorienting back before the creation of the International Earth Rotation Service, back when every country set their own rate of rotation.

    • johnboy says:

      Are you kidding??!? In the eighteenth and nineteenth centuries each town set its own rotation.

      • In the nineteenth century, the town's railway station rotated independently of the town hall. So to speak.

      • Steen says:

        In the 13th century, Benedictine monks would occasionally record things like "yon towne hath a widdershins turning much unlike it's Fellowes, which is cause for muche distress amongst the Merchants"

  5. Let's hope the IERS doesn't give serious consideration to Tom Van Baak's proposals:

    "Earth as a frequency standard, suggested improvements:

    * Thoroughly clean, and dry with cloth
    ­* Remove surrounding gas and water vapor
    ­* Wait for core to cool before use
    ­* Re-align axis of rotation (wobbling)
    * Keep away from nearby moon (tides)
    * Keep away from sun (tempco)
    * Re-adjust rate (avoid leap seconds)"


  6. Phil says:

    iOS Dali Clock did not display 14:59:60. I'm disappointed!

  7. the q-man says:

    I captured it, as I'm sure many did. Thanks for reminding me. leap second 2012

    • Andy says:

      Yep, there's a patch proposed to fix the livelock.
      Oddly none of my SMP NTP machines crashed.

    • Yeah, that was pretty special. Also JVM and mysql processes going CPU-bound.

      Reading up on this stuff I found that Arthur David Olson designed, coded, and deployed a fix for this years ago, as part of his nearly-universal timezone database. Instead of fucking around with the system clock, you let the clock proceed at one second per second always and just correct the textual representations of times. Each leap second just means some new timezone definitions. Unfortunately the current POSIX explicitly prohibits this. I'm hoping that yesterday's Leapocalypse will get people to revisit this stupid standards issue and do it the right way.

  8. J. says:

    Thanks for the link. It looks pretty awesome:

    Project GREAT - General Relativity Einstein / Essen Anniversary Test:
    3 kids, 3 cesium clocks, a family road trip to measure relativistic time dilation

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