Leap second to be added to the official world time

On December 31, at 23:59:59 UTC, a leap second will be added to the official timekeeping clocks of the world. That's because the timescales of atomic clocks and the earth's rotation aren't perfectly in synch. The last leap second was added in 2005. From Smithsonian:
Earth’s rotation is the traditional form of timekeeping. It is what defines a day. However, while we call a day 86,400 seconds, it is really 86,400.02 seconds. All those .02 seconds add up over time. In addition, the earth’s rotation is not constant (it has been slightly slowing, and 900 million years ago a day was only 18 of our hours). Time as we know it changes.
"Leap Second Added to Your Calendar"


  1. Math geeks get your calculators out! How long will it be before the earth stops having days? Will we fall off?

  2. This brings back nightmares about clock systems. One place we had a perfectly modern master clock but the slaves were the stepper type that went clunk, clunk, clunk. Whenever we went from standard to Daylight Savings and back I had to count on spending half a day on a stepladder.
    I later had to deal with a similar system but this one still had a physical pendulum clock as the master.
    Schools seem to favor the clock that is always wrong. It runs the wrong speed and then syncs at the minute or half minute.
    The so-called atomic clocks we’re being sold use the low frequency transmission from Ft. Collins Colorado (WWVB) which is at 60 Khz.

  3. Given that the second between 23:59:59 31-DEC-08 and 00:00:00 01-JAN-09 is arguably the most intensely observed second on the entire calendar, with hundreds of millions of people in the GMT zone alone counting down to the New Year, couldn’t they have picked a better time to do it?

    Are we supposed to say, “Three… two… one… extraleapsecond… HAPPY NEW YEAR”? That seems like a pain in the ass, and yet if we’re going to be accurate, what are we to do?

  4. DAMMIT! Now I’m going to have to change all my clocks AGAIN! Why can’t we just pick one time and stick with it?!!??

  5. add a second? Just like that? Make it up?? What a mockery, it might as well be that the whole time thing is just something people made up in the first place.

  6. The math geek in me needs to point out something:

    If each day has an extra .02 seconds in it, we’d need to be adding a leap second every fifty days. So either each day is more like 86,400.001 seconds (which would allow for a three-year gap) or something’s off.

    In fact, this page: http://tycho.usno.navy.mil/leapsec.html points out that it’s actually 86,400.002 seconds per day, and that we add a leap-second ‘a little less than once per year.’

    Also, the length of a day varies – presumably because of tidal forces from the moon, varying distances from the sun, etc., so there are additional corrections.

    I feel so much better.

  7. Actually the “leap second” can be positive or negative, and it’s meant more to keep us in line with “solar noon” or noon when the sun is at apogee. The second is added the last day of June or December as needed. However there has been a movement recently to abolish the leap second, possibly in favor of the leap hour. I myself endorse the “leap nap time”, to be added liberally as needed throughout any day.

  8. It’s astounding, time is fleeting
    Madness takes its toll
    But listen closely, not for very much longer
    I’ve got to keep control

    I remember doing the TIme Warp
    Drinking those moments when
    The blackness would hit me and the void would be calling
    Let’s do the time warp again…
    Let’s do the time warp again!

    It’s just a jump to the left
    And then a step to the right
    With your hands on your hips
    You bring your knees in tight
    But it’s the pelvic thrust that really drives you insane,
    Let’s do the Time Warp again!

    It’s so dreamy, oh fantasy free me
    So you can’t see me, no not at all
    In another dimension, with voyeuristic intention
    Well-secluded, I see all
    With a bit of a mind flip
    You’re there in the time slip
    And nothing can ever be the same
    You’re spaced out on sensation, like you’re under sedation
    Let’s do the Time Warp again!

    Well I was walking down the street just a-having a think
    When a snake of a guy gave me an evil wink
    He shook me up, he took me by surprise
    He had a pickup truck and the devil’s eyes.
    He stared at me and I felt a change
    Time meant nothing, never would again
    Let’s do the Time Warp again!

  9. You know the 18 hour comment made me wonder:

    From what little I see on the internets….Has anyone looked into the way plants have adapted to having more sunlight per day? And or conversely, did we still have roughly 365 days a year, or was that factored into a higher orbital speed or what?

    Guess what I’m getting at is, a LONG LONG time ago Earth is not as we know it.

  10. As a man with a 12/31 birthday, I thank the International Brotherhood of Crazy Accurate Timekeepers for giving me one more second of special-ness this year. I will try to use that second to have my way, and over a lifetime I hope to accrue at least an extra minute over all you suckas!

    @#17 BCSIZEMO: Bear in mind that 900 million years ago, earth had developed unicellular life, but multicellular life was still 250 million years away. So neither we nor plants were spinning around crazily saying “day! night! day! night! OMG time flies!”

    It’s also a really interesting dynamic about evolution (of life, but also of technology, ideas, and other complex systems) that it tends to accelerate, because it is a cumulative process, like population. In other words, earth life has become much more dynamic diverse complex and in some cases advanced in the last million years than it has in the previous 10 million years combined. (Ouch I am painfully oversimplifying. Not even taking into account the “reboots” earth life went through with mass extinctions, etc.) Likewise there are more books published this year alone (6 million) than in the entirety of any single decade of the 1800s (I don’t have numbers but you can imagine).

    Additionally, I do not know, but do strongly suspect, that the decelaration of earth’s rotation has itself been decelerating – that we are slowing down less today than we were 900 million years ago. If that happens to be the case, then most of multicellular earth life as you know it – the plants and animals – may have developed with something much closer to the 24 hour day and 365 day year than you first concluded from the article.

  11. Shouldn’t “while we call a day 86,400 seconds, it is really 86,400.02 seconds” be “while we call a second 1/86400 of a day, it is really 1/86400.02 of a day”? I know it technically says the same thing, but the whole point here is that the day (Earth’s rotation) is the real and absolute thing we are keeping up with, while the second (as defined by our atomic contraptions) is the thing we invented to keep track of it. That makes sense to me. Just from the use of “really” in that quote, the article seems assume that a “real” second is “so many oscillations of a cesium atom” (or whatever it is), rather than the old “1/86400 of one rotation of the earth relative to the sun”.

    #13; Yeah, I noticed that too. But I didn’t go any farther than “.02 is 1/50 and not 1/(365×3), so either .02 wrong or I’m missing something”.

Comments are closed.