Today we gain a leap second. Why?

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It may only be an extra second, but I’ll take whatever I can get.


This is rather oddly worded. “…adding a leap second allows astronomical time to catch up to atomic time.” It’s the opposite - the atomic time is held back, waiting for the reality of a slow Earth.

I was on the Time Nuts mailing list ten years ago, and hoo boy, you should see how mad some of those folks get when discussing leap seconds. The big problem is that they are not predictable, so time code that works far into the future is impossible to write. Your clock has to receive a message telling when the leap second is about to take place.


The main reason is today is my birthday. I deserve an extra second to celebrate.


PBS Space Time just did an episode on this that was fun and raised the question, if we eventually leave Earth will it still make sense to adjust the calendar to stay in sync with season on a planet we no longer inhabit.

You should hold out for a whole extra cake.


…? Those sound like the exact same thing.

If I am a fast runner and you are slow, and you make me stop for one step, you could say

  • making me stop allows you to catch up to me
  • making me stop holds me back, waiting for you

“You catch up to me” is the same as “I wait for you.”

“astronomical time to catch up to atomic time.” is the same as “the atomic time waits for the reality of [astronomical time].”

These guys must be pissed right … about … NOW.

When I was a young, young engineer I used to write time libraries for fun… In production code. Yes, that is the engineer equivalent of going down to the London docks in 1650.

First production code blowup was a… Keep calm, just let it out… Was a divide by zero bug in this lib right after new years eve.

Without exception handling.

I have learned to respect, loathe, fear, and sometimes feel affection for time.

But seriously I have a mysql cluster ntp’d to Greenwich and when in query “select now()”. You want your time in Sri Lankan time zones? Navajoe time zones? McMurdo station? On a plane flying west?

Heh, screw you, you get gmt and you’ll like it.

(EBay uses PST and pdt on all their servers. I can’t make this up. except for the ones that don’t!!


Some years ago a local TV reporter phoned me to ask what the relationship was between leap years and the resurrection of Christ. It took a while before I was convinced she was not someone pranking me.

Why? Because leap first doesn’t make any sense. Unless you like to live dangerously, of course.

Will this be deducted from the end of my life?

Happy leap second!

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I was hoping for a better answer than “because otherwise the time would be wrong”. You know, an answer that would let me predict when the next time they will do this is. But I suppose the only real answer is “because we said so”.

My employer uses GMT on the server that hosts published content, so that all the listed “published on” dates are one day earlier than the date here in the states when we publish anything.

This was not true before mid-2013.

We link to our own older pieces with link text that includes publication date.

There, all links in older pieces now look wrong.

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