This month the church’s writers group had three words to choose from: Dance, memory and the calendar. Here’s what I wrote for them:

I’m sitting here looking at the three words, “dance,” “memory” and “the calendar.”  Dance is off the list.  Nobody should be subjected to watching me dance.  The next word, memory, has possibilities and I thought about what I could write about it, but I can’t remember what I wanted to say.

Which leaves me with “The Calendar.”  First there is no one, “The Calendar.”  There’s a ton of them: Roman, Julian, Gregorian, Jewish, Lunar, Islamic, Hindi, Catholic, Eastern Orthodox, Mayan … I mean are we talking an arithmetical or astronomical calendar?  Are we talking about just keeping track of days or are we including concepts like months, years, and centuries.  What about the time of day? Is that including in this mythical, “The Calendar?”

I suppose we could just narrow things down a bit and say we’re talking about the Gregorian calendar that most of us use.  I could spend a lot of time diving into the history of the Gregorian calendar and how it is really just a Julian calendar with some better corrections for the fact that it’s an arithmetical calendar trying to be an astronomical calendar that maps to the solar year.  Of course it doesn’t — never has and won’t.  Currently the solar year is 365.2422 days long while the Gregorian year is 365.2425 days long on average.  We only get to that number because we sometimes have a leap year.  The obvious problem is that the numbers don’t match and over the next million years or so the solar year will likely get longer as the earth starts spinning slower and we’ll need a new calendar.

Not that it really matters because most of us won’t be here then and honestly these days the only use I have for a calendar is to know if I have a doctor’s appointment.  It’s also useful to know if it’s July or December so I can decide if the heater or the A/C should be on.

Of course all of this makes me think about leap seconds and the havoc that caused in my computer lab in 1998, and again in 2005.  I’ll grant you it’s more about time in terms of minutes and seconds like you see on a watch rather than whether it’s Tuesday or Friday, but it’s a similar concept to a leap year — correcting between the time on a watch and observed solar time.  Did you know that there are three kinds of time keeping methods? There’s Coordinated Universal Time (UTC) which is used as the reference for the civil time displayed on your cell phone.  In the past this was also called Greenwich Mean Time (GMT).  Then there is International Atomic Time (TAI) — the acronym based on the French spelling, but that’s not important.  Lastly we have  UT1 which is the observed solar time which you get by observing when the sun crosses its highest point in the sky at around noon.

As you can imagine these three times never quite match up.  Earth’s rotation is erratic and varies due to a lot of factors you don’t want to hear about. Which brings us to the problem that the Atomic clock never varies (it’s Atomic) while the observed time bounces all over the place caused UTC time to often be wrong by plus or minus a second.

So a leap second is added every so often to correct the whole thing.  This process causes an untold amount of grief to us computer engineers for little no real value.  Computers have enough trouble with leap years and daylight savings time.  Try to add an extra second to a minute in a random day just causes a computer to have the computer equivalent of a nervous  break down.  Not all computers, some are better at not caring what time it actually is than others.  About half the ones in my lab did okay while the others had a problem with NTP configuration but I’am reasonably sure you don’t want to hear the details of that.

Well, after thinking about all three words, I think I’ll just skip writing this month and do something for next time.