Friday, January 2, 2009

Time and Time Again




I'll be 39 this year. Sometime in August, I think. If we hang together often, you'll notice that I have a problem with time...dates...remembering things chronologically. If something happened last week, I couldn't say if it was a week or a month ago. I can never remember how old I am. When asked, if I don't figure out the current year and subtract 1971, I always say 19. It's not Freudian; I honestly don't remember what was happening in my life at 19. Not that I don't remember it, I just don't remember if I was 19 when it was happening. Is this making any sense?

Anyway, a few days ago (I'm assuming) a co-worker was remarking on the rules for Leap Year - they're weirder than you'd think, and I'd link if I knew what site she was reading - and it reminded me of the only justification I've found for my problem. Have you ever heard of Universal Time? I hadn't.

I stumbled across this site (I don't remember when or how) and after reading, I was stunned.

UTC (Coordinated Universal Time) is "determined using highly precise atomic clocks", "defined in terms of an atomic transition of the element cesium under specific conditions, and is not directly related to any astronomical phenomena" and as such is "...the basis for the worldwide system of civil time".

UT1, on the other hand, is "...a measure of the rotation angle of the Earth as observed astronomically. It is affected by small variations in the rotation of the Earth..."

So UTC is precise, exact, reliable, while UT1 is based on a wobbling, spinning, changing phenomena. Hrmph. That might help us determine how long something takes, but it's never gonna change what time it is.

"One can think of UT1 as being a time determined by the rotation of the Earth, over which we have no control, whereas UTC is a human invention. It is relatively easy to manufacture highly precise clocks that keep UTC, while the only "clock" keeping UT1 precisely is the Earth itself. Nevertheless, it is desirable that our civil time scale not be very different from the Earth's time, so, by international agreement, UTC is not permitted to differ from UT1 by more than 0.9 second. When it appears that the difference between the two kinds of time may approach this limit, a one-second change called a "leap second" is introduced into UTC. This occurs on average about once every year to a year and a half."

Leap Seconds??

(link updated 11/17/2010)

(Original photo by Ross Berteig, some rights reserved.)

2 comments:

  1. You lack of time concept is why you have a Marci in your life. I love you with all my heart and soul!!!

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  2. To Marci:

    Thank you for being there for me always, ever the same. I'm here for you, even though I'm not half as competent. You are all the best friend I could've ever asked for if I'd known the best stuff to ask for. I love you too, you know. Unconditionally, always.

    -Patti

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