Hoover Dam image from this siteI had a snippet of a conversation with one of my uncles this Christmas (he's a long time computer technician so snippets of conversation are about all you ever get out of him).
He mentioned working on the leap second and speculation that among other things, dams were responsible for the increased rapidity in the frequency of leap seconds.
(if you haven't figured it out already, dams keep water from flowing back to sea level, thereby placing more mass farther from the earth's center thus slowing the planet's rotation by a tiny amount more than would be accounted for by natural circumstances. For analogy think of the arms of a skater, bringing them in can speed a rotation while extending their arms slows their rotation)
5 comments:
Galciation (and melting of said glaciers) would have more effect on the conservation of angular momentum, I would think. The melting of the Greenland icesheets bythemsleves would probably more than offset the effects of all dams. This almost makes me want to go play around with equations again. Almost....
I was mostly looking for an excuse to post that picture (Damn, that's a dam).
And I did use the weasel words of 'among other things' when citing the influence of increased damming on the unexpected increase in the rate of slowing.
Also another factor to consider is better ability to calculate with precision given the tiny fractions of fractions you must deal with to compute the need for these leap seconds.
An aside, I was probably in about the last class of intermediate algebra students who learned to use slide rules (it was far from necessary in '85, but we had an instructor doggedly old school), I bet you almost reached for one though, Icepick.
Slide rules were before my time, XWL. Let's see, intermediate algebra would have been about ... oh, I guess it would be 1981 or 1982. We had passed by slide rules, but hadn't yet progressed to the point where scientific calculators were mandatory. (Graphic calculators were damn near unimaginable in that dark age.) The teachers knew slide rules were dead, but were reluctant to force everyone to buy a calculator. So we did it all on paper. Ah, those were the days....
What is this "slide-rule" you speak of? Is that the one where the runner has to stay in the base path while sliding?
Pooh, a slide rule was a torture device the ancients used on children and engineers. A flat wooden board with mystical markings and a sliding piece in the middle. Kind of the (Space) Alien Anal Probe (tm) of its day.
Post a Comment