Saturday, March 7, 2009

What time is it?

Tonight we switch to daylight savings time here in the U.S. Well, most of the U.S. I once missed a meeting by an hour because I lived in Arizona which didn't use DST, but the meeting was on the Navajo Reservation which did go on DST. Or maybe the meeting was in New Mexico ... or the Hopi Reservation? I don't really remember, except that it was too complicated.

When we kept paper seismograms on a drum recorder before we went digital, we would mark the sheets with coordinated universal time (CUT) when we started and stopped the record, but we used the local date. That got to be too much when my assistants occasionally changed the paper later in the evening.

Anyway, my son was confused a few weeks ago because he thought he felt an earthquake in the Bay Area. He later found the SF Examiner reporting a regional quake at about that time. But the newspaper had mistakenly taken the reported earthquake time, in coordinated universal time, and mistaken it for local Pacific Coast time. So, the son was confused, but I straightened him out.

Most earthquake times are reported as CUT, which is essentially the same as Greenwich Mean Time, so that all seismologists will be talking about the same time when comparing data. Local media sources might report the quakes in local time. So watch out. Today, CUT is 5 hours ahead of Eastern Standard Time, but tomorrow CUT will be 4 hours ahead of Eastern Daylight Savings Time.

My source for things time is the U.S. Naval Observatory. We can read there that
Starting in 2007, daylight time begins in the United States on the second Sunday in March and ends on the first Sunday in November. On the second Sunday in March, clocks are set ahead one hour at 2:00 a.m. local standard time, which becomes 3:00 a.m. local daylight time. On the first Sunday in November, clocks are set back one hour at 2:00 a.m. local daylight time, which becomes 1:00 a.m. local standard time. These dates were established by Congress in the Energy Policy Act of 2005, Pub. L. no. 109-58, 119 Stat 594 (2005).
Yep, the dates were revised to save energy. How about driving smaller cars, everyone?

There's a nice WebExhibit on DST here.

And to get the CUT right now, click here.

So how about a little tune to make us smile while we "spring ahead" tonight and lose an hour of sleep. I heard this group during my freshman year when they were called Chicago Transit Authority. Ouch! Nice brass, guys.

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