My first blog was about time zones.  As far as I can tell, no one actually read it.  I know this because several people told me they didn’t read it because it sounded boring.  Others told me by repeatedly asking what the time difference would be for me in South America.

Time Zones parte uno

Joss Whedon once said, I paraphrase, that he would rather write something a thousand people NEEDED to read rather than something one million people WANTED to read.  In that spirit, I give you a Time Zone sequel.

Last night, at 2am, those of you in the United States had a temporal adjustment thrust upon you and you awoke to find yourself in the hellish landscape that is Daylight Savings Time.  Clocks were bumped immediately to 3am and you felt just a little bit off, sunlight not quite in the right place as you went about your morning.  As an amateur astronomer, I generally hate DST.  It means it doesn’t get dark until quite late so I have to stay up inordinately long to do any observing in the summer.  And it isn’t as if the rest of you don’t use artificial lights to light up any outdoor activity you pursue anyway.  But, whatever, DST has begun.

Time, obviously, has not changed.  At 2am last night your orientation to the Sun did not change at all except in the way that it constantly changes with the rotation of Earth and the revolution of Earth about the Sun.  Yours and my relative orientation in space has not changed.  Nothing at all actually changed except where you set your clocks.  DST is a completely artificial construct set about by politicians you hate and whose judgement you do not trust.  And, so, it is sacred.

Of course, time as we use it is also and always artificial.  Noon has a real meaning: middle of the day, the time at which the Sun crosses the meridian and moves from the eastern part of the sky to the west; the point at which the Sun is highest in the sky, however high that is.  In the days before inter-village travel was common, time was measured by a sundial or equivalent in each town.  Every town had a different time because the Sun crosses the meridian at different times for any two different longitudes.  When travel between towns became faster, most notably with train travel, it became useful to have regions operating on the same time.  Thus, the time zone was born out of railway time that had been devised so people could predict what time their train would depart another town without doing spherical geometry.  Now, virtually no one sees the Sun at its highest point at noon proper.  The deviation can often be substantial.  DST adds to that.  In Winston-Salem, the Sun will cross the meridian today at 1:30pm, which means, yesterday, before DST kicked in, it crossed the meridian at 12:30pm, half and hour later it should have based on astronomical definitions.

We here in Chile continue to operate under DST, it being late summer now.  We won’t “fall back” until May 15, which would actually be a more reasonable time for DST in the north.  Alas.  In any case, with the northern hemisphere, or at least the parts that concern us in Southern Cone the most, “springing ahead” last night, the gap between Santiago and Winston-Salem closed to one hour.  On May 15, when we fall back, we’ll pull even with EDT and you’ll get to read parte tres.


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