Happy Leap Day!

Happy Leap Day! Today, February 29th, comes only once every four years. Of course most of you probably know all of this already. Most of you, but probably somewhat fewer, know \*why\* we have leap years. The short answer is to keep the calendar in synch with the seasons. A longer explanation can be found here.

A deeper question is, why do we need the calendar to be in synch with the seasons? I'm not sure. Some origins are probably religious, so that we wouldn't have Easter in the winter and Christmas in the fall. Other reasons might be agricultural, so that people know when to plant and when to harvest and when the Nile is likely to flood. In today's modern age this is probably no longer necessary. The fixation on seasons probably originated in the northern hemisphere; the folks in Australia don't seem to complain that Christmas is in the summer. Well, maybe they do, but I haven't heard them.

What's notable about leap year is that it's based on actual astronomical principles: the relationship of the day to the year. This is unlike Daylight Saving Time, which is purely a social construction. DST doesn't actually save anything, and it causes a lot of confusion. Occasionally somebody is an hour off the next day, and occasionally I'm startled by the odd clock that I forgot to reset. Worse, different countries change times on different dates, so the usual time zone differences -- bad enough to begin with -- are temporarily made worse.

Leap years I can live with, but let's just get rid of DST.

Comments:

<i>Leap years I can live with, but let's just get rid of DST.</i>

Hear hear!

Posted by Mark J Musante on February 29, 2008 at 11:35 AM PST #

Actually, the truth is that DST, like leap day, is also a construct designed to make the natural progression of time fit the human methods of measuring it. Just as we measure seasons by the placements of equinoxes and solstices, we measure days by the sunrise and sunset, and by the zenith of the sun at midday. By convention we call midday noon, and set noon at 12:00 on our clocks. While we're content to let sunrise and sunset drift with the seasons, we want our high noon. But since the amount of daylight waxes and wanes with the seasons, noon drifts. In order to keep the sun's high point at noon, we have to move noon. Thus DST.

That being said, I'm all for abolishing it. Or rather, I'd like to stay on DST year round. I like the sun to rise later and set later. If it rose just a little later today, for example, instead of having failed to go to bed before sunrise, I could turn out my lights and sleep in the dark for at least a little while.

Hoot hoot.

Posted by Andi on February 29, 2008 at 10:27 PM PST #

I'm not sure I buy either premise.

Leap days are purely explained by a year not being an integral number of days. These are astronomical phenomena, not human measurement. Of course, the desire to fit an integral number of days into a year is a human one.

The difference between solar time and clock time is described by the Equation of Time:

http://en.wikipedia.org/wiki/Equation_of_time

So the sun is never more than about 16 minutes different from mean solar time. I don't think this explains DST.

I'm not entirely sure, but I think it has something more to do with people not getting up until the sun has risen but staying up long after dark. (I don't know whether this has a social or biological basis.) Shifting time an hour later thus makes the day seem longer.

I wouldn't opposed to switching to DST permanently. But it's pretty much the same as just getting up an hour earlier, so why bother? It's the shifting back and forth that I find irritating.

Posted by Stuart Marks on March 06, 2008 at 06:01 AM PST #

Post a Comment:
Comments are closed for this entry.
About

user12610707

Search

Archives
« April 2014
SunMonTueWedThuFriSat
  
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
   
       
Today