Wednesday, November 17, 2010

Yeah, So, I'm Getting Less Certain That I Really Understand How the Sun Works

To continue the conversation about sunrise/sunset times and the calendar. . . .

Why doesn't the winter solstice feature the latest sunrise and earliest sunset of the year? The gist of it is that solar noon -- that is, the time at which the sun reaches its greatest height in the sky -- doesn't match up with what we call noon according to our clock time. The time between solar noons is not exactly 24 hours, so solar noon occurs at a slightly different clock time every day. (Today, in New Haven, solar noon was at about 11:36 AM. It varies by latitude.) Approaching the winter solstice, solar noon is creeping later by a good 30 seconds every day. So even though there's less daylight, it occurs later in the day; and the net effect pushes the sunset time later. Of course you're absolutely getting your ass handed to you in terms of sunrise time while this is happening.

You can read about this at the EarthSky website, here and here. (Note that these articles are pre-posted for some reason and dated in December 2010, so their sense of "now" isn't accurate yet.)

In a vague sense I understand this to be about the usual season-inducing combination of Earth's tilt and its path as it rotates around the sun, but I still haven't gotten my mind wrapped around the specifics yet. You can take a gander at your local solar noon calendar here. Connecticut's earliest solar noon was two weeks ago (11:35, although that's 12:35 counting daylight savings time), and I can't figure out why a pivot point in the calendar cycle would happen in early November. Mysteries for another day.

I feel like there must be some family ancestors, like farmer types, who would have been absolutely appalled that a descendant of theirs would have been this unaware of daylight cycles for so long. I blame it on clock time and that devil's electricity.

* * * * *
Also via EarthSky, there's a Blue Moon this Sunday, at least by one definition. Remember, stay safe! If I'm remembering my Maine Farmer's Almanac correctly, on Blue Moon nights it is the plight of certain accursed souls to wander the woods from sundown to sunup, hideously transformed into the form of a 1950s doo-wop bass man. Do not get bitten by one of them, not unless you want to be a bass man too.


Post a Comment

<< Home