The sun also sets

About this time every year, as the sun sets well before 4:30 PM (I live near Boston), I start to pine for the days to get longer again. Which is too bad, because they won’t actually get longer, as every school child knows, until after December 21st, or thereabouts. But I have an ace in my back pocket that most people don’t know about. The sun will start setting later as of about December 9th or so. How can this be, you ask, if the days are still getting shorter? The balance is maintained by the fact that the sunrise will continue happening later and later until January 3rd, leaving the solstice snug on December 21st. But since I never wake up early enough to see the sunrise, then I am free to celebrate my own little pagan happy dance on December 9th.

While poking around the Christmas sale goodies at the Sky & Telescope site, I came across a dandy online sky chart that let me verify the rough time of sunset for my hometown. I got curious to see what the exact time of the earliest sunset would be, and soon turned up at the US Naval Observatory’s site where I could generate the sunset table for a year. Sure enough, 4:12 PM on December 9th ought to just about do it.

If you’re interested in why the earliest sunset is not on the shortest day of the year, the short unsatisfying explanation is that the Earth’s orbit around the sun is a slight oval and not a perfect circle. The long unsatisfying answer is here: Sunrise And Sunset, Position of the Sun. Beware, the answer includes the phrases “obliquity of the ecliptic” and “non-zero eccentricity.” The long satisfying answer involves lots and lots of drawings of the three dimensional geometry of planets which I am too tired to provide.

It’s easy to paint a picture of our ancient forebears clad in animal skins, grunting and chanting through quaint solstice rituals because they were afraid the sun would disappear altogether. But the people who built Stonehenge, for example, were clever and knew their astronomy well. They weren’t afraid the sun would disappear. They were just depressed because it was so damn dark all the time. I bet they celebrated December 9th just like me. May it come soon.

A Space in Time

A bookstore, a weblog, a magazine, all these things take on the personality of their proprietor, and if that personality resonates sufficiently with your own, you find yourself coming back again and again, chuckling that someone should be able so consistently to amuse you, sight unseen. So it is for me, I find, with The Atlantic magazine. I can’t say exactly how they keep choosing articles that interest and entertain me, but they do. I will read anything by William Langewiesche, and he’s written the cover story this month about “unbuilding” the World Trade Center. Actually, the web version is an extract, and the magazine version is only one part of what will become a book on the same subject.

In the same issue, and fully available on the web, is beautiful lyrical essay
(“A Space in Time”) by Michael Benson about imagery from NASA’s various space probes. It’s long for an onscreen read, but it’s worth the effort. Near the end, he uses a long quote from Carl Sagan that I will include here. Carl says


In some respects, science has far surpassed religion in delivering awe. How is it that hardly any major religion has looked at science and concluded, “This is better than we thought! The universe is much bigger than our prophets said—grander, more subtle, more elegant. God must be even greater than we dreamed”? Instead they say, “No, no, no! My god is a little god, and I want him to stay that way.” A religion, old or new, that stressed the magnificence of the universe as revealed by modern science might be able to draw forth reserves of reverence and awe hardly tapped by the conventional faiths. Sooner or later, such a religion will emerge.

This echoes very much the teachings of Joseph Campbell, who pointed out that a healthy working mythology (religion) is one that puts you into accord with the universe as it is currently understood, not as it was understood by nomadic tribes in the Near East two thousand years ago. I’m with Carl. The religion we need is the one that lets us hug those improbable spacefaring robots from JPL. You go, God!