Hobbits Put an End to Summer in Detroit…Soon

This morning’s conversation took us (prematurely, I thought), to the End of Summer. Prematurely because it seems to me that the real summer had only shown precursors of itself, not a whole deck of its cards. But, of course, as Brigitte reminded me, we were now in September! And I should have known. In my childhood we were told that months ending in ber were generally of the colder sort.

So we to the calendars went. A few informed us that, indeed, in just five days Summer would be definitely Over. The Fall Equinox comes on September 23—at least here in Detroit. Another calendar calls it Beginning of Fall. Equinox, of course, means that day and night have the same length on this day. No wonder we kept wondering why the lights had to be turned on earlier and earlier.

All this, of course, is the bad news. So what’s the Good News? It is that September 22, thus exactly the last day of summer, is Hobbit Day. Those are the small humanoids created by the mind of R.R. Tolkien—Bilbo and Frodo Baggins. Now according to this Wikipedia source, there is a conflict here. According to Shire-Reckoning, the two birthdays fall between September 12 and 14. Our Gregorian calendar produces September 22—and only one day.

Good news, yes—but the usual scholarly not-so-is-so hullaballoo.

Autumnal Equinox Not

I rarely let an equinox (or solstice, for that matter) pass without at least a nod on this, of late much-neglected, blog. Today is one day after the autumnal equinox, as held by global consensus, but while nothing deters the sun from meeting its appointed rounds, humanity is more subject to pressures of the sort the sun, thank the Lord, never feels. Better late than never.

Above I say “by global consensus” because the equinox took place here (Detroit region) on Monday, the 22rd. But elsewhere in the world, say in Budapest, the city of my birth, it took place on Tuesday, the 23rd. Based on this site, which lists 145 major cities around the globe, a minority of 53 places experienced the equinox on Monday, a majority of 92 experienced it Tuesday. And I celebrate it Wednesday. Have rarely felt comfortable with results based on majority vote…

How it comes about that twice each year day and night have the same length is explained in this earlier blog post (link). I keep revisiting that post because celestial geometry is several levels above my mental pay-grade. So now we are a-march again, from equinox to solstice, with the days shortening but, I hope, our spirits gaining light.

The Dark, the Light

Some dreary element in modern life,

Its endless noise and ever-pointless strife,

Inclines me every autumn to observe

With something not unlike pious reserve

The movement of the sun, that best of clocks,

Its needle now on the Fall Equinox.

The Ecliptic

Today’s the day of the autumnal equinox. I understand it better this year than ever before. In the course of writing a post on the astrolabe for LaMarotte, I came to understand what’s known as the ecliptic. It is one of those maddening words. It reflects simultaneously two different points of view and two theories of the solar system. In one the sun goes around the earth; in the other we go around the sun. Here for instance is Webster’s definition of the ecliptic:

The great circle of the celestial sphere that is the apparent path of the sun among the stars or of the earth as seen from the sun: the plane of the earth’s orbit extended to meet the celestial sphere.

If it is a circle, why call it the ecliptic? It comes from creating eclipses, not the shape, although the earth’s orbit is ever-so-slightly elliptical, but not so much that you would notice. That path of the sun among the stars is the legacy of the geocentric view. It prevailed from the end of the Hellenistic era to the acceptance of Copernicus and Galileo in the West. The earth as seen from the sun is the other, the heliocentric view. Now, confusingly, virtually all pictures of the ecliptic have the earth smack in the center—so that the sun seems to be doing all the moving. That, of course, shows that our real orientation is egocentric. The ecliptic only interests humans because it explains the seasons on earth. An honest picture is the following:

The sun is squarely in the center. We do the traveling. The line we describe is the ecliptic. The sun is “in Aquarius,” as people say, meaning from our perspective; therefore it’s late January or early February. The circle of the zodiac was first determined by people waiting for sunrise. As soon as the first light appeared, they looked above that spot at the still dark sky. The constellation they detected right above the sun was the “house” in which the sun was rising. In July-August, when the earth will be where Aquarius is shown on the sketch, the dawn-watchers will see the constellation of Leo instead. Brigitte was born in Aquarius; I was born in Leo. Astrologically we complement each other. But, of course, neither Aquarius nor Leo ever move. Nor does the sun except around its axis. Anyone who could survive on the sun and live in a fixed spot there could divide his sun-day into twelve sun-hours by looking at the sky and reading off a sign of the zodiac. “See you no later than Sagittarius…”

But let’s now turn to the more usual illustration. An attractive one is show below from Wikipedia’s page on the Equinox (link). As expected, it shows the ecliptic circling the earth, whereas the earth is circling the sun, but never mind. What Wikipedia is doing here is depicting the first part of Webster’s definition above, the sun’s apparent path.

Notice next that the earth, which circles the sun following the ecliptic (the horizontal light-green ellipse), does so at a tilt to the ecliptic. This also means that our equator—and the “celestial equator” that we project from it (tilted dark-green oval)—are also at a tilt. As this diagram clearly shows, the ecliptic is therefore located below the equator through half the year and above it through the other half. And where we see the ecliptic, there we see the sun. Therefore the sun appears below the equator and then above it. The exceptions are two days of the year when the ecliptic makes its two crossings. Those days mark the autumnal and the vernal equinoxes; the sun is precisely over the equator. During those two 24-hour periods, day and night are of equal length. Note that the point of crossing is at the intersection of the vertical line drawn at 90° to our actual orbital plane, thus to the ecliptic.

Longest Day and Shortest Night

This year I greet the longest day well-prepared and without frustration thanks to a splendid illustration I managed to find on the website of the Yohkoh Outreach Project, an organization jointly sponsored by Montana State University and Lockheed Martin Solar and Astrophysics Lab. The site of the source is here. My frustrations arise (as earlier noted here) because my viscera really believe that the earth stands still and the sun moves. With this temperament, the usual explanation of an earth tilted on its axis tracing an elliptical path around a sun—and thus producing the seasons and the longs and shorts of days and nights—causes me bewilderment, vexation, and a sort of dizziness. I look at all the diagrams and can’t make heads or tails of them, because I’m looking at it all as from a spaceship, but actually I’m down here on the surface of the globe, right by the shores of Lake St. Claire. Yohko Outreach Project to the rescue. They’ve produced this simple, straightforward chart.

They’ve even put me in the center of it—see? And this chart, which shows the position of the sun as I would see it, from my own backyard, makes the solstices and the equinoxes crystal clear. The sun never dips lower to the south than at the Winter Solstice. After that day it rises daily to a slightly higher point in the sky. Thus the sun seems to be in motion, not only side to side, as from dawn to dusk, but also from the Winter Solstice up to the Summer Solstice. And it never goes higher than it does today. Tomorrow it reverses its course.

The name of this day, solstice, comes from the Latin for sun, sol, and sistere, to stand still. Its upward movement stands still today and reverses direction tomorrow. And it shall stand still again on December 21 and begin to rise again. Exactly in the middle of that process we have the equinoxes, coming and going. At the Winter Solstice we have the longest night, today the shortest, and in the middle night and day have the same length: equi nox.

Deep sigh of relief. Thank you Yohkoh Outreach Project. If only more of humanity would follow your example and do good things for the needy and the ignorant. It would be a better world. Now there must be at least a dozen people like me out there who’ll get something out of this post. So enroll me, too, on the side of the angels.

Equinocturnal Frustrations

Welcome Spring and so forth. I note that the weather, which cooperated magnificently for about the last two weeks of so-called Winter, refuses to smile today. It’s gray out there, cool, and humid. The weather perhaps shares my frustration at six month intervals when it’s time, once again, to celebrate the equinox. I understand this thing perfectly well in conceptual terms. The sun today is directly above the equator, straight up there in the perpendicular. As time now advances, that angle will become more and more acute, the sun appearing north of the equator until the summer solstice on June 21st. After that, back we go again, the angle increasing until the arrival in September—on the 23rd of that month this year—of the autumnal equinox. Thereafter the angle becomes obtuse (from our point of vantage), the sun beaming south of the equator to the delight of all Patagonians until December 21, the blessed winter solstice. Then it marches back again to March of 2011. I do get all this. Yes. But I can’t picture it properly. It’s all due to the earth’s tilted axis, isn’t it, which puts us now closer to the sun and now removes us farther away in wintertime. Every season—it’s amazing, actually, how this sort of thing fades from memory in six months’ time—I end up getting my ice-pick and an apple, and actually doing a kind of dance around a lamp holding the ice-pick at an angle until my geometrically dense brain finally gets it again. With that comes a moment of satisfaction, but the juices of frustration that came before—while trying to find good visuals on the Internet—linger long enough in my body to yield…well, a post “celebrating” the Vernal Equinox.