It's the first day of Fall - autumnal equinox science, videos, poetry, music

Here on the east coast, this year's autumnal equinox (wiki) occurs on September 22 at 3:20 pm EDT, according to the Old Farmer's Almanac. The equinox is the moment at which the sun appears to cross the celestial equator from north to south - or more simply, the first day of fall, with equal hours of light and darkness. In Latin, the word equinox is composed of two words meaning "equal" and "night."

I seem to remember that when I was a kid, the first day of each new season was always considered to be the 21st (of March for Spring, June for Summer, September for Autumn, and December for Winter). I guess it's more accurate now.

Mechanics of the equinox:


Science of the equinox. More here and here.

More science - why leaves turn different colors.

The 1869 version of Chambers' Book of Days has a post on the equinox (you may need to scroll down), including this interesting comment on the science of equinox-related weather:

As is well known, both the autumnal and vernal equinoxes are distinguished over the world by the storms which prevail at these seasons. The origin of such atmospheric commotions has never yet been very satisfactorily explained, but is sup-posed, as stated by Admiral Fitzroy, to arise from the united tidal action of the sun and moon upon the atmosphere; an action which at the time of the equinoxes is exerted with greater force than at any other period of the year.

Here's a 2 minute Nat Geo video:



No, you can't balance an egg on the equinox.

The falling leaves drift by the window
The autumn leaves of red and gold....
I see your lips, the summer kisses
The sunburned hands, I used to hold
Since you went away, the days grow long
And soon I'll hear ol' winter's song.
But I miss you most of all my darling,
When autumn leaves start to fall.

~Johnny Mercer, Autumn Leaves (see Nat King Cole singing this, below)

Mark Steyn has a long, comprehensive article on Autumn Leaves.

Nat King Cole singing it.

Here's a Fall Foliage Prediction Map.

Youth is like spring, an over praised season more remarkable for biting winds than genial breezes. Autumn is the mellower season, and what we lose in flowers we more than gain in fruits.

~ Samuel Butler

Autumn wins you best by this, its mute

Appeal to sympathy for its decay.

~ Robert Browning

Autumn is a second spring where every leaf is a flower.

~ Albert Camus

You expected to be sad in the fall. Part of you died each year when the leaves fell from the trees and their branches were bare against the wind and the cold, wintery light.

~ Hemingway (A Movable Feast)

To be interested in the changing seasons is a happier state of mind than to be hopelessly in love with spring.

~ George Santayana

The teeming Autumn big with rich increase,

Bearing the wanton burden of the prime

Like widowed wombs after their lords' decease.

~ William Shakespeare

It's not generally appreciated that perhaps the best-known of all works of baroque music, Le Quattro Stagioni ("The Four Seasons") (wiki) by Venetian composer Antonio Vivaldi (ca. 1675-1741), was first published with four Italian poems - likely by Vivaldi himself - that describe the several scenarios represented in the music. 

Below is Vivaldi's poem Autumn, and here's a performance of the third movement of "Autumn" in Venice's foggy Piazza San Marco:

Allegro

Celebra il Vilanel con balli e Canti
Del felice raccolto il bel piacere
E del liquor de Bacco accesi tanti
Finiscono col Sonno il lor godere

The peasant celebrates with song and dance,
The harvest safely gathered in.
The cup of Bacchus flows freely,
And many find their relief in deep slumber.

Adagio molto

Fà ch' ogn' uno tralasci e balli e canti
L' aria che temperata dà piacere,
E la Staggion ch' invita tanti e tanti
D' un dolcissimo Sonno al bel godere.

The singing and the dancing die away
As cooling breezes fan the pleasant air,
And the season invites each and all
To a sweet sleep, without a care.

Allegro

I cacciator alla nov'alba à caccia
Con corni, Schioppi, e canni escono fuore
Fugge la belua, e Seguono la traccia;
Già Sbigottita, e lassa al gran rumore
De' Schioppi e canni, ferita minaccia
Languida di fuggir, mà oppressa muore.

The hunters emerge at dawn
With horns, shotguns, and dogs baying.
The quarry flees while they give chase.
Terrified by the dogs and wounded by the guns
The prey struggles on,
But harried, dies.

The two revolutions, I mean the annual revolutions of the declination and of the centre of the Earth, are not completely equal; that is the return of the declination to its original value is slightly ahead of the period of the centre. Hence it necessarily follows that the equinoxes and solstices seem to anticipate their timing, not because the sphere of the fixed stars moves to the east, but rather the equatorial circle moves to the west, being at an angle to the plane of the ecliptic in proportion to the declination of the axis of the terrestrial globe.

~Nicolaus Copernicus