Today is the autumnal equinox - science, videos, quotes, poems, Vivaldi and Copernicus

Mechanics of the equinox:

Science of the equinox. More here, here and here (this article is from 2012, so the time is wrong).

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)

Here's Nat King Cole singing Autumn Leaves:

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

The leaves are falling, falling as from way off,
as though far gardens withered in the skies;
they are falling with denying gestures.
And in the nights the heavy earth is falling
from all the stars down into loneliness.
We all are falling. This hand falls.
And look at others: it is in them all.
And yet there is one who holds this falling
endlessly gently in his hands.
~Ralph Waldo Emerson, Autumn

O Autumn, laden with fruit, and stained
With the blood of the grape, pass not, but sit
Beneath my shady roof; there thou may'st rest,
And tune thy jolly voice to my fresh pipe;
And all the daughters of the year shall dance!
Sing now the lusty song of fruit and flowers.
~William Blake

Season of mists and mellow fruitfulness,

Close bosom-friend of the maturing sun;

Conspiring with him how to load and bless

With fruit the vines that round the thatch-eaves run;

To bend with apples the moss'd cottage-trees,

And fill all fruit with ripeness to the core;

To swell the gourd, and plump the hazel shells

With a sweet kernel; to set budding more,

And still more, later flowers for the bees,

Until they think warm days will never cease,

For Summer has o'er-brimmed their clammy cells.

~John Keats

It was one of those perfect English autumnal days which occur more frequently in memory than in life.

~P. D. James

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

Autumn's earliest frost had given

To the woods below

Hues of beauty, such as heaven

Lendeth to its bow;

And the soft breeze from the west

Scarcely broke their dreamy rest.

~John Greenleaf Whittier

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

~George Santayana

The day becomes more solemn and serene,

When noon is past - there is a harmony

In autumn, and a lustre in its sky,

Which through the summer is not heard or seen,

As it could not be, as if it had not been!

~Percy Bysshe Shelley

The teeming Autumn big with rich increase,
Bearing the wanton burden of the prime
Like widowed wombs after their lords' decease.
~William Shakespeare

Today (22 September) at 10:29 in the evening (EDT), we will mark this year's Autumnal Equinox, 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. It's not generally appreciated that perhaps the best-known of all works of baroque music, Le Quattro Stagioni ("The Four Seasons") 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