By Dr. Robert Thorson
Last week, I suggested getting rid of the U.S. penny. This week, I’m suggesting we get rid of fall. I do not propose to rearrange the tilt of the Earth or its revolution around the sun. Instead, I propose we replace the term “fall” in common speech with the much more accurate label “autumn.”
Fall is the short version of Middle English fallen, from the Old English feallan, from the Indo- European phol. This is about gravity. The connotation, according to my dictionary, is “to drop without restraint,” often suddenly.
Acorns drop without restraint, pinging with percussion on resilient objects beneath. Leaves do not. They flutter. They float. They drift, buoyed up by the invisible stiffness of air. From the Latin autumnus, autumn is a season commanded to be three months long by our clockwork universe. In the northern hemisphere, autumn occurs between the equinox in September and the solstice in December.
Deciduous leaves do fall during autumn. This year, the gravitational fall spanned no more than a few weeks of the astronomical autumn, with the vast majority of leaves coming down on a few days on either side of Thanksgiving. Luckily, autumn is splendidly slow; a prolonged season of transformation defined more by its color than its weight. For the mammal in me, it’s about the gathering of food reserves. For the human in me, it’s about the gathering of emotional resolve.
“Fall foliage” tours are popular in New England, especially to the north. What’s being advertised here with respect to physics is not the spectacle of gravity, but the spectacle of visible radiation.
Travel agencies don’t offer “fallen foliage” tours because, by then, the leaves are already on the ground, the colors fading fast. I suspect that part of the popularity of booked foliage tours involves the sheer uncertainty of it all, akin to the pleasure of buying a lottery ticket and hoping for the best.
Henry David Thoreau wrote practically nothing about the colors of autumn. Instead, he focused his attention on the gradual seasonal change, especially on the surface of Walden Pond, which “betrays the spirit that is in the air.” This is the way I feel about autumn colors, which have nothing to with gravity, but everything to do with meteorology, integrated across the season.
Leaves turn from green to brown when deciduous trees make the decision to let their leaves die, rather than struggle to save them through the winter. During the slow death of each leaf, the green pigment called chlorophyll fades. This tonal fading reveals the yellow and orange pigments that were there all along, but previously masked by the darkness of green.
The brilliant red colors are far more volatile. They’re caused by a pigment called anthocyanin, the same one that paints rose hips lipstick-red on sand dunes and apples dusky red in orchards. Anthocyanin, which easily overshadows the yellow, blazes only when the leaves retain enough sugar. This happens most beautifully when there’s an ideal mix of sunny days and cool, dry nights. Thus it is that the autumnal spectrum betrays the spirits that are in the air.
Act II is the actual falling. This too betrays the spirits in the air. The drift of leaves gives us direction. Their individual spin and collective whorls tell of turbulence at different scales. Their flutter manifests the finite strength of air. The best part of this second act is not the fall itself, but what fall reveals, the gradual brightening of what had been a gloomier and more closed-in sky. I need this reprieve of light to endure the darkening days this side of the solstice.
Act III takes place on the ground. Initially, the leaves blow sideways like sand on the beach, back and forth from yard to yard. Gusts clatter leaves together in fast staccato. Next is the pleasant audible rhythm of raking and the annoying whining of leaf blowing. As autumn continues, however, the leaves become sodden and soft. Just before freeze-up, they become a carpet of quiet.
To name the theater of autumn after its briefest act is worse than misleading. It associates gravity with a season that has more to do with light.