By Karl Egger from Pixabay
Who needs a time machine? I look out the window and see snow falling, and I am five again. Excited as the snow deepens, thrilled (still) to play in it, cozy in front of a fire afterward. The adult in me loves the way snow covers an often ugly world with pure loveliness—white satin draped over a plain dress. But how weird, that such a smooth blanket is made of sharp-edged crystals. That they are clear, yet look white, because their facets scatter sunlight. That each tiny wet splotch that falls on my reddened cheeks is like none other, yet they are all perfectly symmetrical.
I am not sure why snowflakes are all different and all perfect, and I am not sure I want to know. High school physics ruined rainbows irreparably. But Alan Lightman, a physicist who is poetic and humane, makes it feel safe to inquire. In his new book, The Miraculous from the Material, he uses his light touch to explain (without deflating their wonder) bioluminescence, birds, bubbles, fallstreak holes, fireflies, glaciers, hummingbirds, morning mist, Saturn’s rings, spider webs, spiral plants, shooting stars, scarlet ibises, volcanoes, waterspouts, even humans….
I turn to the chapter on snowflakes, and soon it is 1611, and Johannes Kepler is having an epiphany. If identical objects are packed together—the way a snowflake packs water molecules together—then geometry can be counted upon to “bring about certain symmetries and regularities.” As the water freezes into ice crystals, the molecules attach, clinging to one another in the cold….
Why, though, would such an elaborate, precise, six-sided symmetry emerge? Lightman wondered that at age fourteen, after he went outside with chilled glass slides, caught snowflakes, and looked at them through a magnifying glass. They were perfect, “exactly repeating each fragile branching and vagary six times around. How did a snowflake know to do that?”
Now, he knows. Each water molecule is made of one atom of oxygen and two of hydrogen, and “in the crystal lattice of a snowflake, the hydrogen atoms of each molecule bond to neighboring oxygen atoms.” When many are bonded together, “nature follows the minimum energy principle.” In other words, this new system, the snowflake, will be configured with the least possible energy, in order to be as stable as possible. And “for a group of water molecules in an ice crystal, the configuration of minimum energy has six-sided symmetry.”
I am still not sure why, but the result is so cool, I no longer care. The time machine zooms to 1936 and lands in a lab at Hokkaido University in Japan. Dr. Ukichiro Nakaya is about to create the first human-made snowflake. He will use a thoroughly dry hair plucked from a rabbit. Mounted inside a container of rising warm water vapor and falling cool air, the hair will sprout ice crystals along its length and get the snowflake started, just as tiny bits of dust do in the clouds.
Each of the six arms of the snowflake will grow in the same way. I am beginning to fathom the symmetry. But what of the variation? No two snowflakes are alike: science teachers wow us with that fact when we are little, and we never forget. “Could this variety keep up, with countless trillions of them dropping from the sky?” young Alan wondered.
It can, he learned, because snow crystals grow as cold water condenses, then refreezes, on a central speck of dust or ice, and “the growth pattern depends sensitively on the temperature and humidity of the surrounding air.” In the hour or two it takes to fall to Earth, wind and weather will shape and reshape the flake. Snow is, in other words, a lot like us: patterned, yet wildly different.
Snow lends itself to metaphor—and to oddly negative meanings. To snow is to deceive, and a flake is a ditz. When the word “snowflake” was first used to dis someone, I assumed it meant they would melt at the slightest challenge. In fact, it means that they are so self-impressed, they think they are unique and special. Still, those that precious do melt easily. Why, I wonder, when they are gifted with symmetry, a quality powerful enough to both astonish and soothe?
My first (and last) attempt at origami came in grade school, when, come December, we were taught to fold and fold and fold a piece of white paper, then snip. The unfolded surprise of that design felt revelatory. No child’s hand could have fashioned something so flawless without the help of those folds. Later I would learn about fractals, and the other crazy symmetries built into the universe. “The body craves symmetry,” a physical therapist once told me, reminding me to do the exercises on the unhurt opposite limb, too. Across cultures, we find the most symmetrical features the most beautiful.. Symmetry in architecture stuns and calms us—just look at the Taj Mahal. Symmetry in relationships balances the power and promises reciprocity. And mirroring, the ultimate symmetry, is our nervous system’s guarantee of empathy.
One can understand (what a relief) the mechanism behind snowflakes and still feel awe at their symmetry and endless variation. Water gathers on dust—and turns into so much more. In Smilla’s Sense of Snow, she knows the stuff intimately. “The way you have a sense of God,” she says, “I have a sense of snow.” Which, in its way, is also infinite.
Read more by Jeannette Cooperman here.
