Zoom: From Atoms and Galaxies to Blizzards and Bees: How Everything Moves (10 page)

We’ve seen that although our planet’s motion is not manifested in the water swirling in toilet bowls, it is indeed manifested by the west wind blowing daily on our cheeks. But is there any way we can be sure, right here in this room, that we live on a spinning ball? This was an issue that obsessed yet another Frenchman, Léon Foucault, born in Paris in 1819.

Foucault made the first-ever accurate determination of the speed of light, using a polygonal mirror that spun eight hundred times a second. He and another Frenchman were also the first to photograph the sun, in 1845. Back in those days of daguerreotypes, very long exposures were required even for such a brilliant object, and Foucault used a clock drive, a geared mechanism hung below a telescope, to track the sun as it crossed the sky. It was while using this common astronomical device that he noticed that its suspended governing weight, which swung like a pendulum, seemed to gradually change its orientation. With a sudden shock, Foucault realized—a sacre bleu moment—that it wasn’t the pendulum’s path that was changing, it was the ground beneath the telescope. The pendulum was actually maintaining a near-constant plane of swing relative to the universe.

The son of a publisher, Foucault was an innately gifted teacher and popularizer. He wasted little time constructing an enormous pendulum fashioned of a massive sixty-two-pound iron ball suspended from a wire more than twenty stories high. He then set it swinging in the Panthéon in Paris. (Who does things like that today?) A sharp metal point welded onto the bottom of the ball scratched a line in the sand he had spread on the floor. Crowds watched as the line shifted, proving that the earth was rotating under the apparatus. Here was the first irrefutable demonstration of our spinning world that could be performed within a single room.

Not only was this pendulum endlessly duplicated and immensely popular throughout the late nineteenth century, it remains so today—even in our age of fast-evolving technology. At a time of severe budget constraints in 2007, when the State University of New York built a new science building at its most prestigious honors college, Geneseo, they scarcely had funds for frills. Yet they nonetheless installed a large brass Foucault pendulum in the lobby, which swings back and forth to greet all visitors.5

Despite the fact that he was homeschooled, and despite the fact that he disappointed his family by abandoning his original plan to enter the medical profession (he had a squeamishness about blood that bordered on phobia), Léon Foucault changed the world. It was he who coined the word gyroscope, perfected telescope mirrors, and revealed the vagaries of light speed, including the way it slows down under certain conditions. Most of all, he gained global renown for his dramatic pendulum, proof of our whirling planet, for which he received the prestigious Copley Medal of the Royal Society in 1855—that era’s equivalent of the Nobel Prize.

Sadly, Léon Foucault fared no better than Coriolis in the longevity department. Mirroring a dramatic swing of one of his pendulums, at the peak of his fame and to the horror of his family and friends, he suffered a sudden and startling physical deterioration that was probably the result of a rapidly progressing form of multiple sclerosis. He died in 1868, at the age of forty-eight.

If you manage to overlook his name near the pendulums oscillating nonstop at science museums throughout our spinning world, you might notice it among the seventy-two names of science luminaries—including Coriolis—inscribed by Gustave Eiffel on the first balcony of his tower.

The Unhurried Riddles of Snow and Ice

Trust not one night’s ice.

—GEORGE HERBERT, JACULA PRUDENTUM (1651)

If you look at a map of Alaska and stick a pin right in the center, you’ll be close to Fairbanks. In China or India, Fairbanks would be called a town, maybe even a large village. But in this ultra-low-density state, with an average of approximately one person per square mile, Fairbanks officially earns the “city” moniker even though it has a stoic population of merely thirty thousand.

It was late winter, and a short drive on tires that went thump thump thump for a while—their flat spots were caused by the rubber freezing during overnight parking—took me away from all traces of Fairbanks. It’s easy to leave civilization behind in Alaska. In 2013, taking along a tour group of forty-four adventurers, I’d been heading east for nearly two hours, toward the Yukon. But the sparsely traveled road never makes it there. Or anywhere close. It ends at Chena Hot Springs.

The aurora borealis dances above many places, but nowhere does it appear more often than in Chena, where it is particularly striking against the dark, inky skies. The reason is simple. All auroras are merely small sections of an enormous glowing doughnut that surrounds Earth’s magnetic poles. As we’ve seen, the northern pole lies adjacent to a barren Canadian island in the territory known as Nunavut. Whenever solar emissions get particularly intense, the auroral oval widens and expands southward. Then people in Wisconsin, Pennsylvania, and, in extreme cases, even Florida get to see it from their backyards.

That happens every few years. More usually the aurora borealis forms a steady ring that hovers over the middle of Alaska. Right in the Chena Hot Springs–Fairbanks area. For Fairbanksans, the aurora is more familiar than deer ticks are to northeastern suburbanites.

This was my sixth wintertime trip to this region. I had been the aurora lecturer for an Astronomy magazine tour group back in the late 1990s and early 2000s, and now, with solar activity once more on the rise, I was doing it again for a private science company. But this year I had embarked on an additional quest for a specific polar experience: hidden natural motion in the white wilderness.

An aurora shimmers over central Alaska in March 2014. Though its motion seems leisurely, this light show is the result of broken atom fragments from the sun striking us at 400 miles per second. (Anjali Bermain)

Alaska’s vast frozen landscape includes quirky dynamic aspects that lie beyond most people’s ken. But this wasteland’s animation really starts with the simplicity of ice.

Flowing rivers brake to a screeching halt in October. In Alaska, this creates flat white highways that last through April, allowing isolated villages to be reached overland. When that happens the landscape metamorphoses into a motionless still life. Thus, for most of the year, the polar realm resembles the desert.

Water’s change from liquid to solid requires eighty calories of energy for each gram of ice the size of a sugar cube. Water reaching thirty-two degrees Fahrenheit isn’t enough to do the trick, though. Water needs a push, an extra bit of frigid encouragement, to turn solid. Moreover, ice is not a good heat conductor, which means it is a poor cold conductor, too, so it thickens only gradually. To use real numbers, if the air temperature stays at an unwavering fourteen degrees Fahrenheit, studies show that ice will form and grow to four inches thick in two days. That’s the minimum recommended thickness for ice fishing or other activities pursued on foot.

How much time to double that to eight inches? Not another two days but rather a full extra week. Ice starts fast but then takes a go-slow approach. It requires an entire month more to achieve the fifteen-inch thickness that can support the weight of cars.

Resembling souvenir snow globes, the scene in Fairbanks can look Christmassy even in May and September, for the city has just three snow-free months. But here and everywhere else, an odd cloud dance has to happen for snow to materialize. Water droplets don’t simply freeze just because the temperature falls below thirty-two degrees Fahrenheit. First, several water molecules have to collide before a potential ice structure can begin to form. A single molecule cannot freeze.

Second, if the droplets are pure water, the ice-crystal process is reluctant to get under way at all. It won’t happen anywhere near the freezing mark. As if bureaucratic red tape is gumming up the process, ice won’t form unless the temperature reaches seventy-two degrees below the freezing point. Forty below zero.1 So for ice or snow to materialize at a more reasonable and common temperature, the cloud’s droplets need a seed or nucleus around which to grow. Since air normally contains lots of tiny floating debris, this is usually no problem. But you’d never guess what the best ice-generating specks might be.

Germs! A droplet readily freezes into a crystal around a living airborne microbe, a bacterium, at any temperature below twenty-eight degrees Fahrenheit. They’ll form around a tiny speck of floating clay (kaolinite) a bit more reluctantly and only if it’s colder than twenty-five degrees Fahrenheit. And if all they have are specks of silver iodide, the compound used in cloud seeding, they’ll start to make crystals below twenty degrees Fahrenheit. But germs are the most common snowflake starters and lie at the heart of 85 percent of all flakes.2

So next time you gaze at a lovely snowstorm, inform your favorite germophobe or hypochondriac that living bacteria sit shivering in most of those untold billions of flakes. Then hand him or her a snow cone or organize a catch-a-snowflake-on-your-tongue party.

Once the ice-forming process is started, more molecules join the party, and the crystal grows. It can ultimately become either a snowflake or a rough granule of ice called by the odd name graupel. A snowflake contains ten quintillion water molecules. That’s ten million trillion. Ten snowflakes—which can fit on your thumb tip—have the same number of molecules as there are grains of sand on the earth. Or stars in the visible universe. How many flakes, how many molecules fashioned the snowy landscape I was observing as I drove east? It numbed the brain.

The white surface stretching off into the distance was of course cold, but even beneath it the ground is permanently frozen here. This permafrost is ubiquitous north of the Arctic Circle, just over a hundred miles from Fairbanks. In the southern two-thirds of Alaska it’s common yet spotty. It may not start until a depth of thirty feet in some places, while a few yards away the permafrost lies at the surface.

Residents have no choice but to build their homes, roads, pipelines, and schools on this permafrost. The results are often disastrous. A drive along many Alaskan roads reveals houses sagging pathetically. Inside, floors slant so dramatically that one can almost slide from the bedrooms at either end toward the kitchen in the middle. On this trip, one dispirited native lamented the astronomical costs he was facing, first to jack up the entire building and then to try to create flowing air beneath it so that the frost can reestablish itself and remain year-round. The problem is unpredictability. The ideal technique—building on stilts so that cold air ventilates beneath—usually preserves the permafrost and keeps the house level.

Throughout this vast state in summer, the top few feet of permafrost melts, but the water has nowhere to flow. This creates billions of stagnant pools of various sizes that are perfect mosquito breeding grounds. It’s a nightmare. Slap your arm on any random spot between May and August and you will kill ten mosquitoes.

The slow-motion drama of heaving and settling ice and the homes built on them plays out all across Earth’s frozen wastelands. Meanwhile the weight of countless snowfalls typically compacts everything below them into ice. In places, this cobalt-blue ice remains rock-hard for tens of thousands of years. We know this from analyzing bubbles of trapped air, which reveal the contents of our atmosphere as it was long before humans made fire or untold domesticated cattle belched methane.

Meteorites plow into the snow, become entrapped, and emerge only when that ice layer has completed its mysterious slow journey down, sideways, and eventually back up to the surface. In the vast parts of Antarctica, where ordinary terrestrial rocks have no business lying on the snowfields, researchers in snowmobiles enjoy gathering up any solitary stones they find, knowing they’ve probably just snagged a valuable visitor from space using this no-brainer method. The famous black Antarctic meteorite ALH84001, which originally came from Mars, lay conspicuously on the snowy surface of the Allan Hills region when a snowmobiler found it in 1984. It had resurfaced sixteen thousand years after its impact and initial burial, having been subjected to remorseless icy, hydrolic cycles of pressures, releases, and movements in various directions unchronicled and unknowable by anyone.

Slow motion is ice’s solemn oath. Even its beginnings are leisurely, since snow typically falls at three miles an hour—the same speed a person walks. But if the snow compresses over a glacial field, it naturally partakes of that ice sheet’s even slower creep to the sea. These flowing ice rivers move anywhere from ten feet to one hundred feet a day, depending mostly on the slope of the land. Typical glaciers move a foot an hour, just barely too slow to notice.

Yet beneath much of Alaska’s immobile snowy landscape is lively movement. It’s an entire biological world. This is the subnivean realm.

You don’t need to be in Alaska to experience the subnivean universe or even to fall in love with the word. In most of the United States and Europe, the winter landscape—so seemingly motionless—hides constant animated activity on the part of small mammals, including voles, mice, and lemmings. They not only adapt to the snow cover but also rely on it for their very survival. They scurry along wide corridors an inch or two high in the gap between the ground and the bottom of the snowpack, a gap formed after the snowpack contracts a bit.

This region, illuminated diffusely from above in seemingly perpetual twilight, enjoys an air temperature around the freezing point once the snow cover is more than a half foot thick, thus creating insulation against the frigid air above. This subnivean system of open spaces and tunnels lets these mammals move unseen by many predators, although foxes and owls can hear the scurrying and usually know exactly where to pounce.

Everything seems motionless in this winter scene. Yet under the snow, in a gap between its lower boundary and the ground, lurks the subnivean realm, where small mammals are engaged in constant activity.