Zoom: From Atoms and Galaxies to Blizzards and Bees: How Everything Moves (9 page)

Moreover, because of our planet’s oval shape—the midriff bulge that makes the earth’s diameter at the poles twenty-six miles less than its diameter at the equator—the middle is also where you stand closest to the moon and sun. Those romantic songs about a big tropical moon? They’re true—although the difference in size is just 1 percent. I wondered how many such science tidbits would be on display.

When I stepped out of the taxi (I loved saying, “Take me to the equator!”) I was nearly knocked backwards by the earsplitting sound of a band playing amplified salsa music, demonstrating the region’s well-known distrust of silence. The huge complex of plazas, wide granite steps, small gift shops, and open spaces where I stood was called Mitad del Mundo—the middle of the world. At its center, a multistory stone obelisk dominated the scene. A line set into the ground radiated from this monument and extended in two opposite directions for hundreds of feet. Here it was—the equator!

Outside Quito, Ecuador, the location of the equator is marked by an enormous five-story monument. It’s where our planet rotates at its very fastest. But the government built it in the wrong place.

Tourists, mostly from other parts of South America, straddled this line so that they could have their pictures taken with one foot in the Northern Hemisphere and the other in the Southern. With the deafening happy music and bright sunshine and colorful clothing and constant animated laughter in the thin air, this was a destination not of egghead subtlety for geography geeks but of carnival fun.

Except it isn’t really on the equator.

Long ago, in the days before GPS precision, the government built the monument in the wrong place. No brochure actually says so, of course; you have to learn it in a whisper from tour guides, who seem secretly thrilled to spill the beans. It didn’t appear as if anyone cared.

I quickly learned that the actual equator was up the road, a quarter mile north, and it was there that one could find the moving-water exhibits. Leaving this fancy official government complex with its grand stone structures and busy souvenir stalls, I hiked up the narrow highway until I reached a sign boasting that the real McCoy lay up a dusty dirt road. An arrow on the sign pointed the way. Panting in the thin air while jumping across potholes, I eventually came to a private museum, complete with its own painted equator line. The first lecturer I bumped into said that, yes, modern measurements prove that this is the true equator. I checked my handheld GPS and wasn’t at all sure she was right.

So far I’d learned only one thing: our planet has competing equators. Each gets many visitors. And I soon gleaned from my GPS and had it confirmed by an official that the true, honest-to-goodness equator is in neither place but rather lies another hundred yards farther north, on vacant grassland. If you’re looking for a business opportunity, buy this plot of land, have it paved, and then paint a third equator line. The crowds seem big enough to support lots of them.

The museum hosted nonstop demonstrations, most of which were ridiculous, including a woman in jeans standing at a folding table whose sole job was to balance an egg on a tray and then bilingually claim it can happen only at the equator. I finally reached my mecca, the exhibit that indeed drew twelve-person crowds every fifteen minutes—the supposed proof that water swirls down drains in opposite directions in each hemisphere. Impromptu variations of this demonstration are also held for tourists in numerous African villages. It has become the equatorial de rigueur “thing to do,” just as looking for the green flash has changed sunset gazing from the beautifully purposeless activity it used to be into a scientific endeavor.2

An attractive young woman leaned over a small, beat-up metal basin on legs and pulled the plug. The crowd watched the water spiral clockwise down the drain and into a big plastic bucket below. Then she and an assistant dragged the basin ten feet across the dubious equator line, the legs scraping cacophonously on the concrete floor while everyone winced. I wondered why they didn’t simply purchase a basin with wheels, since they obviously did this day in and day out. The two smiling Ecuadorans poured in the water again, the woman pulled the plug, and sure enough, the water spiraled down the opposite way. The crowd enthusiastically lapped this up (figuratively, of course) with appreciative murmurs. I had to admit it was pretty dramatic and persuasive.

After the group had moved on, and with the next group approaching, I collared the lecturer and quietly said, “May I do this demonstration myself?” Her enormous eyes met mine and showed a hint of alarm. She then held up a “wait just a moment” finger and scurried off to get the director.

Astride the equator, purportedly marked by a line of painted tile on the ground at left, an Ecuadoran woman demonstrates the way water swirls down the drain in a basin. It swirls in one direction on one side of the line and, after she drags the basin across it, in the opposite direction on the other side of the line.

In mere seconds, a twinkly, paunchy, middle-aged man materialized and offered his hand while I introduced myself in my best halting Spanish as a science writer. I might as well have identified myself as a clown, since his reaction was unrestrained laughter. I quickly learned that he was one of those rare fortunate people who find everything in the world amusing.

“Sure, you can perform the demonstration,” he said with a chuckle, but then he lowered his voice a bit, glancing at the next approaching group. “Just make sure to pour the water the correct way. Do it from the right when on the far side of the equator line”—and here he gestured as if emptying a pail sideways—“and then pour it in from the other direction when the basin’s on this side of the line. That’s the only way to make the water go down the way we want it to.”

In other words, they’re faking the whole thing.

“But this exhibit is a hoax!” I protested. Hearing this, the director laughed so heartily I suddenly wished I could keep him in my life forever. I think if he had somehow asked, I would have given him my daughter’s hand in marriage.

“Well, maybe it is!” he said with a giggle, “but we only claim that it’s a demonstration. If we don’t do it this way, it won’t work. And the tourists love it.” He glanced at a sign near the basin. “How else can we teach them about the Coriolis effect?”

The museum’s sign indeed explained that water goes down drains differently in each hemisphere as a result of what it called the Effecto Coriolis, which, the sign said, influences many other things, too. (It’s certainly influenced livelihoods in many enterprising African villages, where residents perform variants of the same bogus presentation.)

This whole business probably started in 1651, when the Italian scientist Giovanni Battista Riccioli published his book Almagestum Novum, which said that a cannonball’s trajectory should, strangely, curve to the right because of the spinning of the earth. This was actually a perilous statement, since Galileo had been hauled before the Inquisition just eighteen years earlier and forced to swear that Earth doesn’t move at all.

The freedom to speak openly about a spinning Earth had long been established by the time Gaspard-Gustave de Coriolis was born in 1792 in Paris, a few months before Louis XVI was guillotined. A science whiz kid, he placed second in the entrance examination for the prestigious École Polytechnique, became an engineer, and in his young years, despite chronic poor health, made major contributions to various scientific fields that involve motion, such as friction and hydraulics and water wheels.

By the time he reached the age of forty his brilliance was well known to members of the Académie des Sciences, thanks to his groundbreaking treatises on mechanics and motion. Coriolis coined and established the terms kinetic energy and work—in the physics sense—which are still universally used today. What would he think of next? He managed to surprise and delight the Académie in 1835 with a novel, perspicacious analysis of the math and physics of the game of billiards. (So that’s how the introverted Gaspard spends his spare time when his wife is out buying chaussures!) It was in that same year that he published the paper that would ultimately gain him sufficient fame for his name to be uttered daily by countless twenty-first-century equatorial tourists. Yet no one today recalls the paper’s title, since it seemed deliberately created as a cure for insomnia: “Sur les équations du mouvement relatif des systèmes de corps” (“On the Equations of Relative Motion of a System of Bodies”). In the second of its three sections, Coriolis spoke about the way moving objects reliably curve, though he never mentioned Earth’s spin or our atmosphere.

Scientists soon realized that Coriolis had explained perfectly why Caribbean hurricanes always rotate counterclockwise, why artillery shells veer away from their targets, and indeed why a perfectly balanced car speeding along on a level highway pulls, annoyingly, to the right. (An unknown number of wheel-alignment customers no doubt shell out millions of unnecessary dollars annually after being fooled by this effect.) In the early twentieth century, meteorologists started using the term Coriolis force to describe the vagaries of large-scale wind and storm systems.

And yet today, the Coriolis effect is routinely misunderstood. Flushing a toilet does not result in water spiraling down in any particular direction that corresponds to one’s location. The effect does, however, produce such oddities as robbing players of home runs, though Albert Pujols has not yet held up a clenched fist and yelled, “Damn you, Gaspard!” In ballparks in which the batter faces north or south, as they do in Dodger Stadium or Wrigley Field, a ball hit by a bat curves an inch to the right, so that it occasionally goes foul when absent Coriolis it would have stayed fair.

Unfortunately, in the great tradition of making physics as tedious as possible, most Coriolis explanations resort to discussions of inertia, reference frames, angular velocity, and something called Rossby numbers. A pity, since the Coriolis effect is actually easy to understand. Imagine two children riding on opposite sides of a merry-go-round, throwing a ball back and forth. If this carousel is spinning the same way Earth does—counterclockwise, as seen from above—then the child who throws the ball will observe it curve sharply to the right. Aiming it so that it can be caught by her friend would require no small amount of compensation.

Most of the early Greeks imagined that if Earth rotated, a person jumping up would come down in a different spot. But in reality, all objects partake of local motion. Say you live in Miami, where the ground and everything on it zips eastward at 933 miles per hour. Places north of you rotate more slowly; those south of you move faster. Now imagine you’ve purchased a potato cannon, which uses flammable gas or compressed air to hurl a spud tremendous distances. A half mile would be optimistic, but let’s say you’ve built a Big Bertha model that can throw a good Idaho a full degree of latitude, or sixty-nine miles, and you fire it toward the north. The ground a mere sixty-nine miles north of Miami moves eight miles per hour slower. The potato doesn’t know this, so while it’s in flight it’s also still going rightward, or eastward, at its initial Miami rotation speed. Meanwhile the ground beneath it moves more and more slowly as the flight progresses. Result: the starchy missile goes straight, but anyone on the ground sees it curve to the right.

Say you turn around and aim toward Key West’s boisterous Duval Street, to the south. The ground a mere one degree, or sixty-nine miles, south of Miami moves eight miles per hour faster than Miami does. So the south-heading spud flies over terrain that’s going more quickly than it is. It’s being left behind, and as a result it again appears to curve to the right, as witnessed by anyone on the ground.

So flying ballistic objects curve rightward whether they’re fired north or south (in our Northern Hemisphere, that is). Only those shot due east or west go straight. This is the Coriolis effect. If the potato hurtles at sixty-nine miles per hour and magically remains flying through the air for an hour, it will land fully eight miles to the right of where it’s aimed.

Barring a silo explosion, potatoes aren’t generally flying around us. But clouds and air masses are. Imagine a low-pressure storm, like a hurricane. Air tries to rush into it from surrounding higher-pressure regions. As it does so, it flies over ground that is rotating at a different rate than it is. The result is a right-turning tendency. Bingo: a circular storm spinning counterclockwise.3

That’s why hurricanes never form within 350 miles of the equator. There, not enough Coriolis deflection exists, since Earth’s rotation speed is rather uniform in the tropics. There, moving air steers a more or less straight path.4

The Coriolis force also explains why everyday winds in most of the United States blow from the west. Air rises up because of equatorial heat and then heads toward the North Pole. Doing so, it deflects to the right. Voilà: our prevailing westerlies.

Now consider your toilet, a form of meditation strongly sanctioned by the likes of Kohler and American Standard. Naturally, the waters on opposite sides of the bowl partake of Earth’s rotation. The water on the south side of the toilet moves faster than the water on the north side if you live in North America, Europe, or Asia. Shouldn’t this give the water a push so that when you hit the lever it spirals down the drain counterclockwise?

Let’s do the math. Turns out the difference in Earth’s spin speed between one side of a twelve-inch bowl and the other is the same as the speed of the hour hand on a kitchen clock. The hour hand. Basically stationary. It’s not zero, but it’s obviously not going to give ten pounds of liquid any kind of shove. Instead, the direction of swirl depends solely on the direction of the incoming water, dictated by all those little holes concealed beneath the lip of the porcelain. In a basin or tub, the drain-swirl direction is determined by the basin’s or tub’s levelness.

Gaspard-Gustave de Coriolis never got involved in any of this. He didn’t even have flush toilets. In fact, though he became a distinguished professor of math, physics, and mechanics and ultimately director of studies at the prestigious École Polytechnique, he never lived to see his name widely attached to the effect he discovered. As in the case of Dorian Gray, his handsome, clean-shaven appearance was deceiving, for his body suffered perennial poor health. He found his energy rapidly diminishing in the spring of 1843 and died late that summer, at the age of fifty-one.