To say that water is essential hardly covers it.
—Dr. Richard Wolfenden,
professor of biochemistry,
University of North Carolina at Chapel Hill
EVERYONE IS AN EXPERT ON WATER.
We all know how it feels to be so grungy that nothing but a good shower will make us feel better. We know how it feels to be so thirsty that only water will really satisfy us. And we know exactly how the water will taste—really, how the water will feel—going down, in that first swallow.
We know how light shines through water in a drinking glass or a swimming pool. We know how to anticipate the arc of water from a drinking fountain, and the force of a wave at the beach, although we can be surprised by both.
You know exactly how hot you want the shower spray to be, and how strong, before you step under it. When you dip a foot or a hand into the swimming pool, you know what temperature will make diving in seem irresistible, and what temperature will give you a little shiver.
You know how far to turn on the outside spigot to get exactly the right spray from the lawn sprinkler. You remember how it feels to race through that sprinkler, and what it’s like to have your big sister turn the hose on you in the backyard. We know what it’s like to brace briefly before the dash through the rain from the office door to the car.
We know the sharp smell of rain misted through the air after a summer downpour. Snowy air has its own smell, chilly early morning fog has its own smell, the humidity in Key West has its own smell.
Water speaks a whole range of languages, specialized and universal, utilitarian and poetic and romantic. Sometimes they are all talking at once. The wind across the surface of a lake or bay writes clearly on the waves; the changing hues of aqua off Cape Hatteras or Cape Town are their own kind of depth sounding. Lake Superior is a dazzling turquoise that is memorable in part because it seems to belong not to a chilly northern lake but to a tropical beach.
The feel of water is as familiar as the feel of our own skin. The playful, sparkling flow of a creek through our fingers, the thrill of planing a hand across the top of the water over the side of a speedboat. The trickle of a single bead of sweat down your nose during a run, the feel of snow that gets inside your parka melting down your back, the surprisingly hard slap of swimming pool water when the dive becomes a belly flop, the faint rocking motion of a bunk on a sailboat at anchor.
Water is sprinkled through our memories, from junior high biology class to our honeymoons. It’s easy to remember what it’s like to use an eyedropper to squeeze a single, fat drop of water onto a microscope slide, and how big that drop looks, like an overstuffed couch cushion. It’s hard to learn to read the meniscus of water measured in a graduated cylinder. It’s hard to forget the first sight of Rome’s Trevi Fountain, or Las Vegas’s Bellagio fountain, or the fountain from your infant son, having his diaper changed. We know the shapes of shifting light that water makes on the bottom of a swimming pool (although we may not know they are called “caustics”). And we know the captivating power of a waterfall, how in the end you have to simply pull yourself away from watching the cascade, which manages to be always the same and always different, never boring.
We are all experts on water.
And yet, for all our intimacy with water, we actually know almost nothing about it—about water itself. Water is as potent in our daily lives as gravity, but also as mysterious.
For most of us, even the most basic questions about water turn out to be stumpers.
Where did the water on Earth come from?
Is water still being created or added somehow?
How old is the water coming out of the kitchen faucet?
For that matter, how did the water get to the kitchen faucet?
And when we flush, where does the water in the toilet actually go?
The things we think we know about water—things we might have learned in school—often turn out to be myths.
We think of Earth as a watery planet, indeed, we call it the Blue Planet; but for all of water’s power in shaping our world, Earth turns out to be surprisingly dry. A little water goes a long way.
We think of space as not just cold and dark and empty, but as barren of water. In fact, space is pretty wet. Cosmic water is quite common.
At the most personal level, there is a bit of bad news. Not only don’t you need to drink eight glasses of water every day, you cannot in any way make your complexion more youthful by drinking water. Your body’s water-balance mechanisms are tuned with the precision of a digital chemistry lab, and you cannot possibly “hydrate” your skin from the inside by drinking an extra bottle or two of Perrier. You just end up with pee sourced in France.
In short, we know nothing of the life of water—nothing of the life of the water inside us, around us, or beyond us. But it’s a great story— captivating and urgent, surprising and funny and haunting. And if we’re going to master our relationship to water in the next few decades—really, if we’re going to remaster our relationship to water—we need to understand the life of water itself.
One of the great scientific students of water is Dr. Richard Wolfenden, alumni distinguished professor of biochemistry at the University of North Carolina at Chapel Hill. Wolfenden, seventy-five, is a researcher who has spent much of his career studying how water shapes our body chemistry, inside our cells. Proteins in our cells manage every element of human life, and the key to the effectiveness of proteins is the way their long chains are folded into intricate and precise shapes, like tiny molecular origami. Proteins only work—which is to say, everything about our bodies only works—if the folding is exactly correct. That folding, it turns out, is engineered by water. “Proteins know how to fold up because they have the rules written into their atoms,” says Wolfenden. “And the rules are entirely a reflection of how eager that part of the molecule is to get away from water or to cling to water. To say that water is essential hardly covers it.”
Wolfenden has the e-mail address water@med.unc.edu because, he says, “of this never-ending interest in how many things water influences.” His North Carolina license plate used to read “DROPLET”; he’s switched to “HUMID.” “That matches North Carolina,” he says.
Asked if he is optimistic about our future relationship to water, Wolfenden is silent for a moment. Then he says, “I think our relationship to water is going to be one of the deciding things of the next century. I don’t think water’s in any trouble. But we might be.”
NO EXPRESSION IN COMMON USAGE is as thoroughly wrongheaded as “dull as tap water.” One thing water is not is dull.
Given our intimacy with water, our dependence on it, and water’s apparent simplicity—“H2O” is surely the best-known molecular formula in human consciousness—the surprising thing is how many surprises the story of water contains, and how many flat-out mysteries. Often the two go hand in hand.
The oldest rock discovered so far on Earth—in northern Quebec—is 4.28 billion years old.1 That’s an old rock—it’s getting close to the age of the solar system itself, estimated at about 4.6 billion years.
But turn on the faucet in the bathroom to brush your teeth, and the water pouring out is probably just a bit older than Canada’s old rock. Scientists don’t agree on the precise age of the water on earth, but it’s certainly 4.3 or 4.4 or 4.5 billion years old. It’s one of the more astonishing things about water—all the water on Earth was delivered here when Earth was formed, or shortly thereafter. The water around us is original equipment—it was included with the planet itself, in the first 100 million years or so. There is, in fact, no mechanism on Earth for creating or destroying large quantities of water. What we’ve got is what’s been here, literally, forever.
Of course, everything we’ve got on Earth was, fundamentally, delivered as original equipment, from our cars to our granite countertops. It’s all made out of the raw material around us—the atoms and molecules of which Earth, and everything on it, are composed. But here’s the difference: Even the granite kitchen countertops come from rock that has been heated, pressed, and completely remade deep in the crust of the Earth.
All the water on Earth came from space in exactly the form it’s in now: H2O. Water not only came from space, it was created out in space. It is, in fact, cosmic juice, formed hundreds of millions, or even billions, of years before the solar system itself.
Once you understand the lineage of water, you realize that the ads touting Evian (“born in the French Alps”) and FIJI Water (“untouched by man”) dramatically understate the case. It is remarkable the space and time that routine glass of ice water has covered, in order to soften your thirst.
Here’s a brief exchange with William Latter, a Caltech research astronomer specializing in studying the interstellar medium, the dust clouds between stars that will eventually condense and form new stars.
Q: So all the water on Earth came from an interstellar cloud somewhere in the Milky Way?
LATTER: Exactly right.
Q: And it was formed one molecule at a time?
LATTER: Exactly.
Q: There’s a lot of molecules of water here.2 It seems like that would take some time.
LATTER: The amount of time involved is millions of years, or depending on what we’re talking about, it’s billions of years. The universe is very old. It has time to do things, and space.
The universe has time and space to do things, like a master vintner, allowing the oxygens and hydrogens to find each other, crafting each H2O molecule, patiently creating a planetful of water, always with exactly the right balance between freshness and maturity.
Gary Melnick is a senior astrophysicist at Harvard University’s Center for Astrophysics who has spent years using orbiting telescopes to study star formation and water in space. He was part of the team that in 1997, using the European Space Agency’s Infrared Space Observatory (ISO), discovered an interstellar spring of water of astonishing scale.
They pointed the ISO telescope at Orion, a constellation that is quite easy to spot with the naked eye on a clear night. The stars of Orion are part of our own Milky Way, and one shining spot in Orion—the middle dot in Orion’s sword—is in fact not a star but a massive, glowing cloud of gas and dust, the Orion Molecular Cloud. That cloud is the kind where new stars form, condensing out of the hydrogen gas.
“Orion is the closest region to Earth where massive stars are being formed,” says Melnick. The full cloud of hydrogen, which looks to the eye like just that one dot in Orion, is of such vast scale that it is giving birth to thousands of stars at once.
When Melnick and his colleagues used the telescope to look at part of the Orion Molecular Cloud, he says, “What we found was that there is enough water being formed sufficient to fill all of Earth’s oceans every twenty-four minutes.”
As the stars coalescence and collapse in on themselves, they send shock waves out through the clouds of gas, which contain lots of loose hydrogen and oxygen. When the shock waves slam the hydrogens and oxygens into each other, they often form water. Hydrogen, for the record, is the most common element in the universe; oxygen is the third most common.
The result, right there in the sword hanging from Orion’s belt, is a water factory that is making the equivalent of all the water on Earth, sixty times a day. Have a look at the Pacific Ocean, or the Atlantic Ocean, or something small like Lake Michigan, and think about creating just that much water three times an hour—the scale is really almost hard to credit. All the water on Earth, sixty times a day? That’s one swampy patch of the Milky Way.
Not quite, says Melnick, with the bemusement of a guy used to thinking in cosmic distances that the rest of us find literally unimaginable. “The cloud is creating enough water molecules every twenty-four minutes to fill all of Earth’s oceans,” says Melnick. “The density of the water, well, it’s not like if you were floating out there, you’d get hit with a bucket of water in the face or anything.”
While the cloud is making sixty Earth waters every twenty-four hours, it is doing it across a span of space 420 times the size of our solar system.3 As a place in space, the Orion Molecular Cloud is pretty gassy, pretty dusty, and very wet. For us, not so much. Even the dustiest parts of the cloud—the places with the most particles—are emptier than any vacuum that people can create on Earth.
“It is the same as cool mist,” says Melnick. “It’s just a lot less dense.” A mist of water so fine that it resembles the emptiest space you can possibly imagine. But a lovely cool mist of space water, nonetheless. And a productive mist. In the fourteen years since its discovery by Melnick and his colleagues, the cloud has created enough water for about 300,000 planets as wet as Earth.
Water forms in interstellar clouds in another way, equally familiar and equally alien. The hydrogens and oxygens literally mate on the surface of tiny grains of dust that are part of the interstellar clouds. In the cloud, says Melnick, “hydrogen hits the dust grains quite frequently. And every once in a while oxygen will hit the dust grains too, and linger.”
What happens next isn’t quite clear, says Melnick, “but somehow the hydrogen finds the oxygen and forms OH. Then another hydrogen finds it and forms H2O.” The new water molecules form a thin coating of ice on the dust grain, like what you find on ice cream that’s been in the freezer too long.
A water molecule is about one-thousandth the width of one of these dust grains, so the dust grain can carry millions of water molecules if the hydrogens, the oxygens, and the dust grains can find each other. “They could form multiple layers of ice over time,” says Melnick, “if they are left undisturbed.”
And sometimes the water from the cool mist lands on a dust grain, and clings. “If the dust grain is cold, in almost all of those cases, the water will stick to it and not come off,” says Melnick, “just the way your tongue sticks to a cold pole in the middle of winter.”
Your tongue, of course, is covered with saliva that is 99.5 percent water, water which was itself once floating around in interstellar space, perhaps frozen onto a dust grain.4
And that’s it, as far as the astrophysicists and the astrochemists understand it at this point: All the water on Earth—the thunderheads, the snow-covered ski slopes, Old Faithful, and the current of the Mississippi River—started out as the finest mist, the smallest ice cubes, drifting around inside an interstellar dust cloud.
In general, there is no dispute about that.
Here’s the mystery. Scientists don’t actually know how that water gets from the interstellar cloud to Niagara Falls. And perhaps most startling of all, they don’t know how much water there is on Earth.
ONE OF THE GREAT MYTHS about water is that it is the most common substance on Earth. Indeed, you can Google search “the most common substance on Earth,” and water pops up repeatedly. The Earth’s surface is 71 percent covered in water, and water is the primary force shaping every element of the character of the planet—the geology, the weather, the range and variety of life, the planet’s gleaming profile in space.
But unless you’re playing a children’s game in which you mean that water is, quite literally, the most common substance sitting on the surface of the Earth (as opposed to the most common substance making up Earth’s composition), then the amount of water on the planet’s surface is trivial in every way except its impact. The total water on the surface of Earth (the oceans, the ice caps, the atmospheric water) makes up 0.025 percent of the mass of the planet—25/100,000ths of the stuff of Earth. If Earth were the size of a Honda Odyssey minivan, the amount of water on the planet would be in a single, half-liter bottle of Poland Spring in one of the van’s thirteen cup holders.5
Put another way, if the oceans on Earth were as deep, in relative terms, as the skin on a typical apple is thick, they would average ten kilometers deep instead of four kilometers, and all the land on Earth would be inundated except the planet’s tallest mountains.6
Once you actually pause and appreciate how fine the film of water enveloping Earth is, water’s impact is even more dramatic.
What’s more, most of the water on Earth is not the water we’re familiar with. Most of Earth’s water is not the water on the surface—in the clouds, in the great lakes and rivers and oceans, the ice caps and aquifers. And most of the water on Earth does not exist in any of the three familiar states—ice, liquid, or vapor.
Water exists in a fourth form, one that is so exotic that despite its abundance and its importance, it almost never merits a mention outside of scientific circles. This vast reservoir of water—at least as much as in all Earth’s rivers and oceans and glaciers, perhaps four or six or ten Earth oceans’ worth—is locked in the rock deep in Earth’s mantle, in a layer about 410 kilometers (255 miles) below your feet. (All the water on Earth’s surface is referred to by scientists, for convenience, as “one Earth ocean.”)
Some of this exotic fourth state of water may be hiding in plain sight in the middle of your kitchen, if you have the green stone countertops made from the mineral serpentine. A kitchen island countertop of serpentine (say, 4 feet by 3.5 feet) could easily weigh two hundred pounds. Not just as solid as a rock—it is a rock. But of that two hundred pounds of serpentine, twenty-two pounds is H2O—ten liters of water fused into the stone. Not mixed in the way, say, you’d mix an egg into pancake batter. The water is baked into the very molecular structure of the stone itself, tucked in among the magnesium and silicon and oxygen that make up the lattice of the serpentine.
Much of the rock 410 kilometers deep in the Earth has some water squeezed into it in this way, but it’s not the familiar H2O. At that pressure and temperature—the weight of 255 miles of solid rock piled up, heated above 2,000°F—one of the hydrogens peels off the water, leaving the OH and the separate H to wriggle into the structure of the stone. Scientists call the resulting water-infused rocks hydrated minerals, or hydrous minerals (literally, “watery rocks”).
Here’s the thing that’s a little hard to grasp: Once you squirt that oxygen-hydrogen pair and that lone hydrogen into the crystal lattice of a rock, buried three hundred miles down, in what way are those atoms still water?
Steven Jacobsen, a geophysicist at Northwestern University, is a gracious host to this world of heat, pressure, and darkness that is almost completely inaccessible to humans. Jacobsen has used an enormous press (the kind you can make artificial diamonds with) to mimic the pressures and temperatures three hundred miles down and to squeeze water right into rock. He is devoting a large chunk of his career to studying the importance of wet rocks deep inside the Earth.
Q: So this idea that there is water inside these rocks—inside the structure of the minerals—is this a theory or a fact?
JACOBSEN: Oh, this isn’t a theory. It’s reality. Absolutely.
Q: And if the water is inside the molecular structure of the rocks, why do you scientists think of it as water? In what sense is it still water?
JACOBSEN: Well, it’s not water by any stretch of the imagination, of course. We use that term very colloquially.
Q: But it really is water, in fact?
JACOBSEN: Yes, it’s water, unquestionably. If you release the pressure and temperature, the hydrogen and the OH come out as water. If it’s not in the rock, it’s water. It is where most of the planet’s water might be, in fact. In the rocks.
The graphic-novel version goes something like this: In the right conditions of temperature and pressure, certain kinds of rocks literally suck water into their structure, much the way a sponge sucks up water. As the water goes into the rock, it dissociates—the H goes here, the OH goes there.
There is absolutely water in these rocks, and the scientists know it in at least three ways: These hydrated minerals are literally more pliant, more puttylike, than in their unhydrated state; the scientists can measure water’s pieces inside the structure of the rocks using infrared spectroscopy; and most important of all, when the pressure and temperature on the rocks are released in the right way, the H and the OH come squirting right back out of the rock, and they come out as water.
And here’s the thing: Scientists think they have figured out that these kinds of watery rocks are common in a band inside the Earth stretching from about 250 miles deep to about 400 miles deep, a layer 150 miles thick, a lot thicker than the film of water on Earth’s surface.
“Even if only 1 percent of that rock is water,” says Jacobsen, “that’s a lot of water, several times Earth’s oceans, in fact.”
Hundreds of scientists around the world are studying the physics of Earth’s deep water, and its impact. While water in this fourth state, this deep water, may be out of sight, while it may be harder to study and harder to understand than the water NASA discovered in 2009 on the Moon, Earth’s deep water is directly connected to the water crashing ashore at the Santa Monica Pier or the White Cliffs of Dover, the storm clouds crowding the horizon in Johannesburg or Shanghai.
EVERY SCHOOLKID IS FAMILIAR with the cheerful drawing illustrating the basics of the water cycle: Clouds drop rain or snow on the flanks of mountains; water runs off into streams and rivers and lakes, and then into the ocean, from which the beaming sun evaporates it (often in the form of lines that look like wiggling snakes rising straight into the air) to become clouds again. Precipitation, evaporation, precipitation.
The diagrams are always a little cartoony. The actual process itself is awesome, even majestic. The volumes of water that the Earth and the Sun are moving around are Olympian, so large they are measured in a unit rarely heard in the ordinary world: cubic kilometers. A single cubic kilometer, an imaginary cube one kilometer on a side, holds an incredible amount of water: 260 billion gallons, enough to cover the island of Manhattan to a depth of thirty-seven feet.
Every hour, on average, Earth’s oceans are evaporating 50 cubic kilometers of water into the air (13 trillion gallons). The entire United States uses only 410 billion gallons of water a day for all purposes—so every two minutes, the oceans create more clouds of fresh water than Americans use in twenty-four hours.7
Just the leaves from a single acre of trees might send eight thousand gallons of water up into the air in a day, enough to fill two-thirds of a typical backyard swimming pool.8
A molecule of water that evaporates into the air—from a fountain, from a puddle, from your skin—spends about nine days floating in the sky before returning to Earth as rain or snow.9 Half the Earth’s surface is typically covered by clouds, with the life of a particular cloud usually being no more than an hour.10
And how much water is floating up there in those fat black rain clouds, literally defying gravity until the rain falls? It is lakes full of water. If just an inch of rain falls on your half-acre yard, that’s 13,577 gallons of water— one inch, one storm, one small patch of ground.11
Perhaps the most mind-bending fact that shows up on the standard water distribution charts is something identified cryptically as “biological water.” It’s a small number, just 1,120 cubic kilometers—one-tenth the water cycling through the atmosphere at any moment, enough water to fill just one of the five Great Lakes (Erie).12
What is “biological water”?
It’s the amount of water ziplocked into the bodies of everything alive on the planet—earthworms, squids, pelicans, mosquitoes, pythons, giraffes, sardines, hippos, the swine flu virus, not to mention all the Earth’s trees, ferns, flowers, and grasses. And inside us too. That 1,120 cubic kilometers comes to 300 trillion gallons of water. Given that the average human—considering adults and children—contains about 5.5 gallons of water, people account for only about 38 billion of the 300 trillion gallons of “biological water.”13
Putting aside the question of how a scientist could calculate the total amount of water inside all the creatures in Earth’s biosphere, it’s a humbling number. Of all the water doing life-support duty, 99.9987 percent of it is inside creatures besides us.
One funny thing about the numbers describing how much water is streaming through the world—the total water volume for the Earth’s surface, the total frozen in glaciers, the total evaporating annually from land, the total inside crocodiles and poodles—is how precisely the numbers agree, no matter which source you consult. On the Web site of the U.S. Geological Survey, in grade school curriculum materials, in science textbooks, across the Internet, and even in a handmade table taped to the wall of a professor of natural resource sciences at the University of Adelaide in Australia—everywhere the numbers are exactly the same. It’s not just hard to believe the precision and lack of variance, it’s impossible. You can’t get complete agreement on a number as fixed as the diameter of the Earth, a measurement that doesn’t change as much as, say, the annual evaporation of water from the Indian Ocean. Almost none of the charts with the amazing numbers list sources—or they reference each other— but one indicates that the numbers are the work of a man named Igor Shiklomanov, from a chapter he wrote for a book edited by the American water expert Peter Gleick in 1993 called Water in Crisis.
And if you go to Gleick’s Water in Crisis, there on page 13 is exactly the same chart everyone else prints. Except this one is the original. Igor Shiklomanov, a highly regarded Soviet water scientist, prepared the chart based on his own analysis, and the work of Soviet colleagues, with some of the data originally published in 1974. Right in the text of his essay in Water in Crisis, above the chart, Shiklomanov writes with all modesty, “It should be noted that the data on the amount of water on earth (as the authors of the cited monograph themselves note) should not be considered very accurate; they are only approximations of the actual values.”
Given that very clear caution, it’s not just amazing how widespread the water data have become. What is so startling is that given the incredible leaps in computer modeling, water measurement technology from space, and computing power—not to mention the intensity and importance of climate change science and its dependence on moisture in the atmosphere—no one has come up with a fresh set of calculations. Shiklomanov’s seventeen-year-old chart, based on data almost four decades old, remains the standard.14
The real gap in the water cycle drawings, of course, is not the uniformity or precision of the numbers, but as Steven Jacobsen and his deep-water colleagues would point out, that most of the water is missing. It’s in the mantle, and it, too, cycles.
Joseph Smyth is a geologist at the University of Colorado, one of the pioneers in trying to understand the dynamics and significance of deep water (he was also Steven Jacobsen’s thesis adviser).
The water in the deep interior rocks of the Earth’s mantle gets there through the oceans. “The most significant way this happens is in the ocean crust,” says Smyth. Along the ocean floor is a mineral called olivine. As it happens, olivine reacts with seawater to create serpentine—the green stone that might show up as your kitchen counters. Then, at the places where the continents are grinding into each other, the ocean floor is “subducted,” it’s shoved downward into the Earth’s interior by continental drift. The water-saturated serpentine dives into the crust, taking its load of water with it.
You could release the water from your kitchen counters by heating them (it would ruin the counters, however). That, in fact, is exactly how the deep water comes back to the surface, says Smyth. “It returns mostly through volcanoes. When there’s an eruption in the Andes or at Mount St. Helens—that big eruption cloud is largely water, with ash mixed in.” A volcano’s eruption cloud is often 70 percent or more water. “What’s making the explosion, in fact, is water coming out of the magma,” says Smyth.
Exactly how much water has come to be stored in the mantle is a mystery—and one of the questions scientists are trying to answer.
“What’s going on there is extremely inaccessible,” says Steven Jacobsen. To say the least. The deepest hole humans have ever drilled is 12 kilometers (7.5 miles)—and that took the Soviets twenty-four years of effort and $100 million.15 As of 2008, the world’s deepest mine, that is, the deepest people can actually travel inside Earth, is just 3.9 kilometers (2.5 miles).16 Both of those are barely finger scratches on the surface of the Earth. The interesting action in deep water is at about 410 kilometers. So all the research is done using sound waves and seismology, and also huge, powerful presses that can mimic the pressures and temperatures 410 kilometers inside the Earth, allowing scientists to create samples of the kinds of rock found there, which they can then study. Re-creating those conditions requires so much effort that a hydraulic press two stories tall creates rock samples the size of the period at the end of this sentence.
Even if there are four or five earth-oceans of water deep in the Earth’s mantle, it’s not like finding a huge reservoir of oil or natural gas. Deep water isn’t something humans can sample even to study directly, let alone tap it to irrigate a dry patch of the Sahara.
But the water has at least three critically important roles.
First, Smyth, from Colorado, thinks that this fourth state of water, locked inside rock, may be how the Earth actually got its original supply of water.
“I think most of the water came here as hydroxyl (OH) in the primitive meteorites called chondrites,” says Smyth. “There isn’t universal agreement on this. And some of the water came as molecular water”—as cosmic juice, that is—“but I think most of the water came from these chondrite meteorites, with the water in them as hydroxyl.” (It would still have to have been formed in space first, of course.)
The water that has come to blanket the Earth would then have been released by the planet’s early volcanism.
It’s an intriguing theory, and one possibility among several. But the question of how Earth’s water got delivered is a messy scholarly splash fight at the moment, with several passionate camps. Distinguished research scientists will actually shout, referring to colleagues who disagree with them, “Well, has he read my latest paper on isotope distribution? Has he? You tell him to read that paper and he’ll understand how it happened!”
Second, there is little question that the “wet rocks” deep in Earth’s mantle are vital for plate tectonics—the water reduces the viscosity of the rocks, and their resulting “plastic” quality enables the continents to slide beneath and over each other. Those sliding plates create the geology of much of Earth.
Finally, and perhaps most important, the deep water may be the only reason Earth is a blue planet at all.
“We’ve had relatively constant ocean volumes over time, going back at least 500 million years,” says Jacobsen. “Sea level does rise and fall, yes, but on the scale of dozens of meters.” Geologists call the part of the continents that crowns above the oceans “continental freeboard.” If you don’t fret too much about the edges of the continents (which, unfortunately, are where most of the people live), the amount of continental freeboard is remarkably stable going back hundreds of millions of years.
Considering that there might easily be five earth-oceans of water stored in the planet’s interior, that sea-level stability is intriguing. Even the release of a single earth-ocean—doubling the surface water on the planet—would swamp everything.
“Maybe the water in the mantle is why we have those oceans,” says Jacobsen. “We can’t extract and drink that water, but maybe the water in the mantle is buffering the amount of water in the oceans.”
The mechanism isn’t understood. But the importance is.
Jacobsen’s mentor, Smyth, goes back to Earth’s beginnings. “Early in Earth history, when it had these big violent impacts from meteors and comets, the atmosphere got blown off a few times during the first 100 million or so,” Smyth says. “It may be that Earth has retained water through the last 4.3 billion years by having this reservoir of water in the interior.
“If the water were just on the surface, there might not be any water on Earth now.”
PERCY SPENCER, an executive with Raytheon Manufacturing, was a self-educated orphan whose formal schooling ended at age twelve. An intuitive and brilliant engineer—Spencer ended up with 130 patents—he worked alongside MIT’s physicists developing technology for World War II, and his practical sensibility helped figure out how to mass-produce magnetrons, the electronic guts of the radar units whose widespread use helped win the war.17 As the war was wrapping up in 1945, Spencer was touring Raytheon’s lab in Waltham, Massachusetts, where magnetrons were being tested. He noticed that the Mr. Peanut candy bar he routinely carried in his shirt pocket to feed the squirrels was melting.
It was the kind of moment for which Spencer was famous—he knew that high-frequency radiation from the magnetrons had melted the candy bar. But rather than pass it off as a messy inconvenience, he was intrigued at the possibilities.
As the story is told, Spencer immediately dispatched a Raytheon office boy to buy a package of unpopped corn kernels. He put the unpopped corn in range of the magnetron, and in a satisfying moment familiar to every hungry office worker, the popcorn popped all over the lab.
Percy Spencer had discovered both the microwave oven and its single most distinctive cuisine in a single moment.18 Today, the working heart of a $39 microwave from Wal-Mart—the magnetron, which generates the microwaves—is the same as the technology that helped the Allies use the then-new radar to defeat Nazi planes and U-boats.
Percy Spencer and Raytheon went on to patent the new cooking technology, but it took them decades to figure out how to deliver the convenience of the microwave to the kitchen counter, and Raytheon had to purchase appliance maker Amana to finally make it a success. The first Amana microwaves honored the technology’s roots—they were called “Radarranges,” a brand Amana still uses, now with just a single “r” in the middle. Today, 96.4 percent of U.S. homes have a microwave oven—more homes than have a landline telephone or a computer—and a typical family of four goes through the equivalent of forty regular-size bags of microwave popcorn a year.19
When you use a microwave oven, to reheat coffee or puff a bag of popcorn, you’re really cooking with water—specifically with water molecules.
The microwave oven only cooks because of microwaves’ affinity for water at the molecular level. Microwave radiation—the same kind of radiation as radio waves or light waves—moves at a frequency that water molecules absorb. When you microwave a baked potato or a cardboard tray of frozen macaroni and cheese, it is the water molecules that get energized, and that do the cooking.
In fact, each individual water molecule is really a tiny magnet—the three joined atoms look a bit like Mickey Mouse’s head, two hydrogens as the big ears, one oxygen as the head. The hydrogen “ears” create a positive side, the single larger oxygen is the negative side. When microwaves come zinging through, each water molecule tries to orient itself in the waves of radiation, and ends up spinning. Water molecules inside a cup of coffee, or a baking potato, can spin 1 billion times a second in response to the microwaves.
The water molecules’ motion creates heat, which cooks the surrounding food. Microwave popcorn pops when the 14 percent of each kernel that is water vaporizes into steam, and expands to pop the kernel’s hull loose. (Conveniently, most plastics, dishes, and things like paper plates are transparent to microwave radiation, and a paper plate doesn’t contain many water molecules.)
Despite its sturdy simplicity, in fact, water is a complicated, unusual, almost enchanted substance—not in the emotional or cultural sense, but literally, physically, starting right at the molecular level, with the very magnetic quality that allows Percy Spencer’s “radar range” to work.
Scientists refer to molecules that are tiny magnets—one end with a small positive charge, one with a small negative charge—as polar molecules. In the case of water, the polarity has much more significance than making microwave popcorn possible.
The polarity creates a stickiness among the water molecules, like the clinginess of socks in the clothes dryer.20 The stickiness of liquid water molecules is called hydrogen bonding. Those hydrogen atoms—the ears on the mouse head—are bonded tightly to the oxygen atom in their own water molecule. But because of their slight positive charge, they are also attracted to the slightly negative charge of the oxygen atoms in the water molecules floating nearby. Like the socks in the dryer, the fabric in each sock is a unit knitted together, but the socks also have a clinginess for neighboring socks.
The hydrogen bonding isn’t something theoretical or ephemeral. Hydrogen bonding is as basic to the character of water as its sparkle, its splash, its very wetness. That clinginess of water molecules for each other is, in fact, the glue that holds much of the natural world as we know it together.
Scientists have been able to measure that liquid water molecules are up to 15 percent closer to each other because of hydrogen bonding than they would be without it. And the stickiness of the molecules for each other gives water a whole range of surprising qualities, which we have come to depend on.
Because of the extra stickiness from hydrogen bonding, water’s reaction to changes in temperature is quite unusual. Water is a liquid through an incredibly wide range of temperature—it is liquid for 180°F, from 32° to 212°—and it is liquid over a range of temperature hospitable to life. Much of the chemistry and biology that we rely on takes place in liquid water—life requires not just water, but liquid water. As it happens, water is a liquid at what we think of as room temperature.
Hydrogen sulfide, a substance much like water chemically (H2S instead of H2O), is a gas at room temperature. If water were a gas at room temperature, there likely wouldn’t be any rooms, because there would be no creatures to make them.
The stickiness allows water to absorb and hold heat well—it is a good insulator, which allows living things to use it to regulate their own temperatures more easily. It also means the vast liquid ocean film that covers 71 percent of Earth’s surface tempers the globe’s climate—ocean temperatures vary just one-third as much as land temperatures.
And almost everyone knows the most familiar anomaly of water: Solid water is less dense than liquid water.
Ice floats.
Every basic lesson in physical chemistry would tell us that ice should sink in a glass of water (and that icebergs should sink to the bottom of the ocean). In liquids, the molecules are packed tighter than in a gas; in solids, the molecules are packed tighter still.
But in the case of ice, the hydrogen bonds do the opposite of what they do in liquid water. As water freezes, the tiny water-molecule magnets want to put some space between each other as they lock into place. The hydrogen bonding enforces a distance that causes ice to form a crystal lattice that is 9 percent less dense than the same amount of liquid water.
The result is that ice cubes in a tray grow 9 percent as they freeze. And ice floats. If ice didn’t float, rivers, lakes, and even the oceans would freeze—the ice piling up from the bottom in winter, never melting fully in summer—and most aquatic life would die. As it is, the ice layer across the top of lakes and rivers does just the opposite—it acts as a layer of insulation, keeping the rest of the water warmer than it would otherwise be, keeping it liquid, and allowing aquatic life to survive each winter.
Water’s stickiness as a liquid, its lower density as ice, and all the things those qualities make possible—those are the kinds of qualities that cause even scientists who study water to go a little mystical on you. It makes perfect molecular sense—if you’re a chemist or a physicist—that water lightens a bit when it freezes. And yet nothing else in the regular world does that, and it is precisely that quality of water that enables life to go on living.
Liquid water exists at ambient temperature because of its somewhat quirky molecular structure. Liquid water just happens to be the perfect medium for the raw materials of life to get together, to find each other, and every bit of life depends on liquid water to be alive. And then, when water freezes, it does so in a surprising way that, almost miraculously, happens to provide protection for the very life that water itself makes possible.
Water is a great solvent—almost anything will dissolve in water, in part because of its polar molecules. All the chemistry of our bodies—the conversion of food to energy, the conversion of energy to a ballerina’s pirouette or an opera singer’s aria—all that chemistry takes place in the hospitable environment of tiny drops of water inside cells that allow all kinds of molecules to move freely back and forth doing the work keeping us alive requires. (The solvent qualities also mean water is easy to pollute, and that water is a great harbor of all kinds of things that make people sick, from germs to heavy metals.)
For the record, water molecules are conveniently tiny—the interior of a single human red blood cell, pretty small on the scale of cells inside our body—that one red blood cell is the equivalent of a vast domed football arena, with a single H2O molecule being about the size of a children’s party balloon. One blood cell can hold 3 trillion water molecules.21
The physics and chemistry of water—which amount to the alchemy of life—generally get short shrift, in high school, in college, in daily life. Few of us know enough to appreciate that the ice cubes floating in the glass of iced tea are like some kind of cosmic magic trick, let alone know enough to marvel that the whole sentient universe hangs on that trick.
Water really is the genesis ingredient for life at all levels—water is so fundamental to everything involved in creating, reproducing, and sustaining life that it’s possible to imagine that God created water, and let water do the work to create life.
WATER HAS A SECRET LIFE that goes beyond its birth in deep space one molecule at a time, its quiet accumulation by the oceanful in the deep rock of Earth, and its role in bringing each bag of microwave popcorn to life. Water is so adaptable, so nimble, that as we humans have gotten more inventive and more demanding, water has come right along with us, becoming as crucial a tool in the digital era as it is to a farmer.
Every modern electronic device—from the simplest desktop calculator, to our iPhones and the computers that control our car engines, our medical diagnostic machines, and the servers that run the Internet—relies for its creation on water, but a kind of water so exotic that it exists nowhere on Earth, except inside microchip factories.
In Burlington, Vermont, at one of only two IBM semiconductor factories in the world, IBM turns ordinary water into a liquid so alien that it’s not safe to drink, and it accomplishes that by doing nothing more to the water than cleaning it.
IBM creates huge quantities of this purified water—2 million gallons a day, 80,000 gallons an hour, without stopping, because you can’t make microchips without water, and for the microchip water to do its job, it has to be water of absolute purity.
The IBM chip plant in Vermont—in Essex Junction, just northeast of Burlington—has eighty acres of floor space, and with a staff of five thousand, is the largest employer in Vermont. The buildings are two and three stories of brown brick, with narrow smoked-glass windows that make the place look like a down-at-the-heels community college from the 1970s.
Inside, however, is one of those space-age facilities that make the modern world possible. IBM Burlington produces semiconductors that give intelligence to printers and cell phones, TVs and GPS handhelds and cameras. Everyone has an impressionistic sense of what computer chips look like—sometimes you get a glimpse of them when you change the battery on your TV remote control or when you drop your cell phone and it cracks open. Silvery lines and dots on a green plastic board.
But the actual features on the chips themselves—the pathways that the electrons follow to deliver our text messages or flip the flat-screen TV between HBO and ESPN—those pathways aren’t something you’ve ever seen. They are just 90 nanometers wide. They are so thin, not only can’t you see them with the naked eye, you can’t see them with a microscope. The pathways can’t be seen with visible light, because the narrowest visible light waves are 400 nanometers—light skates right past something 90 nanometers wide without noticing. You have to use a scanning electron microscope to see the pathways.
And yet the pathways that can’t be seen are designed with the utmost architectural precision, and they must be laid down with the same precision, or 2 + 2 will not, in fact, routinely equal 4. The round semiconductor wafers that IBM Burlington’s technicians are making often require as many as seven hundred steps to manufacture, over days or weeks. Between the steps, the chemical solutions used to etch patterns and lay down layers of circuits have to be washed away.
With water.
But the water itself is a problem, because water coming from the tap—clean enough to drink, and quite refreshing in Vermont—is just filthy from the perspective of a computer chip. Precisely because of water’s invaluable solvent properties, the water coming into IBM Burlington is awash in chunky debris of every kind—minerals, ions, bacteria, viruses, and just plain old bits of dirt way too small to bother a person but boulder-size to a computer chip. You’d no more wash your computer chips in tap water than you’d ladle water from your toilet to make lemonade.
Water is, in fact, the thing those chips need to be washed with. It is the only thing they can be washed with, but it literally has to be nothing but water. Nothing but water molecules.
Here’s how sensitive a silicon wafer with 90-nanometer pathways is. Imagine that the tiny pathway is, in fact, the width of a sidewalk. In that case, if a human hair were lying across it, you’d be in trouble, because the hair would be three-quarters of a mile in diameter. You’d have to climb it like a three-thousand-foot mountain to get to the sidewalk on the other side. If you were walking along your 90-nanometer sidewalk and happened to encounter a single red blood cell—just one—you wouldn’t miss it. That single cell would be as long as a football field—you’d have to detour fifty yards to the right and then back to resume walking on the sidewalk. Even if, while walking on your 90-nanometer sidewalk, you encountered something really small, a single particle of influenza virus, even that would force you off the path. A particle of flu virus would be a spherical blob four feet across.
Indeed, if you were to stumble on a single water molecule on your walk, you might well notice it: A water molecule would be about the size of a single, green M&M’s candy.22
Making microchips is a demanding, complicated, unforgiving business, a profession all its own, and the clean water is essential, but hardly the hard part. Making the water for the microchips is also a demanding, complicated, unforgiving business—it requires a factory all its own, in fact.
Deep inside IBM Burlington is a big industrial area known as the Central Utilities Plant (CUP). In a sprawling space dense with pipes, pumps, and equipment, regular tap water that starts in Lake Champlain is turned into what the semiconductor industry calls ultra-pure water (UPW).
“Ultra-pure water is 10 million times cleaner than regular tap water,” says Lindsey Stahl, who is an ultra-pure water engineer at IBM Burlington. It’s hard to know what “10 million times cleaner” means, exactly. Stahl’s boss is a veteran IBMer named Janette Bombardier, who is director of site operations at IBM Burlington, everything from cleaning the bathrooms to cleaning the microchip water.
“UPW means taking every trace element and every ion out of that water,” says Bombardier, “so there is literally nothing in it but the water.”
This isn’t like taking your tap water and pouring it into the Brita pitcher. The basic process to make UPW involves eighteen steps. The sixth of those steps is reverse osmosis (RO)—the high-intensity, high-energy process that the everyday world views as “taking everything out” of water. Huge reverse-osmosis plants in Israel and Florida and Australia turn seawater into city-size volumes of drinking water. Coke and Pepsi are routinely mocked for taking perfectly clean municipal water and putting it through RO plants in order to “make” their branded bottled waters—Coke’s Dasani and Pepsi’s Aquafina. RO is so effective at cleaning water that Coke actually adds back a frisson of minerals to give Dasani what the company calls “a pure, crisp, fresh taste.” Unpolished RO water—that is, RO water with nothing added back—is so clean that it feels flat on the tongue.
For ultra-pure water, though, a river of RO water is the basic raw material. RO cleans the water to the point that IBM Burlington’s UPW factory can really get down to business.
There are a dozen cleaning steps after the reverse-osmosis process— huge, specialized filter beds to take out ions; tubes filled with UV light to blast apart any organics. The final step—the eighteenth—is a filter with pores that are 20 nanometers. Those holes are smaller than anything but individual molecules and parts of cells—although still seventy times bigger than a water molecule.
Water is a good cleaner precisely because “cleaning” is another way of saying “dissolving”—water dissolves stuff and carries it away. Water’s supersolvent qualities are what make it so hard to clean, in fact—while you’re taking stuff out, water is looking around for anything it can enfold and carry away.
That’s one of the things that make ultra-pure water in particular great for microchip manufacturing. “UPW is hungry,” says IBM’s Steve Blair. “It’s a really good cleaning agent. It will take anything it can get.”
Cleaning the water makes it a much better cleaner.
The electron-carrying pathways on microchips have gotten smaller and smaller over the last twenty years—that’s why our electronic devices have been able to get smaller while doing more. As the pathways have gotten smaller, the water used to make them has had to get cleaner.
“Every year, the purity requirements are increased,” says Lindsey Stahl, the IBM water engineer. “What we called UPW ten years ago would be laughed at today. But we’re at our limit of the cleanest we can do. It’s almost as clean as you can make it.”
Ultra-pure water is found nowhere on Earth because water out in the world is constantly flowing past, over, and through things, from which it is absorbing particles. While every microchip plant uses UPW, water so clean is a purely human idea, and a purely human creation.
Which raises an irresistible question: What does ultra-pure water taste like?
Janette Bombardier, the site operations manager, is an engineer who has worked for IBM in Vermont for thirty years, including six years in charge of water operations. She’s friendly, with more the demeanor of a middle-school music teacher than a high-powered high-tech executive.
Her staff makes 83,000 gallons of ultra-pure water an hour, the cleanest water on Earth. So what’s it taste like? Has she ever opened a spigot and drawn herself a glass?
There is the longest pause in the conversation.
“I have never had a glass,” she says. “I have no idea what it tastes like.” She pauses again. “It has never occurred to me to taste it.”
In fact, in many factories that use UPW, it’s not just regarded as an industrial solvent, but it is considered akin to a poison. A swallow or a glass of it won’t hurt you, but as it does with the microchips, UPW is “hungry”—it will leach minerals right out of your body tissues.
Eric Berliner, an environmental manager for Bombardier, pipes right up. “I’ve tasted it,” he says. “It was horrid. I stuck my tongue in it. It’s very bitter. Horrible.”
Even when it comes to water, clean isn’t everything.
WATER HAS A REMARKABLE RANGE OF QUALITIES—it can be playful or comforting, it can be annoying, it can be powerful or erotic. But in terms of water’s fundamental character, its personality, water is elegant, it’s smart, it’s a little sly in terms of what it can pull off when you’re not looking (the Grand Canyon, for instance). But water is dependable. Water doesn’t let you down; it rarely disappoints.
In 2008, the folks at PUR water filters went looking for a voice to bring water to life, and after sifting through hundreds of candidates, they chose Zach Braff, the actor who plays the recovering-nerd doctor J.D. on the TV series Scrubs.
Okay. He does a reasonable job. But Zach Braff’s a little … goofy for water. Water doesn’t often descend to the Old Testament baritone of James Earl Jones. But water isn’t really ever goofy—even coming out of a pink squirt gun, or splattering from a water balloon, water isn’t goofy.
Water is more Paul Newman or George Clooney, Faye Dunaway or Annette Bening—not urgently in need of drawing attention to itself, but perfectly capable of holding center stage. Water is a grown-up, quietly forceful, not self-important, with both a playful twinkle and a graceful wink, as the occasion requires.
Water is charming.
Part of water’s charm is the way it combines simplicity and complexity, in both its physical nature and its qualities. Water is just three atoms—one oxygen, a pair of hydrogens—but with those three atoms, it is the elixir of life in all its variety and beauty. A single molecule of DNA, by comparison, has 204 billion atoms.23
Water’s stickiness—its socks-in-the-dryer quality—is a result of its slight polarity, one side a little positive, one side a little negative. But that simple stickiness unfurls a set of complicated properties—the ability to absorb heat, the willingness to dissolve almost anything, the fact that ice floats—that make water the force that shapes the world.
Water’s personality, in fact, is layered with polarity, both inherently and in the ways we approach and manage water.
Water is transparent, and also reflects light.
Water is soft and soothing, and also hard as concrete.
Water is comforting, and also threatening; gentle, and fierce.
Water is the source of life, and also often a source of death.
Water is all-important, indispensable, but almost always free, or essentially free.
Water is the most basic necessity to human life, and also a symbol of luxury and indulgence.
Water is sexy and alluring, and also often appalling and repugnant.
Water is as natural and wild as anything in the world—from white-water rapids and waterfalls to the power of hurricanes—and yet water is thoroughly domesticated in everyday life.
Water is a team player—a partner in a cosmic gallery of natural events—and yet water has an independence of both body and spirit. It participates in all kinds of processes but emerges again as simply water.
Water is as familiar as anything in ordinary life, and yet largely ignored, misunderstood, overlooked.
We often keep the two kinds of water separate in our brains and in our day-to-day stewardship—utility water and beautiful water, water’s immediate functional role, and water’s larger context. That, in part, is why we’re drifting into trouble, failing to get water to people who don’t yet have it, and doing an indifferent job of managing water in places that take abundant water for granted.
Our relationship to water goes way beyond what we know about it. The facts about water, the science, the chemistry, the geology—those are both fascinating and important. There would be no advanced civilization today without that understanding—we would have long since poisoned ourselves.
But our relationship to water is at least as much emotional as it is analytical. That’s why a bottle of Evian tastes so good that we pay a thousand times more for it than for the same amount of water from the kitchen faucet. It’s the reason that water pipes hidden beneath our streets are poorly maintained, it’s why people around the world get so angry when their water bills go up.
We need to understand that the science of water goes only so far in explaining how we deal with water every day, both as individuals and as a society. And our feelings about water are often so powerful, so visceral, that we need to be sure they don’t prevent us from seeing water clearly.