Cold (27 page)

What good can come from a couple of thousand molecules of rubidium at 460 degrees below zero? Of what use is a Bose-Einstein
condensate?

For one thing, very cold temperatures win Nobel Prizes. Onnes got one in 1913. The discoverer of a method of cooling called
adiabatic demagnetization got one in 1949. The trio of physicists who developed laser-based cooling methods got one in 1997.
And Eric Cornell and Carl Wieman received one in 2001 for their work with rubidium atoms near absolute zero. At a press conference,
Cornell was asked how it felt. “Pretty good,” he said.

Drebbel’s air-conditioning of Westminster Abbey came to nothing. To the extent that he is remembered at all, it is for a submarine
that he plied along the Thames River. He died poor. William Cullen’s first refrigerator in 1748 was little more than a footnote.
Cullen himself did not see any commercial value in refrigeration. John Gorrie, working on both refrigeration and air-conditioning,
and actually using it to cool both his home and a hospital ward, died in 1855 before he could attract investors. Potential
investors, it is said, believed that it would be cheaper to ship ice south than to make it in Florida. Another ice plant went
belly-up when its owner made the mistake of building it in Minnesota. But in 1859, Ferdinand Carré sold a cooling machine
to a Marseille brewery. By 1889, cold air was being piped from central cooling plants to customers in New York, Boston, Los
Angeles, Kansas City, and St. Louis. And by 1902, the New York Stock Exchange was air-conditioned.

By 1880, refrigeration was cheaper than natural ice. With efficient refrigeration, food could be shipped to markets. Hog production
grew. Over a few years, beef exports from the United States to the British Isles grew from a hundred thousand pounds a year
to seventy-two million pounds a year. More than a hundred thousand refrigerated railroad cars appeared almost overnight. Suddenly,
midwestern farmers could undercut New England farmers on dairy products. Refrigeration increased the profitability of ranching,
and ranches expanded, implicating refrigeration in the last phase of the eviction of Native Americans from their ancestral
lands and the near extinction of the buffalo. Clarence Birdseye, inspired by the quality of fish frozen at forty below after
ice fishing, developed techniques for flash freezing food in 1923. By 1928, Americans were buying a million pounds of flash-frozen
food a year. With air-conditioning, people could live comfortably in Florida and Arizona and New Mexico. By virtue of the
air conditioner, skyscrapers grew taller, into the range of gusting winds that prevented the opening of windows.

At colder temperatures — the temperatures of Onnes and Dewar, the temperatures of liquid nitrogen and liquid oxygen — steel
manufacturing was improved. By 1914, Robert Goddard was using liquefied gases as rocket fuel. The Mercury rockets, the Gemini
rockets, the Apollo rockets, and the space shuttle have all used liquefied gases for fuel. The tip of a probe threaded up
a patient’s femoral artery to the heart and chilled to a hundred below can treat cardiac arrhythmias. At 180 degrees below
zero, old tires shatter, allowing their material to be recycled. Two hundred and fifty pounds of superconductors at the temperature
of liquid nitrogen can replace eighteen thousand pounds of copper wire. Cryosurgery, cryogenic tire recycling, the liquiefication
of natural gas, and the manufacture of sophisticated electronic equipment require temperatures that could not be reached if
not for the obsessions of Onnes and Dewar and their colleagues and competitors, all of whom, at one time or another, were
likely asked about the usefulness of their explorations of Frigor.

In 1997, researchers came up with a way of dripping single, very cold atoms from a microspout. In 1999, it became possible
to fire streams of atoms in any direction, a kind of atomic laser. Also in 1999, a Harvard University team shined light through
a Bose-Einstein condensate, slowing the beam to just thirty-eight miles per hour. In 2001, a beam of light was, for a moment,
stopped entirely, and by 2007 the team could slow light down, stop it, and restart it. The team leader, Lene Vestergaard Hau,
told reporters, “It’s like a little magic trick.” The secret behind the magic: a tiny lump of Bose-Einstein condensate.

Useless stuff, all of it, surely no better than the cooling of Westminster Abbey or Dewar’s 1899 lecture-hall tricks with
liquid hydrogen.

I
t is March fifth and five degrees below zero in Anchorage. Throughout the day, I have been indoors and warm, taking a winter
survival course with a crew of biologists headed north to look for polar bear dens. At their research site, on the edge of
the Beaufort Sea, the temperature hovers around forty-seven below zero, not counting windchill.

The instructor shows us his parka, insulated with a hollow synthetic fiber. He shows us how the hood sticks out past his face,
forming a snorkel that tunnels heat. “Twenty-five percent of radiant heat loss,” he says, “is from your head.”

But you are leaking heat everywhere. You sweat, and every molecule that changes from liquid to vapor takes away heat. You
sit on the ground, and heat is conducted from your rump to the snow. You stand, and air moves past your body, even on a still
day, the convection currents bringing in cold and taking away heat. You breathe, sucking in cold air and exhaling warmth.
You are a human radiator giving up the heat you need to stay alive.

The instructor talks about hypothermia. “You’re not dead until you’re warm and dead,” he says. He shows a frostbite video:
lifeless fingers blackened to the knuckles.

He talks about the importance of a trip plan. “Know where you are going,” he says, “and make sure someone knows when you will
be back.”

“Do you have things on your person that will help you survive?” he asks.

“Cotton kills,” he says, discouraging us from jeans and cheap T-shirts. He urges us toward certain synthetic fibers.

He talks about hypothermia warning signs, which he calls “the umbles.” You mumble as your jaw muscles chill. You fumble as
your fingers stiffen. You grumble complaints as your core temperature drops. You stumble drunkenly as your central nervous
system slows. You tumble. You are down in the snow. Without help, you will die.

“You’re not dead,” someone quips, “until you’re warm and dead.”

After the class, I make the mistake of handling my skis and poles with bare hands. Chilled metal of ski edges and poles sucks
away heat. I pull on light synthetic mittens. They are ten years old, and the palms are worn thin. An index finger, numb,
shows through a hole. Some sort of white stuffing, a petroleum product of some kind, pokes out at a seam. I ski hard under
birch trees in the flat evening light, but ten minutes later both hands are numb. I rip open two chemical heat packs, one
for each glove. They are all I have on my person. Each pack is two inches on a side, a thin white mesh holding a black powder,
nothing more than iron, salt, some wood fiber, and activated charcoal. Exposed to air, a chemical reaction moves forward,
and the pack releases heat. Their quality varies. At five below, with holes in my mittens, it is hard to tell if they are
even working.

My dog runs into the forest and reappears a moment later, the frozen carcass of a snowshoe hare clutched in his jaws. With
his trophy he trots along behind me, without a trip plan, with no understanding of frostbite, which affects dogs just as it
affects people, with nothing but the rabbit on his person to help him survive, wearing neither synthetic fibers nor cotton,
tail arched upward, ears erect, head up. If dogs can smile, he is smiling now.

Angora rabbits, highly bred for long soft fur, look more like puffballs than rabbits. They were first raised in the Carpathian
Mountains near Poland when the local people realized that rabbit fur provided a softer alternative to sheep’s wool. This occurred
around the sixth century, about the same time the spinning wheel appeared in India and several hundred years before cotton
socks showed up in Egypt. The word “angora” was used in the language of these people and is sometimes said to mean “not sharp.”

Sheep’s wool feels coarser than angora, scratchier, but also warmer. Sheep, too, are easier to care for than rabbits and far
easier to herd. Wool was being spun into yarn and used in clothes for at least four thousand years before anyone tried the
same trick with rabbit fur. Today there are more than forty breeds of sheep producing two hundred varieties of yarn. There
are the soft wools, merino and rambouillet and debouillet. There are the medium wools, such as that of the Finnsheep, said
to be good for gloves and sweaters and jackets. There is the coarse wool of the Scottish Blackface and the Welsh Mountain
sheep, the latter said to be good for rugs.

Wool is judged by the diameter and length of its individual hairs, as well as by color and curl. The cream of the wool crop
comes from the sides and shoulders of the sheep. After shearing and sorting, grit and dirt are washed from the wool, and then
it is passed through rollers with wire teeth in a process called carding. Carding untangles the fibers and arranges them into
a flat sheet called a web. From there, the wool becomes yarn of various diameters, and the yarn becomes sweaters or pants
or shirts or rugs, all with a quality that is distinctly absent from cotton. Wool, when wet, stays reasonably warm, losing
only a fraction of its insulative character, but cotton, when wet, conducts heat nine times more efficiently than it does
when dry. Take a pair of cotton jeans, throw them in a mountain stream or a pond or a bathtub full of water, and take them
out. They are heavy with water. Cotton kills because the fibers hold water. They will suck the heat right out of the unfortunate
victim foolish enough to wear them in the cold. For survival in the cold, naked skin may be better than wet cotton jeans.
Take a pair of wool pants, throw them in water, pull them out, and they are not so heavy. Wool, under a microscope, is oval
in cross section. It curls as it grows and is naturally springlike. Each hair is covered with scales and coated with a waxy
outer layer of lanolin that repels water. Air spaces reside between the curls, even in wet wool, and it is these air spaces
that insulate the wearer.

The key to warmth is to make sure that air does not flow. The key is to trap air in small spaces, in the spaces between the
curls of wool fibers or between layers of clothing.

Toward the end of World War II, before the Americans dropped two atomic bombs on Japan, preparations were under way for what
promised to be a very ugly amphibious invasion. The U.S. Army’s Wet-Cold Clothing Team was deployed to Kwajalein, Saipan,
Tinian, Guam, and Iwo Jima to teach the principles of layering to men accustomed to fighting in tropical jungles. In a jungle
clearing or just before a USO show or in a mess tent, the Wet-Cold Clothing Team demonstrated the use of wool clothes. “Keep
it clean,” they would tell the men. “Keep it dry and wear it loose.” They described heavy losses from hypothermia and frostbite
in the war in Europe. They described the permanently crippling effects of frozen fingers, toes, and feet. Under the tropical
sun, the instructors explained that staying warm depended on the trapped air between layers that were individually reasonably
light. Part of the trick was to wear what you needed and carry the rest, thereby avoiding sweating. Put on a layer when you
are cold, and take off a layer when you are warm. The instructors would put on a layer of wool, explain its purpose, add another
layer, explain its purpose, add another layer, explain its purpose, and so on, until they were fully layered for cold-weather
soldiering. The training likely helped thousands of soldiers who had never before been confronted by cold. The heavier instructors
lost twenty pounds donning woolen layers in the tropical heat.