Read Why Do Pirates Love Parrots? Online
Authors: David Feldman
Why Do Pirates Love Parrots? (23 page)
W
e knew that the Earth’s core is hot, but not how hot. Actually, even geologists don’t know exactly what the temperature is, either, but they know it is almost as hot as the Sun. That’s hot.
Luckily for us, the surface of the Earth is considerably cooler. After all, the surface is losing heat by being in contact with cooler air. But the core is continually heated by the decay of radioactive elements. Scientists believe that the original heat from the formation of the Earth is still being played out in these transformations. The Sun is likely to expand and burn us before the core of our planet cools off.
The rule of thumb has traditionally been that for every sixty feet in depth, the temperature of the Earth increases by one degree Fahrenheit. But this old approximation was based on distances that scientists could measure by drillholes. If this ratio held true all the way to the core of the Earth, its temperature would be 180,000 degrees Fahrenheit. Most geologists agree that the actual temperature is closer to a still unfrosty 9,000 degrees Fahrenheit.
Why are we more worried about future global warming when our own core is so incendiary? The amount of heat that reaches the Earth’s surface is not enough to affect it drastically, and what heat there is quickly radiates to outer space. In their book,
Physical Geology,
Brian J. Skinner and Stephen C. Porter emphasize that the heat transfer is not uniform:
The heat loss is not constant everywhere. Just as the geothermal gradient varies from place to place, so does the heat flow, which is greatest near young volcanoes and active hot springs, and least where the crust is oldest and least active.
Of course, the Earth’s crust helps insulate the core from losing more heat. These cracks in the crust, like volcanoes and springs, are the few venues that allow us to glimpse the heat trapped in the sizzling core below.
Over the past few years, scientists have developed the ability to measure radioactivity more precisely through measuring particles called “antineutrinos.” Scientists have long suspected that radioactivity might be responsible for all the heat generated at the Earth’s core, and geologists are optimistic that eventually they will be able to map exactly where the energy is being generated. Even more recently, two University of California, Berkeley, scientists discovered that potassium can form an alloy with the iron in the Earth’s core. Although Dr. Kanani Lee found that potassium might comprise only one-tenth of one percent of the Earth’s core, “it can be enough to provide one-fifth of the heat given off by the Earth.”
The University of California, Berkeley announcement of the potassium discovery presents the current consensus:
The Earth is thought to have formed from the collision of many rocky asteroids, perhaps hundreds of kilometers in diameter, in the early solar system. As the proto-Earth gradually bulked up, continuing asteroid collisions and gravitational collapse kept the planet molten. Heavier elements—in particular iron—would have sunk to the core in 10 to 100 million years’ time, carrying with it other elements that bind to iron.
Gradually however, the Earth would have cooled off and become a dead rocky globe with a cold iron ball at the core if not for the continued release of heat by the decay of radioactive elements like potassium-40, uranium-238 and thorium-232, which have half-lives of 1.25 billion, 4 billion, and 14 billion years, respectively. About one in every thousand potassium atoms is radioactive.
As you have seen, scientists tend to take the long view. Although San Francisco biophysicist Joe Doyle later reiterated the “radioactive theory,” his first response to why the center of the Earth is still hot was:
There hasn’t been enough time for it to cool yet.
Submitted by Lance Burpee of Lisbon Falls, Maine. Thanks also to Peter Gosling of Ann Arbor, Michigan; and Charles Scourfield of Moss Vale, New South Wales, Australia.
“Laugh and the world laughs with you. Snore and you snore alone.”
N
o doubt about it. The delicate issue of snoring has caused fussin’ and feudin’ in more than a few relationships. Abigail “Dear Abby” Van Buren published a letter from “Frantic in Fresno,” a woman who was married for fifteen years to a man whose snoring woke her up “wondering who was mowing the lawn,” and who complained about having nightmares in which “a tugboat was stuck in the bedroom.” The husband wouldn’t allow Frantic to sleep in another bedroom, and wouldn’t seek medical help for his condition, which, come to think of it, didn’t keep
him
up nights.
Abby asked her readers for their comments, and received more than 5,000 replies. More than 90 percent of the respondents reported that they slept apart from their snoring mates. Abby concluded that “love is blind, but not deaf,” adding that when women were confronted about snoring, they took it as an insult. In fact, their mates reported that most women wouldn’t admit to snoring.
It’s hard not to joke about snoring, but consider this: The loudest snore ever measured, 92 decibels, exceeds the United States’ Workman’s Compensation threshold for requiring ear protection on a worksite (90 decibels). By comparison, normal speech is approximately 40 decibels; normal city traffic, 65 decibels; a jet plane, 110 decibels; a jackhammer, 120 decibels; and the pain threshold (think of a heavy-metal rock concert), 140 decibels.
About one-half of adults snore occasionally, and about one-quarter regularly. The two most popular stereotypes about snoring happen to be true: Older folks, as we reported in
Do Elephants Jump?
, snore more than younger ones; and more men
do
snore than women. Almost twice as many men as women snore, but women start catching up as they pass middle age. About 55 percent of men over 60 snore, compared to 45 percent of women over 60.
What causes snoring? Bad vibrations. When we sleep, our respiration rate lowers, but we continue breathing. With luck, the air passageways between the nose and throat and our lungs remain clear while we are asleep. If so, we hear at most a few “zzzzzz’s.” But if there is an obstruction of any kind, the structures of the mouth (most commonly, the soft palate, tongue, tonsils, and uvula) strike against each other and vibrate, and we hear the starts and snorts of snoring.
The tongue and throat structures must be flexible so that we can create the different sounds necessary for our language, and so that we can destroy a sirloin steak and sip caramel lattes with the same apparatus. But if the air passageways from the throat down to the lungs were a stiff tube, it would serve us better for the purpose of breathing. When we sleep, our muscles relax. The muscles that help keep the air passageways in our throat open during the day tend to constrict even for nonsnorers. The soft sides of the throat pull inward, and they vibrate like a flag rippling on a windy day.
Most of the causes of snoring are not sex-specific. Anything that promotes diminution of the muscle tone in the throat can lead to snoring, which is one of the reasons why most of the sleep specialists we consulted recommend eliminating smoking, drinking, and unnecessary pharmaceuticals (especially antidepressants, antihistamines, and ironically, sleeping pills). Overuse of drugs and alcohol results in loss of muscle tone that promotes vibrations in the throat. Smoking can cause a thickening of throat tissues, shrinking the area through which air can pass freely. While there is evidence that men overindulge in all of these “vices” more than women, smoking seems to affect the level of snoring equally in both sexes.
The most common risk factor in snoring is obesity. Obese people tend to have fatty deposits located below the mucous membranes in the throat that block proper airflow. Dr. Mansoor Madani, director of the Center for Corrective Jaw Surgery, in Bala Cynwyd, Pennsylvania (http://www.snorenet.com), told
Imponderables
that many of his patients are overweight and developed snoring problems only after becoming so. Many patients report snoring disappearing after significant weight losses. Although more men than women are obese, as with the “vices” listed above, it is not enough to explain the huge disparity in snoring rates.
Snoring is one condition in which bigger is definitely not better. If snorers experience periods of total breath obstruction during sleep (usually in between snorts), the condition is known as “obstructive sleep apnea” (or OSA). The single greatest predictor of sleep apnea is neck size. If your neck size is seventeen inches or greater, you have a thirty percent chance of suffering from sleep apnea.
Obviously, many more men than women have large necks, and there is some evidence that the structures inside the throats of large people are disproportionately bulky. According to Dr. Sunny Dong, a sleep specialist in British Columbia:
Women tend to have a shorter pharynx, which is less likely to vibrate during sleep. The soft palate is often thinner and the uvula is smaller, which makes the vibrations less loud and the frequency higher (which tends to make it less annoying).
As we age, the muscle tone in our throat tends to decrease, which results in more vibrations and snoring when sleeping. The tongue enlarges with age, which intensifies the problem. But Dr. Madani reports that the skin texture is firmer in women. Men’s throat tissue gets “floppier” as they get older.
The big controversy among sleep disorder specialists is the role of hormones in snoring. Some of the experts we consulted feel that medical science still can’t explain the etiology of men’s higher snoring rate. Dr. Andy Blockmanis, of the Pacific Center for Sleep Disorders in Vancouver, British Columbia, speculates that men’s greater weight, on average, may account for the snoring “gap,” and that women’s increase in snoring as they age may be attributed to their tendency to gain weight after menopause.
Most of the experts we consulted do believe that hormones affect snoring rates. They point to the obvious clue that the gender gap in the snoring rate narrows drastically after women undergo menopause, when almost as many women as men snore.
Dr. Dong points specifically to the role of progesterone, a female steroid sex hormone:
Before menopause, women have much higher progesterone levels than men and this hormone increases the tone in the airway muscles and increases respiratory drive, both of which lessen the tendency of the pharynx to collapse and vibrate. After menopause, the progesterone levels drop and more women begin to snore.
Anecdotal evidence supports the case for hormonal differences as a major factor. Dr. Christian Guilleminault, cofounder of the journal
SLEEP,
feels that women are protected from snoring by progesterone and estrogens, and points out that when women are treated with testosterone, this protection often disappears.
David Nye, a physician at the Midelfort Clinic in Eau Claire, Wisconsin, notes that androgens—male hormones—increase snoring. His partner, Donn Dexter, published a paper indicating that one female patient’s problems with sleep apnea were resolved after a testosterone-secreting tumor was removed in surgery.
Most of the treatments for snoring are not sex-specific. For some, eliminating vices such as smoking or drinking can solve the problems. Others find nasal sprays or air-flow masks helpful—more than 300 patents have been filed for snore-control devices. Many surgical procedures using knifes or lasers can alleviate snoring difficulties. Our favorite is “uvulopalatopharyngoplasty,” a procedure to reduce the size of the uvula, the soft palate, or both.
Why would someone go under the knife for uvulopalatopharyngoplasty for a problem as benign as snoring? Ask the significant other of the snorer. Several years ago, an Iranian man filed for divorce, accusing his wife of secretly drugging him so that he wouldn’t hear her snore. The wife admitted drugging her newlywed husband’s dinners; the husband caught on to her trick by skipping his usual evening meal one night. The wife of only forty days volunteered to sleep during the day and stay awake at night in order to save her marriage, but the reluctant groom rejected the proposal.
Submitted by Marlena Lynch of Fort Worth, Texas. Thanks also to Neil Young of Mill Valley, California.
