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Monahans 1998 means that little green men are coming soon to a planet near us.
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The Johnson Space Center reported the discovery in the journal Newsweek.
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Ancient Water From Afar
It streaked across the sky on a warm March evening last year, then crashed into a street in the small town of Monahans, Texas. When seven boys quit their basketball game to inspect the damage, they found a shiny, black grapefruit-size rock settled in the asphalt (沥青). Word of the “flaming rock” traveled quickly in newspapers and on TV. The next day, NASA scientist Everett Gibson arrived and took the meteorite(陨石) , later named Monahans 1998, back to a lab in Houston. There researchers broke open the extraterrestrial (地球外的)rock with a hammer and chisel (凿子). To their surprise, they struck water. A team led by Michael Zolensky of the Johnson Space Center reports this discovery in a journal. It’s the first time anyone has found liquid water in an object from space—and a suggestion that life may exist out side our planet.
Meteorites containing water are probably not scarce, Zolensky says. But by the time researchers get their hands on the rocks, minerals that trap the water have dissolved away, and the water have evaporated. Worse, some researchers destroy the evidence by cutting meteor ites open with rock saws and water. “I’m betting this isn’t such a rare finds it’s just that people have been mistreating their meteorites,” Zolensky says.
Of course, Zolensky’s team did get a bit lucky. Monahans 1998 was safe in their lab less than two days after it hit the Earth, so they examined an unusually fresh sample. The scientists were keen to find vivid purple crystals of halite (岩盐)inside the meteorite, since halite is a salt mineral usually formed from liquid water. Even more curious were the hundreds of tiny bubbles suspended in the halite crystals. Zolensky’s team analyzed the bubbles by shining a laser beam through them and confirmed they were made of salty brine (盐水).
By dating the halite, Zolensky’s team found the water trapped inside it formed at least 4.5 billion years ago, back when most scientists believe our solar system was born. That means the briny object amy help researchers learn about the gaseous nebulas(星云)that gave rise to our sun and planets.
But how did the meteorite get wet？ One possibility is that a passing comet smashed into the rock, dropping off a load of liquid water. Or the rock might have chipped off an asteroid (小行星)that holds pools of fluid. Zolensky’s team still needs to study whether the water comes from our own solar system. One thing is certain, however: the Monahans meteorite will fuel the debate on extraterrestrial life, “Water is a life-giver, so if you want to study where life came from in the solar system, you have to follow where water came from,” Zolensky says. A wet rock from space doesn’t mean little green men are coming soon to a planet near you, but it does raise hopes that we’re not alone in the universe.
Scientist find liquid water inside the rock.
Food and Health
The food you eat does more than provide energy. It can have a dramatic effect on your body’s ability to fight off heart disease, cancer, diabetes, high blood pressure, stroke, and weak bones. With remarkable consistency, recent research has found that a diet high in plant-based foods—fruits, vegetables, dried peas and beans, grains, and starchy staples such as potatoes—is the body’s best weapon in thwarting many health-related problems. These foods work against so many diseases that the same healthy ingredients you might use to protect your heart or ward off cancer will also benefit your intestinal tract and bones.
Scientists have recently estimated that approximately 30 to 40 percent of all cancers could be avoided if people ate more fruits, vegetables, and plant-based foods and minimized high-fat, high-calorie edibles that have scant nutritional value. Up to 70 percent of cancers might be eliminated if people also stopped smoking, exercised regularly, and controlled their weight. In the past, researchers had linked fat consumption with the development of cancers, but they currently believe that eating fruits, vegetables, and grains may be more important in preventing the disease than not eating fat. “The evidence about a high-fat diet and cancer seemed a lot stronger several years ago than it does now,” says Melanie Polk, a registered dietitian and director of nutrition education at the American Institute for Cancer Research.
The road to strong bones is paved with calcium-rich food. Leafy green vegetables and low-fat dairy products are excellent sources of calcium, the mineral that puts stiffness into your skeletal system and keeps your bones from turning rubbery and fragile. Your body uses calcium for more than keeping your bones strong. Calcium permits cells to divide, regulates muscle contraction and relaxation, and plays an important role in the movement of protein and nutrients inside cells. If you don’t absorb enough from what you eat to satisfy these requirements, your body will take it from your bones. Because your body doesn’t produce this essential mineral, you must continually replenish the supply. Even though the recommended daily amount is 1,200 mg, most adults don’t eat more than 500 mg. One reason may have been the perception that calcium-rich dairy products were also loaded with calories. “In the past, women, in particular, worried that dairy products were high in calories,” says Letha Y. Griffin, M. D., of Peachtree Orthopaedics in Atlanta. “But today you can get calcium without eating any high-fat or high-calorie foods by choosing skim milk or low-fat yogurt.” Also, low fat dairy products contain phosphorous and magnesium and are generally fortified with vitamin D, all of which help your body absorb and use calcium. If you find it difficult to include enough calcium in your diet, ask your doctor about supplements. They’re a potent way to get calcium as well as vitamin D and other minerals. But if you rely on pills instead of a calcium-rich diet, you won’t benefit from the other nutrients that food provides. Getting the recommended vitamin D may be easy, since your body makes the vitamin when your skin is exposed to the sun’s rays.
Which kind of food is recommended to prevent heart disease, cancer, diabetes, high blood pressure, stroke, and weak bones？______
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