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明亮的夜晚,隐秘的星星

(2009-03-10 15:57:46)
标签:

国家地理

职称外语考试

光污染

星星

城市

分类: 世界网文摘译

 

2009年职称英语教材阅读理解新增部分(理工类)

 

1 Light Night, Dark Stars

明亮的夜晚,隐秘的星星

 

Thousands of people around the globe step outside to gaze at their night sky. On a clear night, with no clouds, moonlight, or artificial lights to block the view, people can see more than 14,000 stars in the sky, says Dennis Ward, an astronomer with the University Corporation for Atmospheric Research (UCAR) in Boulder, Colo 1 . But when people are surrounded by city lights, he says, they're lucky to see 150 stars.

全球各地成千上万的人们超出户外凝视着天空。科罗拉多州玻尔市的大学大气研究社团的天文学家丹尼斯·沃特说,在一个明亮的夜晚,万里无云,或许人造光防碍了观察,人们至少能看到天空里的14000颗星星。但是,他说当人们置身城市灯光里,他们运气好时能看到150个星星。

 

If you've ever driven toward a big city at night and seen its glow from a great distance, you've witnessed light pollution. It occurs when light from streetlights, office buildings, signs, and other sources streams into space and illuminates the night sky. This haze of light makes many stars invisible to people on Earth. Even at night, big cities like New York glow from light pollution, making stargazing2 difficult.

如果你曾经在晚上驾车到过一个大城市,并且远远地看到过它的光辉,你肯定见识过光污染。它的产生是因为街灯、办公大楼、标志物、以及其它光源发出的光射入空中并照亮了夜空。这层光雾使得许多星星在地球上看不见了。即使在夜晚,象纽约这样的大城市因光污染而灯火通明,使得观望星星困难。

Dust and particles of pollution from factories and industries worsen the effects of light pollution. "If one city has a lot more light pollution than another," Ward says, "that city will suffer the effects of light pollution on a much greater scale. "

来自工厂和其它行业的污染的灰尘和颗粒使光污染的效果恶化。“如果一个城市比另一人的光污染量更大,”沃物说,“这个城市遭受更大程度的光污染影响。”

Hazy skies also make it far more difficult for astronomers to do their jobs.

朦胧的天空也天文学家更加难以完成他们的工作。

Cities are getting larger. Suburbs are growing in once dark, rural areas. Light from all this new development is increasingly obscuring the faint light given off by distant stars. And if scientists can't locate these objects, they can't learn more about them.

城市越来越大。市郊区向曾经黑暗的乡下地区扩张。从所有这些新开发区发出的光使从愈加遥远的星星发出的暗淡的光愈加模糊。并且,如果科学家不能定们这些目标,他们无法更多地了解它们。

Light pollution doesn't only affect star visibility. It can harm wildlife too. It's clear that artificial light can attract animals, making them go off course3. There's increasing evidence, for example, that migrating birds use sunsets and sunrises to help find their way, says Sydney Gauthreaux Jr., a scientist at Clemson University in South Carolina. "When light occurs at night," he says, "it has a very disruptive influence. " Sometimes birds fly into lighted towers, high-rises, and cables from radio and television towers. Experts estimate that millions of birds die this way every year.

光污染不仅仅影响星星的可见度,也会伤害野生动物。众所周知,人造光能吸引动物,使它们偏离飞行路线。例如,越来越多的证据表明候鸟应用日落和日出来找到飞行的路线。

 

2 Hair Detectives

头发侦探

Scientists have found a way to use hair to figure out where a person is from and where that person has been. The finding could help solve crimes, among other useful applications.

科学家已经发现了应用头发描绘出了一个人来自哪里、以及这人在哪里。在其它有益的运用中,这个发现可能有助于解决犯罪案件。

 

Water is central to the new technique. Our bodies break water down into its parts: hydrogen and oxygen. Atoms of these two elements end up in our tissues and hair.

水是这种新技术的关键。我们的身体把水分解成它的成份:氢和氧。这两种元素的原子最终进入了我们的组织和头发。

 

But not all water is the same. Hydrogen and oxygen atoms can vary in how much they weigh. Different forms of a single element are called isotopes. And depending on where you live, tap Water1 contains unique proportions of the heavier and lighter isotopes of hydrogen and oxygen.

但是,不是所有的水都是一样的。氢和氧原子可能在重量上多少有点变化。单个元素的不同形式称为同位素。而依赖于你生活的地方,自来水含有特殊的比例的氢与氧的较重与较轻的同位素。

 

Might hair record these watery quirks2? That's what James R. Ehleringer, an environmental scientist at the University of Utah in Salt Lake City3, wondered.

头发也许记录了这些水的古怪特点吗?这就是盐湖城的犹他大学一位环境学家詹姆斯·R·伊尔林格想探究的问题。

 

To find out, he and his colleagues collected hair from barbers and hair stylists in 65 cities in 18 states across the United States. The researchers assumed that the hair they collected came from people who lived in the area.

为了找出答案,他和同事们从理发店和发形师那里收集了头发,范围遍及美国18个州65个城市。这些研究人员假定他们收集的头发来自生活在这个地区的人们。

 

Even though people drink a lot of bottled water these days, the scientists found that hair overwhelmingly reflected the concentrations4of hydrogen and oxygen isotopes in local tap water. That's probably because people usually cook their food in the local water. What's more, most of the other liquids people drink including milk and soft drinks contain large amounts of water that also come from sources within their region.

即使人们这些天喝了大量的瓶装水,科学家发现,头发压倒性地反映了当地自来水的氢和氧同位素的浓度。这可能是因为人们通常用当地的水烹调食物。更多的是,人们喝的包括牛奶和软饮料的大多数其它液体,含有大量也来源于他们那个区域的水。

 

Scientists already knew how the composition of water varies throughout the country. Ehleringer and colleagues combined that information with their results to predict the composition of hair in people from different regions. One hair sample used in Ehleringer's study came from a man who had recently moved from Beijing, China, to Salt Lake City. As his hair grew, it reflected his change in location.

科学家已经知道全国各地水的成份变化情况。伊尔林格和同事们把那些信息与不同地区人们的头发成份预测的结果相结合。用于伊尔林格的研究的一个头发样本,来自最近从中国北京搬到盐湖城的男人。当他的头发长起来后,样本反映了他的地域改变。

 

The new technique can't point to exactly where a person is from, because similar types of water appear in different regions that span a broad area. But authorities can now use the information to analyze hair samples from criminals or crime victims and narrow their search for clues.

这种新技术不能严格地指出一个人来自哪里,因为水的相似类型出现在纵贯一个广阔区域的不同地区。但是,现在作者能够应用这些信息来分析罪犯或受害者的头发样本,缩小他们对线索的搜寻。

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