时间:2012-03-31 22:40:48
Small But Wise
On December 14,NASA1 blasted a small but mighty telescope into space. The telescope is called WISE and is about as wide around as a trashcan. Don't let its small size fool you:WISE has a powerful digital camera, and it will be taking pictures of some the wildest objects2 in the known universe,including asteroids,faint stars,blazing galaxies3 and giant clouds of dust where planets and stars are born.
"I'm very excited because we're going to be seeing parts of the universe that we haven't seen before,"said Ned Wright, a scientist who directs the WISE project.
Since arriving in space,the WISE telescope has been circling the Earth,held by gravity in a polar orbit4(this means it crosses close to the north and south poles with each lap5).Its camera is pointed outward,away from the Earth,and WISE will snap a picture of a different part of the sky every 11 minutes. After six months it will have taken pictures across the entire sky.
The pictures taken by WISE won't be like everyday digital photographs,however. WISE stands for"Wide-field Infrared Survey Explorer."As its name suggests,the WISE camera takes pictures of features that give off infrared radiation6.
Radiation is energy that travels as a wave. Visible light, including the familiar spectrum of light7 that becomes visible in a rainbow,is an example of radiation. When an ordinary digital camera takes a picture of a tree,for example,it receives the waves of visible light that are reflected off the tree. When these waves enter the camera through the lens,they're processed by the camera,which then puts the image together.
Waves of infrared radiation are longer than waves of visible light, so ordinary digital cameras don't see them,and neither do the eyes of human beings. Although invisible to the eye,longer infrared radiation can be detected as warmth by the skin.
That's a key idea to why WISE will be able to see things other telescopes can't. Not everything in the universe shows up in visible light. Asteroids,for example,are giant rocks that float through space 一but they absorb most of the light that reaches them. They don't reflect light,so they're difficult to see. But they do give off infrared radiation, so an infrared telescope like WISE will be able to produce images of them. During its mission WISE will take pictures of hundreds of thousands of asteroids.
Brown dwarfs8 are another kind of deep-space object that will show up in WISE's pictures. These objects are"failed" stars 一which means they are not massive enough to jump start9 the same kind of reactions that power stars such as the sun. Instead,brown dwarfs simply shrink and cool down. They're so dim that they're almost impossible to see with visible light, but in the infrared spectrum they glow.
词汇：
trashcan / 'træʃ,kæn/n．垃圾箱
infrared/'infrə'red/ adj．红外线
asteroid/'æstərɔid/ n.小行星
dwarf/dwɔ:f/ n. 矮星
注释：
1.NASA （美国国家航空航天局）是缩写词，全称是National Aeronautics and Space
Administration
2. the wildest objects ：任何你能想象得到的天体。wild 有“未被人驯养的”“荒唐的”“离奇的”意思。
3. faint stars, blazing galaxies：指的是那些只能看到微弱的光和因燃烧而无法观察到的天体。
4. polar orbit：极地轨道。指轨道平面与赤道面夹角为90。的人造地球卫星轨道。人造卫星运行时能到达南北极区上空，即卫星能飞经全球范围的上空。需要在全球范围内进行观测和应用的气象卫星、导航卫星、地球资源卫星等都采用这种轨道。
5. lap：一圈。原指竞赛场的一圈或游泳池的一个来回，如： She overtook the other runners on the last lap. 她最后一圈超过了其他参赛者。
6. infrared radiation：红外线辐射
7. spectrum of light：光谱，即，光辐射的波长分布区域。
8. Brown dwarfs：褐矮星。褐矮星非常暗淡，很难发现它们，要确定它们的大小就更加困难。
9.jump start: 启动