第四＋五篇 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
