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Small But Wise On December 14, NASA blasted a small but mighty telescope in...

admin2020-12-24  35
问题 Small But Wise
On December 14, NASA blasted a small but mighty telescope into space. The telescope is called WISE and is about as wide around as a trashcan (垃圾箱）. Don’t let its small size fool you: WISE has a powerful digital camera, and it will be taking pictures of some of the wildest objects in the known universe，including asteroids (小行星），faint stars， blazing galaxies 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 Eatlh，held by gravity in a polar orbit (this means it crosses close to the north and south poles with each lap). 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 entiresky.
The pictures taken by WISE won’t be like everyday digital photographs，however, WISE stands for “Wide-field lnfrared (红外线的)Survey Explorer."As its name suggest, WISE camera takes pictures of features that give off infrared radiation.
Radiation is energy that travels as a wave. Visible light，including the familiar spectrum of light 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 wavM that are reflected off the tree. When these waves enter the camera through the lens, they’re processedbythecamera，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 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 "ght. Asteroids，for example，are gia时 that float through space — 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 Mrared 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 dwarfs (矮星）are another kind of deep-space object that will show up in WISE’s pictures. These objects are “failed” stars — which means they are not massive enough to jump start 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 Mrared spectrum they glow.
It is true that infrared radiation
选项 A is not detectable to humans.
B looks brighter than visible lght.
C is visible light reflected off an object.
D have longer waves than those of visible light.
答案D
解析根据第六段的叙述，A、B 显然不对。
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