Thetemperatureofthesunisover5000degreesFahrenheitatthes...
问题详情:
The temperature of the sun is over 5000 degrees Fahrenheit at the surface, but it rises to perhaps more than 16 million degrees at the center.The sun is so much hotter than die earth that matter can exist only as a gas, except at the core.In the core of the sun, the pressures are so great against the gases that, despite the high temperature, there may be a small solid core.However, no one really knows, since the center of the sun can never be directly observed.
Solar astronomers do know that the sun is divided into five layers or zones.Starting at the outside and going down into the sun, the zones are the corona, chromosphere, photosphere, convection zone and finally the core.The first three zones are regarded as the sun's atmosphere.
But since the sun has no solid surface, it is hard to tell where the atmosphere ends and the main
body of the sun begins.
The sun's outermost layer begins about 10000 miles above the visible surface and goes outward for mllions of miles.This is the only part of the sun that can be seen during an eclipse(日食) such as the one in February 1979.At any other time, the corona can be seen only when special instruments are used on cameras and telescopes to shut out the glare of the sun's rays.
The corona is a brilliant, pearly white, filmy light, about as bright as the full moon.Its beautiful rays are a sensational sight during an eclipse.The corona's rays flash out in a brilliant fan that has wispy spikelike(一束束穗状) rays near the sun's north and south poles.The corona is thickest at the sun's equator.
The corona rays are made up of gases streaming outward at tremendous speeds and reaching a temperature of more than 2 million degrees Fahrenheit.The rays of gas thin out as they reach the space around the planets.By the time the sun's corona rays reach the Earth, they are weak and invisible.
1.Matter on the sun can exist only in the form of gas because of the sun's ___.
A.size B..age C.location D.temperature
2.All of the following are parts of the sun's atmosphere EXCEPT the ___.
A.corona B.chromosphere C.photosphere D.core
3.According to the passage, as the corona rays reach –the planets, they become ___.
A.hotter B.clearer C.thinner D.stronger
4.Which of the following do the paragraphs following the passage most likely discuss?
A.The remaining layers of the sun.
B.The evolution of the sun to its present form.
C.The eclipse of February 1979.
D.All the above.
【回答】
DDCA
知识点:阅读理解
题型:未分类
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设,若,则a=( )A.-1 B.0 C.2 D.3
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问题详情:“吃得营养、吃出健康”是人们普遍的饮食追求,下列说法不正确的是A.人每天都应摄入一定量的蛋白质B.过量食用油脂能使人发胖,故应禁止摄入油脂C.糖类是人体能量的重要来源D.过量摄入微量元素不利于健康【回答】B知识点:各地中考题型:选择题...
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