首页
登录
职称英语
For 150 years scientists have tried to determine the solar constant, the amo
For 150 years scientists have tried to determine the solar constant, the amo
游客
2025-04-02
0
管理
问题
For 150 years scientists have tried to determine the solar constant, the amount of solar constant energy that reaches the Earth. Yet, even in the most cloud-free regions of the planet, the solar constant cannot be measured precisely. Gas molecules and dust particles in the atmosphere absorb and scatter sunlight and prevent some wavelengths of the light from ever reaching the ground.
With the advent of satellites, however, scientists have finally been able to measure the Sun’s output without being impeded by the Earth’s atmosphere. Solar Max, a satellite from the National Aeronautics and Space Administration(NASA), has been measuring the Sun’s output since February 1980. Although a malfunction in the satellite’s control system limited its observation for a few years, the satellite was repaired in orbit by astronauts from the space-shuttle in 1984. Max’s observations indicate that the solar constant is not really constant after all. The satellite’s instruments have detected frequent, small variations in the Sun’s energy output, generally amounting to no more than 0. 05 percent of the Sun’s mean energy output and lasting from a few days to a few weeks. Scientists believe these fluctuations coincide with the appearance and disappearance of large groups of sunspots on the Sun’s disk. Sunspots are relatively dark regions on the Sun’s surface that have strong magnetic fields and a temperature about 2, 000 degrees Fahrenheit cooler than the rest of the Sun’s surface. Particularly large fluctuations in the solar constant have coincided with sightings of large sunspot groups. In 1980, for example, Solar Max’s instruments registered 0. 3 percent drop in the solar energy reaching the Earth. At that time a sunspot group covered about 0. 6 percent of the solar disk, an area 20 times larger than the Earth’s surface.
Long-term variations in the solar constant are more difficult to determine. Although Solar Max’s data have indicated a slow and steady decline in the Sun’s output, some scientists have thought that the satellite’s aging detectors might have become less sensitive over the years, thus falsely indicating a drop in the solar constant. This possibility was dismissed, however, by comparing Solar Max’s observations with data from a similar instrument operating on NASA’s Nimbus 7 weather satellite since 1978. [br] Why is it not possible to measure the solar constant accurately without a satellite?
选项
A、the Earth is too far from the Sun.
B、Some areas on Earth receive more solar energy than others.
C、There is not enough sunlight during the day.
D、the Earth’s atmosphere interferes with the sunlight.
答案
D
解析
细节题。答案在第一段最后一句话,大意是即便是在地球上云层最少的地方,也很难测量准确,因为除了云层,还有气分子和灰尘粒子会影响阳光到达地球的量,因而对常数测量制作造成的影响。所以答案选D(地球大气层干扰了阳光的传播)。
转载请注明原文地址:https://tihaiku.com/zcyy/4023601.html
相关试题推荐
Therainwasheavyand______thelandwasflooded.A、constantlyB、ultimatelyC、con
For150yearsscientistshavetriedtodeterminethesolarconstant,theamo
For150yearsscientistshavetriedtodeterminethesolarconstant,theamo
Scientistsformerlyassumedthatcoralpopulationsremainedstable,deadpol
Alllivingcreatureshavetoconstantly______variouschangesintheirenvironmen
Thenumberoftickets______willbedeterminedbythesizeofthestadium.A、adapt
Whenadiseaseofepidemicproportionsripsintothepopulace,scientistsim
Whenadiseaseofepidemicproportionsripsintothepopulace,scientistsim
Whenadiseaseofepidemicproportionsripsintothepopulace,scientistsim
Whenadiseaseofepidemicproportionsripsintothepopulace,scientistsim
随机试题
Wefinishedallofthefoodatasitting.Theunderlinedpartmeans______.A、at
Duringthelastfewyears,therehasbeenan(36)______increaseinthenumb
男,50岁。腹胀、食欲减退半年。实验室检查WBC3.0×109/L,N0.60,
关于胸导联电极的安放,下列不正确的是A.V-胸骨右缘第四肋间 B.V-胸骨左缘
因脾阳不振,运化无权所致的水肿证,属于A、虚中夹实 B、实中夹虚 C、由虚转
心率过快时(>180次/分),心输出量下降的主要原因是A.快速射血期缩短 B.
商业银行利用衍生品可以完全对冲其所面临的市场风险,而且不会产生新的风险。()
甲搬家公司指派员工郭某为徐某搬家,郭某担心人手不够,请同乡蒙某帮忙。搬家途中,因
(2020年真题)甲、乙两家企业签订合作协议,协议约定:甲企业向乙企业每年支付5
下列属于施工机械使用管理"三定"内容的有()。A.定人 B.定机 C.定作
最新回复
(
0
)