首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
外语
For 150 years scientists have tried to determine the solar constant, the amount of solar constant energy that reaches the Earth.
For 150 years scientists have tried to determine the solar constant, the amount of solar constant energy that reaches the Earth.
admin
2017-05-11
64
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.
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://kaotiyun.com/show/OxFO777K
0
考博英语
相关试题推荐
Whatissospecialaboutintuitivetalent?Extensiveresearchonbrainskillsindicatesthatthosewhoscoreashighlyintuitive
ManyadvocatesofauniversalhealthcaresystemIntheUnitedStateslooktoCanadafortheirmodel.WhiletheCanadianhealthca
Forthefirsttime,wefound____thatallowustoconnectthefirstphaseofhumanevolutionandthesecondphase.
Therehasbeena_____lackofcommunicationbetweentheunionandthemanagement.
InJuly,almostunnoticedbythenationalpress,adeadlybirdvirusarrivedonapheasantfarminSurrey.ExpertsfromtheDepa
Eachyear,millionsofpeopleinBangladeshdrinkgroundwaterthathasbeenpollutedbynaturallyhighlevelsofarsenicpoison.
Eachyear,millionsofpeopleinBangladeshdrinkgroundwaterthathasbeenpollutedbynaturallyhighlevelsofarsenicpoison.
AWorldWithoutBooksOrMusicIfbookshadneverbeendiscovered,manwouldhavefoundsomeotherwayofrecordinghiscomm
Oncethe____contradictionisgrasped,allproblemswillbereadilysolved.
AlthoughtheArabcutbacksrepresentedalossoflessthan7percentinworldsupply,theycreatedpaniconthepartofoilcompa
随机试题
内部控制要素包括()
简述启动资源管理器的方法。
对于拔牙后要求进行牙槽骨修整的患者,合适的手术时间是
蟾酥的药用部位是
医务人员对患者的态度会成为
A.作用于髓袢升支粗段皮质部,抑制Na+-Cl-共同转运系统B.作用于髓袢升支粗段的髓质和皮质部,抑制Na+-K+-2Cl-共同转运系统C.作用于近曲小管,抑制碳酸酐酶,减少H+-Na+交换D.作用于远曲小管和集合管,竞争醛固酮受体,对抗醛固酮
保护线截面均应满足:有机械保护时最小截面为2.5mm2,没有机械保护时最小截面为4mm2。包括含在供电电缆中的保护导体及用电缆外护物金属作保护导体。()
全国人民代表大会解释宪法,监督宪法的实施。()
根据所给资料,回答以下问题。据初步统计,2013年我国全年水资源总量25567亿立方米,比上年减少8.9%,比常年减少7.7%;人均水资源量1945立方米,比上年减少9.3%;全年平均降水量615.5毫米,较上年减少4.5%,比常年减少4.2%。年末
Everyday,thousandsofmanagers,bankers,sales-executives,lawyers,accountants,andotherprofessionalsaredriventoangera
最新回复
(
0
)