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
In its first month orbiting Saturn, the Cassini spacecraft has detected a new radiation belt in an unexpected place, its invisib
In its first month orbiting Saturn, the Cassini spacecraft has detected a new radiation belt in an unexpected place, its invisib
admin
2021-10-20
58
问题
In its first month orbiting Saturn, the Cassini spacecraft has detected a new radiation belt in an unexpected place, its invisible swarm of trapped high-energy particles circling the planet inside the inner edge of Saturn’s signature disk of luminous rings.
Scientists who reported the discovery said yesterday that they were surprised to find a relatively small radiation belt completely isolated from a planet’s main radiation belts, which lie at much greater distances. They had not expected that such a concentration of energetic particles could be sustained inside the famous Saturnian rings.
The phenomenon of a single isolated belt, the scientists said, has never been observed at any other planet in the solar system. By contrast, the Van Allen belts of Earth consist of two related regions of intense radiation trapped by the planet’s magnetic field.
In a NASA conference call with reporters, Dr. Donald G. Mitchell, a Cassini mission scientist from Johns Hopkins University, said the newly discovered radiation belt was detected as the spacecraft made its closest approach to Saturn immediately after rocketing into its orbit on July 1. No previous spacecraft visiting Saturn had been in the proper position to make such a discovery.
Dr. Mitchell said it was the spacecraft’s imaging magnetometer that had observed the radiation belt, which extended around Saturn from about 15,000 miles above the planet’s cloud tops to the inner edge of the innermost of its spectacular rings. The belt is much smaller, and the energies of its particles are less intense, than Saturn’s main radiation belts.
With its discovery, Dr. Mitchell said, "we have seen something that we did not expect: that radiation belt particles can hop over obstructions like Saturn’s rings."
Other Cassini mission scientists reported puzzling patterns of lightning and thunderstorms on Saturn and observations of a striking glow emanating day and night from the planet’s largest moon, Titan.
What is special about the belt discovered latest?
选项
A、It is an insular belt which unexpectedly pierces through Saturnian rings.
B、It is much smaller and less intense than the formerly-discovered belts.
C、It is different from the Van Allen belts of Earth.
D、It is the outermost belt of Saturn.
答案
B
解析
原文第5段说:“发光带要小一些,粒子能量也不如土星主要发光带强。”故正确答案为B。A称该辐射带是孤立的,它出人意料地穿透了土星环;原文说到,辐射带的颗粒可以穿透土星环,二者并不一致,故不选A。C本身没错,但说它与地球上的范.艾伦辐带不同,并未揭示该辐射带的特点,与题意不符。D错误,该辐射带在土星环内侧,远比土星的主要辐射带低。
转载请注明原文地址:https://kaotiyun.com/show/2NtK777K
0
专业英语四级
相关试题推荐
ThisisathirdmemoirfromtheauthorFrankMcCourtwhohas【C1】______internationalreputationwithhisprevioustwobestseller
Thetableclearlyreflectsthestatisticsofjobsatisfactionofthestaffinacertaincompany.Accordingtothedatagivenin
Thetableclearlyreflectsthestatisticsofjobsatisfactionofthestaffinacertaincompany.Accordingtothedatagivenin
Thetableclearlyreflectsthestatisticsofjobsatisfactionofthestaffinacertaincompany.Accordingtothedatagivenin
Whichofthefollowingsentencesexpressesanopinion?
Weallseeandhearaboutextraordinarypeoplearoundusandwonderwhywecan’tbemorelikethem.Sometimeswechuckthatnoti
[A]school[B]numbers[C]emphasize[D]continue[E]significant[F]undoubtedly[G]weak[H]countries[I]invisible[J]ignore[K]unloc
A、Thepenaltyofnothavingthecarinsuranceisveryhigh.B、Themanisresponsibleforhisandtheotherdriver’sticket.C、Th
A、TohelpexploretheU.S.market.B、Toteachpsychologytoteenagers.C、Toopenasushirestaurantintown.D、Totreatteenager
A、Sheshouldhaveasupportivehusband.B、Shecantakeaslowapproach.C、Shecantakesomecoursesmoremarketable.D、Goingbac
随机试题
扁平结构和锥形结构的划分反映了()
符合溶血性黄疸特点的是
隧道围岩分级的综合评判方法根据()来确定隧道围岩分级。
填方工程中,若采用的填料具有不同透水性时,宜将透水性较大的填料( )。
新大华布艺公司在今年的财产清查中,盘亏材料90000元,可以收回的保险赔偿和过失人赔款合计20000元,剩余的净损失中有60000元属于非常损失,10000元属于自然损耗。还发现账外设备一台,估计原价为35000元,八成新。试为该企业做审批之前和审批之后的
四种基本类型的市场结构是()。
在上个打猎季节,在人行道上行走时被汽车撞伤的人数是在树林中的打猎事故中受伤的人数的2倍。因此,在上个打猎季节,人们在树林里比在人行道上行走时安全。为了评价上述论证,以下哪项是必须知道的?
关于侵犯商业秘密罪,下列说法正确的是()。
设A=E—2ξξT,其中ξ=(x1,x2,…,xn)T,且有ξTξ=1。则①A是对称矩阵;②A2是单位矩阵;③A是正交矩阵;④A是可逆矩阵。上述结论中,正确的个数是()
软件测试的目的是()。
最新回复
(
0
)