首页
登录
职称英语
In its first month orbiting Saturn, the Cassini spacecraft has detected a ne
In its first month orbiting Saturn, the Cassini spacecraft has detected a ne
游客
2024-08-30
10
管理
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. [br] Why couldn’t the radiation belt be found earlier?
选项
A、Because visual angles are different.
B、Because spacecrafts didn’t approach Saturn close enough in the past.
C、Because viewing spot matters.
D、Because the spacecraft had no imaging magnetometer advanced enough in the past.
答案
C
解析
第4段中“先前探测土星的飞船没有到达适当的位置而没有作出如此发现。”说明先前飞船都没有如此的发现是由于position不适当。C中的spot正是此义。注意理解viewing spot matters是“观察位置问题”之义。
转载请注明原文地址:https://tihaiku.com/zcyy/3736167.html
相关试题推荐
InitsfirstmonthorbitingSaturn,theCassinispacecrafthasdetectedane
InitsfirstmonthorbitingSaturn,theCassinispacecrafthasdetectedane
InitsfirstmonthorbitingSaturn,theCassinispacecrafthasdetectedane
随机试题
Completethesentencesbelow.WriteNOMORETHANTWOWORDSforeachanswer.Job
A.abuseB.acquiredC.affectD.appreciatedE.attractedF
裱糊工程各幅拼缝应严密,距墙面( )m处正视时,如不显拼缝即符合要求。A.1.
围绕范围管理,下列说法中,()是正确的。A.收集需求采用的工具有问卷调查和文件
某网友将小明的家庭住址、电话号码登在公共论坛上,这侵犯了小明的哪项权利?()
人在每一瞬间,将心理活动选择了某些对象而忽略了另一些对象。这一特点指的是注意的(
生产、销售劣药,有拒绝、逃避监督检查的行为,但还不能认定为“对人体健康造成严重危
共用题干 2002年11月19日,朱镕基同志在第16届世界会计师大会闭幕式上的
工艺过程中产生的静电可能引起爆炸和火灾,也可能给人以电击,还可能妨碍生产。下列燃
某中年人,童年生活受挫折,个性克制,情绪压抑,经常焦虑、抑郁,又不善于宣泄,过分
最新回复
(
0
)