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
2023-11-09
36
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] 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://tihaiku.com/zcyy/3171872.html
相关试题推荐
Themerchantspacecraftismeantto______.[br][originaltext]It’s60feet
Themerchantspacecraftismeantto______.[originaltext]It’s60feetlong,
Thecountryhasalreadysentupthreeunmannedspacecraft,themostrecent______
InitsfirstmonthorbitingSaturn,theCassinispacecrafthasdetectedane
InitsfirstmonthorbitingSaturn,theCassinispacecrafthasdetectedane
InitsfirstmonthorbitingSaturn,theCassinispacecrafthasdetectedane
Howtalldidthespacecraftmakethefreefall?[br][originaltext]Ifonero
Howtalldidthespacecraftmakethefreefall?[originaltext]Ifonerockets
Themerchantspacecraftismeantto[br][originaltext]It’s60feetlong,m
Themerchantspacecraftismeantto[originaltext]It’s60feetlong,madeof
随机试题
Thebiggestsafetythreatfacingairlinestodaymaynotbeaterroristwith
[originaltext]Inthelastfewyears,thefaceofundocumentedimmigrationt
下列关于净稳定资金比率的叙述中,正确的有()。A.NSFR=(可用稳定资金÷所需
主产于山东的药材是A.滑石 B.自然铜 C.石膏 D.芒硝 E.
为男性病人导尿过程中出现导尿管插入受阻,应该采取以下哪种措施A、拔出导尿管重新插
2017年3月31日,大理白族自治州人民政府发布公告:即日起,洱海流域水生态保护
低碳城市是一个新生事物,没有现成可借鉴的模式。专家指出,对低碳经济的认识问题上,
(2015年真题)地下水环境监测点布设应遵循的原则有()。A.以项目地区为
下列炎症介质中,具有趋化作用的是A.缓激肽 B.前列腺素 C.NO D.I
某项目在工程初期很难描述工作范围和性质,或工期紧迫,无法按常规编制招标文件招标时
最新回复
(
0
)