首页
登录
职称英语
The collapse of the Earth’s magnetic field—which guards the planet and guide
The collapse of the Earth’s magnetic field—which guards the planet and guide
游客
2025-04-21
28
管理
问题
The collapse of the Earth’s magnetic field—which guards the planet and guides many of its creatures—appears to have started about 150 years ago, the New York Times reported last week.
The field’s strength has decreased by 10 or 15 percent so far and this has increased the debate over whether it signals a reversal of the planet’s lines of magnetic force.
During a reversal, the main field weakens, almost vanishes, and reappears with opposite polarity (极). The transition would take thousands of years. Once completed, compass needles that had pointed north would point south. A reversal could cause problems for both man and animals. Astronauts and satellites would have diffculties. Birds, fish and animals that rely on the magnetic field for navigation would find migration confusing. But experts links between past field reversals and species extinctions.
Although a total transition may be hundreds or thousands of years away, the rapid decline in magnetic strength is already affecting satellites. Last month, the European Space Agency approved the world’s largest effort at tracking the field’s shifts. Now a group of satellites called Swarm is to monitor the collapsing field with far greater precision. " We want to get some idea of how this would evolve in the near future, just like people trying to predict the weather, " said Gauthier Hulot , a French geophysicist working on the satellite plan. "I’m personally quite convinced we should be able to work out the first predictions by the end of the mission. "
No matter what the new findings, the public has no reason to panic. Even if a transition is coming on its way, it might take 2,000 years to mature. The last one took place 780,000 years ago, when early humans were learning how to make stone tools. Deep inside the Earth flow hot currents of melted iron. This mechanical energy creates electromagnet-ism. This process is known as the geophysical generator. In a car’s generator, the same principle turns mechanical energy into electricity.
No one knows precisely why the field periodically reverses. But scientists say the responsibility probably lies with changes in the disorderly flows of melted iron, which they see as similar to the gases that make up the clouds of Jupiter. [br] The cause of the transition of the Earth’s magnetic field comes from______.
选项
A、the movement deep inside the Earth
B、the periodical reverses of the Earth
C、the force coming from outer space
D、the mechanical movement of the Earth
答案
D
解析
本题考查考生的推断能力。文中最后一段的内容:没有人知道究竟为什么磁场会有周期性的转变。但是科学家认为这与地球深层的熔铁无序流动改变有关,这就类似于构成木星星云的气体。由此可以知道,D项符合题意。
转载请注明原文地址:http://tihaiku.com/zcyy/4047762.html
相关试题推荐
Newtechnologylinkstheworldasneverbefore.Ourplanethasshrunk.It’s
Newtechnologylinkstheworldasneverbefore.Ourplanethasshrunk.It’s
ThecollapseoftheEarth’smagneticfield—whichguardstheplanetandguide
ThecollapseoftheEarth’smagneticfield—whichguardstheplanetandguide
Newtechnologylinkstheworldasneverbefore.Ourplanethasshrunk.It’s
Newtechnologylinkstheworldasneverbefore.Ourplanethasshrunk.It’s
Granted,it’saprettyserioustimetobelivingonthisplanet.Insaneterro
Granted,it’saprettyserioustimetobelivingonthisplanet.Insaneterro
Granted,it’saprettyserioustimetobelivingonthisplanet.Insaneterro
ThenfeltlikesomewatcheroftheskiesWhenanewplanetswimsintohi
随机试题
Wewalkedsoquietlythatthenurseatthedeskdidn’tevenlifthereyesf
Whywasthewomannotatthemeeting?[br][originaltext]11.M:Inoticedy
ThediagrambelowshowstheprincipleofComing’sribbonmachine.Labelthediag
TheDifferencesBetweenAmericanandBritishEnglishI.Introduction
Self-discipline:theFoundationofProductiveLivingI.Issues
刺绣(embroidery)是中国艺术里一枚璀璨的珍珠。从君王所穿的华丽的龙袍(DragonRobe)到当今时尚界的流行刺绣,刺绣给我们的生活和文化增
[originaltext]Advertisementisthedifficultbusinessofbringinginformationt
下列著作中,属于张仲景所著的是()A.《伤寒杂病论》 B.《外科正宗》
建设项目方案研究与比选的工作包括:①研究与比选方案的初审;②选择研究与比选方法和
女,22岁。突然发热,腰痛,卧床不起。尿蛋白(一),红细胞10/HP,白细胞20
最新回复
(
0
)