VOA标准英语2008年-Scientists Solve Mystery of Brilliant Northern,

Scientists have solved the mystery behind the brilliant northern and southern light show known as Aurora¹ Borealis. The phenomenon is caused by electromagnetic energy from the sun, which experts say also wreaks² havoc³ on ground-based power grids⁴ and satellites. VOA's Jessica Berman reports.

Just like atmospheric⁵ conditions can affect weather on the ground, experts say the sun is responsible for weather in outer space.

They say the Sun's atmosphere emits high energy solar winds that bathe the Earth continuously with electromagnetic energy.

Nicola Fox is with the Johns Hopkins University Applied⁶ Physics Laboratory in Laurel, Maryland.

"You could really think of it as us living in the atmosphere of the Sun," Fox explained. "So, if the Sun changes, the Earth will feel its effects. So, if the Sun sneezes, the Earth will catch a cold."

But until now, space scientists have been unable to pinpoint⁷ the source of energy releases in the earth's atmosphere that are responsible for the spectacular light show, aurora borealis, in the extreme northern and southern latitudes⁸.

The same energy releases are responsible for dangerous sub-storms that disrupt ground-based power grids and communications systems.

Scientists at the University of California at Los Angeles discovered the source of the space blasts using five satellites of the U.S. space agency's THEMIS program.

The researchers explain that the Sun's and Earth's electromagnetic fields normally glide⁹ past one another in many different directions.

But when enough energy builds between the two fields, they snap and right themselves in a process scientists call reconnection.

David Sibek is THEMIS project scientist with the U.S. space agency NASA.

He says reconnection releases a huge amount of electrical current into the magnetosphere that surrounds the planet.

"When reconnection occurs, that current is broken and it flows down to the Earth so you have like a short-circuit out in the Earth's magnetic field," explained Sibek. "And it's that current that's going to power the aurora and dump into the Earth's ionosphere and cause power line disruption in Canada for example by blowing out transformers."

Scientists say it is important to know about sub-storms in order to take measures to protect valuable technical equipment, and possibly the lives of spacewalking astronauts.

The discovery of the mechanism¹⁰ behind sub-storms is reported in the journal Science.

 

1 aurora   

n.极光

参考例句：

• The aurora is one of nature's most awesome spectacles.极光是自然界最可畏的奇观之一。
• Over the polar regions we should see aurora.在极地高空,我们会看到极光。

2 wreaks   

诉诸（武力），施行（暴力），发（脾气）( wreak的第三人称单数 )

参考例句：

• Worshipping the sun wreaks havoc on skin. So does smoking. 过度晒太阳会毁掉好皮肤，吸烟也是如此。
• His hard work wreaks havoc in his personal life. 他拼命工作破坏了他的私人生活。

3 havoc   

n.大破坏，浩劫，大混乱，大杂乱

参考例句：

• The earthquake wreaked havoc on the city.地震对这个城市造成了大破坏。
• This concentration of airborne firepower wrought havoc with the enemy forces.这次机载火力的集中攻击给敌军造成很大破坏。

4 grids   

n.格子( grid的名词复数 )；地图上的坐标方格；（输电线路、天然气管道等的）系统网络；（汽车比赛）赛车起跑线

参考例句：

• Typical framed structures are beams, grids, plane and space frames or trusses. 典型构架结构为梁、格栅、平面的和空间的框架或桁架。 来自辞典例句
• The machines deliver trimmed grids for use or stock. 这种机器铸出修整过的板栅，以供使用或储存。 来自辞典例句

5 atmospheric   

adj.大气的，空气的；大气层的；大气所引起的

参考例句：

• Sea surface temperatures and atmospheric circulation are strongly coupled.海洋表面温度与大气环流是密切相关的。
• Clouds return radiant energy to the surface primarily via the atmospheric window.云主要通过大气窗区向地表辐射能量。

6 applied   

adj.应用的；v.应用，适用

参考例句：

• She plans to take a course in applied linguistics.她打算学习应用语言学课程。
• This cream is best applied to the face at night.这种乳霜最好晚上擦脸用。

7 pinpoint   

vt.准确地确定；用针标出…的精确位置

参考例句：

• It is difficult to pinpoint when water problems of the modern age began.很难准确地指出，现代用水的问题是什么时候出现的。
• I could pinpoint his precise location on a map.我能在地图上指明他的准确位置。

8 latitudes   

纬度

参考例句：

• Latitudes are the lines that go from east to west. 纬线是从东到西的线。
• It was the brief Indian Summer of the high latitudes. 这是高纬度地方的那种短暂的晚秋。

9 glide   

n./v.溜，滑行；(时间)消逝

参考例句：

• We stood in silence watching the snake glide effortlessly.我们噤若寒蝉地站着，眼看那条蛇逍遥自在地游来游去。
• So graceful was the ballerina that she just seemed to glide.那芭蕾舞女演员翩跹起舞，宛如滑翔。

10 mechanism   

n.机械装置；机构，结构

参考例句：

• The bones and muscles are parts of the mechanism of the body.骨骼和肌肉是人体的组成部件。
• The mechanism of the machine is very complicated.这台机器的结构是非常复杂的。