The Cause of Auroras托福红Delta听力原文翻译及问题答案

The Cause of Auroras托福红Delta听力原文翻译及问题答案，今天中国教育在线就来为大家分析这个问题。

一、The Cause of Auroras托福红Delta听力原文：

W:For centuries,people have told stories to explain the moving lights in the night sky—the curtains of greenish-white light with pink fringe.People described these lights as the breath of the Earth,powerful spirits,or angel light.An early twentieth-century explorer wrote about the“bloody red”and“ghostly green”lights.These lights,of course,are the aurora borealis—the northern lights—and,in the south,the aurora australis.Most of the time they’re greenish-yellow,but sometimes they take colors from violet to red.The auroras can be seen at any time of the year,with the right atmospheric conditions.They’re most often seen near the North and South Poles,during times of maximum solar activity.The closer to the North or South Pole you are,the better you can see the lights.

The auroras occur in the ionosphere.The ionosphere is the layer of the upper atmosphere where high-energy solar radiation strips electrons from oxygen and nitrogen atoms,and leaves them as positively charged ions.The auroras are the result of a complex interaction between the solar wind and the Earth’s magnetic field.Here’s what happens.The sun’s heat charges the particles in the solar wind,a stream of electrically charged subatomic particles that continually emanates from the sun.As the solar wind approaches Earth,it’s deflected by Earth’s magnetic field and diverted north and south toward the magnetic poles.The interaction between the solar wind and the magnetosphere generates beams of electrons.These electrons collide with atoms and molecules within the ionosphere near Earth’s magnetic poles.The collisions rip apart molecules and excite atoms.Thus,oxygen and nitrogen atoms in the ionosphere become“excited,”or ionized.The auroras happen when these ionized atoms return to their normal state from their excited,energized states.The ions combine with free electrons—as they do so,they emit radiation.Part of this radiation is visible light:the aurora borealis and aurora australis.Yes,Simon?

M:Uh...it sounds kind of like electricity.

W:Yes,that’s right.The auroras are an electricalphenomenon.As you know,an electrical generator has two components:a conductor and a magnetic field.To generate electricity,the conductor has to move across the field to produce a force.With the auroras,the conductor is the solar wind carrying a stream of charged particles.

M:So,what happens is,when,uh,when the charged particles reach Earth’s magnetic field,they,uh,move along in the field towards the north and south magnetic poles.

W:Exactly.And then the particles collide with gases in the atmosphere—oxygen and nitrogen—and the oxygen and nitrogen atoms get excited.And then,when the particles get de-excited and return to their normal state,they emit the auroras by releasing energy in the form of light.Oxygen releases either dark red or ghostly green.Nitrogen emits rosy pink or magenta.The activity of the auroras varies with the sun’s activity.When the sun is quiet,the auroras can be seen only in a small area.When the sun is active,however,the aurora borealis can be seen across southern Canada and the northern United States.

二、The Cause of Auroras托福红Delta听力中文翻译：

W：几个世纪以来，人们一直在讲故事来解释夜空中移动的灯光——带粉红色条纹的绿白色光幕。人们把这些光描述为地球的气息、强大的灵魂或天使之光。二十世纪早期的一位探险家写下了“血红”和“幽灵绿”的光。当然，这些光是北极光，北极光，南极光。大多数时候它们是绿黄色的，但有时它们的颜色从紫色变为红色。在适当的大气条件下，一年中的任何时候都可以看到极光。在太阳活动最活跃的时候，它们最常出现在北极和南极附近。你离北极或南极越近，你就能越清楚地看到灯光。

极光出现在电离层。电离层是高层大气的一层，高能太阳辐射将氧原子和氮原子中的电子剥离出来，留下带正电的离子。极光是太阳风和地球磁场之间复杂相互作用的结果。下面是发生的情况。太阳的热量给太阳风中的粒子充电，太阳风是一股带电的亚原子粒子流，不断从太阳中散发出来。当太阳风接近地球时，它被地球磁场偏转，转向南北向磁极。太阳风和磁层之间的相互作用产生电子束。这些电子与地球磁极附近电离层中的原子和分子发生碰撞。碰撞撕裂分子并激发原子。因此，电离层中的氧和氮原子被“激发”或电离。当这些电离原子从激发态、激发态恢复到正常状态时，就会出现极光。离子与自由电子结合时，会发出辐射。这种辐射的一部分是可见光：北极光和南极光。什么事，西蒙？

M：呃。。。听起来有点像电。

W：是的，没错。极光是一种电现象。正如你所知，发电机有两个组成部分：导体和磁场。为了发电，导体必须穿过磁场才能产生力。极光的导体是携带带电粒子流的太阳风。

M：所以，当带电粒子到达地球磁场时，它们会在磁场中向南北磁极移动。

W：没错。然后粒子与大气中的气体发生碰撞，氧和氮原子被激发。然后，当粒子失去激发并恢复到正常状态时，它们以光的形式释放能量，发出极光。氧气释放出暗红色或幽灵般的绿色。氮气会发出玫瑰红色或洋红。极光的活动随太阳的活动而变化。当太阳静止时，极光只能在一个小范围内看到。然而，当太阳活动时，可以在加拿大南部和美国北部看到北极光。

三、The Cause of Auroras托福红Delta听力问题：

Q1:1.What aspect of the auroras does the professor mainly discuss?

A.Myths about the auroras

B.How to videotape the auroras

C.What causes the auroras 

D.The beauty of the auroras

Q2:What colors are commonly seen in the auroras?Click on two answers.

A.Orange

B.Red

C.Green

D.Brown

Q3:Why does the professor say this:

A.To compare the views from the North and South Poles

B.To explain why extremes of daylight exist at the poles

C.To point out where the auroras are most visible

D.To suggest taking a trip to the North or South Pole

Q4:Why does the professor say this:

A.To explain how the auroras are electrical in nature

B.To change the subject to something more interesting

C.To encourage the student to observe the auroras

D.To imply that the auroras contribute to global warming

Q5:The professor briefly explains how the auroras are formed.Indicate whether each sentence below is a part of the process.

For each sentence,click in the correct box.

Q6:What can be inferred about the auroras?

A.The auroras change in size and shape during the night.

B.The color of auroras is related to the type of gas involved.

C.The beauty of auroras is difficult to measure accurately.

D.The auroras are a possible source of nuclear energy.

四、The Cause of Auroras托福红Delta听力答案：

A1:正确答案：C

A2:正确答案：BC

A3:正确答案：C

A4:正确答案：A

A5:正确答案：ABAA

A6:正确答案：B

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