VOA常速英语2014--美国航天局探秘范艾伦辐射带（在线收听）

NASA Probing Secrets of Van Allen Radiation Belt 美国航天局探秘范艾伦辐射带

One of the first discoveries of the space age, made in 1958, was that the Earth is surrounded with a doughnut-shaped field of highly charged particles. It was named the Van Allen radiation belt, after its discoverer, U.S. space scientist James Van Allen.  But not much was known about it until NASA launched two probes in 2012. Scientists say the data they sent back to earth is very exciting.

华盛顿— 人类进入太空时代以来的首批探索成果之一，即是1958年对于地球周围高能电磁场的发现。该磁场随后被命名为范艾伦辐射带，以纪念其发现者、美国空间科学家詹姆斯·范·艾伦。然而，在2012年美国航空航天局发射两颗专门探测器之前，人类对于此区域还知之甚少。科学家称，由探测器传回地面的数据，足以令人振奋。

Space weather can be as unpredictable as the weather on earth.  Periodic eruptions on the sun's surface eject huge clouds of highly charged protons and electrons.

宇宙气象与地面气象一样难以预测。太阳表面的周期性爆发，释放出大规模、高电荷的质子与电子。

Some of them reach the earth and cause spectacular light displays like the Aurora Borealis or Northern Lights.

其中有一些可以传送到地球，引起像北极光这样光影奇观。

When the clouds of charged particles are unusually strong, they can knock out power grids, disrupt communications and even damage electronic equipment.

当这些带电粒子异常强大之时，他们会影响电网、中断通信、甚至损坏电子设备。

But most of the time they get trapped by the earth’s magnetic field in the so-called the Van Allen radiation belt.

但大多数情况下，它们都会被地球自身的磁场所阻拦，而后者被人们称之为范艾伦辐射带。

Nevertheless, they can still inflict damage, says NASA’s program scientist, Mona Kessel.

不过，美国航空航天局的项目科学家莫娜·凯塞尔说，仍然会有一些破坏。

"We also have a lot of satellites that fly through that area - communications satellites, navigation satellites - and so we need to understand what it is that the effects are, because the effects can be quite dramatic," said Kessel.

凯塞尔说：“我们有许多卫星飞过那个区域，通讯卫星、导航卫星等。因此我们必须弄清楚影响是什么，因为这些影响可能会很大。”

To learn more about space weather, NASA in 2012 launched a pair of satellites built by Applied Physics Laboratory. Called Van Allen Probes, they were to explore the mysterious belt.  At first researchers expected only quantitative data, says project scientist Barry Mauk.

为了更好地了解宇宙气象，美国航空航天局于2012年发射了一对名为范艾伦号的探测器。探测器由应用科学实验室所研制，用以探索这片神秘区域。参与此项目的科学家巴里·莫克说，一开始他们只想得到一些定量数据。

“I was skeptical we would find anything surprising.  In fact, we found tremendous surprise. We found new structures that we never anticipated," said Mauk.

应用物理实验室项目科学家巴里·莫克说： “刚开始我对于我们是否能够有特殊发现持怀疑态度。实际上，我们后来有许多惊人的发现。我们发现了我们预料之外的结构形态。”

The Van Allen Probes discovered that, instead of two layers, the belt has an occasional third layer of charged particles and that they sometimes form zones called ‘zebra stripes’.  The probes also found how the electric and magnetic fields additionally energize the particles.

范艾伦辐号探测器发现，除去已知的两层结构，该地带还偶有第三层带电粒子存在。而它们有时会形成所谓“斑马条纹”的区域。探测器还发现了电场和磁场是如何作用于这些粒子的。

Mauk says measurements gathered by the two probes will help scientists develop computer models for creating space weather forecasts.

莫克说两个探索器所收集的数据会帮助科学家开发出电脑模型，以预测宇宙气象的变化。

“If I see something at the sun, some flare or something, and I can measure the magnetic field on the sun - there are remote ways of doing that - I can now predict how will the radiation belts respond to that," he said.

莫克说： “如果我观察到太阳的活动，比如表面爆发，我就可以测量太阳上的磁场，这是远距离的测量方法。现在我可以预测辐射带对于太阳活动的反应。”

And that, he says, may lead to sending the astronauts to their vaults or powering down the communication and navigation satellites while this effect passes by.

他说，在此基础上，在这些影响来临之时，可以让宇航员返回座舱，或者是中断通信和导航卫星等。

"And then we also just want to understand it because it's a very dynamic part of our whole space, above the earth, our electromagnetic space," said Kessel.

NASA项目科学家莫娜·凯塞尔说：“我们想了解这些是因为这是整个宇宙空间十分活跃的一部分，即在地球之上的，我们的电磁场空间。”

Scientists say better understanding of the Van Allen radiation belt will help us prepare for potential surprises from our own sun.

科学家称，对于范艾伦辐射带的更好了解有助于我们做好准备，预防太阳活动带来的潜在影响。