What is an aurora? - Michael Molina

翻译人员: Jing Zhou 校对人员: Qiyun Xing

Every second,

每一秒，

one million tons of matter is blasted from the Sun

一百万吨物质以一百万英里的时速

at the velocity of one million miles per hour,

从太阳射出，

and it's on a collision course with Earth!

并且还在与地球相撞的轨道上！

But don't worry,

但是不要担心，

this isn't the opening of a new Michael Bay movie.

这不是迈克尔-贝新电影的开场。

This is The Journey of the Polar Lights.

这是“极光的旅行”。

The northern and southern lights, also known as the aurora Borealis

北极光（northern light）和 南极光（southern light），也分别被称为

and aurora Australis, respectively,

北极光（aurora Borealis）和 南极光（aurora Australis），

occur when high energy particles from the Sun

产生于来自太阳的高能粒子

collide with neutral atoms in our atmosphere.

与我们大气层中性原子的相撞。

The energy emitted from this crash produces a spectacle of light

碰撞放射的能量产生了

that mankind has marveled at for centuries.

为人类赞叹数世纪的光之奇观

But the particles' journey isn't just as simple

但这些粒子的旅行不只是

as leaving the Sun and arriving at Earth.

离开太阳抵达地球那样简单。

Like any cross-country road trip, there's a big detour

就像任何一个越野自驾游，要兜很大的圈子

and nobody asks for directions.

且没有人问方向。

Let's track this intergalactic voyage

让我们来通过关注它们旅行中的三个主点

by focusing on three main points of their journey:

来跟随这星际航行：

leaving the Sun, making a pit stop in the Earth's magnetic fields,

离开太阳，在地球的磁场里歇歇脚，

and arriving at the atmosphere above our heads.

然后到达我们头顶的大气层。

The protons and electrons creating the northern lights

那些创造北极光的质子和电子

depart from the Sun's corona.

离开太阳的冕。

The corona is the outermost layer of the Sun's atmosphere

日冕是太阳大气层的最外层

and is one of the hottest regions.

也是最热的区域之一。

Its intense heat causes the Sun's hydrogen and helium atoms to vibrate

它的酷热使太阳的氢和氦原子振动

and shake off protons and electrons

并甩掉质子和电子

as if they were stripping off layers on a hot, sunny day.

好像它们在晴朗炎热的日子里脱掉层层的衣服。

Impatient and finally behind the wheel,

即不耐烦又终于掌起了舵，

these free protons and electrons move too fast

这些自由质子和电子移动地太快

to be contained by the Sun's gravity

以至于不受太阳的重力控制

and group together as plasma, an electrically charged gas.

并且聚在一起形成等离子体， 即一种带电的气体。

They travel away from the Sun as a constant gale of plasma,

它们以不变的等离子风的形式离开太阳，

known as the solar wind.

被称为太阳风。

However, the Earth prevents the solar wind from traveling straight into the planet

然而，地球用一段迂回，即磁层

by setting up a detour, the magnetosphere.

来阻止太阳风直接进入地球。

The magnetosphere is formed by the Earth's magnetic currents

磁层由地球的磁流形成

and shields our planet from the solar winds

并且通过在地球周围散发粒子

by sending out the particles around the Earth.

来保护地球免遭太阳风。

Their opportunity to continue the journey down to the atmosphere

它们继续向下去往大气层的旅程的机会

comes when the magnetosphere is overwhelmed by a new wave of travelers.

在磁层被新一波旅行者制伏之际来临。

This event is coronal mass ejection,

这被称为日冕物质抛射，

and it occurs when the Sun shoots out

在太阳往太阳风里发射

a massive ball of plasma into the solar wind.

一大团等离子体时发生。

When one of these coronal mass ejections collides with Earth,

当其中一个日冕物质抛射与地球相撞时，

it overpowers the magnetosphere and creates a magnetic storm.

它制伏磁层并产生磁暴。

The heavy storm stresses the magnetosphere until it suddenly snaps back,

这大磁暴施压于磁层直到它突然回弹，

like and overstretched elastic band,

就像伸展过度的橡皮筋，

flinging some of the detoured particles towards Earth.

把一些已经绕开的粒子抛向地球。

The retracting band of the magnetic field drags them down to the aurora ovals,

那回缩的磁场橡皮圈把它们向下拽到

which are the locations of the northern and southern lights.

南北极光所在的极光椭圆区。

After traveling 93 million miles across the galaxy,

在走过穿越银河系的九千三百万英里以后，

the Sun's particles finally produce their dazzling light show

这些太阳的粒子终于在一些朋友的帮助下

with the help of some friends.

上演了它们炫目的光影表演。

20 to 200 miles above the surface,

在地表上空的二十到两百英里处，

the electrons and protons meet up with oxygen and nitrogen atoms,

那些电子和质子与氢和氮原子相遇，

and they sure are happy to see each other.

它们当然很高兴见到彼此。

The Sun's particles high five the atoms, giving their energy

这些太阳粒子与那些原子击掌，把它们的能量传递给

to the Earth's neutral oxygen and nitrogen atoms.

地球的中性的氢与氮原子。

When the atoms in the atmosphere are contacted by the particles,

当大气层里的原子被那些粒子碰触后，

they get excited and emit photons.

它们激动起来并发射光子。

Photons are small bursts of energy in the form of light.

光子是能量以光的形式的小爆发。

The colors that appear in the sky

天空中出现的那些颜色

depend on the wavelength of the atom's photon.

由那些原子的光子的波长决定。

Excited oxygen atoms are responsible for the green and red colors,

兴奋的氢原子掌管绿色和红色，

whereas excited nitrogen atoms produce blue and deep red hues.

而激动的氮原子制造出蓝色和深红色。

The collection of these interactions

这些互动的集合

is what creates the northern and southern lights.

就是极光的创造者。

The polar lights are best seen on clear nights

南北极附近的区域的晴朗夜晚

in regions close to magnetic north and south poles.

是观测极光的最佳时机。

Nighttime is ideal

夜晚之所以理想

because the Aurora is much dimmer than sunlight

是因为极光比阳光暗很多，

and cannot be seen in daytime.

在白天是看不到的。

Remember to look up at the sky and read up on the Sun's energy patterns,

记得仰望天空并仔细研究太阳的能量模式，

specifically sunspots and solar flares,

特别是太阳黑子和太阳耀斑，

as these will be good guides for predicting the auroras.

因为这些将是预测极光的好向导。