Are the Northern Lights dangerous? - Fabio Pacucci

翻译人员: Siyu Lian 校对人员: Yip Yan Yeung

On September 1st, 1859, miners following the Colorado gold rush woke up

1859 年 9 月 1 号,

追随科罗拉多淘金热潮的矿工们 在又一个晴天里醒来，

to another sunny day.

Or so they thought.

至少他们以为如此。

To their surprise, they soon discovered it was actually 1 am;

没过多久，他们惊讶地发现 现在实际上是凌晨一点；

and the sky wasn’t lit by the Sun, but rather by brilliant drapes of light.

天空并不是被太阳， 而是被绚丽的光幕点亮的。

The blazing glow could be seen as far as the Caribbean,

远在加勒比海的人都能 看到这片炽热的光芒，

leading people in many regions to believe that nearby cities had caught fire.

导致许多地区的人都认为 临近的城市着火了。

But the true cause of what would come to be known as the Carrington Event

这背后真正的起因是 有史以来最大的一次太阳风暴，

was a solar storm— the largest in recorded history.

后来被称为“卡灵顿事件” （Carrington Event）。

Solar storms are one of many astrophysical phenomena caused by magnetic fields.

太阳风暴是许多由磁场 导致的天体物理现象之一。

These fields are generated by movements of electrically charged particles

磁场是由带电粒子的运动所产生的，

like protons and electrons.

比如质子和电子。

For example, Earth’s magnetic field is generated by charged molten metals

举个例子，地球的磁场是由在外核 循环的带电熔化金属所产生的。

circulating in the planet's outer core.

Similarly, the Sun’s magnetic field is generated by large convective movements

太阳的磁场同样是在 组成恒星的等离子体中

in the plasma that composes the star.

大型对流运动所产生的。

As this plasma slowly swirls,

在等离子体缓慢的旋转中，

it creates areas of intense magnetic activity called sunspots.

它创造出了一块被称为太阳 黑子的强烈磁活动区域。

The magnetic fields that form near these regions

在这周围产生的磁场 常常变得扭曲和紧绷。

often become twisted and strained.

And when they’re stretched too far, they snap into simpler configurations,

当这些磁场过度地伸展， 它们就会分裂成简单的结构，

releasing energy that launches plasma from the Sun’s surface.

并且在太阳表面释放出能量， 发射等离子体。

These explosions are known as coronal mass ejections.

这些爆炸被称为日冕物质抛射 （coronal mass ejection）。

The plasma— mostly made of protons and electrons— accelerates rapidly,

由多数质子和电子 构成的等离子体迅速加速，

quickly reaching thousands of kilometers per second.

很快达到了每秒 数千米的速度。

A typical coronal mass ejection covers the distance between the Sun and the Earth

一个典型的日冕物质抛射可以 在几天之内从太阳到达地球，

in just a couple of days,

flowing along the magnetic field that permeates the solar system.

沿着散布在太阳系的磁场流动。

And those that cross the Earth’s path are drawn to its magnetic field lines,

经过地球路径的日冕物质抛射 会被地球的磁场线吸引，

falling into the atmosphere around the planet’s magnetic poles.

在地球的磁极的附近 落入大气层中。

This tidal wave of high-energy particles excites atmospheric atoms

这些高能粒子浪潮刺激了 大气层中的原子，

such as oxygen and nitrogen,

比如氧原子和氮原子，

causing them to rapidly shed photons at various energy levels.

导致了它们在不同能量 水平上迅速地放射光子，

The result is a magnificent light show we know as the auroras.

形成了华丽的亮光秀， 也就是我们知道的极光。

And while this phenomenon is usually only visible near the Earth’s poles,

虽然这种现象只能在地球 两极的附近看到，

strong solar storms can bring in enough high energy particles

但是强烈的太阳风暴能带来 足够多的高能粒子，

to light up large stretches of the sky.

来点亮大片大片的天空。

The magnetic fields in our solar system are nothing

我们太阳系中的磁场和 外太空中的磁场相比

compared to those found in deep space.

来说太微不足道了。

Some neutron stars generate fields 100 billion times stronger

一些中子星产生的磁场比在太阳 黑子中发现的磁场强一千亿倍。

than those found in sunspots.

And the magnetic fields around supermassive black holes

而且，在超巨型黑洞附近的磁场

expel jets of gas that extend for thousands of light years.

释放出的气体喷流 可以延伸至数千光年。

However, on Earth, even weak solar storms can be surprisingly dangerous.

然而，在地球上，即使微弱的 太阳风暴也有惊人的危险性。

While the storms that reach us are generally harmless to humans,

虽然到达地球的风暴一般 对人来说是无害的，

the high-energy particles falling into the atmosphere

但落入大气层的高能粒子 会产生次级磁场,

create secondary magnetic fields,

which in turn generate rogue currents that short-circuit electrical equipment.

同时也会产生导致电气 设备短路的无序电流。

During the Carrington Event,

在卡灵顿事件中，

the only widespread electrical technology was the telegraph.

唯一普及的电力技术是电报。

But since then, we've only become more dependent on electrical systems.

但从那以后，人们变得 更加依赖电力系统。

In 1921, another powerful solar storm caused telephones

1921 年， 另一场强烈的太阳风暴

and telegraph equipment around the globe to combust.

导致了全球电话和 电报设备的燃烧。

In New York, the entire railway system was shut down and fires broke out

纽约的整个铁路系统都被关闭了，

in the central control building.

中央控制大楼还发生了火灾。

Comparatively weak storms in 1989 and 2003

1989 年和 2003 年的 风暴相对较弱，

turned off regions of the Canadian power grid

导致了加拿大地区电网的关闭，

and damaged multiple satellites.

并损坏了多颗卫星。

If we were hit by a storm as strong as the Carrington Event today,

如果我们今日被卡灵顿事件里 同样强度的太阳风暴击中，

it could devastate our interconnected, electrified planet.

这可能给我们这个互联、 电气化的地球带来毁灭性的伤害。

Fortunately, we're not defenseless.

幸运的是，我们不是毫无防备。

After centuries of observing sunspots,

经过多个世纪人们 对太阳黑点的观察，

researchers have learned the Sun’s usual magnetic activity

研究者发现太阳通常的磁力活动

follows an 11-year cycle,

遵循着 11 年的周期，

giving us a window into when solar storms are most likely to occur.

这给了我们预测太阳风暴 最有可能发生时段的机会。

And as our ability to forecast space weather has improved,

我们预知外太空天气的能力进步了，

so have our mitigation measures.

我们应对太阳风暴的措施 也有了进一步的发展。

Power grids can be shut off in advance of a solar storm,

电网可以在太阳风暴 到来之前关闭。

while capacitors can be installed to absorb the sudden influx of energy.

同时可以搭建电容器去 吸收突然涌入的能量。

Many modern satellites and spacecraft are equipped with special shielding

许多现代的卫星和外太空 飞船装备了特殊的屏蔽层，

to absorb the impact of a solar storm.

抵御太阳风暴带来的影响。

But even with these safeguards,

但是，就算有了这些安全措施，

it’s hard to say how our technology will fare during the next major event.

我们还是很难确定我们的技术在 下一个重大事件中会有什么表现。

It’s possible we’ll be left with only the aurora overhead

我们可能只剩下头顶上的极光

to light the path forward.

来点亮前进的方向。