for billions of years, that force field has been protecting us from a beam of supercharged

想像著這力場已經保護我們幾十億年，避免讓超增壓電漿射線

plasma that otherwise wipe out life on Earth as we know it. You might think this

如我們所認知的，把地球上的生命都毀滅

is some kind of science fiction story, but it's all true. And it's what gives us this:

你可能會以為這只是段科幻故事，但這一切都是真的。而這也給了我們這個東西：

The aurora!

極光！

So the auroras are one of mankind's oldest mysteries, and we've come up with some pretty crazy theories

極光是人類最古老的傳說之一，而接下來的時間，我們已找到一些非常瘋狂的理論

of how to explain it along the way. Take Aristotle, he thought they aurora was the sky vomiting

去解釋它是如何產生的。舉亞里斯多德來說，他認為極光是天空吐出

little bits of flame! But it wasn't until the 1600's that we figured out two key things

的一點火焰！但一直到西元1600年後我們才找到兩個關鍵的東西

that helped us explain the aurora. One, Earth is really just one big magnet,

來幫助我們去解釋極光。第一，地球真的只是個巨大的磁鐵

and second, it turns out the sun gives of a lot more than just light.

第二，原來太陽給我們的不僅僅只是光線

Long before any sunlight hits Earth, it's born at the edge of the Sun. And the edge

陽光是產生於太陽的邊緣，接著照射到地球上

of the Sun, the corona, is a busy, beautiful place, full of churning whirlpools of plasma

而太陽的邊緣，也就是日冕，是個很熱鬧又美麗的地方，充滿著攪拌中的電漿渦流

and huge magnetic arcs. All of that action is constantly releasing waves of energized

和巨大的電磁弧。這些運動會持續釋放出充滿能量的粒子波動

particles, creating what we call the "solar wind". A few days after leaving the Sun,

創造出我們所說的「太陽風」。離開太陽後的幾天內

travelling at a whopping 400 kilometers per second, that blast of charged particles reaches

以超快的每秒400公里的速度行走，這陣帶電的粒子風就會到達地球

Earth. But luckily, we've got a secret weapon on our side: Earth's swirling, molten core.

好險，我們這擁有一個祕密武器: 地球的渦旋狀，融溶狀態的地核

Our core is the key to life on Earth. It creates a magnetic

我們的地核是地球上有生命的關鍵。它在我們周圍創造了

force field around us that deflects that solar wind up and away, making life down here much

磁力場來將太陽風反射出去，使得在地面上的生命可以

more enjoyable. Then because that magnetic field we have nice things like an atmosphere and we're much less burnt-to-a-crisp

生活得更愉快。因為這個磁場，我們有個如大氣般的好東西並且由於無盡的

thanks to wave after wave of planet-sterilizing radiation. But despite all that . . . A

讓我們不會被烤焦。但儘管如此

tiiiiiny bit of that solar wind does hop on the magnetic field and rided

還是有少部分的太陽風跳出磁力場，然後往北

it up or down to the Earth's poles, and that's where we get the auroras.

或往南跑到地球的極地，也就是我們看到極光的地方

When those energized particles smash into gases wayyyyy up high in our atmosphere, they

當那些能量粒子在極高空中將大氣中的氣體擊碎

"excite" them, which means the gas atoms grab on to a bit of energy. But they don't

會「刺激」它們，意思是氣體原子會獲得一點能量

stay excited for long. They give off that stored energy in a bright burst of

但不會維持很久。它們會以一道如爆裂般的亮光釋放出儲存的能量

light. Different atoms in our atmosphere each give off different colors.

大氣中不同的原子會釋放出不同顏色

Excited oxygen would give off that familiar green and red that most of us think of when

受刺激的氧氣會釋放出我們熟悉的綠色和紅色，這也是當我們聽到「極光」時

we hear "aurora". But there's also nitrogen up there, and it can give off a really cool

會想到的顏色。但大氣中還有氮氣，而它們可釋放出很酷的

mix of red and blue light that makes the sky glow this incredible purplish-pink. Now, we

紅藍混合色，使得天空發出這不可思議的略帶紫色的粉紅色

can only see this happening at night, but it's happening 24 hours a day, every day of every year! It's

現在我們只能在夜間看到極光，但它其實年年月月，每天24小時都存在著！

also happening on Saturn and Jupiter.

土星和木星上也有極光這現象

Sometimes the Sun takes that wind and turns up to eleven, and that can be a very dangerous sight

有時，太陽風會在正午十一點時增大，而去直視此景可是件非常危險的事

to behold. Extreme solar storms called coronal mass ejections can erupt into space almost

強烈的太陽風暴稱為日冕物質拋射，會幾乎無預警的噴射到宇宙中

without warning, unleashing huge waves of charged particles. If they happen to be pointed

進而釋放大量帶有能量粒子的波動。假如它們往地球跑來

at Earth, then . . . look out.

那麼...得小心一點

These storms are incredibly powerful. Astronauts that are working outside of the Earth's magnetic field

這個風暴是無可想像的強大。在地球磁力場外運行的太空人說

say that if you close your eyes during one of these solar storms, you see bright

即使你在這太陽風暴中閉上眼，你還是能夠看見

flashes of light when the charged particles reacting with the fluid inside your eye. In 1859, a storm

很亮的閃光，因這些能量粒子會跟你眼中的液體產生反應

so powerful hit Earth that it powered a telegram from Boston to Portland, Maine

1859年，有一個風暴因能量太大，衝擊地球時啟動了一座在波士頓的電報機發送至緬因州的波特蘭

. . . with the equipment unplugged.

...而這時這設備是沒插插頭的

But, when those rare violent storms hit Earth's magnetic field and ride up to the

但，當那些偶爾發生的猛烈的風暴撞擊到磁場後跑到

polar atmosphere, we are treated to an aurora show like no other. Now these images are more than just

極圈的大氣中，就如同款待我們看一場絕無僅有的極光秀。這些影像

works of art, they give scientists to study how solar storms affect life here on

不僅是件藝術，它們也讓科學家有辦法去研究太陽風暴會對地球上的生命有甚麼影響

Earth, like our electronics and communications. Some of the best views of Earth's auroras

例如我們的電子和通訊。捕捉地球上的極光最好的位置

have been captured from the International Space Station, the Space Station passes near the north

就是國際太空站，它每90分鐘就會經過

and south poles of our planet about once every 90 minutes. So if they pass by the poles while

我們星球的南北極點。所以，假如它經過極點時正好是夜間呢？

it's dark? The auroras are close enough to touch! Although I wouldn't recommend that.

那麼極光就近得好像可以摸得到一般！雖然我不推薦這樣

NASA makes sure that the astronauts that work on the ISS are highly trained photographers.

美國太空總署會確定在國際太空站工作的太空人都是訓練有素的攝影師

And artists down here on Earth are taking their photos and remixing them into creations

然後地球上的藝術家則會將他們的照片後製成足以讓你

that are enough blow your mind.

大開眼界的創作品

This celestial light show has been burning bright for perhaps billions of years, and

這天空的燈光秀已閃閃發光也許有數十億年了

it's more than just Earth's private art show. It's painted by this invisible

而這不僅只是地球本身的藝術展出。它是由圍繞在我們生活的星球上

force surrounding our living planet, a force that catches wind from the Sun, and turns

看不到的力量所繪製出的，這力量獲取從太陽來的風，然後

it into light. It gives humans a constant reminder of the beauty of the night sky, and

將其轉成光線。它提供了我們美麗的夜空的永恆記憶

it's right in our planetary backyard. And that's pretty awesome.

而這就在我們星球的後院。並且非常的令人嘆為觀止