我想要北極光的介紹而及產生原因～ｔｈａｎｋ

極光（Polar aurora）出現於地球的高磁緯地區上空。是一種絢麗多彩的發光現象。由來自地球磁層或太陽的高能帶電粒子流（太陽風）使高層大氣分子或原子激發(或電離)而產生。另外，在太陽黑子多的時候，極光出現的頻率也大。
極光是地球周圍的一種大規模放電的過程。來自太陽的帶電粒子到達地球附近，地球磁場迫使其中一部分沿著磁場線集中到南北兩極。當他們進入極地的高層大氣時，與大氣中的原子和分子碰撞並激發，產生光芒，形成極光。
極光不只在地球上出現，太陽系內的其他一些具有磁場的行星上也有極光。
在北半球觀察到的極光稱北極光，南半球觀察到的極光稱南極光。也有科學家發現火星、木星上的極光。
http://zh.wikipedia.org/w/index.php?title=%E6%9E%81%E5%85%89&variant=zh-hant
Auroras (or aurorae) [snglr.: aurora] are natural different colored light displays, which are usually observed in the night sky, particularly in the polar zone. Some scientists therefore call them "polar auroras" (or "aurorae polaris"). In northern latitudes, it is known as the aurora borealis, named after the Roman goddess of the dawn, Aurora, and the Greek name for north wind, Boreas. It often appears as a greenish glow (or sometimes a faint red), as if the sun were rising from an unusual direction. The aurora borealis is also called the northern lights, as it is only visible in the North sky from the Northern Hemisphere. The aurora borealis most often occurs from September to October and from March to April.
Its southern counterpart, aurora australis, has similar properties. Australis is the Latin word for "of the South".
http://en.wikipedia.org/wiki/Aurora_(astronomy)

極光（Polar aurora）出現於地球的高磁緯地區上空。是一種絢麗多彩的發光現象。由來自地球磁層或太陽的高能帶電粒子流（太陽風）使高層大氣分子或原子激發(或電離)而產生。另外，在太陽黑子多的時候，極光出現的頻率也大。
極光是地球周圍的一種大規模放電的過程。來自太陽的帶電粒子到達地球附近，地球磁場迫使其中一部分沿著磁場線集中到南北兩極。當他們進入極地的高層大氣時，與大氣中的原子和分子碰撞並激發，產生光芒，形成極光。
極光不只在地球上出現，太陽系內的其他一些具有磁場的行星上也有極光。
在北半球觀察到的極光稱北極光，南半球觀察到的極光稱南極光。也有科學家發現火星、木星上的極光。
極光按形態可分為：

勻光弧極光
射線式光柱極光
射線式光弧光帶極光
簾幕狀極光
極光冕
按觀測的電磁波波段分為：

光學極光
無線電極光
按激發粒子類型可分為：

電子極光
質子極光
按發生區域可分為：

極光帶極光
極蓋極光
中緯極光紅弧

圖片參考：http://upload.wikimedia.org/wikipedia/commons/thumb/a/aa/Polarlicht_2.jpg/250px-Polarlicht_2.jpg


圖片參考：http://upload.wikimedia.org/wikipedia/commons/thumb/2/23/Auroraborealissm.jpg/250px-Auroraborealissm.jpg

"Aurora Borealis" redirects here. For other uses, see Aurora Borealis (disambiguation).
For other uses, see Aurora (disambiguation).
Auroras (or aurorae) [snglr.: aurora] are natural different colored light displays, which are usually observed in the night sky, particularly in the polar zone. Some scientists therefore call them "polar auroras" (or "aurorae polaris"). In northern latitudes, it is known as the aurora borealis, named after the Roman goddess of the dawn, Aurora, and the Greek name for north wind, Boreas. It often appears as a greenish glow (or sometimes a faint red), as if the sun were rising from an unusual direction. The aurora borealis is also called the northern lights, as it is only visible in the North sky from the Northern Hemisphere. The aurora borealis most often occurs from September to October and from March to April.
Its southern counterpart, aurora australis, has similar properties. Australis is the Latin word for "of the South".

圖片參考：http://upload.wikimedia.org/wikipedia/en/thumb/1/1d/Red_and_green_aurora.jpg/250px-Red_and_green_aurora.jpg


圖片參考：http://upload.wikimedia.org/wikipedia/commons/thumb/f/f7/Aurora_Borelis_22Jan2004.jpg/250px-Aurora_Borelis_22Jan2004.jpg

極光到底是甚麼？
極光是地球大氣高層的氣體分子或原子受來自太陽的高能電子碰撞後發射的。簡單來說，分子或原子受電子碰撞後，會被激發至較高的能態，甚至被電離。當離子重新俘獲電子，輾轉回到基態的時候，便會被發射某些擁有特定波長的光波。

來自太陽的紫外線把氧分子分解成原子，成為了大氣最高層 (電離層) 的主要成份。當氧原子受電子激發後，便會發出極光那主要的淺綠色光芒。能量較高的電子則可深入大氣層較低的地方，激發那裡的中性氮分子，發出粉紅色或紫紅色的光輝。電離的氮分子則發出紫藍色的光。這些次要的激發豐富了極光的顏色，為這道美麗的卷簾添上了悅目的花邊。

What is aurora?
Aurora is the highest level of the Earth's atmospheric gas molecules or atoms from the sun by the high-energy electron impact after the launch. In simple terms, the atomic or molecular electronic after the impact, will be excited to a higher energy state, even ionization. When electronic ion re-capture their way, the return to the ground state, will be launching some specific wavelength of light waves have.

Ultraviolet rays from the sun decomposed into atomic oxygen molecules into the atmosphere at the highest level (the ionosphere) the main ingredients. After oxygen atom electronic excitation, will then send out the aurora that main greenishness ray. Higher energy electron can be in-depth local lower atmosphere, where the excited neutral nitrogen molecules, a pink or purple brilliance. Ionized nitrogen molecules issued purple and blue light. This secondary excitation enriched the aurora color, for this beautiful shutter Road add a decent and the lace.

由於從太陽射來的電子接近地磁場之偏轉，及繞磁極集中成螺旋狀所引起之輻合效應。為通過極稀薄而最冷之高氣層之放電，造成大氣中的瑰麗發光現象。形狀 有拱弧，長條與薄霧等，所呈狀態從跳動，閃爍到爆炸都有。
Because shoots from the sun defluxion of the electronic close earth magnetic field, and circles the magnetic pole to concentrate spiral-shaped causes the spoke to gather the effect. For electric discharge of through extremely thin, but the coldest high aerosphere, creates in atmospheric the magnificent photoluminescence. The shape has the arch arc, the sliver with the mist and so on, assumes the condition from the beat, glitters has to the detonation.