從國際太空站看極光 |《國家地理》雜誌
https://youtu.be/l3QXsVlTB2U
#美國太空總署（#NASA） 的太空人傑克．費雪（Jack Fisher）與我們分享了這段美麗的縮時影片。#極光 現象主要發生在地球的磁極附近（南極或北極）。當太陽風中的帶電粒子與大氣中的原子或分子碰撞時就會發光。
極光的成因 What Causes The Northern Lights? | BrainStuff - HowStuffWorks
There are many misconceptions about what causes the Aurora Borealis when it really requires solar winds, magnetic fields and excited atmospheric gases.
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The Northern Lights are beautiful and odd and have understandably inspired many myths. The Vikings thought they were a bridge between our world and Asgard where Thor and the other gods live. In another Norse myth, they are the light reflected of the armor of the Valkyries. And people in Finland thought it was the archangel Michael (John Travolta) battling Beelzebub (the devil).
Wrong. Wrong. Wrong. All wrong.
It was the famous early astronomer and recanter of science, Galileo Galilei, who gave the Northern lights the name Aurora Borealis, which means “dawn of the North” in Latin. But it wasn’t until Norwegian scientist Christian Birkeland figured it out in 1896 that the true origin of the auroras was understood.
In the center of the Earth, the molten iron core generates magnetic fields that extend through the crust and into space around the planet, creating what’s called Earth’s magnetosphere. It’s a pretty great thing that Earth has it, because the magnetosphere protects us from all manner of charged particles spit out from the Sun.
The Sun is so hot that it produces plasma (a fourth state of matter) where positively charged atoms (ions) and negatively charge electrons flow freely around one another. These highly charged particles have enough energy to escape the Sun’s gravity and fly out into space, barreling toward Earth at 1 million miles per hour like a shotgun blast of solar hate. This is called solar wind.
When they encounter our magnetosphere, most of these ions and electrons bounce harmlessly off and Earth is saved. But some of these particles make it through the magnetosphere where it’s weakest (at the north and south poles), and when they do the light show begins.
The electrons that make it into our atmosphere interact with some of the elements there, particularly oxygen and nitrogen. The electrons transfer energy to them, exciting them in the process. To calm down, the excited atoms must release some energy, which they do as tiny packets of light called photons -- beautiful, beautiful photons.
Depending on where in the atmosphere the electrons interact with these other atoms, different colors are produced. Oxygen emits a yellow-green color up to about 150 miles in the atmosphere. After that, it turns red. Nitrogen emits a nice blue color about 60 miles up. And don’t forget these colors can blend, which can create glowing pinks, purples and whites. It’s like Miami Beach up there.
This interplay is most vibrant during solar storms, which depend somewhat on the Sun’s solar cycle. And, although these lights can be produced at all hours, they aren’t visible during the day, since the sunlight outshines them.
這段影片對極光形成的解說深入淺出、非常精彩，舞菇轉貼了影片的逐字稿在影片下方，有興趣的人可以轉貼到線上翻譯軟體了解。
Aurora Borealis Explained | truemaskedwabbit
這段影片詳盡的詮釋了太陽風暴的形成、依序穿越太陽系行星來到地球、以及地球磁場對應太陽風暴的保護機制，沒有逐字稿，可以開啟youtube的字幕和自動翻譯輔助閱讀
【極光冷知識✨】# 冷知識 | 晴天旅遊
這段影片深入淺出很用心，小朋友也很容易理解唷^^ (給100個讚)
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