The Northern Lights北极光

　　The Sun is stormy and has its own kind of weather.It is so hot and active that even the Sun’s gravity cannot hold its atmosphere in check1! Energy flows away from the Sun toward the Earth in a stream of electrified particles that move at speeds around a million miles per hour2.These particles are called plasma，and the stream of plasma3 coming from the Sun is called the solar wind.The more active the Sun，the stronger the solar wind.

　　The solar wind constantly streams toward the Earth，but don’t worry because a protective magnetic field surrounds our planet.The same magnetic field that makes your compass point north also steers the particles from the Sun to the north and south poles.The charged particles become trapped in magnetic belts around the Earth.When a large blast of solar wind crashes into the Earth’s magnetic field，the magnetic field first gets squeezed and then the magnetic field lines break and reconnect.4

　　The breaking and reconnecting of the magnetic field lines can cause atomic particles called electrons trapped in the belts to fall into the Earth’s atmosphere at the poles.As the electrons fall to the Earth，they collide with gas molecules in the atmosphere，creating flashes of light in the sky.Each atmospheric gas glows a different color.Oxygen and nitrogen glows red and green and nitrogen glows violet-purple.As these various colors glow and dance in the night sky，they create the Northern Lights and the Southern Lights.

　　Watching auroras is fun and exciting，but normally you can only see them in places far north like Alaska and Canada.The movement of the aurora across the sky is usually slow enough to easily follow with your eyes but they can also pulsate，flicker，or even move like waves.During solar maximum，5 auroras are seen as far south as Florida，even Mexico! 6

　　Auroras often seem to be very close to the ground，but the lowest aurora is still about 100 kilometers above the ground，a distance much higher than clouds are formed or airplanes can fly.A typical aurora band can be thousands of kilometers long，a few hundred kilometers high，but only a few hundred meters thick.

　　We hope you are able to travel to far north places like the Arctic Circle and see the Northern Lights at least once during your lifetime.We know you will never forget it!

　　太阳是暴躁的，有它自己的一种气象。这是那么热列和活跃，甚至太阳的引力无法控制它自己的的大气层!能源从太阳向地球以带电粒子流的形式流逝，以大约一百万英里每小时的速度移动。这些粒子被称为等离子，来自太阳的等离子流叫做太阳风。太阳越活跃，太阳风越强。

　　太阳风不断流向地球，但不用担心，因为我们的星球周围有磁场保护着。相同的磁场，即使你的指南针指向北方也会转向来自太阳的粒子的南北两极。带电粒子变成为被困在地球周围的磁带。当大量的太阳风在地球磁场爆炸，首先磁场收到挤压，接着磁场磁力线断开又闭合。

　　磁场磁力的线断开又闭合可能会导致被困在安全带里的称为电子的原子粒子下降的进入地球大气层的在两极。由于电子落到地球，他们与大气中的气体分子发生碰撞的，产生的光线在天空中闪烁。每种大气气体发光的颜色不同。氧气和氮气呈红色和绿色，氮发紫光。由于这些不同颜色的光芒，在夜空中的舞蹈，他们组成了北极光和南极光。

　　看极光是有趣和令人兴奋的，但通常你只能在遥远的北方阿拉斯加和加拿大这样的地方看到他们。通常是够慢的极光划过天空的运动很容易被眼睛地看到，但他们也可以跳动，闪烁，甚至像波浪一样移动。太阳活动高峰期间，极光在南至佛罗里达州，甚至墨西哥也可以被看见!

　　极光似乎往往是非常接近地面，但最低极光仍然高于地面约100公里，距离远高于云层的或飞机的飞行高度。一个典型极光带可以数千公里长，高几百公里，但只有几百米厚。

　　我们希望您能在你的一生中至少一次前往北极圈以北地方看到北极光。我们知道你将永远不会忘记!