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!
太陽(yáng)是暴躁的,有它自己的一種氣象。這是那么熱列和活躍,甚至太陽(yáng)的引力無(wú)法控制它自己的的大氣層!能源從太陽(yáng)向地球以帶電粒子流的形式流逝,以大約一百萬(wàn)英里每小時(shí)的速度移動(dòng)。這些粒子被稱為等離子,來(lái)自太陽(yáng)的等離子流叫做太陽(yáng)風(fēng)。太陽(yáng)越活躍,太陽(yáng)風(fēng)越強(qiáng)。
太陽(yáng)風(fēng)不斷流向地球,但不用擔(dān)心,因?yàn)槲覀兊男乔蛑車写艌?chǎng)保護(hù)著。相同的磁場(chǎng),即使你的指南針指向北方也會(huì)轉(zhuǎn)向來(lái)自太陽(yáng)的粒子的南北兩極。帶電粒子變成為被困在地球周圍的磁帶。當(dāng)大量的太陽(yáng)風(fēng)在地球磁場(chǎng)爆炸,首先磁場(chǎng)收到擠壓,接著磁場(chǎng)磁力線斷開(kāi)又閉合。
磁場(chǎng)磁力的線斷開(kāi)又閉合可能會(huì)導(dǎo)致被困在安全帶里的稱為電子的原子粒子下降的進(jìn)入地球大氣層的在兩極。由于電子落到地球,他們與大氣中的氣體分子發(fā)生碰撞的,產(chǎn)生的光線在天空中閃爍。每種大氣氣體發(fā)光的顏色不同。氧氣和氮?dú)獬始t色和綠色,氮發(fā)紫光。由于這些不同顏色的光芒,在夜空中的舞蹈,他們組成了北極光和南極光。
看極光是有趣和令人興奮的,但通常你只能在遙遠(yuǎn)的北方阿拉斯加和加拿大這樣的地方看到他們。通常是夠慢的極光劃過(guò)天空的運(yùn)動(dòng)很容易被眼睛地看到,但他們也可以跳動(dòng),閃爍,甚至像波浪一樣移動(dòng)。太陽(yáng)活動(dòng)高峰期間,極光在南至佛羅里達(dá)州,甚至墨西哥也可以被看見(jiàn)!
極光似乎往往是非常接近地面,但最低極光仍然高于地面約100公里,距離遠(yuǎn)高于云層的或飛機(jī)的飛行高度。一個(gè)典型極光帶可以數(shù)千公里長(zhǎng),高幾百公里,但只有幾百米厚。
我們希望您能在你的一生中至少一次前往北極圈以北地方看到北極光。我們知道你將永遠(yuǎn)不會(huì)忘記!
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