北极光 英文介绍 北极光是怎么形成的

北极光 英文介绍

不是上面的翻译。 是介绍 北极光（Aurora Borealis）的英文短文： 极光： Auroras (North/South Polar Lights) are natural colored light displays in the sky, usually observed at night, particularly in the polar zone. They typically occur in the ionosphere. Some scientists[who?] call them "polar auroras". In northern latitudes, the effect is known as the aurora borealis, named after the Roman goddess of 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 was rising from an unusual direction. The aurora borealis is also called the northern polar 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. The Cree call this phenomenon the Dance of the Spirits. Its southern counterpart, the aurora australis/southern polar lights, has similar properties. Australis is the Latin word for "of the South". Benjamin Franklin first brought attention to the "mystery of the Northern Lights." He theorized the shifting lights to a concentration of electrical charges in the polar regions intensified by the snow and other moisture. )

北极光是怎么形成的

1)由于从太阳射来的电子接近地磁场之偏转，及绕磁极集中成螺旋状所引起之辐合效应。为通过极稀薄而最冷之高气层之放电，造成大气中的瑰丽发光现象。形状有拱弧，长条与薄雾等，所呈状态从跳动，闪烁到爆炸都有。极光颜色通常是白中带绿，带红，带黄，带蓝，带紫或粉红，持续时间从数小时至数日不等
(2)为什么极光只出现于地球两极地区？原来地球有着强大的磁场，来自太阳的带电粒子受到地球磁场的影响，由于磁力线辐合的效应，这些电子与正离子所构成的气体(我们称他为电浆)会在沿地球磁场线方向产生一个向上的电场，于是电浆中的电子就被此电场加速，打入高纬度之电离层，所以只有射向两极地区的带电粒子才能进入高层大气产生极光。
(3)地磁北极在加拿大(地磁北极距地理北极约1200km之远。两者以地心相交约11.5o。)，故在加拿大南部和美国北部常见到极光，西伯利亚之低磁纬度较少见到 。平时越高磁纬度地区才能看见北极光，但逢太阳风暴之激烈程度于稍低磁纬度地区也能看到。 科学家已能正确预测十一年为周期之太阳风暴，大量的从太阳风暴中的带电粒子冲向地球，与地磁场之交互作用产生绚烂景致的北极光。公元二千年正逢十一年周期高峰，于稍低磁纬度地区也能看到。。
(4)位在北极的称为北极光，位在南极的称为南极光，就如同天使头上的光环一般，套在地球南北极的夜空中。北极光与南极光有时可如同镜中影像般成对出现。