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2004 March 21
A Green Flash from the Sun
Credit & Copyright: Pekka Parviainen (Polar Image)
Explanation: Many think it is just a myth. Others think it is true but its cause isn't known. Adventurers pride themselves on having seen it. It's a green flash from the Sun. The truth is the green flash does exist and its cause is well understood. Just as the setting Sun disappears completely from view, a last glimmer appears startlingly green. The effect is typically visible only from locations with a low, distant horizon, and lasts just a few seconds. A green flash is also visible for a rising Sun, but takes better timing to spot. A dramatic green flash was caught in the above photograph in 1992 from Finland. The Sun itself does not turn partly green, the effect is caused by layers of the Earth's atmosphere acting like a prism.
太阳的绿色光芒
很多人认为这只是一幕神话中的场景。另一些人认为这是一幅真实的画面，只是不知道它发生的原因。冒险家们以亲眼看到这幅景象为荣。它展现的是太阳的绿色光芒。事实上这样的绿色光芒是真实存在的而且它的原因不难理解。只不过是当太阳下山并从我们的视野中完全消失的时候，一道最后的夕阳呈现出惊奇的绿色。这种具有特点的景象仅在位置低远的地平线上可见，且仅仅持续几秒钟。绿色光芒在太阳升起的时候也可以看到，但是也需要更好的观测时间与地点。以上展现的是一道引人注目的绿色光芒的照片，该片在1992年的芬兰拍摄到的。在其中太阳自己并没有部分变绿，而是由于多层的像棱镜一般的地球大气才有了这样的效果。
[此贴子已经被作者于2004-4-5 18:07:13编辑过]
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发表于 2004-4-1 01:25:00
楼主
发表于 2004-4-21 03:44:39