oscar 2009-3-21 10:06
美國．科羅拉多州上空的流星
Comet Dust over Colorado
[img]http://i16.tinypic.com/403wxnq.jpg[/img]
影像版權與提供: Thad V'Soske
[color=navy]Explanation: [/color]
The rock formation in the foreground of this night view was recorded on August 10, illuminated by light from a waning gibbous Moon. Even though the sky above also scatters the bright moonlight, a brilliant meteor was captured as it flashed across the scene during the 30 second long exposure. Of course, the meteor was part of the annual rain of dust from periodic Comet Swift-Tuttle known as the Perseid Meteor Shower. Leaving trails that point back to a radiant in the constellation Perseus, the ancient dust particles are vaporized as they enter the atmosphere at about 60 kilometers per second, their visible streaks beginning at altitudes of around 100 kilometers. And though it looks like the knuckles of a giant hand, the curious rock formation can be found in Colorado National Monument park, USA, planet Earth.
[color=navy]說明: [/color]
這幅夜間影像前景的岩石，在8月10日拍攝時是被農曆17日的月光所照亮。雖然上方的天空也被散射的明亮月光所照亮，但這幅曝光時間為30秒的影像，還是能捕捉到一顆掠過視野的明亮流星。這顆流星是每年定期出現的英仙座流星雨之成員，其源頭則是從史威福-塔托彗星剝落的塵埃碎片。這群流星所留下的流星跡，其指向可回溯出位在英仙座內的央源。這些遠古塵埃以每秒60公里的高速進入地球大氣，在瞬間就會被汽化，所產生的流星跡起點的標高大約為100公里。這座外觀很像巨人手掌指關節的巨岩，位在地球上的美國．科羅拉多國家紀念公園內。
[size=2]資料來源: Scientific American
Department of Physics, NCKU
Cosmotions[/size]