Copyright:Christopher Go
中文翻譯:
在太空的深處，我們能看到土星的美麗光環和兩顆小小的冰月：Dione和Rhea。這幅驚人的圖片是在11月20日拍攝的，當時的土星光環幾乎跟地球的視線平行。每13到16年，從地球看土星的時候，光環的排列會剛好形成一個特殊的角度，我們就能夠看到光環似乎消失的奇妙情景。再過幾天，也就是11月23日，土星的光環會變得最窄，然後會再次變寬。Dione和Rhea這兩顆小月亮，分別需要2.7天和4.5天才會繞土星轉一圈。而下次從地球看到土星光環的特殊排列則要等到2038年！
原文:
Seen to the left of Saturn’s banded planetary disk, small icy moons Dione and Rhea are caught passing in front of the gas giant’s extensive ring system in this sharp telescopic snapshot. The remarkable image was recorded on November 20, when Saturn’s rings were nearly edge-on when viewed from planet Earth. In fact, every 13 to 16 years the view from planet Earth aligns with Saturn’s ring plane to produce a series of ring plane crossings. During a ring plane crossing, the interplanetary edge-on perspective makes the thin but otherwise bright rings seem to disappear. By November 23rd Saturn’s rings will have reached a minimum angle for now, at their narrowest for viewing from planet Earth, but then start to widen again. Of course, Dione and Rhea orbit Saturn near the ring plane once every 2.7 and 4.5 days respectively, while the next series of Saturn ring plane crossings as seen from Earth will begin again in 2038.
來源:NASA每日圖片
