Astronomy Picture of the Day

Explanation: NASA's robot spacecraft Voyager 2 made this image of Saturn as it began to explore the Saturn system in 1981. Saturn's famous rings are visible along with two of its moons, Rhea and Dione which appear as faint dots on the right and lower right part of the picture. Astronomers believe that Saturn's moons play a fundamental role in sculpting its elaborate ring system. A robot spacecraft named Cassini was launched last October and is expected to rendezvous with the giant gas planet in 2004.

美國航太總署的無人駕駛太空船"旅行家2號"，於1981年開始探索土星系統時，拍下了這張土星的影像。 在這幅影像裡，土星著名的環系及兩顆衛星土衛五和土衛四，隱約出現在視野的右側及右下方。 天文學家相信土星的衛星在塑造它複雜的環系中，扮演著奠基的角色。 一艘名為卡西尼號的無人太空船於去年十月發射，預計將在2004年抵達並開始繞行這顆龐大的氣態行星。