A rare galaxy type, polar ring galaxies have a substantial population of stars, gas, and dust orbiting in rings nearly perpendicular to the plane of the galactic disk.

极环星系是种稀有的星系类型，它们有着几乎和银盘平面垂直，呈环形公转的大量的恒星、气体和星尘。

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Astronomers estimating the apparent age of the ring to be around 5, 000 years, also find more distant gas clouds perpendicular to the ring plane, seen here at the upper left and lower right.

天文学家推测该环的表面年龄大约在5000年左右，还发现垂直于该环形行星有着距离更远的气体云，图中就是左上和右下的部分。

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The optimum design of plane quadratic enveloping ring surface worm drive has been realized using the theory and method of optimization.

针对平面二次包络环面蜗杆传动，运用优化理论和方法，对其进行了优化设计。

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Other activities for Cassini scientists during the extended mission will include monitoring seasons on Titan and Saturn, observing unique ring events - such as the 2009 equinox when the Sun will be in the plane of the rings - and exploring new places within Saturn's magnetic "envelope" - or magnetosphere.

BBC: Nasa extends Saturn probe mission