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2012.7.3『土星环的阴影』#APOD同步#

人类制造的智能探测器又一次捕捉到了土星震撼人心的美景——包括一个明亮的卫星，极细的行星环，怪异的断续风暴和弯曲变形的阴影，不用说，这自然是来自卡西尼探测器。泰坦——土星最大的卫星——在图中显现出平滑无光的褐色，这是由于它被厚重的云层包围。图中的土星环看上去像一条极细的直线，因为它极平又出现在一个和观测点平行的角度。因此土星环的细节唯有在它投射在巨大土星的云层上的阴影中可见。又因为土星环和泰坦的轨道在一个平面上，它们看似直穿过泰坦。在土星的上层大气中，云层显现出很多细节，包括绵长的云带中的暗点，暗示着高海拔的湍流。对于泰坦环绕土星运行时的扭曲度的最新的精确测量暗示着此卫星地下极其有可能存在大量的海水。

Humanity's robot orbiting Saturn has recorded yet another amazing view. That robot, of course, is the spacecraft Cassini, while the new amazing view includes a bright moon, thin rings, oddly broken clouds, and warped shadows. Titan, Saturn's largest moon, appears above as a featureless tan as it is continually shrouded in thick clouds. The rings of Saturn are seen as a thin line because they are so flat and imaged nearly edge on. Details of Saturn's rings are therefore best visible in the dark ring shadowsseen across the giant planet's cloud tops. Since the ring particles orbit in the same plane as Titan, they appear to skewer the foreground moon. In the upper hemisphere of Saturn, the clouds show many details, including dips in long bright bands indicating disturbances in a high altitude jet stream. Recent precise measurements of how much Titan flexes as it orbits Saturn hint that vast oceans of water might exist deep underground.