土星的环和季节
(原标题: Rings and Seasons of Saturn)
2021-09-19
浏览次数: 30
在土星上，光环告诉你季节。在地球上，星期三标志着春分，也就是地球赤道直接向太阳倾斜的时候。由于土星的大环沿着行星的赤道轨道运行，当土星的自转轴指向太阳时，这些环从太阳的方向来看是最突出的。相反，当土星的自转轴指向侧面时，就会出现春分，而且不仅从太阳上，从地球上也很难看到边缘上的环。在这幅特色的蒙太奇中，2004年至2015年间的土星图像被叠加在一起，以显示这颗巨大的行星从南方的夏天向北方的夏天移动。上个月，土星离地球最近了，这个月，这个带光环的巨人在夜晚的大部分时间里仍然明亮可见
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On Saturn, the rings tell you the season. On Earth, Wednesday marks an equinox, the time when the Earth's equator tilts directly toward the Sun. Since Saturn's grand rings orbit along the planet's equator, these rings appear most prominent -- from the direction of the Sun -- when the spin axis of Saturn points toward the Sun. Conversely, when Saturn's spin axis points to the side, an equinox occurs and the edge-on rings are hard to see from not only the Sun -- but Earth. In the featured montage, images of Saturn between the years of 2004 and 2015 have been superposed to show the giant planet passing from southern summer toward northern summer. Saturn was as close as it can get to planet Earth last month, and this month the ringed giant is still bright and visible throughout much of the night
© Damian Peach