意大利天空的五星联珠

2021年12月19日

Planetary Alignment over Italy
Image Credit & Copyright: Antonio Finazzi

Explanation: It is not a coincidence that planets line up. That’s because all of the planets orbit the Sun in (nearly) a single sheet called the plane of the ecliptic. When viewed from inside that plane — as Earth dwellers are likely to do — the planets all appear confined to a single band. It is a coincidence, though, when three of the brightest planets all appear in nearly the same direction. Such a coincidence was captured earlier this month. Featured above (right to left), Venus, Saturn, and Jupiter were all imaged together in a line just after sunset, from the San Fermo Hills, Bergamo, Italy. Joining the alignment are Earth’s Moon, and the position of the more distant Uranus. Bands of clouds streak across the sky toward the setting Sun. As Comet Leonard fades, this planetary alignment — absent the Moon — should persist for the rest of the month.

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Tomorrow’s picture: comet fireball

意大利天空的五星联珠
影像提供与版权: Antonio Finazzi

说明: 行星会聚有如联珠并非偶然。这是因为所有行星绕行太阳的轨道，几乎都在黄道上。所以从黄道面上看出去，就如地球住民经常所为，这些行星看起来都位在同一平面上。不过，如果最明亮的行星之三几乎都在同一方向，形同联珠，那这就是纯属巧合了。这个月在意大利基乌杜诺镇拍下的这幅主题影像，就记录了这种巧合。在当时刚日落后的视野里，从右到左金星、土星、和木星连成一线。而参与这场行星联珠聚会的，还有月亮和更遥远的天王星。此外，影像里还可见到指向落日的带状云彩。在这个月里，李奥纳德彗星会逐渐变暗，但仍然可以见到除了月亮之外的这些明亮行星。

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明日的图片: comet fireball