黑夜的阴影
(原标题: Shades of Night)
2024-02-28
浏览次数: 24
夜晚的天空是如何变黑的？分阶段，以不同的特色颜色从地平线升起。这张特色图片从左到右，在20个不同的垂直波段显示了日落后越来越晚的黄昏时间。这张照片是上个月在意大利西西里岛的锡拉丘兹，在与太阳相反的方向拍摄的。最左边是日落前的天空。向右，突出的波段包括金星带、蓝带、地平线带和红带。当地球的阴影升起时，这些波段的颜色是由地球大气中的空气和气溶胶反射的直射阳光，多次反射（有时包括变红的日落）和折射造成的。实际上，这些波段可能是分散的，难以辨别，它们的颜色可能取决于日落附近的颜色。最后，太阳完全落下，天空变暗了。不要绝望——当太阳在早晨再次升起时，整个事情将会反过来发生。
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How does the sky turn dark at night? In stages, and with different characteristic colors rising from the horizon. The featured image shows, left to right, increasingly late twilight times after sunset in 20 different vertical bands. The picture was taken last month in Syracuse, Sicily, Italy, in the direction opposite the Sun. On the far left is the pre-sunset upper sky. Toward the right, prominent bands include the Belt of Venus, the Blue Band, the Horizon Band, and the Red Band. As the dark shadow of the Earth rises, the colors in these bands are caused by direct sunlight reflecting from air and aerosols in the Earth's atmosphere, multiple reflections sometimes involving a reddened sunset, and refraction. In practice, these bands can be diffuse and hard to discern, and their colors can depend on colors near the setting Sun. Finally, the Sun completely sets and the sky becomes dark. Don't despair -- the whole thing will happen in reverse when the Sun rises again in the morning.
© Dario Giannobile