蓝带血月
(原标题: A Blue-Banded Blood Moon)
2021-12-01
浏览次数: 33
在月食期间，是什么导致蓝色带穿过月球？蓝色波段是真实存在的，但通常很难看到。然而，这张上周月食的HDR图像——拍摄于中国盐城——经过了数字处理，平衡了月亮的亮度，夸大了颜色。右下角的灰色是月亮的自然颜色，直接被阳光照射。月球的左上角没有被太阳直接照亮，因为它被日食了——它在地球的阴影里。不过，由于穿过地球大气层深处的阳光，它的光线很微弱。月球的这一部分是红色的，被称为血月，原因和地球的日落是红色的一样：因为空气散射掉的蓝光比红光多。不寻常的蓝色波段是不同的——它的颜色是由穿过地球大气层的阳光产生的，在地球大气层中，红光比蓝光更容易被臭氧吸收。本周末将发生日全食，但不幸的是，日全食只能在地球南极附近看到。几乎超空间：随机APOD生成器
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What causes a blue band to cross the Moon during a lunar eclipse? The blue band is real but usually quite hard to see. The featured HDR image of last week's lunar eclipse, however -- taken from Yancheng, China -- has been digitally processed to equalize the Moon's brightness and exaggerate the colors. The gray color of the bottom right is the Moon's natural color, directly illuminated by sunlight. The upper left part of the Moon is not directly lit by the Sun since it is being eclipsed -- it in the Earth's shadow. It is faintly lit, though, by sunlight that has passed deep through Earth's atmosphere. This part of the Moon is red -- and called a blood Moon -- for the same reason that Earth's sunsets are red: because air scatters away more blue light than red. The unusual blue band is different -- its color is created by sunlight that has passed high through Earth's atmosphere, where red light is better absorbed by ozone than blue. A total eclipse of the Sun will occur this weekend but, unfortunately, totality be visible only near the Earth's South Pole. Almost Hyperspace: Random APOD Generator