蓝带血月
(原标题: A Blue Banded Blood Moon)
2025-03-25
浏览次数: 47
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——拍摄于美国俄克拉何马州的诺曼——经过了数字处理，夸大了色彩。顶部月球图像右上方的灰色是月球的自然颜色，直接被阳光照射。在这三张图片中，月球的下半部分都没有被太阳直接照亮，因为它正在被日食——它处于地球的阴影中。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。在上面和中间图像的右上方可见的不寻常的紫蓝色带是不同的——它的颜色是由穿过地球大气层的阳光增强的，在地球大气层中，红光比蓝光更容易被臭氧吸收。《天体惊喜》：APOD在你生日那天给你拍了什么照片？(1995后)
查看原文解释
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 Norman, Oklahoma (USA) -- has been digitally processed to exaggerate the colors. The gray color on the upper right of the top lunar image is the Moon's natural color, directly illuminated by sunlight. The lower parts of the Moon on all three images are not directly lit by the Sun since it is being eclipsed -- it is 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 purple-blue band visible on the upper right of the top and middle images is different -- its color is augmented by sunlight that has passed high through Earth's atmosphere, where red light is better absorbed by ozone than blue. Celestial Surprise: What picture did APOD feature on your birthday? (post 1995)
© Zixiong Jin