暮光时分的地球

2020 April 22

Planet Earth at Twilight
Image Credit: ISS Expedition 2 Crew, Gateway to Astronaut Photography of Earth, NASA

Explanation: No sudden, sharp boundary marks the passage of day into night in this gorgeous view of ocean and clouds over our fair planet Earth. Instead, the shadow line or terminator is diffuse and shows the gradual transition to darkness we experience as twilight. With the Sun illuminating the scene from the right, the cloud tops reflect gently reddened sunlight filtered through the dusty troposphere, the lowest layer of the planet’s nurturing atmosphere. A clear high altitude layer, visible along the dayside’s upper edge, scatters blue sunlight and fades into the blackness of space. This picture was taken in June of 2001 from the International Space Station orbiting at an altitude of 211 nautical miles. Of course from home, you can check out the Earth Now.

Celebrate: Today is Earth Day

Tomorrow’s picture: Planet Earth at Night

暮光时分的地球
影像提供: ISS Expedition 2 Crew, Gateway to Astronaut Photography of Earth, NASA

说明: 在这张呈现地球海洋和云彩的壮丽影像里，当日夜交替时，并没有明显的边界分隔白画与黑夜。明暗界线是一个弥漫的区域，白画区缓慢的转变为黑夜，带来暮光时分。在这张影像里，阳光从右方入射，当它们穿过烟尘弥漫、滋养地球万物的对流层时，会逐渐变红，然后再被云层反射产生影像淡红的色泽。在影像右上角的白画地球边缘，可以清楚看见平流层顶，以及受到散射的泛蓝色光逐渐隐没在黝黑的太空中。这幅影像是在2001年7月，摄于轨道高390公里的国际大空站上。不过如今端坐家中的你，可以上线观看地球的现况。

庆祝: 地球日

明日的图片: Planet Earth at Night