Astronomy Picture of Day: Noctilucent Clouds over Sweden# Astronomy - 天文
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octilucent Clouds Over Sweden
Credit: P-M Hed閚
Explanation: Sometimes it's night on the ground but day in the air. As the
Earth rotates to eclipse the Sun, sunset rises up from the ground. Therefore,
at sunset on the ground, sunlight still shines on clouds above. Under usual
circumstances, a pretty sunset might be visible, but unusual noctilucent
clouds float so high up they can be seen well after dark. Pictured above last
month, a network of noctilucent clouds cast a colorful but eerie glow aft
Credit: P-M Hed閚
Explanation: Sometimes it's night on the ground but day in the air. As the
Earth rotates to eclipse the Sun, sunset rises up from the ground. Therefore,
at sunset on the ground, sunlight still shines on clouds above. Under usual
circumstances, a pretty sunset might be visible, but unusual noctilucent
clouds float so high up they can be seen well after dark. Pictured above last
month, a network of noctilucent clouds cast a colorful but eerie glow aft