APOD: 2026 October 27 – Noctilucent Clouds over Sweden
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APOD Science APOD APOD: 2026 October 27 –… Today’s APOD Archive Submissions Index Search Calendar RSS Education About Discuss APOD Astronomy Picture of the Day Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer. Noctilucent Clouds over […]
APOD
Astronomy Picture of the Day
Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
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. Normally too dim to be seen, they may become visible just after sunset during the summer when illuminated by sunlight from below the horizon. Noctilucent cloud s are the highest clouds and are known more technically as polar mesospheric clouds . Featured here as they appeared in early August, a network of blue noctilucent clouds was captured in the distant sky above a field of green grass near Linköping , Sweden , with trees in stark silhouette across the horizon. Much about noctilucent clouds has been discovered only in the past two decades, while how they form and evolve remains a topic of active research .
Tomorrow’s picture: round and round
Yesterday’s Image APOD: 2026 October 26 – M42: The Great Nebula in Orion