APOD: 2026 October 27 – Noctilucent Clouds over Sweden
The post APOD: 2026 October 27 – Noctilucent Clouds over Sweden appeared first on NASA Science .
Today's Astronomy Picture of the Day reveals Noctilucent Clouds over Sweden. The phenomenon occurs when it's night on the ground yet day in the air. As the Earth rotates and the Sun sets, the sunlight still reaches clouds located high above. Noctilucent clouds, also known as polar mesospheric clouds, are the highest in the atmosphere and were photographed in early August above Linköping, Sweden.
They appear silhouetted against a backdrop of green grass and stark trees. Despite being too dim to see under normal circumstances, these clouds can be visible just after sunset during the summer, illuminated by sunlight from below the horizon. The exact formation and evolution of noctilucent clouds remains a subject of ongoing research.
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