2025年7月11日
The Veins of Heaven
Image Credit & Copyright: P-M Hedén (Clear Skies, TWAN)
Explanation: Transfusing sunlight as the sky grew darker, this exceptional display of noctilucent clouds was captured on July 10, reflected in the calm waters of Vallentuna Lake near Stockholm, Sweden. From the edge of space, about 80 kilometers above Earth’s surface, the icy clouds themselves still reflect sunlight, even though the Sun is below the horizon as seen from the ground. Usually spotted at high latitudes in summer months, the night shining clouds have made a strong showing so far during the short northern summer nights. Also known as polar mesopheric clouds they are understood to form as water vapor driven into the cold upper atmosphere condenses on the fine dust particles supplied by disintegrating meteors or volcanic ash.
Tomorrow’s picture: light-weekend
天空的脉络─夜光云
影像提供与版权: P-M Hedén (Clear Skies, TWAN)
说明: 这片摄于7月10日、极为鲜明的夜光云，于天黑后不断向夜空输送阳光，并在瑞典斯德哥尔摩市附近静谧的瓦伦蒂纳湖面投下倒影。当这片位于离地表80公里太空边缘的冰晶云，仍在反射阳光时，从地面看出去，太阳早已没入地平线之下。通常出现在夏季高纬度地区的夜光云，在每年短短的夏夜里极为活耀。这种亦名为极区中气层云的云种，是以进入低温上层大气的水气及碎裂流星或火山灰微粒为凝结核而成云。
明日的图片: light-weekend
