The ethereal light of a lunar fog bow made of moonlight and fog glows over a Finland lake in this beautiful night sky photo.
Finnish photographer Thomas Kast took this stunning shot on a cold, foggy night around 1 a.m. local time on Aug. 25, from Yli-Ii, Finland.
Similar to a rainbow, tiny water droplets that cause fog reflect light. Lunar fog bows typically appear white because sunlight reflected from the moon is weak. Some photographers have also captured so-called "moonbows," which are similar to rainbows in that they do include colors.
The lunar fog bows lack of colors is caused by the smaller water drops … so small that the wavelength of light becomes important. Diffraction smears out colors that would be created by larger water drops in rainbows, according to NASA.
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