But the clouds in the image formed in the mesosphere ... Ice crystals reflect the sunlight and appear as electric blue wisps in the night sky, reaching out toward the edge of space.

Bright blue-white noctilucent clouds danced over the town of Nykøbing Mors in Denmark just before dawn, just when this spectacular photo was taken. Night sky photographer Ruslan Merzlyakov ...

“An angel over the sky above Kiev, Ukraine,” one user wrote on March 2, captioning an image of a purported winged figuration of clouds appearing ... formations over a blue background.

the sky eventually gives way to deep blue while the mountain-life clouds hang on the horizon, the extraordinary pictures show.