Noctilucent clouds, Earth's highest clouds, shine blue in the twilight sky from late May to August in the northern hemisphere ...

The clip posted by @verivanessa shows a large cloud at sunrise appearing to sit just above the horizon, with a long, dark rectangular beam stretching across an orange-pink sky. A note overlaid on ...

MOLINE, Ill — Perhaps one of the strangest appearing things in the sky you'll ever witness, this unique cloud formation comes in different sizes and shapes. It is, however, usually caused by the ...