"The cartoon cloud ... strokes across the blue." In contrast to the Cirrus clouds, there's the Cumulonimbus storm cloud, "which reaches up maybe eight miles into the sky, spreads out at the ...

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 ...