Noctilucent Clouds Observed Over Ørsta, Norway
September 02, 2015
This impressive display of electric-blue-white noctilucent clouds was observed over Ørsta, Norway, in the early hours of August 4, 2015. These polar mesospheric clouds take shape 30 to 55 mi (50 to 87 km) above the Earth’s surface as water vapor condenses around small particles that are thought to be of meteoric origin. Noctilucent clouds are usually only seen during summer nights -- when the Sun is about 6 and 16 degrees below the horizon. Structure in this display was especially evident when an upper atmosphere wave drifted over the peaks of the Sunnmøre Alps. Photo taken at 2:30 a.m.