Noctilucent Clouds /Polar Mesospheric Clouds
Taken by Iurie Belegurschi on August 2, 2012 @
Iceland
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Camera Used: Canon Canon EOS 5D Mark III
Exposure Time: 13/1
Aperture: f/8.0
ISO: 160
Date Taken: 2012:08:03 02:59:07
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Details:
Night clouds or noctilucent clouds are tenuous cloud-like phenomena that are the ragged-edge of a much brighter and pervasive polar cloud layer called polar mesospheric clouds in the upper atmosphere, visible in a deep twilight. They are made of crystals of water ice. The name means roughly night shining in Latin. They are most commonly observed in the summer months at latitudes between 50° and 70° north and south of the equator. They can only be observed when the Sun is below the horizon.
They are the highest clouds in the Earths atmosphere, located in the mesosphere at altitudes of around 76 to 85 kilometres (47 to 53 mi). They are normally too faint to be seen, and are visible only when illuminated by sunlight from below the horizon while the lower layers of the atmosphere are in the Earths shadow. Noctilucent clouds are not fully understood and are a recently-discovered meteorological phenomenon; there is no record of their observation before 1885.
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