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APOD

Astronomy Picture of the Day

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

See Explanation. Clicking on the picture will download the highest resolution version available.

Noctilucent Clouds over Moscow

Explanation: This panoramic night scene from June 8 looks out across a Moscow skyline from atop the main building of Lomonosov Moscow State University. Shining in the darkened sky above are widespread noctilucent clouds . From the edge of space, about 80 kilometers above Earth's surface, the icy clouds can still reflect sunlight even though the Sun itself is below the horizon as seen from the ground . Usually spotted at high latitudes in summer months the diaphanous apparitions, also known as polar mesospheric clouds, have come early this season . The seasonal clouds are understood to form as water vapor driven into the cold upper atmosphere condenses on the fine dust particles supplied by meteor smoke (debris left by disintegrating meteors) or volcanic ash. Their early start this year may be connected to changing global circulation patterns in the lower atmosphere. During this northern summer, NASA's AIM mission provides daily projections of the noctilucent clouds as seen from space .

Date June 27, 2013
Credit Image Credit & Copyright: Sergey Lisakov
Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
A service of: ASD at NASA / GSFC,
NASA Science Activation & Michigan Tech. U.