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Data acquired July 22, 2008 540 x 405 JPEG
Data acquired July 22, 2008 1000 x 664 265 KB - JPEG
Data acquired July 22, 2008 JPEG
Polar mesospheric clouds (also known as noctilucent, or “night-shining” clouds) are transient, upper atmospheric phenomena that are usually observed in the summer months at high latitudes (greater than 50 degrees) of both the Northern and Southern Hemispheres. They appear bright and cloudlike while in deep twilight. They are illuminated by sunlight when the lower layers of the atmosphere are in the darkness of Earth’s shadow.
Astronaut photograph ISS017-E-11632 was acquired at 18:24:01 Greenwich Mean Time on July 22, 2008, with a Nikon D2Xs digital camera fitted with an 180 mm lens, and is provided by the ISS Crew Earth Observations experiment and the Image Science & Analysis Laboratory, Johnson Space Center. The image was taken by the Expedition 17 crew. The image in this article has been cropped and enhanced to improve contrast. Lens artifacts have been removed. The International Space Station Program supports the laboratory to help astronauts take pictures of Earth that will be of the greatest value to scientists and the public, and to make those images freely available on the Internet. Additional images taken by astronauts and cosmonauts can be viewed at the NASA/JSC Gateway to Astronaut Photography of Earth. Caption by Michael Trenchard, NASA-JSC.
Published August 4, 2008 Data acquired July 22, 2008