Polar Clouds

This image is entrancing - every time I look at I see more swirls in its murky mists. Its almost hypnotic appeal required a posting.

Quick excerpt from NASA's Earth Observatory:

Click here to view full image (292 kb)

In the summertime in the far northern or southern latitudes, high in the Earth’s atmosphere at the edge of space, thin, silvery clouds sometimes become visible just after sunset. These high clouds, occurring at altitudes of about 80 kilometers (50 miles), are called polar mesospheric clouds (PMCs). They are also called noctilucent (“night-shining”) clouds. In recent years, polar mesospheric clouds seem to be occurring more frequently and at lower latitudes than they have in the past, and studies are underway to determine whether their occurrence is related to global climate change.

Full Story at: http://earthobservatory.nasa.gov/Newsroom/NewImages/images.php3?img_id=17737

Featured astronaut photograph STS117-E-6998 was acquired by the STS-117 crew on June 10, 2007, with a Kodak 760C digital camera using an 180 mm lens, and is provided by the ISS Crew Earth Observations experiment and Image Science & Analysis Laboratory at Johnson Space Center. The image in this article has been enhanced to improve contrast. 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.