Saturday, June 30, 2007
Noctilucent Clouds from Space
NASA has released the first photos of noctilucent clouds (clouds that give off light at night) taken from space. NASA's Spaceweather website has the news.
For the first time ever, humans know what a noctilucent cloud (NLC) looks like--from above. NASA's AIM spacecraft took this composite UV-wavelength picture [above] on June 11th from a vantage point 600 km over Earth's north pole.
Launched on April 25, 2007, AIM is on a mission to study these mysterious clouds at the edge of space; the image above represents its first good look. For the next two years, AIM will monitor the life cycle of NLCs, assaying their chemistry and particulate content, and checking to see if space dust plays a role in their genesis.
When NLCs were first sighted in the 19th century, they were confined to polar latitudes, but lately they have intensified and spread with sightings in recent years as far south as Colorado and Utah. "It is clear that these clouds are changing, a sign that a part of our atmosphere is changing and we do not understand how or what it means," says AIM principal investigator James Russell III of Hampton University. Are NLCs a sign of global warming? Or something else? Researchers hope AIM will provide some answers. Stay tuned for updates.
Check out the gallery of noctilucent photos taken from the ground too.