Noctilucent Clouds

[Sarah90]

"NOCTILUCENT CLOUDS:  On May 5th, experienced sky watchers in Northern Ireland were surprised by a sudden apparition of electric-blue noctilucent clouds (NLCs). This marks an unusually early beginning to the 2008 NLC season and may herald a spectacular summer of high-latitude "night shining" clouds. NLCs first appeared in the 19th century mainly around Earth's poles. Since then, for reasons unknown, they have increased in number and range, with sightings in recent years as far south as Utah and Colorado.  Visit http://spaceweather.com to see the first photos of 2008 and to learn what to look for in case NLCs visit your part of the world in the nights ahead."http://spaceweather.com/nlcs/gallery2007_page1.htm

[Orstio]

Fascinating.  Thanks, Sarah.

http://science.nasa.gov/headlines/y2003/19feb_nlc.htm