Monday, July 20th 2009, 1:56 PM EDT
Updated below by Jo D'aleo
Photographers and other sky watchers in Omaha, Paris, Seattle, and other locations
have run outside to capture images of what scientists call noctilucent (”night shining”) clouds. Formed by ice literally at the boundary where the earth’s atmosphere meets space 50 miles up, they shine because they are so high that they remain lit by the sun even after our star is below the horizon.
Nobody knows for sure, but most of the answers seem to point to human-caused global atmospheric change.
Updated by Jo D'aleo
Recently spaceweather.com found an example of noctilucent clouds resulting from space shuttle passage
ALSO from Spaceweather.com
"There is a well-known correlation between noctilucent clouds and the solar cycle: NLC activity tends to peak during years of solar minimum, possibly because low solar activity allows the upper atmosphere to cool, promoting the growth of ice crystals that make up the clouds. With a century-class solar minimum underway, the stage is set for NLCs."
UPDATED: 2009 Noctilucent Photo Gallery
Click source link to read FULL report
Mysterious, glowing clouds previously seen almost exclusively in Earth’s polar regions have appeared in the skies over the United States and Europe over the past several days.