On Sunday morning, July 10th, a bank of noctilucent clouds (NLCs) swept across Europe. Instead of the usual rosy-red, the sunrise over Poland was electric blue:

Poland NLCs
© Marek NikodemImage Taken: Jul 10, 2011
Location: Szubin, Poland
"This morning I witnessed a spectacular display of NLCs--the best I've ever seen," reports photographer Marek Nikodem of Szubin, Poland. "The clouds were more than 180 degrees wide and 100 degrees high. It was a fantastic show."

Poland NLCs_1
© Marek NikodemImage Taken: Jul 10, 2011
Location: Szubin, Poland
July 2011 has been a banner month for these mysterious clouds. Normally confined to polar latitudes, NLCs have been sighted in recent nights as far south as France in Europe and Kansas and Colorado in the United States. Sky watchers at all latitudes are encouraged to be alert for electric blue; observing tips may be found in the 2011 NLC photo gallery.

Image
© Marek Nikodem
Image
© Marek Nikodem