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PURPLE AURORAS: Auroras are dancing around the Arctic Circle and some of them are purple. This is how the sky looked on Sept. 8th over Bø, Norway:

"It's not often I get to see purple auroras," says photographer Øystein Lunde Ingvaldsen. "This was truly a fantastic sight!"

Auroras get their colors from specific atoms and molecules in Earth's atmosphere. Green comes from oxygen molecules excited by geomagnetic activity. Purple, on the other hand, is usually a mixture of red and blue emissions from molecular nitrogen. O2 and N2 were both revved up in Norway last night!

More purple is possible tonight as a solar wind stream continues to buffet Earth's magnetic field. High-latitude sky watchers should remain alert for auroras.

http://spaceweather.com/archive.php?view=1&day=09&month=09&year=2010