THE NITROGEN FRINGE: Over the weekend, a high-speed stream of solar wind buffeted Earth's magnetic field, sparking big green auroras around the Arctic Circle.

Last night in Utsjoki, Finland, Tiina Salonen of Aurora Holidays noticed something extra--a fringe of pink: [link to spaceweather.com]

This is a "nitrogen fringe." Most auroras are green--the color of oxygen atoms being struck by energetic particles from space between 100 km and 300 km above Earth's surface. Pink appears when energetic particles descend lower than usual, striking nitrogen molecules at the 100 km level and below.
"Auroras--both pink and green--danced all above us on Jan. 6th," says Salonen. "It was absolutely stunning!"

There is anecdotal evidence that Solar Minimum produces an unusual number of pink and even white auroras. Why? The "flavor" (chemical and magnetic composition) of solar wind during Solar Minimum may differ from other phases of the solar cycle, producing its own palette of color. If so, more pink lights may be in the offing on Jan. 7th as the solar wind continues to blow.

[link to spaceweather.com]