
Brilliant splashes of color lit up the night skies across North America on May 14-15, as seen in these two stunning photos of aurora borealis, better known as the "northern lights."
Auroras form when a "solar wind" of charged particles from the Sun enters Earth's magnetic field, accelerating electrically charged particles trapped within. The high-speed particles then crash into Earth's upper atmosphere over the polar regions, causing the atmosphere to emit a ghostly, multicolored glow.
Top Photo: Five miles outside Kearney Nebraska. Credit: Mark Urwiller.
Bottom Photo: St. Francis, Wisconsin. Credit: Jesús Orjeda.
These photographs and many other aurora images are available on http://www.spaceweather.com.
+ Full Size Version of Top Image