Have you ever seen the northern (or southern) lights? Auroras are part of a natural phenomenon that occurs at far northern and southern latitudes.
According to National Geographic, auroras occur when "charged particles [from the sun] flow along Earth's magnetic field lines. The particles hit the atmosphere at the Poles and excite air molecules, which release the extra energy as light."
There were intense northern lights (aurora borealis) early in 2011, due to the strongest solar activity in four years. Several videos emerged from the early 2011 auroras, and they are quite impressive.
Although northern lights are traditionally seen only as far south as the northern United States, they could be seen much further south in October. In fact, northern lights were seen in Missouri and Arkansas. The rare treat was the result of a Coronal Mass Ejection, which is a burst of solar wind.
Check out some of the best images of aurora phenomena from 2011 and vote for your favorites. Be sure to check out these other 2011 aurora photos and this picture from August in which the northern lights, the Big Dipper and Jupiter can all be seen.
Flickr images courtesy of credited users.