2013 is shaping up to be a memorable time to view the sky spectacle known as the Northern Lights. The lights are the result of electrically charged particles from the sun bouncing into each other as they enter Earth's atmosphere. Also known as the Aurora Borealis in northern latitudes, or the Aurora Australis (or the southern lights), depending upon the pull of the Earth's magnetic field.
The Northern Lights photographed from the International Space Station. Astronaut Mike Hopkins, aboard the ISS, shared this picture on October 9, 2013, saying, "The pic doesn't do the Northern Lights justice. Covered the whole sky. Truly amazing!" To paraphrase the immortal Smokey Robinson, we second that emotion.
The Northern Lights occur in a circular band around the geomagnetic north pole, otherwise known as the Northern Lights oval. It is a result of the atmosphere shielding the Earth against solar particles which would otherwise make the planet uninhabitable. On their way down toward the geomagnetic poles, the solar particles are stopped by Earth's atmosphere, which acts as an effective shield against these deadly particles. When the solar particles are stopped by the atmosphere, they collide with the atmospheric gases present, and the collision energy between the solar particle and the gas molecule is emitted as a photon -- a light particle. And when you have many such collisions, you have an aurora -- lights that may seem to move across the sky.
In this image, the Aurora Borealis glows in the sky in the Greenland town of Kangerlussuaq.