A new discovery made by an international team of scientists analyzing atmospheric data gathered by telescopes at Svalbard Island, Norway, at a latitude of 79° north, reveals for the first time that part of the glow of the Northern Lights is polarized--a state that, until now, was thought to be an impossibility.
The new discovery is vitally important to atmospheric scientists as they continue to try to better understand the mystery of one of the most complex natural phenomena of our world: the Earth's atmosphere.
Another thing the new discovery could help scientists understand is the shaping of the Sun's magnetic field as it wraps around the Earth and other planets. The Sun's magnetic field interactions with the Earth's can affect Earthly events to a certain extent, such as by causing disruptions in electronic communications devices.
It has previously been discovered by analyzing data gathered by NASA's Polar spacecraft and the Imager for Magnetopause-to-Aurora Global Exploration (IMAGE) spacecraft that, again contrary to a previously held belief, the Earth's nothern and southern aurorae are not mirror images of each other, due to asymmetric wrapping of the Sun's charged solar wind around the different hemispheres of the Earth as that wind interacts with the Earth's magnetosphere. The magnetosphere is a sheath that at once protects and interacts with the Sun's solar wind.
When charged particles from the Sun are able to penetrate the Earth's magnetosphere, this penetrative interaction is what engenders the auroral lights.
NASA's THEMIS (“Time History of Events and Macroscale Interactions during Substorms”) fleet of five deployed spacecraft, launched in February of 2007, has already observed an aurora-producing geomagnetic storm that packed the energetic equivalent of a 5.5 magnitude earthquake.
One of the most exciting (to scientists) events that can take place due to the Sun's solar wind impacting the Earth's magnetosphere is called a "substorm", and it actually re-shapes the Earth's magnetic sheath. When substorms peak, they cause a dynamic increase in the intensity and activity of aurorae.
A polarized light beam has all of its electromagnetic waves oriented in the same direction or at the same angle, and this is a property that scientists had believed to be impossible in the Earth's upper atmosphere because of collisions between light-energized atoms and gas molecules, collisions which cause de-polarization.
According to Jean Lilensten
of the Laboratory of Planetology of Grenoble, France, the discovery of weakly polarized red light resulting from collisions with oxygen atoms at approximately 140 miles above the Earth's surface "opens a new field in planetology."