Pictures and albums about Aurora-borealis published in outdoors

"The solar wind is the outermost atmosphere of our sun. The sun is so hot that it boils off its outer layers, and the result is a constant outward expanding very thin gas. This solar wind consists not of atoms and molecules but of protons and electrons (this is called a plasma). Embedded in this solar wind is the magnetic field of the sun. The density is so low that we may well call it a vacuum. However tenuous it is, when this solar wind encounters a planet, it has to flow around it. When this planet has a magnetic field, the solar wind sees this magnetic field as an obstacle, as protons and electrons cannot move freely across a magnetic field. These charged particles are constrained to move almost always only along the magnetic field. Likewise, when they are forced to move in a specific direction, a magnetic field will move with them or will be bent into the direction of the flow. Whether the magnetic field forces the plasma motion or whether the plasma motion bends the magnetic field depends on the strength of the field and the force of the motion. When the solar wind encounters Earth's magnetic field, it will thus bend the field unless the field gets too strong. The strength of the magnetic field falls off with distance from Earth. The distance at which the solar wind and the magnetic field of the Earth balance each other is about 60,000 km away, or 1/10 of the distance to the moon. The inside of this volume that is bounded by the solar wind is called the magnetosphere. At the interface of the solar wind and the magnetosphere, energy can be transfered into the magnetosphere by a number of processes. Most effective is a process called reconnection. When the magnetic field in the solar wind and the magnetic field of the magnetosphere are anti-parallel, the fields can melt together, and the solar wind can drag the magnetospheric field and plasma along. This is very efficient in energizing magnetospheric plasma. Eventually, the magnetosphere responds by dumping electrons and protons into the high latitude upper atmosphere where the energy of the plasma can be dissipated. This then results in aurora." ~ source: University of Alaska Fairbanks Geophysical Insitute ~ http://odin.gi.alaska.edu/FAQ/#curtain

Featured Editor's Collection Autumn Landscapes ~ Featured Member's Choice Fall Scenics October 2007