+ Visit NASA.gov + Advanced Search   + About the Server   + Animation List   + How to Use the Server   + RSS Feeds Previous Animation Next Animation Aurora over the North Pole on April 17, 1999 (WMS) When the charged particles flowing outward from the Sun (the solar wind) hit the Earth's magnetic field, they are channeled down the magnetic field lines to the ionosphere at the North and South Poles. The impact of these particles on atmospheric molecules causes the molecules to emit light, which forms the visible aurora. This visualization shows the development of the aurora over the North Pole for about three hours on April 17, 1999, as seen by the ultraviolet VIS Earth Camera on the POLAR spacecraft. The two main features of these ultraviolet images are the very bright ultraviolet emission from the reflected solar radiation on the dayside of the Earth and the bright ring of the auroral oval circling the North Pole. The aurora seen in this visualization is the diffuse aurora, a very large bright band that is actually too dim to be seen well from the ground by the human eye. What we normally think of as the aurora are the even brighter curtains of light within the diffuse auroral caused by very energetic electrons. These curtains are too small to be seen in this image. The diffuse aurora appears as a ring around the pole rather than as a bright spot over the entire pole because the solar particles actually spend extended time wandering about within the Earth's magnetic field before traveling down a very select set of magnetic field lines to the Earth. Near the end of this three hour period, the spacecraft was getting so close to the Earth that the edges of the globe were outside the camera's image, which accounts for the growing circular data gaps over Asia and the Pacific Ocean.    This animation shows the aurora over the Northern Hemisphere as recorded by the Polar satellite on April 17, 1999. Duration: 7.0 seconds Available formats:   360x100 (29.97 fps) MPEG-1   2 MB   160x80       PNG           20 KB   320x89       GIF           19 KB   80x40         PNG           5 KB How to play our movies This product is available through our Web Map Service.   Click here to learn more.    The colorbar for the aurora animation, where counts is a measure of the intensity of ultraviolet light being emitted by charged particle impacts in the upper atmocphere of the Earth. Available formats:   320 x 90           PNG   1 KB Animation Number: 2891 Animators: Eric Sokolowsky (SVS) (Lead)   Greg Shirah (SVS)   Horace Mitchell (SVS) Completed: 2004-07-09 Scientists: David Chenette (LMATC)   John B. Sigwarth (University of Iowa)   Mike Carlowicz (NASA/GSFC) Instrument: Polar/VIS Data Collected: 1999/04/17 (00 49 27 UT to 04 25 05 UT) Series: WMS Keywords: SVS >> Aurora SVS >> Electron Fluxes DLESE >> Geophysics DLESE >> Space science SVS >> Upper Atmosphere GCMD >> EARTH SCIENCE >> Sun-earth Interactions >> Ionosphere/Magnetosphere Particles >> Aurorae More Information on this topic available at: http://eiger.physics.uiowa.edu/~vis/images/ Google Earth KML file is available here. DEPC Metadata is available here.     Please give credit for this item to NASA/Goddard Space Flight Center Scientific Visualization Studio Back to Top + Privacy Policy and Important Notices + Reproduction Guidelines NASA Official: SVS Contact: Curator: