TopRq.com

rss_follow  tubmlr_follow twitter_follow


Rate this file (Rating : 5 / 5 with 1 votes)
aurora, amazing northern lights

Aurora, Amazing Northern Lights

On 26 February 2008, THEMIS probes were able to determine, for the first time, the triggering event for the onset of magnetospheric substorms. Two of the five probes, positioned approximately one third the distance to the moon, measured events suggesting a magnetic reconnection event 96 seconds prior to auroral intensification. Dr. Vassilis Angelopoulos of the University of California, Los Angeles, the principal investigator for the THEMIS mission, claimed, "Our data show clearly and for the first time that magnetic reconnection is the trigger."
Still more evidence for a magnetic connection are the statistics of auroral observations. Elias Loomis (1860) and later in more detail Hermann Fritz (1881) and S. Tromholt (1882) established that the aurora appeared mainly in the "auroral zone", a ring-shaped region with a radius of approximately 2500 km around Earth's magnetic pole. It was hardly ever seen near the geographic pole, which is about 2000 km away from the magnetic pole. The instantaneous distribution of auroras ("auroral oval") is slightly different, centered about 3–5 degrees nightward of the magnetic pole, so that auroral arcs reach furthest towards the equator about an hour before midnight. The aurora can be seen best at this time, called magnetic midnight, which occurs when an observer, the magnetic pole in question and the Sun are in alignment

File information
Filename:127152.jpg
Album name:Earth & Universe
Rating (1 votes):55555
Keywords:#aurora #amazing #northern #lights
Filesize:55 KiB
Date added:Jun 08, 2009
Dimensions:766 x 512 pixels
Displayed:29 times
URL:displayimage.php?pid=127152
Favorites:Add to Favorites