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NASA mission launched to unveil secrets of Northern Lights
Published: Sunday February 18, 2007
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The US space agency NASA has launched its first five-satellite mission on board a single rocket aiming to unlock the age-old mysteries of the aurora borealis.

The two-year mission, dubbed THEMIS -- an acronym for Time History of Events and Macroscale Interactions during Substorms -- was launched successfully late Saturday after a 24-hour delay, NASA said in a statement.

"The mission will help resolve the mystery of what triggers geomagnetic substorms," the space agency said on its website.

"The findings from the mission may help protect commercial satellites and humans in space from the adverse effects of particle radiation."

Once deployed, the satellites will align below North America every four days to observe the formation of the aurora borealis, a bright play of lights in the night sky above the polar area, commonly known as the Northern Lights.

On the ground, stations in Alaska and in Canada will photograph the multicolored phenomena.

"This is a challenging project that will replace old myths with scientific explanations for the lights' visible evidence of the earth's magnetosphere protecting us from the fatal effects of the solar wind," said Frank Snow, the National Aeronautics and Space Administration's THEMIS mission manager.

Scientists hope that the five satellites operating jointly will be able to identify the precise location of where the aurora borealis starts.

Scientists currently believe that the lights are caused by solar winds that are deformed when they reach the earth's magnetic field, forming a tail of sorts when caught in the wind.

The energy stored in this "tail" is released sporadically, causing substorms at the equator and then spreading out towards the north and south poles, where it produces the aurora borealis phenomenon.

While scientists have a good idea how this works, they have been unable to explain where in the magnetosphere the energy of solar wind tranforms into the spectacular phenomenon of lights.