Auroras Studied by Satellites with Name Only Mother Could Love

Aurora at Acadia National Park, 2005 For many of us who do not live close to the poles (say, south of Canada for the Northern Hemisphere), a view like this is quite rare. They’re the Aurora Borealis, strange northern lights which are relatively common occurrences during the spring and fall equinoxes. But despite being described by humans for centuries, we’re only marginally closer to understanding why and how they happen at all.

NASA is trying to change that. With THEMIS.

THEMIS (Get ready: Time History of Events and Macroscale Interactions during Substorms) is a fleet of 5 spacecraft launched in February 2007 tasked with the job of studying these auroras. Already, a series of observations has yielded clues to how auroras occur, but THEMIS still has 2 years left in it’s lifespan to provide a better picture.

Still, for now scientists have use THEMIS data to show that there are “ropes” of magnetism that link the earth to the sun, over which streams of solar wind travel and seemingly provide the energy to feed the auroras. And, it appears that the earth’s 23 degree tilt provides a favorable alignment for these ropes, presumably because it’s during the equinoxes that either pole “points” moreso toward the sun than at other times.

I’m not sure what NASA hopes to do once they unravel the great aurora mystery. They say they’re out to help minimize the risks to orbiting satellites. But it seems to me that this study makes for an excuse to get in some springtime camping while brushing up on nighttime photography. Personally, I’d enjoy the latter.

Source: NASA
Photo: National Geographic, Michael Melford

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