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Aurora Borealis from Barrow, Alaska

The photo above shows a bright green aurora commanding the night sky over Point Barrow, Alaska as observed on March 9, 2012 with the camera facing northeast. Intense solar storms (solar flares) the first week of March ignited these striking northern lights.

High-speed particles (solar wind) generated by solar flares are guided along magnetic field lines as they near the Earth. These particles excite electrons primarily in oxygen and nitrogen atoms of the upper atmosphere above the poles. Oxygen emits most strongly in the green portion of the electromagnetic spectrum. In this case it’s mostly the oxygen atoms that have been excited.

That’s the Moon, not the Sun, rising over sea ice in the Arctic Ocean.

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