2011 March 28
This APOD is not on a image but actually a video of the auroras over Norway. These auroras in the video were recorded in the north in locations like the border between Norway and Russia. The video shows a time-lapse movie of auroras in a nature setting. There are scenes of the mountains, trees, and lakes near Kirkenes, Norway. Auroras are formed from emissions of photons in the Earth's upper atmosphere from ionized nitrogen regaining an electron and oxygen and nitrogen atoms returning from an excited state to a ground state. They are ionized or excited by the collision of solar wind particles being accelerated along the Earth's magnetic field lines. When they emit a photon of light or collide with another atom or molecule their excitation energy is lost and the return to a ground state. Oxygen emissions produce green or brownish-red auroras depending on the amount of energy absorbed. Nitrogen emissions produce blue or red auroras. The sun is predicted to be more active the next few years so there should be more auroras occurring, possibly even in locations closer to the equator. I really like this apod because I have only seen images of auroras. Seeing an aurora in action makes it even greater and more beautiful. It was also really cool to see the stars in the background and sometimes a streak of light could be seen traveling across the sky.
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