Friday, February 22, 2013

APOD 3.5

12 Feb 2013 Reflected Aurora Over Alaska

See Explanation.
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available.

An aurora is a glow in the upper atmosphere created by energy particles entering the atmosphere from space.  The magnetosphere provides the particles that create auroras seen from Earth.  The colors are determined by the composition and density of the atmosphere where it is created.  A subvisual aurora is one which cannot be seen with the naked eye and requires a camera to view.  This image features both visual and subvisual auroras; the green were visible to the naked eye but the red areas only appeared in the captured image.  The reason for this increased visibility through the lens of a camera is that cameras offer more exposure time than the human eye which only collects light for fractions of seconds at a time.  This image was taken in Anchorage, Alaska and features the Pleiades star cluster and Jupiter.  These red and green auroras were most likely created by oxygen particles.

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