Astronomy Picture of the Day
Discover the cosmos! Each day we feature a different image or photograph
of our fascinating universe, along with a brief explanation written by a
November 14, 1995
Aurora and Orion
Looking toward the south from low Earth orbit, the crew of the
Space Shuttle Endeavor made this stunning time exposure of the
Aurora Australis (southern lights) in April of 1994.
are caused by high energy electrons from the
which are funneled into the atmosphere
Earth's magnetic field.
The reddish colors occur at the highest altitudes (about 200 miles)
where the air is least dense. At lower altitudes and greater densities
green tends to dominate. At the lowest altitudes a pinkish glow is
constellation of Orion the Hunter is clearly
visible above the dark horizon in the background.
Because of the shuttle's orbital motion, the bright stars
Orion appear slightly elongated.
Tomorrow's picture: A Quintet of Galaxies
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