Astronomy Picture of the Day

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2010 September 27
See Explanation.  Clicking on the picture will download
 the highest resolution version available.

The Dancing Aurorae of Saturn
Credit: VIMS Team, JPL, ESA, NASA

Explanation: What drives aurorae on Saturn? To help find out, scientists have sorted through hundreds of infrared images of Saturn taken by the Cassini spacecraft for other purposes, trying to find enough aurora images to correlate changes and make movies. Once made, some movies clearly show that Saturnian aurorae can change not only with the angle of the Sun, but also as the planet rotates. Furthermore, some auroral changes appear related to waves in Saturn's magnetosphere likely caused by Saturn's moons. Pictured above, a false-coloured image taken in 2007 shows Saturn in three bands of infrared light. The rings reflect relatively blue sunlight, while the planet itself glows in comparatively low energy red. A band of southern aurora in visible in green. Inspection of many more Saturnian images may well lead to an even better understanding of both Saturn's and Earth's aurorae.

Tomorrow's picture: venusian vortex


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Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
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