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.

2007 December 29
See Explanation.  Clicking on the picture will download
 the highest resolution version available.

Saturn's Infrared Glow
Credit: VIMS Team, U. Arizona, ESA, NASA

Explanation: Known for its bright ring system and many moons, gas giant Saturn looks strange and unfamiliar in this false-colour view from the Cassini spacecraft. In fact, in this Visual and Infrared Mapping Spectrometer (VIMS) mosaic the famous rings are almost invisible, seen edge-on cutting across picture centre. The most striking contrast in the image is along the terminator or boundary between night and day. To the right (day side) blue-green hues are visible sunlight reflected from Saturn's cloud tops. But on the left (night side) in the absence of sunlight, the lantern-like glow of infrared radiation from the planet's warm interior silhouettes features at Saturn's deeper cloud levels.

APOD presents: Astronomy Pictures of the Year for 2007
Tomorrow's picture: cloudy day


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