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.

2000 October 3
See Explanation.  Clicking on the picture will download 
 the highest resolution version available.

Saturn Rotates
Credit: HST, NASA

Explanation: The dramatic rotation of the cloud-tops of Saturn every ten-hours is particularly evident from orbit around the gas giant planet. With a good enough telescope, however, such rotation is visible even from Earth, as shown by this time-lapse image sequence from the Hubble Space Telescope taken in November 1990. Particularly evident at that time was a light-colored giant storm cloud system that completely encircled the planet. The storm was not evident twenty years ago during the flybys of the Voyager spacecraft -- a storm of this magnitude was last noted in 1933. Studying the complex atmosphere of Saturn will be one objective of the Cassini spacecraft launched by NASA in 1997 and expected to arrive in 2004.

Tomorrow's picture: Barred Spiral Galaxy

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Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (USRA)
NASA Technical Rep.: Jay Norris. Specific rights apply.
A service of: LHEA at NASA/GSFC
& Michigan Tech. U.