Ruddy color of Jupiter's great red spot likelier to be produced by sunlight

A new study from NASA's Cassini mission has revealed that the color of the Jupiter's red spot is likely to be produced due to the effect of sunlight.

The ruddy color of Jupiter's Great Red Spot is likely a product of simple chemicals being broken apart by sunlight in the planet's upper atmosphere.

The results contradict the other leading theory for the origin of the spot's striking color that the reddish chemicals come from beneath Jupiter's clouds.

Kevin Baines, a Cassini team scientist based at NASA's Jet Propulsion Laboratory, Pasadena, and JPL colleagues Bob Carlson and Tom Momary arrived at their conclusions using a combination of data from Cassini's December 2000 Jupiter flyby and laboratory experiments.

Baines said that most of the Great Red Spot was actually pretty bland in color, beneath the upper cloud layer of reddish material and under the reddish "sunburn" the clouds are probably whitish or grayish.

The Great Red Spot is a long-lived feature in Jupiter's atmosphere that is as wide as two earths. Jupiter possesses three main cloud layers, which occupy specific altitudes in its skies; from highest to lowest they are: ammonia, ammonium hydrosulfide and water clouds.

As for why the intense red color is seen only in the Great Red Spot and a few much smaller spots on the planet, the researchers think altitude plays a key role.

Other areas of Jupiter display a mixed palette of oranges, browns and even shades of red. Baines says these are places where high, bright clouds are known to be much thinner, allowing views to depths in the atmosphere where more colorful substances exist.