Jupiter’s Great Red Spot Redux

Jupiter's famed Great Red Spot, the strongest storm in the solar system, has a doppelganger. First formed in 2000, this newest storm, officially called Oval BA and about half the size of the Great Red Spot, has changed color. As late as November 2005, the storm was white. Now Oval BA is the same ruddy hue as the original megastorm. Scientists don't know exactly why the storms are red—some hypothesize that solar ultraviolet radiation causes a chemical reaction that generates the red color—but many believe that an intensifying red color means that the storm itself is growing much stronger. —Martha Harbison