As Big Island astronomers recently observed, the planet Jupiter — unlike tigers — can change its stripes.
Last spring, the dark brown stripe that circled the planet just below the equator appeared to turn white. In fact, scientists believe, downwelling winds that usually kept the region clear of clouds probably died down, allowing high-floating clouds of white ammonia ice to obscure the brown material that floats below.
(The so-named South Equatorial Belt turns completely white every few decades and remains that way for one to three years at a time. Scientists still do not know why.)
Now there is evidence that the band is starting to reappear.
Earlier this month, amateur astronomer Christopher Go of the Philippines noticed a bright spot in the area where the dark band was.
Follow-up observations on Mauna Kea by NASA’s Infrared Telescope Facility, the W.M. Keck Observatory and the Gemini Observatory confirmed that dark brown material was visible to the left of the bright spot, indicating a clearing in the white cloud cover.
According to a NASA release, the event is significant because it is the first time scientists have been able to use modern instruments to "determine the details of the chemical and dynamical changes of this phenomenon."
NASA’s Juno spacecraft is due to arrive at Jupiter in 2016. A larger mission to orbit Jupiter and explore its moon Europa has been proposed for 2020.