Friday, May 21, 2010
Jupiter Loses a Stripe
On May 9, Australian astronomer Anthony Wesley obtained the photo on the left revealing that the Southern Equatorial Belt (SEB) of Jupiter has faded from view. This is not the first time that the SEB has faded. It fades from view every 3-15 years. Nor was the observation a sudden surprise. In 2009 astronomers had been following the developments, but Jupiter went behind the sun for several months and only re-emerged in March. (Aside: I do not understand why the Great Red Spot is not visible in the right hand image. Am trying to follow up on this.)
The SEB is composed primarily of ammonia ice. One theory is that the belts of Jupiter are lower levels of the atmosphere revealed by gaps in the higher paler clouds. If this is true, then one possibility for the disappearance of the SEB is that it is simply obscured by higher level clouds that have returned to this latitude.
The reappearance of the SEB will occur in perhaps the next year or two, and the event is predicted to be dramatic. Historically it is accompanied by planet-wide outbreaks of violent storms at the latitude of the SEB.