Sunday, November 28, 2010
Jupiter's Belt to Return?
The image to the left contrasts the view through Don, my 8" Newtonian, on August 2009 and September 2010, at similar parts of it's opposition cycle (imaged with a Pillips ToUCam). As you can see the distinctive southern band is now a pale and anemic band (but it's now much easier to see the Great Red Spot).
We all know that Jupiter's atmosphere is very dynamic, but for an entire band to go is ridiculous! As it happens this event has occurred several times in the past. What astronomers thing is happening is that high white clouds of ammonia ice are forming above the darker band, obscuring it from view. Then, weeks to even years later, dark material erupts from below the cloud deck and the band reforms.
Emily Lakdawalla has some great explanations and images, as well as animations, here. The Bad Astronomer has a good discussion as well.