So-called “brown barges” are cyclonic storms in Jupiter’s atmosphere that are typically found in the giant planet’s relatively dark North Equatorial Belt but they are occasionally spotted om the South Equatorial Belt as well. The storms are difficult to detect visually because they tend to blend in with the surrounding areas. But occasionally, the darker material in the belt recedes and brown barges become easier to see against the lighter background. This image, capturing a brown barge in the South Equatorial Belt, was captured by NASA’s Juno Jupiter orbiter on 6 September as the probe made its 15th close flyby at a distance of 11,950 kilometres (7,425 miles) from Jupiter’s cloudtops. The color-enhanced JunoCam image was processed by citizen-scientist Kevin M. Gill.
In the small hours of Friday, 16 October, innermost planet Mercury reaches its greatest westerly elongation from the Sun. For those of you in the UK with a flat, unobscured eastern horizon and willing to get up an hour before sunrise, the next few days provide your best opportunity to see Mercury from the Northern Hemisphere during 2015.
A team of scientists has documented atmospheric changes on Io, Jupiter’s volcanically active satellite, as the giant planet casts its shadow over the moon during daily eclipses. Io’s thin atmosphere collapses as the sulfur dioxide gas emitted from volcanoes freezes when shaded by Jupiter. The atmosphere reforms when Io moves out of eclipse and the ice sublimates.