Amateur astronomers are being urged to monitor giant planet Jupiter after major disturbances were seen erupting in two regions of its northern hemisphere. 

An image of Jupiter and largest moon Ganymede taken by Anthony Wesley on July 8.

The outbreaks occurred in zones called the North Equatorial Belt (NEB) and North Temperate Belt (NTB) which had both faded noticeably last year. The NEB had become extremely narrow and lost any major features along its southern edge, a state not seen for around 100 years.

John Rogers, Director of the British Astronomical Association’s Jupiter Section, reported that the NEB outbreak began on March 8 with a bright “rift” that appeared and began generating dark, slow-moving formations along the NEB’s edge.

It seemed this might indicate the start of a major revival in the belt. It was followed by an outbreak in the NTB that was first noticed on April 19 with a very bright and a very dark spot on the belt’s edge. Rogers suggested both events would be spectacular and would help understanding of the patterns of activity in Jupiter’s atmosphere.

Unfortunately all this renewed activity began just a few weeks before Jupiter disappeared behind the Sun. Observers had to wait patiently for its return in the morning sky a few weeks later at the start of a new apparition.

Now that amateur astronomers have been able to check up on Jupiter again, and take images of the planet, it is clear that the eruptions have continued. Rogers reported in a BAA Bulletin: “These images provide strong evidence that a NTBs super-fast outbreak has indeed occurred, and that a NEB Revival is probably underway.”

Jupiter’s belts indicated on an image taken by the Cassini space probe on its way to Saturn

Christopher Go, a leading CCD observer in the Philippines, said on his website: “Jupiter looks very strange! The NTB is dark but the NEB looks chaotic but no distinct belt.”

Our picture was taken by one of the world’s leading CCD imagers of the planets, Australian Anthony Wesley, from Murrumbateman, near Canberra, New South Wales. Anthony, whose previous achievement include capturing an asteroid impact on Jupiter and a storm on Saturn, remarked that there has also been a fading in the Great Red Spot, the giant storm on Jupiter that has been raging for hudreds of years.

Wesley told Skymania: “Jupiter is very interesting this year – the equatorial belt is most unusual, and the GRS has faded a lot. The violent NEB activity has ringed the north in bright colours. What does it all mean? Jupiter has shown us a different face every year for the last 10 years at least, I guess this is more of the same. :-)”