Jupiter loses a stripe

[Lord of the Abyss]

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A giant cloud belt in the southern half of Jupiter has apparently disappeared according to new photos of the planet taken by amateur astronomers.

The new Jupiter photos, taken May 9 by Australian astronomer Anthony Wesley, reveal that the huge reddish band of clouds that make up the planet's Southern Equatorial Belt has faded from view.

Jupiter's trademark Great Red Spot, a massive storm that could fit two Earths inside, is typically found along the edges of the planet's Southern Equatorial Belt (SEB). When the southern cloud belt fades from view, the Great Red Spot stands out along with Jupiter's Northern Equatorial Belt of clouds in telescope views.

"It was evident to Jupiter watchers late last year that the planet was going into one of these SEB fading cycles, but then it was lost behind the sun for several months and naturally everyone who follows these things was eager to take images as soon as possible after its re-emergence in March," Wesley told SPACE.com in an e-mail.

"As it moves away from the sun (from our point of view) it will be possible to capture even better images and perhaps we will be watching later this year or next year when the SEB revival takes place. The timing of this revival is not known, but historically this is a very dynamic event with planet-wide outbreaks of violent storms around the SEB latitude and eventually clearing away the obscuring clouds to reveal the dark SEB once more," he added.

Wesley's photos were also released by The Planetary Society in California, which added that Jupiter's Southern Equatorial Belt tends to fade from view about every three to 15 years.

"Jupiter with only one belt is almost like seeing Saturn when its rings are edge-on and invisible for a time -- it just doesn't look right," wrote skywatcher Bob King of Duluth, Minn., in a May 10 entry of his blog "Astro Bob" while discussing Wesleyan's surprising Jupiter views.

Jupiter is currently shining very bright in the eastern sky before sunrise.

Wesley is a veteran Jupiter watcher and posted the new shots on his website. It was he who first spotted a dark blemish on the planet in July 2009 that pointed to an impact on Jupiter, most likely from a comet. Wesley also spotted a giant blizzard on Saturn that is currently raging.

"Jupiter is a joy to observe and image, its dynamic atmosphere and brightly colored clouds mean that every view is different to the last even from one day to the next, and driven by the internal heat from deep inside the atmosphere you can be sure there is always something violent and interesting going on," Wesley said.

Changes in Jupiter's weather are not uncommon.

Last year, astronomers announced that Jupiter's Great Red Spot – which has raged for at least 300 years – appeared to be shrinking. In 2008, other red spot-like storms (smaller than Great Red) showed changes as well, while activity in the Southern Equatorial Belt also appeared to slow down.

Jupiter is the largest planet in our solar system and no stranger to weird weather.

Earlier this year, astronomers announced that the gas giant likely has helium rain showers from time to time. Jupiter has also tended to grow a variety of new storms, or spots, with some even changing color between white and red during dramatic climate changes on the gas giant.

Before and after pics here. It does look kind of funny.

[Temujin]

Its them damn monoliths I tell ya!

Seriously, its not just the stripe, the bands in the upper hemisphere have thickened significantly as well. I'm also assuming the Great Red Spot is simply on the other side of the planet, but without it in that comparison shot the contrasting elements stand out that much more. Whatever is causing it, its certainly some serious atmospheric disturbance.

[Molyneux]

Looks a bit interesting...
For that matter, it probably pays to remember that the Red Spot itself will probably fade at some point, though probably not within our lifetimes.

[Temujin]

well, I guess this ain't the first time it's happened, but oddly I don't ever remember hearing about it.

Jupiter loses a stripe

* 21:49 11 May 2010 by David Shiga
* For similar stories, visit the Solar System Topic Guide

Jupiter has lost one of its prominent stripes, leaving its southern half looking unusually blank. Scientists are not sure what triggered the disappearance of the band.

Jupiter's appearance is usually dominated by two dark bands in its atmosphere – one in the northern hemisphere and one in the southern hemisphere.

But recent images taken by amateur astronomers show that the southern band – called the south equatorial belt – has disappeared.

The band was present at the end of 2009, right before Jupiter moved too close to the sun in the sky to be observed from Earth. When the planet emerged from the sun's glare again in early April, its south equatorial belt was nowhere to be seen.
No cover

This is not the first time the south equatorial belt has disappeared. It was absent in 1973 when NASA's Pioneer 10 spacecraft took the first closeup images of the planet and also temporarily vanished in the early 1990s.

The bands may normally appear dark simply because pale, high-altitude clouds prevalent in other regions of the planet are missing there, revealing darker clouds below, says Glenn Orton of the Jet Propulsion Laboratory in Pasadena, California. "You're looking into different layers of the cloud structures of the planet," he told New Scientist.

According to this theory, the south equatorial belt disappears when whitish clouds form on top of it, blocking our view of the darker clouds. But it is not clear what causes these whitish clouds to form in the south equatorial belt at some times and not others, Orton says.

The disappearance of the belt comes at a time of widespread – but mysterious – change on Jupiter, which has seen changes to the colour of other bands and spots in its atmosphere. "There has been a lot going on," Orton says