Jupiter has lost a stripe

[classicman]

Jupiter has lost a stripe and scientists want to know why.

The largest planet in our solar system has been dominated by a pair of red bands or stripes, one in each of the northern and southern hemispheres.

But interplanetary detectives have a mystery on their hands.

The most recent pictures of the giant taken by amateur astronomers show the lower stripe - called the Southern Equatorial Belt - has decamped. It has left the planet’s bottom half looking a little bare.

Journalist and amateur astronomer Bob King, also known as Astro_Bob, was one of the first to note the strange phenomenon.

“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,” he told Britain’s Daily Mail.

This is not the first time it has done so while being observed, in 1973 the Pioneer space probe passed by and scientists noticed that it was missing then, too. Later, in the ’90s, it vanished temporarily.

But nobody knows why.

The planet is a giant ball of gas and liquid around 800 million kilometres miles from the Sun. Its surface is composed of dense red, brown, yellow, and white clouds arranged in light-coloured areas called zones and darker regions called belts.

The clouds are created by chemicals that have formed at different heights. The highest white clouds are made of crystals of frozen ammonia. Darker, lower clouds are created from substances that include sulphur and phosphorus. The clouds are blown into bands by 560 km/h winds caused by Jupiter's rapid rotation.

Noted Jupiter watcher Anthony Wesley, who spotted an impact spot on its surface last year, has tracked the disappearing belt from his back garden in Australia.

“It was obvious last year that it was fading. It was closely observed by anyone watching Jupiter,” he told the Planetary Society.

Wesley thinks that some kind of storm blew the ring away. With winds normally blowing at more than 500 km/h, that would be some storm.

The Australian predicts the stripe will soon begin to reassert itself. He says the first sign will be a brilliant white spot forming somewhere in the south. That will be followed by the blooming of dark blobs which will then be stretched into a new stripe.

Until it disappears once again.

Jupiter will be closest to Earth on Sept. 24, offering stargazers a good chance to see the stripeless planet.