A great mystery to be solved

Where is Sherlock Holmes when you need him? There is a great mystery to be solved. In the past few weeks, astronomers have discovered that the South Equatorial Belt on Jupiter is missing.

The equatorial belts are two wide, brownish bands composed of ammonia ice, sulfur and a little phosphorus thrown in and are measured at 108F degrees below zero.

Some astronomers say the belts are not belts at all, but are gaps in the upper cloud layers showing the brownish colored cloud layers that are below. They are twice the width of 8,000-mile wide Earth and extend completely around the planet.

Just as one would associate rings with the planet Saturn, the equatorial belts are a signature item on Jupiter.

Some indication that the belt might be fading was noted last year before Jupiter went around to the far side of the sun as viewed from Earth.

Australian astrophotographer Anthony Wesley posted the first photographs of the missing belt earlier this year. He is quoted in "Science News" as saying, "I noticed the belt fading late last year, but I certainly didn't expect to see it completely disappear."

Wesley is the astronomer who photographed a large dark spot on Jupiter last summer indicating that an asteroid or comet had smashed into Jupiter's cloud tops.

Planetary scientist Glenn Orton of NASA's Jet Propulsion Laboratory says, "It's possible that some ammonia cirrus has formed on top of the belt hiding it from view." Ammonia cirrus clouds form when changes in weather patterns bring up ammonia-rich material into the cloud zone above the belt.

There is a similar phenomenon on Earth which happens when water ice crystals form high in the atmosphere. The crystals make a milky-white cloud layer which dims, but does not block sunlight.

One curious note is that while the dark band is missing, the Great Red Spot, which boarders the band, is not. The spot was noted by Galileo when he first turned a telescope on our planetary neighbor 400 years ago.

The spot is a vast and violent hurricane or tornado-like storm system with winds measuring in the hundreds of miles per hour.

Apparently this is not the first time the band has gone missing. The most recent occurrence was in 2007 and before that in 1993, 1989-90, and 1973-75.

Jupiter can be seen now in the early morning hours in the east before sunrise. A good time is about 4 to 4:30 a.m. local time.

The cloud bands can be seen, with some difficulty, in my 10 x 50 binoculars if you examine the planet carefully. They can also be seen using a small telescope.

As Holmes would say, "Come Watson, the games afoot!"

SKY WATCH: Full moon tonight, May 27, which will blot out most early evening viewing possibilities. Venus is still holding strong in the west after sunset. Mars can be found between Cancer and Leo and is inching closer to Regulus, the brightest star in Leo, each evening. By the first week in June, the reddish planet will be right on top of the star. Saturn is farther on upward between the tail of Leo and the right end of Virgo.

Now is also a good time to locate another outer gas-giant planet, the planet Uranus. It is well within the field of view in a pair of binoculars located about one degree to Jupiter's left. There are no other stars in the area for which the planet can be mistaken.

NEXT TIME: Stay tuned, fellow star gazers: there is good news for anyone who would like to learn more about the night sky. More later. Along with more astronomical blathering.