The weather on Jupiter is changeable, as these before-and-after pictures show. The photograph on the left shows Jupiter as seen in June 2009. The photo on the right, taken on May 9, 2010, reveals that one of the planet's prominent dark cloud belts has faded away. The lightening of the South Equatorial Belt is due to atmospheric changes. Both pictures were taken by Anthony Wesley, an amateur astronomer in Australia.
Launched in 1989, the Galileo spacecraft has photographed Jupiter as well as several of the giant planet's satellites. Here's a montage that shows Jupiter's Great Red Spot and the four largest moons. From top, they are Io, Europa, Ganymede and Callisto.
Callisto is considered the most cratered celestial body in the solar system. The false-color overlay at right exaggerates the moon's surface features, including the Valhalla impact structure near the center of the disk.
Colors are enhanced in this view of Ganymede's trailing hemisphere, highlighting the moon's polar caps. The violet color indicates where small particles of frost may be scattering light on the blue end of the spectrum.
The mosaic at left shows the true colors of the cloud patterns in Jupiter's northern hemisphere. The rendition at right uses false colors to represent the height and thickness of the cloud cover.
A true-color picture captures the subtle shadings of Jupiter's Great Red Spot, a massive, long-lived storm system in the planet's thick atmosphere.
A computer-generated perspective view shows the Pwyll impact crater on Europa, an ice-covered moon of Jupiter. The heights are exaggerated, but the central peak indicates that the crater may have been modified shortly after its formation by the flow of underlying warm ice.
This image of Io, thought to be the solar system's most volcanically active world, shows the plumes of two eruptions. One plume can be seen at the very edge of the disk, the other is puffing up from the dark volcanic ring near the center of the disk.
An active volcanic eruption on Jupiter's moon Io flares in an image taken in February 2000 by the Galileo spacecraft. The dark L-shaped lava flow to the left of center marks the site of energetic eruptions in November 1999 at Tvashtar Catena, which is a chain of giant volcanic calderas. The two small bright spots at left side of image are sites where molten rock is exposed to the surface at the toes of lava flows.
The thin crust of Europa's Conamara region is criss-crossed by craters, cracks and lines - indicating that the surface ice was repeatedly disrupted. The colors, which are enhanced in this view, show where light ice crystals and dark contaminants have settled onto the surface.
In a picture taken in April 2001 by NASA's Cassini spacecraft, the moon Io looks like a marble set against the background of Jupiter. Io is the giant planet's third-largest satellite.