Jupiter's bands are produced because at some latitudes, air is rising, while at others it is sinking. At any one time, there are as many as 15 major zones (where air is rising) and belts (where it is descending) that extend all around the planet. Chemicals present in Jupiter's atmosphere may well also influence its appearance from Earth.
The Great Red Spot is a distinctive hurricane-like vortex in Jupiter's southern hemisphere. Its relatively dark colour shows that we are looking fairly deep into the planet's atmosphere, below the white cloud tops. The spot is about 25,000 km (16,000 miles), in an east-west direction, and 12,000 km (7,500 miles), north to south. It is so distinctive that it can be seen quite clearly from Earth with even a small telescope. The spot is so persistent that it has been observed for 300 years. Compare this with hurricanes on Earth, that last for a few weeks at most. In fact, Earth could fit into the spot twice over.
Jupiter's Great Red Spot
