Photograph Description

Jupiter imaged by NASA’s Cassini spacecraft. Jupiter’s largest moon Ganymede (lower centre) is also seen. Jupiter is the largest planet in the solar system. Its outer layer is composed of the gases hydrogen and helium, with tiny amounts of water, carbon dioxide, methane, and other simple molecules. High-speed winds in the outer layer are confined to wide bands which encircle the planet. Chemical and temperature variations between the bands produce the colour differences seen: light bands are known as zones, whilst dark bands are known as belts. This image was taken as Cassini passed Jupiter on its way to Saturn. (Photo by Science Photo Library)