The gas giant planets. Artist's view.

The giant planets and beyond

Beyond the orbit of Mars and the asteroid belt lie the gaseous planets Jupiter, Saturn, Uranus and Neptune. Pluto is now recognized as the largest of a family of dwarf planets that lie beyond Neptune’s orbit.

Today only Jupiter and Saturn have been explored in any depth. Indeed new technologies are needed to travel to the other giant planets in the far-flung regions of the Solar System.

It is highly improbable that forms of life exist on such inhospitable planets. However, a presence of water or methane in liquid form as indicated on some of Jupiter and Saturn’s moons, Europa, Titan and Enceladus, would provide suitable conditions for biological activity.