Europa's future ocean. Artwork of an ocean of liquid water on Europa, a moon of Jupiter, in the distant future. At the present time, Europa is covered with a thick layer of water ice. As the Sun (centre) expands towards the red giant stage towards the end of its life (in some 5 billion years), the heat may be sufficient to melt the ice on Europa, forming this ocean. An atmosphere may also develop, as the thin clouds here demonstrate. A crescent Jupiter is seen at upper right, with a crescent moon below it.