Europa's Mysterious Interior (Artist's Concept)

Scientists believe that under the icy surface of Jupiter's moon Europa a saltwater ocean exists that may contain more than twice as much liquid water as all of Earth's oceans combined. This artist's concept (not to scale) depicts what Europa's internal structure could look like: an outer shell of ice, perhaps with plumes of material venting from beneath the surface; a deep, global layer of liquid water; and a rocky interior, potentially with hydrothermal vents on the seafloor.