Scientists strongly believe that Europa - Jupiter's moon - has a salty ocean hiding beneath its icy shell. After modeling the ability of this proposed ocean to produce hydrogen and oxygen without the help of volcanic activity, a team of NASA scientists suggests that its salt liquid interior might have the right balance of chemicals to harbor life.
"We're studying an alien ocean using methods developed to understand the movement of energy and nutrients in Earth's own systems," said Steve Vance, a planetary scientist at NASA's Jet Propulsion Laboratory (JPL) and lead author of the study. "The cycling of oxygen and hydrogen in Europa's ocean will be a major driver for Europa's ocean chemistry and any life there, just as it is on Earth."
Vance and his team believe that Europa's interior is much more similar to Earth than we previously believed. They believe that interactions between rocks and Europa's ocean water create hydrogen through the process of serpentinization. In addition, this ocean may make its way as deep as 15 miles into Europa's interior.
Oxygen is likely obtained from above the surface through the splitting of water molecules by radiation from Jupiter. After these molecules split on Europa's cold surface, the team believes that the resulting oxidants are thrown into the ocean and subsequently react with hydrogen.
"The oxidants from the ice are like the positive terminal of a battery, and the chemicals from the seafloor, called reductants, are like the negative terminal," said Kevin Hand, a planetary scientist at JPL and co-author of the study. "Whether or not life and biological processes complete the circuit is part of what motivates our exploration of Europa."
Jupiter's other moon, Io, is the most volcanically active body in the solar system due to the heat created by the effects of Jupiter's gravity. However, scientists have also considered the possibility that Europa possesses volcanic activity as well as hydrothermal vents that allow the passage of hot water from the sea floor.
The current data suggests that even without volcanic activity and hydrothermal vents, it is possible that Europa could create mineral-rich hot water and other life-sustaining qualities that are seen in Earth's ocean.
The findings were published in the May 17 issue of the Geophysical Research Letters.
