For many years, Europa, one of Jupiter’s Galilean moons, is strongly assumed to hide an active deep salty ocean beneath its icy surface. Now, a new study from NASA’s Jet Propulsion Laboratory (JPL) suggests that this icy moon consists of the necessary life-sustaining chemical balance despite lacking volcanic hydrothermal activity.

The study, published on May 17 in Geophysical Research Letters, states that Europa’s oxygen production is 10 times higher than its hydrogen production, a scale similar to that of Earth’s, indicating its energy available for life. JPL scientists also believe that other oxidants like oxygen react with hydrogen to produce Europa’s Earth-like chemical balance.

“The oxidants from the ice are like the positive terminal of a battery, and the chemicals from the sea floor, called reductants, are like the negative terminal,” says the study’s co-author Kevin Hand, a planetary scientist at JPL. “Whether or not life and biological processes complete the circuit is part of what motivates our exploration of Europa.”


An artist’s impression shows Jupiter and its moon Europa. Credit: NASA, ESA, and M. Kornmesser

Other experts previously assumed that Europa has volcanic activity and hydrothermal vents that allow the production of mineral-rich hot water from the sea floor to be exposed to the surface, which is crucial to creating a habitable environment. The process would be impossible if the Galilean moon consists of a rocky interior that is too strong for the water to break through, making the ocean too acidic and inhabitable.

However, since Europa’s surface is cold, it can easily fracture and open up to expose the hydrogen to the surface to react and balance the oxidants in a ratio, resembling Earth’s oceans. Nevertheless, the scientists state that further investigations are still needed.

As of now, NASA is planning another mission to explore Jupiter’s moon and conduct further analysis that can reveal more insights about its capability of sustaining life. The spacecraft to be used would take high-resolution photos, identify Europa’s surface and atmosphere composition as well as explore the moon’s interior, ocean, and ice shell.