New Study Undermines Hopes for Life on Europa

In what feels like a rapid succession of blows, after last month’s post questioning Titan’s status as an ocean world, a new study now suggests that Europa lacks the internal energy required to remain geologically active, with implications for other ocean worlds.

For decades, Europa has occupied one of the most prominent places in the scientific imagination. Many have wondered whether the moon has a geologically active seafloor hosting hydrothermal vents that, on Earth, sustain entire ecosystems flourishing in absolute darkness. If there are places beyond Earth that could host life, Europa appeared to be one of them. But the new study, published here and led by planetary scientist Paul Byrne, offers a strikingly different view. Drawing on improved modelling of Europa’s interior and a reassessment of the forces acting on its rocky seafloor, the research argues that the moon may be far less geologically active than previously believed, perhaps even too quiet to sustain the chemical energy life would require.

Europa’s allure has always rested on a simple chain of reasoning. Beneath its 15–25 km shell of ice lies a global ocean roughly 100 km deep (with more water than all of Earth’s oceans combined). Importantly, this ocean is adjacent to a rocky mantle. The thinking goes that the tidal forces derived from Europa's orbit around Jupiter continually flex the moon’s interior, keeping its subsurface ocean from freezing and driving ongoing geological activity.

But Byrne’s study found that the story is not so simple. The new modelling shows that Europa’s rocky seafloor is far stronger than previously assumed. Even under the moon’s tidal flexing, the stresses are insufficient to fracture the crust at the depths required to generate hydrothermal activity. The eccentricity needed to drive such faulting (0.441) is orders of magnitude higher than Europa’s actual orbital eccentricity (0.009). In other words, the forces simply aren’t there. Even processes like serpentinisation, where water infiltrates rock and triggers heat‑producing chemical reactions, appear unable to generate the necessary geological activity. The result is a seafloor that is, in Byrne’s words, “quiet.” No new fractures. No volcanic outgassing. No plumes of hot, mineral‑rich water. And without those energy sources, Europa’s ocean may be chemically stagnant.

For years, the potential detection by the Hubble Space Telescope of water plumes erupting from Europa seemed to point to the presence of an energy-rich ocean, similar to one under the iceshell of Enceladus, Saturn's moon. But more recent analyses suggest a different origin: pockets of water trapped within the ice shell itself, heated by tidal flexing and periodically venting into space. These plumes, then, may tell us nothing about the ocean below.

If all this is rather crushing for all those, yours truly included, who have considered Europa as the archetype of a habitable ocean world, the outlook worsens still as the implications ripple far beyond Europa itself. The study suggests that while subsurface oceans may be common, habitable subsurface oceans may be rare. Indeed, tidal heating alone may not be enough, and the right combination of interior structure, orbital dynamics, and long‑term energy sources may be far more constrained than we imagined.

This reframes our expectations about habitable environments both within our Solar System and farther afield. New data is required, and with NASA’s Europa Clipper and ESA’s JUICE now en route, these spacecraft will either confirm the moon's habitability or reveal its absence. As with Titan, the story of Europa is evolving. And that, too, is progress.

And as always, onwards and upwards.