Europa’s ice may be feeding a hidden ocean that could support life

For years, scientists have struggled to explain how life-supporting materials might move from Europa’s surface down to its ocean, which is sealed beneath a thick layer of ice. Researchers used computer simulations inspired by a geological process on Earth called crustal delamination. Their models suggest that dense ice packed with nutrients can break away from surrounding ice and slowly sink through the shell until it reaches the ocean below.

“This is a novel idea in planetary science, inspired by a well-understood idea in Earth science,” said Austin Green, lead author and postdoctoral researcher at Virginia Tech. “Most excitingly, this new idea addresses one of the longstanding habitability problems on Europa and is a good sign for the prospects of extraterrestrial life in its ocean.”

Why Europa’s Ocean Poses a Habitability Puzzle

The research was published in The Planetary Science Journal and authored by Green, who completed much of the work during his doctoral studies at WSU, along with Catherine Cooper, an associate professor of geophysics in the School of Environment and associate dean in the College of Arts and Sciences.

Europa holds more liquid water than all of Earth’s oceans combined. However, that vast ocean sits beneath an icy shell so thick it blocks sunlight entirely. Without sunlight, any life in Europa’s ocean would need alternative sources of energy and nutrients, raising long-standing questions about whether the environment could actually support living organisms.

Adding to the complexity, Europa is constantly exposed to intense radiation from Jupiter. This radiation reacts with salts and other materials on the moon’s surface, producing compounds that could serve as nutrients for microbes. While scientists know these nutrients exist on the surface, it has remained unclear how they could move downward through the ice to reach the ocean. Although Europa’s surface is geologically active due to Jupiter’s gravitational forces, most of that motion occurs sideways rather than downward, limiting direct exchange between the surface and the ocean.

Borrowing an Idea From Earth’s Geology

To tackle this problem, Green and Cooper turned to Earth for inspiration. They focused on crustal delamination, a process in which sections of Earth’s crust become compressed, chemically altered, and dense enough to detach and sink into the mantle below.

The researchers believed a similar process could occur on Europa. Certain areas of Europa’s ice shell contain high concentrations of salt, which increases the density of the ice. Previous research has also shown that impurities weaken the structure of ice crystals, making them less stable than pure ice. For delamination to occur, this weakened ice would need to break free and sink deeper into the ice shell.

How Dense Ice Could Feed Europa’s Ocean

The team proposed that heavy, salt-rich ice embedded within purer ice could slowly descend through the shell, recycling surface material and delivering nutrients to the ocean. Their computer models showed that this sinking could occur across a wide range of salt levels, as long as the surface ice experiences even modest weakening.

According to the simulations, the process could happen relatively quickly on geological timescales and repeat over long periods. That makes it a potentially steady and reliable way to transport nutrients into Europa’s ocean, improving the chances that life could survive there.

Relevance to NASA’s Europa Clipper Mission

These findings align closely with the goals of NASA’s Europa Clipper mission, which launched in 2024. The spacecraft is designed to study Europa’s ice shell, subsurface ocean, and overall habitability using a suite of scientific instruments.

The research was supported in part by the National Aeronautics and Space Administration (NASA) Grant NNX15AH91G and relied on computing resources from the Center for Institutional Research Computing at Washington State University.