Europa’s ocean may be vast and mysterious—but beneath the ice, it could be eerily quiet and lifeless.
Jupiter is surrounded by nearly 100 known moons, but Europa stands apart. Covered in ice and believed to hide a massive ocean of salty liquid water beneath its surface, the moon has been a prime target in the search for life beyond Earth. For years, scientists have debated whether this hidden ocean could provide the right environment for living organisms, making Europa one of the most compelling places to explore in the solar system.
New Research Challenges the Idea of a Living Seafloor
A new study led by Paul Byrne, an associate professor of Earth, environmental, and planetary sciences, raises doubts about whether Europa’s ocean could support life at its base. By analyzing the moon’s size, the composition of its rocky interior, and the gravitational pull it experiences from Jupiter, the research team found little evidence that Europa has the kind of active geology thought to be essential for life. Their results suggest the moon lacks tectonic movement, hydrothermal vents, and other forms of underwater activity that could supply energy to living systems.
“If we could explore that ocean with a remote-control submarine, we predict we wouldn’t see any new fractures, active volcanoes, or plumes of hot water on the seafloor,” Byrne said. “Geologically, there’s not a lot happening down there. Everything would be quiet.” On a frozen world like Europa, he added, a still and inactive seafloor could mean the ocean is lifeless.
Study Details and Research Team
The findings were published in Nature Communications. The study’s co-authors include Professor Philip Skemer, associate chair of the Department of Earth, Environmental, and Planetary Sciences; Professor Jeffrey Catalano; Douglas Wiens, the Robert S. Brookings Distinguished Professor; and graduate student Henry Dawson. All are affiliated with the department, and Byrne, Skemer, Catalano, Wiens, and Dawson are also members of the McDonnell Center for the Space Sciences.
Why Europa’s Seafloor Matters
For Byrne, Europa’s mystery goes beyond the question of biology. “I’m really interested to know what that seafloor looks like,” he said. “For all of the talk about the ocean itself, there has been little discussion about the seafloor.”
Because direct exploration is not yet possible, the researchers relied on existing data about Europa and comparisons with Earth, the Moon, and other planetary bodies to draw their conclusions.
What Lies Beneath Europa’s Ice
Europa’s icy outer shell is estimated to be 15 to 25 km thick, with an ocean beneath it that likely spans the entire moon and reaches depths of up to 100 km. Although Europa is slightly smaller than Earth’s Moon, scientists believe it contains far more water than our planet.
Below the ocean sits a rocky core similar in structure to Earth’s. However, unlike Earth’s still-hot interior, Europa’s core is thought to have cooled long ago. Byrne and his colleagues calculated that any internal heat would have dissipated billions of years in the past.
Jupiter’s Gravity and the Limits of Tidal Heating
The team also examined the effects of Jupiter’s gravity, which can generate heat inside a moon through tidal forces. This process is dramatically visible on Io, Jupiter’s innermost large moon. Io experiences intense tidal stretching due to its unstable orbit, making it the most volcanically active body in the solar system.
Europa’s situation is different. Its orbit is more stable and farther from Jupiter, which reduces the strength of tidal forces acting on its interior. As a result, the gravitational energy available to drive geological activity is much weaker, Byrne explained.
“Europa likely has some tidal heating, which is why it’s not completely frozen,” Byrne said. “And it may have had a lot more heating in the distant past. But we don’t see any volcanoes shooting out of the ice today like we see on Io, and our calculations suggest that the tides aren’t strong enough to drive any sort of significant geologic activity at the seafloor.”
What This Means for Life Today
According to Byrne, the lack of energy at Europa’s seafloor makes the presence of modern life unlikely. “The energy just doesn’t seem to be there to support life, at least today,” he said.
Looking Ahead to Future Exploration
Despite these findings, Byrne remains enthusiastic about future missions to Europa, particularly NASA’s Europa Clipper spacecraft, which is scheduled to fly past the moon in the spring of 2031. That mission — conceived and championed in part by Bill McKinnon, the Clark Way Harrison Distinguished Professor in Arts & Sciences and interim director of the McDonnell Center for the Space Sciences — will capture detailed images of Europa’s surface and collect improved measurements of its ice shell and ocean. “Those measurements should answer a lot of questions and give us more certainty,” Byrne said.
Why the Search Still Matters
Even if future studies show that Europa’s ocean is lifeless today, Byrne sees value in the exploration. “I’m not upset if we don’t find life on this particular moon,” he said. “I’m confident that there is life out there somewhere, even if it’s 100 light-years away. That’s why we explore—to see what’s out there.”
Reference: “Little to no active faulting likely at Europa’s seafloor today” by Paul K. Byrne, Henry G. Dawson, Christian Klimczak, Paul V. Regensburger, Kelsey T. Crane, Jeffrey G. Catalano, Catherine M. Elder, Bradford J. Foley, Christopher R. German, Austin P. Green, Douglas J. Hemingway, Mohit Melwani Daswani, Mark P. Panning, Noah Randolph-Flagg, Barbara Sherwood Lollar, Philip Skemer, Steven D. Vance and Douglas A. Wiens, 6 January 2026, Nature Communications.
DOI: 10.1038/s41467-025-67151-3
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