Bad News for Alien Hunters As Study Suggests Europa Is Geologically Quiet

A new study suggests the moon's seafloor might be geologically dead.

Europa has long been the darling of the search for life beyond Earth. The reason is simple: beneath its cracked, icy shell sits a global ocean of salty water, with salt and water being two vital elements for life as we know it. But a new study suggests the seafloor beneath that ocean may be far less lively than we hoped.

The research, published in Nature Communications, argues that Europa probably lacks the kind of ongoing tectonic motion and seafloor volcanism that helped power hydrothermal vents and sustain deep-ocean ecosystems as on Earth.

“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,” said Paul Byrne, a researcher from the Department of Earth, Environmental and Planetary Sciences at Washington University in St. Louis and first-author. “Geologically, there’s not a lot happening down there. Everything would be quiet.”

The numbers behind the quiet

Europa is constantly squeezed and stretched by Jupiter’s massive gravity. This process, called tidal flexing, generates enough heat to keep the moon from freezing solid. But the big question has always been: Is that flexing strong enough to crack Europa’s rocky seafloor the way Earth’s tectonics refresh our ocean crust?

Byrne’s team created a model and ran the numbers. They calculated the stress caused by tidal flexing, long-term cooling, and the moon’s internal contraction. In every scenario, the math pointed to the same conclusion: modern-day forces are just too weak to crack the rock.

The study estimates that the stress on the seafloor tops out at roughly 54 kilopascals. To put that in perspective, that is only a fraction of the strength required to break rock at shallow depths. At kilometer down, it’s nowhere near enough.

Even when the authors accounted for “rock fatigue,” the idea that repeated stretching over millions of years might weaken the crust, the stress levels remained too low to trigger deep faults.

The takeaway is blunt: Expect “little to no active faulting.”

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This means there are likely no pathways for seawater to circulate through hot, fresh rock. Without that interaction, it is difficult to sustain the chemical energy sources that microbes love to exploit.

“The energy just doesn’t seem to be there to support life, at least today,” Byrne said.

Quiet, but not closed for business

However, a quiet seafloor doesn’t necessarily mean a dead one.

“What our work at WHOI has shown is that so long as Europa’s seafloor has been geologically active in the past,” said Chris German, Woods Hole Oceanographic Institution (WHOI) senior scientist and co-author, “It could still have more than enough capacity to host lower-temperature forms of fluid flow…that could underpin a geothermally-driven food chain.”

German points out that on Earth, massive hydrothermal systems can exist far away from active volcanoes. These systems circulate cooler fluids (often under 100°C / 212°F) through the crust over long periods.

If Europa isn’t cracking and popping with volcanic fireworks today, the best bet for habitability might shift toward this “slow chemistry”—long-lived circulation or even energy derived from radioactive decay in the rocks.

A reality check arrives in 2031

This is a modelling study, but the findings are crucial for NASA’s Investigating Ocean Worlds project, a massive effort to understand how organic compounds form in alien oceans.

“One of the core components…will be an investigation of fluids circulating at lower temperatures beneath the seafloor of an Ocean World like Europa,” German said.

The clock is also ticking because Europa Clipper is on the way. NASA’s official mission timeline places the spacecraft’s first Europa flyby in spring 2031. Clipper won’t drill to the seafloor, but it can sharpen key unknowns such as ice thickness, ocean properties, potential plume chemistry and indirect hints about water–rock interaction.

Byrne welcomes the chance for Europa to argue back.

“Those measurements should answer a lot of questions and give us more certainty.”