Europa’s hidden ocean may be much harder to reach than scientists once thought. New research led by a Rutgers University scientist suggests that liquid water from the subsurface ocean of Jupiter’s icy moon may struggle to travel through cracks in the ice shell and reach shallow reservoirs near the surface.
Artist’s concept of Europa’s subsurface ocean beneath its icy shell. Image credit: NASA / JPL-Caltech.
Jupiter’s moon Europa is one of the leading places in the Solar System to search for life beyond Earth. Beneath its frozen exterior lies a global ocean that may contain the chemical ingredients and energy needed to support life.
However, new research indicates that accessing this ocean — or finding water connected to it close to Europa’s surface — could be more difficult than previously believed.
“Numerous icy moons, including Europa, possess subsurface oceans beneath their icy exteriors,” said Rutgers University researcher Lujendra Ojha, who conducted the study with scientists from Johns Hopkins University and Dartmouth College.
“Liquid water from Europa’s deep ocean has been proposed to rise through dykes and form shallow sills.”
“These reservoirs could create temporary habitable environments and may be connected to some of the surface features observed on Europa.”
“However, whether dykes can transport enough water from Europa’s deep ocean to create these shallow reservoirs remains poorly understood.”
To investigate the process, the researchers used computer simulations to model how liquid water might move through fractures in Europa’s icy shell. These shallow reservoirs would be easier for future spacecraft to detect or sample than the main ocean, which may lie tens of kilometers below the surface.
“The mystery we wanted to solve was whether this journey is actually possible,” Dr. Ojha said.
“Can liquid water rise from Europa’s deep ocean toward the surface without freezing along the way?”
The simulations showed that water moving through fractures in Europa’s ice would likely flow turbulently rather than smoothly. As the water swirls against the cold walls of the cracks, it rapidly loses heat.
This cooling may cause the water to fall below its normal freezing point while remaining liquid. Under these conditions, tiny ice crystals known as frazil ice can form and block the fracture.
According to the simulations, narrow fractures could freeze shut within only a few hours. Wider cracks would need to be unrealistically long — or occur in extremely large numbers — to transport enough water upward to explain certain features on Europa’s surface.
The findings challenge comparisons between Europa’s possible cryovolcanic activity and volcanic processes on Earth.
Cryovolcanism involves the movement of water, ice and other volatile materials rather than molten rock. Although it is sometimes compared with terrestrial volcanism, the physical processes are very different because liquid water and ice do not behave like lava.
“Ice and liquid water are fundamentally different from lava and the volcanoes that we see here on Earth,” Dr. Ojha said.
“I think there’s some fundamental physics that is missing here, and so I wanted to explore that.”
The results could affect how scientists interpret evidence of water beneath Europa’s surface. If shallow pockets of liquid water exist, they may not be directly connected to the moon’s deep ocean. Instead, they could form locally when heat causes portions of Europa’s ice shell to melt.
This possibility would make it more difficult to use shallow water as a direct indicator of the deep ocean’s chemistry, composition and habitability.
“Our work suggests that Europa’s ice shell may be a stronger barrier between the ocean and the surface than previously assumed,” Dr. Ojha said.
“This helps future missions interpret what they find and better understand where to search for signs of habitability on Europa.”
The study appears in the journal Nature Astronomy.
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L. Ojha et al. Limited direct fluid exchange between the deep subsurface ocean and the shallow subsurface environment of Europa. Nat Astron, published online July 23, 2026; doi: 10.1038/s41550-026-02918-2
Source: www.sci.news