Why Europa's hidden ocean may be more difficult to reach than scientists thought - Phys.org

What the report says

Phys.Org, citing a Rutgers University-led study published in Nature Astronomy, reported July 24 that Europa’s subsurface ocean may be less accessible from the moon’s surface than some exploration scenarios have assumed. The study, led by Rutgers planetary scientist Lujendra Ojha, used computer simulations to examine whether liquid water from Europa’s deep ocean could travel upward through cracks in its icy shell and form shallow reservoirs closer to the surface.

The researchers found that such a pathway is likely difficult. Their modeling focused on fractures known as dikes, where water might rise through ice in a process sometimes compared with cryovolcanism. According to the report, the simulations suggest that water moving through these cracks would become turbulent, rapidly lose heat to surrounding ice and potentially form frazil ice crystals that clog the route. Narrow cracks could freeze in hours, while larger pathways would require conditions the researchers considered unlikely for producing some observed surface features.

The finding matters because shallow liquid reservoirs, if detected, may not be direct samples of Europa’s deeper ocean. Phys.Org reported that they could instead result from local melting within the ice shell. That distinction is important for astrobiology, since Europa’s deep ocean is a major target in the search for potentially habitable environments beyond Earth.

The study arrives ahead of closer investigations by NASA’s Europa Clipper, launched in 2024 and expected to reach Jupiter in 2030, and the European Space Agency’s JUICE mission, expected in the Jupiter system in 2031. Those missions may help assess Europa’s ice structure, surface chemistry and possible subsurface water, but the new work suggests scientists will need caution when interpreting any shallow water they find.