Key Takeaways
- NASA researchers estimate Europa’s ice shell to be about 18 miles (28.9 km) thick based on data from the Juno orbiter.
- The ice thickness is key to determining the moon’s potential habitability and presence of life beneath its surface.
- Two missions, NASA’s Europa Clipper and ESA’s Juice, are set to explore Europa further, with arrivals expected in 2030 and 2031, respectively.
New Insights on Europa’s Ice Shell Thickness
After years of debate, NASA researchers have determined the thickness of Europa’s ice shell, a key component in the search for extraterrestrial life. The icy surface of Europa, a moon of Jupiter, was first observed in 1979 by the Voyager 2 spacecraft. This finding was later confirmed by the Galileo mission in the 1990s, which studied Europa and other moons of Jupiter.
Since these initial discoveries, scientists have proposed two conflicting theories regarding the thickness of the ice shell: one suggesting it is less than 1 mile (1.6 kilometers) thick, while the other estimates it to span several miles. However, new measurements from NASA’s Juno orbiter, which gathered data in 2022, have provided clarity. Researchers at NASA’s Jet Propulsion Laboratory estimate the ice shell is approximately 18 miles (28.9 km) thick, correlating to the cold, rigid outer layer of pure water ice.
Steve Levin, Juno project scientist, mentioned that if there exists an inner, warmer convective layer, the total thickness could be even greater. Additionally, if the ice shell contains dissolved salt, a factor suggested by some models, the estimated thickness would reduce by about 3 miles (5 km). Understanding the structure and composition of Europa’s ice shell is crucial as it may harbor a subsurface ocean that could contain the ingredients for life.
Scott Bolton, principal investigator for Juno, noted that the thickness of the ice shell and the presence of cracks or pores are essential in evaluating Europa’s potential to support life. A thicker ice shell may pose challenges for oxygen and nutrients to reach the subsurface ocean, which could reduce the chances of finding life forms.
These findings are particularly relevant as two spacecraft are currently on their way to further investigate the Jovian system. NASA’s Europa Clipper, scheduled to orbit Jupiter and assess Europa’s habitability, is expected to arrive in 2030, followed by the European Space Agency’s Juice (JUpiter ICy moons Explorer) in 2031. The new insights regarding Europa’s ice shell were published on December 17 in the journal Nature Astronomy, marking a significant advancement in the ongoing exploration of this intriguing moon.
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