NASA Reveals New Thickness Estimate for Europa’s Ice Shell

NASA has updated its estimate of the ice shell surrounding Europa, one of Jupiter’s 95 moons, revealing that this layer is approximately **18 miles** (about **29 kilometers**) thick in certain areas. This new measurement stems from data collected during a flyby of the Juno spacecraft on **September 29, 2022**. The findings may enhance our understanding of Europa’s potential to support life by informing scientists about the characteristics of its icy covering.

During the flyby, Juno came within roughly **220 miles** (or **360 kilometers**) of Europa’s surface, utilizing its Microwave Radiometer (MWR) to gather data from around **50%** of the moon’s surface. The ice layer’s thickness is particularly significant as it relates to the cold, rigid, conductive outer layer of a pure water ice shell. According to **Steve Levin**, Juno project scientist at NASA’s Jet Propulsion Laboratory (JPL), the thickness could be greater if an inner convective layer exists beneath the ice.

Research indicates that if this inner layer is slightly warmer, the total thickness of the ice shell could increase. Interestingly, if the ice contains dissolved salts, as some models suggest, the overall thickness could be reduced by approximately **3 miles** (or **4.8 kilometers**).

Understanding Europa’s Features

The new measurements include the identification of shallow ice features, termed “scatterers,” which comprise cracks, pores, and voids near the surface. These features scatter the microwaves emitted by the MWR, providing insights into the ice’s composition. The researchers speculate that these scatterers are relatively small, measuring just a few inches in diameter.

The findings imply that oxygen and nutrients would need to travel a longer distance between the moon’s surface and its potential ocean beneath. This distance may impact how life could exist there. As **Scott Bolton**, principal investigator of Juno at the Southwest Research Institute, noted, understanding the thickness of the ice shell and the presence of these features is crucial to unraveling the complex puzzle of Europa’s habitability.

Future Implications for Exploration

The study, co-authored by Levin and Bolton, was published in **December** in the journal **Nature Astronomy**. It provides vital context for future missions, including NASA’s upcoming **Europa Clipper** and the **European Space Agency’s** **JUICE** (JUpiter ICy moons Explorer) spacecraft, both of which are en route to the Jovian system.

With every new data point, scientists are one step closer to uncovering the secrets of Europa. Understanding its icy crust and underlying ocean may eventually reveal whether life has ever existed on this intriguing moon and if conditions remain suitable for life today. The ongoing research signifies a pivotal moment in planetary science and our quest to find life beyond Earth.