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Study solves an intriguing mystery about Jupiter's icy moon

Jupiter’s icy moon, Europa, is a puzzle box of cosmic mysteries ready to be solved. Scientists use principles similar to analyzing a snowball to explore Europa’s secrets. This method is fundamental in planetary science, blending everyday experience with the quest to understand the enigmas of the universe.

Consequently, through studying Europa’s ice, researchers are revealing new details about its ocean and assessing its life-sustaining potential.

Europa’s icy surface and vast saltwater oceans make it a prime candidate for life beyond Earth. The ice shell’s thickness is crucial for understanding the moon’s geology and habitability. Until now, this key detail has remained unknown.

A breakthrough in planetary science

A team from the Department of Earth, Atmospheric, and Planetary Sciences at Purdue University, including Professor Brandon Johnson and research scientist Shigeru Wakita, has made a pivotal discovery regarding Europa’s ice shell.

The research revealed that the ice enveloping Europa is at least 20 kilometers thick. This revelation comes from a detailed study of the moon’s large impact craters, coupled with sophisticated modeling techniques to decipher the physical characteristics shaping these craters.

New details about Jupiter’s icy moon

Wakita’s insights highlight the novelty of their findings, challenging previous assumptions of a thin ice layer and suggesting a substantial barrier over the ocean. The implications of a thick ice shell bring new considerations for Europa’s dynamics. This includes the potential for convection currents that could influence its icy surface and internal ocean.

Professor Johnson’s expertise in planetary physics played a crucial role in this study. Utilizing data and imagery from the Galileo spacecraft’s 1998 mission to Europa, Johnson examined the moon’s craters to deduce aspects of its subsurface structure. This approach capitalizes on impact craters as natural probes, offering a window into the underlying layers of planetary bodies.

The significance of Europa’s ice shell

The thickness of Europa’s ice shell holds the key to understanding a myriad of processes on the moon, from plate tectonics to the potential for life.

The surface of Jupiter’s icy moon, young in geological terms, undergoes continuous transformation due to tectonic activities and convection currents. These changes contribute to the dynamic and complex nature of its ice shell. Moreover, the moon’s relatively unaged surface enhances the visibility and analysis of impact craters, offering scientists crucial insights into its subsurface realm.

Professor Johnson highlights the role of this research in seeking extraterrestrial life. The exchange between Europa’s surface and ocean closely ties to the ice shell’s traits. Grasping these processes is crucial for gauging the moon’s habitability and life’s viability in such harsh conditions.

Looking forward

The study not only enhances our understanding of Europa but also pushes the boundaries of planetary science. By combining observational data with theoretical models, scientists are inching closer to answering the age-old question of whether we are alone in the cosmos.

As we continue to explore these distant worlds, each discovery brings us one step closer to unraveling the secrets of our solar system and beyond.

More about Europa

Europa, one of Jupiter’s moons, stands out as one of the most intriguing celestial bodies in our solar system. This moon is slightly smaller than Earth’s moon and is characterized by a smooth, icy surface that makes it one of the brightest moons in the solar system. 

This bright surface is composed mainly of water ice and is crisscrossed by a complex pattern of streaks and cracks, which are thought to be caused by the tidal forces exerted by Jupiter’s strong gravity.

Subsurface ocean 

Beneath Europa’s icy crust lies a vast ocean of liquid water, estimated to be up to 100 miles deep in some places. 

The subsurface ocean is kept liquid by the intense tidal heating caused by its elliptical orbit around Jupiter. This process generates enough heat to maintain the water in liquid form, a crucial ingredient for life as we know it.

Extraterrestrial life 

The presence of a liquid ocean beneath its frozen surface makes Europa a prime candidate in the search for extraterrestrial life within our solar system. 

Scientists believe that the ocean could contain twice as much water as all of Earth’s oceans combined and that the chemical interactions between the ocean and the rocky mantle below might create the conditions necessary for life.


Europa’s atmosphere is thin and composed primarily of oxygen, but it’s not breathable for humans. The oxygen is likely generated when water molecules are split into hydrogen and oxygen through the process of radiolysis, driven by Jupiter’s intense radiation belts. 

The hydrogen escapes into space, while the oxygen remains, contributing to the moon’s thin atmosphere.


NASA and the European Space Agency (ESA) have shown a keen interest in Europa and have plans to explore it further. NASA’s Europa Clipper mission, slated for launch in the 2020s, aims to conduct detailed reconnaissance of Europa’s ice shell and subsurface ocean by performing multiple flybys of the moon. 

Meanwhile, the ESA’s Jupiter Icy Moons Explorer (JUICE) mission, also launching in the 2020s, will study not only Europa but Ganymede and Callisto as well.

The study is published in the journal Science Advances.


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