Jupiter’s icy moon Europa might be hiding a salty, liquid ocean deep beneath its surface—and new experiments suggest that its frozen crust is far more dynamic than scientists once thought.
Recent research led by Dr. Ujjwal Raut from the Southwest Research Institute supports data collected by the James Webb Space Telescope (JWST), showing that Europa’s icy surface is constantly changing.
Europa’s surface ice is made up of both crystalline and amorphous ice.
On Earth, crystalline ice forms when water freezes into neat, hexagonal patterns. But in space, ice is exposed to intense radiation.
On Europa, charged particles from Jupiter bombard the surface, disrupting the crystalline structure and turning it into amorphous ice—a more disordered form.
Until now, scientists believed that Europa had only a thin layer of amorphous ice on top, about half a millimeter deep, with crystalline ice hidden underneath.
However, this new study, based on lab experiments and telescope data, reveals that crystalline ice can also be found on the surface in some areas.
This is especially true in a region called Tara Regio, which is known as a “chaos terrain”—a jumbled area full of ridges, cracks, and strange formations.
Dr. Richard Cartwright, a spectroscopist from Johns Hopkins University and co-author of the study, said parts of Europa’s surface may be warm and porous enough to allow ice to quickly re-form into crystalline structures.
Tara Regio is particularly interesting because it shows some of the strongest evidence for table salt, carbon dioxide (CO₂), and hydrogen peroxide on the moon. These substances likely come from Europa’s interior, suggesting that materials from a subsurface ocean are making their way to the surface.
What’s even more fascinating is the type of CO₂ detected. Scientists found not only the most common form of carbon dioxide, made with carbon-12 atoms, but also a heavier version that contains carbon-13.
This rare isotope is harder to explain and adds to the evidence that the material comes from deep within Europa.
Dr. Raut’s lab experiments helped determine how quickly Europa’s ice can change structure—freezing, melting, and reforming—especially in regions with complex surface features. These insights suggest that internal geologic activity might be pushing up materials from below the icy shell, which is estimated to be around 20 miles thick.
With each new discovery, the case for an underground ocean on Europa grows stronger. That’s an exciting possibility, because where there’s water, there might also be the ingredients for life.
Scientists are eager to learn more, and future missions could bring us even closer to understanding what’s happening beneath Europa’s icy surface.
