Europa's icy surface is changing fast, hinting at ocean below, says new NASA-backed study

New lab experiments and James Webb Telescope data show Europa’s icy surface constantly changing due to heat and cosmic particles. Scientists believe this could be clear evidence of a salty liquid ocean beneath the surface.

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A new study combining data from NASA’s James Webb Space Telescope (JWST) and laboratory experiments led by Southwest Research Institute (SwRI) suggests that the icy surface of Jupiter’s moon Europa is constantly changing, possibly due to an ocean beneath.

Dr. Ujjwal Raut, a planetary scientist at SwRI, and his team conducted detailed experiments to understand the nature of Europa’s surface ice. The findings align closely with recent spectral data from JWST and strengthen the case for a dynamic, subsurface ocean nearly 30 kilometers (20 miles) beneath the icy crust.

Ice on Europa: Not all the same

Europa’s ice isn’t uniform. On Earth, ice forms a neat hexagonal structure known as crystalline ice. But Europa’s surface is constantly bombarded by high-energy particles from Jupiter’s magnetic field. These particles break down the orderly crystal structure and form amorphous ice, a more disordered form.

For years, scientists believed Europa had a thin top layer of this amorphous ice, covering crystalline ice underneath. But the new experiments and JWST data show crystalline ice is also present on the surface in several regions, especially in areas called 'chaos terrains', the rugged, broken zones where surface materials appear pushed up from below.

Why Tara Regio is special

One such area, Tara Regio, shows signs of rapid ice reformation. “We think the surface is warm and porous enough here for ice to quickly return to its crystalline form,” said Dr. Richard Cartwright, co-author and spectroscopist at Johns Hopkins University’s Applied Physics Lab.

This region also shows strong signs of salt (sodium chloride), carbon dioxide (CO₂), and hydrogen peroxide—all unusual for the moon’s surface. The type of carbon found includes both common and rare isotopes, suggesting the material comes from deep within Europa.

Clues from beneath the surface

“The chemical signatures we see, especially CO₂, are best explained by materials coming up from a subsurface ocean,” Dr. Raut explained. “These fractured zones may be pathways through which interior water and salts reach the surface.”

The study provides growing evidence that Europa’s icy shell isn’t just passively frozen but is actively shaped by heat and movement below. The presence of crystalline ice on the surface, along with compounds like salt and CO₂, could indicate that water from the ocean is interacting with the surface more than previously thought.

What this means for future missions

This discovery is especially exciting as NASA prepares for its upcoming Europa Clipper mission, which aims to explore the moon’s habitability. Understanding how and where Europa’s surface is connected to its interior will help scientists locate potential signs of life.

“Every new piece of evidence makes Europa one of the most promising places to look for life beyond Earth,” said Raut. “And now we’re seeing clearer signs that what lies beneath may be surfacing.”

-With agency inputs