James Webb Space Telescope Reveals Rapidly Renewing Ice on Europa

New observations from the James Webb Space Telescope (JWST) reveal patches of fresh crystalline ice on Europa that should be destroyed by Jupiter’s heavy radiation in less than 15 days, proving the icy moon’s surface is actively renewing itself and offering new windows into its subsurface ocean.

Beyond a Frozen Shell: Mapping Europa’s Dynamic Surface

For decades, planetary scientists pictured Europa’s icy exterior as a silent, static shell. Fresh spectral data published on May 28 in The Planetary Science Journal completely dismantles that old assumption. The James Webb Space Telescope is rewriting our understanding of Jupiter’s moon, exposing an active world where geological processes constantly rework the landscape.

On Earth, water naturally freezes into a stable, hexagonal crystalline lattice. But Europa sits deep inside Jupiter’s crushing magnetic field and radiation belts. Charged particles constantly bombard the surface, breaking down orderly molecular bonds and turning water ice into a disordered, noncrystalline state known as amorphous ice.

Yet, JWST detected prominent patches of crystalline ice right at the surface. Because Jupiter’s radiation environment should obliterate these crystalline structures in less than 15 days, something must be manufacturing and pushing fresh ice to the surface at a rapid, continuous pace.

Decoding Tara Regio and Powys Regio

The recent study zeroed in on two distinct geological zones within Europa’s southern hemisphere: Tara Regio and Powys Regio.

According to Richard Cartwright, a spectroscopist at Johns Hopkins University’s Applied Physics Laboratory and lead author of the study, parts of the surface are porous and warm enough to allow rapid ice recrystallization. The data show that these highly disrupted zones—often called “chaos terrains,” where large blocks of ice have fractured, drifted, and refrozen—are actively pumping material up from below.

The spectral signatures captured by JWST’s Near-Infrared Spectrograph (NIRSpec) instrument are remarkably complex. NIRSpec measures infrared wavelengths with exceptional sensitivity, allowing researchers to map chemical distributions across the terrain all at once.

“Our data showed strong indications that what we are seeing must be sourced from the interior, perhaps from a subsurface ocean nearly 20 miles (30 kilometers) beneath Europa’s thick icy shell,” explained Ujjwal Raut, program manager at the Southwest Research Institute and co-author of the study.

Unusual Chemistry and the Search for Habitability

The hidden chemistry uncovered by JWST goes far beyond simple water ice. Researchers examining Tara Regio identified strong spectral evidence for sodium chloride—essentially table salt—alongside carbon dioxide and hydrogen peroxide.

Photo: space.com

“In this same region […] we see a lot of other unusual things, including the best evidence for sodium chloride, like table salt, probably originating from its interior ocean,” Cartwright noted. “We also see some of the strongest evidence for CO2 and hydrogen peroxide on Europa. The chemistry in this location is really strange and exciting.”

NIRSpec’s ability to detect specific isotopic signatures, including carbon dioxide variants like ¹³CO₂, provides researchers with precise tools to track geological and chemical cycling. These compounds travel upward through the fracturing ice shell, leaving chemical fingerprints that give scientists a proxy for probing the chemistry of the global ocean hidden miles below.

As missions like NASA’s Juno continue to capture close-up imagery of the Jovian system, ground-based and space-borne spectroscopy like this establishes a critical framework. By combining laboratory simulations of radiation-damaged ice with high-resolution JWST infrared data, researchers are closing in on how surface-subsurface interactions operate on ocean worlds across the outer solar system.