James Webb Space Telescope Detects Fresh Ice and Chaos Terrains on Europa
New observations from the James Webb Space Telescope (JWST) reveal that patches of fresh crystalline ice on Jupiter’s moon Europa are renewed fast enough to survive heavy radiation that should destroy them in less than 15 days. According to a study published on May 28 in The Planetary Science Journal, the findings offer new insight into the hidden chemistry and dynamic interior of the icy moon’s subsurface ocean.
Subsurface Activity and Chaos Terrains
For decades, scientists pictured Europa’s frozen surface as a still, silent shell. According to Richard Cartwright, a spectroscopist at Johns Hopkins University’s Applied Physics Laboratory and lead author of the new study, the new observations reveal that the moon is a dynamic world far from frozen in time. Researchers found that the surface is porous and warm enough in certain areas to allow ice to recrystallize rapidly.
The study focused on two regions in Europa’s southern hemisphere: Tara Regio and Powys Regio. Tara Regio stands out as one of the moon’s most intriguing areas, where JWST detected crystalline ice both at the surface and deeper below. These areas feature “chaos terrains,” which are highly disrupted regions where blocks of ice appear to have broken off, drifted, and refrozen. These zones serve as potential windows into Europa’s interior, pointing to geologic activity pushing material up from beneath the thick icy shell.
Hidden Chemistry and Radiation Effects
Ujjwal Raut, program manager at the Southwest Research Institute and co-author of the study, stated that the data shows strong indications that surface materials originate from the interior, potentially from a subsurface ocean located nearly 20 miles (30 kilometers) beneath the shell. Raut and his team conducted laboratory experiments to study how water freezes on Europa under constant bombardment by charged particles from space.
Unlike Earth’s natural hexagonal ice crystal structure, intense radiation on Europa disrupts ice molecules, creating amorphous ice—a disordered, noncrystalline form. JWST’s NIRSpec instrument detected these chemical signatures across a wide range of infrared wavelengths, mapping crystalline water ice and a specific form of carbon dioxide called 13CO₂. Cartwright noted that the location exhibits strange and exciting chemistry, including strong evidence of sodium chloride—like table salt—alongside carbon dioxide and hydrogen peroxide.
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