Cosmic rays may be sufficient to nourish life residing underground on planets and moons within our solar system, according to new research from NYU Abu Dhabi that broadens the search for extraterrestrial life beyond the traditional “Goldilocks Zone.”
High-energy ionizing radiation from cosmic rays is typically harmful to life and can cause DNA damage. However, here on Earth, we are shielded from most of these rays by our planet’s atmosphere. The new research paints a different picture—one in which cosmic rays may not only be harmless in certain environments but could actually support life.
A New View of Life
The research was led by Dimitra Atri of the NYU Abu Dhabi Center for Astrophysics and Space Science’s (CASS) Space Exploration Laboratory. Challenging the traditional view that sunlight or volcanic heat are necessary for life, Atri’s team investigated what might happen when cosmic rays encounter underground liquid water or water ice.
Their findings revealed that cosmic rays can break down water molecules, releasing electrons. In a process reminiscent of photosynthesis, certain Earth-based bacteria have been observed consuming these electrons as an energy source through a mechanism known as radiolysis. Even in dark, cold environments completely devoid of sunlight, radiolysis has enabled bacteria to survive beneath Earth’s surface—and it may do the same elsewhere in the solar system.
Simulating Energy Potential Across the Solar System
Building on this knowledge, Atri’s team conducted simulations to estimate the energy potential of cosmic-ray interactions on several planetary bodies. The researchers focused on Mars, Saturn’s moon Enceladus, and Jupiter’s moon Europa—each of which is thought to harbor subsurface water and is considered a potential candidate for extraterrestrial life. The results suggested that Enceladus offered the most favorable conditions for radiolysis-supported life, followed by Mars, with Europa ranking third.
“This discovery changes the way we think about where life might exist,” said Atri. “Instead of looking only for warm planets with sunlight, we can now consider places that are cold and dark, as long as they have some water beneath the surface and are exposed to cosmic rays. Life might be able to survive in more places than we ever imagined.”
A New Indicator in the Search for Extraterrestrial Life
Astrobiologists have long focused on the “Goldilocks Zone,” the region around a star where a planet is neither too hot nor too cold to support liquid water on its surface. Atri’s team now proposes a broader concept: the Radiolytic Habitable Zone. This includes areas where cosmic rays could interact with underground water, potentially providing a source of energy for microbial life via radiolysis.
Applying the Radiolytic Habitable Zone concept may prompt future space missions to rethink their approach. Rather than focusing solely on surface conditions, scientists may begin to prioritize tools capable of detecting chemical energy generated by radiation below the surface. This could yield a new set of promising targets in the ongoing search for life—even right here in our solar neighborhood.
The paper, “Estimating the Potential of Ionizing Radiation-induced Radiolysis for Microbial Metabolism on Terrestrial Planets and Satellites with Rarefied Atmospheres,” appeared on July 28, 2025, in the International Journal of Astrobiology.
Ryan Whalen covers science and technology for The Debrief. He holds an MA in History and a Master of Library and Information Science with a certificate in Data Science. He can be contacted at ryan@thedebrief.org, and follow him on Twitter @mdntwvlf.