Scientists have used computer simulations to explore how cosmic collisions might affect the ability of icy moons to sustain life. Many moons orbiting the planets Saturn, Uranus, and Neptune are thought to have vast oceans of liquid water hidden beneath thick layers of ice. These moons are considered promising places to search for life beyond Earth, but the outer solar system is a busy place, with frequent impacts from asteroids and other space objects. This raises an important question: could these collisions destroy the oceans and the potential for life on these moons? A study led by researchers from the University of Maryland and published in the journal Nature Astronomy found that major collisions do not significantly change whether an icy moon can maintain a liquid ocean. The research used simulations to show that even the largest impacts are unlikely to either eliminate an existing ocean or create one from a previously frozen state. Lead author Marc Neveu explained that if a moon had an ocean before a collision, it is likely to keep it afterward, and if it didn’t have one, it probably won’t gain one either. The study combined two types of simulations: one that modeled the immediate effects of a collision, such as the breaking apart and reassembly of ice and rock, and another that simulated how the moon’s interior would evolve thermally over billions of years. Researchers looked at moons with radii of about 500 and 1,000 kilometers, simulating the effects of impacts from smaller space objects. The findings showed that larger moons can retain or even thicken their oceans over time due to the heat generated by impacts, while smaller moons may lose some of their insulating layers, making it harder to maintain an ocean. However, the possibility of an ocean still exists on smaller moons, though it might be more fragile. The study has implications for moons such as Rhea, one of Saturn’s satellites, which shows signs of a possible past collision. Understanding the effects of impacts on icy moons could guide future space missions, helping scientists decide where to focus their search for life and what tools to use. However, the researchers note that a moon’s collision history is just one factor in its potential to host life. Other processes, such as tidal heating from gravitational forces, also play important roles in maintaining conditions suitable for life.