Who are we? Why are we here? As the Crosby, Stills, Nash & Young song suggests, we are stardust, the result of chemistry occurring throughout vast clouds of interstellar gas and dust. To better understand how that chemistry could create prebiotic molecules—the seeds of life on Earth and possibly elsewhere—researchers have investigated the role of low-energy electrons created as cosmic radiation traverses through ice particles. Their findings may also inform medical and environmental applications on our home planet.