Rogue planets' moons may host billions of years of habitability

Astronomers propose that moons orbiting free-floating, starless rogue planets could stay warm enough for liquid water for billions of years thanks to tidal heating and hydrogen-dominated atmospheres that trap heat via collision-induced absorption (CIA). Using radiative-transfer (HELIOS) and chemistry (GGchem) codes, the study shows such exomoons could maintain long-term habitability even without a sun, though the models rely on simplifications (e.g., dry atmospheres, constant gravity) and future work will add clouds and water-vapor effects. This expands the search for life beyond traditional, star‑dependent habitable zones.