Study Finds Rogue-Planet Moons Could Keep Oceans for 4.3 Billion Years Under 100-Bar Hydrogen
Updated
Updated · spacedaily.com · Jul 20
Study Finds Rogue-Planet Moons Could Keep Oceans for 4.3 Billion Years Under 100-Bar Hydrogen
1 articles · Updated · spacedaily.com · Jul 20
Summary
4.341 billion years is the longest span a modeled Earth-sized moon could keep surface liquid water while orbiting a Jupiter-like rogue planet, according to a 2026 study.
100 bars of hydrogen and sustained tidal heating were the crucial conditions: the same model gave about 95 million years at 1 bar and 699 million years at 10 bars.
6,945 moons remained bound after simulated planet ejections, and 43% of those with 100-bar atmospheres reached liquid-water temperatures at some point as eccentric orbits gradually lost heat.
Hydrogen outperformed earlier carbon-dioxide scenarios because collision-induced absorption trapped heat without the atmospheric collapse risk from CO2 freezing in extreme cold.
No such exomoon has been confirmed, and the one-dimensional model omitted oceans, geology, clouds and biology, so the work expands theoretical habitability rather than showing starless oceans are common or inhabited.