Rogue Moons: Warmth Without a Star ⚡ экспресс
Moons of free-floating planets can sustain surface liquid water thanks to tidal heating, amplified during the planet's ejection from the system. Earlier models predicted habitability under thick CO₂ atmospheres, but faced condensation and collapse issues at high pressures. This work developed a self-consistent model coupling radiative transfer and equilibrium chemistry with condensation to simulate hydrogen-dominated atmospheres with initial C, O, N inventories. It was found that collision-induced absorption of H₂ effectively traps heat, maintaining temperatures fit for liquid water for up to 4.3 billion years (pressure-dependent) without condensation collapse. Wet-dry cycles, driven by strong tides, combined with alkalinity from dissolved NH₃, create favorable conditions for RNA polymerization and, hence, the origin of life.
Rogue planets, ejected from star systems, may harbor life on their moons. A moon of such a planet can preserve heat and liquid water for billions of years. The whole secret lies in a reliable "blanket" and an internal "stove."
But without a blanket, heat escapes. Carbon dioxide is a poor insulator: it freezes out too easily. A dense hydrogen envelope acts like a down comforter, trapping heat. This allows liquid water to exist for up to 4.3 billion years.
Add a bit of carbon, nitrogen, and ammonia to the atmosphere, and you get an alkaline environment, perfect for the chemistry of life. Even in the pitch darkness of interstellar space, warm worlds can bloom.
🎯 The hydrogen "fur coat" of such a moon can weigh as much as several Earth oceans, yet remain transparent—on the surface, eternal twilight, but warm.