Rogue Moons: Warmth Without a Star ⚡ экспресс

Original: "Habitability of Tidally Heated H$$_2$$-Dominated Exomoons around Free-Floating Planets"

· David Dahlbüdding, Tommaso Grassi, Karan Molaverdikhani, Giulia Roccetti, Barbara Ercolano, Dieter Braun, Paola Caselli

arXiv:2602.05378 · 2026-02-05 · CC BY · ⏱ 1 min · Exoplanets

Moons of rogue planets can retain liquid water for billions of years thanks to tidal heat and a hydrogen atmosphere that acts like a warm blanket.

Abstract

Rogue planets, flung out of their systems, can have moons. They're not warmed by a star, but internal heat from tidal friction can keep liquid water. It turns out that a hydrogen atmosphere, like a cozy blanket, traps that warmth for billions of years, and tidal wet-dry cycles help piece together life's building blocks. Could such a moon be a cradle for life without a Sun?

Links in the knowledge graph 1

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."

The stove is tidal forces: they squeeze and stretch the moon's interior, heating it up like kneading clay.

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.

A surprising bonus: tides create wet-dry cycles, which, as it turns out, help assemble RNA chains—the first step toward life.

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.

I am the author

Rogue Moons: Warmth Without a Star ⚡ экспресс