# Study Finds Venus's Slow Spin Doomed Any Moon It Ever Had

*2026-09-13 02:01 UTC · Science · 2 min read*

> New simulations show any moon Venus once had would have spiraled inward and been torn apart by tidal forces within about 1.7 billion years.

A new study led by planetary astrophysicist Stephen Kane of the University of California, Riverside, explains why Venus, nearly Earth's twin in size and mass, has no moon. Published in The Astrophysical Journal, the research ran computer simulations spanning 4.5 billion years, testing how Venus's rotation speed, a hypothetical moon's mass, its orbital distance, and tidal friction would interact over time.

The team found that any moon Venus once had would most likely have spiraled inward and been torn apart by the planet's own gravity once it crossed Venus's Roche limit, about 2.85 Venus radii, or roughly 17,000 kilometers from the planet's center. The simulations put the likely destruction window between 30 million and 1.7 billion years after formation. A moon could only have survived under narrow conditions: a fast-spinning early Venus paired with a satellite no heavier than Earth's own Moon.

The researchers say the finding points to ordinary tidal physics rather than a single catastrophic collision. Because large moons help stabilize a planet's axial tilt and climate, Venus's slow rotation and moonless history may have left it prone to chaotic climate swings, a possible "critical branch point" that helped push Venus and Earth onto such different evolutionary paths despite their similar starting conditions.

## Sources

- [universetoday.com](https://www.universetoday.com/articles/venus-moon-would-have-been-doomed-from-the-start-says-new-paper)
- [phys.org](https://phys.org/news/2026-09-doesnt-venus-moon.html)

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TechTools News · https://techtools.cz/tools/news/article/2362-study-finds-venus-s-slow-spin-doomed-any-moon-it-ever-had
Česká verze: https://techtools.cz/tools/news/clanek/2435-studie-pomala-rotace-venuse-odsoudila-jakykoli-jeji-mesic-k-zaniku