Venus Likely Lost Its Moon to Its Own Slow Spin

New computer models suggest that Venus once orbited a natural satellite, but the planet’s sluggish rotation would have pulled the moon inward rather than pushing it away. Unlike Earth’s moon, which recedes slowly, a moon around Venus would experience strong tidal forces that cause its orbit to decay. The simulations show that even modestly sized moons would spiral toward the planet, with larger bodies falling in even more quickly. The result would be a collision that would erase any lunar remnant. The study explains why Venus has no moon today and highlights how a planet’s spin rate shapes its satellite system. It also provides a new framework for interpreting the histories of other slow‑rotating worlds.