Overview
- Researchers published the model-based study on Sept. 14–15 and report that most simulations of a hypothetical Venus moon end with the satellite spiraling inward and colliding with the planet.
- The inward fall is driven by tidal exchange of angular momentum: Venus’s very slow 243‑day rotation would transfer energy in a way that drains a moon’s orbital motion instead of pushing it away as Earth’s 24‑hour spin does.
- Model runs that first reproduced Earth–Moon evolution then varied Venus’s rotation and moon mass and placed a likely moon‑impact window early in Venus’s history, plausibly within the first billion years and in some cases from tens of millions to about 1.7 billion years after formation.
- The authors stress the result is a hypothesis based on simulations that does not prove a moon ever formed, and they note surface signs of a collision could have been erased by a major resurfacing about a billion years ago so missions like DAVINCI+ and VERITAS will be needed to seek supporting geophysical evidence.
- If confirmed, the finding implies slowly rotating rocky planets are unlikely to hold large satellites, which would affect obliquity (the tilt of a planet’s spin axis), long‑term climate stability, and how scientists assess habitability for Earth‑like exoplanets.