Overview
- The UCR-led paper released this week presents computer models showing that a moon around Venus would usually spiral inward rather than move away, a result the authors reported on Monday in a preprint and journal coverage.
- Model outcomes depend on initial conditions and tidal physics, and the team found typical survival times from about 30 million to roughly 1.7 billion years depending on moon mass and Venus’s post-impact spin rate.
- The mechanism is tidal: Venus’s very slow spin places a moving synchronous radius that can overtake a moon and reverse orbital energy transfer so that the satellite loses angular momentum and falls inward.
- Key uncertainties include how Venus’s interior dissipates tidal energy and the planet’s early spin after giant impacts, so the result is model-based and not direct proof that a moon once existed.
- Finding physical evidence will be hard because Venus’s surface was largely resurfaced, so scientists say upcoming missions such as DAVINCI+ and VERITAS could supply the interior or geologic data needed to test the scenario and its implications for habitability and exoplanets.