Venus Likely Swallowed Its Moon, New Study Suggests

A new study from the University of California, Riverside, proposes that Venus once had a moon that spiraled inward and was consumed by the planet because of Venus’s extremely slow rotation. Computer models simulating the gravitational dynamics of hypothetical Venusian satellites of various sizes show that all would have collapsed into the planet within the first billion years of its history. The research contrasts Venus’s 243‑day spin with Earth’s 24‑hour rotation, which pushes the Moon away at 4 cm per year. The finding offers a new explanation for why Venus, the Earth‑sized planet, has no lunar companion, and it refines our understanding of early inner‑solar‑system collisions. NASA’s upcoming DAVINCI+ and VERITAS missions may further test the planet’s past by probing its atmosphere and geology.