Venus may have consumed its own moon, study suggests

A new study led by astrophysicist Stephen Kane from the University of California, Riverside, suggests that Venus may have once possessed a moon that was eventually consumed by the planet. While Venus shares a similar size, mass, and structure with Earth, it lacks a natural satellite, a long-standing astronomical mystery.

Researchers propose that the planet's slow rotation and gravitational tidal forces caused a hypothetical moon to follow a descending spiral rather than moving away. Unlike Earth, where the Moon moves away at approximately four centimeters per year due to Earth's relatively fast rotation, Venus takes about 243 Earth days to complete a single rotation. This slow rotation could cause a moon to lose orbital altitude and eventually collide with the planet's surface.

Using computer models based on gravitational physics, the team tested various rotation speeds and lunar masses. The study does not definitively prove that Venus had a moon, but it demonstrates that if one had formed, the planet's physical characteristics would have made it unlikely to survive throughout the planet's history.