Did Venus Eat Its Own Moon? Scientists Uncover a Shocking Possibility

A moon drawn toward Venus

The simulations indicate that Venus may not have needed a major catastrophe to lose a moon. Kane, an astrophysicist at the University of California, Riverside, said the planet’s gravity and rotation could have caused a moon to fall onto its surface.

Kane tested the model first by reproducing the known evolution of Earth and its moon. He then varied Venus’ rotation rate and tested hypothetical moons ranging from half to ten times the mass of Earth’s moon.

What the simulations found

In most of the model runs, a moon collided with Venus. The more massive the moon, the sooner it struck the planet. The results suggest Venus could not have retained a moon indefinitely, even if one had formed. Kane said slow rotation could also lead moons to crash into planets orbiting other stars, potentially changing their histories.

Moons and planetary habitability

The connection between a planet’s spin and a moon’s orbit can be measured in the Earth-moon system. Apollo 11 mirrors on the lunar surface let scientists track the moon’s distance from Earth; Kane said it is receding by about four centimeters, or 1.6 inches, each year.