Overview

• The calculation applies to the collisionally active population, excluding long-lived bodies such as Ceres, Vesta, and Pallas.
• Roughly 20% of lost material escapes as asteroids and meteoroids that can cross Earth’s orbit, while about 80% is ground into meteoritic dust that feeds the zodiacal cloud.
• Extrapolations suggest the belt held around 50% more mass 3.5 billion years ago and has shed roughly a third since then.
• Prior estimates place the belt’s current total mass at about 3% of the Moon’s mass, underscoring how little material remains.
• The findings come from a modeling study posted as a preprint on arXiv and await peer review and independent validation.