Physics Cosmic Scale

Asteroids don't stay in neat orbits; they drift around like ink in a glass of water until they eventually get kicked out of the solar system.

March 23, 2026

Original Paper

Stochastic behavior along mean motion resonances in the restricted planar 3-body problem

Marcel Guardia, Vadim Kaloshin, Pau Martín, Pablo Roldan

arXiv · 2603.19894

The Takeaway

Astronomers have long known about gaps in the asteroid belt, but this study shows that gravity at those specific spots behaves more like a fluid than a clockwork mechanism. This 'stochastic diffusion' causes asteroids to wander randomly until they are ejected, explaining why these regions remain empty.

From the abstract

One of the most remarkable instability zones in the Solar system are Kirkwood gaps in the asteroid belt. In this paper we analyze instabilities in the famous Kirkwood gap $3:1$ in the regime of small eccentricity of Jupiter. Mathematically speaking, we study the evolution of asteroids under the influence of the Sun and Jupiter using the restricted planar elliptic 3-body problem (RPE3BP) for initial conditions near a mean motion resonance 3:1. The main result exhibits stochastic diffusing behavio