Solar-System Bodies as Teaching Tools in Fundamental Physics

We show how asteroids can be used as teaching tools in fundamental physics. Current gravitational theory assumes that all bodies fall with the same acceleration in the same gravitational field. But this assumption, known as the Equivalence Principle, is violated to some degree in nearly all theories that attempt to unify gravitation with the other fundamental forces of nature. In such theories, bodies with different compositions can fall at different rates, producing small non-Keplerian distortions in their orbits. We focus on the unique all-metal asteroid 16 Psyche as a test case. Using Kepler’s laws of planetary motion together with recent observational data on the orbital motions of Psyche and its neighbors, students are able to derive new constraints on current theories in fundamental physics. These constraints take on particular interest since NASA has just announced plans to visit Psyche in 2026.