Why is the Solar System so stable?
The long-term orbital stability of the inner planets in our Solar System is still an open problem: the orbits of Mercury, Venus, Earth, and Mars are highly stable over the lifetime of the Solar System, even though they are strongly chaotic.
In a study published on May 3rd 2023 in the Physical Review X journal, researchers from the Paris Observatory – PSL and CNRS explain this stability in terms of near‑symmetries and quasi‑conserved quantities.

Reference
Federico Mogavero, Nam H. Hoang and Jacques Laskar, “Timescales of Chaos in the Inner Solar System: Lyapunov Spectrum and Quasi-integrals of Motion”, Physical Review X, May 3 2023, DOI: https://doi.org/10.1103/PhysRevX.13.021018
Scientific contacts at Paris Observatory – PSL
- Federico Mogavero – post-doctoral researcher
federico.mogavero@observatoiredeparis.psl.eu - Nam H. Hoang – post-doctoral researcher
nam.hoang-hoai@observatoiredeparis.psl.eu - Jacques Laskar – CNRS research director
jacques.laskar@observatoiredeparis.psl.eu
Press releases
For more information
- Research news: “The Final Piece in the Solar System-Stability Puzzle?”,
by Katherine Wright, Deputy Editor of Physics Magazine, May 3, 2023, Physics 16, 72.
https://physics.aps.org/articles/v16/72 - Viewpoint: “Tackling the Puzzle of Our Solar System’s Stability”,
by Daniel Tamayo, Department of Physics, Harvey Mudd College, Claremont, California, May 3, 2023, Physics 16, 57.
https://physics.aps.org/articles/v16/57 - Special Feature: "How Our Solar System Avoids Planet Collisions",
comic strip, by Laura Canil and Michael Schirber, May 3, 2023, Physics 16, 73.
https://physics.aps.org/articles/v16/73