Séminaire Exoplanètes / |
| « There is still some order out of this chaos! » |
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Federico Mogavero |
| The motion of the inner planets within the Solar System exhibits chaotic behavior, which precludes deterministic predictions of their future positions beyond a few tens of millions of years. Nonetheless, numerical simulations reveal a remarkable stability in their orbits over timescales comparable to the age of the Solar System. The likelihood of Mercury's eccentricity exceeding 0.7, potentially resulting in catastrophic events such as close encounters or collisions with either Venus or the Sun, is estimated to be only about 1% over the next 5 billion years. In this talk, I will discuss recent advancements that highlight the hierarchical structure of chaos in the inner Solar System. I will show how certain symmetries characterize the strongest resonant interactions responsible for orbital chaos. These symmetries are weakly broken by secondary resonances, leading to the existence of quasi-conserved quantities that relate to the longest timescales of the dynamics, as notably evidenced by a principal component analysis of orbital solutions. By providing long-term memory of the current orbital configuration, these quasi-integrals of motion effectively constrain the chaotic diffusion of the inner orbits, playing a crucial role in their statistical stability over the lifetime of the Solar System. |
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mardi 30 avril 2024 - 14:00 Salle des séminaires Évry Schatzman Institut d'Astrophysique de Paris |
| Page web du séminaire / Seminar's webpage |