Séminaire Univers / |
| « Geometric algebra in celestial mechanics » |
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Barnabàs Deme |
| Predicting the evolution of Keplerian orbits under the effect of perturbations is among the oldest challanges in astronomy. It is important in a very wide range of astrophysical configurations, from the dynamics of minor bodies in the solar system to that of supermassive black holes in galactic nuclei. There have been several different methods to set the equations of motion and solve them: most notably, the planetary equations by Lagrange and the vectorial equations by Milankovitch. After reviewing these approaches, I will present a new formalism which is based on geometric algebra. This is a mathematical framework which is similar to the standard vector algebra but more general than that. I will show that it provides an interesting alternative description of the perturbed Kepler problem and connects it to some seemingly unrelated topics, like the geometry of spinors. I will also apply the technique to a simple but enlightening example, the evolution of a satellite around an oblate planet. |
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mardi 11 avril 2023 - 11:00 Salle des séminaires Évry Schatzman Institut d'Astrophysique de Paris |
| Pages web du séminaire / Seminar's webpage |