Celestial mechanics is a branch of mathematics and astronomy that deals with the motions of celestial objects. The field applies principles of physics, gravitation, historically classical mechanics, to astronomical objects such as stars and planets to produce ephemeris data. Orbital mechanics (astrodynamics) is a subfield which focuses on the orbits of artificial satellites. Lunar theory is another subfield focusing on the orbit of the Moon.

For our latest developments/activities in this area, please see the listing at the end of this article.

Modern analytic celestial mechanics started over 300 years ago with Isaac Newton's Principia of 1687. The name "celestial mechanics" is more recent than that. Newton wrote that the field should be called "rational mechanics." The term "dynamics" came in a little later with Gottfried Leibniz, and over a century after Newton, Pierre-Simon Laplace introduced the term "celestial mechanics." Prior to Kepler there was little connection between exact, quantitative prediction of planetary positions, using geometrical or arithmetical techniques, and contemporary discussions of the physical causes of the planets' motion.

Solar system dynamics

The gravity force acting over eons has provided the solar system with an intricate dynamical structure, much of it revealed by recent space missions. Mathematical tools and physical models are needed for a complete understanding of the subject.

This is a multi-disciplinary subject that combines expertises from Geophysics, Dynamical Systems, and Numerical Simulations. We study the geophysical effects that modify the spin and the orbits of planets and satellites, in particular tidal effects and core-mantle friction.

Is the activity level of HD 80606 influenced by its eccentric planet?, P. Figueira, A. Santerne, A. Suárez Mascareño, J. Gomes da Silva, L. Abe, V. Zh. Adibekyan, P. Bendjoya, A. C. M. Correia, E. Delgado-Mena, J. P. Faria, G. Hebrard, C. Lovis, M. Oshagh, J.-P. Rivet, N. C. Santos, O. Suarez, A. A. Vidotto, Astronomy & Astrophysics (2016), 592, A43; e-Print: arXiv:1606.05549 [astro-ph].

Abstract: As a new post-doc of the Physics department, I would like to take this opportunity to introduce myself scientifically. I will discuss my work on "applied dynamics", in which I use the AMUSE framework to model dense stellar systems.

Abstract: At the end of the 19th century the existence os a planet beyond Neptune was in debate. In 1930, Pluto was discovered, but too far from the prediction. In 1992 we found out that Pluto is actually a member of a huge belt of icy bodies orbiting beyond Neptune.

Gr@v member António P. Morais gave a talk at Escola Secundária José Régio in Vila do Conde with title "Do Infinitamente Grande ao Infinitamente Pequeno - uma jornada pelas interações fundamentais na natureza". António was an invited speaker to participate in a sequence of seminars entitled "A Biblioteca convida...", and presented to 11th and 12th grade Science and Technology students the four fundamental interactions in nature and how have they shaped our Universe.

Abstract: In this talk, we will discuss a simplified method to formulate the problem of a self-gravitating viscoelastic body: the Pseudo-rigid body method. We will see comparisons of this approach with others commonly presented in some papers and what is the qualitative and quantitative information that this model can provide. We will also remark that there is no need to restrict the problem to the planar case and how it can be easily generalized to the two-body problem.

Our group coordinated the "Numerical Relativity and High Energy Physics" IRSES network (2012-2015). Here is a list of the global network meetings organized: