SEMINÁRIO DOS CEM ANOS DE POINCARÈ

Via Alexandre Correia, a quem agradeço, deixo um vídeo de uma conferência realizada em Aveiro comemorativa dos cem anos da morte de Henri Poincaré, o "pai do caos", por parte de um dos maiores especialistas em caos.

Stability and Chaos in the Solar System: From Poincaré to the present.

Jacques Laskar, CNRS, Observatoire de Paris

10 dezembro 2012, 14h30,
Anfiteatro do Dep. Física,Universidade de Aveiro.

Abstract:

Some of the most famous works of Henri Poincaré (1854-1912) have been 

motivated by the problem of the stability of the Solar System.

Indeed, since its formulation by Newton, this problem has fascinated
astronomers and mathematicians, searching to prove the stability of
the Solar System. Poincaré demonstrated that the perturbative methods
of the astronomers could not be used to provide an answer to the
problem of stability on infinite time because the series that were
used are in general  divergent. At the same time he believed that the
dissipative terms would be of larger importance than the conservative
neglected terms, leading to a stable final state for the Solar System.
In the following of the work of Poincaré, KAM theorems have provided
new hopes for mathematicians to prove the stability of  the Solar
System. On the opposite, the  recent numerical works on realistic
models of the Solar System show that the system is unstable in the
strong sense and that planetary collisions are possible within the
lifetime of the Sun.