MERCREDI 23 FEVRIER 2011
15 heures (Attention: horaire inhabituel!)
Salle Séminaire 5
Centre de Physique Théorique
Marseille-Luminy

Séminaire d'Intérêt Général:

Christian Marinoni
CPT

Title: A measure of the universe with a compass and a straightedge

Abstract: How can we extract information about the geometry of the universe
using only a compass and a straightedge? How do we probe the coherence
of General Relativity in the low-curvature large-scale regime? What
does the universe looks like to an "extraterrestrial" distant
observer? and how will it look in the distant future? Current methods
and answers will be reviewed and will serve as a frame for discussing
the solution that we have recently worked out to an old cosmological
problem posed by Alcock & Paczynski thirty years ago: is it possible
to fix the constitutive parameters of the Friedmann equations in a
purely geometric, model independent way? I will present our recipe and
show that the propose formalism provides the most competitive
constraints to date on the abundance and nature of the component that
is causing the expansion of the universe to accelerate.