mardi 13 mars 2018, par Marek Abramowicz (Varsovie et Göteborg)
Mardi 20 mars 2018 à 14h00 , Lieu : Salle 204 du bâtiment Evry Schatzman (18)
An observational proof for the existence of the event horizon is fundamentally impossible. However, there are many strong "near proofs". One of them, recently pointed out by Thibault Damour, and further discussed by Vitor Cardoso and others, is an absence of echoes in the gravitational wave ringdowns. I will give a pedagogical explanation of the issue in terms of the optical geometry. The optical geometry was introduced (in a different context) by Garry Gibbons and later explained dynamically by Brandon Carter, Jean-Pierre Lasota and me, and explored by many other authors.
