SPEAKER: Ippocratis Saltas (CAAUL, Lisbon)
ABSTRACT: In this talk, I will first briefly discuss the challenges one faces when trying to explain the observed late-time acceleration of our Universe, due to the obstacles which the yet unkown physics of dark energy and dark matter place when we try to understand the true theory of gravity at large scales. In this context, I will further explain how model-independent observables have the potential to reveal whether gravity is truly modified at large scales, and will describe a fundamental, underlying relation between large-scale modifications of gravity and the (non-trivial) propagation of gravitational waves, as well as its observational implications for cosmology and astrophysics.