Abstract | From satellites orbiting about the Earth to the large-scale structure of the universe, all astrophysical systems are dominated by gravitational forces. In theory, this should make it easy for us to test General Relativity (GR) and its many proposed extensions. In practice, a synthesis of all our constraints on gravity is rarely attempted, largely because we lack a quantitative formalism for comparing gravitational systems on very different scales in the universe. For example, how does one link black hole physics to the CMB? I will propose one formalism for achieving this synthesis, and use it to construct a parameter space containing all current tests of gravity. I’ll point out some unexpected features of this diagram, focussing in particular on a) parts of the parameter space targeted by upcoming experiments, and b) uncharted `gravitational deserts’. The hope is that this parameter space can reveal new ways to test GR, and perhaps better ways to modify it.

Short Talk | Maria Salatino, (Princeton University)
"PILOT: an experiment for measuring the interstellar dust polarization"

In this talk, I will present PILOT: a stratospheric balloon-borne experiment of the French Space Agency (CNES) aimed at the measurement of the interstellar dust polarization in the diffuse interstellar medium at high angular resolution in a frequency band centered on 1250 GHz. The PILOT polarimeter exploits a half wave plate rotating at 2K, in the so-called "step and integrate" configuration, followed by a fixed polarizer. On September 20, 2015 PILOT has successfully performed its first flight, observing the sky for about 20 hours, from Timmins (Ontario).