Fundamental physics and cosmology with the Einstein Telescope

<!--HTML--><p>The Einstein Telescope is a proposed &nbsp;third-generation gravitational wave detector, to be build in Europe in the next decade. Its sensitivity will allow us to explore the depths on the Universe with gravitational waves. It is expected to detect of order 10^5 &nbsp;binary black holes and binary neutron stars per year, with &nbsp;binary black holes &nbsp;potentially detectable up to redshift z=O(100) and binary neutron stars up to z\simeq 3. Many of these signals will be reconstructed with remarkable accuracy, up to cosmological distances. We will discuss the impact that these observations might have on fundamental physics, cosmology and astrophysics.</p>