I am the Schwarzmann Chair Professor of Physics at The Racah Institute of Physics at The Hebrew University of Jerusalem. My research is in relativistic astrophysics at the link between astrophysics and fundamental theories - relativity and high-energy physics. This enables using astronomical observations to explore physics under extreme conditions that cannot be explored otherwise on Earth. It includes studies of Gamma-Ray Bursts, the strongest explosions in the Universe, Binary neutron star mergers that are sources of Gravitational waves and the foundries of the heaviest elements like Gold, Uranium and Plotonium, Tidal Distuprion Events in which stars are torn apart by Massive Black Holes and the origin of the Highest Energy Cosmic Rays. I am the receipient of the EMET prize for Physics and Space Sciences for 2019 and of two Advanced ERC grants (GRBs and TReX) on these topics.