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Public Talk — Ke Fang
February 20, 2020 @ 6:00 pm - 7:00 pm
Speaker: Ke Fang
Title: The Most Energetic Particles in the Universe
Cosmic rays are protons and atomic nuclei that move at nearly the speed of light. The energy of a tiny fraction of cosmic rays, named ultrahigh energy cosmic rays, can be a million times higher than that reachable by man-made accelerators, making them the most energetic and rarest of particles in the Universe. First detected in the 1960s, ultrahigh-energy cosmic rays have attracted decades of effort in understanding their origins. The problem remains unsolved today and is listed among the biggest questions in science by Nature. This talk will explain how scientists measure these mysterious particles and what has been learned so far. You will also hear about a few physical processes in astrophysical objects that could accelerate particles to extreme energies. The future of the study is bright. The next-generation high energy neutrino experiments will detect the smoking gun signal of the sources by finding the interaction products of the ultrahigh-energy cosmic rays.