Oct 9
3rd Annual Verbrugge Memorial Lecture
Our galaxy and others like it are pervaded by a very low density gas called the interstellar medium. Less than one in a billion of these interstellar gas particles is a cosmic ray, traveling at nearly the speed of light. This tiny fraction of particles carries about as much energy as all the rest of the gas. Their very existence is a surprise, given that we expect from thermodynamics that gas particle energies should follow a Bell curve (or more exactly, Fermi-Dirac of Maxwell-Boltzmann statistics). These particles exist only because the interstellar medium has a magnetic field which allows these particles to tap into large scale sources of energy like supernova explosions and galactic rotation. . Even more surprisingly, cosmic rays have an effect on these large scale energy sources. I'll explain how we think all this works and how cosmic rays are a window into high energy processes in the Universe.