Cosmic rays are high-energy particles (i.e., atomic nuclei) that constantly rain down on us from space. While many cosmic rays are produced by the Sun, much higher energy cosmic rays are produced throughout the Milky Way galaxy by supernova explosions. The source of the most energetic cosmic rays, however, is still unknown but must lie beyond the Milky Way. These extra-galactic cosmic rays are the highest energy particles ever measured and occupy a unique position in astrophysics. The origin and acceleration of cosmic rays is an important unsolved problem in high-energy astrophysics. The history and future of cosmic ray science will be discussed in this lecture.

Registration deadline: Dec. 4