Events at Physics
Basic questions remain unanswered: What generates such extremely energetic particles that reach above 10^20 eV (100 EeV)? Where do they come from? How do they reach these energies? What are they? How do they interact on their way to Earth and with the Earth’s atmosphere?
A hotspot seen by TA may be the first hint of a source. Neutrino and gamma-ray follow ups may clarify this tantalizing possibility. In addition, a large increase in statistics of UHECRs is needed. Space missions are now being studied to increase the exposure to UHECR such as the JEM-EUSO mission: the Extreme Universe Space Observatory (EUSO) at the Japanese Experiment Module (JEM).