How long are you planning to stay here? http://xtubex.in.net/ xtube com “The spectrum steepens at the ‘knee,’ which is generally interpreted as the beginning of the end of the galactic population. Below the knee, cosmic rays are galactic in origin, while above that energy, particles from more distant regions in our universe become more and more likely,” Ruzybayev said. “These measurements provide new constraints that must be satisfied by any models that try to explain the acceleration and propagation of cosmic rays.”