Cosmic rays from galactic and extragalactic sources

A model is presented in which the bulk of the cosmic rays comprises two components: one, from galactic sources (probably pulsars) and the other having a universal, i.e. extragalactic, origin. Attention is directed particularly towards the particles above about 10 17 eV which, like those below 10 14 eV, are proposed to be of universal origin, it is shown that if these particles have a production spectrum having constant exponent (differential value=-2.75) then interaction with the black-body radiation gives a spectrum at the earth not inconsistent with observation. In this model the extragalactic sources of cosmic rays do not increase in total number or in intensity at high red shifts.