Cosmic Rays and Novæ

Abstract

IN dealing with this subject in a recent letter¹, I most unfortunately overlooked some recent work of W. Baade and F. Zwicky². These authors have advanced the highly interesting theory that cosmic rays have their origin in outbursts of super-novæ in extra-galactic nebulæ, and did so a year before the appearance of Nova Herculis prompted a search for a possible connexion between cosmic rays and nova phenomena in general. Super-novæ are thought to occur in each nebula about once in a thousand years, and, from certain hypotheses about what happens during an outburst, Baade and Zwicky show that they probably release energy sufficient to maintain the supply of cosmic radiation as observed at the earth.