Extragalactic cosmic ray Extragalactic cosmic ray Extragalactic cosmic rays are very-high-energy particles that flow into the Solar System from beyond the Milky Way galaxy. The energies these particles possess are in excess of 10 eV. Unlike solar or galactic cosmic rays, little is known about the origins of extragalactic cosmic rays. This is largely due to a lack of statistics: only about 1 extragalactic cosmic ray particle per square meter per year reaches the Earth's surface (see figure). There are many ideas about which processes may be responsible for cosmic rays with such high energies. In the 'bottom-up' approach, cosmic rays gain more
First Cambridge Catalogue of Radio Sources axis is not exactly East-West. The survey found radio sources in close proximity to four of the five major extragalactic nebulae, namely M31, M33, M101 and M51, corresponding to sources 00.01, 01.01, 14.01 and 13.01 respectively. Only M81 had no observed radio source. The isotropy of the sources lead the team to conclude that radio stars were either local phenomena, or extragalactic. First Cambridge Catalogue of Radio Sources The First Cambridge Catalogue of Radio Sources (1C) refers to the catalogue listed in the article "Ryle M, Smith F G & Elsmore B (1950) MNRAS vol 110 pp508-523 "A Preliminary Survey