The light phenomena of the Norwegian valley of Hessdalen are one of several unexplained light phenomena around the world. Scientists have investigated it since 1981 without a proven theory of what causes the phenomena. In this article, the superposition of cosmic radiation due to local distortion of Earths magnetic field is investigated as the source of the phenomena. Hessdalen has special characteristics in regard of its high concentration of minerals, valley formation and river containing minerals running through it and this could cause the cosmic radiation entering the valley from above to superimpose into the visible spectrum. This new theory is tested against the observed and unexplained special properties of the light phenomena, showing some promising results. Superposition of cosmic EM waves, or collisions of cosmic ray particles, should be further evaluated as the source.You can download the full article describing the theory for free by clicking on the icon below.