Cosmic Ray Diffusion from the Galactic Spiral Arms, Iron Meteorites, and   a possible climatic connection?
  We construct a Galactic cosmic ray (CR) diffusion model while considering that CR sources reside predominantly in the Galactic spiral arms. We find that the CR flux (CRF) reaching the solar system should periodically increase each crossing of a Galactic spiral arm. We search for this signal in the CR exposure age record of Iron meteorites and confirm this prediction. We then check the hypothesis that climate, and in particular the temperature, is affected by the CRF to the extent that glaciations can be induced or completely hindered by possible climatic variations. We find that although the geological evidence for the occurrence of IAEs in the past Eon is not unequivocal, it appears to have a nontrivial correlation with the spiral arm crossings--agreeing in period and phase. Thus, a better timing study of glaciations could either confirm this result as an explanation to the occurrence of IAEs or refute a CRF climatic connection. 
Nir J. Shaviv (CITA, U. of Toronto & Racah Inst. of Physics, Hebrew   University)