Relationship Among a Supernova, a Transition of Polarity of the Geomagnetic Field and the Pliocene-Pleistocene Boundary

After the Middle Miocene, two important climatic changes took place, consisting mainly of cooling in both hemispheres. One occurred between 7.0 and 5.4 Ma and another at the end of the Pliocene, which marked the beginning of the Pleistocene in approximately 2.58 Ma. The proposal of this presentation is to analyze diverse forcings of these climatic changes, such as the influence of the joint occurrence of reversions of the geomagnetic field and explosions of a supernova. These events occurred coincidentally with the cooling of Earth. Also, biological changes in those time intervals are analyzed, especially the evolution of the Hominins since the oldest hominin fossils. The characteristics of the Galactic Cosmic Rays, its influence on the climate and its potential mutogenetic effect were taken into account. Briefly, according to our analysis, it seems to be evident that together with other factors, the joint occurrence of the explosion of a supernova at less than 100 pc from the Earth and the weakening and/or reversion of the Geomagnetic Field was an important factor that promoted these two climatic and ecosystem changes.