Experimental analysis of lateral impact on planar brittle material: spatial properties of the cracks

The breakup of glass and alumina plates due to planar impacts on one of their lateral sides is studied. Particular attention is given to investigating the spatial location of the cracks within the plates. Analysis based on a phenomenological model suggests that bifurcations along the cracks' paths are more likely to take place closer to the impact region than far away from it, i. e., the bifurcation probability seems to lower as the perpendicular distance from the impacted lateral in- creases. It is also found that many observables are not sensitive to the plate material used in this work, as long as the fragment multiplicities corresponding to the fragmentation of the plates are similar. This gives support to the universal properties of the fragmentation process reported in for- mer experiments. However, even under the just mentioned circumstances, some spatial observables are capable of distinguishing the material of which the plates are made and, therefore, it suggests that this universality should be carefully investigated

Dark Matter and Dark Energy due to Photons that Attract or Repel Each Other

The Through a simple model we study the possibility of photon with mass and charge that can produce an attractive or repulsive force at galactic distances. The main source of the dark energy can be provided by the non-vanishing photon mass during the period of dark radiation of the Universe. A simple analysis shows that the non-vanishing photon mass of the order of is consistent with the current observations. For distances separating nearby galaxies dominates the force of Newtonian attraction between photonic masses (Dark Matter). For distant galaxies dominates the repulsive electrical force between photon charges (Dark Energy)