A condensed matter analogy of impact crater formation
  Impact craters exist on various solid objects in the planetary system. A simplified analogy of the process of their formation is here analyzed by standard solid state physics and the so called dynamic quantized fracture mechanics. An expression which links the crater volume to the parameters of the impactor and the target is obtained within the two approaches. For low impactor energy, this expression is of the same mathematical form as the one resulting from recent experiments.It is shown that the formation of an impact crater is possible even without heating of the target, if the critical stress in the target satisfies certain conditions. The critical value of the stress needed for the occurence of a fracture is calculated for three craters: two terrestrial and one lunar crater. The approach presented here uses only measurable material parameters, and is therefore more realistic than the treatement of the same problem using the cohesive energy of materials. 
V.Celebonovic (Inst. of Physics, University of Belgrade, Serbia)
astro-ph.EP cond-mat.mtrl-sci