Nonextensivity and Galaxy Clustering in the Universe
  We investigate two important questions about the use of the nonextensive thermostatistics (NETS) formalism in the context of nonlinear galaxy clustering in the Universe. Firstly, we define a quantitative criterion for justifying nonextensivity at different physical scales. Then, we discuss the physics behind the ansatz of the entropic parameter $q(r)$. Our results suggest the approximate range where nonextensivity can be justified and, hence, give some support to the applicability of NETS to the study of large scale structures. 
Carlos Alexandre Wuensche, Andre Luiz B. Ribeiro, Fernando M. Ramos,   Reinaldo R. Rosa