GENERALIZATION OF THE PLANCK RADIATION LAW AND APPLICATION TO THE COSMIC MICROWAVE BACKGROUND-RADIATION

Within the framework of the recently introduced nonextensive statistic al mechanics, we generalize the Planck law for the blackbody radiation . The generalized thermal spectrum contains an additional parameter q, for which q = 1 in the Planck limit. For the cosmic microwave backgro und radiation, we find a 95% confidence limit of \q - 1\ < 3.6 x 10(-5 ) from the data of Mather et al. [Astrophys. J. 420, 439 (1994)] that were obtained with the Cosmic Background Explorer satellite, under the assumption that the internal reference of the apparatus has a Planck spectrum.