Possibility of Matter-Antimatter Separation at High Temperature

It is suggested, on the basis of a simplified model of nucleon-antinucleon interaction, that a spatial separation of baryons and antibaryons might occur in the blackbody radiation at very high temperatures, typically larger than $kT=350$ MeV. Some applications to astrophysical data, like the matter density of the universe and a mechanism for quasistellar objects, are sketched.