RADIATION OF EXTREME BLACK-HOLES

The radiation from extreme Reissner-Nordstrom black holes is computed by considering the collapse of a spherical charged shell. No neutral r adiation is found, and, therefore, the black hole temperature is zero, but there is emission of charged particles if the charge to mass rati o is greater than one. The absence of thermal effects is in accord wit h the predictions of Euclidean theory and it is argued why the radiati on entropy should not be regarded as a black hole attribute. Rather, i f any entropy is to be present in the future, this is interpreted as a loss of quantum coherence in the past by the presence of the timelike wormhole made by charges. The stability of the extreme black hole to emitting uncharged particles is consistent with the conjecture of cosm ic censorship, which may thus be regarded as strengthened by the quant um theory.