The hypothesis of an impinging comet used to construct the theory of the Great Tunguska Meteor Fall of 1908 is shown to be imcompatible with the apparent existence of the intense termainal explosion of the meteor. A critical examination of and proposal for the mechanism of meteor explosions are made to shed light on the ''thermal'' explosion paradox of the Tunguska Meteoroid. A proous meteoroid model is proposed which could dispel the above-mentioned paradox.