... Science Frontiers ONLINE No. 139: Jan-Feb 2002 Issue Contents Other pages Home Page Science Frontiers Online All Issues This Issue Sourcebook Project Sourcebook Subjects Tunguska: An Inside Job?Virtually all speculation about the 1908 Tunguska Event assumes an external cause: a meteor, a comet, an asteroid, or even the accidental explosion of an alien spaceship. A recent meeting of Tunguska experts in Russia looked down rather than up for Tunguska's initiating phenomenon. In this open-minded review, two little-publicized but highly pertinent Tunguska observations were discussed. The catastrophe had five centers of destruction rather than one. At the Tunguska site are many large root stumps, not yet rotted away, that cannot be linked to any pits associated with their origin. These stumps were apparently blown out of the ground and hurled dozens of meters from where they stood prior to the Event. Next to be considered were the unappreciated similarities between the Tunguska Event and the 1883 explosion of Krakatoa. The four bright nights in Europe and western Asia, straddling 30 June 1908, are remimiscent of the 1883 Krakatoa outburst, they ask for transient scatterers in the upper atmosphere, above 500 km, at heights which only methane and hydrogen are light enough to reach in sufficient quantity. Fast-rising natural gas has been repeatedly detected in recent years, in the form of "mystery clouds"---by airplane pilots---and indirectly as pockmarks on 6% of the sea floor. In other words, Tunguska might well have been---not an extraterrestrial impact--- ...