> We sought evidence that the little lake existed before the event. Reliable, pre-1908 maps of this uninhabited region of Siberia are not easy to come by, but we found a czarist military map from 1883 that fails to show the lake. Testimony by local Evenk natives also asserts that a lake was produced by the 1908 explosion.<p>this is about as suggestive a set of facts as you're ever likely to get. We don't need any exotic theories about Tesla or aliens.<p>> The first step in preparing ourselves would be to decide whether the cosmic object that affected Siberia was an asteroid or a comet.<p>What would we do differently if we determined conclusively which it was? A comet <i>could</i> strike Earth, even if Tunguska was not one. Knowing that it happened doesn't make it any more likely it could happen again.