One of the great natural mysteries of the world is the origin - and resting place - of whatever celestial object hit Siberia in 1908. The Tunguska explosion flattened trees over a 2,000 square kilometer area. While most scientists currently accept the idea of a stony asteroid exploding 5-10km above the surface, it's hard to visualize the celestial visitor being completely vaporized. Yet no one has found either a definite impact crater or a definite fragment of the intruder. A team led Luca Gasperini, of the Institute of Marine Science in Bologna, Italy, reports they may have found both.
Lake Cheko, 300 meters wide and 50m deep, shows an unusual, steep-sided configuration unlike other lakes in the area. This lake, about 8km from the epicenter of the blast, has been tentatively identified as a crater. The expedition reports detecting a large solid mass about 10 meters beneath the sediment on the lake floor. Is this our first piece of the Tunguska object? Hopefully, we will find out. Gasperini's team will return next summer with equipment to drill deep beneath the lake and bring up samples of the mystery mass.