Tunguska 100 years later:A space crime scene Astronomy CSI?

Astronomy CSI -A space crime scene ? On this anniversary was the object that hit Siberia on June 30, 1908, an alien spaceship, a black hole, a comet, a porous type asteroid? Tunguska explosion was 1,000 times more powerful than the atom bomb dropped on Hiroshima but many scientists still are undecided on what caused it. The latest information hinted that it was a body 10 times that of the Titanic but now say it might have been smaller. Simulations seem to suggest a lesser explosion created the devastation as well. Now there are other theories but no defintive answers. http://www.foxnews.com/story/0,2933,373608,00.html