Hey Joe, I saw some new information on Tunguska today, in this week's issue of Science:
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More Theories on Tunguska
On 30 June 1908, in the remote Tunguska forest of Siberia, a vast explosion charred and flattened trees across an area nearly as large as Rhode Island. Scientists have long been mystified as to the cause, although prevailing wisdom has it that it was an extraterrestrial chunk of ice or rock (Science, 20 August 1999, p. 1205).
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Tunguska epicenter today.
CREDIT: VITALII ROMEIKO
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But two scientists last week rejected the "E.T. hypothesis" at a conference on environmental catastrophes in London. Andrei Ol'khovatov, formerly of the Soviet Radio Instrument Industry Research Institute, noted that no one has ever found definitive traces of extraterrestrial material. There's no impact crater, and some trees near the epicenter were left untouched.
Wolfgang Kundt, an astrophysicist at Bonn University, Germany, proposed an alternative scenario: a massive gas explosion. A large natural gas deposit lies below the site, a well-known fact unconnected to the event until now, he said. Kundt has modeled a Tunguska "outgassing" and says it would fit with eyewitness accounts.
"The geophysical hypothesis could be the answer," says Jesús Martínez-Frías of the Institute of Astrobiology in Madrid, Spain. But Ol'khovatov believes the explosion was caused by a "strong coupling between subterranean and meteorological phenomena" that science is not yet ready to understand.
sciencemag.org |
