Tunguska Impact Crater Found?

BigBadBus writes in with a claim by an Italian team that they may have found an impact crater resulting from the 1908 Tunguska explosion over Siberia. The BBC story quotes a number of impact experts who doubt the Italians' claim. "A University of Bologna team says a lake near the epicenter of the blast may be occupying a crater hollowed out by a chunk of rock that hit the ground. Lake Cheko — though shallow — fits the proportions of a small, bowl-shaped impact crater, say the Italy-based scientists. Their investigation of the lake bottom's geology reveals a funnel-like shape not seen in neighboring lakes. In addition, a geophysics survey of the lake bed has turned up an unusual feature about 10m down which could either be compacted lake sediments or a buried fragment of space rock."

Comments

any idea how large the region is?

[iHasaFlavour]

Tunguska is big, really big..

And extremely remote. It's not even slightly surprising that this was missed.

The original expidition didn't head to the impact site until years after the event, and still they found a devastated surface, and no-one went back again for a very long time.

Until fairly recently it just wasn't feasable to do any kind of large scale study of the region. I think people sometimes forget just how barking huge our planet is, you'd be amazed at the number of area's that are still effectivelly blanks on the map, or mapped by air/satellite only.

Re:Shouldn't this be easy to prove?

[btgreat]

Though he said he didn't have positive evidence, it does sound like they have negative evidence. The way you describe their conclusions makes it seem like there was no other reason for a lake to be there so it must have been a crater. What it sounds like to me is that instead of there being no other theories contradicting his case, they were able to disprove those other theories, and all that was left is impact crater.

I don't think there was absence of evidence, it was just that the evidence applied to other theories rather than the impact crater. Simple deductive reasoning: A lake was formed. It could have been by methods A, B, or C. We have evidence that it wasn't A or B. Thus it was C.

Semantics aside, some of the material presented in the article does make the researchers' conclusion seem somewhat dubious. I'm not arguing that the lake was the crater, just that it is possible that the professor is more justified than the article might make him appear at first glance.

Re:Impact, eh?

[himi]

I call bullshit simply based on the question of where the hell Tesla would have gotten the ~80 petajoules of energy needed for a 20 megaton explosion, regardless of how wonderful his deathray may have been. Even if he was charging some massive bank of capacitors for a year, that would require 2.5GW for the whole year, which is utterly ridiculous for 1908.

himi