Tunguska Blast Crater Found

Rokcet Scientist · Post by **Rokcet Scientist** » Thu Nov 08, 2007 11:43 am

Thursday November 08

A team of scientists from the Marine Science Institute in Bologna claims to have found the crater left by the aerial blast of a comet or asteroid in 1908 in the Tunguska region of Siberia. The blast flattened 770 square miles (2,000 square kilometers) of forest, but to date no remains or crater have been found. This has left open the question of what kind of object made the impact. The team believes that, contrary to previous studies, nearby Lake Cheko is only one century old and 'If the body was an asteroid, a surviving fragment may be buried beneath the lake. If it was a comet, its chemical signature should be found in the deepest layers of sediments.' The team's findings are based on a 1999 expedition to Tunguska and appeared in the August issue of the journal Terra Nova.

Go to the article: http://news.nationalgeographic.com/news ... rater.html

kbs2244 · Post by **kbs2244** » Thu Nov 08, 2007 7:17 pm

If I read that correctly, they are looking at two possibilities.
Either one of which will start a lot of disscussion.

War Arrow · Post by **War Arrow** » Fri Nov 09, 2007 7:37 am

Thought it was supposed to have come in at an angle, rather than directly from above, so surely a trench makes more sense than a circular crater anyway?

Well, any road, if this is where the thing came down, hopefully it'll put a stop to claims that it "landed".

Digit · Post by **Digit** » Fri Nov 09, 2007 12:51 pm

so surely a trench makes more sense than a circular crater anyway?

Only if the body enters at a very low angle WA, and it would have to be a very low angle indeed. Apart from other considerations the lower the angle the greater the depth of atmosphere the body will encounter, this increases the chances of the body burning up or breaking into smaller entities.

War Arrow · Post by **War Arrow** » Fri Nov 09, 2007 1:14 pm

Digit wrote:
so surely a trench makes more sense than a circular crater anyway?
Only if the body enters at a very low angle WA, and it would have to be a very low angle indeed. Apart from other considerations the lower the angle the greater the depth of atmosphere the body will encounter, this increases the chances of the body burning up or breaking into smaller entities.

Hence the mystery, I guess.

Rokcet Scientist · Post by **Rokcet Scientist** » Fri Nov 09, 2007 3:34 pm

Digit wrote:
so surely a trench makes more sense than a circular crater anyway?
Only if the body enters at a very low angle WA, and it would have to be a very low angle indeed. Apart from other considerations the lower the angle the greater the depth of atmosphere the body will encounter, this increases the chances of the body burning up or breaking into smaller entities.

Afaik it exploded. Airblast. It never hit the ground. Not in one piece anyway.

The lower the angle it entered the atmosphere with, the longer its possible track through that atmosphere. At 100,000 mph! Or some similar ridiculously high speed. The longer its track through that atmosphere, the more heat is generated. By friction with the air. At one point – today known as Tunguska – the heat got so great that the thingamejig exploded. Into smithereens. And much of that vapourized, I'm inclined to think.
Which wouldn't leave very much 'evidence', I'm afraid.

Digit · Post by **Digit** » Fri Nov 09, 2007 3:52 pm

It would leave evidence of its passage RS, trouble is, fragments, tektites etc could be very widely scattered indeed, making any finds a matter of pure chance IMO.

War Arrow · Post by **War Arrow** » Sat Nov 10, 2007 6:25 am

From reading the above, all of which makes perfect sense to me, I have to say that I'm beginning to wonder what the mystery was. It all sounds very easily explained. Of course there's "comet or meteor", but from the article, comet sounds most likely.

Digit · Post by **Digit** » Sat Nov 10, 2007 11:51 am

If it was a Comet WA it must have been one that had made numerous perihelion passages as there was no report preceeding the impact of a Comet visible in the night skys.

gunny · Post by **gunny** » Sun Nov 11, 2007 5:23 pm

Could not particles be found in the ground and tree trunks to identify the object?

Frank Harrist · Post by **Frank Harrist** » Sun Nov 11, 2007 9:49 pm

Seems to me there would be a fine layer of sediment, maybe in that lake or others nearby. Core samples should show it, but it might be very thin and hard to recognise.

Digit · Post by **Digit** » Mon Nov 12, 2007 1:48 pm

Could be a needle in a haystack jobby I'm afraid.

JohnB · Post by **JohnB** » Wed Dec 26, 2007 6:46 am

The team believes that, contrary to previous studies, nearby Lake Cheko is only one century old and 'If the body was an asteroid, a surviving fragment may be buried beneath the lake.

Pity the "previous studies" include the eyewitness accounts gathered by Leonid Kulik and some of them mention Lake Cheko by name. The lake existed before the event of 1908.

Of course you might postulate that the fragment happened to fall into the only nearby lake.

From reading the above, all of which makes perfect sense to me, I have to say that I'm beginning to wonder what the mystery was. It all sounds very easily explained. Of course there's "comet or meteor", but from the article, comet sounds most likely.

You have to keep in mind the date of the event. When Leonid Kulik made his first visit in 1927 and saw the devastation the first atomic bomb was nearly 20 years in the future. A 10 Megaton blast is not exceptional for us because we've seen the films, but back then there was literally nothing to compare it to. Even the first version of the "Big Bang" theory wouldn't be put forward for another 4 years. Explosions of that size were outside most theoretical physics. And why was there no hole?

Hence it was a mystery in 1927. Because there has yet to be definitive proof of cause, it still is.

BTW, a simple comet or meteor doesn't cut it. Kulik recorded elevated radiation levels in 1927 but these have since dropped to normal background levels. However the plants and insects are still showing increasing rates of mutation. There is so far no theory that can account for this as the mutation rate should drop as the radiation does. So far there is not a single theory put forward to explain the event that is not contradicted by at least one piece of physical evidence.

Digit · Post by **Digit** » Wed Dec 26, 2007 7:17 am

However the plants and insects are still showing increasing rates of mutation. There is so far no theory that can account for this as the mutation rate should drop as the radiation does.

That seems logical John, but is it correct. If a large(ish) are was exposed to radiation would mutations eventually decrease or would the initial mutations act as a trigger for further mutations.
Undoubtly the radiation itself is, as yet, unexplained.
The Russians of course claimed at one time that the explosion was an alien craft.
As daft as that may be it does of course offer on explanation for the radiation, and frankly at my level of physics I can't think of an alternative!

Mayonaze · Post by **Mayonaze** » Wed Dec 26, 2007 12:45 pm

I offer this only as an example of the other possible explanations that are floating around. I know nothing about the author.

http://www.mondovista.com/tesla.tunguska.html

In short, it says that Nikolas Tesla did it with his "death ray". How does the phrase go? Deus ex Machina?