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Details Emerging On Tunguska Impact Crater
#space_on_irc.freenode.net (Dusty) writes "Lake Cheko in Siberia has been noted as the probable crater of the 1908 Siberian Tunguska event. This news was discussed here in December, but details on the crater were scant. Now a new paper written by Luca Gasperini, Enrico Bonatti, and Giuseppe Longo (the same team in Bologna, Italy that made news in December) has a horde of new details on the supposed crater. The team visited Lake Cheko complete with their own catamaran and completed ground-penetrating radar maps, side-scanning sonar images, aerial images, and some sample collection of Lake Cheko. Intriguingly, they also imaged an object under the sediment that may be a fragment of the impacting body. Their paper (PDF) includes a lot more details including images, side-scanning sonar image, a 3-D view of the lake, a morphobathymetric map. It's an interesting read, these dudes are good. They plan to return this summer and drill the core if weather permits, hopefully answering the question once and for all." The same team also has a more discursive article in the current Scientific American that includes some detail on the working conditions in the Siberian summer. Think: mosquitos.
err, post I mean
"The first time I got drunk, I got married. The second time I bought a chimpanzee, after that I stayed sober" Arian Seid
...thirty-five feet long, weighing approximately six hundred pounds.
BOOOM!!!
What else do we need to know about the Tunguska event?
Ok, maybe it would make a cool short film by some of animation whiz. Preferably starring the squirrel from the Ice Age shorts.
The team visited Lake Cheko complete with their own catamaran
Is it really that hard to spell 'cameraman' correctly? C'mon editors! Get on it!
I have been following this team's progress with their investigation since it first came to light last year on the slash. They present a compelling case that there may be an impact body that created the lake.
I can't wait and see their results from core drilling the lake.
There have been several other impacts that were recorded by mankind (one in Estonia, recorded by Pliny the Younger).
The Tunguska event could be mis-interpreted as a nuclear strike if it were to happen today over a populated area. We need to increase our understanding of the frequency and effects of bolide impacts upon our planet.
Tisha Hayes
Seriously, the smart bet seems to be that event was caused by an asteroid strike. But until someone gathers some hard data, that's still only a hypothesis.
What self respecting scientist wouldn't go and examine the evidence? Because if it wasn't an asteroid strike...
Don't let THEM immanentize the Eschaton!
If you saw that documentary on him called The Prestige, you know he's capable of almost anything.
And vodka, and borst, and potatoes.
Invenio via vel creo
"The various samplings from the bottom of Lake Cheko (P'yavchenko, Kozlovskaya) revealed extensive development of silt up to 7 meters deep, indicating an ancient origin for the lake (tentatively estimated at 5000 to 10,000 years), thus completely contradicting the hypothesis of the formation of the lake as a result of the Tunguska meteorite fall (V. Koshelev, 1960)."
http://abob.libs.uga.edu/bobk/tungmet.html
This is what I'm talking about!
No more of that crap from idle on the front page, this is what you should be posting! This makes my geekiness tingle, this is what keeps me coming back. Please, for the love of God, more of the same!
According to Wikipedia, the lake is at 60.964 N and 101.86 E. Might make it easier to find in Google earth.
/ The Arrow
"How lovely you are. So lovely in my straightjacket..." - Nny
In Soviet Russia, Mosquito suck YOU!
... wait ... nevermind.
Oh
Knowledge is how to play a game, intelligence is how to win, wisdom is knowing what game to play.
The paper in the posting is a reply to a comment with the contrary interpretation (i.e. that Lake Cheko isn't an impact) [Same paper as PDF]. The critical comment should be cited too.
The original paper by Gasperini et al. (2007) is also available as PDF and HTML.
I'm not particularly convinced by the evidence they present. It's quite circumstantial. What they need to find and sample is an ejecta-related layer in the lake stratigraphy or in a lake nearby, and you'd think that if such a large impactor hit the ground there would be plenty of micrometeorite debris in the sediments of the surrounding area. Geomorphological evidence and age just isn't enough.
yeah, The X-Files should totally have done an episode where it turns out that the Tunguska event was the land fall of aliens. They could even call the episode Tunguska!
-- i am jack's amusing sig file
I amused that a link to goatse can be merely ruled offtopic now.
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The extra-terrestial impactor (i.e. asteroid/comet) hypothesis has been around for a long time. It has been questioned for several reasons. In particular, (i) there were bright/white nights before the event, and (ii) debris has been found in crash sites from meteorites 10000 times lighter, whereas there is none at Tunguska.
For more details and an alternative explanation, see the following.
W. Kundt (2001), "The 1908 Tunguska catastrophe", Current Science, 81: 399-407.
Dr. Kundt is at the University of Bonn. Briefly, his hypothesis is that there was a days-long leakage of natural gas, from Earth; the gas rose up and was eventually ignited by lightning. This seems to fit the evidence better.
In an earlier discussion on Slashdot, someone posted a comment claiming that there was a similar explosion of natural gas in Texas in 1992. (I googled, but could find no evidence.)
I do not understand the geology well, but it does not seem that the Italian researchers (cited in TFA) have found evidence against Kundt's hypothesis.
The Turing test cuts both ways
Wow, catamaran is an argument. My mother [In Russian] was on the first "Complex Independent Expedition" and on the few following ones in the 60s. (She is available for questions). Many many scientists spent years on the spot, checking all possible hypothesises from a crashed space craft to an exploded ice comet. The result: no actual material ever found and the forest damage shows that the explosion took place far above the surface. BTW, there are plenty of lakes there, as the area is pretty wet. Pick one on Google Maps to fit your favorite hypothesis.
From the SciAm article's photo caption: "In this artist's conception, Semen Semenov, who witnessed the blast at a distant trading post, starts to feel the heat."
That's... a really, really unfortunate name, dude.
(I love that they managed to work "heat" and "conception" into a sentence about a guy named Semen.)
I'm only wearing black until they come out with something darker.
Mosquitoes to the point of anaphylaxis (well, that was what the rig's medic was afraid of, which is why he evacuated me back to the base camp).
Mosquitoes that can maintain eye contact at a meter range (i.e you can see it's eyes at a meter range) through the window of the car, then launch an assault on this nice juicy mammal, only being stopped by the glass of the window.
Mosquitoes that can keep pace with you while driving at 40km/hr on a dirt road.
Mosquitoes that can bite you through a leather glove, 20 times in one evening's work. They choose the clipboard hand, because you can't swat with that and get your work done.
Don't get me wrong - Siberia is interesting, but don't forget the industrial strength insect repellent and the appropriate clothing. If you don't know what's appropriate, ask a bee keeper. And don't forget the vaccination against tick-borne encaphalitis (which includes Lyme disease, I believe), which takes several weeks to become effective.
Birds are not dinosaur descendants;birds are dinosaurs, for all useful meanings of "birds", "are" and "dinosaurs"
I Want To Believe!
A good education is a bit like a STD - it makes you unsuitable for a lot of jobs and gives you a desire to spread it.
There's a similar mystery right here in the U.S. The Carolina bays are elliptical depressions scattered throughout the southern Eastern U.S. seaboard. They're mostly filled with water so form small lakes, ponds, or wetlands. But they're all approximately the same shape and orientation (but not size). A variety of theories have been posed as to their origin, including a glancing comet strike (shallow angle impacts produce elliptical craters, not round). They're not as well-known as the Tunguska event, but they're a lot more accessible if you wanted to visit a mysterious possible impact site.
Well, there is little doubt by any reputable scientist that it was some form of extra-terrestrial impact, what has remained in contention for a long time was what exactly impacted at Tunguska.
One side insists it was an Asteroid, but the material that would normally be present at an asteroid impact just isn't there. Others argue it was a comet, but analysis of comets in the last decade or so has put some real doubt into that theory as well.
At this point they pretty much have almost everything else worked out, from the velocity whatever it was had, where it traveled, where it likely went kaboom. They just don't know what the make-up of the object was. This report goes a long way towards proving exactly what the celestial object was.
You are who you are, let no one tell you different. But, never close your mind to a new point of view.