Tunguska crater found?

[JonClarke]

http://www.space.com/scienceastronomy/070626_st_tunguska_crater.html<br /><br />This is an interesting story. They might even be right! <img src="/images/icons/smile.gif" /><br /><br />Jon <div class="Discussion_UserSignature"> <p><em>Whether we become a multi-planet species with unlimited horizons, or are forever confined to Earth will be decided in the twenty-first century amid the vast plains, rugged canyons and lofty mountains of Mars</em>  Arthur Clarke</p> </div>

 

[docm]

Cool <img src="/images/icons/smile.gif" /> <div class="Discussion_UserSignature"> </div>

 

[jenkoul]

The Russians actually checked out Lake Cheko back in the sixties, and pretty much ruled it out as the Tunguska "crater." The problem? There's no "lip" or rim around the lake of the sort an impact would cause (compare Great Barringer Crater in Arizona).<br /><br />As for the Jackson-Ryan hypothesis (primordial black-hole impact) can be characterized as a "wild (and wildly unsupported) explanation," check out http://www.vurdalak.com for a dissenting view.<br /><br />Or, you could get the whole thing in fictionalized form (goes down much easier). It's a free audiobook at http://www.podiobooks.com/title/singularity.<br /><br />Best,<br />Jenkoul

 

[MeteorWayne]

Thanx Jon, very interesting.<br />It would not of course be a crater derived from part of the object traveling at cosmic speeds, but it is possible that some chunks remained after the explosion in the atmosphere and continued in dark flight to cause "holes" rather than impact craters in the normal sense. It seems awfully deep for such a hole, but in a bog like environment, perhaps it is possible.<br /><br />I'll have to find out more about the ground surrounding the lake.<br /><br />Thanks for the heads up!<br /><br />June 30th, just after 7AM is the 99th Anniversery <img src="/images/icons/smile.gif" /> <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>

 

[yevaud]

Craters are complicated, and don't fall into a single cookie-cutter form. Plenty of room for this possibility. <div class="Discussion_UserSignature"> <p><em>Differential Diagnosis:  </em>"<strong><em>I am both amused and annoyed that you think I should be less stubborn than you are</em></strong>."<br /> </p> </div>

 

[dragon04]

I read that article. Fascinating. It's an otherwise inexplicable feature "in the neighborhood", at least!<br /><br />I would guess that someone (or someones) is hard at work figuring out the specifics and possible trajectories of the incomplete detonation/fragmentation of a larger inbound body.<br /><br />The mystery around the Tunguska blast is cool. The explanation might prove to be even more cool. <img src="/images/icons/smile.gif" /><br /><br />It starts me thinking about other impacts on the scale of Chicxilub. If a far larger body detonates in the atmosphere, it might indicate the larger explanation that the impact itself leaves us wanting for? <div class="Discussion_UserSignature"> <em>"2012.. Year of the Dragon!! Get on the Dragon Wagon!".</em> </div>

 

[JonClarke]

I've read the paper in Terra Nova. If anyone wants a copy, contact me by PM with your email address and I will send you a copy.<br /><br />Some random notes.<br /><br />Lake Cheko lies within a few km downrange of the central point of the blast, well within the devastation zone.<br /><br />The lake is elongated along the inferred flight path of the impactor.<br /><br />The lake is 400 m wide and 500 m long and 50 m deep. It has been modifed by a very shallow south west extension and a delta built up by the stream entering it. Apart from these the lake is conical in depth profile.<br /><br />The lake is developed in alluvial sediments. Seismic, radar and coring shows that the lake fill is very thin and probably young, little more than a veneer, except where the stream entering it has built up a delta. This is contrary to earlier studies.<br /><br />The permafrost is 25 m thick and beneath the permafrost are organic-rich and methane bearing sediments.<br /><br />Radar, seismic, and coring information show the the lake substrate is heavily disturbed. There is a point reflector at the deepest part that may represent indurated material.<br /><br />How might the lake be explained? the paper considers a number of hypotheses including volcanic, karst, thermokarst, fluvial excavation and impact. Volcanic they exclude because the lake is in alluvial sediments and there is no sign of volcanic activity in the region since the Triassic, more than 200 million years ago. Karst is ruled out because of the lack of limestones. They rule out thermokarst because the lake profile, a deep conical lake, is quite different from that of thermokars lakes in the area which are shallow and flat bottomed. the shape and depth of the lake do not seem consistent with fluvial erosion by a nearby river.<br /><br />That leaves impact. Lake Cheko lies almost at the centre of the largest impact event in recent times. It's orientation is consistent with being a crater formed by a large remnant of the presume <div class="Discussion_UserSignature"> <p><em>Whether we become a multi-planet species with unlimited horizons, or are forever confined to Earth will be decided in the twenty-first century amid the vast plains, rugged canyons and lofty mountains of Mars</em>  Arthur Clarke</p> </div>

 

[3488]

Yes that has always been the Achilles Heel, lack of meteoritic or cometary pieces.<br /><br />Looking at that site, its no wonder. Anyhting would be quickly buried.<br /><br />I think that lake in Tunguska is the impact crater.<br /><br />Has it been dredged yet?<br /><br />The lack of raised rim is no surprise. It was softened tundra, mud. It quickly <br />flowed back as it had no structural strength.<br /><br />Andrew Brown. <div class="Discussion_UserSignature"> <p><font color="#000080">"I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before".</font> <em><strong><font color="#000000">Linda Morabito </font></strong><font color="#800000">on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.</font></em></p><p><font size="1" color="#000080">http://www.launchphotography.com/</font><br /><br /><font size="1" color="#000080">http://anthmartian.googlepages.com/thisislandearth</font></p><p><font size="1" color="#000080">http://web.me.com/meridianijournal</font></p> </div>

 

[JonClarke]

Hi Andrew<br /><br />I gather not yet. 50 metres is quite deep and the area is quite remote. You would need to helicopter in a drill rig, barge, and supplies and accommodation. A very expensive exercise. You would rapidly run into the millions. <br /><br />If it were me I would as a first step process the existing cores for meteoric material - anomalous Ni, PGEs, fullerenes, etc. You might find impact glasses as well. Then look into more cores. Sampling the hard material would be tricky, as you would need a rig that could drill both soft and very hard material.<br /><br />Jon <div class="Discussion_UserSignature"> <p><em>Whether we become a multi-planet species with unlimited horizons, or are forever confined to Earth will be decided in the twenty-first century amid the vast plains, rugged canyons and lofty mountains of Mars</em>  Arthur Clarke</p> </div>

 

[3488]

Very true.<br /><br />But I think it would be well worth the time, money & effort.<br /><br />As you say, there are other investigations that can be persued first.<br /><br />I wonder if the area immediately surrounding the 'crater' has been search for <br />meteoric remains, etc?<br /><br />Andrew Brown. <div class="Discussion_UserSignature"> <p><font color="#000080">"I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before".</font> <em><strong><font color="#000000">Linda Morabito </font></strong><font color="#800000">on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.</font></em></p><p><font size="1" color="#000080">http://www.launchphotography.com/</font><br /><br /><font size="1" color="#000080">http://anthmartian.googlepages.com/thisislandearth</font></p><p><font size="1" color="#000080">http://web.me.com/meridianijournal</font></p> </div>

 

[CalliArcale]

<blockquote><font class="small">In reply to:</font><hr /><p>June 30th, just after 7AM is the 99th Anniversery<p><hr /></p></p></blockquote><br /><br />Pity I didn't plan a star party for it. It would be neat since there's also a nice conjunction occuring June 30: Venus and Saturn, two of the more photogenic backyard telescope targets. <div class="Discussion_UserSignature"> <p> </p><p><font color="#666699"><em>"People assume that time is a strict progression of cause to effect, but actually from a non-linear, non-subjective viewpoint it's more like a big ball of wibbly wobbly . . . timey wimey . . . stuff."</em>  -- The Tenth Doctor, "Blink"</font></p> </div>

 

[jenkoul]

Readers of this thread might be interested in a new blog, released within the hour that purports to show Lake Cheko could NOT have been the Tunguska crater, because the lake itself predates the Event.<br /><br />If interested, go to http://www.myspace.com/billdesmed, scroll down to Bill's Latest Blog Entry, and click on the "(View More)" next to "Digression I: The Tunguska Follies."<br /><br />Best,<br />Jenkoul <br /><br /><i>Link fixed</i>

 

[yevaud]

Yes well, "Page Not Found" isn't terribly informative.<br /><br />Sorry. <div class="Discussion_UserSignature"> <p><em>Differential Diagnosis:  </em>"<strong><em>I am both amused and annoyed that you think I should be less stubborn than you are</em></strong>."<br /> </p> </div>

 

[derekmcd]

I was going to mention how the scientific method works and how it is in an active process concering some of the new 'evidence', but I won't.<br /><br />Rather, I will state that the elite minds will be working on this and when peer reviewed journals arise, I will take seriously the conclusions these top scientist present to us common folk.<br /><br />Until then... a 'myspace' blog is meaningless. <div class="Discussion_UserSignature"> <div> </div><br /><div><span style="color:#0000ff" class="Apple-style-span">"If something's hard to do, then it's not worth doing." - Homer Simpson</span></div> </div>

 

[JonClarke]

Hmm, criticism from someone who thinks that Tunguska was a mini blackhole does not inspire confidence. <img src="/images/icons/wink.gif" /> <br /><br />That said, if he is right about the lake existing before the event then it can't be related to it. But the quote is rather ambiguous, I must say.<br /><br />Jon <div class="Discussion_UserSignature"> <p><em>Whether we become a multi-planet species with unlimited horizons, or are forever confined to Earth will be decided in the twenty-first century amid the vast plains, rugged canyons and lofty mountains of Mars</em>  Arthur Clarke</p> </div>

 

[jenkoul]

"Arguments from authority are worthless."<br /> -- Carl Sagan

 

[jenkoul]

Sorry about that -- the correct URL is:<br /><br />http://www.myspace.com/billdesmedt<br /><br />

 

[jenkoul]

Hi, Jon --<br /><br />Talk about ambiguity, given the incorrect URL I gave originally (and corrected above), I can't be sure from your reply whether you looked at the blog or just my post to this forum. The blog itself cites 3 quotes, all from Vasiliev's 1981 VINITI compilation "Testimony of Eyewitnesses to the Tunguska Impact."<br /><br />Black holes aside, I'd be interested in your considered response. <img src="/images/icons/smile.gif" /><br /><br />Best,<br />Jenkoul

 

[CalliArcale]

<blockquote><font class="small">In reply to:</font><hr /><p>"Arguments from authority are worthless." <p><hr /></p></p></blockquote><br /><br />True, but it's important to remember that arguments *by* authority are not necessarily worthless. I often seen it where one party will make an argument from authority and get called on it, but in such a way that the other party is actually arguing that arguments *by* authority are worthless -- without realizing that they are committing essentially the inverse of the usual logical fallacy. (One specific variant of this is referred to as the "Galileo Gambit".)<br /><br />In any case, you're right -- arguments deserve to be judged on their merits rather than their authorship. <div class="Discussion_UserSignature"> <p> </p><p><font color="#666699"><em>"People assume that time is a strict progression of cause to effect, but actually from a non-linear, non-subjective viewpoint it's more like a big ball of wibbly wobbly . . . timey wimey . . . stuff."</em>  -- The Tenth Doctor, "Blink"</font></p> </div>

 

[jimcolyer]

I doubt that this is the Tunguska crater. Everybody is looking for a big story.

 

[MeteorWayne]

Well, we can't tell yet.<br />If the researchers can drill thorugh the bottom next year (is it a coincidence? ) the evidence should be clear. <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>

 

[JonClarke]

It is the sort of thing that somebody would put into a grant application to try and tip the balance: <br /><br /><i>As the centenary of the Tunguska event approaches there are still many unreoslved issues. Our research proposal will address a number of these...</i><br /><img src="/images/icons/smile.gif" /><br />Jon <div class="Discussion_UserSignature"> <p><em>Whether we become a multi-planet species with unlimited horizons, or are forever confined to Earth will be decided in the twenty-first century amid the vast plains, rugged canyons and lofty mountains of Mars</em>  Arthur Clarke</p> </div>

 

[3488]

Hi Jon & MeteorWayne,<br /><br />It would be well worth the time & effort.<br /><br />If proven to be so, it would be a most important find.<br /><br />Hope that meteoritic fragments can be found.<br /><br />I have a feeling that jimcolyer is spoiling for an argument. He has been dissing comets<br />& now this.<br /><br />I for one will not give him the pleasure of one.<br /><br />Good night everyone.<br /><br />its late here.<br /><br />Andrew Brown. <div class="Discussion_UserSignature"> <p><font color="#000080">"I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before".</font> <em><strong><font color="#000000">Linda Morabito </font></strong><font color="#800000">on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.</font></em></p><p><font size="1" color="#000080">http://www.launchphotography.com/</font><br /><br /><font size="1" color="#000080">http://anthmartian.googlepages.com/thisislandearth</font></p><p><font size="1" color="#000080">http://web.me.com/meridianijournal</font></p> </div>

 

[alokmohan]

Eye witness ?In what sense?

 

[MeteorWayne]

There were a number of (fortunately for them) distant eyewitnesses to the event. Several knocked off their feet from hundreds of km away, IIRC. <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>