Hazards from Space .... including a relook at the Tunguska event

29 Sep 2010

At www.physorg.com/print204826766.html we learn that the Panoramic Survey Telescope has discovered an asteroid that will come within 4 million miles of the Earth in mid-October (a couple of weeks to go). It's a bit early for 2012 predictions and the object is just 150 feet in diameter. It will not strike the Earth, we are informed - and just as well, but scientists suspect there are many more of them under a mile across that have not yet been discovered - and you never know.

At www.sciencedaily.com/releases/2010/09/100923081902.htm a Google Earth search for craters found one in the Egyptian desert (in 2008), the Kamil crater. A 1.3 metre ten ton chunk of iron drilled a hole 16m deep and 45m wide - at some point within the last 10,000 years. It would have generated a fireball and plume visible over 1000km, or more. As the crater is extremely pristine in appearance it is potentially less than a few thousand years in age according to ESA scientists.

This brings me to a paper by EM Drobyshavski, 'Tunguska-1908 and similar events in light of the New Explosive Cosmogony of minor bodies' and can be printed out (whole article) from http://dl.dropbox.com/u/2268163/Explosion%20Cosmogony.pdf (the Russian Academy of Sciences in St Petersburg). The Tunguska object was probably a piece detached from a short period cometary nuclei that detonated in the upper atmosphere while on a tangential trajectory - and most of the nuclei was deflected away from the Earth back into space. However, the detonation in the atmosphere was enough to cause the scorching and felling of trees in a butterfly pattern. The same nuclei is destined to interact with the Earth again - at some indeterminate point in the future. One reason he suspects the object was deflected is that Tunguska did not result in a major climatic downturn - a sharp drop in global temperature. This would be expected if there was an impact - that ejected dust and debris upwards. Does this mean Mike Baillie is right and low growth tree ring events in the past may have a connection with cosmic events - such as those expected in the Clube and Napier model?

In addition, Drobyshavski remarks on the YD boundary event - and the lack of a crater (one of the big criticisms of the idea). He says there is a gap in our knowledge concerning cometary bodies of between 200 to 500m in diameter, and possibly even those 1km wide, as they might not actually create a crater as the detonation induced expansion of nucleic material would spread over the surface and any cratering would be shallow and virtually indiscernible over the course of time. He further explains two bowl cratering. This came up on In the News a few weeks ago as there was a prominent example of the process in Ukraine, and it has been discussed on the forum at www.thunderbolts.info in which it was denied they could possibly have an impact connection - but nature can throw up all kinds of surprises. According to Drobyshavski they can be explained by a partial explosion of a comet nuclei - the deeper one by the impact of an unexploded section of the nuclei and the surrounding shallow plate like crater from the hypervelocity impact of the exploding section of the nuclei, detonating at high altitude.

Drobyshavski suggests the YD boundary event crater could be in Kazakhstan - suitably a double crater as above. In the 1980s Izokh said this particular crater was some 10,000 years of age, very near the YD boundary event, and he even suggested a connection with the Late Pleistocene catastrophic events There is in this an anomaly - how could an impact in Kazakhstan generate wildfires in North America (and possibly in South America too)? However, the landscape fires may not have burnt entire continent wide regions but smaller sections of forest and grassland may have been ignited as a result of cometary debris falling along the trajectory of the object in question. Napier of course explained the lack of a crater by the nature of the material interacting with the Earth - one of the swarms of material ejected from the progenitor comet as a result of machining, forming dense streams of dust and small pieces of cometary material that clogged up the atmosphere of the earth and created fires on the surface etc. It did not involve a huge impact in his scenario and therefore a large crater was unneccessary.