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Nick
2001-Oct-30, 05:16 PM
A report from the beeb.

http://news.bbc.co.uk/low/english/sci/tech/newsid_1628000/1628806.stm

Nick

Moonpuppy
2001-Oct-30, 06:07 PM
Somebody on the Discovery Channel actually did a scale-model demonstration of what probably happened. He pointed out how the worst damage was in a distinctive, butterfly-shaped pattern around a central point, and the trees in the exact center were still standing, although stripped of branches and foliage. The only way he could simulate this pattern was by showing how a meteorite, coming in at a fairly low angle, exploded just above the trees, flattening them and setting the forest aflame but leaving no crater. Can't recall the scientist's name.

Argos
2001-Oct-31, 10:34 AM
Excuse-me you all, but I didn't see this thread and ended up putting another one regarding the same subject. I hope BA will delete it.

Still, I'd like to point out that, according to my records, the first expedition to the spot of the fall, led by russian mineralogist Leonid Kulik (1883-1942) was set in 1921, not in 1930, as the article states.

Argos
2001-Oct-31, 12:14 PM
... The only way he could simulate this pattern was by showing how a meteorite, coming in at a fairly low angle, exploded just above the trees, flattening them and setting the forest aflame but leaving no crater. Can't recall the scientist's name.


The Czech astronomer L. Kresák studied a similar phenomenon, which occurred in 1974 in Sumawa, Czechoslovakia, when a fireball was registered by the all-sky cameras. The meteoroid body of that fireball must have had 200 metric tons when it penetrated the atmosphere, at 25 km/s, having been completely destroyed in 3 sec. The main luminous emissions occurred between 73 and 61 km altitude. A single fragment penetrated as deep as 55 km.

An analogous phenomenon was caught on film by an American team in October, 1969, in Ojarks. Its weight was estimated in 35 metric tons. When it reached 22 km of altitude it disintegrated into two balls, provoking two major explosions which generated several shock waves.

Prior to the announcement of the current Italian research, it was believed that the Tunguska object penetrated the upper atmosphere at 35 km/s, getting to an altitude of 6 km. To rush its way down through the atmosphere the way it did, it must have been a very compact rock, similar to the condrite meteorites. Its disintegration, at 12 km/s generated a hot wave capable of burning people's clothes as far as 60 km, according to documented witnesses.

The Czech Kresák believed that the Tunguska impact was caused by remnants of the Encke's comet. His theory was seriously jeopardized by an American astronomer, Z. Sekanina, after a deep analysis of observations and reports of witnesses, as well as the analysis of Encke's trajectory. According to Sekanina, to connect the Tunguska impact with Encke's comet it would be necessary to rotate the node lines of the comet approximately 56 degrees. When he related the ratio between the apsis lines and Jupiter's orbit plane with the aphelion distance of all the short period comets, Sekanina concluded that the comet hypothesis had to be ruled out.



<font size=-1>[ This Message was edited by: Argos on 2001-10-31 09:57 ]</font>

Phobos
2001-Nov-01, 01:27 AM
Mystery solved huh?

What about this ? (http://www.thetimes.co.uk/article/0,,3-2001251300,00.html)

They may be correct, but there will always be other theories.

Jeff

brianok
2001-Nov-05, 02:32 PM
I remember reading that there was one recorded fatality caused by the blast, a trapper in the woods somehow broke his arm when he was caught in the shockwave and later died of an infection.

James
2001-Nov-06, 01:54 AM
On 2001-11-05 09:32, brianok wrote:
I remember reading that there was one recorded fatality caused by the blast, a trapper in the woods somehow broke his arm when he was caught in the shockwave and later died of an infection.


Brianok, you may believe where you got this from, but I would like to know your source for this. The reason why I'm saying this is because Siberia at the time had so little population and was spread over the whole of Siberia that no one invetigated the blast itself for about 25-30 years later. So, I'm just wondering on your source, is all.

brianok
2001-Nov-06, 03:28 PM
I don't remember exactly where I read that. However I have found 4 websites which mention fatalities at Tunguska in 1908:


http://www.psi.edu/projects/siberia/siberia.html



http://www.oberlin.edu/library/sciencelib/geo117/group9/group9.html


http://www.tmeg.com/artifacts/tunguska/tunguska.htm



http://www.au.af.mil/au/2025/volume3/chap16/v3c16-2.htm

<font size=-1>[ This Message was edited by: brianok on 2001-11-06 13:02 ]</font>

brianok
2001-Nov-06, 05:40 PM
And I also found this article from the London Times saying the blast could have been volcanic:


SATURDAY JULY 21 2001

Siberia blast was 'volcanic blowout'

BY GILES WHITTELL IN MOSCOW

THE cause of a massive explosion over central Siberia that has remained one of the great mysteries of modern science, was a “volcanic blowout” of ten million tonnes of natural gas, a noted German physicist has claimed.
The eruption over the Tunguska plateau one summer morning 93 years ago has long been explained as the impact of the biggest meteorite to hit Earth since prehistoric times. It scorched nearly 1,000 sq miles of forest, incinerated entire colonies of reindeer and sent elderly men 200 miles away running for the bathhouse to be clean for their impending deaths.

For the past half-century the “Tunguska event” has been explained as an incoming meteorite or comet exploding in the upper atmosphere with the force of 1,000 Hiroshima bombs. However, it left no cosmic debris or crater, forcing even experts to admit that its cause was one of the great mysteries of modern science.

That may be about to change: 17 factors, including the patterns of tectonic faults and fallen trees in the area, suggest that the explosion had nothing to do with outer space, but was caused by gas forced upwards from the planet’s molten core, Wolfgang Kundt, Professor of Astrophysics at the University of Bonn, writes in August’s issue of the journal Current Science.

The “outgassing” may also have created, in a few earth-shaking minutes, a geological structure close to the surface of the Earth known as a kimberlite after the legendery diamond reserves found in the 19th century near the South African town of Kimberley, Professor Kundt writes.

“If they find that, as is indicated, it would turn Siberia into a rich industrial country,” he told The Times, dismissing the comet and meteorite theories as pseudo-science. “If good physicists had been involved from the start this problem would never have occurred,’ he said. “As it was (the early study of the Tunguska phenomenon) was left to geophysicists and geologists with no knowledge of extraterrestial bodies.”

The first outsider to visit Tunguska was neither a physicist nor a geophysicist, but a goldsmith named Suzdalev, who arrived in 1910 and swore the locals to silence about what he found. They obeyed, and it is unknown whether he left with a fortune in diamonds or nothing at all.

The next expedition was in 1927, when Leonid Kulik, a Russian geologist, observed a stunning radial pattern of thousands of trees felled by the blast, their blackened trunks pointing to an epicentre in the middle of a 250 million year-old volcanic crater at the junction of seismic faultlines.

Witness accounts from 1908, throughout the region were plentiful, but contradictory. They spoke of fireballs, twin columns of flame and trails of fire from several directions. There were also reports of eerie lights in the night sky before and after June 30, strong enough to read a newspaper by and visible as far away as Western Europe.

Amateurs have explained these accounts with theories about black holes, “anti- matter bullets” and, most popular of all, an exploding spaceship that was the subject of a best-selling Soviet book, Guest From Space.

Two costly expeditions by the University of Bologna since the Soviet collapse have focused on meteorites. They claim to have found microscopic traces of space dust in spruce resin to support the view that the blast was caused by a stony meteor 200ft wide approaching at a 45-degree angle and exploding four miles above the Earth. However, such a meteorite cannot account for 12 conical holes in the ground near the epicentre and would have felled the trees in a parallel pattern, Professor Kundt insists.

Andrei Olkhovatov, a Russian scientist who supports many of his findings, says that a meteor 200ft across would have left at least 100,000 tonnes of debris along its approach path. “But the question arises, where are the remnants?” he asked. “Nowhere, nothing after decades of detailed research.”

Ravi Pinjala
2001-Nov-10, 03:38 PM
I found a theory that's WAY out there, while doing research for school.

http://www.frank.germano.com/tunguska.htm

revenant
2001-Dec-17, 01:46 AM
the tesla theory seems quite plausible /phpBB/images/smiles/icon_wink.gif

GrapesOfWrath
2002-Sep-03, 04:54 PM
On 2001-11-06 12:40, brianok wrote:
SATURDAY JULY 21 2001

Siberia blast was 'volcanic blowout'

BY GILES WHITTELL IN MOSCOW

THE cause of a massive explosion over central Siberia that has remained one of the great mysteries of modern science, was a “volcanic blowout” of ten million tonnes of natural gas, a noted German physicist has claimed.

A similar explanation: New Hypothesis Of The Tunguska Explosion (http://www.spacedaily.com/news/deepimpact-02q.html
), where a geologist Vladimir Epifanov claims that "that the reason for the explosion could have been a powerful fluid jet suddenly shot up from the depth of the planet."

Wiley
2002-Sep-03, 06:56 PM
A similar explanation: New Hypothesis Of The Tunguska Explosion (http://www.spacedaily.com/news/deepimpact-02q.html
), where a geologist Vladimir Epifanov claims that "that the reason for the explosion could have been a powerful fluid jet suddenly shot up from the depth of the planet."


The link is not working for me. Should it be this (http://www.spacedaily.com/news/deepimpact-02q.html)?