To: Graybeard58

No it was June 30, 1908.

---Which is exactly what I said.

Weird rusting sounds could be heard.

I've often wondered what kind of sound rust makes.
////////////////
likely there's a typo there and they meant "rustling"

Washington fireball – panel 1/2

Major News for 4 June 2004

Washington fireball

The Seattle Times wrap today on yesterday morning's fireball over Washington state tells that the explosion was picked up by 80 University of Washington (UW) seismic stations, registering "magnitude 1.6 on the earthquake scale. It reports that UW seismologist Steve Malone "was able to use the instrument readings to pinpoint the site of the explosion: About six miles northeast of the town of Snohomish and 26 miles above ground... 'And it looks like it entered the atmosphere at a fairly steep angle.'" The paper also has a compilation of witness reports, and quotes one eyewitness as saying he would pay "to see that again."

The Seattle Post-Intelligencer today cites Bill Steele of the UW Pacific Northwest Seismograph Network (PNSN) with reporting that "The meteor appears to have exploded about 27 miles [43 km.] above and 6.4 miles northeast of the city of Snohomish." It quotes him as saying "we saw only a point source (a single explosion) . . . rather than the sonic-boom kind of sound wave that comes as an object rapidly enters the

atmosphere," thus a conclusion that the meteor's entry was steep.

Both papers have images from several security cameras at Harborview Medical Center in Seattle that caught the flash of the fireball, but not the fireball itself.

PNSN has a news item from yesterday that links to the seismograph "webicorder" event readings. It is noted that, although eyewitnesses reported seeing it from eastern Washington state and further east, the fireball did not leave "a sonic trail on our eastern Washington stations," which is further evidence for a steep entry.

Ed Majden tells A/CC that his was the only all-sky camera in the region that was in service yesterday morning. He points out that the Canadian Space

<< continued from panel 1

Administration Meteorites and Advisory Committee (MIAC) has a catalog of North American cameras with location and status.

Editor & Publisher has a follow-up report today, "Radio Station Tries to Track Down Source of Bogus AP 'Meteor Crash' Report." That the hoax hasn't completely died can be seen in a report today at KATC-TV in Lafayette, Louisiana.

The Cascadia Meteorite Lab at Portland State University has posted a fireball report. It says sonic booms were heard in Portland, Oregon, and "A 'burning sulfur smell' was reported in Chehalis," Washington (about 100 miles south-southwest of Snohomish). And it and an article at the Oregonian say that witness reports indicate that the object traveled "west to east towards the Centralia-Chehalis area." Dick Pugh from the lab told the paper that a driver south of Olympia (well southwest of Snohomish and north of Chehalis) "saw the meteor break up in the southern sky," while people saw it to the north from Vancouver, Washington, across the river from Portland.

Among other local eyewitness reports at the Olympia Olympian today is one from Stardust comet mission Principal Investigator Don Brownlee: He "said his son saw the bright light and then the whole family heard the sonic boom from inside their houseboat. 'We heard this incredible noise that sounded like a truck landing on the dock.'"

The Peninsula Daily News in Port Angeles, Washington also has local reporting today, and says that "In Neah Bay, a security camera overlooking the Makah Marina caught two flashes of light followed by a loud noise four minutes and 33 seconds later," with "a small flash . . . and then a bright light."

The Bremerton Sun has posted a compilation of witness reports, and says in an article today that the event overloaded the local 911 call center, with "80%" of the calls inappropriately from people just wanting to know what had happened.

They find the beaches too crowded and the service stinks.

here's an interesting set of articles that cover different meteorite strikes over the last couple years.

thanks

It might be impossible to find a 60 ton meteorite. First, it's not very big. Second, it might have struck the ground lightly so there was no crater and the meteorite is just partly buried. Third it might have struck a pond and is not visible at all.

Kersplush!

"If the meteorite had a greater speed, for example, 25 kilometers per hour, it is possible to assume that there were only several kilograms left of the space object."

Chances are it'd never had caught up with the earth - unless it just simply got in the way.

40 miles square is always 1600 square miles.

That's okay for knotted rope surveying, but we need to throw the geoid into the mix these GPS days.

the tunguska siberian strike of 1908--or there about-- left a devastation path in a butterfly pattern. but this was only learned much later.

Like a radio antenna emission pattern? Linking to the associated electrical phenomena.

Tunguska event

From Wikipedia, the free encyclopedia.

The Tunguska event is a mysterious aerial explosion that occurred near the Tunguska River in what is now Evenkia, in Siberia. It took place at 7:17 AM on June 30, 1908. The blast felled an estimated 60 million trees over 2,150 square kilometres. Witnesses observed a huge fireball, almost as bright as the Sun, plunging across the Siberian sky, terminating in a huge explosion that registered on seismic stations all across Eurasia. The size of the blast was later estimated to be between 10 and 15 megatons.

Table of contents[]

1 History

1.1 Early expeditions
1.2 Later expeditions

2 Theories

2.1 Comet impact
2.2 Asteroid impact
2.3 Electromagnetic effect

3 Fictional explanation

4 See also

5 External links and references

[edit]

History

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Early expeditions

Surprisingly, there was little scientific curiosity about the impact at the time, and due to the subsequent occurrence of war, revolution, and civil war in Russia, it wasn't until the 1920s that anyone performed a serious investigation of what had happened in Siberia in 1908.

In 1921, the Russian mineralogist Leonid Kulik visited the Podkamennaya Tunguska River basin as part of a survey for the Soviet Academy of Sciences. Locals told him of the great blast, of huge stretches of forest being flattened, of people being blown over by the shock.

The reports were basically consistent with each other, and Kulik was able to persuade the Soviet government to fund an expedition to the Tunguska region. His group reached the "ground zero" of the "event" in 1927. Much to their surprise, there was no crater, just a great region of scorched trees about 50 kilometers across. The trees pointed away from the center of the event, with a few still bizarrely standing upright at ground zero, their branches and bark stripped off.

Over the next ten years, there were three more expeditions to the area, and none of them discovered anything much different from what Kulik and his people had found. Kulik found a little "pothole" bog that he thought might be the crater, but after a laborious exercise in draining the bog, he found there were old stumps on the bottom, ruling out the possibility that it was a crater.

Kulik did manage to arrange an aerial photographic survey of the area in 1938, a few years before his death as a Red Army officer in the Great Patriotic War. The aerial survey revealed that the event had knocked over trees in a huge butterfly-shaped pattern that provided information on the direction of the object's motion. It found no crater, despite the large amount of devastation.

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Later expeditions

Soviet experiments performed in the mid-1960s with model forests and small explosive charges slid downward on wires that duplicated this pattern suggested that the 1908 object had approached at an angle of roughly 30 degrees from the ground and 115 degrees from north, and exploded in mid-air.

Expeditions sent to the area in the 1950s and 1960s did find microscopic glass spheres in siftings of the soil. Chemical analysis showed that the spheres contained high proportions of nickel and iridium, which are found in high concentrations in meteorites, and indicated that they were of extraterrestrial origin. However, even this clue could not pin down the nature of the object precisely.

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Theories

The precise cause of the Tunguska event remains unknown. In scientific circles, the leading explanation for the blast is the impact of a meteorite. A related suggestion is that a meteorite exploded just above the Earth's surface. Whether the meteorite was of cometary or asteroidal origin is still a matter of controversy. Whatever the original cause of the event is, much of the data supports that the cause resembled a nuclear explosion.

In the absence of an obvious explanation, numerous alternative theories have been offered, such as a small black hole passing through the Earth, an impact from a piece of antimatter, and even the catastrophic destruction of a nuclear-powered alien spacecraft. However, there has not been much evidence for these exotic ideas, and simpler theories are available.

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Comet impact

In 1930, the British astronomer F.J.W. Whipple suggested that the Tunguska event was produced by the impact of a small comet. A cometary meteorite, being composed primarily of ices and dust, could have completely vaporized by the impact with the Earth's atmosphere, leaving no obvious traces. The idea of a comet impact was supported by the "skyglows" observed across Europe for several evenings after the impact, apparently caused by dust that had been dispersed across the upper atmosphere. In addition, chemical analyses of the area have showed it to be enriched in cometary material.

The comet idea remained popular for over 50 years, with some astronomers speculating that it might have been a piece of the short-period Comet Encke. Materials from Encke appear to make up the stream of space debris that create the Beta Perseid meteor shower, and the Tunguska event coincided with a peak in that shower.

In 1983, an astronomer named Zdenek Sekanina, working the NASA Jet Propulsion Laboratory, published a paper that undermined the comet theory. Sekanina pointed out that eyewitness accounts and other evidence point only to one explosion, and that the object passed through the atmosphere at a shallow angle, remaining intact to an altitude of 8.5 kilometers. A body composed of ice and gases could not have travelled such a distance without disintegrating. Proponents of the comet theory have suggested, in reply, that the object might have been an extinct comet with a stony mantle that allowed it to penetrate the atmosphere.

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Asteroid impact

An alternative explanation is that the Tunguska meteorite was a stony asteroid. In 2001, Farinella, Foschini, et al. released a study suggesting that the object had arrived from the direction of the asteroid belt, working from eyewitness accounts, seismic records, and samples from a 1999 expedition to the area.

The chief difficulty in the asteroid theory is that a stony object should have produced a large crater where it struck the ground, but no such crater has been found. It has been hypothesized that the passage of the asteroid through the atmosphere caused pressures and temperatures to build up to a point where the asteroid abruptly disintegrated in a huge explosion. The destruction would have had to be so complete that no remnants of substantial size survived, and the material scattered into the upper atmosphere during the explosion would have caused the skyglows. However, it remains an open question why the meteorite should have disintegrated so abruptly.

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Electromagnetic effect

The Tunguska Event does appear to be similar to magnetic storms that occur after thermonuclear explosions (such as from a nuclear weapon) in the stratosphere. Anomalous concentrations of electrical energy in the region could have produced an explosive releases of energy. Electromagnetic fireballs, spherical plasmoids, and ball lightning have been reported to exhibit the same phenonomena. Other plasma and geomagnetic theories have been formed. V. K. Zhuravlev and A. N. Dmitriev, in 1984, proposes a "heliophysical" model that explains the Tunguska event as a result of plasmoids ejected from the Sun. Valeriy Buerakov also develops an independent model of an electromagnetic "ball" that could deliver such force.

Some have suggested that the Tunguska explosion may have been the result of an experiment by Nikola Tesla at Wardenclyffe from a 1908 article in Wireless Telegraphy and Telephone. In the article, Tesla states that he would be able to direct electrical energy to any point on the globe. The mechanism and inner workings behind Tesla's Wardenclyffe facility are not well understood. Tesla had stated it was an evolution of his magnifying transformer and could concentrate electromagnetic energy output over long distances. Tesla, in March 1907, did state that he was capable of "projecting wave energy" and, in April 1908, Tesla expounds on the possiblities of "direct application of electrical waves without the use of aerial engines or other implements of destruction".

It is not certain if Tesla ever used the Wardenclyffe facility for this manner. Reports of 1908 have Tesla testing the facility during Robert Peary's second North Pole expidition. Reportedly, Tesla operated the Wardenclyffe facility to send enormous power to an area west of the Peary expedition. Tesla's associate, George Scherff, witnessed these evernts at Wardenclyffe Tower. During the test, Wardenclyffe tower emitted a faint soft glow and disintegrated an owl that passed in front of it. Analysis of Peary's position and Tunguska deviates by 2 degrees on a straight line from the Wardenclyffe facility. Shortly afterward, Tesla stopped speaking of this type of possibility for Wardenclyffe-type installations (though he does introduce the concept of teleforce).

[edit]

Fictional explanation

In the fictional Star Trek universe, the Tunguska event is explained as an attempt to save Earth. Apparently, an alien race saved humanity by deflecting an incoming meteor that would have hit Europe. The remnants of the meteor fell down to Siberia.

[edit]

External links and references

Università di Bologna, Dept. of Physics. "Tunguska (http://www-th.bo.infn.it/tunguska/)"
Earth Impact. "The Tunguska event (http://www.s-d-g.freeserve.co.uk/tunguska.html)".
Farinella P., Foschini L., et al Probable asteroidal origin of the Tunguska Cosmic Body (http://www-th.bo.infn.it/tunguska/aah2886.pdf), Astronomy and Astrophysics 377, 1081-1097 (2001) : (PDF) - Abstract (http://aanda.u-strasbg.fr:2002/articles/aa/abs/2001/39/aah2886/aah2886.html)
Zhuravlev, Victor, "Geomagnetic effects as one aspect of the Tunguska event (http://www.galisteo.com/tunguska/docs/zhur_us.html)", International Workshop Tunguska. 1996. Bologna, Italy.
Florenskiy, K. P., "Preliminary results from the 1961 combined Tunguska meteorite expedition (http://abob.libs.uga.edu/bobk/tungmet.html)" Meteoritica, Vol. XXIII. 1963.
Silagadze, Z.K., "Tunguska genetic anomaly and electrophonic meteors (http://arxiv.org/pdf/astro-ph/0311337)". Budker Institute of Nuclear Physics, Novosibirsk, Russia. (Arxiv.org - PDF)
Zhuravlev, V. K. and F. Y. Zigel. "The Tunguska Miracle". Ekaterinburg. "Basko" Publishing House, 1998
K.G. Ivanov. "Geomagnetic effect of Tunguska explosion". International Conference: 90 Years of Tunguska Event. GAIS. Moscow, Russia. 1998.
A. N. Dmitriev, and V. K. Zhuravlev. "Tunguska phenomenon of 1908 as a form of Solar-Terrestrial interactions". Novosibirsk, USSR Academy of Science. Siberia. Branch Geology. Geophysisc Institute, 1984.
Kalmick, Dan and Thomas Shoujen Kuo, Department of Nuclear Engineering, Freshman Seminar Series, "Wardenclyffe and Tunguska (http://www.nuc.berkeley.edu/dept/Courses/E-24/E-24Projects/Kalmick/E-24-files/ppframe.htm)". (J. Vujic and V. Oklobdzija, Professors) - Outline (http://www.nuc.berkeley.edu/dept/Courses/E-24/E-24Projects/Kalmick/E-24-files/outlinee.htm)
Nichelson, Oliver, "Tesla's Wireless Power Transmitter and the Tunguska Explosion of 1908 (http://www.frank.germano.com/tunguska.htm)". American Fork, Utah. 1995.
Nichelson, Oliver, "Tesla Wireless and the Tunguska Explosion (http://prometheus.al.ru/english/phisik/onichelson/tunguska.htm)". Harvard.edu
Taylor, Alan, "Tunguska - A Tesla Experiment Gone Wrong (http://www.galisteo.com/tunguska/bbs/messages/110.html)?".

Modern impact events

The most significant recorded impact in recent times was the Tunguska event, which occurred at Tunguska in Russia, in 1908. But although the Tunguska event was both spectacular and unparalleled in any historical record, it no longer seems as unique and unusual as it once did. We now know that Earth impacts, fairly big ones, are happening all the time.

The late Eugene Shoemaker of the US Geological Survey came up with an estimate of the rate of Earth impacts, and suggested that an event about the size of the nuclear weapon that destroyed Hiroshima occurs about once a year. Such events would seem to be spectacularly obvious, but they generally go unnoticed for a number of reasons: the majority of the Earth's surface is covered by water; a good portion of the land surface is uninhabited; and the explosions generally occur at relatively high altitude, resulting in a huge flash and thunderclap but no real damage.

Some have been observed, such as the Revelstoke fireball of 1965, which occurred over the snows of northern Canada. Another fireball blew up over the Australian town of Dubbo in April 1993, shaking things up a bit but causing no harm.

On the dark morning hours of January 18, 2000, a fireball exploded over the town of Whitehorse in the Canadian Yukon at an altitude of about 26 kilometers, lighting up the night like day and bringing down a third of the Yukon's electrical power grid, due to the electromagnetic pulse created by the blast. The meteor that produced the fireball was estimated to be about 4.6 meters in diameter and with a weight of 180 tonnes.

A particularly interesting fireball was observed moving north over the Rocky Mountains from the US Southwest to Canada on August 10 1972, and was filmed by a tourist at the Grand Teton National Park in Wyoming with an 8-millimeter color movie camera. The object was in the range of size from a car to a house and should have ended its life in a Hiroshima-sized blast, but there was never any explosion, much less a crater. Analysis of the trajectory indicated that it never came much lower than 58 kilometers of the ground, and the conclusion was that it had grazed Earth's atmosphere for about 100 seconds, then skipped back out of the atmosphere to return to its orbit around the Sun.

Many impact events occur without being observed by anyone on the ground. Between 1975 and 1992, American missile early warning satellites picked up 136 major explosions in the upper atmosphere.

The Tunguska event was about a thousand times more powerful than such events. Shoemaker estimated that one of such magnitude occurs about once every 300 years. This is not a long interval even by historical standards, and it is a somewhat nerve-wracking question to consider when the next "Big One" will be, and more to the point, where.

The 1994 impact of Comet Shoemaker-Levy 9 with Jupiter also served as a "wake-up call", and astronomers responded by starting programs such as Lincoln Near-Earth Asteroid Research (LINEAR), Near-Earth Asteroid Tracking (NEAT), Lowell Observatory Near-Earth Object Search (LONEOS) and several others which have drastically increased the rate of asteroid discovery. Many objects undoubtedly still remain undetected, however.

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External links

Earth impacts (http://www.vectorsite.net/taimpact.html)
Earth Impact Database (http://www.unb.ca/passc/ImpactDatabase/index.html)
Earth Impact Effects Program (http://www.lpl.arizona.edu/impacteffects/)

[edit]

Tunguska event

From Wikipedia, the free encyclopedia.

History

Early expeditions

Later expeditions

Theories

Comet impact

Asteroid impact

Electromagnetic effect

Fictional explanation

See also

External links and references

Modern impact events

External links

Further Reading