Tunguska!
The Tunguska Event, Sometimes called the Tunguska Explosion, occurred near the Tunguska River in what is now Krasnoyarsk Krai, in Russia, at 7:40 AM on June 30, 1908.
Eyewitnesses described a diffuse bright ball two or three times larger than the sun but not as bright; the trail was a "fiery-white band." The giant fireball appeared to race across the night sky.
It exploded with the force of 1,000 Hiroshima bombs, killing herds of reindeer and scorching hundreds of miles of trees, knocking them down in an outward radial pattern. The night sky had an orange glow as far away as Western Europe. But the only other outside proof that something happened was a small quiver on a seismograph 1,000 miles away in the city of Irkutusk. The Earth itself was largely untouched. A bullet had grazed its scalp.
It took 19 years for Russian mineralologist Leonid Kulik’s scientific party to come to the site. Their first impressions were that a massive fire, or fires, had broken out all at once, the impact of the heat-winds knocking down trees in a vast circle. Except for the initial devastation at ground-zero, other buildings and structures in the knock-down area were left untouched. Only the trees were scorched and flattened - but for a few, strangely, that stood stripped of foliage and limbs, but upright, at ground-zero.
Over the next 14 years. Kulik made four more expeditions to Tunguska, seeking proof of meteorite activity. No crater or meteor-iron or glazed earth was ever found. Kulik died as a PoW in 1942, leaving behind the best extant catalogue of Tunguska Event photographs.
But what is it?
Theories advanced over the years have suggested that the Tunguska event was either a comet, a meteorite, a UFO, a Biblically prophesied event, a black hole or a wormhole interacting with Earth’s atmosphere, a piece of antimatter, or, more recently, a white hole.
The UFO Theory
In 1946, a Soviet engineer and army colonel wrote a short story explaining that the destruction at Tunguska could only have been from a nuclear bomb, and that since humans did not have that capability in 1908, it must have been an exploding spaceship. The book became popular in the Soviet Union and a group of scientists decided to find out if it were true. There would still be measurable levels of radiation. They searched for two years but found nothing.
The popularity of their work showed that the writers had tapped into a preexisting notion. With the advent of the Space Race, and the growing fascination with potential alien races, the idea of Tunguska as a cosmic or alien event was quickly seized upon, especially given that nobody was physically harmed. Many considered this to be a sign of benevolent intelligence. Others considered it a modern-day Tower of Bab-el, sent as a merciful warning to a largely uninhabited area of the world.
Later expeditions to the area found 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, hinting that they were of extraterrestrial origin - but hardly an intelligent one.
The alien-technology debate remained in the news even unto October 8, 2004, when Russian newspaper Pravda reported that:
Members of the scientific expedition of the Siberian state foundation Tunguska Space Phenomenon say they have managed to uncover blocks of an extraterrestrial technical device. The space body, which was later called the Tunguska meteorite, fell down on Earth on June 30th 1908, 65 kilometers off the Vanavara settlement, the Evenkiya republic.[6]
The Tunguska Event, meanwhile, enjoys occasional revivals in UFO folklore and works of science-fiction. While we the annotator of these notes would thoroughly enjoy meeting a real live alien intelligence, this wasn't a representative of the species.
But really now…
In scientific circles, the leading explanation for the explosion is the pre-impact airburst of a meteoroid 6 to 10 kms (4-6 mi) above Earth's surface. Although the meteor or comet is considered to have burst prior to hitting the surface, this event is still referred to as an impact event. The energy of the blast was estimated to be between 10 and 20 megatons of TNT. The explosion felled an estimated 80 million trees over 2,150 square kms (830 sq mi).
However, except for ground-zero, which was simply scrubbed of life and has made a slow recovery, no unusual nuclear radiation had been detected. Some suggest that this would be expected in a non-impact meteoric explosion, but recent work shows that given sufficiently high speed of expansion, nuclear fusion, and not fission, may have occurred, leaving behind only a weak and short-lasting rise in radiation. The only known contamination in the area comes from the nearby Russian Kosmodrome, which routinely scatters debris from shuttle landings, experiments and other activities in the uninhabited area.
The Tunguska event is the largest impact event in recent history. An explosion of this magnitude had the potential to devastate large metropolitan areas had it occurred over a large city. This possibility has helped to spark discussion of asteroid deflection strategies.
Current Studies
In June of 2007 it was announced that scientists from the University of Bologna had identified a lake in the Tunguska region as a possible impact crater from the event. Lake Cheko is a small bowl shaped lake approximately 8 kilometers north-north-west of the epicenter. The hypothesis has since been challenged by other impact crater specialists, who claim that the position of the lake makes the claim implausible, and also that there is sufficient local proof that the lake existed before the Tunguska Event.
Tunguska Encore
Other Tunguska-esque events have been reported over the years, with 10 out of the suggested 12 taking place in the Northern Hemisphere.
Sources:
[1] http://www.barilochenyt.com.ar/tunguska.htm
[2] http://www.dailygalaxy.com/my_weblog/impact_events/
[3] http://omzg.sscc.ru/tunguska/
[4] http://en.wikipedia.org/wiki/Tunguska_event
[5] http://www.nso.lt
[6] http://english.pravda.ru/science/19/94/378/13705_tunguska.html
Eyewitnesses described a diffuse bright ball two or three times larger than the sun but not as bright; the trail was a "fiery-white band." The giant fireball appeared to race across the night sky.
It exploded with the force of 1,000 Hiroshima bombs, killing herds of reindeer and scorching hundreds of miles of trees, knocking them down in an outward radial pattern. The night sky had an orange glow as far away as Western Europe. But the only other outside proof that something happened was a small quiver on a seismograph 1,000 miles away in the city of Irkutusk. The Earth itself was largely untouched. A bullet had grazed its scalp.
It took 19 years for Russian mineralologist Leonid Kulik’s scientific party to come to the site. Their first impressions were that a massive fire, or fires, had broken out all at once, the impact of the heat-winds knocking down trees in a vast circle. Except for the initial devastation at ground-zero, other buildings and structures in the knock-down area were left untouched. Only the trees were scorched and flattened - but for a few, strangely, that stood stripped of foliage and limbs, but upright, at ground-zero.
Over the next 14 years. Kulik made four more expeditions to Tunguska, seeking proof of meteorite activity. No crater or meteor-iron or glazed earth was ever found. Kulik died as a PoW in 1942, leaving behind the best extant catalogue of Tunguska Event photographs.
But what is it?
Theories advanced over the years have suggested that the Tunguska event was either a comet, a meteorite, a UFO, a Biblically prophesied event, a black hole or a wormhole interacting with Earth’s atmosphere, a piece of antimatter, or, more recently, a white hole.
The UFO Theory
In 1946, a Soviet engineer and army colonel wrote a short story explaining that the destruction at Tunguska could only have been from a nuclear bomb, and that since humans did not have that capability in 1908, it must have been an exploding spaceship. The book became popular in the Soviet Union and a group of scientists decided to find out if it were true. There would still be measurable levels of radiation. They searched for two years but found nothing.
The popularity of their work showed that the writers had tapped into a preexisting notion. With the advent of the Space Race, and the growing fascination with potential alien races, the idea of Tunguska as a cosmic or alien event was quickly seized upon, especially given that nobody was physically harmed. Many considered this to be a sign of benevolent intelligence. Others considered it a modern-day Tower of Bab-el, sent as a merciful warning to a largely uninhabited area of the world.
Later expeditions to the area found 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, hinting that they were of extraterrestrial origin - but hardly an intelligent one.
The alien-technology debate remained in the news even unto October 8, 2004, when Russian newspaper Pravda reported that:
Members of the scientific expedition of the Siberian state foundation Tunguska Space Phenomenon say they have managed to uncover blocks of an extraterrestrial technical device. The space body, which was later called the Tunguska meteorite, fell down on Earth on June 30th 1908, 65 kilometers off the Vanavara settlement, the Evenkiya republic.[6]
The Tunguska Event, meanwhile, enjoys occasional revivals in UFO folklore and works of science-fiction. While we the annotator of these notes would thoroughly enjoy meeting a real live alien intelligence, this wasn't a representative of the species.
But really now…
In scientific circles, the leading explanation for the explosion is the pre-impact airburst of a meteoroid 6 to 10 kms (4-6 mi) above Earth's surface. Although the meteor or comet is considered to have burst prior to hitting the surface, this event is still referred to as an impact event. The energy of the blast was estimated to be between 10 and 20 megatons of TNT. The explosion felled an estimated 80 million trees over 2,150 square kms (830 sq mi).
However, except for ground-zero, which was simply scrubbed of life and has made a slow recovery, no unusual nuclear radiation had been detected. Some suggest that this would be expected in a non-impact meteoric explosion, but recent work shows that given sufficiently high speed of expansion, nuclear fusion, and not fission, may have occurred, leaving behind only a weak and short-lasting rise in radiation. The only known contamination in the area comes from the nearby Russian Kosmodrome, which routinely scatters debris from shuttle landings, experiments and other activities in the uninhabited area.
The Tunguska event is the largest impact event in recent history. An explosion of this magnitude had the potential to devastate large metropolitan areas had it occurred over a large city. This possibility has helped to spark discussion of asteroid deflection strategies.
Current Studies
In June of 2007 it was announced that scientists from the University of Bologna had identified a lake in the Tunguska region as a possible impact crater from the event. Lake Cheko is a small bowl shaped lake approximately 8 kilometers north-north-west of the epicenter. The hypothesis has since been challenged by other impact crater specialists, who claim that the position of the lake makes the claim implausible, and also that there is sufficient local proof that the lake existed before the Tunguska Event.
Tunguska Encore
Other Tunguska-esque events have been reported over the years, with 10 out of the suggested 12 taking place in the Northern Hemisphere.
Sources:
[1] http://www.barilochenyt.com.ar/tunguska.htm
[2] http://www.dailygalaxy.com/my_weblog/impact_events/
[3] http://omzg.sscc.ru/tunguska/
[4] http://en.wikipedia.org/wiki/Tunguska_event
[5] http://www.nso.lt
[6] http://english.pravda.ru/science/19/94/378/13705_tunguska.html