Tunguska meteorite: a warning from outer space

MOSCOW. (Alexander Bagrov) - Almost a century ago, on 17 June 1908, a massive explosion occurred near the Podkamennaya Tunguska River, in what is now Russia's Krasnoyarsk Territory, Central Siberia.

The residents of the Vanavara trading post, 65 kilometers ( 40 miles) south of the blast site, later claimed that the ground trembled violently when attacked by a huge ball of fire, followed by a terrible storm that destroyed everything in its wake.

The explosion was most likely caused by the airburst of a large meteoroid or comet fragment at an altitude of 5- 10 kilometers (3- 6 miles) from the Earth's surface. Studies have yielded varying estimates for the object's size, with most experts agreeing that it measured several dozen meters in diameter.

Estimates of the energy of the blast range from 5 megatons to as high as 30 megatons of TNT, with 10-15 megatons being the most likely yield. The blast, about 1,000 times more powerful than the Hiroshima bomb, felled an estimated 80 million trees over 2,150 square kilkometers (830 square miles). The earthquake caused by the blast measured 5.0 on the Richter scale. The region has never completely recovered.

The Tunguska blast was the largest meteoroid impact in the Earth's recent history, and demonstrated the awesome destructive power of near-space objects. An explosion of the scale of the one in Tunguska could destroy large metropolitan areas. It is this possibility that has helped to spark discussion of asteroid deflection strategies.

Due to the rotation of Earth, if the collision had occurred 4 hours 47 minutes later, it would have completely destroyed the Imperial Russian capital, St. Petersburg. A little later still, and the Tunguska meteorite would have wreaked chaos and destruction in densely populated Europe. Although scientists have advanced over 80 theories explaining the Tunguska event, none of them offers any conclusive evidence. Moreover, it is now impossible to verify them.

When I became an astronomer 30 years ago, I believed that the mystery of the Tunguska meteorite would never be solved. However, astronomers have since then obtained additional information about the origin of celestial bodies, and can offer more convincing explanations for the Tunguska blast.

I am going to tell an upcoming international conference in Moscow to mark the 100th anniversary of the Tunguska event that it was most likely caused by a comet fragment consisting of the Solar System's primary matter.

There are two kinds of comets in our Solar System. "Primary" comets consist of micron-sized inter-stellar dust and gas, whereas "secondary" comets feature meteorite substance. A disintegrating "secondary" comet forms the meteor showers that are frequently observed from the Earth. Some of their fragments do not burn up during reentry and can be recovered. On February 12, 1947, a large meteorite disintegrated spilled fragments over a 1.3-sq. km. area in the Sikhote-Alin range, some 440 km from Vladivostok in the Russian Far East. Subsequent expeditions recovered many iron fragments there.

The Astronomy Institute's experts and I believe that if the Tunguska meteorite were a "secondary" comet, then it would have contained several metric tons of meteor substance, and some of it could have been recovered.

It would be therefore logical to assume that the Tunguska meteorite was a huge gas-and-dust snowball, whose tiny fragments vaporized after hitting the terrestrial atmosphere. The remaining comet-nucleus also vaporized instantly, causing the loud and powerful air burst that was registered by many observatories all over the world.

When a "primary" comet blows up, surviving comet-nucleus particles, including tiny hard-to-melt dust, are dispersed in the Earth's atmosphere, subsequently becoming embedded in tree bark. Unfortunately, scientists in 1908 lacked modern methods for detecting space-bolide substances.

The Tunguska meteorite was a milestone in terrestrial history, highlighting the dangers posed by killer asteroids. The other two known large meteorites that fell in the sparsely populated Sikhote-Alin range on February 12, 1947 and on August 13, 1930 in the Brazilian Amazonas region (approximately latitude 5° S. and longitude 71.5° W.), near the Peruvian frontier, caused no substantial damage.

Such narrow escapes are either a coincidence, or God's Providence. At the same time, we know very little about meteorites falling into the world's oceans.

With the onset of the Space Age, humankind realized that the Earth was under constant threat from celestial bodies. Asteroid-and-comet studies have soared in popularity as people have become aware that these space objects have the capability to wipe out human civilization. Even now, numerous near-Earth satellites designed to detect ballistic-missile launches or unauthorized nuclear tests annually register 10-15 airbursts equivalent to a megaton of TNT. Most scientists believe that these explosions are the result of mini-comets burning up in the atmosphere.

Although we still lack the technology to deflect approaching asteroids and comets, we can watch the skies and evacuate the population of threatened areas in case of an impending strike.

Hollywood films notwithstanding, it would be unforgivably dangerous to use weapons to destroy an incoming asteroid. The resulting fragments could cause at least as much damage as the original object. Probably the best solution would be to land a small rocket on the asteroid's surface, exerting just enough force to gently change its trajectory. This would be far less spectacular, but could save thousands of lives, as well as humankind's material and spiritual heritage.

Doctor of Physics and Mathematics, Alexander Bagrov, is a leading research associate of the Astronomy Institute of the Russian Academy of Sciences.

The opinions expressed in this article are the author's and do not necessarily represent those of Trend .

“Covo-Pasteur”, “Barakat” vaccine to hit market soon: Rouhani
“Covo-Pasteur”, “Barakat” vaccine to hit market soon: Rouhani
Iran to import Coronavirus vaccine - President Rouhani
Iran to import Coronavirus vaccine - President Rouhani
Iran reveals COVID-19 data for May 8
Iran reveals COVID-19 data for May 8
Loading Bars
Israeli gymnast grabs gold in exercise with clubs at Rhythmic Gymnastics World Cup in Baku
Leadership of Azerbaijani MoD paid tribute to memory of compatriots, who died in Great Patriotic War (PHOTO)
Baku holds award ceremony of winners and prize-winners of Rhythmic Gymnastics World Cup at National Gymnastics Arena (PHOTO)
Azerbaijani team grabs bronze in exercise with 5 balls at Rhythmic Gymnastics World Cup in Baku
Italian gymnast grabs gold in exercise with ball at Rhythmic Gymnastics World Cup in Baku
Israeli gymnast grabs gold in exercise with hoop at Rhythmic Gymnastics World Cup in Baku
Final day of Rhythmic Gymnastics World Cup starts in Baku - Azerbaijani graces competing for medals (PHOTO)
Industrial enterprises to be put into operation in Iran’s Tehran Province
Azerbaijani Economy Ministry announces winner of tender on assessment of feasibility study
Turkey discloses number of ships received by Bandirma port from Jan. through March 2021
Azerbaijani president, first lady pay tribute to Azerbaijanis who made unparalleled contribution to victory over fascism (PHOTO/VİDEO)
EU and India agree to resume trade talks at virtual summit
Azerbaijan strongly condemns attempts to distort truth about WW2, justify fascism - MFA
First Vice-President Mehriban Aliyeva makes Instagram post on Victory Day over fascism (PHOTO)
India's COVID-19 tally surpasses 22 mln with over 400,000 new cases
China’s Long March-5B carrier rocket’s last stage enters atmosphere
Brazil sees 2,202 more COVID-19 deaths
Red Cross to hand over Georgia 100 thousand Sinopharm vaccine shots
Russia's 2M2021 import of Turkish cars grows in value
Turkey reports 18,052 new COVID-19 cases, 5,016,141 in total
“Covo-Pasteur”, “Barakat” vaccine to hit market soon: Rouhani
Daily COVID-19 case count at 2,350 in Kazakhstan
China reports 12 new COVID-19 cases vs seven a day earlier
Chile reports third consecutive day of over 6,000 daily COVID-19 cases
UN remembers the dead of WWII
2 people, including child, shot in NYC Times Square
Attack on Syrian government forces repelled in Idlib, at least ten militants killed
WHO records over 817,000 new daily cases of COVID-19 worldwide
Iraq decides to quarantine evacuees from India for 14 days as total cases hit 1,108,558
UK records another 2,047 coronavirus cases, 5 deaths
Azerbaijan marks Day of Victory in Great Patriotic War
Iranian trucks do not transport goods to Karabakh - Iranian embassy
NCDC: Georgia to receive extra half a million Sinopharm vaccine doses in June
Iran may extend cooperation on inspections with IAEA
Consumers must protect IoT devices - Fortinet
Azerbaijan’s Baku city has beautiful National Gymnastics Arena – Russian gymnast
Baku holds awarding ceremony of Rhythmic Gymnastics World Cup (PHOTO)
Azerbaijani team reaches finals in group exercises as part of Rhythmic Gymnastics World Cup (PHOTO)
WB plans to issue loan to finance another road project in Azerbaijan
Any attempt to glorify fascism is disgusting - Russian expert
Group team competitions underway in Baku as part of Rhythmic Gymnastics World Cup (PHOTO)
Azerbaijani ADA University sсreens film timed to Day of Victory in WWII (PHOTO)
Azerbaijan names finalists in exercise with clubs as part of gymnastics World Cup in Baku
Azerbaijani gymnast reaches finals in exercise with ribbon as part of World Cup in Baku
Iran providing much needed mechanization for farmers in Qazvin Province
Germany’s import of steel from Turkey up
Azerbaijani president allocates funds for construction of new school in Shusha
Funds allocated for construction, repairs of educational institutions in Baku
Uzbekistan interested in co-op with French pharmaceutical company
Funds allocated for creation of heat supply system in Azerbaijan’s Shusha
France’s import of steel from Turkey up
Iran's Energy Exchange announces products to be on sale on May 9
Azerbaijani Finance Ministry places medium-term bonds on auction
Cotton spinning factory of Turkmenistan’s Lebap region names production data
Chevron should remain cautious in further increasing oil & gas production
Azerbaijan to continue online lessons in 10th-11th grades, minister says
Foreign shipping lines expected to return to Iran
Austria increases import of steel from Turkey
Fars Province to be connected to north-east and south-east of Iran via railway line
1Q2021 value of operations via interbank national settlements system in Azerbaijan down
United Arab Bank turns around with Dh10.2 million net profit
Azerbaijan's MoD shares video about Shusha - cultural capital of Azerbaijan
New jobs created in Iran's Ardabil Province
Turkmenistan's Turkmengas opens tender for overhaul of gas turbine engines
Iran’s Bahar Azadi gold coin price falls
World Cup in Baku became one of my favorite competitions - Azerbaijani gymnast (PHOTO)
Khazar Consortium opens tender for purchase of controller
Value of Iran's import of Turkish steel in 4M2021 grows
Russia’s coronavirus reproduction rate remains below 1
Azerbaijan sets up new military units in liberated lands (PHOTO)
Kazakhstan increases exports to UAE
Best moments of second day of Rhythmic Gymnastics World Cup in Baku (PHOTO)
Kazakh gymnast shares impressions of Rhythmic Gymnastics World Cup taking place in Baku
Cult of personality of Garegin Nzhdeh in Armenia can be compared with that of Hitler in Nazi Germany – Russian analyst
Azerbaijan shares data on number of vaccinated citizens for May 8
EU sceptical on vaccine waiver, but ready to discuss proposal
Azerbaijan confirms 649 more COVID-19 cases, 1,720 recoveries
Iran declares details of exports from Ardabil Province
Uzbekistan projects volume of direct foreign investments for 2021
Exports via Iran's Sistan and Baluchestan Province up
Turkey's 4M2021 export of steel to Georgia surges in value
China boosts import of Azerbaijani products y-o-y
Azerbaijan's Central Bank unveils data on foreign exchange transactions over March 2021
Azerbaijani Ro-Pax type ferry reaches Kazakh port of Kuryk (PHOTO)
G-7 countries back Taiwan's observer status in World Health Assembly
Lack of minefield maps delays mine clearance - Trend TV
Uzbekistan’s 1Q2021 cars export revealed
Results of Azerbaijani gymnasts’ performance in exercises with clubs, ribbons as part of Rhythmic Gymnastics World Cup in Baku (PHOTO)
Turkish Energy Ministry prolongs oil, gas exploration licenses for several companies
Azerbaijani president displayed successful strategy on battlefield and in media - two tactics of Great Victory
Turkmenistan sees active dev't of cotton industry
Latvia reveals main economic indicators of bilateral cooperation with Georgia
Iran discloses number of restored mines in South Khorasan Province
Germany's confirmed coronavirus cases rise by 15,685
Azerbaijan's CBC radio starts broadcasting in Karabakh
Iran's Khorasan Razavi Province to increase trade with Turkmenistan
First Vice-President Mehriban Aliyeva made Instagram post on Shusha (VIDEO)
Iran to import Coronavirus vaccine - President Rouhani
Uzbekistan, Kazakhstan implementing road and railroad construction projects
Competitions in Baku always held at highest level - Slovenian gymnast
All news