Siberia, Russia, 30th of
June 1908. We are in a woodland area surrounding the Tunguska river, not far from modern day
Krasnoyarsk. Simply known as Tunguska. One of the most desolate areas of the most desolate
region of the Russian Empire. It’s a crisp, cloudless morning. All is
quiet, but the event is about to happen. In a few minutes the sky will open in two, torn
asunder by fire and a sound of thunder. A storm of time and space will descend from
the sky and strike at the Earth. Welcome to today’s Geographics. Today we
are going to explore Tunguska, an area whose name would be confined to the Atlases, if
it wasn’t for the mysterious event that lit the skies and shook the Earth for a radius
of 1000km. An event, and a mystery, that would take 105
years of research before we could finally write the words ‘The End’.
The Event 7:17 AM, 30th of June 1908, a mysterious explosion
occurred in the skies above the Tunguska river. 1000 km [600 miles] away from ground zero,
seismic vibrations were recorded, as intense as the 5th degree of the Richter scale.
At 500 km [300 miles] witnesses reported "deafening bangs" and a fiery cloud rising above the
horizon. At about 170 km [110 mi] from the impact,
just before the explosion, an object was spotted in the clear, daytime sky: as a brilliant,
sun-like fireball travelling at enormous speed, leaving a trail of thunderous noises.
60 km [40 mi] from ground zero, at the time of the explosion: people were thrown to the
ground by the shock waves, or even knocked unconscious. Windows shattered in a hail of
shards, while furniture, crockery and other objects fell to the ground.
We are now at 30 km [20 mi] from the site of the explosion, the closest inhabited area.
Few moments before the blast, a group of reindeer herders are asleep in their tents. And then
a sudden deflagration sends them flying through the air, knocking them unconscious.
An elderly herder is sent flying for 12 metres [40 ft] smashing into a tree, causing a compound
fracture of his arm. He will later die from his injuries. Hundreds of the herders' reindeer
are killed. Trees are set ablaze and fall to the ground, their tops pointing radially
away from ground zero, like giant arrows. Another herder reported:
"The ground shook and an incredibly prolonged roaring was heard. Everything round about
was shrouded in smoke and fog from burning, falling trees. Eventually the noise died away
and the wind dropped, but the forest went on burning. Many reindeer rushed away and
were lost." What happened?
Eye witnesses in Kirensk and nearby towns share the same recollection of a fireball
flashing across the sky: "A ball of fire...coming down obliquely. A
few minutes later [we heard] separate deafening crash like peals of thunder...followed by
eight loud bangs like gunshots." "A ball of fire appeared in the sky... As
it approached the ground, it took on a flattened shape..."
"A flying star with a fiery tail; its tail disappeared into the air."
After the object crossed the sky and it approached the horizon it was consistently described
as a pillar of fire. The fire ball appeared two or three times larger than the sun, but
not as bright; the trail was like a fiery-white stripe, its colour sometimes changing to red
and bluish-white. Some minutes after the explosion, distant
observers reported a vertical column of smoke on the horizon. One observer said
"Where the body disappeared behind the horizon, a pillar of dark smoke rose up."
It was unclear from reports whether the pillar was a mushroom-like cloud generating directly
from the explosion or smoke from the forest fires.
Days later, strange phenomena were observed in the sky of Russia and Europe, like glowing
clouds, colorful sunsets, and a weak luminescence in the night.
Unfortunately, the inaccessibility of the region and Russia's unstable political situation
at the time prevented any further scientific investigation.
It would take 19 years before mineralogist Leonard Kulik organised an expedition to investigate
what may have happened. Tunguska after the event: exploration and
research In 1921 Leonard Kulik, former soldier, revolutionary
and now professor of mineralogy, was charged with locating and examining meteorites that
had fallen within the Soviet Union. While preparing for this expedition, he came across
an account of an explosion in Tunguska reprinted from an old newspaper. During his first expedition
Kulik only managed to figure out the general location of the blast area, not actually visit
it. He continued to collect stories about the event, one tickled his curiosity in particular,
from ethnographer I. M. Suslov. He had collected the story of a family living
25 miles from the blast. The entire group was thrown down by the force of the blast
and several knocked unconscious. The wife reported that when they awoke they found
"...the forest blazing around them with many fallen trees"
Some of the children described "A terrible storm, so great it was difficult
to stand" Kulik organised a 2nd expedition in the spring
of 1927. The trip was not an easy one: the maps were inaccurate, the compasses seemed
to be ‘confused’, the terrain inhospitable. By end of March Kulik reached the town of
Vanavara located on the Tunguska River: the last outpost of civilization before the expedition
had to traverse the swampy forest, where Kulik was sure to locate the site of the event.
Kulik tried to interview the locals but found that many of them did not like to discuss
the event. The ethnic minority of the Tungus still had shamanic beliefs and were convinced
that the event was a visitation of Ogdy, the local god of thunder.
Ogdy had cursed the area by smashing trees and killing the animals. No man now approached
the site for fear of being cursed by the god. Kulik had to wait for the snow to melt in
April and continued on horseback, his party suffering from infections and malnutrition.
After swapping horses with reindeer they reached the Makirta river and saw the first evidence
of the Tunguska blast: the fallen, charred trees.
Kulik noticed that the trees had been burned from above. He was sure it was the work of
a sudden flash of intense heat, not a forest fire. As they approached the epicentre, the
local guides grew wary of Ogdy’s wrath and refused to continue. Kulik had to return to
Vanavara and hire new scouts. Kulik’s expedition returned to the dead
forest on the 20th of May. The direction of the fallen trees pointed towards the Ground
Zero of the blast, which Kulik finally located: it was an area known as the Southern Swamp.
With the mind of a mineralogist, Kulik has formulated a simple hypothesis: the blast
had been caused by a meteorite. But when he reached Ground Zero, what he found was not
what he expected: first of all, there wasn’t any crater! How could that be? Moreover: at
the epicentre of the blast Kulik saw a standing forest of trunks, straight and tall, but charred
and stripped of branches, like telephone poles. The mystery was deepened by the eerie landscape.
Kulik wrote: "The solid ground heaved outward from the
spot in giant waves, like waves in water." Realizing that nothing more could be done
on this trip, with only three or four days of food left, Kulik decided to leave. He returned
for two more expeditions, in 1929 and in 1938. but both proved inconclusive: how could there
not be a crater? Another scientist, E. L. Krinov, returned
in 1940, his theory was that the meteorite had exploded mid-air, hence the absence of
a crater. Was that possible? More importantly: why couldn’t anybody find any specimen of
meteoric rock? Unfortunately, the War put an end to his research, and Tunguska remained
a mystery for decades. The fact that the event was investigated so
late, the scarcity of information outside scientific circles, the secretive nature of
Soviet regimes: all these factors have contributed to the proliferation of theories as to the
exact nature of what really happened in Tunguska. Some theories are fascinatingly outlandish,
others less so, but they are probably right. Let’s start with:
Theory #1: AliEn-ola Gay
Engineer and sci-fi writer Aleksander Kasantsews and Soviet scientist, Alexei Zolotov argued
that a nuclear explosion of possible extraterrestrial origin caused the Tunguska blast. Either a
UFO crashed in Siberia due to a malfunction or an interplanetary weapon was detonated
there for unknown reasons. Kasantsews also claims that geomagnetic anomalies recorded
at the station of Irkutsk were similar to that of a nuclear blast.
T.R. LeMaire, a science writer, continues this thought, but suggests that the blast's
timing seems too fortuitous for an accident. Calculating the rotation of the Earth, he
claims that a five-hour delay would make the target of destruction St. Petersburg. Or a
small change of trajectory would have devastated populated areas of China or India.
LeMaire maintains that "the flaming object was being expertly navigated"
using Lake Baikal as a reference point and changing direction twice mid-flight.
His fascinating conclusion is that the alleged aliens may have been on a bombing mission
similar to Enola Gay’s. Also the weather conditions – a clear sky – were favourable.
But at the last moment, they opted for an act of clemency and dropped their weapon on
an inhabited area. If that is the case, I wonder: have they been court-martialled? And
are their overlords preparing a second expedition? [Fade to black, then to next title card:]
Theory #2: Tesla did an oopsie
Another theory puts the blame on a failed experiment by Nikola Tesla.
This is related to one of his projects: the Wardenclyffe Tower which stood 60 metres or
187 feet tall and was located on Long Island, New York.
The purpose of the tower was to facilitate world-wide wireless communication and to deliver
electrical energy over great distances, something Tesla had achieved on a smaller scale with
his Coil. The project was scrapped when financiers backed
down. But the theory goes that around the Tunguska event, explorer Robert Peary was
on an expedition to the North Pole. Tesla contacted him before the trip and asked him
to report back on anything unusual he encountered. So, could Tesla have fired a blast of energy
at the uninhabited North Pole and missed, hitting Tunguska instead?
This theory aligns with those who claim that Tesla’s Wardenclyffe Tower was an operational
superweapon: a death ray. Tesla claimed that he did design and test a similar device later
in his career, a beam projector called Teleforce. But let’s step away from science fiction
now. Theory #3:
Super Diminutive Black Hole In 1973 a paper was published in the journal
Nature, suggesting that a black hole collided into Earth, causing the explosion. The theory
was put forward by the Centre for Relativity Theory, University of Texas. A small black
hole descended upon Tunguska, created the crater-less impact, sped through the Earth
and then exited the Planet in the North Atlantic. To validate the theory, all it would take
is to investigate the bottom of the Ocean for the ‘exit wound’. Nobody has ever
financed that expedition, and the theory was discredited.
Along the lines of theoretical physics, another hypothesis suggests the Tunguska event could
have been the result of matter and antimatter colliding. When this happens, the particles
annihilate and emit intense bursts of energy. Also this theory remained unproven.
Theories #4 and #5: A Song of Ice and Fire
Following Kulik’s expedition, Russian researchers where puzzled by the lack of craters and alien
rock fragments at Ground Zero. They tried to explain this by positing that it was the
icy fragment of a comet, to cause the damage. Comets are largely made up of ice: it is possible
that a large block detached from a larger body and plummeted to Earth. The ice would
have evaporated violently as it entered Earth's atmosphere causing the blast.
An opposite theory emerged in the 1960s: fire from the Earth. Verne shots, named after author
Jules Verne, are speculative magma reactions that violently erupt from the underground.
A magmatic intrusion beneath Siberia may have formed a large bubble of trapped volcanic
gases. The covering rocks shattered and bursts of burning methane caused the series of explosions
described by witnesses. But geologists mapping the area found no traces
of shattered rocks or gas vents. This leaves us with:
Theory #6: The Obvious One
The obvious explanation was that a meteorite, made of rocky material, had exploded before
hitting the Earth’s surface, like Krinov had theorised. This explained the lack of
a crater, but what about the absence of fragments? In 2013 a team led by Victor Kvasnytsya of
the National Academy of Sciences of Ukraine team put a stop to all speculations. The researchers
analysed microscopic samples of rocks collected from the explosion site in 1978. The samples
were found to be of meteoric origin and were recovered from a layer of peat dating back
to 1908. So, the fragments were there, but nobody had
thought about looking for the very small ones! The fragments had traces of lonsdaleite, a
mineral known to form when a meteor, crashes into Earth.
Kvasnytsya stated "We believe that nothing paranormal happened
at Tunguska." Alright, but the alien bombing theory has
its merits "We believe that nothing paranormal happened
at Tunguska." OK, but Tesla? Modern science seems to believe
"We believe that nothing paranormal happened at Tunguska."
[Note to Simon and Shell – this is an idea for a small gag. When Simon tries to mention
again the ‘paranormal’ theories, the editing abruptly cuts his speech, with an immediate,
stark transition to the title card with Kvasnytsya’s quote. The quote could be read by Simon with
a much colder and ‘plainer’ tone than usual]
Fine, you win. Altogether now: "Nothing paranormal happened at Tunguska."
[Continuation of previous gag: Now the caption appears at the bottom of the screen, with
a ball bouncing on every word, Karaoke-style] Today the consensus is that the Tunguska event
was caused by a large meteor colliding with Earth's atmosphere.
First, the cosmic body entered our atmosphere at about 15km per second.
[9 miles per second] Our atmosphere is a great protective shield,
generally successful in breaking up rocks a few kilometres above the Earth's surface,
producing an occasional shower of smaller rocks that, by the time they hit the ground,
will be cold. These large cold fragments are the ones that normally dig a crater.
But in the case of Tunguska, the incoming meteor must have been extremely fragile, or
the explosion so intense, that it obliterated all its remnants 8-10km above the Earth.
This process explains the event's second stage. The atmosphere vaporised the object into tiny
pieces, while at the same time intense kinetic energy also transformed them into heat.
The sudden release of heat accounts for all phenomena observed by eyewitnesses and scientist:
the powerful blast, the extensive shock wave, the forest fires and the absence of a crater.
Now think about that: 15km per second. That’s 900 km per minute, 560 miles per minute. The
meteor could have flown the whole width of the US, coast to coast, in about 5 minutes.
It would have taken just a few extra seconds for the meteor to hit a less desolate area.
What could have happened, if humanity hadn’t been so lucky on that day?
60 Degrees Azimuth The explosion caused one victim, in my opinion
one too many, but it could have been a catastrophe of much larger magnitude.
The meteor was assumed to be 30 metres wide, its mass estimated to be at 42 Million Kg,
or 93 million pounds. Based on these parameters, you can calculate
the total energy released by the explosion via the formula in the caption below. You
read it, I am not going to even try. [Caption: E=1/2 (4.2 x 107 kg) (1.5 x 104
m/s)2 = 4.8 x 1015 joules] Assuming half of the energy is dispersed to
noise, attrition and fragmentation, the explosive energy remaining is equivalent to 500 kilotons
of TNT – that’s 60 times the explosive power of the bomb dropped on Hiroshima. Other
accounts claim 185 times, but let’s stick to the conservative estimate.
The projectile travelled in a southeast to northwest direction. A quick look at Google
Maps will show you that the land north west of Krasnoyarsk is still sparsely inhabited
today. If any Russian viewers would like to confirm or dispute, please use the comments.
Depending on the angle to which the object travelled, though, you could draw a straight
line from Krasnoyarsk to St Petersburg. The then capital of the Russian Empire is located
at about 3600 km or 2200 miles from the site of the impact. But what if the object had
travelled at a slightly different angle, than the 60 degree azimuth evaluated by researcher
Fesenkov? This is the angle between the trajectory of
the flying object and the Earth surface at the point of impact. Astrophysicists please
correct me. At a different angle, and with its speed,
it would have taken only four additional minutes for the object to reach St Petersburg.
A city which according to a 1905 census counted 1.6 million inhabitants. I will leave to your
imagination the effects of 60 Hiroshima bombs hitting an urban area with such a population.
The blow on the Russian Empire would be devastating, the enormous death toll would leave an enduring
scar on the country, victim to the largest loss of life in one single event in the history
of humanity. What of the effects on the History of Russia?
Around May and June of 1908 Tsar Nicholas II and the Tsarina Alexandra were in the Baltic,
hosting a visit from the British King Edward VII. We don’t know their location on the
30th of June, but let’s assume they were at sea and survived.
The rest of the political leadership may not have the same luck: the destruction in St
Petersburg would obliterate the Fourth Duma. This was the parliament instituted after the
1905 revolution and its fourth term was a conservative assembly with little representation
of opposition and minority groups. The ‘St Petersburg event’ would radically
modify the make-up of Russian society. Nicholas’ leadership was already on shaky ground after
1905 and the tragedy of June 1908 would decapitate the political class supportive of his rule.
This may result in an anticipated version of the 1917 revolution. Veterans from the
1905 uprising may take the opportunity to establish a separate government and assembly
in Moscow, ousting the Tsar. A Russian civil war may ensue like in our
timeline, maybe without a foreign intervention. France and the UK were tied to the Russian
Government, but these were defensive alliances against Germany, so maybe they would not intervene
to support the Tsar. Plus, unlike our timeline, the French and British armies were not fully
mobilized in 1908. Could have this resulted in a consolidated Soviet Union several years
in advance? Alternatively: what if the ‘St Petersburg
event’ spurred a unitarian movement in Russia instead? What if the other European countries
rallied together to provide humanitarian aid to the stricken Empire? What if the British
and Germans set aside their naval rivalry pre-WWI to better assist Russia?
I realise we went from science fiction to science, then back to science fiction, so
I will stop here. If we have any ‘alt historians’ in the audience, please write your scenarios
in the comments. When can we expect the next Tunguska?
When can we expect the next Tunguska event? Well, one already happened on the 15th of
February 2013, when a smaller meteor burst in the atmosphere near Chelyabinsk, Russia
again. This event created an opportunity for researchers
to apply modern computer modeling techniques to explain what happened. Based on the current
knowledge of the asteroid population, an object like the Chelyabinsk meteor can impact the
Earth every 10 to 100 years on average. That’s quite a frequency, but the blast of this meteor
was less violent than Tunguska’s, resulting in an estimated 1 million broken windows and
several injuries, none fatal. But what about the larger rocks, like the
one at Tunguska? By combining clues from the magnitude of that
event with the most recent asteroid population estimates, NASA researchers have concluded
that the average interval between such impacts to be on the order of millennia, rather than
centuries. Still, NASA’s advice is to remain aware
and prepared for such a hazard. Asteroids have hit the Earth and more asteroids will
hit again. The systems NASA is developing will ensure we can better prepare for dangerous
impacts. Here are some words of reassurance from Lorien
Wheeler, a researcher working on NASA’s Asteroid Threat Assessment Project:
"Because there are so few observed cases, a lot of uncertainty remains about how large
asteroids break up in the atmosphere and how much damage they could cause on the ground.
However, recent advancements in computational models, along with analyses of the Chelyabinsk
and other meteor events, are helping to improve our understanding of these factors so that
we can better evaluate potential asteroid threats in the future."
Tunguska is now considered an astronomical ‘cold case’, but forensic research on
the event is inspiring modern-day investigators to mitigate future threats.
Thinking about a potential forthcoming impact, I would venture a piece of advice to NASA,
or the ESA, or whoever will save the World: do not take inspiration from Hollywood! Instead
of taking some oil drilling experts and teaching them to be astronauts … isn’t it easier,
quicker and cheaper to take astronauts and teach them how to drill and plant explosives
instead? That was it from me for today, please leave
your comments, corrections and alternative scenarios in the comments … and as usual,
thank you for watching
