by Mark W. Brazo and
Steven A. Austin
Research Associate in Geology
Institute for Creation Research Website
Major catastrophic occurrences on Earth are infrequent.
Explanation of events even in recent historical times can prove to
be most difficult.
A catastrophe may be defined as a natural event of large magnitude
(energy), short duration, wide extent and low frequency. The
Tunguska (pronounced: toon-goos’-ka) explosion of 1908 fulfills all
five parts of the above definition and can be considered the epitome
of a cosmic impact catastrophe. An understanding of this unique
event and its origin could provide insight into large ancient
asteroidal or cometary collisions with the
Earth (e.g., Sudbury and Popigay impact structures) and possible global catastrophic effects
(e.g., from flooding, tectonism, volcanism, glaciation and air blast
waves). Catastrophism, a doctrine spurned by uniformitarian
scientists in the twentieth century, is now being confirmed by
events which have occurred in this century.
The scientific interest stimulated by the Tunguska explosion of 1908
has produced enormous speculation and controversy as to its origin.
The theories offered by those who have studied the event range from
the realm of science (a meteorite, comet, or nuclear explosion) to
the realm of science fiction (a black hole, anti-matter rock, or an
Each theory has protagonists promoting and defending their point of
view in light of the evidence, yet, because the scientific community
did not view the actual event, but only observed the devastating
results (it was 19 years after the impact before the first scientist
arrived on the scene), each theory contains some speculation.
Before delving into the specifics of each theory, it is important to
review the actual facts of the event.
Description of the Event
The Tunguska explosion occurred on the morning of June 30, 1908 at
7:17 A.M. local time (0h 17m 11s U.T.) in the area of the Stony
Tunguska River with the coordinates of the epicenter being 60º55’ N,
101º57’ E (Kridec 1966). This location is in the central Siberian
area of Russia, approximately 1000 km north of the town of Irkutsk
and Lake Baikal (Figure 1 below).
FIGURE 1. Area
map of the 1908 Tunguska explosion event.
After Sullivan 1979.
The first report of the explosion was in
the Irkutsk paper dated July 2, 1908, published two days after the
...the peasants saw a body shining
very brightly (too bright for the naked eye) with a bluish-white
light.... The body was in the form of ’a pipe’, i.e.
cylindrical. The sky was cloudless, except that low down on the
horizon, in the direction in which this glowing body was
observed, a small dark cloud was noticed. It was hot and dry and
when the shining body approached the ground (which was covered
with forest at this point) it seemed to be pulverized, and in
its place a loud crash, not like thunder, but as if from the
fall of large stones or from gunfire was heard. All the
buildings shook and at the same time a forked tongue of flames
broke through the cloud.
All the inhabitants of the village ran
out into the street in panic. The old women wept, everyone thought
that the end of the world was approaching
S.B. Semedec, an eyewitness in the village of
Vadecara about 60 km
south of the explosion site, provided excellent information:
...I was sitting in the porch of the
house at the trading station of Vadecara at breakfast
time... when suddenly in the north... the sky was split in two and
high above the forest the whole northern part of the sky
appeared to be covered with fire. At that moment I felt great
heat as if my shirt had caught fire; this heat came from the
north side. I wanted to pull off my shirt and throw it away, but
at that moment there was a bang in the sky, and a mighty crash
was heard. I was thrown to the ground about three sajenes [about
7 meters] away from the porch and for a moment I lost
consciousness.... The crash was followed by noise like stones
falling from the sky, or guns firing. The earth trembled, and
when I lay on the ground I covered my head because I was afraid
that stones might hit it
Through comparison of old seismograms of
the Tunguska event and seismograms of the decaya
Zemlya and Lop-Nor
nuclear-weapon tests, Ben-Menahem (1975) determined that the
Tunguska projectile had "the effects of an Extraterrestrial Nuclear
Missile of yield 12.5 ± 2.5 megatons." This is approximately 3 orders
of magnitude greater than the Hiroshima A-bomb and about one-fifth
the energy of the largest hydrogen bomb explosion (McWhirter and
McWhirter 1974). The height at which the explosion occurred was
estimated to be approximately 7.5 km, with a total energy release of
approximately 3×1023 ergs, 5×1018 ergs of which was changed into
seismic energy (Ben-Menahem 1975). More energy went into the air
blast than the earthquake. F.J.W. Whipple (1930) estimated the
energy of the air blast wave to be 3.2×1020 ergs. The seismic
activity measured on the Richter scale was 5.0; and the air
compression wave went twice around the world, according to
recordings at meteorological stations.
The projectile traveled in a southeast to northwest direction with a
60º azimuth, according to Fesenkov (1966) who made use of eyewitness
accounts and an inspection of the radial symmetry of the trees at
the explosion site. This direction was probably immediately prior to
the explosion; however, there are conflicting reports as to the
actual line of flight (discussed later when dealing with the causal
theories of the Tunguska explosion).
The temperature at the center of the fireball was estimated by one
source to be up to 30 million degrees Fahrenheit (LeMaire 1980).
Some storage huts in the nearby vicinity of the focus were found
devastated by fire and the silverware and tin utensils within were
deformed by intense heat.
"Preceding the front of the shock wave
there arises a heated zone whose radiating surface area is far
larger than that of the shock wave itself"
This is substantiated by Semedec who first felt the
heat wave, then was thrown to the ground by the air shock wave.
The inhabitants of Central Siberia saw the fall and explosion of the
meteorite over an area with a radius of 600-1000 km. Eighty million
trees in the taiga (coniferous forest) were uprooted and blown down
for a radius of 30-40 km (F.J.W. Whipple 1934). Some trees on the
leeward side of hills were somewhat protected, yet still had their
branches broken off and bark stripped to leave them standing naked,
resembling telegraph poles.
After the impact, forest fires broke out and ravaged an area of
10-15 km in radius (Astapowitsch 1934). Kridec (1960) describes
these forest fires as being unnatural. The trunks of trees and their
branches were not burned through but were only scorched on the
surface. Apparently a searing heat wave caused the scorching, yet a
conventional forest fire was not present. Some trees were entirely
scorched in standing position, but were bent away from the
epicenter. In normal fires in the Vadecara area, trees remained
vertical with fire damage occurring at the lower sections while the
tree tops remained untouched. It is also interesting to note that
some trees which had been stripped of bark showed no signs of
scorching (Kridec 1963).
The nights following the Tunguska meteorite were anomalous.
Abnormally bright nighttime illumination was reported throughout
Europe and Western Russia to the extent that people could read news
print at midnight without artificial lighting (Kridec 1966). The
cause of the anomalous illumination of the night sky is discussed
The Russian government made no immediate attempt to investigate the
event, due to its internal political upheavals at the time of the
explosion, and because the incident occurred in such a desolate area
without harming anyone. In 1921, the country’s fledgling Academy of
L.A. Kulik, a science worker at their
Museum, to head a team of investigators who would travel through
Siberia with the purpose of gaining information concerning
meteorites from the local populace.
Kulik collected newspaper articles and questioned eyewitnesses in
his attempt to pinpoint the time and location of the Tunguska fall.
However, due to the lateness of the year (late autumn), the
expedition did not attempt to maneuver through the taiga to
investigate the impact site. In his four succeeding expeditions
covering 1927-1939, Kulik obtained many sensational eyewitness
accounts concerning the Tunguska meteorite.
In a local newspaper, the reporter described the bolide (a bright,
detonating fireball) itself as a "body of fiery appearance" and a
tail (probably a dust trail) as a "radiance." Other articles
described "a fiery body like a beam shot from south to north west"
with "a tongue of fire" appearing in place of the fiery
One witness to the event, a train engineer, said he felt "a kind of
strong vibration of the air," then heard a "roar" which he believed
to be "an earthquake or some other natural phenomenon," and which
frightened him to the extent that he stopped the train thinking that
it had gone off the rails (Kridec 1966). In fact, when he arrived at
the station, he asked for an inspection to locate the problem on the
Another eyewitness reported that a thousand reindeer owned by the
Evenki people were killed and many carcasses burned by the ensuing
forest fire. It was one of the Evenki people, Okhchen, who
eventually led Kulik to the impact site (Kridec 1966).
Potapovich, who served as a guide for Kulik, told Kulik that,
"his brother’s hut was flattened to
the ground, its roof was carried away by wind [apparently some
sort of tent structure], and most of his reindeer fled in
fright. The noise deafened his brother and the shock caused him
to suffer a long illness"
Potapovich’s brother lived on the
River located just outside the limit of the tree damage
(Figure 2 below).
FIGURE 2. Map
depicting fallen tree pattern (arrows represent direction) from
explosion of 1908.
This is a closeup of
the impact site of Figure 1.
After Sullivan 1979
and Kridec 1966.
In the trading station at Vadecara,
Kosolapov reported to Semedec (previously mentioned),
"a fierce heat
scorched my ears. I held them, thinking the roof was on fire...."
Windows broke and the oven door on Kosolapov’s stove flew off and
landed on the bed across the room (Kridec 1966).
A farmer in the Kezhma area (about 200 km south of the impact site)
related the following:
At that time I was ploughing my land
at Narodima (6 km to the west of Kezhma). When I sat down to
have my breakfast beside my plough, I heard sudden bangs, as if
from gun-fire. My horse fell on its knees. From the north side
above the forest a flame shot up. I thought the enemy was
firing, since at that time there was talk of war. Then I saw
that the fir forest had been bent over by the wind and I thought
of a hurricane. I seized hold of my plough with both hands, so
that it would not be carried off. The wind was so strong that it
carried off some of the soil from the surface of the ground, and
then the hurricane drove a wall of water up the Angara [a
perhaps]. I saw it all quite clearly, because my land was on a
After having obtained interesting and
tantalizing eyewitness and newspaper accounts during his 1921
expedition, Kulik was anxious to reach the Stony Tunguska River
region to locate the impact site of what he ascertained to be a
meteorite. In 1927 Kulik was able to return to search for the
Tunguska meteorite. After spending some time in Vadecara, Kulik made
arrangements for Evenki hunters to guide his party to the impact
site. Reaching the explosion site was an extremely arduous task.
The spectacle that confronted Kulik as he stood on a ridge
overlooking the devastated area was overwhelming. He saw an area
where trees up to three feet in diameter had snapped like
toothpicks, were uprooted and strewn across the landscape. Upon
closer examination, he located holes which he erroneously concluded
were meteorite holes; however, he did not have the means at this
time to excavate them.
During Kulik’s three succeeding expeditions to determine the cause
of the Tunguska event, his meteorite theory received no
substantiating evidence. Despite tremendous hardships caused by the
searing heat of summer, the coldness of winter and insufficient
funds for supplies and equipment, Kulik and his party persevered to
obtain evidence relating to the Tunguska explosion. Throughout his
investigations and those of others covering a total of fifty years,
there was no evidence of impacting iron, no impact craters, no
meteorite remnant and no strewn field of particles. The only
evidence left by the Tunguska bolide was toppled and burned trees.
The holes that Kulik thought to be from meteorites proved to be
The Comet Theory
Due to a lack of evidence for the meteorite theory proposed by
other theories were proposed to explain the Tunguska event. Various
authors (Cowan, Alturi and Libby 1965; Kridec 1960, 1966;
1976) have designated F.J.W. Whipple (1930-1934) as the initiator of
the cometary hypothesis. Whipple proposed,
"that the meteor was essentially a
small comet and that the tail of the comet was caught by the
(F.J.W. Whipple 1934).
However, in the same article only two
paragraphs later, he stated: "I do not feel much confidence in this
A model of a comet nucleus is offered by F.L. Whipple (1950). This
model consists of a large dirty snowball composed of dust and rock
interspersed with water, methane and ammonia ices. Kridec (1963) and
Hughes (1976) utilize this model to support their belief that the
Tunguska projectile was a small comet. Yet, interestingly enough,
F.L. Whipple (1975) questions such a possibility:
It appears unlikely, therefore, that
the Tunguska explosion was produced by a bona fide active comet
a hundred or so meters in dimension.... more likely, however,
the Tunguska object was an inactive, low-density, friable
body.... There is no reason to suspect that it was interstellar.
It is an understatement to suggest that
the origin of the Tunguska explosion is controversial.
There are various elements of the cometary hypothesis that explain
the eyewitness accounts and the associated physical data. Probably
the most important concept supporting the comet hypothesis is the
nature of flight of the Tunguska fireball. Fesenkov (1962) claims,
"According to all evidence, this meteorite moved around the Sun in a
retrograde direction, which is impossible for typical
Fesenkov notes that meteorites rarely hit the earth
in the morning, because the morning side faces forward in the
planet’s orbit. Usually the meteorite overtakes the earth from
behind, on the evening side. However, comets have a wide range of
orbits and velocities and could collide with the earth on the
morning side, hitting head on at a velocity of approximately 60
km/sec (130,000 mph or Mach Number 180). Fesenkov (1966)
demonstrates that the direction and angle of the attack toward the
earth was from behind the sun; thus, the glare of the sun prevented
In addition to the evidence of the bolide’s retrograde orbit was the
brilliant night sky observed in Europe and Western Russia. Fesenkov
(1966) points out that there was no anomalous glow on June 30, 1908,
but that there was such a glow on July 1, 1908. There was no unusual
illumination reported in the U.S., the southern hemisphere or in
countries east of the explosion site.
"The most probable explanation
for the anomalously bright nights associated with the Tunguska
meteorite fall would be that the meteorite was actually a little
comet with a dust tail pointing away from the sun"
"These properties of the [dust] distribution can be explained if the
cloud of cosmic particles was associated directly with the nucleus
of the Tunguska comet, and pointed in a direction away from the sun"
This is a plausible explanation in regard to the
brilliant nights observed in Europe. No other theory offered
adequately explains this anomaly.
More evidence supporting a comet came to light in 1962 when
technicians discovered microscopic pellets of magnetite and silicate
globules, thought to be extraterrestrial, in soil samples from the
Tunguska explosion site. A double spherule consisting of a
pellet inside a larger silicate shell is unique to this event and
thought to be the result of,
"rapid condensation of incandescent gas
The final piece of evidence for the Tunguska comet explains physical
observations satisfactorily. According to Whipple’s model described
above, the comet probably exploded prior to impact with evaporation
of the components thereby leaving no remnant. By comparing the
records of air waves from various sources, Ben-Menahem (1975)
deduced that the height above ground where the explosion occurred
was 7.5 km. There appear to have been three radiant centers made by
fallen trees, according to Fesenkov (1966), which would indicate
multiple explosions. F.J.W. Whipple (1930) noted that the air wave
recorded on the microbarographs appears to indicate two types of
waves; one generated by penetration of the object into the
atmosphere, and the other generated by the explosion or explosions.
The Nuclear Theory
The similarity between the Hiroshima A-bomb devastation and
the mysterious Tunguska effects gave rise to the notion that the
1908 event was caused by a man-made nuclear bomb. The fictional
writings of the Soviet author Alexander Kazantsev in 1946 were the
first to pick up the idea which scientists later considered. A
prominent Soviet scientist, Alexei Zolotov, after a 17-year
investigation, expanded the nuclear explosion theory by supposing it
was caused by the visit of an alien spacecraft (TASS
mid-October 1976). According to Zolotov, a spaceship controlled by
"beings from other worlds" may have caused the 1908 explosion. He
imagined a nuclear-propelled craft that exploded accidentally due to
a malfunction. Zolotov also admits to problems with the theory,
realizing that safety devices would probably prevent such a mishap,
and observing that the actual area of destruction was "an amazing
demonstration of pinpoint accuracy and humanitarianism."
T.R. LeMaire, a science writer, continues this thought, by
"The Tunguska blast’s timing seems too fortuitous for an
He claims that a five-hour delay would
make the target of destruction St. Petersburg, adding that a tiny
change of course in space would have devastated populated areas of
China or India.
Can we assume that the ’pilot’ chose a cloudless day with excellent
visibility from aloft to assure a safe drop? American Military
strategy called for identical weather conditions; for a perfect
strike on Hiroshima’s industrial heart, the Enola Gay’s bombardier
was forbidden to release through a cloud cover: he had to see the
target below. To maximize blast destruction, minimize radiation
perils: the bomb was set to explode at a high altitude rather than
against the ground. Similarly, the Siberian missile detonated high
in the air, reducing or even eliminating fallout hazard (LeMaire
LeMaire maintains the "accident-explanation is untenable" because
"the flaming object was being expertly navigated" using
as a reference point. Indeed, Lake Baikal is an ideal aerial
navigation reference point being 400 miles long and about 35 miles
wide. LeMaire’s description of the course of the Tunguska object
lends credence to the thought of expert navigation:
The body approached from the south,
but when about 140 miles from the explosion point, while over
Kezhma, it abruptly changed course to the east. Two hundred and
fifty miles later, while above Preobrazhenka, it
heading toward the west. It exploded above the taiga at 60º55’
N, 101º57’ E
Scientists who have reviewed eyewitness
reports are not convinced of any course changes as the brilliant
object traversed the sky. Neither are scientists convinced of
nuclear temperature. Brown and Hughes (1977) state that a
temperature of two million degrees Celsius (the supposed temperature
obtained if all the kinetic energy of the comet, 3×1023 ergs, was
changed into heating the component parts) is "substantially subnuclear." Furthermore,
"it is entirely fallacious to suppose that
the sub-nuclear temperatures cannot produce nuclear effects...."
They suggest that a thermo-chemical explosion could produce the
effects of a nuclear bomb.
The Anti-matter Hypothesis
The anti-matter hypothesis is offered by Cowan, Alturi and
(1965) and supported by Gentry (1966). This theory proposes that an
anti-rock composed of anti-matter was annihilated in the atmosphere
above the Tunguska explosion site and caused the observed damage.
Cowan et al. postulated that such an explosion would cause an
increase in atmospheric radiocarbon. Upon analysis of C-14 content
in a 300-year-old Douglas fir from Arizona, they believe that they
obtained increased radiocarbon for the time of the event. However,
the data presented in their paper appear to lack statistical
significance for support of their conclusions. Furthermore, careful
C-14 measurements of a tree nearer the blast fail to show an
increase in 1909 (Lerman et al. 1967).
The Black-Hole Hypothesis
The last theory as to the cause of the Tunguska event is proffered
by Jackson and Ryan (1973). They suggest that a black hole with a
mass of 1022 to 1023 g would have the necessary energy (1023 ergs)
to have caused the Tunguska destruction. Jackson and
that the black hole would cause the destruction as it pierced
through the earth with the ease of cutting soft butter, exiting the
earth through the Atlantic Ocean.
Beasley and Tinsley (1974) refute the black-hole theory because the
microbarographs that recorded the air waves of the explosion did not
record air waves of an exit point in the Atlantic Ocean. This is
vital to the black-hole theory because the exit of the black hole
from the earth would be expected to exhibit devastating effects
similar to those at its entrance.
The black-hole concept also does not explain the magnetite and
silicate globules found in the explosion region, nor does it account
for the anomalously bright night sky observed over Europe. Beasley
and Tinsley (1974) conclude,
"All the evidence favors the idea
that the impact which caused the Tunguska catastrophe involved a
body with characteristics like a cometary nucleus rather than a
The Tunguska explosion is indeed unique and mysterious. Of the
possible causes it appears that the present consensus favors the
comet hypothesis. However, suggesting a consensus is quite tenuous.
Though the other theories have plausibility, they have difficulty
explaining the observed event and the resulting physical evidence.
Making use of the cometary hypothesis allows for the following
Above central Siberia on June 30, 1908, at approximately 7:17 AM
local time, a small comet entered the atmosphere from behind the sun
and moved in a southeast to northwest direction. The comet was
composed of about 30,000 tons of water, methane, and ammonia ice
with traces of silicates and iron oxides. Penetrating the atmosphere
at approximately 60 km/sec (130,000 mph), the object created an
intense shock wave which wrapped tightly around its nose. As it
descended that sunny morning, its nucleus exploded (possibly 3
times) approximately 8 km above the Earth’s surface.
A huge black cloud immediately appeared
following the explosion which released 1023 ergs of energy. A heat
wave with a temperature of approximately 16.6 million degrees
Celsius at the focus was generated that had a tree-scorching effect
for a radius of 15 km. The heat wave was followed by air shock waves
which disfigured or toppled 80 million trees occupying approximately
8000 km2 of Siberian taiga (a radius of 30 km), and initiated a
seismic wave of Richter magnitude 5, but, to our astonishment, left
no crater. The dust from the tail of the comet moved away from the
sun and provided anomalously bright night sky in Europe and parts of
Western Russia. No trace of the comet itself was found except for
tiny magnetite and silicate globules. The principal consequences
were fear and awe among the inhabitants of the region, and the
physical damage from the explosion. Fortunately, no human life was
lost, though more than a thousand reindeer were destroyed.
Speculation will continue as to the origin of this catastrophe, yet
no certain conclusions can be attained unless man has the dubious
opportunity to observe and monitor such an event in the future. The
Tunguska explosion directs our attention to catastrophic forces
which have helped form the earth, and causes us to ask questions
about the nature of much larger cosmic events. What were the global
effects of enormous impact events which formed the 1-km-diameter
Meteor Crater in Arizona (left image), the 100-km-diameter
Popigay crater of
Siberia, and the 140-km-diameter Sudbury impact structure of
Ontario? What changes in the earth’s crust, atmosphere, ocean and
life were caused by the release of a million times more energy than
the Tunguska explosion? The Tunguska event provides a faint glimpse.
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