by Lee Krystek
The first officer turned to his commander with a stoic
expression. "Emergency landing procedures are in place.
Descending on a six-point two-degree path through the
atmosphere, Captain," he announced, "Optimum angle to avoid
burning up, or skipping back out into space."
"Very well," the Captain acknowledged with a nod. "What does the
landing site look like?"
"Isolated from most of the native population and near a major
body of fresh water we can use while we make our repairs.
Touchdown should be in-"
Somewhere on the bridge a siren went off. The ship began to
"Captain," a young ensign assigned to the engineering station
cried, "Core integrity has dropped 30 percent in the last 15
seconds. We’re losing control!"
"Confirmed," added the first officer checking his computer. He
turned to the captain. "Temporary repairs are not holding. Core
collapse will occur within the next five minutes. All backup
systems have failed."
The two officers’ eyes met. They both knew there was nothing
that could be done.
"Put the native population map on screen."
front of them appeared the dark outline of a continent with
white dots speckled across it. Most of them appeared along the
edges. Toward one side of the ship’s course lay a particularly
The first officer pointed. "Captain, there-"
"I see it. Helm, change course to
The young ensign hesitated. "Captain, that will accelerate the
"Make that turn," the Captain commanded, "NOW!"
The ship lurched as it violently changed its path.
"Core integrity down to 10 percent, Captain."
"Altitude 5 kilometers."
"WARNING!" a mechanical voice screamed, "Core failure is
In an instant the ship’s nuclear engines overloaded and exploded
with the force of 30 million tons of TNT. The vessel and crew
were vaporized. The atomic explosion scorched the planet below
and a column of fire split the sky. A wall of superheated air
pounded the surface crushing 1,200 square miles of forest. Above
the continent a mushroom cloud formed...
The above dramatization is one of the
wilder theories proposed to explain the great Siberian explosion
that occurred over central Asia on June 30, 1908. On that day
something fell out of the sky. Something that produced the largest
explosion in human memory. The largest explosion, that is, until the
H-bomb was invented.
The object, whatever it was, appeared above Western China, heading
due north, just after seven in the morning. It plunged through the
atmosphere glowing with the heat of 5,000 degrees. In central Russia
it moved overhead with a deafening supersonic roar that terrified
the inhabitants. Before the object raced a ballistic wave that
leveled trees and knocked over houses.
Then at 7:17 AM, near the Stony Tunguska River, a cataclysmic
explosion occurred. It was so powerful that the seismograph at
Irkutsk, some 550 miles away, registered what looked like an
earthquake. Even in Washington D.C., on the other side of the world,
the shock was recorded by sensitive seismic devices.
Forty miles from the blast center at a town called Vanavara, people
were thrown into the air by a shock wave that shattered windows and
collapsed ceilings. Herdsmen working closer to the site were
deafened by a series of thunderclaps that could be heard for 500
miles. Near the town of Kansk, a stop on the Trans-Siberian Railway,
a train screamed to a halt when the engineer feared it would be
thrown from its tracks by the violent shaking. Passengers were
jolted from their seats by the movement. Kansk was 375 miles from
the blast center.
As the shocks settled down the whole region around the Tunguska was
showered with "black rain": condensation mixed with dirt and debris
sucked into the swirling vortex of the explosion and thrown out
again. Amazingly the blast point was so isolated that there was no
record of any human being dying at Tunguska despite an explosion
that would have dwarfed the bombs dropped at Hiroshima
and Nagasaki during WWII. So isolated that no scientist bothered to
investigate the rumors of the event for thirteen years.
in 1921 a Russian scientist named Leonid Kulik was charged with the
task of locating and examining meteorites that had fallen within the
Soviet Union (Meteorites are rocks in space, sometimes
referred to as
asteroids, that fall to Earth. If they burn up as they hit the
atmosphere they are called meteors). While preparing for the
expedition he came across an account of the Tunguska
reprinted from an old newspaper. It took him six years to finally
find the site of the blast.
On April 13, 1927, Kulik stood on the edge of the Makirta River and
looked out across the land at the immense devastation. "The results
of even a cursory examination exceeded all the tales of the
eyewitnesses and my wildest expectations," he wrote.
Kulik discovered an oval more than 40 miles wide where the forest
had been flattened (above-left). Trees were uprooted, burned and
laid with their tops pointing out from the heart of the affected
region. At the center Kulik expected to find a large crater where
the meteorite had hit along with fragments of the meteorite itself.
Instead of finding a crater in the center, Kulik found a very
strange forest. Trees here were not pushed over and uprooted.
Instead they stood straight up like telephone poles and were
stripped of their branches. A careful search of the area also
yielded no remnant of any meteorite.
Kulik continued to look for the meteorite, unsuccessfully, for the
rest of his life, but other scientists began to think that perhaps
the object was something else. In the early 1930s two astronomers,
F.J.W. Whipple and I.S. Astapovich independently came to the
conclusion that the object had been a gaseous comet (far below)
that had left no trace of itself after impact. Still, if a comet hit
the ground, where was the crater? (see
the 1940’s a Russian scientist named E.L. Krinov, who had traveled
to the site on one of Kulik’s trips, suggested there was no crater
because the object must have exploded before hitting the ground.
Unfortunately further work on Krinov’s theory had to be put off. The
Soviet Union became engaged in defending itself from Germany during
WWII and there was little time or money available for scientific
research not connected with the war effort.
The war brought with it a new, terrible weapon. The weapon’s use,
though, brought new insight on the Tunguska explosion. Aleksander
Kazansev was one of the first Russian scientists to evaluate the
atomic bomb explosion at Hiroshima, Japan. He was also intrigued by
the mystery of the Tunguska blast and quickly found connections
between the two. The strange forest of trees, stripped of branches,
but still standing, was found at Hiroshima too. The American atomic
bomb had exploded at high altitude and the downward rushing shock
wave had left the trees directly beneath standing while flattening
trees, and houses, further out in a radiating pattern. The mushroom
shaped cloud and the black rain that followed the Hiroshima blast
also conformed to reports from Tunguska.
Kazantsev was the first to suggest that the event was the caused by
the explosion of an atomic powered spaceship. While most scientists
laughed at this explanation, some took seriously his suggestion the
blast was atomic in nature, and they began to notice other
similarities. This included apparent effects from radiation. Both
the reindeer population at Tunguska and the human population at
Hiroshima developed similar skin diseases. There was also evidence
of accelerated plant growth at both locations.
Some scientists suggested that if the blast was atomic in nature it
might have been explained by some natural phenomenon, rather than a
spaceship. Two possible candidates are an anti-matter meteorite or a
Anti-matter is material with a reversed charge at the sub-atomic
level. As far as we know it is extremely rare in the universe, but
it has been produced on Earth in laboratory experiments. When
anti-matter meets up with normal matter they annihilate each other
in a burst of energy. A small chunk of anti-matter could make an
enormous explosion. If the Tunguska meteor was made of anti-matter
it would have exploded violently when it came into contact with the
thick, lower atmosphere. The effects of the explosion would have
looked very much like that of an atomic bomb.
One objection to the "anti-rock" theory is that an
explosion should have set off a chain of events leading to a
significant rise in the amount of radioactive carbon-14 in the air.
Scientists examined tree rings laid down in 1908 and found a rise in
carbon-14, but not enough to support the idea of an annihilation
large enough to explain the explosion.
"Black holes" are usually the final result of the collapse of a
large star at the end of its life. Some cosmic theories suggest,
though, that "mini-black holes" might have been created at the
beginning of the universe and drift aimlessly through galactic void.
The density and resulting gravitational pull of such an object is so
high that not even light can escape from it. A mini-black hole
passing through the Earth certainly would have produced many of the
effects seen by witnesses of the Tunguska event. What it would
probably not have produced is the visible sighting as seen as the
object entered the atmosphere. A black hole should have also
produced a crater. For these reasons, argue some scientists, a
mini-black hole is not a serious contender to explain what happened.
In the 1960’s several Soviet scientists tried to show that the
object had changed course during its descent. They based their
theory on eye-witness accounts and ground damage from the ballistic
shock wave that proceeded the object as it traveled at supersonic
speeds. This idea, though, has not been completely accepted in
scientific circles, but if the object did make a mid-flight maneuver
it would certainly bolster the spaceship theory.
Research on Tunguska continues today. Christopher Chyba, of
Paul Thomas, of the University of Wisconsin, and
Kevin Zahnle, of
NASA, have used computer simulations to calculate that a stony
asteroid, about 100 feet across, could produce the right sized blast
when it fragmented and vaporized before hitting the ground. They
point out that iron asteroids are much more dense and would have
probably survived the flight to hit the ground and make a crater.
Recent analysis of resin from trees surviving the blast seem to
confirm the Chyba-Thomas-Zahnle theory.
So what was the Tunguska explosion? Meteorite, comet, anti-rock,
mini-black hole or alien spaceship? It remains a mystery. One thing
is for sure, if the object had hit the Earth a few hours later it
would have come down over Europe and the death toll would have been
a half-million people.
There are probably other Tunguska-type objects, in addition to
asteroids, in space which could do at least the same amount of
damage, if not more. Scientists estimate that an object capable of
making a Tunguska-sized explosion hits the Earth on an average of
once a century. The only questions are: "How soon?" and "Where?"