All language subtitles for Big Bang in Tunguska (2008)

(dramatic music)

- [Narrator] 30th of June, 1908,

7:14 a.m. local time, Siberia.

The region of Tunguska sees the biggest

explosion in human history.

(explosion booming)

In one hour, the explosion and
the great fire that followed

destroy a region of forest
the size of greater London.

- People who observed that thought

the end of the world had come,

Judgment Day, divine intervention.

(dramatic music)
(explosion booming)

- [Narrator] They say that
the Tunguska explosion

had the force of more
than 1,000 Hiroshimas.

Millions of pine trees,
lodges, and birches

are destroyed by the
pressure wave and the fires.

A shockwave circles the world,

leaving its mark on
seismographs everywhere.

But no one can understand
where it has come from.

It is 20 years before Soviet scientists

discover the true scale of the disaster

and record it on film.

(dramatic music)

Tunguska, as mysterious
as the legend of Atlantis

or the sinister Bermuda Triangle.

Few historical phenomena have
caused so much speculation

as this one day in the
isolated Siberian forests.

An expedition to Tunguska is a journey

into the craziest theories,

and into serious scientific inquiry;

the birth and deconstruction
of a modern legend.

Scientists from many different countries

and disciplines are working to find

the solution to the puzzle; what happened.

For there is still no conclusive evidence

and any number of interpretations.

Was a meteorite the cause of
this terrible destruction,

as most scientists believed?

But then there would be a crater

and no crater has ever been found.

(suspenseful music)

Or was it something quite different?

- [Translator] Of course
my favorite theory

is the one about a spaceship
from another planet.

They wanted to visit us
and have a picnic here.

Then there was an accident

and the spacecraft exploded.

- [Narrator] The theory of
a UFO crash won't go away.

There are several versions.

- [Announcer] Theory 42: the Dropa UFO.

In the Baian-Kara-Ula mountains lived

the diminutive Dropa people,

descendants of an extraterrestrial race

that crashed landed on
Earth many centuries ago.

In 1908 their home planet
mounted a rescue mission.

Unfortunately the rescue UFO crashed

over the harsh taiga landscape.

The Dropa still hope one day

their people will make an
Earth-proof spacecraft.

- There's so little evidence.

It's the lack of hard solid evidence

that makes these theories popular.

- [Narrator] Benny Peiser is
a cultural anthropologist.

He teaches at John Moores
University in Liverpool.

His specialty is natural disasters

and how people cope with them.

- The Tunguska disaster changed our view

of the world and our place in the cosmos,

because until then we thought

that we were basically very protected.

That the universe worked like clockwork

and that nothing dramatic would happen.

But in fact we now know, since Tunguska,

that we are potentially at the center

of cosmic impacts, and they
have happened in the past

and they might happen in the future.

(suspenseful music)

- [Narrator] Imagine the Tunguska blast

happening over Frankfurt.

(explosion booming)

- If a Tunguska-sized
object were to detonate

over a large city, the
entire metropolitan area

would be devastated and
hundreds of thousands

of people would be killed.

- [Narrator] A new generation
of Earth scientists

feel the same, like geologist
Christoph Brenneisen.

(speaking in foreign language)

- [Translator] If it was a meteorite

and the Earth had turned a bit further,

it would have destroyed St. Petersburg.

An hour later it would
have destroyed Helsinki.

One hour later, Stockholm
and after that Oslo.

All these big cities are
on the same latitude,

and that's one reason
it's important to ask

what was really happening here.

- [Narrator] It was this burning question

that first took Christoph Brenneisen

from his castle in Germany
to the Siberian taiga

in the year 2000,

as part of a joint
Russian/German expedition.

Now he's on his way back to Tunguska

to compare the main theories.

If it really was a meteorite,

he should be able to find material

from outer space from soil tests

near the epicenter of the explosion.

Until now, no such
material has been found.

(suspenseful music)

Christoph painstakingly notes

the likeliest places to search.

Maybe his homemade maps will
guide him to a great discovery.

They depict one of the most
isolated regions on Earth.

Beautiful, inaccessible, and unforgiving.

In 1928 Russian mineralogist Leonid Kulik

was the first scientist
to lead an expedition

into what was then a disaster area.

His pioneering work is still the basis

for all later research.

(suspenseful music)

In those days this
territory was even wilder

than it is today.

No one went there if he didn't have to.

Over two decades Kulik and his men

tried hard to find evidence
for a meteorite impact.

(speaking in foreign language)

- [Translator] Kulik explored
this entire area by plane

and mapped everything
in the greatest detail.

He was able to record every tree

in the position where it
lay after the explosion,

and with data like that
it would normally be easy

to show where a meteorite landed.

- [Narrator] Leonid Kulik
used all the latest technology

to aid him in his search for a crater.

He narrowed down his area of interest

to a series of small lakes

near the epicenter of the explosion.

(speaking in foreign language)

- [Translator] During
his research expeditions,

Kulik had some lakes completely drained

to examine their beds,

because he thought that these lakes

could in fact be craters.

But they found tree roots there,

that had until recently been alive.

And they were at the bottom of the lakes.

How could they have got there?

If there had been a meteorite impact

they would have been destroyed.

So Kulik concluded that these couldn't

be meteorite craters.

He was disappointed.

- [Narrator] Maybe Kulik
didn't know what he'd found,

that he'd seen the root of the problem.

Kulik wanted to continue exploring

until he had the solution,
but he never got the chance.

When the Germans invaded Russia in 1941

Kulik volunteered for the Red Army.

He died a prisoner of
the Germans a year later.

(dramatic music)

(explosion booming)

And after the war the focus changed.

The world had seen the atom bomb.

Tunguska had a new meaning for scientists

and a new place in the
science fiction boom.

Apart from real science, nearly 40 novels

have been inspired by
the Tunguska disaster.

One became Andrej Tarkowski's
cinema masterpiece, "Stalker".

There's a meteorite opera from Germany,

and this is Russia's top-selling

M1 Tunguska anti-aircraft missile tank.

If you can't afford a tank,

for just $50 you can have
another kind of blast.

Tunguska Blast, an energy
drink made in Florida

with, they claim, herbs from Tunguska.

Maybe those secret
ingredients are radioactive.

This is a virtual Tunguska computer game

and it's pretty authentic.

It even starts on the
Trans-Siberian Express.

- [Male Soldier] Well comrade,
are you off to Tunguska, too?

- [Female Soldier] Yes.

- [Narrator] Just like geologist's

Christoph Brenneisen's expedition.

Everything about Tunguska is extreme.

The temperature varies between
minus 40 Celsius in winter

and plus 35 in summer.

And it's seriously isolated.

The Trans-Siberian
Express passes more than

700 kilometers away from Vanavara,

the nearest town to the explosion.

So the next stage is by plane.

This is the last bit of
comfort Christoph will enjoy

for quite a while.

Vanavara is the only place
to stock up on provisions

and find the people to take you safely

to the middle of the wilderness.

Back in 1908 Vanavara was a
bustling fur trading post.

Conditions in the taiga,
the Siberian forest,

were perfect for bears,
squirrels, reindeer, and wolves.

The local Evenk shared the
hunting with adventurers

from every part of the Russian Empire.

This was a country for hardy people.

People who didn't mind roughing it.

(bright music)

Even in today's Vanavara

there's still a link
to the events of 1908.

- [Translator] Early in the morning,

before the meteorite landed,

my great-uncle went out
and sat on the steps

in front of his house.

It was summer and he
wanted a little fresh air.

He was sitting there when suddenly

there was this sound that grew

and soon it was very loud.

It made the earth shake.

And the rocky comet
came down, it came down.

There was a loud noise and it landed

17 kilometers from here

with so much force that my great-uncle

was thrown several meters
from the steps to the fence.

(suspenseful music)

- [Narrator] But for one group,

the experience of the
blast was even worse.

These were the Evenk, the
nomadic reindeer herders.

the original people of Tunguska.

(speaking in foreign language)

- [Translator] My
great-grandfather was an eyewitness

of the explosion.

He was in the area where it happened,

but he went away.

If he'd stayed, because this explosion

caused many deaths among the Evenk,

whole clans were killed.

My clan lived with others
here on the Chamba River.

And when the rock fell

it was like a nuclear explosion

that swept everything away
and killed everything.

- [Narrator] But the Evenk
have another explanation.

A shaman pegged Agdy, their thunder god,

to destroy an enemy tribe.

Furious at being misused,

Agdy sent iron birds against the Evenk,

shooting lightning bolts
that split the Earth.

This place is still taboo for the Evenk.

Or was it another kind of lightning bolt?

- [Announcer] Theory 17:
the Tesla experiment.

The famous, or notorious,
scientist Nikola Tesla

is working on a giant transformer
in Wardenclyffe, New York.

While attempting to demonstrate

the unbelievable power of
his artificial light beam,

he makes a colossal error
which Tunguska has to pay for.

- [Narrator] At last Christoph is taking

a Mi-8 long-haul helicopter

with a warden of the
Tunguska Nature Reserve

to the epicenter of the explosion.

(helicopter blades whirring)

Vanavara, the village that was almost

wiped off the map in 1908,
is flourishing again.

Today more than 3,000 people live here,

as hunters, woodworkers, or
administering the reserve.

A bird's eye view of Tunguska,

a completely uninhabited region.

From this perspective the difficulty

of the terrain is clear to see.

Now in mid-May when
the snow starts to melt

these endless swamps are
especially difficult to cross.

A group of scientists,
craftsmen, and hunters

with their dogs are dropped off

at one of the Nature Reserve's lodges.

Christoph flies on with two guides

towards the center of the impact zone.

And here they find Leonid Kulik's hut

on the edge of a vast swamp.

The pioneering Tunguska
scientist was here 80 years ago.

Since then many more have
used it as their base camp.

The roof of Kulik's
main hut has fallen in,

but inside the spirit of
the pioneer still lingers.

(gentle music)

Leonid Kulik may in fact have
got closer than he thought

to finding evidence of the
origins of the blast at Tunguska.

But for the Soviet
scientists who followed him,

everything changed with the detonation

of the first atom bomb.

After the Second World War,

Soviet scientists poured into Tunguska.

They were urgently searching

for a new kind of evidence,

radioactivity or antimatter.

They used powerful magnets
to look for fragments

of extraterrestrial metals.

They did find particles
that could have come

from outer space, but they couldn't find

any definitive cause for
the Tunguska disaster.

Maybe the crazy theorists
had a better idea

for these new times.

- [Announcer] Theory 43:
the time-traveling A-bomb.

In the 1970s a lonely A-bomb got lost.

It fell into a time warp
and popped out again

in distant Tunguska, exploding in 1908

with a pretty respectable bang.

- [Narrator] But when a
real meteorite crashed

into another part of Siberia in 1947,

everything got more complicated.

Because here they found the crater

and parts of the meteorite right away.

(suspenseful music)

In Tunguska it remained
defiantly difficult.

The scientists had to
dig to find out more.

But when the ground wasn't frozen hard,

the summer marshes with
their millions of mosquitoes,

made digging almost
impossible and unbearable.

And yet soil samples had to be taken

in the interest of the Soviet state,

however hard the job.

And soil samples continue to be

the main research tool today.

If there's no cosmic dust on the surface

maybe it can be found in deeper layers

40 to 60 centimeters
down, ground zero in 1908

This is what Christoph
Brenneisen is looking for.

He's here in the month of
May, in the brief period

between the ice and the bogs.

He hopes that what he's
wrapping in his plastic bags

is buried matter from outer space.

There's one other center of interest

for the location of the elusive crater.

After the war, attention narrowed again,

as it had in Kulik's time,

to the lakes that could be
candidates for a crater.

Here at Lake Checko,
scientists have constantly

taken measurements in the water

and in the sediments of the lake bed.

This led to a new theory
from far away Italy.

The research group led by
professor Giuseppe Longo

at the University of Bologna

is now concentrating solely on this lake.

Back in 1991, they were the
first Western scientists

allowed to investigate the impact area,

and they have important new
ideas about the explosion.

(speaking in foreign language)

- [Translator] We believe
that the Tunguska event

was caused by an explosion
in the atmosphere,

either from a rocky
meteorite or from a comet.

The disintegration of the
object in the atmosphere

is the reason why no residue
of an extraterrestrial body

has been found on Earth.

- [Narrator] But they
believe the bigger fragments

must still have left some craters.

They've spent years looking
for matter from space.

Now, Giuseppe Longo, fellow
physicist Romano Serra,

and marine geologist Luca Gasperini,

are determined to solve the
mystery once and for all.

They're extremely well-equipped.

They've already sent divers down

to examine the sediment of Lake Checko

because they're convinced that this

is where they will find the
final answer to the question;

was Tunguska devastated by a meteorite?

The shape of the lake seems
to confirm their hypothesis.

- On one side, with our seismic,
we saw a lot of sediments.

So we were on, I mean, we agreed

with a previous theory
that the lake was very old,

but on the other side the shape
of the lake is very unusual.

It is a funnel, funnel-like
shape, an inverted cone,

50 meter by 350 meter, so it is not usual

for sea burial lake with
our thermo karst lake,

very flat bottom with a couple
of meters maximum depth.

- [Narrator] This is an
aerial shot of the Checko Lake

taken during the annual spring floods.

At first the Italian
scientists only looked

at micro particles from the lake,

but over time they've developed a model

of this entire body of water

that looks remarkably
like an impact crater.

Now they're planning to
drill in the lake bed,

more than 50 meters down.

They're confident they'll find something

- In the bottom which is very important,

close to the center, about
10 meters below the bottom,

we find that a density
anomaly which is very clear

from our seismic data.

And this density anomaly
could be well related

to another pressure,
related to the factor,

or the impactor itself,
which is now buried

below 10 meter of sediment.

- [Narrator] Today, Luca
Gasperini and his colleagues

judge that this lake
is only 100 years old.

Only a new expedition can prove

whether this half frozen lake

does hold the key to the mystery.

Meanwhile, Christoph
Brenneisen is starting

to have his doubts about
the meteorite theory.

So far all his soil
tests have been negative.

He has found no trace
of an object from space.

Now he's moving to a new location

in the south of the Tunguska Reserve.

Because something has been found here

that has set Tunguska researchers buzzing.

It could be powerful evidence
for a quite different theory.

Crossing bog lands still covered in ice,

Christoph reaches the John's Stone.

It was discovered by
John Anfinogenov in 1972.

Christoph is certain that
this rock doesn't belong here.

Its coarse crystalline structure

could only have been
formed deep underground.

There's no connection with
the basalt found hereabouts.

(speaking in foreign language)

- [Translator] A rock like
this could be what we call

an errant block, the sort of
thing we see in North Germany.

But there was never any
classic glacier movement

here like in Germany.

This stone could only
have been brought here

by a great explosion.

- [Narrator] No one's
sure where it comes from,

but it's not from outer space.

And perhaps this man has the explanation.

Wolfgang Kundt is an astrophysicist.

He lives in western Germany,

in the volcanic landscape
called the Eifel.

A few years ago he came up
with a daring hypothesis

that turned the Tunguska
debate on its head.

He believes that the
John's Stone is evidence

of an earthbound cause
for the Tunguska blast.

Kundt has abandoned his
own field of astrophysics

to commit himself to the volcano theory.

(speaking in foreign language)

- [Translator] I was
walking around in Tunguska

when I suddenly thought.

"This is like my home, like the Eifel."

There are plenty of ponds and small lakes,

and there are also drier areas,

fens where you can sink in deep,

like the dry bogs in the Eifel.

The landscape over there
convinced me right away

that we must be dealing
with a volcanic region.

- [Narrator] Kundt's theory is
based on the volcanic origins

of the Tunguska region.

He believes that 100 years ago

molten gases were expelled
through volcanic funnels

from deep inside the Earth.

A look at a cross-section
of the Earth explains it.

Outside the solid inner
core is the outer core,

a layer of molten magma and gases.

Kundt believes that
superheated magma and gases

forced their way through
the Earth's mantle

via subterranean volcanoes.

For thousands of years these
ascending columns of magma

were held back by a thick layer of basalt,

but in June 1908, under immense pressure,

the gas burst through several kilometers

of solid basalt rock.

(explosion booming)

The molten magma remained
beneath the basalt

and only the gas streamed upwards.

A colossal gas storm raged
over the Tunguska region.

Traveling faster than the speed of sound,

the gas reached a height
of 200 kilometers.

The static electricity that resulted

ignited the explosive mix
of methane and oxygen.

(speaking in foreign language)

- [Translator] It was not a single event

but a storm lasting a quarter of an hour.

It absolutely wasn't one event.

All the eyewitnesses clearly relate

that there was a series of loud events

one after another and
that the whole phenomenon

in fact lasted up to one hour.

- [Narrator] The fact that
the event lasted an hour

is a serious argument
against the meteorite theory.

Christoph Brenneisen is now
on the track of evidence

that could support Wolfgang
Kundt's gas explosion theory.

He's looking for remains of trees

from the disaster year of 1908.

There are only a few left
in the thick taiga forests,

but they provide important information.

And they could explain
something Kulik noticed

70 years before.

- [Translator] Professor
Wolfgang Kundt in Bonn

has developed a theory
that a huge gas bubble

blasted them all and upwards,

so that these tree roots were hurled

hundreds of meters through the area

and came raining back down.

You can see many of
these remains near here.

It's quite clearly the
effects of the explosion.

You can still see the
carbonization here on the trunk,

while all the other trees
around here are younger

and show no fire damage.

So you could call this a
foreign body, an interloper.

- [Narrator] Could this
explain the roots Kulik's men

found in the lakes all those years ago?

Mylau Castle in eastern Germany.

This unlikely place houses the world's

only remaining Tunguska Museum.

Gottlieb Polzer,

physicist and passionate
hunter, is its founder.

He organized the first Russo-German
expedition to Tunguska.

He shares part of Kundt's
idea, but he takes it further.

(speaking in foreign language)

- [Translator] I believe
there must have been

a gas explosion there, but
not was just a gas explosion.

It is tempting to posit a variant in which

there was a comet
with at least two cores.

That on entry into the Earth's atmosphere

these cores collided with each other.

- [Narrator] There was an explosion

which unleashed a chain reaction.

Perhaps, Polzer believes,

underground gases were
released as a result

of the impact and were ignited.

(speaking in foreign language)

- [Translator] I believe that a number

of different processes then followed.

For instance, there is a possibility

that there was a mosquito explosion.

- [Narrator] Yes, you heard that right.

A mosquito explosion.

In spite of years of research

we haven't heard anything else

about a mosquito explosion,
but then why not?

After all there are 120 other theories

about the Tunguska blast.

- [Announcer] Theory 79: the black hole.

A plucky little black hole
decided to flex its muscles

and chose Tunguska for the exercise.

With an enormous impact
it thudded into Tunguska,

bored through the earth and
emerged on the other side,

disappearing proud but
unacknowledged in deep space.

- [Narrator] And genuine
scientists seem to share

some extreme theories.

Yuri Lawbin used to
run the Tunguska Museum

in the Siberian city of Krasnoyarsk,

until he ran out of money

and someone stole his
two-ton meteorite, he said.

Now he only has little specimens,

but he makes big
announcements about Tunguska

that always manage to
attract the headlines.

- [Translator] It was
here, not in Vanavara,

in the southern marshes
where everyone else looks.

It was a giant comet.

According to my latest calculations

it weighed a billion tons.

Had destroyed a
technological object, a UFO.

How do we know this?

Because we have found a
photo from outer space.

This is the actual site where
the destruction took place.

You can't find destruction like this

in the southern bogs near Vanavara,

and there never was any.

This destruction is proof.

And these are the traces left

by the takeoff of the spaceship.

It was 25 square kilometers in size.

It turned, it flew towards
the comet, and it exploded.

Why, here's the problem.

If the comet weighing a billion tons

had passed near Earth it
would have brushed the Earth

and all the dust would have
climbed into the atmosphere.

The atmosphere would have turned dark.

The sun would have been covered,

and we, imagine, we might
never have been born.

- [Narrator] Close to the
take-off point of the UFO,

Lawbin has found a small
piece of the spacecraft.

A clump of ferrosilicon, he says.

If we accept this archeologist's theory,

an alien power sacrificed
itself for humanity.

A gigantic spaceship and it's heroic crew

saved us from the killer comet.

Yuri Lawbin's is not the
only extraterrestrial theory.

- [Announcer] Theory 92: a
message from outer space?

In 1883 the volcano of Krakatoa erupted.

Aliens in the Swan constellation
saw the columns of smoke

and took them as a pathetic
attempt to get in contact.

They replied with an
enthusiastic laser beam

that made Earthfall in Tunguska.

Unfortunately humanity
failed to understand

this powerful message.

- [Narrator] Back to the present,

where more and more
expeditions are setting off

for the region of the explosion.

Maybe it has something to do

with the beauty of the landscape,

or maybe it's the fact that
humans like solving mysteries.

This archive footage was shot in summer.

Brenneisen's expedition
is taking place in May.

In spring some of the rivers
are nearly impassable.

(dramatic music)

The Churgim waterfall.

It's accessible in this 1950s summer.

For Christoph's group
it's a formidable barrier.

There's no perfect season
for exploring the taiga.

Summer brings new dangers, like
some very poisonous snakes.

Near Churgim waterfall
geologist Valentina Bykova

shows her German colleague more remains

from the year 1908.

(speaking in foreign language)

Deep in the Tunguska
forests you can still find

a few carbonized tree
stumps still standing

from the 1908 explosion.

(dramatic music)

That evening Valentina and Christoph

examine their freshly gathered samples

of soil, stones, and moss.

Though Christoph may
be becoming a skeptic,

Valentina still believes
that the explosion

was caused by a meteorite.

She's convinced it's just a matter of time

before scientists find the cosmic dust

that will be proof.

And she certainly knows
about other strange phenomena

near this camp at Pristan.

(speaking in foreign language)

- [Translator] About 17 or
18 kilometers from here,

from the Pristan camp, on the Kulik road

in the direction of Vanavara,

there's a place called Idol Mountain.

Very strange things happen there.

Electronic quartz watches stopped working.

The display goes out.

Quartz watches stop, but
mechanical watches keep going.

And there have been cases of
mass psychosis at this place.

People seem to have a nervous collapse

and they start to get angry.

- [Narrator] There are many
examples of strange phenomena

in Tunguska, but a lot
of them can be explained.

Christoph Brenneisen is on his way

to the highest point in the impact area.

Something strange happens here, too.

(suspenseful music)

(speaking in foreign language)

- [Translator] This is Mount
Farrington, 519 meters high.

It makes compass needles turn.

North becomes south, east becomes west.

You can't use a compass or GPS.

- [Narrator] The phenomenon
of the crazy compass

turns out to be not so
mysterious after all.

The stone on the mountain
is simply highly magnetic.

This geological phenomenon is also seen

in other parts of the world.

And yet Mount Farrington
is one of those places

at the epicenter of the explosion

that has attracted scientists for decades.

And maybe that's partly
because of the fantastic views

it offers of one of the most
remarkable places on Earth.

(surreal music)

But of course the scientists
don't really come here

for such romantic reasons.

People have long said
that plants and trees

grow exceptionally fast here,

and according to local people

the soil of Tunguska is an
extremely effective fertilizer.

But there's more.

Soviet scientists in the Atomic Age

took up a new study.

They became interested
in studying the mutations

in flora and fauna in the Tunguska region.

In the 50s they discovered that the trees

had broader annual rings
since the year 1908

than in the years before the explosion.

And Christoph himself has even discovered

a genetic mutation in the
growth of pine needles.

(speaking in foreign language)

- [Translator] I have here
needles of the Pristan pine

that usually grow in even numbers.

Two, four, but not what you see here.

For example, five or even three.

So there will be a lot of
things to look at here.

Even the magnetic storms
we can observe here

that put our compasses and GPS devices

temporarily out of action
could trigger a mutation.

Of course, there are also mutations

that take place because of
normal stresses in nature,

like changes in food supply,
humidity, cold, et cetera.

But the mutations pile
up to such an extent

in the event region that you start

to wonder about other causes.

- [Narrator] Mutations
and increased growth

can also be seen after an atomic explosion

or radioactive contamination.

So Soviet scientists
measured their tree rings,

burned them and analyzed the ashes.

They couldn't find any clear evidence

of a nuclear explosion or
large-scale radioactive damage.

But that has not discouraged
the nuclear disaster fans

among the Tunguska theorists.

- [Announcer] Theory 21: atom bomb test.

Europe at the beginning
of the 20th century.

It started with a secret
military collaboration

between the Russian Tsar

and his cousin the Prussian Kaiser.

They would develop an
enormously powerful atom bomb.

Unfortunately, the bomb's developers,

together with their blueprints
and the whole of Tunguska,

went up in the very first test explosion.

And the emperors were soon in no position

to commission any further experiments.

- [Narrator] Sandia National Laboratories

in Albuquerque, New Mexico
is a weapons research center.

Here Mark Boslough has developed

the most sophisticated of all models

to explain the Tunguska phenomenon.

He believes he can answer the
question once and for all.

- The Tunguska explosion, I think,

was caused by the impact of a large comet

or asteroid with the atmosphere.

It came into the
atmosphere, it broke apart,

it exploded before it hit the ground,

and the explosion
generated a lot of light,

and a lot of heat, and it
generated a strong blast wave

that created winds at the surface

that were so strong that
they blew down trees

and the heat ignited some of these trees

and created a fire.

So I think the Tunguska
event is fully explainable

in terms of the impact
of an asteroid or comet.

- [Narrator] Mark Boslough's
model of a meteorite explosion

at an altitude of five to
10 kilometers is not new.

What is new is that Boslough can test it

with a state-of-the-art
computer simulation,

without leaving the lab.

- I think the reason there was no crater,

no obvious crater, was
because the comet or asteroid

expended all its energy and
exploded at high altitude.

So there was really nothing
left to hit the ground.

Crater-forming impacts
require that something solid

actually collide with the ground.

It doesn't appear that that happened

in the case of Tunguska.

- [Narrator] So there's
no crater to be seen.

But according to Boslough,
there's no need for a crater.

What scientists did see
was knocked over trees.

Kulik's archive photos and film

provide a great deal of information.

They've inspired generations of scientists

to use the pattern of tree collapse

to establish the exact
position of the explosion.

In the 1950s models were
tested in a pressure chamber.

(surreal music)

This model clearly shows an area

in the middle of the blast

where the trees remained standing.

An extremely convincing
argument for no crater.

And Mark Boslough has fed this data, too,

into his computer.

Here is a mid-air explosion
seen from the side,

with its blast wave.

You can clearly see how it spares

the trees immediately below.

- Our simulations show
a very strong blast wave

coming down from the sky,

and it's it's radiating
from a place in the sky

and as that blast wave hits the ground

there's a component of very high wind

blowing radially outward from the center,

from ground zero and
so that's the direction

that the trees blow down.

So they're basically laying
down in a radial pattern

directed away from ground zero.

- [Narrator] And that would
explain a strange phenomenon,

why some of the trees remain standing.

They were right underneath the explosion.

Stripped of their
branches, but still there.

And to provide the final explanation,

a scientist must also take into account

the strange light phenomena
connected to Tunguska.

From Moscow to London,

for three nights after the 30th of June,

people could read their
newspapers outside at midnight.

A hundred years on, we know
that a giant dust cloud

from Tunguska was
carried by the east winds

of the thermosphere across Europe,

reflecting the sun's
light back down to Earth.

Mark Boslough sees this
phenomenon as further support

for his meteorite theory.

He believes his computer
model can explain that too,

using information from the
other side of the solar system.

- We modeled the impact of
Shoemaker-Levy 9 on Jupiter,

the comet that collided
with Jupiter in 1994.

And one of the outcomes of our model

was a giant ballistic plume

that was ejected into space.

And that plume rose to
a very high altitude,

something like 3,000 kilometers,

and then collapsed on top
of Jupiter's atmosphere.

And it had a lot of
dust and material in it

that reflected sunlight.

And we think a very similar
phenomenon occurred at Tunguska.

(explosion booming)

- [Narrator] But
astrophysicist Wolfgang Kundt

doubts that a meteorite explosion

could cause three nights as bright as day

across all Europe.

He believes this phenomenon
can only be explained

by light volcanic gases.

(speaking in foreign language)

- [Translator] For that you need particles

in the high atmosphere,

where no comet dust and no
asteroid dust can remain.

Up there you get light ice crystals,

like the ones gently falling on our heads.

They can be carried up there by hydrogen

and helium and methane.

They can stay up there for days.

- [Narrator] Whichever piece
of evidence you examine

under the microscope,

the supporters of the meteorite theory

will claim it for themselves.

And so will Wolfgang Kundt for
his underground gas theory.

Incidentally the meteorite people

are clearly in the majority.

And the team from Bologna are
facing their moment of truth.

They plan to test their theory

right there on location.

- You can easily test
it, I mean you go there,

you dig, and you find yes or
no, is a meteorite or not.

(speaking in foreign language)

- [Translator] If it had fallen to Earth,

we would have found something.

There have been so many
scientific expeditions

and scientists, I think the
Earth simply barged it away.

The world is round and in
those days it was healthy,

not like today.

- [Translator] An explosion
from inside the Earth,

a volcanic explosion,
for me that's the only

interpretation that is consistent

with all the facts we
have in our possession.

- [Narrator] But for
some like Benny Peiser,

that's not really the point.

- Regardless of what actually
happened in Tunguska,

even if it wasn't an asteroid,

asteroids actually exist
and asteroids actually

hit the Earth and actually
explode in the atmosphere.

We observe asteroids exploding

in the atmosphere all the time.

(dramatic music)

(explosion booming)

- If it does collide with the Earth

it's probably going to be over the ocean

or over in an uninhabited place.

There are so many other natural disasters,

such as hurricanes, volcanoes,
earthquakes, tsunami,

and so forth that have a
much, much higher rate of

and a much, much higher
probability of happening

and creating catastrophes.

And so in a relative sense
these aren't something

that we should really spend
a lot of time worrying about.

- [Narrator] But Mark Boslough
has never been to Tunguska.

When you have, like Christoph Brenneisen,

it doesn't let you go.

And luckily for him there's
no sign of a solution soon.

- [Translator] I came here as a supporter

of the meteorite theory, but
I've had to change my mind.

I have no answer, science has no answer.

There are fashions that come and go.

One moment it's a meteorite.

One moment it's a comet.

Or it has an endogenous earthbound cause.

I haven't been able to solve the mystery,

and I don't think anyone
else will in the near future.

- [Narrator] Even after a hundred years,

debate about the Tunguska disaster

shows no sign of slowing.

In fact, it's getting livelier than ever

and Tunguska is getting ready

for still more expeditions.

Whether they'll find
anything remains to be seen.

And so for the time being
the Tunguska legend lives on.

That's what legends are for.

(suspenseful music)