By Jane Fryer
Last updated at 9:13 AM on 03rd July 2008

At 7.17am on June 30, 1908, a towering column of light, bright as the sun
and blueygold in colour, hovered in the sky above the dense forests of
Siberia.

Minutes later came a blinding flash, a wall of blistering heat, a pillar
of
fire and a staggering explosion which flattened trees and bushes, and
burned everything in its path.

'The sky split in two and fire appeared high and wide over the forest,' a
member of the local Evenki tribe remembered.

'The split in the sky grew larger, and the entire northern side was
covered
with fire.

'At that moment I became so hot I couldn't bear it, as if my shirt was on
fire. I wanted to tear off my shirt and throw it down, and then the sky
slammed shut. A strong thump sounded and I was thrown a few yards.'

The Evenki tribesman was one of the lucky ones. The blast was 1,000 times
more powerful than the atomic bombs dropped on Hiroshima and Nagasaki.

Explosions could be heard more than 600 miles away, tremors hurled people
off their feet more than 40 miles away and more than 80 million trees
covering 830 square miles were flattened.

The Tunguska Event - as the devastation became known - went down in
history as the greatest cosmic impact of modern times.

A century on, scientists are still bickering about what really happened
near the Podkamennaya Tunguska River in Russia.

Was it an asteroid - a lump of rock and iron the size of a football
stadium which hurtled towards the earth at a speed of seven miles a
second?

Or perhaps a comet - made of ice and mud? Or an 'earth burp' - a
sudden
gigantic expulsion of methane from the ground? Or maybe a collision with a
'smallish' black hole?

Or was it in fact - as a staggering number of people really do seem to
believe - the work of a bunch of incompetent aliens trying, rather
clumsily, to get in touch?

Perhaps by the end of the week, we'll have a better idea. Because in a
desperate bid to solve the mystery once and for all, Russian scientists at
a special anniversary symposium being held in Moscow have spent the past
few days chewing over the options.

And, due to the lack of an obvious crater, debris or, indeed, any firm
evidence that something solid did actually crash to earth, they're
considering every possibility - from asteroids and comets to some rather
more colourful schools of thought.

Such as that of Yuri Lavbin, head of the Tunguska Space Phenomenon Public
State Fund, who blames it all on aliens and, before you scoff, insists he
has the evidence to prove it - wreckage from their spaceship that he
says
he discovered four years ago.

And even the UFO conspiracy theorists are fiercely divided as to why,
precisely, extraterrestrial creatures would have wanted to annihilate a
great swathe of barely populated Siberian forest.

Some claim they were friendly aliens, keen to help out vulnerable
Earthlings.

So the explosion was the result of an alien weapon shooting down a
meteorite which would have caused far more devastation if it had been
allowed to impact.

Others say it was the result of an exploding alien space ship. Or an alien
attack.

Although, if so, why Siberia? It's not exactly a prime spot. Maybe they
set
their watches too fast - just four hours later and London, which lies at
the same latitude, would have been razed and millions of people would have
been killed.

Experts say that an explosion of that size would wipe out an area
equivalent to everything within the M25.

Yet another faction insist it was all a dreadful extraterrestrial cock-up,
and that residents on a far off planet mistook the massive 1883 Krakatoa
eruption as a cheerful communication from Earth.

Or - please suspend belief a little longer - the devastation of 80
million trees was the result of the aliens' over-enthusiastic response
with
a laser probe.

Whatever the cause, the explosion sent an atmospheric shockwave twice
around the world and turned night into day across Europe.

Britain was lit for several days by a beautiful white and yellow sky,
bright enough for midnight games of cricket and golf across the country.

This phenomenon is now thought to have been due to sunlight scattered by
dust from the fireball's plume.

In a letter to a newspaper, one reader wrote: 'I myself was aroused from
sleep at 1.15am, and so strong was the light at this hour, that I could
read a book by it quite comfortably.

At 1.45am, the whole sky was a delicate salmon pink, and the birds began
their morning song.'

Shockwaves

Extraordinarily, despite the global shockwaves, dust particles, midnight
sun and cricket matches, no one bothered to pop up to Siberia to see what
had happened for 13 years - the Russian czars weren't that bothered
about
the backward Tungus people.

But finally, in 1921, Russian mineralogist Leonid Kulik visited the
region,
interviewed local eyewitnesses, decided a meteorite must have been the
cause and persuaded the Russian authorities to fund an aerial survey in
1938.

This revealed how the flattened trees were angled away from the epicentre
of the explosion over a 30-mile-wide zone, in the shape of a butterfly -
but there was no crater.

Back in Moscow, the debate rages on. If idiot aliens are just too much to
swallow, the Russian symposium will also be considering whether an
American
scientist called Nikola Tesla had anything to do with it all.

Apparently, he'd developed a 'death ray' (a particle beam weapon which
travels at the speed of light) at about this time and had been testing it
out in a rather cavalier fashion.

Last Thursday, three Italian experts insisted that Lake Cheko, five miles
from the epicentre of the blast, was the missing impact crater.

And if it was, after all, a meteor? Look on the bright side. According to
NASA, midsize meteor strikes occur only once every 300 years.

And given that only a tiny fraction of the earth is heavily populated, and
70 per cent is covered with water, the odds of a direct strike on a
populated area are pleasingly remote.

Whatever it was - alien incompetence or bog-standard meteorite - the
Tunguska Event remains one of modern humanity's narrowest escape from
extraterrestrial destruction.

And the spaceship wreckage? Well, it could be an uncanny coincidence, but
it turns out the Tunguska site is downrange from the Baikonur Cosmodrome
and, over the years, has been repeatedly scattered with Russian space
debris.

Meanwhile, the local community have very sensibly dismissed it all as a
load of rubbish, and marked the 100-year anniversary of the explosion by
unveiling a statue to the Evenki god of thunder. But the UFO debate rages
on.

http://www.mailonsunday.co.uk/sciencetech/article-1031310/Was-massive-blast-Siberia...

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