3.12: What happened at Tunguska? (scientific skepticism)
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This article is from the Scientific Skepticism FAQ, by Paul Johnson Paul@treetop.demon.co.uk with numerous contributions by others.
3.12: What happened at Tunguska? (scientific skepticism)
At 7:17 in the morning of June 30th 1908, close to the Stony Tunguska
River, on the Central Siberian Plateau, a huge air explosion occurred.
The explosion was powerful enough to be heard hundreds of miles away.
The area around the Stony Tunguska River is inaccessible and consists
mostly of bogs and pine forests. The seismic shocks from the
explosion were detected around the Earth. The London Times of July
4th, 1908 reported "The remarkable ruddy glows which have been seen on
many nights lately...seen...as far as Berlin."
When an expedition eventually reached the epicentre of the explosion
they found that the pine trees had been pushed over, pointing away
from the centre. The trees directly under the explosion remained
standing. Some small craters *were* observed at the time but have
disappeared over the years due to the boggy land. The pattern is now
recognised as being similar to that produced by an air-burst nuclear
bomb.
Currently the event is usually explained as a small, unnoticed, comet
hitting the upper atmosphere somewhere over China and finally
exploding a few seconds later above Tunguska. A number of other
explanations have been offered...
* an atomic explosion. Some reports collected some time after the
event describe a typical mushroom cloud. The problem here is
that such clouds are typical of large explosions due to any cause
- they are not peculiar to atomic explosions. There is also the
difficulty in explaining how the Russians first developed and
then forgot the technology when it would have been very useful in
two major wars!
* a small black hole weighing a few million tons passed through the
Earth. The other entry/exit point was unnoticed as it was in the
ocean. Steven Hawking has now shown that black holes of such a
size have very short lives in cosmic terms due to an
`evaporation' effect.
* a small anti-matter meteor. This now seems very unlikely with
the recent discovery of large amounts of inter-stellar matter in
which, although still close to a vacuum, is quite sufficient to
erode any small amount of anti-matter quite rapidly. In addition,
the very existence of anti-matter in any sizable amounts in our
universe is now thought to be very unlikely.
* an alien spaceship, damaged and out of control, exploded during
an emergency landing. There is no supporting evidence for this
apart from eye witness reports of the vapour trail caused during
the objects passage through the atmosphere showing a distinct
`bend', which is supposed to be due to a course change. Such
bends can also be found in the vapour trails of aircraft which
can be seen to be flying straight and are caused by winds in the
upper atmosphere.
The event is not such a mystery as some suppose. In 1969 a Soviet
periodical published a bibliography of more than 1000 entries. Though
these are mostly in Russian it is not difficult to find references in
western scientific publications. `Nature' has published a number of
papers covering most of the above explanations.
References
John Baxter and Thomas Atkins, "The Fire Came By", Futura
Publications Ltd, 1977, ISBN 0 86000 7540 0
Oliver, Charles P. "The Great Siberian Meteorite," Scientific
American, Vol. 139, No. 1(1928), 42-44
Growther, J.G. "More About the Great Siberian Meteorite,"
Scientific American, Vol. 144, No. 5 (1931), 314-317
Zigel, Felix. "Nuclear Explosion over the Taiga: Study of the
Tunguska Meteorite," Znaniye-Sila, No. 12 (1961), 24-27 [English
translation available from Joint Publications Research Service,
Washington, DC., JPRS-13480 (April 1962)
Parry, Albert. "Russia's Rockets and Missiles" Macmillan 1962,
pp 248-267
Cowan,C.,C.R. Atluri and W.F. Libby. "Possible Anti-Matter
Content of the Tunguska Meteor of 1908," Nature, Vol. 206, No.
4987 (1965), 861-865
Jackson, A.A., and M.P. Ryan, "Was the Tungus Event Due to a
Black Hole?", Nature, Vol. 245, No. 5420 (1973), 88-89
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