Sunday, 29 June 2008

The Tunguska Event at 100.

On June 30, 1908 (NS) *, at 7:14 A.M., a massive explosion occurred in the taiga forest deep in Siberia, near the Tunguksa river, leveling trees up to 30 km away from the centre of the blast, and causing global climatic and geophysical sequelae.

This event has captured the enduring interests of scientists, both professional and laymen, and has intertwined itself in popular culture, science fiction, and conspiracy theories.

The devastation, as recorded by Leonid Kulik during expeditions beginning in 1921, would remain unparalleled until the atomic bombings of Hiroshima and Nagasaki in 1945.

While the immediate effects of the explosion were confined to the swamps and forest within 40-50 km of the centre, the blast caused a number of global atmospheric phenomena, e.g., noctilucent clouds which made it possible to read the newspaper, or take photographs at night, in London. Seismometers read tremors that would register in the 5s on the modern Richter scale, and microbarometers recorded a shock wave that traveled around the globe at least twice before dissipating.

The local tribesmen thought that the wrath of the thunder god Agdy had been brought down by a neighbouring tribe's shaman. Peasant villagers sent a delegation to the local archpriest to ask how the preparations for the end of the world were coming along. Scientists in the European capitals tried to connect the phenomena of the atmospheric and geologic activities.

In this modern day of instant access to all manner of information (I am currently watching lightning-strike data superimposed on a Doppler radar loop, as storms approach from the west), it is hard to imagine that an event of the magnitude of Tunguska could occur without some knowledge of just what happened.

Over the next few days I will be presenting some further discussion regarding the event, which connects to several points of our collective Victorian/steampunk experience.

* The local date was June 17 using the so-called "Old Style" Julian calendar. The majority of the west had already adopted the Gregorian (or "New Style") calendar, but the Russians, being, well, Russian and Orthodox, did not take well to innovation, especially innovation coming from the Bishop of Rome. But that is clearly a story for another day.


Hotspur O'Toole said...

Perhaps not coincidentally, the last episode of Scientific American I picked up contained a lengthy article on Tunguska. I just read it this weekend, unwittingly participating in the anniversary, I suppose.

The article was written by By Luca Gasperini, Enrico Bonatti and Giuseppe Longo-- apparently they are back in the Tunguska area searching for fragments of the object that caused the devastation. I look forward to reading more on this subject! Do keep us informed of developments.



Kate Nicholas, F.R.S. said...

Yes, I read the Sci Am article as well. I will be discussing the findings from the Bologna team (seriously; from the University of Bologna) later. Their theory that Lake Cheko is the impact crater holds merit, but is not without controversy.

The Sci Am piece is interesting, but not terribly in-depth. The illustrations, however, were well-done, except for that horrible photomontage at the beginning depicting Semen Semonov (again, seriously) at Vanavara. The explosion effect was "special", to be sure.