In the beginning of 1991 first results of the analysis of wood samples brought to Croatia from Tunguska were available thanks to cooperation between the researchers from Tomsk University, Bologna University and Visnjan Observatory. The samples were collected during the 1st International Tunguska Expedition (ITE 1990).
After the first particles trapped in resin were found, team from Bologna University went to Siberia in 1991, bringing back additional samples, in which, until now, another 5000 particles have been found and analyzed.
 |
 |
 |
 |
Image 1: Sawing a radial sample of the tree in whose resin the first particles linked to Tunguska body have been identified. K. Korlevic (left).
SEM microscopy has proved itself to be an extraordinarily powerful mean of analysis of particles entrapped in tree resin and in identifying the body which on 30th Jun 1908 destroyed 2150 square kilometers of Siberian forests. First published results about this method are from 1992.
About the same time, first articles which describe the Tunguska event in a different way and put it into context of NEO threat appear. Unfortunately, these publications remain confound to the astronomical community of that time.
Image 2 (above): A node of Siberian pine, surrounded by resin, in which the first particles of several microns in size have been found. Longer, red line is the year 1900, and in the 1908 line a visible wood tissue trauma exists.
Photo by Menotti Galli.
Image 3 (left): First photographs of the resin trapped particles, taken in 1991.
Photo by Giovanni Valdre’.
