Free Astronomy Magazine September-October 2019

29 SMALL BODIES to a hypothetical cen- ter, which the expedi- tion was unable to reach. The goal of reaching the epicenter was instead pursued the following year, with a new expedition financed by the Acad- emy of Sciences, and was then again in 1929. On those occa- sions, many cavities and small depressions were identified that could have concealed meteorite fragments, but, despite multiple excavations, no mete- orite was ever found. Kulik continued his ex- ploratory activity until the final expeditions of 1938 and 1939. Two years later he died during the siege of Leningrad, and the war would prevent other explorers from reach- ing the epicenter. The expeditions then resumed in the 1950s and there have been numerous additional studies up to our current time, with new studies still being organized. From the pio- neering studies of Kulik, the overall picture T he growth of the rings of the few surviving trees, found within a few kilo- meters of the epicenter of the Tunguska event, shows a depres- sion that begins the year after the event and contin- ues for another 4-5 years. Below, the area devas- tated in 1908 as it appears today.