Hall 5: The fall of the Chelyabinsk meteorite, in the southern Ural region of Russia, on 15 February 2013, was the most spectacular cosmic event of the last decades.
Following this incredible event, researchers from all over the word, including those at the NHM Vienna, have started to study this event and the recovered samples.
The fall of the Chelyabinsk meteorite, in the southern Ural region of Russia, on 15 February 2013, was the most spectacular cosmic event of the last decades. The entry and explosion of the meteoroid were recorded by dozen of cameras, especially by dashboard cameras that are fitted at the front window of cars in Russia and that are used to record traffic incidents. This was the first time that such an event was documented from a more than dozen different angles, allowing scientists to precisely back-calculate the meteorite's flight path and its orbit when it was still a small asteroid (or meteoroid) orbiting in the solar system. The spectacular explosion in an airburst and the resulting shock wave caused substantial damage to a number of buildings and injured over 1,500 people (mainly from broken glass windows) in the city of Chelyabinsk, about 60 km from the explosion site. In the next days and months, thousands of stones were recovered, mainly small stones, in the range of a few grams. Only recently, in October 2013, the largest stone of this fall, weighing ~650 kg, was recovered from Lake Chebarkul. By comparison, this large stone, now displayed in the Chelyabinsk State Museum of Local History (Russia), is just twice the weight of the large Knyahinya meteorite that is on display in the world-famous Meteorite Hall at the Natural History Museum (NHM) in Vienna and that was for a long time the largest known stony meteorite.Following this incredible event, researchers from all over the word, including those at the NHM Vienna, have started to study this event and the recovered samples. One of the most interesting finding concerns the energy of the airburst explosion that has been estimated by a group of colleagues from Canada and other countries to be ~400-600 kilotons TNT equivalent. [The last cosmic event greater than this in magnitude was the Tunguska event, in 1908, when an explosion occurred over an inhabited region of Siberia, generating an energy estimated at 5-15 megatons TNT, knocking down tens of millions trees.] From the explosion energy, the size of the meteoroid has been estimated at ~19 m diameter, a number that is in agreement with values derived from our radionuclide investigations (see below). Although a mass of ~12,000 tons is estimated for the meteoroid, in total only about one ton of meteorites were recovered on the ground. Only a few days after the fall, the NHM Vienna was able to acquire a dozen small stones, weighing up to ~10 g, and to immediately start some scientific investigations. More recently, several more samples of the Chelyabinsk meteorite were acquired, including a large and very nice individual fragment weighing 387 g. This sample is now, exactly one year after the fall, on display in the Meteorite Hall in showcase 85, in the central part of the display, next to the historically important and precious Ensisheim samples (a fall that occurred in 1492).