The US National Aeronautics and Space Administration (NASA) reported that a group of scientists from 9 countries, led by experts from Russia, determined the mass, speed and brightness of fragments of a meteorite that fell on the territory of the Chelyabinsk region in February of this year.
NASA specialists took part in this study under the guidance of Olha Popova, senior researcher at the Institute of Dynamics of the Geospheres of the Russian Academy of Sciences, ITAR-TASS reported. The co-authors of the research are also scientists from Chelyabinsk State University, such as Alexander Dudorov, Sergey Khaibrakhmanov and Alexander Mayer.
Samples of fragments of a meteorite, collected shortly after the fall, were provided for study by various laboratories by Alexander Dudorov, a professor at Chelyabinsk State University. An analysis of the fragments found showed that the minimum mass of precipitated meteoritic material was 4000-6000 kilograms. In addition, more than 70 percent of the initial mass has evaporated.
After examining the wreckage of the Chelyabinsk meteorite, as well as video recording of their fall to the Earth, the researchers found that a “cosmic guest” weighing about 11 tons entered the Earth’s atmosphere at a speed of 19 km / sec. already increased to 30 km / s. The study, published on November 6 in the scientific journals Nature and Science, also reported that many fragments burned in the atmosphere before they reached Earth.
According to scientists, at the time of passage, the meteorite reached a peak brightness that exceeded 30 times the brightness of the Sun, which caused temporary blinding of people and even burns. The maximum luminescence was noted at a height of about 30 kilometers above the Earth's surface. According to estimates by an expert group of Czech researchers led by Jiří Borovičky, the energy of a Chelyabinsk meteorite was about 500 kilotons in TNT, which is 100 times more than the Sutters Mill meteorite in California last year. One of the unexpected findings was that the asteroid hitting the Earth had a similar orbit with the previously known near-Earth asteroid 1999NC43, and the researchers are confident that both asteroids were once part of one larger asteroid before 1.2 million years ago not divided, for example, with a close passage near the Earth, reports gazeta.ru. The rest can still be one of near-Earth objects.
According to the researchers, the collision of celestial bodies weighing over 10 thousand tons with our planet theoretically can occur approximately every 30 years, and not 150, as previously assumed. The basis for this conclusion was the data on the frequency of combustion of meteorites in the Earth’s atmosphere. Therefore, scientists led by Professor Peter Brown of the Canadian University of Western Ontario have refuted previous estimates of experts, according to which the probability of a meteorite similar to that of Chelyabinsk falling to Earth is very small in the near future.
Recall that the Chelyabinsk meteorite, about 17 meters in diameter, entered the Earth’s atmosphere on February 15 and broke up into a huge number of fragments that hit the territory of the Chelyabinsk region, as well as the Tyumen, Sverdlovsk, Kurgan regions and Bashkiria. According to scientists, he was the largest celestial body that fell to the Earth since 1908 after the fall of the Tunguska meteorite. In mid-October, divers took from the lake Chebarkul in the Chelyabinsk region the largest fragment of the meteorite. His weight was about 570 kilograms. It was not possible to measure the exact weight of the fragment, because at the time of weighing the scales broke under it.
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