The risk of dangerous meteorites is 10 times higher than ... - The Mundo.es

reminder. So a team of researchers define the explosion caused by the meteorite that on February 15 caused more than a thousand injured in Chelyabinsk (Russia) and that was the biggest recorded impact on Earth since the so-called Tunguska event (in fall 1908 of an object, which no remains were found, caused a huge crater in an unpopulated area of ??Siberia).

According to a study published this week in Nature and led by researchers at the University of Western Ontario (Canada), the number of meteors with a size similar to Chelyabinsk (about 19 meters) that pose a threat to Earth could be ten times greater than previously thought. Peter Brown and his colleagues have also calculated the total amount of energy released by the explosion of the meteorite, which was able to break thousands of glass windows and doors. Its impact, compared, was equivalent to an explosion of 500 kiloton (estimated to the destructive power of the atomic bomb dropped on Hiroshima in 1945 was 15 kilotons).

is one of three investigations into the meteorite match this week in the pages of Nature and Science, considered the two most prestigious journals. And, unlike what happened in Tunguska meteorite fell Chelyabinsk near a densely populated area in the XXI century, so that the numerous videos and photographs taken by surveillance cameras and mobile phones of citizens, along with abundant rock fragments collected in the area, are allowing to reconstruct in detail what happened that day and proceeded to investigate where this meteorite. Several research teams around the world are studying this episode and the likelihood that an object of this type to fall back on Earth. And, while scientists monitored and have more or less eye on large asteroids that could pose a threat, the smallest.

“If Humanity does not want to end up like the dinosaurs, we have to study such events in detail” , warns resounding Qing-Zhu Yin, professor of planetary science and Earth the University of California, and coauthor of the study published this week in the journal Science .

After the explosion, the authors of this study, led by Olga Popova, of the Russian Academy of Science, visited fifty towns nearby to assess the impact of the fall. As tested, the blast caused damage in areas up to 90 miles away.

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regard to their age, they propose that this chondrite has 4.452 million years old.

Based on the images recorded by video cameras from different angles, the team led by Popova estimated the asteroid entered Earth’s atmosphere at a speed of 19 kilometers per second , slightly faster than previously estimated.

impact caused it a piece of rock about 20 meters in diameter that fragmented when it was at 30 miles high. It was at that moment when it exploded and reached its peak brightness (perceived as 30 times brighter than the Sun, causing severe burns in some people).

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After the explosion, three quarters of the evaporated rock . Most of what remained became dust and only a small fraction (between 4,000 and 6,000 kilograms, ie, equivalent to 0.05%) dropped like meteorite.

Rock The largest fragment recovered until now weighs 650 kilograms and was rescued from the lake last October. Before collected numerous small fragments that have been analyzed by other researchers, although many of them fell into the hands of the meteorite hunter for the sale of these pose rock remains a lucrative business.