Every day, between 1,000 and 10,000 tons of material arrive on Earth from space. The quantity is large, but it falls widely distributed and the Earth is practically uninhabited. Only 1% of the planet is populated, so it is normal that we do not perceive that rocks are raining. In our experience, of all this matter there are only the flashes that they produce when they disintegrate against the atmosphere in the form of shooting stars.
But from time to time, a larger rock with catastrophic potential arrives. In 2013, a meteor exploded over the Russian region of Chelyabinsk releasing 30 times more energy than the atomic bomb of Hiroshima. That was the biggest impact of the last century and left broken glass and some minor injuries. A few days ago, according to reports Newscientist, Peter Brown, of the University of Western Ontario (USA), announced that last December another great impact, caused by an object of ten meters in diameter, shook the Earth, but it did so in a region so remote that nobody He saw it.
The explosion of the meteor in the atmosphere occurred on the Bering Sea, near the Kamchatka Peninsula, and released ten times more energy than the Hiroshima bomb. The discovery of that outbreak was possible months later thanks to a system of global monitoring of infrasound, undetectable to the human ear, deployed throughout the world during the cold war to monitor secret nuclear tests.
The discovery of this great impact again calls attention to the difficulty of detecting objects of a few meters in diameter that, if they fall or explode over a population, can have catastrophic consequences. NASA has a mandate from Congress to identify 90% of asteroids with near-Earth orbits of 140 meters in diameter or more. Fifteen years ago, it was estimated that it would be possible to have this catalog ready by 2020, but with current technology it is likely that three more decades will be necessary.
Josep María Trigo, researcher at the Institute of Space Sciences (CSIC) and the Institute of Spatial Studies of Catalonia (IEEC), explains that although most objects of that size are still unknown, for those dimensions of 10 meters and There are several follow-up projects that can locate them a few days in advance. " The Joan Oró telescope of the Astronomical Observatory of Montsec, which contributes to various international asteroid monitoring programs, collaborates in this type of international search. Trigo remembers how in 2008, "the 2008TC3 asteroid was, with 4 meters in diameter, the first asteroid of that size in a direct collision route with the Earth detected with a margin of about twenty hours".
Salvador Sánchez, director of the Astronomical Observatory of Mallorca and member of one of the teams that has more objects with orbits near the Earth has discovered in the world, states that this type of impacts are relatively frequent. "They are light shrapnel that the Earth receives every month. In the US they register a large number of these objects at the moment, but they do not say anything because they fall into the sea or at the poles and the Russians, although not as accurately, they also detect them, but they do not say anything, "he says. "The Earth is a hostile planet and incoming asteroids disintegrate upon entering the atmosphere or bounce," he continues. After many years of detecting larger objects, Sánchez explains that now they have a system of telescopes that continuously observes a sector of the sky 24 hours a day (eye system of God) to capture the arrival of objects of smaller size and power. calculate your orbits at the moment.
In addition to this type of terrestrial projects, in the US the possibility of building a telescope named NeoCam that would be launched into space to accurately complete the catalog of asteroids over 140 meters is already being analyzed. Among the smallest, it has already been possible to detect with an eight-hour margin the impact of an asteroid little more than three meters in diameter. The feat was made possible by the Catalina Sky Survey observatory in Arizona on October 7, 2008. Soon after, the center for the study of NEOs (near-Earth objects) of NASA's Jet Propulsion Laboratory He calculated his orbit and the probable place where it would fall. With that data, it was possible to find fragments of the object in Botswana, just where the scientists had predicted.