Chelyabinsk Eyewitnesses Support Researchers Resolve Meteor Mysteries
STREAKING METEOR: M. Ahmetvaleev took this photograph of a meteor streaking more than Chelyabinsk, Russia on February 15, 2013.
Picture: M. Ahmetvaleev/NASA
On February fifteen, 2013, people in close proximity to Chelyabinsk, Russia felt the ground shake, smelled the sour stench of sulfur, read windows shatter into sprays of glass and experienced to search absent from a fireball in the sky so bright it hurt their eyes. The meteor that caused all this havoc largely dissolved into a cloud of dust throughout its passage by means of Earth’s environment, so experts are turning to clues on the floor and the memories of eyewitnesses to piece together what took place that working day. Around one,five hundred folks ended up hurt, though no one particular was killed. In the city of Chelyabinsk alone, more than three,five hundred properties ended up destroyed, and the scientists identified shockwave destruction as far as a hundred kilometers absent from the affect internet site.
Based on testimony from folks near the affect zone as nicely as the copious movie footage caught by residents’ dashboard cameras and security online video feeds, experts have calculated the exact trajectory of the inbound Chelyabinsk meteor, as well as the power of the atmospheric explosion and the dynamics of its shockwave. The results are comprehensive in 3 papers printed this week in Nature and Science. (Scientific American is part of Nature Publishing Team.)
A group led by Olga Popova of the Russian Academy of Sciences visited fifty villages surrounding the blast region in the thirty day period soon after the event to communicate to citizens and photograph the damaged home windows and other damage from the meteor. “Typically we’d go into a village and first uncover out in which the local grocery market is, and we’d discuss to the folks powering the counter simply because they’d just listened for the past a few months to what other men and women experienced skilled,” claims study group member Peter Jenniskens of the SETI (Search for Extraterrestrial Intelligence) Institute in Mountain Look at, Calif. “They’d summarize for us, and then we’d go into the streets and chat to individuals. Every person had a tale to notify.” The experts satisfied people who ended up blown off their feet by the meteor’s shockwave, and other people who have been sunburned by ultraviolet light-weight from the fireball. “There was a single man or woman who stated his pores and skin even flaked afterward,” Jenniskens says. The staff discovered that it was often the village educational institutions, which tended to have the largest windows, that suffered the most window injury. The scientists compiled the information from their visits and interviews, as nicely as from an on-line survey of people, to estimate injury and injuries styles around the Chelyabinsk spot.
Each Popova’s crew and a second group, led by Jirí Borovicka of the Academy of Sciences of the Czech Republic and Peter Brown of the College of Western Ontario, utilized online video footage to calculate the meteor’s trajectory. (Popova’s findings have been reported in Science and Borovicka and Brown every led papers published in Character). The scientists frequented the spots exactly where beginner videos experienced been filmed, and photographed the stars in the sky to calibrate the meteor’s precise location and the route it took by means of the ambiance. Both calculations concur well with a trajectory computed from satellite images of the meteor by Colorado Point out College meteorologist Steven Miller and his colleagues, which was published October 21 in Proceedings of the Nationwide Academy of Sciences. “It was great to see that confirmation,” Miller suggests.
Borovicka and Brown’s group discovered that the rock started out about 19 meters extensive, and broke into little items as it descended from 45 to 30 kilometers more than Earth. The meteor’s airburst packed an energy equal to 500 kilotons of TNT, they calculated. The reasonably modest asteroid experienced escaped detection prior to effect, but by computing the meteor’s first velocity and direction of flight, the scientists had been able to deduce the rock’s orbit about the sunlight, which proved to be markedly equivalent to the orbit of a acknowledged, significantly bigger asteroid—a two-kilometer-broad item referred to as 86039 (1999 NC43).