On the morning of Friday, 2013 February 15, a bright meteor (also known as a fireball or bolide) entered the earth's atmosphere over central Asia, moving from southeast to northwest and terminating near the Russian city of Chelyabinsk (which is located about a thousand kilometers due east of Moscow, just north of central Kazakhstan). The bright fireball was about the apparent brightness of the sun as seen in the dawn shortly before sunrise at Chelyabinsk, Russia, where the ensuing shock wave from the airblast (caused by the large meteroid entering the earth's atmosphere at around 40000 mph, or 14-17 kilometers per second) caused damage to buildings and injury to some 1200 people around Chelyabinsk -- mostly from broken windows/glass.
The event made instant worldwide headline news and put focus back on the fact that such impacts at earth from natural objects orbiting the sun are a continuing occurrence -- enhanced by the odd coincidence of the predicted, and highly publicized, very close predicted pass of the minor planet 2012 DA14 (diagram here by Syuichi Nakano) only a half-day later (though the two objects are unrelated). Such airblast events capable of causing damage occur probably on the order of once every 10-20 years or so, though damage caused by actual meteorites themselves impacting cars, building, and even animals and people, are much more common (see the link below to interesting past meteorite falls). At least three seismic-monitoring stations in Kazakhstan recorded earth tremors from the airblast; the U.S. Geological Survey has made these available online.
The first published pre-impact orbital information for the Chelyabinsk meteoroid was published by the Central Bureau for Astronomical Telegrams on CBET 3423 (available here).
There are some early reports of small pieces of meteorites from this fall, but nothing very large; a February 25 Russian news article on apparent meteorites found from the event is posted here.
Diagram of Chelyabinsk meteoroid impact by Syuichi Nakano (Sumoto, Japan). The actual path is represented by the lower gold/yellow line with an arrow underneath; the red shading is provided to show the three-dimensional aspect to indicate the meteroid's location above the earth as it approached impact. The times given are in Universal Time (UT), the time used for practical purposes in astronomy (which is essentially Greenwich Mean Time). Nakano assumed a collision time of 2013 Feb. 15d03h20m26s UT occurring at geographical longitude 60.5 deg east, latitude = +55.5 deg, with the apparent radiant point and velocity from CBET 3423. He then performed differential correcting to yield values R.A. = 334.6113 deg, Decl. = -0.7289 deg, and velocity 13.8298 km/s for the geocentric radiant. Nakano's computed orbital elements used for the diagrams are as follows:
T 2012 Dec. 31.04786 TT Nakano q 0.7606967 (2000.0) P Q n 0.47695852 Peri. 109.70844 +0.23846945 -0.97043198 a 1.6223665 Node 326.42524 +0.86381956 +0.22952631 e 0.5311191 Incl. 3.87128 +0.44378834 +0.07469566 P 2.07 H = 26.5
Pre-impact heliocentric orbit diagram of Chelyabinsk meteoroid, also by Syuichi Nakano; note that the sun is at the center with the orbits of Mercury, Venus, Earth, and Mars shown with respect to that of the meteroid about the sun prior to Earth-impact on 2013 Feb. 15. The shaded part of the meteroid's orbit represents that above the orbital plane of the solar system (the major planets orbit the sun in nearly-circular elliptical paths around the sun that are of similar inclination with respect to the earth's orbit, where as the meteroid had a more highly elliptical orbit that departed much more from that of a circular shape, and its orbit was slightly more highly inclined with respect to that of the earth's orbit). The point labelled q is the perihelion distance (i.e., when closest to the sun) of the meteoroid; the ascending and descending nodes (capital letter Omega and upside-down letter Omega, respectively) are where the meteoroid's orbit crossed the plane of the earth's orbit -- note that the impact occurred at the descending node).
Contact for more information: cbatiau (at) eps.harvard.edu
Some of the more interesting videos posted online of the Chelyabinsk fireball and the aftermath (including sonic boom from the airblast and resulting damage to windows and buildings) can be accessed via these website links: Link 1 * Link 2 * Link 3 * Link 4 * Link 5