https://en.wikipedia.org/wiki/Chelyabinsk_meteor The Chelyabinsk meteor was a superbolide that entered Earth's atmosphere over Russia on 15 February 2013 at about 09:20 YEKT (03:20 UTC). It was caused by an approximately 20 m (66 ft) near-Earth asteroid with a speed of 19.16 ± 0.15 kilometres per second (60,000[5]–69,000 km/h or 40,000[5]–42,900 mph).[6][7] It quickly became a brilliant superbolide meteor over the southern Ural region. The light from the meteor was brighter than the Sun, visible up to 100 km (62 mi) away. It was observed over a wide area of the region and in neighbouring republics. Some eyewitnesses also felt intense heat from the fireball. Due to its high velocity and shallow angle of atmospheric entry, the object exploded in an air burst over Chelyabinsk Oblast, at a height of around 29.7 km (18.5 mi; 97,000 ft).[7][8] The explosion generated a bright flash, producing a hot cloud of dust and gas that penetrated to 26.2 km (16.3 mi), and many surviving small fragmentary meteorites, as well as a large shock wave. The bulk of the object's energy was absorbed by the atmosphere, with a total kinetic energy before atmospheric impact estimated from infrasound and seismic measurements to be equivalent to the blast yield of 400–500 kilotons of TNT (about 1.4–1.8 PJ) range – 26 to 33 times as much energy as that released from the atomic bomb detonated at Hiroshima.[9] The object was undetected before its atmospheric entry, in part because its radiant was close to the Sun. Its explosion created panic among local residents, and about 1,500 people were injured seriously enough to seek medical treatment. All of the injuries were due to indirect effects rather than the meteor itself, mainly from broken glass from windows that were blown in when the shock wave arrived, minutes after the superbolide's flash. Some 7,200 buildings in six cities across the region were damaged by the explosion's shock wave, and authorities scrambled to help repair the structures in sub-freezing temperatures. With an estimated initial mass of about 12,000–13,000 tonnes[7][8][10] (13,000–14,000 short tons, heavier than the Eiffel Tower), and measuring about 20 m (66 ft) in diameter, it is the largest known natural object to have entered Earth's atmosphere since the 1908 Tunguska event, which destroyed a wide, remote, forested, and very sparsely populated area of Siberia. The Chelyabinsk meteor is also the only meteor confirmed to have resulted in a large number of injuries. No deaths were reported. The earlier-predicted and well-publicized close approach of a larger asteroid on the same day, the roughly 30 m (98 ft) 367943 Duende, occurred about 16 hours later; the very different orbits of the two objects showed they were unrelated to each other. https://en.wikipedia.org/wiki/Chelyabinsk_meteor#Injuries_and_damage The blast created by the meteor's air burst produced extensive ground damage over an irregular elliptical area around a hundred kilometres wide, and a few tens of kilometres long,[70] with the secondary effects of the blast being the main cause of the considerable number of injuries. Russian authorities stated that 1,491 people sought medical attention in Chelyabinsk Oblast within the first few days.[3] Health officials said 112 people had been hospitalised, with two in serious condition. A 52-year-old woman with a broken spine was flown to Moscow for treatment.[24] Most of the injured were hurt by the secondary blast effects of shattered, falling or blown-in glass.[24][71] The intense light from the meteor, momentarily 30 times brighter than the Sun,[48] also produced injuries, leading to over 180 cases of eye pain, and 70 people subsequently reported temporary flash blindness.[72] Twenty people reported ultraviolet burns similar to sunburn, possibly intensified by the presence of snow on the ground.[72] Vladimir Petrov, when meeting with scientists to assess the damage, reported that he sustained so much sunburn from the meteor that the skin flaked only days later.[73] A fourth-grade teacher in Chelyabinsk, Yulia Karbysheva, was hailed as a hero after saving 44 children from imploding window glass cuts. Despite not knowing the origin of the intense flash of light, Karbysheva thought it prudent to take precautionary measures by ordering her students to stay away from the room's windows and to perform a duck and cover maneuver and then to leave a building. Karbysheva, who remained standing, was seriously lacerated when the blast arrived and window glass severed a tendon in one of her arms and left thigh; none of her students, whom she ordered to hide under their desks, suffered cuts.[74][75] The teacher was taken to a hospital which received 112 people that day. The majority of the patients were suffering from cuts.[75] The collapsed roof over the warehouse section of a zinc factory in Chelyabinsk After the air blast, car alarms went off and mobile phone networks were overloaded with calls.[76] Office buildings in Chelyabinsk were evacuated. Classes for all Chelyabinsk schools were cancelled, mainly due to broken windows.[24] At least 20 children were injured when the windows of a school and kindergarten were blown in at 09:22.[77] Following the event, government officials in Chelyabinsk asked parents to take their children home from schools.[78] Approximately 600 m2 (6,500 sq ft) of a roof at a zinc factory collapsed during the incident.[79] Residents in Chelyabinsk whose windows were smashed quickly sought to cover the openings with anything available, to protect themselves against temperatures of −15 °C (5 °F).[80] Approximately 100,000 home-owners were affected, according to Chelyabinsk Oblast Governor Mikhail Yurevich.[81] He also said that preserving the water pipes of the city's district heating was the primary goal of the authorities as they scrambled to contain further post-explosion damage.[24] By 5 March 2013 the number of damaged buildings was tallied at over 7,200, which included some 6,040 apartment blocks, 293 medical facilities, 718 schools and universities, 100 cultural organizations, and 43 sport facilities, of which only about 1.5% had not yet been repaired.[4] The oblast governor estimated the damage to buildings at more than 1 billion rubles[82] (approximately US$33 million). Chelyabinsk authorities said that broken windows of apartment homes, but not the glazing of enclosed balconies, would be replaced at the state's expense.[83] One of the buildings damaged in the blast was the Traktor Sport Palace, home arena of Traktor Chelyabinsk of the Kontinental Hockey League (KHL). The arena was closed for inspection, affecting various scheduled events, and possibly the postseason of the KHL.[84] The irregular elliptical disk shape/"spread-eagled butterfly"[85] ground blast damage area, produced by the airburst,[86] is a phenomenon first noticed upon studying the other larger airburst event: Tunguska.[87]