Since yesterday, many experts!! have had claims that it was too small and fast to track and intercept the meteor hit Chelyabinsk the city in Russia hosts greatest Russian nuclear facilities.
Well let us look a bit American sources about other impacts before. Here you are an example below:
http://blogs.scientificamerican.com/observations/2012/12/20/california-meteor-broke-speed-record-for-atmospheric-entry/
Keep on reading the details.
Meteor astronomer Peter Jenniskens must move quickly to trap evidence of a fresh meteorite fall. In 2008, a small asteroid roughly three meters across struck Earth’s atmosphere over northern Sudan, producing a brilliant fireball in the sky. The asteroid’s orbit had been tracked before striking Earth, upping the chances that searchers would be able to locate pieces of the meteorite on the ground. So Jenniskens traveled to the Nubian Desert to recover fragments, as did dozens of searchers from the University of Khartoum.
In April of this year, he did not have to travel nearly so far to gather fresh meteoritic material. A bright fireball lit up the daytime sky April 22 over northern California’s gold country, a few hours’ drive from Jenniskens’s bases of operations in the San Francisco Bay Area: the SETI Institute in Mountain View and the NASA Ames Research Center in Moffett Field. The California bolide, like its African predecessor, made a well-documented entry—three Doppler radar stations picked up the track of the fireball, pointing the way to meteorite fragments on the ground. (The asteroid itself had not been spotted in space—such small objects usually escape astronomers’ notice.) Given the convenient location, the searchers were even able to marshal a slow-moving zeppelin to scan the area from the air, to look for impact scars on the terrain below caused by large meteorite fragments, but none were found.
Jenniskens and other searchers did ultimately locate 77 smaller pieces of the meteorite on the ground, according to a study he and his colleagues published in Science on December 21.
Drawing on witnesses’ photos and videos of the fireball, the researchers have calculated that the parent object of the Sutter’s Mill meteorite entered the atmosphere at 28.6 kilometers per second (64,000 mph)—the highest such entry velocity recorded for recovered meteorites.
So the claims of those experts about speed of Chelyabinsk meteor prevented to be tracked remain invalid by this events. Even smaller eighter faster objects could be tracked according to this source.
And this is from NASA's official web site:
http://www.nasa.gov/mission_pages/asteroids/news/asteroid20130214.html
Like trailers for the coming attraction, new images show asteroid 2012 DA14 on its way to a record-close approach to Earth on Feb. 15. One image, taken by amateur astronomer Dave Herald of Murrumbateman, Australia, on Feb. 13, shows the asteroid as a tiny white dot in the field of view. Another set of animated images, obtained by the Faulkes Telescope South in Siding Springs, Australia, on Feb. 14, and animated by the Remanzacco Observatory in Italy, shows the asteroid as a bright spot moving across the night sky.
These are some of many images that may be taken of the asteroid during its close - but safe - encounter with Earth. It will be observed by numerous optical observatories worldwide in an attempt to determine its rough shape, spin rate and composition. NASA scientists will use NASA's Goldstone Solar System Radar, located in California's Mojave Desert, to take radar images of the asteroid to determine its precise size and shape on Feb. 16, 18, 19 and 20. The NASA Near Earth Object Observation (NEOO) Program will continue to track the asteroid and predict its future orbit.
Asteroid 2012 DA14 is about 150 feet (45 meters) in diameter. It is expected to fly about 17,200 miles (27,000 kilometers) above Earth's surface at the time of closest approach, which is about 11:25 a.m. PST (2:25 p.m. EST) on Feb. 15. This distance is well away from Earth and the swarm of low Earth-orbiting satellites, including the International Space Station, but it is inside the belt of satellites in geostationary orbit (about 22,200 miles, or 35,800 kilometers, above Earth's surface.) The flyby of 2012 DA14 is the closest-ever predicted approach to Earth for an object this large.
The NASA Near Earth Object Observation (NEOO) Program detects and tracks asteroids and comets passing close to Earth using ground- and space-based telescopes. The network of projects supported by this program, commonly called "Spaceguard," discovers these objects, characterizes a subset of them and plots their orbits to determine if any could be potentially hazardous to our planet.
And other example from NASA:
http://www.jpl.nasa.gov/news/news.php?release=2013-017
Russian tracking and early warning systems may be insufficent and unfunctional for such threats but it s clear NASA is enable to do it even 23 years before the close flyby. Chelyabinsk residents were unlucky NASA could not detect the meteor this time. Otherwise I am sure they would make a friendly warning to Russian authorities to avoid 1000 people to be injured.
Well let us look a bit American sources about other impacts before. Here you are an example below:
http://blogs.scientificamerican.com/observations/2012/12/20/california-meteor-broke-speed-record-for-atmospheric-entry/
California Meteor Broke Speed Record for Atmospheric Entry
December 20, 2012| 
10
10Keep on reading the details.
Meteor astronomer Peter Jenniskens must move quickly to trap evidence of a fresh meteorite fall. In 2008, a small asteroid roughly three meters across struck Earth’s atmosphere over northern Sudan, producing a brilliant fireball in the sky. The asteroid’s orbit had been tracked before striking Earth, upping the chances that searchers would be able to locate pieces of the meteorite on the ground. So Jenniskens traveled to the Nubian Desert to recover fragments, as did dozens of searchers from the University of Khartoum.
In April of this year, he did not have to travel nearly so far to gather fresh meteoritic material. A bright fireball lit up the daytime sky April 22 over northern California’s gold country, a few hours’ drive from Jenniskens’s bases of operations in the San Francisco Bay Area: the SETI Institute in Mountain View and the NASA Ames Research Center in Moffett Field. The California bolide, like its African predecessor, made a well-documented entry—three Doppler radar stations picked up the track of the fireball, pointing the way to meteorite fragments on the ground. (The asteroid itself had not been spotted in space—such small objects usually escape astronomers’ notice.) Given the convenient location, the searchers were even able to marshal a slow-moving zeppelin to scan the area from the air, to look for impact scars on the terrain below caused by large meteorite fragments, but none were found.
Jenniskens and other searchers did ultimately locate 77 smaller pieces of the meteorite on the ground, according to a study he and his colleagues published in Science on December 21.
Drawing on witnesses’ photos and videos of the fireball, the researchers have calculated that the parent object of the Sutter’s Mill meteorite entered the atmosphere at 28.6 kilometers per second (64,000 mph)—the highest such entry velocity recorded for recovered meteorites.
So the claims of those experts about speed of Chelyabinsk meteor prevented to be tracked remain invalid by this events. Even smaller eighter faster objects could be tracked according to this source.
And this is from NASA's official web site:
http://www.nasa.gov/mission_pages/asteroids/news/asteroid20130214.html
Like trailers for the coming attraction, new images show asteroid 2012 DA14 on its way to a record-close approach to Earth on Feb. 15. One image, taken by amateur astronomer Dave Herald of Murrumbateman, Australia, on Feb. 13, shows the asteroid as a tiny white dot in the field of view. Another set of animated images, obtained by the Faulkes Telescope South in Siding Springs, Australia, on Feb. 14, and animated by the Remanzacco Observatory in Italy, shows the asteroid as a bright spot moving across the night sky.
These are some of many images that may be taken of the asteroid during its close - but safe - encounter with Earth. It will be observed by numerous optical observatories worldwide in an attempt to determine its rough shape, spin rate and composition. NASA scientists will use NASA's Goldstone Solar System Radar, located in California's Mojave Desert, to take radar images of the asteroid to determine its precise size and shape on Feb. 16, 18, 19 and 20. The NASA Near Earth Object Observation (NEOO) Program will continue to track the asteroid and predict its future orbit.
Asteroid 2012 DA14 is about 150 feet (45 meters) in diameter. It is expected to fly about 17,200 miles (27,000 kilometers) above Earth's surface at the time of closest approach, which is about 11:25 a.m. PST (2:25 p.m. EST) on Feb. 15. This distance is well away from Earth and the swarm of low Earth-orbiting satellites, including the International Space Station, but it is inside the belt of satellites in geostationary orbit (about 22,200 miles, or 35,800 kilometers, above Earth's surface.) The flyby of 2012 DA14 is the closest-ever predicted approach to Earth for an object this large.
The NASA Near Earth Object Observation (NEOO) Program detects and tracks asteroids and comets passing close to Earth using ground- and space-based telescopes. The network of projects supported by this program, commonly called "Spaceguard," discovers these objects, characterizes a subset of them and plots their orbits to determine if any could be potentially hazardous to our planet.
And other example from NASA:
http://www.jpl.nasa.gov/news/news.php?release=2013-017
January 10, 2013
PASADENA, Calif. -- NASA scientists at the agency's Jet Propulsion Laboratory in Pasadena, Calif., effectively have ruled out the possibility the asteroid Apophis will impact Earth during a close flyby in 2036. The scientists used updated information obtained by NASA-supported telescopes in 2011 and 2012, as well as new data from the time leading up to Apophis' distant Earth flyby yesterday (Jan. 9).Russian tracking and early warning systems may be insufficent and unfunctional for such threats but it s clear NASA is enable to do it even 23 years before the close flyby. Chelyabinsk residents were unlucky NASA could not detect the meteor this time. Otherwise I am sure they would make a friendly warning to Russian authorities to avoid 1000 people to be injured.
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