Coincidence or related?
According to Nature a Canadian astronomer agrees with ESA's conclusions
"It was a very, very powerful event," says Margaret Campbell-Brown, an astronomer at the University of Western Ontario in London, Canada, who has studied data from two infrasound stations near the impact site. Her calculations show that the meteoroid was approximately 15 metres across when it entered the atmosphere, and put its mass at around 7,000 metric tonnes. "That would make it the biggest object recorded to hit the Earth since Tunguska," she says.
The European Space Agency does not think that the meteor is related to a much larger asteroid known as 2012 DA14, which will be passing within about 20,000 kilometres of Earth later today. Both the timing of the meteor's appearance and its location indicate that it came from a different direction, Klinkrad says. Campbell-Brown agrees: "We happened to have close approaches to two of them, and one of them got us," she says.
NASA agree with the ESA
Editor's Note: NASA statement on Russia meteor:
"According to NASA scientists, the trajectory of the Russia meteor was significantly different than the trajectory of the asteroid 2012 DA14, making it a completely unrelated object. Information is still being collected about the Russia meteor and analysis is preliminary at this point. In videos of the meteor, it is seen to pass from left to right in front of the rising sun, which means it was traveling from north to south. Asteroid DA14's trajectory is in the opposite direction, from south to north."
What is a meteor?
A small body of matter from outer space that enters the earth's atmosphere, appearing as a streak of light.
How common are meteors?
The Chelyabinsk meteor was the largest for 104 years, but meteors in general are commonplace.
The International Meteor Organisation says
The VMDB contains about 3,000,000 meteors obtained by standardized observing methods which were collected during the last ~25 years.