"We would expect an event of this magnitude to occur once every 100 years on average," said Paul Chodas of NASA's Near-Earth Object Program Office at the Jet Propulsion Laboratory in California.
"When you have a fireball of this size, we would expect a large number of meteorites to reach the surface, and in this case there were probably some large ones."
In what astronomers said was an unrelated coincidence, a larger asteroid, called 2012 DA14, passed relatively close to Earth around 2:24 p.m. ET Friday.
Stargazers in Australia, Asia and Eastern Europe could see the asteroid with the aid of a telescope or binoculars, but it never got closer than 17,100 miles to the planet's surface.
The Russian meteor was about one-third the size of the asteroid. The two bodies were on very different trajectories, scientists said.