The meteor exploded on the same day as an asteroid made the closest pass by Earth in recorded history. The events were not connected, and NASA was tracking the asteroid as it passed 17,500 miles away from Earth.
Dr. Bill Cooke, a meteor expert from Marshall Space Flight Center, told a press conference that the Russian meteor approached Earth from the day side and was not picked up by any telescope. "They are almost impossible to see," said Dr. Paul Chodas of NASA's Jet Propulsion Laboratory.
At Marshall today, meteor physicist Dr. Rhiannon Blauuw said NASA is watching meteors capable of causing catastrophic damage to the planet. It will see them years in advance and in time for Earth to plan a response. Defending the planet from smaller asteroids would be much more difficult, scientists said, adding that basketball-sized meteorites hit the Earth every day.
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