“This was roughly the equivalent of spotting something the size of a gnat from a distance of 310 miles (500 kilometres).”
Davide Farnocchia, a scientist at NASA’s Center for Near Earth Object (NEO) Studies, said: “Asteroids this size are far smaller than what we’re tasked to track.
“They’re so small, they would not survive passing through our atmosphere to cause damage to Earth’s surface.”
The problem was, NASA said, the space agency could not determine where the space rock was heading.
NASA said: “The body had been spotted only four times in just under half an hour, which was not enough information to determine where the object came from or exactly where it was headed.”
Just last month, the European Space Agency (ESA) said it too missed an NEO recently, calling for better asteroid watch.
On July 25, a huge asteroid which was roughly the size of a football pitch, skimmed Earth, and scientists were unaware it was coming.