As most asteroids passing within a lunar distance are less than 40 meters in diameter, they generally are not detected until they are within several million km of Earth.
As most asteroids passing within a lunar distance are less than 40 meters in diameter, they generally are not detected until they are within several million km of Earth. (en)
As most asteroids passing within a lunar distance are less than 40 meters in diameter, they generally are not detected until they are within several million km of Earth. (en)