Near-Earth asteroids (NEAs) are space rocks that get within 50 million kilometers of Earth’s orbit. This animation charts their graph from 1999 till January 2018. A 427-foot-wide asteroid named 2019 OK came within 45,000 miles of the Earth on July 29. 45,000 miles is only 20% of the distance between the Earth and the moon. In that sense, 2019 OK was actually quite a narrow miss. Scientists believe that more than half of the large asteroids are not spotted.