Several dozen asteroids ranging in size from 6-12 meters or 20 - 39 feet are known to fly by Earth at a distance closer than the Moon each year, but few are detected and fewer yet are charted before they arrive. An increasing number of sky surveys by both professional and amateur astronomers, however, is detecting smaller and more distant asteroids.

Asteroid 2024 YA5, a piece of rock the size of a bus some 31 feet long, passes by Earth at a distance of no less than 218,000 miles on December 29, according to the Jet Propulsion Laboratory’s Asteroid Watch.

The last asteroid impact on Earth occurred over Russia in 2013 when a 17-meter chunk of space rock exploded mid-air. The most significant asteroid in recorded history, however, was the 1908 Tunguska event in Siberia that produced a 12-megaton explosion.