The latest one, discovered by the NASA-funded Catalina Sky Survey (CSS) near Tucson, Arizona on Feb. 4., is designated Asteroid 2018 CB. The asteroid, which is estimated to be between 15 and 40 meters in diameter.
Its close approach to Earth came on Friday at around 2:30 p.m. PST (2230 GMT) at a distance of about 64,000 km, which is less than one-fifth the distance of Earth to the Moon.
Known as asteroid 2018 CC, another asteroid also passed closely by Earth on Tuesday at 12:10 p.m. PST (2010 GMT) at a distance of about 184,000 km. The asteroid, which is estimated to be between 15 and 30 meters in size, was also discovered by CSS on Feb. 4.
"Although 2018 CB is quite small, it might well be larger than the asteroid that entered the atmosphere over Chelyabinsk, Russia, almost exactly five years ago, in 2013," Paul Chodas, manager of the Center for Near-Earth Object Studies at NASA's Jet Propulsion Laboratory (JPL), was quoted as saying in a statement. "Asteroids of this size do not often approach this close to our planet -- maybe only once or twice a year."