On Saturday March 9th, 2013, at approximately 3:30 p.m. EST, an asteroid the size of a city block flew 37,282 miles from Earth at 26,000 miles per hour.  Unlike other asteroids in recent news, however, Asteroid 2013 ET was not discovered until six days prior to its passing.  It was the first in a series of asteroids passing near Earth throughout the weekend.  Asteroid 2013 EC 20 followed later Saturday, and Asteroid EN 20 is expected to pass sometime Sunday.  As with Asteroid 2013 ET, the latter two were identified just days before their passing.