A giant space rock the size of a city block (460-feet long and 210-feet wide) whizzed past the planet on Saturday. Asteroid 2013 ET posed little threat, though, as the flyby occurred about 2.5 times the Moon's distance from Earth. Slightly disconcerting is that the asteroid was detected by astronomers only a week ago. If the asteroid had struck Earth, it could have destroyed a small city. More at RT.com.