You probably never noticed it, but an asteroid slipped by the Earth between us and the moon's orbit at about 3:51 AM PT on September 8, and a second asteroid will be making a flyby later on, at around 3 PM Pacific Time.  The first and larger space rock, named 2010 RX 30, is about 33 to 65 feet wide and slid by at a distance of 154,000 miles away.  The second one, 2010 RF 12, is estimated at between 20 and 46 feet in diameter and will pass at about 49,000 miles from Earth, which in cosmic terms means both are "near miss".  It should be noted that an asteroid that size is believed to have created Arizona's Meteor Crater.