99942 Apophis (provisional designation 2004 MN4) is a near-Earth asteroid and a potentially hazardous object, 450 metres (1,480 ft) by 170 metres (560 ft) in size. During a brief period of concern in December 2004, initial observations indicated a probability of 0.027 (2.7%) that the asteroid would hit or pass Earth on Friday, April 13, 2029.
