Bus-sized asteroid to pass Earth closely

An asteroid at least the size of a city bus will make an extremely close pass by Earth but poses no threat to the planet, U.S. astronomers say. NASA officials say Asteroid 2011 MD will make its closest approach at 1:14 p.m. EDT Monday and will pass just over 7,500 miles above Earth's surface, SPACE.com reported Friday. The asteroid will over Earth high above Antarctica, almost 2,000 miles south-southwest of South Africa. The asteroid, estimated at somewhere between 29 and 98 feet wide, was discovered Wednesday by telescopes in New Mexico that routinely search the heavens for near-Earth asteroids. "There is no chance that 2011 MD will hit Earth but scientists will use the close pass as opportunity to study it with radar observations," astronomers with NASA's Asteroid Watch program at JPL wrote in a Twitter post. Even if it entered Earth's atmosphere it probably wouldn't reach the ground, they wrote. "Asteroid 2011 MD measures about 10 meters. Stony asteroids less than 25 m would break up in Earth's atmosphere & not cause ground damage," Asteroid Watch scientists wrote. An object of this size will come this close to Earth about every six years or so, the Near-Earth Object Office at NASA's Jet Propulsion Laboratory in Pasadena, Calif., said.