An asteroid the size of a tour bus zipped by Earth today (June 27) in a flyby so close that the space rock was nearer to the planet than some satellites, giving skywatchers and astronomers a tantalizing target for photos. The space rock, called asteroid 2011 MD, reached its closest point to Earth just after 1 p.m. EDT (1700 GMT), when it crept within 7,500 miles (12,000 km) of Earth before whipping away again like a slingshot. The asteroid was flying over the southern Atlantic Ocean, off the coast...