A newly discovered small asteroid has harmlessly zipped close to Earth — just as scientists expected. The 16-foot-long space rock, discovered on Memorial Day, passed by early Tuesday at a distance of 8,950 miles from the Earth\'s surface. NASA\'s Jet Propulsion Laboratory, which tracks such flybys, said the asteroid — dubbed 2012 KT42 — was the sixth closest asteroid approach. It was the second asteroid encounter this week. On Monday, another asteroid, measuring 69 feet across, flew by at a distance of 32,000 miles.