...Last night (Sunday, October 5th), a telescope on Mount Lemmon, Arizona, detected a tiny moving blip, the signature of a small chunk of rock moving rapidly through space. Twenty-five observations have been done since then by professional and amateur astronomers around the world, and the object's orbit has been pinned down with fairly high precision. It is almost certain to hit Earth's atmosphere around 10:46 p.m. EDT tonight, October 6th. (That's 2:46 a.m. October 7th, Greenwich Mean Time.) The rock is roughly 10 feet (3 meters) across, and it's expected to enter the atmosphere above northern Sudan at about 8...