Upon further review, a big scary-sounding asteroid is no longer even a remote threat to smash into Earth in about 20 years, NASA says. Astronomers got a much better look at the asteroid when it whizzed by Earth on Wednesday from a relative safe 9 million miles away. They recalculated the space rock's trajectory and determined it wasn't on a path to hit Earth on April 13, 2036 as once feared possible. At more than 1,060 feet wide, the rock called Apophis could do significant damage to a local area if it hit and perhaps even cause a tsunami. But it was not large enough to trigger worldwide extinctions. One prominent theory that explains the extinctions of dinosaurs and other species 65 million years ago says a six-mile-wide meteorite hit Earth and spewed vast amounts of dust into the air, cooling and darkening the planet. Read more http://abcnews.go.com/Technology/wireStory/whew-big-asteroid-longer-threat-earth-18184546
