 And scientists are saying not to worry about two giant asteroids hurtling toward Earth. The European Space Agency says an asteroid over a mile wide will be zipping by the Earth this afternoon at a relatively close 4 million miles away, posing no threat. They say it's the closest flyby on record of an asteroid that large. And Saturday, another huge asteroid will zip past. A recently discovered asteroid smaller, about 800 feet wide, but will be closer at 180,000 miles from Earth. Scientists can say there's no risk of hitting us.