Largest-ever asteroid is about to fly by Earth

Near-Earth objects make passes by our planet on a fairly regular basis, but the space rock that's going to cruise by on September 1st is a real goliath. Named Florence, the massive asteroid is thought to be the largest object to make such a close approach to Earth since NASA decided to start keeping records for that sort of thing. The good news is that scientists don't believe it poses much of a threat — at least this time around.While many near-Earth asteroids that safely pass our planet