"Upcoming Close Encounters: 5 Massive Asteroids to Pass Near Earth, Including Stadium-Sized One"

Five asteroids, including one the size of a sports stadium, are expected to pass within less than 2 million miles of Earth this week, with the largest, asteroid 2008 OS7, coming closest at 1.77 million miles. While there is no risk of impact, NASA's Asteroid Watch website is tracking these near-misses. The asteroids range in size from "building-size" to "airplane-size," and NASA defines potentially hazardous objects as those larger than 500 feet and predicted to come within 4.7 million miles of Earth.