An asteroid at least the size of a 60-story building will make a distant flyby of Earth this week, and you watch astronomers track the space rock tonight (March 9) in a live webcast, weather permitting. The asteroid poses no threat to Earth. The online Slooh community observatory will host the free webcast at 10 p.m. EDT (0200 GMT) to track asteroid 2014 CU13, a space rock about 623 feet (190 meters) wide discovered on Feb. 11 that will pass Earth at a range of about eight times the distance between Earth and the moon on Tuesday (March 11). The...