The year's biggest and best meteor shower is upon us, and NASA officials are urging Americans to flee the city this weekend. The Perseid meteor shower, set to peak from the evening of Sunday through Monday, could produce 50 to 75 shooting stars per hour. But the US space agency warned that if you live in an urban area, light pollution could dim the cosmic show. Skygazers should head outside between 12am and 5:30am to see the meteors streak through a pre-dawn sky. This peak period occurs when there is almost no moon and the sky is especially dark, providing...