Bill Cooke of NASA's Meteoroid Environments Office told ABCNews.com the flash was most likely caused by a "boulder-sized space rock" that was a yard in diameter. As the meteor entered the atmosphere over eastern Pennsylvania, it turned into a flying fireball traveling faster than a speeding bullet. Although the flashing lights in the sky were dramatic, Cooke says the meteor is not cause for alarm. "People have no reason to be scared, this is normal activity for this time of year," said Cooke. This is not a portent for an asteroid. Cooke says there are 100 similar incidents every year that happen across the globe. According to the American Meteor Society nearly all meteors burn up between 10 to 20 miles above the Earth's surface.