While walking with my wife at 9:15 pm in brambleton va off northstar blvd and emerald chase plaza. viewed an small star sized white object moving across the sky towards the south at a constant speed until at one point disappeared suddently. ( no clouds in the sky ). we then observed across the sky coming from the north a string of these similar lights evently spaced and traveling at the same constant speed. we counted at least 40 over a 20 minute period. all moved to the exact same location as the first in the sky and just disappered. this string of objects strecked for miles across the sky. this was an especially dark night sky with no cloud coverage. my wife is a flight attendant and at first we thought they might be planes following a flight pattern into dulles airport but after observing definetely not the case. especially the fact they all disappered at the same point in sky above us. the line of lights moved from the north arcoss the sky to the south in a flat trajectory before slightly moving up to the same point of disapperaing. at least two other objects came from another location to this point and disappered. my wife and i have lived in this area for ten years and are very familar with airflight traffic in this area to dulles internation and other surrounding airports. first time we've seen anything like this.