String formation of five reddish lights flew south over DC area on a clear, cold December night (11PM); too fast to be aircraft.Outside with dog at 11PM. Facing south/southeast, looked up at the stars. A clear cold night... saw Orion's belt and my gaze was drifting toward zenith when, at appox 10 degrees south of zenith i noticed a "string" of dim, starlike, warm-color, (reddish) points of light passing overhead from zenith heading due south. The "string" was approx 1.5x to 2x diameter of full moon, marked by almost equal intervals between the lights. The lights traveled in a straight line toward the south (there was a bit of very slight variation in the formation - they were not following the leader with exact precision - the spacing between them varied slightly and there was also some very slight variation side-to-side as they moved south. This gave me the feeling that the lights were each separate entities and not part of the same rigid body (but they could have been part of a non-rigid body, like a string, for example). The lights were each only about half as bright as Betelgeuse and definitely much smaller than Betelgeuse... I might not have noticed if there was only one of them... it was the formation that caught my eye. I followed them for about 5 seconds as they covered approx 35-40 degrees of sky before they faded into the southern sky. They appeared to be in the atmosphere (not in space) - high up, at the altitude of high altitude jetliners or military patrols, but not as high as satellites (the brightness varied a little for each one through time as if they were passing thru mists -- yet, as I said, it was a clear cold night). There appeared to be a very dim glowing blur between the objects.