I was letting the dogs out in the backyard and felt the need to look up. when i did, i witnessed a long sustained single-file line of over 40 objects flying from nw to se. i've never seen this before. there was absolutely no noise. it lasted for over ten minutes. the lights were about three inches (from my view) apart. every seventh object had two lights in a row. i live in the flight path of many airplanes near the airport. i always hear the planes when they fly over even if they aren't landing. no noise and no flashing or running lights. this was very bizarre. i couldn't tell if they all disappeared or just flew out of sight. their speed was constant. never passed each other. i tried to take a pic but don't think it turned out well.