Luminous rectangle, no lights or sound, tremendous speed.While star-gazing in the backyard on a clear night, movement caught my eye to the right (south), which I first thought was a streaking meteor (because of the spead, size, and low luminosity). I think it was moving at a 45 deg angle downward, and then began (on a dime) to move in a line parallel to the earth, and directly in my direction (northward). The speed probably about that of a fighter jet with afterburners going (based on past observations of those). Object was a self-luminous body, grey-blue-white, not very bright, about like the moon behind thick clouds, and was retangular, with no lights whatsoever. No sound at all. The backyard is quiet, and it flew directly overhead. It was about twice as long as wide (2:1), and took, I guess, between 8 and 11 seconds to traverse from 30 deg above my right horizon (about 800 - 1200 feet high?) to my left horizon and disappear. There was no wind at all. This was not a bird or balloon. It was hauling straight line, overhead. I was very careful to make mental notes as I observed, trying to see any extensions beyond the rectangular shape, but could not see anything more. Honestly, it did appear to change its shape after it passed overhead and was halfway between me, and the point on the horizon where it disappeard... into almost a birdlike shape for an instance, and then changed back, then disappear. The size was a one inch object held 12 inches from your eyes.