I stepped out of my house to smoke and caught a white flash out of the edge of my eye almost above my trailer so I looked up and I saw a white glowing object, it was very high but not as high as commercial airliners fly, I could not tell a shape but it was as big as a commercial airliner or bigger. It was moving north about the speed as a airliner but there were no flashing lights just a white glow, it flew north for a couple minutes across the valley then when it was over the north rim of our valley it did a u turn not a 90* but too sharp of a turn for an airplane.Then it excellerated and flew south east and flew from one side of the valley to the other aprox. 35 to 50 miles in three seconds and was out of site. It appeared as fast as a falling star as it flashed across the sky.I don't know what it was but I have seen military jets fly across our valley and know this was no conventional jet, it had no flashing lights and I have never seen something go any where near as fast as this thing flew from one side of our valley to the other.I would estimate it was above 10000 feet maybe higher when I saw it right above my home, but it only flashed white one time that is what drew my attention. I see commercial airliners all the time and know their speed and flashing lights...It was very exciting cause I know it was not an airplane of any type, what it was I don't know.