Came out from grocery store and heard what sounded like a jet engine whine... It was after dark out so couldn't see any shape but it was really big, over the store and really low. I just stood there and watched as it passed over the store and then turned/rotated in place and moved away. I looked around at the other people but nobody except for the bagger from Safeway seemed to even notice. It wasn't moving fast, very slow and I couldn't see how it could move that slow and still be in the air. I got in my car, rolled down the window and could still hear the whiney sound. Backed out and could still see something dark moving in the sky but it turned and moved away off to the north.Didn't say a thing to anyone till about a week ago and when I did, my friend said his friend John saw it too but he hadn't believed him until I said I saw something.