I am invisible, weigh nothing, and if you put me in a barrel, it will become lighter. what am i? i am always there, some distance away, somewhere between land and sky i lay, you may move toward me, yet distant i'll stay. what am i? what has four fingers and a thumb, but is not made of flesh, fish, bone, or fowl? the man who made it doesn't want it. the man who bought it doesn't need it. the man who needs it doesn't know it. what is it? what can go around the world, yet stays in a corner?