possible sighting in my back yard.

All right. A few years ago, I had this big trampoline in my back yard. Me and my brother were sleeping out on the trampoline, looking at the sky all of the sudden, this very dim, but noticeable triangular light slowly flew over our heads. it was quite a few miles up, or I would've winded up in a mental institution(no offense to those currently... enrolling in one.) we both noticed it, and we tried to rationalize what it was. It was going too slowly and steadily to be a plastic bag, and it didn't make any noise, so it couldn't be a plane. It was either aa stealth bomber, or some sort of other government experiment.