Low flying craft that defies explanation.

As I drove down Chalfont Drive I noticed a silver object moving at a slow, steady pace.  It was 8 pm but still quite light out as this was in summer.  It was heading north and I decided to follow it.  As I made a left onto Waldermire Drive I followed the craft as far as I could.  The object was round and metallic (I could see sun light reflection).  As I made this turn I caught a quick glimpse of the rear view of the object.  It had two half circles with a rod connecting these two half circles.  So in other words this object had two half round sides with something connecting them in between.  The side view showed a round metallic shere.  The rear showed two half spheres.  As I made the left turn onto Wlademire Drive there were a man and woman at their parked car and she was pointing at this object.  I kept driving to follow it.  I did eventually lose sight of it as there was no way to follow because of the direction it was traveling and the road did not go that way.  It was flying low.