bright object up above plane traveling in a nw direction round and flat looking. object just disappeared into thin air. sky was very clear, no clouds whatsoever in the sky. watched if for 3 minutes before it just vanished. the object decreased in size before disappearing. i had just got off from work at 4:pm and began riding on my bike in residential neghborood heading east when i looked up at a plane flying low and noticed a strange shaped object in the sky heading north west. moving slowly.could not identify it to any conventional known craft. i was extremely curious and felt odd that i would have to stop riding to get a better look at this thing. it suddenly began to shrink in size and just vanished.