I was driving on a street in green valley, az. i noticed a silvery white object in the sky to the north east (i was headed in that direction. i observed it for about 30 seconds, it appeared to be stationary from my perspective. i first thought it could be an airplane traveling away from me, but it wasn't diminishing in size, then i thought it might be a helicopter, but it didn't really look like the right shape. the closest thing it resembled would possibly be a model drone, in which case it would have been much closer than it appeared to be. my estimation would be that the object was 10-20 miles away. the main reason i think this object may have been a real ufo was because it literally vanished into thin air as i was watching it. it was clearly visible one second, then completely gone the next. i am a skeptic, but i couldn't identify the object, it was clearly flying, or hovering in the sky, and it vanished in a clear blue sky. i'm reporting this event, just in case anyone else might have observed this object, unfortunately, i have no video or pictures. hopefully someone else might have seen it.