Saw roating round globe moving low above our treeline rotating white to black.

While sitting on our patio watching birds coming in to roost as the sun was just below the horizon, we both noticed a round object flying from left to right above our treeline about a mile out (max) and perhaps 1,000 to 2,000 foot altitude. Due to the white color I assumed it was just an aircraft reflecting the setting sun making it appear white. I then realized I could actually watch the while smoothly become black, then white in a steady transition. The darkness was rotating from the left as would the white during the light dark light transitions of the object.
By the time I realized this was unlike anything I had seen before, it was too late to grab a camera as it moved behind my treeline as It moved along .
Background on me, I served in the US Army Infantry airborne for 12 years. I work on a Airforce based, and have a clearance. Ice seen plenty of things in my time, I am 62. I doubt we have this type of technology. No sound at all. We have a bombing range nearby and only F16's here. No jet looks like this. I would describe this as a ball that is light and dark which slowly rotates whileovi g smoothly and not terrible fast.