A Semi Transparent, White Colored, Luminescent Spherical Cloud circled directly above my home before disappearing entirely.

Shortly after walking outside to smoke a cigarette, I felt like I was being watched, so walked to the rear of my driveway, looked up and noticed a small, slightly illuminated, approximately 5ft wide, spherical cloud floating around 23 to 25ft in the air above the front portion of my backyard. The object appeared to be stationary until observed and briefly spoken to (when I initially spotted the object I said aloud "What are you doing?") At this point, the object slowly (about walking pace) circled above my house, then continued circling around the front of my house, circled above the driveway which I was standing on, circled above the home of the closest neighbor to my left, then back around to the rear my the driveway, then proceeded toward the front of the drive, before vanishing directly above my head. While circling over both house, the lower portion of the object was obscured briefly at the peak of each respective house, which verified my approximate observation of it's height. I walked from center to back, then back to front, then front to back, and then directly under the object as it changed direction east, in order to maintain unbroken observation. To be clear, I have no indication that the object left the area at this point, it simply became invisible to me. It was entirely inaudible, and when stared at directly, no hard lines, shapes, edges or color variations could be observed. I passed my hand through my field of vision while observing the object without any change in it appearance, in order to rule out the possibility of hallucination or optical illusion. This occurred at night, and the weather conditions were cloudy, but my side door has a soft light. No neighbors were present, and no vehicles passed by during the observation. No possibility of abduction, as no time was missing, the object appeared too small to take a person, and no bodily effects were observed during or afterwards.
I am an Air Force Veteran, who served on an active flightline for an overseas long tour at Ramstein Air Base during the height of OEF/OIF as an aerospace ground equipment mechanic. Honorably Discharged. During the observation I was under no impairment, was of calm mind and entirely awake. I made no attempt to photograph or record the object, since it was acting subtly, potentially covertly above my home and those seemed like actions that might be interpreted as hostile.