Sphere hovering in the sky near fighter jet.While mowing my grass, I noticed the sound of a loud jet engine. I looked up and noticed a fighter jet flying over and circling my neighborhood at a low altitude. I ran in the house to get my phone to take a picture of the fighter jet. Upon returning to my front yard, I looked off into the distance to locate the fighter jet. At that time, I noticed a round object hovering off in the distance, near the fighter jet, at a very high altitude. It was visible to my naked eye, but when I zoomed in to take a picture of the object, it would not show up on my camera. I continued to watch it hover for about 30 seconds, with no apparent sound. The sphere then darted to the right, made an immediate stop, and hovered for about 5 seconds, before it darted back to the left the same distance and continued to hover. At this time, the fighter jet was not visible and had disappeared off in the distance. After hovering for another 5 seconds, motionless, the sphere took off across the sky at an incredible speed, covering a great distance in a very short period of time, and disappeared beyond the tree line of my back yard.