Shimmering egg shaped object heading north over CA.Egg shaped object heading north at 11:55am. I was at work noticing how the moon was still visible in the middle of the day, when a flash of light in the sky caught my eye. Then it flashed again, and I saw a shimmering ball to egg shaped object moving north holding an extremely constant heading, altitude, and speed. There was no sound or contrails. I thought it might have been a mylar baloon, but it was odd that when it was'nt reflecting light, it was black. IF you put a silver baloon against a blue sky, it will apear white. I know because I worked in the Air Force as a weather observer, and rawinsaunde operator. I am also an instrument rated pilot. Since the object had no wings or protrusions, it was impossible to reference it's size, altitude, or speed. If it was a baloon, it could'nt have been more than 500 feet high AGL, traveling at 100 kts. (the upper air winds were out of the south, but only 15kts.) After the object went out of view, I stared at the sky for a couple of minutes, then started to go back to work when I heard the sound of a jet engine out of the southeast. I spotted the jet, and could make out the delta wing. It was up around 30,000 feet flying a wide S patern coming up behind whe object's path screaming at well over mach 1. If the object was at 30,000 feet, I would estimate it to be the size of the space shuttle with a ground speed of over mach 2.