Soundless gray sphere near Sacramento International airportI live 7 miles southeast of Sacramento Intl airport and see and hear aircraft constantly.On Wed 10-31-12 at 10:25pm while standing just outside my garage door I noticed a soundless low flying sphere shaped object heading north approx 150 ft up and estimated 500 yds away to the NW of my position on Del Paso Road. There were no lights on it or coming from within, but it appeared gray in color at night. It was moving way faster than a bird could fly.It flew in a straight line north but seemed to bob up and down irregularly. Then suddenly, just before it left my line of sight right above the distant tree line, it vanished for a split second then I saw a brilliant white/yellow flash. What baffled me most was the shape and size of this flash. Its shape looked like a pie slice with hard edges and about 5 times the original size of the sphere.The duration of the event was no longer than 10 seconds. There was a light rain falling and calm winds. Gray.