I saw a round, red-orange colored sphere flying horizontal to the ground, emitting no noise. i tracked it for 15-20 seconds. it seemed higher than most personal aircraft in this area, yet lower than commercial aircraft that are not that high as they approach smf (sacramento intl). the flight path is perpindicular to most aircraft in the area (both commercial and private). at first i thought it was a personal aircraft on fire, and fully expected it to fall from the sky. yet it maintained a steady altitude and direction. there were no blinking or steady lights, just a the round sphere like shape. i was distracted after watching for approximately 15 seconds by my daughter's dog, and two different neighbors asking "what are those things?". apparently, they saw 3-4 more of them, separated by 10-15 seconds. i only saw the one, and never saw any more. no clue what it was, i have about 10 seconds of video on my phone. i don't believe in typical ufos, aliens, etc... but certainly have no idea what this could be. it does not seem like it could be a drone to me either.