UFO Sighting in Santa Clarita, California on 2018-04-10 10:10:00 - White object moving in the sky

We were installing solar on a rooftop in santa clarita . coworker was on the ground talking to me while i was on the rooftop. he was away for a while and came back to talk when he sees a white orb in the sky behind my head but he doesn't describe it, he walks up the ladder while his eye is on the object. this whole time i cannot see the object, not until he gets on the roof and stands next to me do i see it. the object varied in altitudes very rabidly split second not only up and down buy moving