I was at work and a boeing 777 flew over on approach to lax when I noticed the orb hovering, I called over some coworkers (7 people) and we watched it for about 2 hours, it was slowly moving to the west. It would move then hover then made some round patterns. It was silver and was emitting a pulsating white light. It was above the planes on approach to lax I would estimate 20,000 ft. then it disappeared. It was to small to register on a picture.