We believe that Orbs are balls of energy, not an actual ghost.   Some people think that it is just dust or air-born particals.  Being a house wife i know how dust moves and this is not the case.  If it were dust there would be many of them and moving all in one direction as the wind would blow them. 

We also believe that the really bright pin points of light is energy as well.  I do think that a ghost could use these energys to help manifest form or sound.