"Shockwaves" was bang on there. I puzzled over these orbs for weeks until I finally saw what was supporting the floating orbs, it was a single strand of spider silk with a few dust or moisture specks fixed to it, slowly swinging in front of the camera lens, the strand was totally invisible until a small change in the lighting made it appear. Sorry to disappoint the extra-terrestial fans or ghost hunters here, but as always, there's a rational explanation for these things. (well, NEARLY always)