I think judging the size from the object itself is difficult, glare is always a problem for CCTV cameras, especially consumer grade ones, and the glare makes small bright objects look much bigger than they really are.
They tend not to have Wide Dynamic Range either, so light sources and illumination look brighter than they would to the naked eye. Same effect as how a photo taken in a room with a window can make the room look dark and the window a solid white block of light. I'm sure one of our photographers will be able to explain why it happens (related to exposure I believe).
That said I don't think it is small, because if you look at the right of the video a light comes on at about 4 seconds - look at the banister rail, lawn and the lighting and shadow on the sign. It looks to be like a security or courtesy light coming on, probably an IR sensor triggered by the object. As an aside, this is contrary to the text accompanying the video which says there is no other lighting, but likely just an oversight. I think that light, the image becoming lighter once the glare has gone, combined with the CCTV over-emphasising the amount of illumination is probably making it look like the object is illuminating the area more than it actually is.
ETA - of course there is yet another light source, the IR from the camera itself, and IR does make reflective objects look extremely bright. I doubt that's what's causing the object to glow and illuminate the ground though because of the distance and the shadow, unless the shadow was actually a non-reflective area on the object which could explain the erratic movement.
It'd be interesting to try with something reflective, like a foil balloon.
Ray Von
