Orb?

by Garry Steele
(Edinburgh, UK)

We had this photo taken although we didnt know what or if it is an orb. It was roughly 9 pm and being bored we took lots of pictures but this was the only one that seems to have an orb.

We have pictures of loved ones who have passed away just behind where the photo was taken.
Has anyone got any ideas why out of about 50-60 photos an "orb" only appears in one.

mr and mrs steele edinburgh uk.