Orbs are the most common type of photographic evidence to support the existence of ghosts. They are either blue or white translucent balls of light that appear hovering over the ground in pictures.
Orbs are the soul of a human or animal that is traveling from one place to another. They appear as circles because their shape makes it easier for them to get around. However, the longer they exist in our world, the easier they can transform into a full-bodied apparition.