Orbs are balls of light which are mainly white but can be seen in other colours like red. What these really are as lead to much debate, Orbs have been put down to paranormal phenomenon, but some which are caught on camera can have a very normal explanations, one of the most popular.
Theories is that orbs are a source of energy being drawn from a source e.g batteries, power lines etc so the spirit can manifest itself. But it thought these lights can be caused by other things such as dust particles or a refraction of light in the camera lens. So the debate goes on as to what these really are and if they really are paranormal.