How nice it would be to have the definite answers, but since nobody does have them, I will begin by describing some of the popular orb theories. These include the proposed explanation of dust along with the more incredible ideas...

DUST

Whenever orbs are captured on photographs, the possibility that it is merely dust or something similar must be looked into and accepted as a possible explanation for some occurrences. Some people are convinced that all orbs are due to dust in one shape or form; this however raises the question of why there are a far lower number of orbs captured on conventional film cameras than on digital cameras. On the Additions link I will go into the standard camera - digital camera scenario. When dust is used as the reason behind orbs, there are two different arguments again - one whereby it is claimed that the dust creating the orbs is present on the camera lens, the other whereby dust in the atmosphere is blamed.

The first argument of dust on the camera lens is invalid for two reasons: Firstly it would not increase the incidence of orbs on digital cameras as opposed to film cameras. Secondly, any dust present on the lens would not appear on the photograph and it certainly would not appear as a small orb as being so close to the lens, it would appear greatly magnified in size which, incidentally, would also make it appear more opaque - hence the dust is not visible. As the apparent size increases, the apparent density decreases.

This leaves the argument of dust in the air which is more plausible and indeed possible. When light reflects off the dust particles and those particles are not in the cameras set focus-range, they can appear orb-like, being diffuse, greyish-white in colour and fairly transparent. Orbs tend to be more numerous when camera flashes are used, which would support this idea as the strong light being emitted from the flash could bounce off the dust and being such a strong light, it would make the dust particles quite bright.

If you look at purposely faked photos where large amounts of dust or scratched-off toilet paper have been used, you can see the difference between these orbs and what I call proper orbs. The faked ones are denser looking and have a central nucleus that is easily visible; this nucleus is the main dust particle while the diffuse blurry light-bubble around it is due to the particle being out of focus. A real orb has no discernible nucleus and can often be seen to contain interesting patterns inside the main sphere, sometimes with different 'layers' being visible. Also, in such staged photographs, the particles are easily visible to the naked eye whilst airborne and sometimes they only produce barely visible orbs on photographs despite the large particle size and quantity in the air. So why do there sometimes appear vast amounts of orbs on a photograph where there is no visible dust in the air or the environment is naturally fairly dust-free?

SPIRITS

Amongst those who believe that orbs are due to paranormal phenomena, there is a belief that the orbs are a manifestation of spirits or that the orb is the spirit itself in the preliminary stages of becoming a full-bodied apparition or at least, trying to materialize. The idea is that the orb is energy and this energy starts off as an orb and then can sometimes build itself into a shape or form which represents the spirit. Another belief is that the orb is not the spirit as such, but is the spirit energy - something created by the spirit or how the spirit's energy appears to us.

There isn't any scientific method that I know of which could tell us if the orbs are spirits beginning to manifest or spiritual energy showing itself to us in the form of a sphere, unfortunately, so we have to leave it to educated guesses along with circumstantial evidence. Not ideal but until the metaphysical can be shown to exist - by way of seeing it, measuring it, examining it in a controlled environment and checking the effects of outside stimuli and thereby taking it from metaphysical to physical - we have no accepted method of postulating agreeable and acceptable theories which can be shown to give the same results time after time. One way of getting a theory which quite a few tend to find more acceptable is by asking a Medium for an explanation. I have never really heard a Medium explain in-depth about orbs, I have only heard them say that they are indeed linked to spiritual presences and that they are spheres of energy. Hence you will quite often hear people refer to orbs as spirit-energy.

What is very interesting is the appearance of orbs on infra-red or 'night-shot' video cameras as they are often called. In these cases, the orbs can be seen to dart about and make some very interesting mid-course changes at acute angles. They sometimes seem to appear from nowhere, zoom across the viewable screen and then fade away or just simply disappear from sight - most often the case with dark rooms and infra-red cameras that only allow for a reasonable increase in brightness of the surroundings. The most fascinating aspect of video-captured orbs is that in my mind, at least, they rule out dust particles as being the culprits since they move quickly and make course changes - sometimes around people - with noticeable variances in speed. In a room with no movement and no draughts, I find it hard to believe that we are witnessing just one dust particle that happens to be visible to the camera and happens to make striking velocity changes.

NATURE

Another rather interesting theory which is allegedly backed up to some extent by experimentation and application of known physics is one that looks upon orbs as being a spherical structure made up of unknown particles - these particles are something which they hope can be further looked into with the aid of quantum physics - and this spherical structure is electrically charged. As some of you may have noticed, non-dust orbs can be seen to have an outer layer or shell; it is believed that this shell is charged with electrons. The more transparent orbs have weaker charges - less electrons - than the brighter more opaque ones.

Also, when looking at high quality close-ups of orbs, some can be seen to have an almost mosaic pattern of many colours making up the bulk of the sphere whilst others seem to have a more constant or solid colour, these latter ones are said to be charged to their full capacity, or stable whereas the 'multi-coloured' ones are believed to be lacking in charge. As the orbs are said to be electrically charged, it is believed that they 'ground' themselves against any materials that will conduct the current to earth potential and that they also share their charge, i.e. one fully charged orb may come into contact with a partially charged one and they will balance themselves electrically so that they have equal charge - the lower charged orb receiving electrons from the fully charged one, just as a full capacitor will pass some of its charge to an empty one, in proportion to the capacitance of the device until both have equal charge.

I will explain why orbs appear to have a darker or distinct circle around them and how this is known to some degree to be a shell or covering of the sphere as a whole after I explain the theory of how and why they show up on film, as this has a bearing on their appearance once captured. Putting the film camera vs. digital to one side for now, it is known that orbs show up best when a flash is used with the camera. This has been explained by some as being due to a property called 'phosphorescence', this is something which occurs with some minerals and is the process at work on the hands of your analogue watch or clock if it is a "glow in the dark" type. When light strikes such substances, the photons (packets of light) knock electrons whirling around the atoms into higher energy states or further-out electron shells. These electrons then fall back down into their normal place, some of their energy having been used to keep them in the higher energy orbit; this leaves them with some leftover extra energy which is emitted as a photon again. This photon is lower in frequency than the original photon which reacted with the electron in the first place, due to its having used some energy up already - hence invisible ultra-violet light can create visible light with phosphorescence by having its frequency lowered to that of light in the visible spectrum (put your watch under a UV lamp).

Now, the idea is that when the intense light from a flash camera bulb hits the electrons in the outer shell of an orb, it knocks these electrons into higher energy states, these electrons then 'jump' back down into their normal states emitting photons in the process which we see on the camera images. However, unlike normal phosphorescence effects which last a while (presumably because the electrons stay in their higher energy states for various and sometimes relatively lengthy periods of time before using so much energy that they can no longer survive in the higher electron orbit) orbs seem to have an immediate phosphorescence effect, whereby the light is emitted in one go with no lasting emission. There is at present, I believe, no explanation for this process being so rapid if it is indeed the actual process happening.

The basis behind the belief in the outer shell of an orb is quite simply that a shell around the orb made of electrons that was mainly responsible for the emission of light would create a circle around the perimeter of the orb as the 'centre' of the orb's body would be light coming from the 'back' and 'front' of the shell which appears as a large area and light coming from the 'sides' would create the circle as there is light coming from those sides but it's only being seen as a thin line, so it looks different and stands out.