Ah hell, here is a definition of orbs from a paranormal site...( they are being honest )
Orbs: What Are They Believed To Be?
Orbs are believed by a large number of people, both new groups, experienced and people who are capturing them, aka, non-ghost hunters, to be spirits caught on film.
Or, another popular belief is that an orb, is a ball of energy, spirit energy that’s free floating, in the environment. It is “common knowledge” that energy is most stable in the form of a sphere, which is the limited physics background of the belief, and I do stress limited. I have also hear of orbs being spirit guides, demons, astral creatures and oddly enough " evolved spirits".
In reality, there is no proof or scientific back up for any of this. Now that we know what the most common beliefs are in regards to orbs, let us proceed onto the truth.
What orbs REALLY are. Orbs have been scientifically debunked as a modern inception with no pre-recorded example prior to the availability of CCD lens (digital camera) technology and it's inferior ability to focus (this is especially true of cell phone cameras which cannot in any way compare to professional grade or even consumer grade stand alone cameras), "supernatural orbs" make up the predominant presence of 'ghost photos' on the Internet.
There are two main types of orbs reported, both of which are caused by particulate matter in the air. The first type is Naturalistic Solid-Type orbs, and the second type is Liquid-Based orbs. Below we shall explore the two and see what the difference is. First off, cameras.
What Type Of Cameras Most Often Capture Orbs? Digital vs. Film.
Naturalistic orbs are most commonly gained using digital cameras and built-in flash thought not always.
While photographers with archives of photos report having occasionally seen "orbs" in their photos gained with film cameras, no evidence has been presented that this is not a modern light artifact error arising in CCD lenses both in standard off the shelf cameras and cell phone cameras and the recent rise in reports of orb photos may be directly related to the common availability of digital cameras and associated rise in the number of pictures taken. It should be noted also that the size of the camera is another consideration in the recent proliferation of orb photos.
As film cameras, and then digital cameras, have steadily shrunk in size, reports of "orbs" increased accordingly. As cameras became smaller, the distance between the lens and the built-in flash also shrank, decreasing the angle of reflection back into the lens causing less focus on small light artifacts and thus an orb like appearance.
A flash does not need to be present. Any light source that reflects or refracts from particulate matter (dust, moisture, etc) in the air (even though we can’t see it’s there moving on air currents) and that enters the cameras lens (which it does otherwise you wouldn’t have a picture in the first place) can cause an orb artifact to appear.
The Main Causes of Orbs:
There are a number of naturalistic causes for orbs in photography and videography.
*Solid orbs - Dry particulate matter such as dust, pollen, insects, etc.
*Liquid orbs - Droplets of liquid, usually water, e.g. rain.
*Foreign material on the camera lens
*Foreign material within the camera lens
*Foreign material within the camera body
More on this here :
http://ssprstn.tripod.com/id65.html