. I n f o r m a t i o n .
The moons position has an affect on the earth's magnetic fields. It is assumed that when a full moon or new moon is in effect, spirit energy is stronger and more easily detected.
Current Solar Data
Many "ghost hunters" speculate that spirits use engery to alter electromagnetic fields that surround us. From your toaster to your TV. The alterations caused by this energy can be detected with an EMF detector. When solar flares occur, the air becomes bloated with excess energy. The more energy there is in the air, the more energy is available for a spirit to connect with and alter.
To be honest I cant answer this, Skeptics say its water condensation or dust on the camera lense. I chose this particular photo,(of my daughter) as an example of the "possibility". They say children can see ghosts better then the average joe. Why? maybe its that children are more aware of there "natural" surroundings. click here for more information
Humidity as well as rain, mist, snow, smog, fog, ect, can cause a false positive in your photos. Its best to preform a "ghost hunt" when your humidity is low, with no chance of precipitation, or other weather anomalies.