Greg Pocha wrote at 2013-08-13 23:49:55
I am Greg Pocha, another expert here at All Experts in the category of Paranormal Phenomena. I would like to offer some additional information.
You state that the room was pitch black. If that were the case then a shadow caused by an external object would have been impossible to see. You also would not have been able to see any reaction from your dog. Therefore there must have been some light in the room. With light in the room one can not rule out a shadow being caused by an external object
From a paranormal point of view it is possible that a ghost was just passing through. You ask if you have a ghost - likely not. Ghosts are free to wander [some are called wandering ghosts] and may occasionally pass through our space. Seeing a ghost is not indicative of a haunting, it merely means that you saw a ghost. Ongoing activity indicates a haunting and from what I gather this is not an issue in your case.
Also bear in mind that animals also have ghosts and that an animal is more likely to 1- wander and 2- appear as a shadow.
I hope that this helps shed some more light on your question.
Greg Pocha / All Experts / Paranormal Phenomena