What is it?
Yes, the dictionary has a definition for ‘ghost’. That doesn’t mean that science would know exactly what to do with a ghost – even if it walked in the front door of NASA, volunteered, and didn’t dissipate.
The stories about ghosts are contradictory, but they follow similar themes.
Visual: Ghosts (or spirits or whatever they are) are alleged to appear as ‘shadow people’ or as apparitions. This means that whatever energy form(s) is there can either absorb or block photons (shadow people) or emit photons (apparitions). There is no known energy field or substance that can do anything of the sort, unless it is highly classified and belongs to the Department of Defense. And even at that possibility, it is more dense and heavier than air, and probably weighs many pounds.
Auditory: Ghosts are alleged to make noises like falling pans, clinking chains, slamming doors, voices (talking, singing, moans), or footsteps without actually moving any objects. Are they causing vibrations in the air or are they manipulating your hearing internally?
Thermal: Ghosts are alleged to be able to make cold spots or hot spots. Usually a source of energy has a tendency to create heat since most processes waste energy (why light bulbs get warm for instance). How do you make a cold spot in the middle of the room without a condenser?
Kinetic: Poltergeists are alleged to be able to throw physical objects, manipulate light switches, move chairs, interfere with electronic devices, or play with toys. This requires energy, but there is nothing detectable but the air itself. Can they really touch us, too?
So where is science supposed to start? It would be bad enough if ghosts only did ONE of these sets of things.
On the other hand, I think if ghosts are truly a form of ‘energy’ we should be planning on converting the old insane asylums into energy conversion/production facilities. Are ghosts a renewable energy source that we can tap into? Why not? Then they can either get to work keeping our lights on, or finish crossing over, already!
Don’t worry. I think crazy Uncle Harold is safe awhile longer from being used as a battery.