Ironically, Ghosts are one aspect of horror that I fail to justify with science. The essence of a human being materializing or affecting objects in reality. For me, Ghost are purely fantasy. So much so I believe that they are among the only fantasy elements available. Angels and demons are right there with ghosts.
Just for a mind play, Lets look at ghosts.
Matter has mass. Mass is affected by temperature and gravity for sure, right?
For all intents and purposes we could say that the soul is a chemical electric feild.
Keyword, Chemical.
A ghost is supposed to be a person that has not passed to another plane (dimension, reality, who cares).
You can't pick up a ghost and throw it.
You can't see a ghost most of the time (unless it wants you to...lol)
A ghost rattles chains, slams doors and just causes a racket in your house moving things, breaking things and scaring little children.
According to Ghostbusters (Cool Movie) ghosts have a subsatnce called exctoplasm. It is a reality slime that a ghost transfers to our real world.
They affect the temperature, static electricity and produce sound.
Sound is vibration and is transmitted thru an object like metal, wood, water or air. The vibration must come from a source able to affect the medium it is encased in. That is why our thoughts do not make sound. A picture does not make sound unless the frame is dropped. A drawing does not make sound unless the paper is crinkled.
The appearance of a ghost. We see because light is reflected onto our retnas from another object. We don't see sound because sound is a wave. We do't really see light either. We see the reflection of light or if you are stupid enough to look directly at the sun, you will see light passing thru our atmosphere right before you go blind, but, we don't actually see the light itself. The ghostly apparition has to have mass in order to reflect the light.
That mass, no matter its volume is affected by gravity. The Earth has a pretty substantial pull on every molecule we have ever encountered. That graviity would affect the ghost. Keeping it to the floor. Without that gravity, a ghost would pass right thru everything, including the Earth. Your ghost is now out in space, never to be seen again because the Earth both rotates, wobbles and revolves. The Sun wobbles and rotates around the galaxy as well. Goodbye Ghost.
Nope, I just can't justify them...