Nothing happened Tuesday in space science, is the conclusion reached by this researcher. As a hard scientist here at ScientificBlogging, I find interesting topics to write about twice weekly. However, today, there was nothing. Nothing at all happened in science, at least involving space, or astronomy, or Mayans (who, according to /., apparently predicted the apocalypse in 2220, not 2012 as commonly misreported).

In looking at the concept of a ghost, the first problem one encounters is defining exactly what is meant by such an apparition.  It seems that the general view over history is that ghosts represent some aspect of a once living individual that may have occasion to make itself known.  This is generally considered to be a soul, or some animating spirit, so for our purposes that loose definition will do.

I won't consider the problems of why such an entity would be geographically confined, or even what such a thing means.  Instead let's consider what it takes for a ghost to engage in a haunting.