"Ghost Detectors" So I work at a popular tourist attraction that is well known for being "haunted." Needless to say, I get a lot of people asking about ghosts. I don't believe in ghosts. I need some kind of evidence to acknowledge stuff of the kind. Anyway, a week or two ago this couple showed up with a "ghost detector." I looked at it, and it was meter that measured milligauss. My physics class just blew over electromagnetism, so I only know what I've gathered from the internets. This is a measurement of the strength of an electromagnet field, yes? When I held it up to an exit sign, it went haywire. How significant is 1 milligauss? This thing went from like 1.5 to 6.0 milligauss. Thanks.