Tuesday, 28 August 2012

EMF meters and ghosts - an accident of history?

Suppose someone showed you a graph of the output, over time, from a photometer (which measures light intensity) that they had captured while witnessing an apparition. The graph clearly showed light levels rising suddenly, as the alleged ghost appeared, and then dropping as it disappeared. Would you regard that as compelling evidence that they'd really seen a ghost?

Magnetic frequency chartI suspect many people would remain unconvinced. While the graph clearly showed that there had been a temporary increase in light levels, there could be any number of natural causes to account for such an event. All a photometer does is measure overall light levels. It can give few, if any, clues to the nature of the phenomenon responsible for that light.

Now suppose the same person said they also had an EMF meter running at the time and it showed a 'spike' while the ghost was visible. I suspect many people would consider the EMF 'spike' to be much better evidence of a ghostly presence. But why?

Take the graph, above, for instance. It shows frequency (bottom axis) against magnetic flux density ('field strength') over a short sample period, made using a magnetometer. The instrument was near to a washing machine during its spin cycle. The huge frequency peak at 50 Hz is caused by the mains supply to the appliance (standard frequency in Europe). The big peak down near 1 to 3 Hz region is caused by the rotation of the washing machine drum. I'm not sure what is causing the small peak at 45 Hz but it is certainly related to the operation of the machine because it stops when the machine is off. Maybe it's a water pump. It would be easy to test that idea by simply listening for the pump and noting when the 45 Hz peak appears. If you put an EMF meter in the same physical position, near the washing machine, you see a steady high reading (with slight wobbling) during a spin cycle. Without frequency information, EMF meters cannot even identify whether there are single or multiple sources of a field, far less offer any clue as to what any of them might be.

Photometers and EMF meters give an overall reading of light and electromagnetic fields respectively. Neither allow us to easily identify possible sources. And yet photometers are hardly, if ever, used in ghost research whereas EMF meters are ubiquitous. So, why is this?

My best guess is cost! There is an excellent, cheap alternative to the photometer which provides much more information and allows the identification of sources of light - the camera. The alternative for the EMF meter, which allows sources of magnetic fields to be identified, is the magnetometer. However, it is both much more expensive and more difficult to use. It is my opinion that, if magnetometers were as cheap as EMF meters, they be used widely instead of the meters. So we may be stuck with EMF meters simply because of an economic accident of history!

But we are where we are. Anyone choosing to use an EMF meter should be fully aware of its limitations.

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