Last time we discussed some of the broader issues around the phenomena of cold spots.  This time I wanted to dig down into a more narrow discussion of the physics involved.  Temperature - heat - is energy, and there are several ways to "harvest" heat in order to use it for energy.  But could ghosts be harvesting heat literally out of thin air in order to power their appearances?

Many scientifically minded investigators will cite the Peltier effect as a possible explanation for what's going on when a cold spot appears.  The Peltier effect is a real thing, and in fact it is used by some small refrigeration units and in some specific applications.  But it's incredibly inefficient compared to other methods of cooling.  

To sum up the Peltier effect, if you connect two different metals together and run an electrical current through them, one side will get hot, and the other side will get cold.  This happens because of the different levels of conductivity between the two metals.  (The Peltier effect can also happen on a geologic scale, when two outcroppings of different minerals get electrified thanks to something like seismic activity or a lightning strike.)

To create the Peltier effect all you need is two slabs of metals that conduct at different levels, plus an electrical current.  Because it requires no moving parts, Peltier coolers are used in some military applications.  They can also be found in portable and RV refrigerators, since regular refrigerators have to be kept upright in order to work.

Obviously, the Peltier effect can't literally be responsible for cold spots, because they don't involve slabs of metal.  Interestingly, ghosts are often associated with electromagnetic radiation (EMF) which is basically an electrical current in the air.  So they do have half the equation - electricity - available to them.

However, discussions of cold spots always raise a bigger question.  As we all know, the second law of thermodynamics is such that heat is never destroyed - it just goes somewhere else.  In the Peltier effect, heat is sucked from one slab of metal and emitted from the other.  In a refrigerator, heat is sucked out of the interior and blown out the back.  In an air conditioner, heat is sucked out of your home and blown outside your window.

So if a ghost is sucking the heat out of the air… where is the heat going?

In fact, if cold spots were being caused by ghosts, then we would be associating hot spots with ghosts, as well.  As a ghost moved past you, it would be slowly emitting the heat that it had sucked out of the air.  Which would feel like a WARM breeze moving past you in the night.

I know that your mind just ran a little clip of some FLIR tape of a ghost.  But consider this: FLIR cannot see cold spots in the air, it can only record the temperature of a physical object.  If FLIR cannot see the cold spot caused by a ghost sucking heat from the air, then why would it be able to see the hot spot caused by the ghost emitting that same heat?