Testandmeasurementtips.com recently received a letter from a man who heads a group of paranormal researchers. It was a serious letter. To summarize, the group concluded that there was no legitimate method of recording the activities of alleged persecution. But the writer had a question for us, prompted by a piece gauss meters and ghost hunting TV shows we did a few years ago. Their question: Can something consume energy without emitting just a field?
With this in mind, we may be able to clarify things by looking at what exactly causes electric and magnetic fields.
The simple answer is that electric fields are caused by electric charges, and magnetic fields are caused by electric currents.
There may be some confusion on the above points. It is possible to find publications on the Internet that seem to suggest that changing electric fields cause magnetic fields and vice versa. Perhaps the easiest way to illustrate that this idea is wrong is to study the typical way in which electric and magnetic fields are depicted in physics books. The typical representation shows sinusoidal electric and magnetic fields moving synchronously with each other. But if one of these fields has caused the other, one can expect to see some delay in the time between them – say, the electric field changes first, followed by some proportional change in the magnetic field. But this is not happening. The two types of fields change perfectly in step with each other.
Essentially, every electric charge that moves has both an electric and a magnetic field around it. Both magnetic and electric fields do not interact. This means that the electromagnetic field of a large object made up of billions of particles is actually just the sum of the individual fields of each particle. So with that in mind, the electromagnetic field found at a point in space is simply the effect of slowing down in time from the position, speed, and acceleration of charge at an earlier time.
In addition, the only real detectable effect of electromagnetism is that charges can exert forces on other charges. In this way, instruments designed to detect electric or magnetic fields do so by measuring how the charges inside the instrument are affected by the EM field. In short, EM fields are created by charges and their motion. Their effects are observed only when they produce forces on other charges at a later time.
One additional point that needs to be explored is how charges in nature can be accelerated in the first place. There are many ways, but one main means is through heat. Remember that objects retain heat through the vibrations of their atoms. Adding heat to an object causes the atoms of the object to vibrate more strongly. The more heat is added, the stronger and higher the frequency of vibrations. Thus the temperature of the object is proportional to the vibrational frequency of the atoms in it.
Remember that every atom has an electric field around it. This electric field goes to infinity, although its intensity decreases with distance 1 at the distance squared. When an atom vibrates, an observer at some distance will see the intensity of the field (ie the motion of the wave) moving at the same speed as the vibration of the atom. Therefore, atoms that vibrate fast enough due to heat energy will eventually emit visible light frequencies. The classic example is a steel factory, where the metals in the process glow orange and white hot.
Materials that are not hot enough to emit light still emit lower frequencies. Planck’s law describes the intensity (actually the spectral density) of the electromagnetic radiation that a body emits at a given temperature when it is not heated or cooled. In general, Planck’s law shows that the higher the temperature of a body, the more radiation it emits at each wavelength. Conversely, relatively cool objects – those that are not hot enough to emit visible light – do not emit much radiation at any frequency.
In general, we must say that the clinical discussion of EM radiation tends to take the topic out of the realm of the paranormal.