As part of my quest to learn more about what EMFs are and why EMF meters are used so much in ghost hunting, I'm starting at the very beginning: What are EMFs (electromagnetic fields)?
To answer this question, I'll be trying to rely mostly on .gov websites[^1] and well-vetted sources like Wikipedia, because there's a lot of obvious misinformation about EMFs online and I'm trying to avoid repeating unsourced claims.
Types of fields
To explain it the way this government website does, there are electric fields and magnetic fields.
- Come from voltage, which is the amount of work it takes to move electrons through a wire. (This site compares it to water pressure; this one calls it a measure of "push" available.)
- The higher the voltage, the higher the electric field.
- These are produced both when a device is on and when it's off.
- Electric fields can not move easily through barriers like walls, people and animals, and other objects.
- Are created by the current (the flow of charge through the circuit, i.e. wires and electronics).
- The stronger the current, the stronger the magnetic field.
- These are produced when current is flowing (usually when a device is turned on.)
- Magnetic fields can easily move through walls, people and animals, and other objects.
Put 'em together, and you've got electromagnetic fields (EMFs).
Electromagnetic radiation (EMR) contains both electric fields and magnetic fields; it's what creates the forces in EMFs.
As a word, "radiation" has an awful connotation, but here it seems be generally used as a synonym for "field." That's just a good thing to have in mind when researching EMF stuff, because the word "radiation" comes up a lot, but it's not always the bad kind. That's reserved for high-frequency EMFs.
Types of EMFs
Speaking of, there are two main types of EMFs.
High-frequency EMFs, aka ionizing radiation:
- Examples: x-rays, gamma rays, therapeutic radiation
- These can cause DNA damage and chemical changes in cells (it's what you probably think of when you hear the word "radiation").
- These have short wavelengths.
Low-frequency and mid-frequency EMFs, aka non-ionizing radiation:
- Examples: power lines, appliances, microwaves, radio waves, wi-fi, cell phones, infrared radiation, visible light
- Extremely low frequency EMFs (ELF-EMFs) also fit under this umbrella. Those are emitted by power lines, electrical wiring, and appliances like hair dryers and electric blankets.
- Ditto with radiofrequency radiation, which comes from phones, smart meters, tablets and laptops, AM/FM radio and (older?) TV signals, radar, satellite stations, MRIs, microwaves, TV and computer screens, wi-fi.
- These have not been shown to directly damage DNA or cells.
- These have long wavelengths.
The electromagnetic spectrum
NASA has a helpful graphic showing the spectrum and giving examples of how different the wavelengths in high and low-frequency EMFs are. For scale: a low-frequency field like AM radio has wavelengths as long as a football field, while a high-frequency field like gamma rays have wavelengths the size of an atomic nuclei. So there's quite a range.
This relatively simple explanation really strained the boundaries of my comprehension of physics (even though I've been trying to teach myself about electrical circuits for the last six months). But hopefully it's a simple explanation of the subject.
Anyway, watch this space for more labored descriptions of my EMF-related research.
General disclaimer: I'm a paranormal researcher trying to learn more about EMFs, not an expert. I'm learning in public, not being an authoritative voice.
[^1] I'm not claiming that everything the government says is 100% true all the time, on all subjects. But at least a lot of agencies put effort into ensuring that their claims are well-sourced and based on actual science, which is what I'm looking for here.