A great deal seem to believe everything called “radiation” to be dangerous.  I think it is because the ionising was first payed attention to as such.  Which has then been overgeneralised to apply to all radiation.  However, most of what is called “radiation” is not ionising.  As such it can be considered harmless.  At least in the amounts people may be exposed to without them noticing.

One of the main types of radiation is called particle radiation.  The ones relevant in context consists of the following particles:

• Neutrons are made of part of atomic nuclei.  They are formed by nuclear reactions and soon decay afterwards if they are not captured by hydrogen nuclei.  So they can be stopped by substances containing large amounts of hydrogen.

• Hydrogen nuclei consists of atomic nuclei of different variants of hydrogen.  Such are ionising but does not penetrate particularly far in air.

• Atomic nuclei of helium and heavier elements don’t penetrate skin.  In contrast it is dangerous to get into the body things emitting them.

What is today called cosmic radiation is particle radiation from space.  Most of it is captured by the Earth’s magnetic field.  The rest is nearly entirely absorbed by the Earth’s atmosphere.  So it is only in space we need to worry.

The other main type of radiation is electromagnetic radiation.  It does not come from electricity but is a collective name for the following:

• Gamma rays.

• X-rays.

• Ultraviolet light.

• Visible light.

• Infrared light.

• Heat.

• Microwaves.

• Radio waves.

There are some overlap between infrared light and heat and between microwaves and radio waves.  At the other end are ultraviolet light, X-rays and gamma rays.  Out of electromagnetic radiation it is only those which are ionising.  Both gamma rays and X-rays are stopped by the Earth’s atmosphere.  It stops most of the Sun’s ultraviolet light too.  What the atmosphere does not stop is relatively easy to protect against.  I am talking about clothes and sunscreen here.

Finally, there is a confusing between radiation and radioactive contamination.  Exposing things to radiation does not need to make them radioactive.  It is only neutron radiation which can create radioactivity.  Food irradiation is done with gamma rays.  When material has absorbed gamma rays they cease to exist.  Same applies to microwave ovens which are commonplace.  Microwaves are not even ionising.  If microwave ovens are so dangerous why don’t more die young?  I think it is rather a matter of which food is heated.  Is the food unhealthy from start the heating method does not matter much.

 

Uploaded on the 10th of April 2024.