We might think of nuclear reactors or alien movies when we think the word radiation, but the reality is far less intense. Radiation is simply the term that refers to energy that travels in the form of particles or waves, often through great distances in space.
There are two chief categories of radiation, ionizing and non-ionizing, and the major difference between them is how harmful they are to living things. Ionizing radiation is the form that is most harmful, but that doesn't mean that exposure to certain types of non-ionizing radiation can't have negative effects.
Of the ionizing radiation, there are three types: alpha particles, beta particles, and gamma particles. Alpha radiation is the least effective because it can be stopped by simply holding up a sheet of notebook paper. Beta and gamma, on the other hand, are rather serious and barriers of specific materials and thicknesses, sometimes even as many as several feet thick, are required to stop the particles.
Ionizing radiation can be very harmful to humans and other living creatures.
1. Non-Ionizing Radiation
Non-ionizing radiation, the kind that is of very little harm to living creatures, includes things like light and heat, such as from light bulbs and hair dryers, sound from radio or television speakers, frequencies that control remote controls, and even magnets. Cordless phones, computer screens, and other technology have been questioned repeatedly over the years but have always been proven to be safe given the amount of exposure a person is likely to have.
2. Ionizing Radiation
This is the type of radiation that can be harmful or lethal to organisms in the wrong doses. It includes things like x-rays, solar radiation, radiation treatments for cancer or other medical conditions, repeated exposure to airport security scanners, radiation found in space that astronauts are exposed to, and many other sources. Legislation has been proposed repeatedly to ensure that the amounts of exposure to harmful radiation is limited in order to protect the public.
3. Natural Radiation
Recent experiments have shown that flying in an airplane at altitude exposes passengers to radiation due to the closer proximity of the aircraft to the sun's radiation waves, and due to the thinner atmosphere at that altitude which allows more particles to reach the passengers. The atmosphere is denser at ground level and therefore blocks many of these waves. Studies have shown that a person who flies non-stop for more than 300 days-never once coming down to ground level in that time-is still within the safe limit for exposure.