All the energy we get from the sun comes from the fusion of two hydrogen nuclei into the other, heavier, helium nucleus. This reaction, resulting from same phenomenon’s as those responsible for beta radioactivity, allowed elements heavier than hydrogen to be generated, like carbon, oxygen, nitrogen, phosphor, silicon, and iron. Without radioactivity, our planet would have frozen over long ago and life on Earth would be impossible. Radioactive processes in the Earth core slowly release the heat essential for our survival, constantly maintaining the temperate climate we take for granted. All life has developed in a constant shower of radiations, adapting to it and occasionally using it for its own benefit.

Radiations are an omnipresent. Whether we go on mountain-climbing expeditions, go down to the cellar to get a bottle of wine, or get aboard a plane, we will always be exposed to it: cosmic radiations from space resulting from deep-space gamma trays, radiations from underground out of thorium and uranium. Even our bodies are radioactive, containing as they do millions of atoms of radioactive substances such as radioactive carbon 14 and potassium 40. Apart from the countless natural sources of exposure, the harnessing of radiation by humanity has led to a multitude of applications that we use every day. Even though the main artificially generated exposure comes from medical examinations (such as X-rays), we use radioactive substances and radiations to sterilize food, prolong its shelf life, and prevent fires in public places... We must not forget, however, that all these common sources of radiation, whether natural or artificial, remain virtually harmless.