Radiations
Radiations

The natural radioactivity exists on the Universe since its origin, deeply participating of life. That is because earth, living been and everything that surrounds us is radioactive. Natural radioactivity is equally present in the human body interior because the food and water that we absorb and the air that we breathe contain atoms that are naturally radioactive.

The most natural radiation source is the sun. All stars send ionizing radiations and other kinds of radiation. Known as cosmic radiation, they heat the Earth and consequently all the people in the world are exposed to them. The Earth atmosphere can partially shield it.

Since Universe constitution the radioactive atoms disintegrated themselves. The biggest part disappears, becoming stable atoms. Whatsoever, few are continually radioactive for billion years still, according to series of transformations that should take them to definitive stability; others create themselves everyday.

This way, the highest areas are more exposed to cosmic lightning. During intercontinental aerial journeys, people are also more exposed to the cosmic lightning. The other natural radiation sources are soil, water and air because all natural radioactive elements are present in small proportions in these materials. In the air the radioactive radonium gas concentration grows in any closed environment with little air renovation. Radonium gas emanate from the sand used in construction.

The Artificial Radioactivity is a phenomenon of the same nature as natural radioactivity. However, the emissary nucleons are produced in laboratory or nuclear reactors.

Natural radioactivity – The oblivion of a uranium rock on a photographic virgin film led to the discovery of an interesting phenomenon: the film was veiled (marked) by “something” that came out of the rock, at the time, denominated lightning or radiations. Other heavy elements with mass closed to uranium like radium and polonium also had the same property. The phenomenon was called radioactivity and the elements that had this property were called radioactive elements. It was proved that a very energetic nucleon, because of it particle or charge excess, tends to establish itself, emitting some particles.

Nucleons with energy excess tend to stabilize emitting particles or electromagnetic waves.

Bombing stable nucleons it is possible to manufacture radioisotopes that did not exist in nature (with nuclear reactors and particle accelerator machines development, a lot of radioisotopes could be “made” using as raw material stable isotopes. Due to this, artificial radioactive series appeared, some of short duration). These radiations transformed atoms in ions on their way, which means that they are ionizing radiations.

Radiation is ionizing when it has the necessary energy to pull out one or more electrons from atoms or from the molecules of the irradiated environment. That is the case of radiations a, b and c and also X-ray and some ultraviolet.

It is necessary to observe, however, that ionizing radiation (deriving from natural or artificial process), depending on the intensity and exposition time, can be dangerous for the organism.

The radioactive isotopes, with the property of emitting radiations, have many uses. The radiations can cross through the material or be absorbed by it.

By energy radiation absorption cells or little organisms can be destroyed. This property, which normally is inconvenient for living beings, can be applied in their benefit when used to destroy bad cells or microorganisms.

Nowadays several artificial radioisotopes are created for numerous applications, mainly in chemistry, biology, medicine, archeology, Earth and Universe science, and in agro-feeding.

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Radiations