Radiation was first detected by a French scientist called Henry Becquerel, who was conducting an experiment with photographic plates. He found that elements like uranium, thorium, and potassium emitted certain rays, which had an effect on these plates, making them foggy. However, the type of radiations and their effect on living beings, vary drastically. There are different sources of radiation. Some of it is inherent in the planet's atmosphere, and living beings have an inbuilt mechanism to deal with it. Other sources of radiation are activities like nuclear fission and fusion.
Radiation consists of three types of rays, each with a different capacity to penetrate bodies. These are alpha, beta, and gamma rays. Radiation is not harmful in all cases. In fact, some types of radiations are unavoidable, like cosmic radiation, which originates from stars. The Sun radiates cosmic energy produced by nuclear reactions on its surface, which consist of short wavelength emissions of electrons and neutrons.
A lead object, one inch thick, can be easily penetrated by such radiations. Thus, you can have an idea about the effect that cosmic radiations might have on living beings. As you move upwards from the surface of the Earth, these effects go on increasing. Therefore, frequent fliers and astronauts are more exposed to cosmic radiation than others.
Harmful Effects of Radiation
Overexposure to these radiations can alter the DNA of animals. This is caused by the ionizing effect, which is produced by this phenomenon. If the rate of ionization is significantly large, it can result in permanent damage of tissues. Sunburn, melanoma, or different types of cancers are caused by overexposure to nuclear radiations from the Sun, or even from nuclear tragedies. Kinetic energy released due to the highly penetrating shock waves that are generated by a nuclear explosion, or from the use of nuclear weapons, triggers thermal radiation. Burns are the most immediate and primary effects in such cases.
Thermal radiation is approximately 35 - 45% of the total energy released in a nuclear explosion or nuclear test. This is a sufficiently large quantity, to permanently alter the gene structure, and introduce hereditary problems, as is evident from the bombings of Hiroshima and Nagasaki. The subsequent generations were found to have several abnormalities. There is a parameter called radiation absorbed dose (rad), which gives an idea about the effects of radiation that bombards a human body. 50 to 150 rad causes alterations in the blood with symptoms like nausea, fatigue, and vomiting.
In case of exposure between 150 - 1100 rad amount, if not treated immediately, a victim may die in 30 days. For all levels above this, the central nervous system of the body fails, and loses control over all bodily functions, and death may occur in a matter of few days or even hours.
The following are some advantages of radiation.
- Radio therapy (for treatment of cancers) and X-rays employ controlled exposure to radiation.
- Radio carbon dating is another application, where nuclear energy is used to determine the properties and uses of several radioactive elements, and also to determine the age of fossil samples.
- Level detectors, smoke detectors, and leak detectors employ the use of radiation.
- Sterilization of medical equipment, food, and detecting malfunctioning body parts can also be achieved through a limited exposure to radiation.
Like many other scientific discoveries, radiation can be put to both constructive and destructive uses. It is the responsibility of humanity to use this powerful tool for the benefit of nature, and for all of its elements.