Solar radiation and its effect on the human body and climate
The blinding sun disc at all times stirred the minds of people, served as a fertile subject for legends and myths. Since antiquity, people have guessed about its impact on the Earth. How close were our distant ancestors to the truth. It is the radiant energy of the Sun that we owe to the existence of life on Earth.
What is the radioactive radiation of our luminary and how does it affect the terrestrial processes?
What is solar radiation
Solar radiation is a combination of solar matter and energy entering the Earth. Energy is distributed in the form of electromagnetic waves at a speed of 300 thousand kilometers per second, passes through the atmosphere and reaches the Earth in 8 minutes. The range of waves involved in this "marathon" is very wide - from radio waves to x-rays, including the visible part of the spectrum. The earth's surface is under the influence of both direct and scattered by the earth's atmosphere, the sun's rays. It is the scattering in the atmosphere of blue-blue rays that explains the blue of the sky on a clear day. The yellow-orange color of the solar disk is due to the fact that its corresponding waves pass almost without dispersion.
With a delay of 2–3 days the earth reaches the “solar wind”, which is a continuation of the solar corona and consists of the nuclei of the atoms of light elements (hydrogen and helium), as well as electrons. Naturally, solar radiation has the strongest effect on the human body.
Effect of solar radiation on the human body
Electromagnetic spectrum of solar radiation consists of infrared, visible and ultraviolet parts. Since their quanta have different energy, they have a diverse effect on humans.
The effect of infrared radiation is the thermal effect, which is accompanied by the expansion of blood vessels, increased blood flow and skin respiration. There is a relaxation of blood vessels and muscles, with analgesic and anti-inflammatory effect. Mild heat stimulates the formation and absorption of biologically active substances.
- Visible radiation has a significant photochemical effect, due to which processes that are very important for the organism take place in the surrounding tissues. It is the visible light quanta that intensify the work of the visual analyzer, and the person sees the world in all the variety of colors. Sunlight activates metabolic processes in the body, stimulates the work of the cerebral cortex, improves the emotional state of a person. It is light that synchronizes the daily and seasonal rhythms in humans, determining the time of sleep and wakefulness. Their violation leads to insomnia, deterioration of working ability and depression.
- The ultraviolet part is a vital factor. Its deficiency leads to a weakening of the immune system, exacerbation of chronic diseases and functional disorders of the nervous system, inhibits the production of vital substances.
Extremely large and hygienic value of solar radiation. Since visible light is a decisive factor in obtaining information about the outside world, a sufficient level of illumination should be provided indoors. Its regulation is carried out in accordance with SNiP, which for solar radiation are compiled taking into account the light-climatic features of various geographic zones and are taken into account when designing and building various objects.
Even a surface analysis of the electromagnetic spectrum of solar radiation proves how great the influence of this type of radiation on the human body.
The distribution of solar radiation throughout the Earth
Not all radiation coming from the sun reaches the surface of the earth. And there are a lot of reasons for this. Earth staunchly reflects the attack of those rays that are destructive for its biosphere. This function is performed by the ozone shield of our planet, without missing the most aggressive part of ultraviolet radiation. The atmospheric filter in the form of water vapor, carbon dioxide, dust particles suspended in air largely reflects, scatters and absorbs solar radiation.
That part of it, which overcame all these obstacles, falls on the surface of the earth at different angles, depending on the latitude of the terrain. Life-giving heat from the sun is unevenly distributed across our planet. As the height of the standing of the sun changes over the year, the air mass over the horizon changes through which the path of the sun's rays passes. All this affects the distribution of the intensity of solar radiation throughout the planet. The general trend is this - this parameter increases from the pole to the equator, since the greater the angle of incidence of the rays, the more heat gets per unit area.
Maps of solar radiation allow us to have a picture of the distribution of the intensity of solar radiation over the Earth’s territory.
Effect of solar radiation on the Earth’s climate
The infrared component of solar radiation has a decisive influence on the Earth’s climate.
It is clear that this happens only when the sun is above the horizon. This influence depends on the distance of our planet from the Sun, which varies throughout the year. The Earth's orbit is an ellipse, inside which the Sun is located. Making its year-long journey around the Sun, the Earth then moves away from its star, then approaches it.
In addition to changing the distance, the amount of radiation entering the earth is determined by the inclination of the earth's axis to the orbit plane (66.5 °) and the change of seasons caused by it. In the summer it is more than in the winter. At the equator, this factor does not exist, but as the latitude of the place of observation increases, the gap between summer and winter becomes significant.
In the processes occurring on the Sun, there are all sorts of disasters. Their impact is partly offset by the enormous distances, the protective properties of the earth’s atmosphere and the earth’s magnetic field.
How to protect yourself from solar radiation
The infrared component of solar radiation is the coveted heat that residents of middle and northern latitudes are eagerly awaiting for all the other seasons of the year. Solar radiation as a health factor is used by both healthy and sick.
However, we must not forget that heat, like ultraviolet, is a very strong irritant. Abuse of their action can lead to burns, general overheating of the body, and even exacerbation of chronic diseases. Taking sunbathing should follow the rules of life that have been proven. Especially carefully you should sunbathe on clear sunny days. Infants and the elderly, patients with chronic tuberculosis and problems with the cardiovascular system, should be content with diffused solar radiation in the shade. This ultraviolet is enough to meet the needs of the body.
Even young people who do not have any special health problems should be protected from solar radiation.
Now there is a movement whose activists are against tanning. And not in vain. Tanned skin is undoubtedly beautiful. But the melanin produced by the body (what we call tan) is its protective reaction to the effects of solar radiation. There is no benefit from tanning! There is even information that tanning shortens life, since radiation has a cumulative property - it accumulates throughout life.
If this is the case, you should carefully follow the rules prescribing how to protect yourself from solar radiation:
- strictly limit the time for tanning and do it only in safe hours;
- Being in the active sun, you should wear a wide-brimmed hat, closed clothes, sunglasses and an umbrella;
- use only high-quality sunscreen.
Is solar radiation dangerous to humans at all times of the year? The amount of solar radiation coming to earth is connected with the change of seasons. At mid-latitudes in summer it is 25% more than in winter. At the equator there is no such difference, but as the latitude of the place of observation increases, this difference increases. This is due to the fact that our planet is inclined at an angle of 23.3 degrees relative to the sun. In winter, it is low above the horizon and illuminates the earth only by sliding beams, which less heat the illuminated surface. This position of the rays causes their distribution over a larger surface, which reduces their intensity compared with the summer sheer drop. In addition, the presence of an acute angle during the passage of rays through the atmosphere, "lengthens" their path, causing them to lose more heat. This circumstance reduces the effects of solar radiation in the winter.
The sun is a star that is a source of heat and light for our planet. It "controls" the climate, the change of seasons and the state of the entire biosphere of the Earth. And only knowledge of the laws of this mighty impact will allow using this life-giving gift for the benefit of people's health.