Solar radiation or ionizing radiation from the sun. Total solar radiation

The Sun (astro. ☉) is the only star in the Solar System. Other objects of this system revolve around the Sun: planets and their satellites, dwarf planets and their satellites, asteroids, meteoroids, comets and cosmic dust.

Internal structure of the Sun

Our Sun is a huge luminous ball of gas, within which complex processes take place and, as a result, energy is continuously released. The interior volume of the Sun can be divided into several regions; the substance in them differs in its properties, and energy is distributed through different physical mechanisms. Let's get to know them, starting from the very center.

In the central part of the Sun there is a source of its energy, or, in figurative language, that “stove” that heats it and does not allow it to cool. This area is called the core. Under the weight of the outer layers, the matter inside the Sun is compressed, and the deeper, the stronger. Its density increases towards the center along with increasing pressure and temperature. In the core, where the temperature reaches 15 million Kelvin, energy is released.

This energy is released as a result of the fusion of atoms of light chemical elements into atoms of heavier ones. In the depths of the Sun, one helium atom is formed from four hydrogen atoms. It is this terrible energy that people have learned to release during an explosion. hydrogen bomb. There is hope that in the near future people will be able to learn to use it for peaceful purposes (in 2005, news feeds reported the start of construction of the first international fusion reactor in France).

The core has a radius of no more than a quarter of the total radius of the Sun. However, half of its volume is concentrated solar mass and almost all the energy that supports the glow of the Sun is released. But the energy of the hot core must somehow escape outward, to the surface of the Sun. There are various ways energy transfer depending on the physical conditions of the environment, namely: radiative transfer, convection and thermal conductivity. Thermal conductivity does not play a big role in energy processes in the Sun and stars, while radiative and convective transfers are very important.

Immediately around the nucleus, a zone of radiative energy transfer begins, where it spreads through the absorption and emission of a portion of light by the substance - quanta. Density, temperature and pressure decrease as you move away from the core, and energy flows in the same direction. Overall, this process is extremely slow. It takes many thousands of years for quanta to get from the center of the Sun to the photosphere: after all, when re-emitted, quanta constantly change direction, moving backward almost as often as forward.

Gamma quanta are born in the center of the Sun. Their energy is millions of times greater than the energy of visible light quanta, and their wavelength is very short. Along the way, quanta undergo amazing transformations. A separate quantum is first absorbed by some atom, but is immediately re-emitted again; Most often, in this case, not one previous quantum appears, but two or more. According to the law of conservation of energy, their total energy is conserved, and therefore the energy of each of them decreases. This is how quanta of lower and lower energies arise. Powerful gamma rays seem to be split into less energetic quanta - first X-ray, then ultraviolet and

finally visible and infrared rays. In the end greatest number energy the sun emits in visible light, and it is no coincidence that our eyes are sensitive to it.

As we have already said, it takes a very long time for a quantum to penetrate through the dense solar matter to the outside. So if the “stove” inside the Sun suddenly went out, we would only know about it millions of years later. On its way through the inner solar layers, the energy flow encounters a region where the opacity of the gas greatly increases. This is the convective zone of the Sun. Here energy is transferred not by radiation, but by convection.

What is convection?

When the liquid boils, it is stirred. Gas can behave the same way. Huge streams of hot gas rise upward, where they give off their heat environment, and the cooled solar gas descends. The solar matter appears to be boiling and stirring. The convective zone begins at approximately 0.7 radius from the center and extends almost to the most visible surface of the Sun (photosphere), where the transfer of the main energy flow again becomes radiant. However, due to inertia, hot flows from deeper, convective layers still penetrate here. The pattern of granulation on the surface of the Sun, well known to observers, is a visible manifestation of convection.

Convective zone of the Sun

The radioactive zone is about 2/3 of the internal diameter of the Sun, and the radius is about 140 thousand km. Moving away from the center, photons lose their energy under the influence of collision. This phenomenon is called the convection phenomenon. This is reminiscent of the process that occurs in a boiling kettle: energy coming from heating element, much more than the amount that is removed by conduction. Hot water, located close to the fire, rises, and the colder one goes down. This process is called convention. The meaning of convection is that denser gas is distributed over the surface, cools and again goes to the center. The mixing process in the convective zone of the Sun is carried out continuously. Looking through a telescope at the surface of the Sun, you can see its granular structure - granulations. It feels like it's made of granules! This is due to convection occurring beneath the photosphere.

Photosphere of the Sun

A thin layer (400 km) - the photosphere of the Sun, is located directly behind the convective zone and represents the “real solar surface” visible from Earth. Granules in the photosphere were first photographed by the Frenchman Janssen in 1885. The average granule has a size of 1000 km, moves at a speed of 1 km/sec and exists for approximately 15 minutes. Dark formations in the photosphere can be observed in the equatorial part, and then they shift. Strong magnetic fields are a distinctive feature of such spots. A dark color is obtained due to the lower temperature relative to the surrounding photosphere.

Chromosphere of the Sun

Chromosphere of the Sun (colored sphere) – dense layer (10,000 km) solar atmosphere, which is located just beyond the photosphere. The chromosphere is quite problematic to observe due to its close location to the photosphere. It is best seen when the Moon covers the photosphere, i.e. during solar eclipses.

Solar prominences are huge emissions of hydrogen, resembling long luminous filaments. The prominences rise to enormous distances, reaching the diameter of the Sun (1.4 mm km), move at a speed of about 300 km/sec, and the temperature reaches 10,000 degrees.

Solar corona

The solar corona is the outer and extended layers of the Sun's atmosphere, originating above the chromosphere. The length of the solar corona is very long and reaches values of several solar diameters. Scientists have not yet received a clear answer to the question of where exactly it ends.

The composition of the solar corona is a rarefied, highly ionized plasma. It contains heavy ions, electrons with a helium core, and protons. The temperature of the corona reaches from 1 to 2 million degrees K, relative to the surface of the Sun.

The solar wind is a continuous outflow of matter (plasma) from the outer shell of the solar atmosphere. It consists of protons, atomic nuclei and electrons. The speed of the solar wind can vary from 300 km/sec to 1500 km/sec, in accordance with the processes occurring on the Sun. The solar wind spreads throughout the solar system and, interacting with magnetic field Earth, calls various phenomena, one of which is the northern lights.

Radiation from the Sun

The sun emits its energy in all wavelengths, but in different ways. Approximately 44% of the radiation energy is in the visible part of the spectrum, and the maximum corresponds to the yellow-green color. About 48% of the energy lost by the Sun is carried away by near and far infrared rays. Gamma rays, X-rays, ultraviolet and radio radiation account for only about 8%.

The visible part of solar radiation, when studied using spectrum-analyzing instruments, turns out to be inhomogeneous - absorption lines first described by J. Fraunhofer in 1814 are observed in the spectrum. These lines arise when photons of certain wavelengths are absorbed by atoms of various chemical elements in the upper, relatively cold, layers of the Sun's atmosphere. Spectral analysis allows us to obtain information about the composition of the Sun, since a certain set of spectral lines exclusively characterizes chemical element. For example, using observations of the spectrum of the Sun, the discovery of helium was predicted, which was isolated later on Earth.

Types of radiation

During observations, scientists found that the Sun is a powerful source of radio emission. Radio waves penetrate into interplanetary space and are emitted by the chromosphere (centimeter waves) and the corona (decimeter and meter waves). Radio emission from the Sun has two components – constant and variable (bursts, “noise storms”). During strong solar flares, radio emission from the Sun increases thousands and even millions of times compared to radio emission from the quiet Sun. This radio emission is non-thermal in nature.

X-rays come mainly from upper layers chromosphere and corona. The radiation is especially strong during the years of maximum solar activity.

The sun emits not only light, heat and all other types electromagnetic radiation. It is also a source of a constant flow of particles - corpuscles. Neutrinos, electrons, protons, alpha particles, and heavier atomic nuclei all together make up the corpuscular radiation of the Sun. A significant part of this radiation is a more or less continuous outflow of plasma - the solar wind, which is a continuation of the outer layers of the solar atmosphere - the solar corona. Against the background of this constantly blowing plasma wind, individual regions on the Sun are sources of more directed, enhanced, so-called corpuscular flows. Most likely, they are associated with special regions of the solar corona - coronal holes, and also, possibly, with long-lived active regions on the Sun. Finally, with solar flares The most powerful short-term flows of particles, mainly electrons and protons, are associated. As a result of the most powerful flares, particles can acquire speeds that are a noticeable fraction of the speed of light. Particles with such high energies are called solar cosmic rays.

Solar corpuscular radiation has a strong influence on the Earth, and primarily on the upper layers of its atmosphere and magnetic field, causing many geophysical phenomena. The Earth's magnetosphere and atmosphere protect us from the harmful effects of solar radiation.

Solar radiation intensity

Having extremely high temperatures, the Sun is a very strong source of radiation. The visible range of solar radiation has the highest radiation intensity. At the same time, it also reaches the Earth large number invisible spectrum. Processes take place inside the Sun in which helium atoms are synthesized from hydrogen atoms. These processes are called nuclear fusion processes, they are accompanied by the release of huge amounts of energy. This energy causes the Sun to heat up to a temperature of 15 million degrees Celsius (in its inner part).

On the surface of the Sun (photosphere) the temperature reaches 5500 °C. On this surface, the Sun emits energy of 63 MW/m². Only a small part of this radiation reaches the surface of the Earth, which allows humanity to exist comfortably on our planet. The average radiation intensity on the Earth's atmosphere is approximately 1367 W/m². This value can fluctuate in the range of 5% due to the fact that, moving along an elliptical orbit, the Earth moves away from the Sun at different distances throughout the year. The value of 1367 W/m² is called the solar constant.

Solar energy on the surface of the Earth

The Earth's atmosphere does not allow all solar energy to pass through. The Earth's surface reaches no more than 1000 W/m2. Some of the energy is absorbed, some is reflected in the layers of the atmosphere and in the clouds. A large amount of radiation is scattered in the layers of the atmosphere, resulting in the formation of scattered radiation (diffuse). On the surface of the Earth, part of the radiation is also reflected and turns into scattered radiation. The sum of scattered and direct radiation is called total solar radiation. Scattered radiation can range from 20 to 60%.

The amount of energy reaching the Earth's surface is also affected by geographic latitude and time of year. The axis of our planet, passing through the poles, is tilted by 23.5° relative to its orbit around the Sun. Between March

until September sunlight more hits Northern Hemisphere, the rest of the time – Yuzhnoe. Therefore, the length of the day in summer and winter time different. The latitude of the area affects the duration daylight hours. The further north, the longer summer time and vice versa.

Evolution of the Sun

It is assumed that the Sun was born in a compressed gas and dust nebula. There are at least two theories as to what triggered the initial contraction of the nebula. According to one of them, it is assumed that one of the spiral arms of our galaxy passed through our region of space approximately 5 billion years ago. This could cause slight compression and lead to the formation of centers of gravity in the gas-dust cloud. Indeed, we now see quite a large number of young stars and glowing gas clouds along the spiral arms. Another theory suggests that somewhere nearby (on the scale of the Universe, of course) an ancient massive supernova exploded. Emerging shock wave could be strong enough to initiate star formation in “our” gas-dust nebula. This theory is supported by the fact that scientists studying meteorites have discovered quite a lot of elements that could have been formed during a supernova explosion.

Further, when such a colossal mass (2 * 1030 kg) was compressed under the influence of gravitational forces, it strongly heated itself with internal pressure to temperatures at which thermonuclear reactions could begin in its center. In the central part, the temperature on the Sun is 15,000,000K, and the pressure reaches hundreds of billions of atmospheres. This is how a newborn star was lit (not to be confused with new stars).

The Sun at the beginning of its life consisted mainly of hydrogen. It is hydrogen that turns into helium during thermonuclear reactions, releasing energy emitted by the Sun. The Sun belongs to a type of star called yellow dwarf. It is a main sequence star and belongs to the spectral class G2. The mass of a lone star quite clearly determines its fate. During its lifetime (~5 billion years), in the center of our star, where the temperature is quite high, about half of all the hydrogen there was burned. About the same amount of time, 5 billion years, the Sun has left to live in the form to which we are accustomed.

After the hydrogen in the center of the star runs out, the Sun will increase in size and become a red giant. This will have a dramatic impact on Earth: temperatures will rise, the oceans will boil, life will become impossible. Then, having exhausted the “fuel” completely and no longer having the strength to hold the outer layers of the red giant, our star will end its life as a white dwarf, delighting the unknown extraterrestrial astronomers of the future with a new planetary nebula, the shape of which may turn out to be very bizarre due to the influence of the planets.

Death of the Sun by time

In just 1.1 billion years, the star will increase its brightness by 10%, which will lead to strong heating of the Earth.
In 3.5 billion years, the brightness will increase by 40%. The oceans will begin to evaporate and all life on Earth will end.
After 5.4 billion years, the star's core will run out of fuel - hydrogen. The sun will begin to increase in size due to the rarefaction of the outer shell and heating of the core.
In 7.7 billion years, our star will turn into a red giant, because increase by 200 times because of this the planet Mercury will be absorbed.
At the end, after 7.9 billion years, the outer layers of the star will become so thin that they will disintegrate into a nebula, and in the center former Sun there will be a small object - a white dwarf. This is how our existence will end solar system. All building elements remaining after the collapse will not be lost; they will become the basis for the birth of new stars and planets.

The most common stars in the universe are red dwarfs. This is largely due to their low mass, which allows them to live for a very long time before becoming white dwarfs.
Almost all stars in the universe have the same chemical composition and the nuclear fusion reaction occurs in every star and is almost identical, determined only by the supply of fuel.
As we know, like a white dwarf, neutron stars are one of the final processes of stellar evolution, largely arising after a supernova explosion. Previously, it was often difficult to distinguish a white dwarf from a neutron star, but now scientists using telescopes have found differences in them. Neutron star gathers more light around itself and this is easy to see with infrared telescopes. Eighth place among interesting facts about the stars.
Due to its incredible mass, according to Einstein's general theory of relativity, a black hole is actually a bend in space such that everything within it gravitational field pushes towards him. The gravitational field of a black hole is so strong that not even light can escape it.
As far as we know, when a star runs out of fuel, the star can grow in size by more than 1000 times, then it turns into a white dwarf, and due to the speed of the reaction, it explodes. This reaction is better known as a supernova. Scientists suggest that in connection with this long process, such mysterious black holes are formed.
Many of the stars we see in the night sky can appear as just one glimpse of light. However, this is not always the case. Most of the stars we see in the sky are actually two star systems, or binary star systems. They are simply unimaginably far away and it seems to us that we see only one speck of light.
The stars that have the shortest lifespans are the most massive. They represent a high mass chemicals and typically burn their fuel much faster.
Despite the fact that sometimes it seems to us that the Sun and stars are twinkling, in fact this is not the case. The flickering effect is only the light from the star, which at this time passes through the Earth's atmosphere but has not yet reached our eyes. Third place among the most interesting facts about stars.
The distances involved in estimating how far away a star is are unimaginably huge. Let's consider an example: The closest star to earth is approximately 4.2 light years away, and to get to it, even on our fastest ship, will take about 70,000 years.
The coldest famous star, this is a brown dwarf "CFBDSIR 1458+10B" with a temperature of only about 100 °C. The hottest star known, it is a blue supergiant located in milky way called "Zeta Puppis" its temperature is more than 42,000 °C.

Heat sources. In the life of the atmosphere is of decisive importance thermal energy. The main source of this energy is the Sun. As for the thermal radiation of the Moon, planets and stars, it is so insignificant for the Earth that it practically cannot be taken into account. Significantly more thermal energy is provided by the internal heat of the Earth. According to geophysicists, the constant flow of heat from the depths of the Earth increases the temperature earth's surface at 0°,1. But such a heat influx is still so small that there is no need to take it into account either. Thus, the only source of thermal energy on the surface of the Earth can be considered only the Sun.

Solar radiation. The sun, which has a photosphere (radiating surface) temperature of about 6000°, radiates energy into space in all directions. Part of this energy in the form of a huge beam of parallel solar rays hits the Earth. Solar energy that reaches the surface of the Earth in the form of direct rays from the Sun is called direct solar radiation. But not all solar radiation directed at the Earth reaches the earth's surface, since sun rays passing through a thick layer of the atmosphere, they are partially absorbed by it, partially scattered by molecules and suspended air particles, and some are reflected by clouds. That part of solar energy that is dissipated in the atmosphere is called scattered radiation. Scattered solar radiation travels through the atmosphere and reaches the Earth's surface. We perceive this type of radiation as uniform daylight, when the Sun is completely covered by clouds or has just disappeared below the horizon.

Direct and diffuse solar radiation, having reached the Earth's surface, is not completely absorbed by it. Part of the solar radiation is reflected from the earth's surface back into the atmosphere and is found there in the form of a stream of rays, the so-called reflected solar radiation.

The composition of solar radiation is very complex, which is associated with very high temperature radiating surface of the Sun. Conventionally, according to wavelength, the spectrum of solar radiation is divided into three parts: ultraviolet (η<0,4<μ видимую глазом (η from 0.4μ to 0.76μ) and the infrared part (η >0.76μ). In addition to the temperature of the solar photosphere, the composition of solar radiation at the earth's surface is also influenced by the absorption and scattering of part of the sun's rays as they pass through the air shell of the Earth. In this regard, the composition of solar radiation at the upper boundary of the atmosphere and at the surface of the Earth will be different. Based on theoretical calculations and observations, it has been established that at the boundary of the atmosphere, ultraviolet radiation accounts for 5%, visible rays - 52% and infrared - 43%. At the earth's surface (at a solar altitude of 40°), ultraviolet rays account for only 1%, visible rays account for 40%, and infrared rays account for 59%.

Solar radiation intensity. The intensity of direct solar radiation is understood as the amount of heat in calories received per minute. from the radiant energy of the Sun's surface in 1 cm 2, located perpendicular to the sun's rays.

To measure the intensity of direct solar radiation, special instruments are used - actinometers and pyrheliometers; The amount of scattered radiation is determined by a pyranometer. Automatic registration of the duration of solar radiation is carried out by actinographs and heliographs. The spectral intensity of solar radiation is determined by a spectrobolograph.

At the boundary of the atmosphere, where the absorbing and scattering effects of the Earth's air shell are excluded, the intensity of direct solar radiation is approximately 2 feces by 1 cm 2 surfaces in 1 min. This quantity is called solar constant. Solar radiation intensity in 2 feces by 1 cm 2 in 1 min. provides such a large amount of heat during the year that it would be enough to melt a layer of ice 35 m thick if such a layer covered the entire earth's surface.

Numerous measurements of the intensity of solar radiation give reason to believe that the amount of solar energy arriving at the upper boundary of the Earth's atmosphere experiences fluctuations of several percent. Oscillations are periodic and non-periodic, apparently associated with processes occurring on the Sun itself.

In addition, some change in the intensity of solar radiation occurs during the year due to the fact that the Earth, in its annual rotation, moves not in a circle, but in an ellipse, at one of the foci of which the Sun is located. In this regard, the distance from the Earth to the Sun changes and, consequently, the intensity of solar radiation fluctuates. The greatest intensity is observed around January 3, when the Earth is closest to the Sun, and the lowest around July 5, when the Earth is at its maximum distance from the Sun.

For this reason, the fluctuations in the intensity of solar radiation are very small and can only be of theoretical interest. (The amount of energy at maximum distance is related to the amount of energy at minimum distance as 100:107, i.e. the difference is completely negligible.)

Conditions of irradiation of the surface of the globe. The spherical shape of the Earth alone leads to the fact that the radiant energy of the Sun is distributed very unevenly on the earth's surface. So, on the days of the spring and autumn equinox (March 21 and September 23), only at the equator at noon the angle of incidence of the rays will be 90° (Fig. 30), and as it approaches the poles it will decrease from 90 to 0°. Thus,

if at the equator the amount of radiation received is taken as 1, then at the 60th parallel it will be expressed as 0.5, and at the pole it will be equal to 0.

The globe, in addition, has a daily and annual movement, and the earth's axis is inclined to the orbital plane by 66°.5. Due to this inclination, an angle of 23°30 is formed between the equatorial plane and the orbital plane. This circumstance leads to the fact that the angles of incidence of the sun's rays for the same latitudes will vary within 47° (23.5 + 23.5) .

Depending on the time of year, not only the angle of incidence of the rays changes, but also the duration of illumination. If in tropical countries the length of day and night is approximately the same at all times of the year, then in polar countries, on the contrary, it is very different. So, for example, at 70° N. w. in summer the Sun does not set for 65 days at 80° N. sh. - 134, and at the pole -186. Because of this, radiation at the North Pole on the day of the summer solstice (June 22) is 36% greater than at the equator. As for the entire summer half of the year, the total amount of heat and light received by the pole is only 17% less than at the equator. Thus, in the summer in polar countries, the duration of illumination largely compensates for the lack of radiation that is a consequence of the small angle of incidence of the rays. In the winter half of the year, the picture is completely different: the amount of radiation at the same North Pole will be equal to 0. As a result, over the year the average amount of radiation at the pole is 2.4 less than at the equator. From all that has been said, it follows that the amount of solar energy that the Earth receives through radiation is determined by the angle of incidence of the rays and the duration of irradiation.

In the absence of an atmosphere at different latitudes, the earth's surface would receive the following amount of heat per day, expressed in calories per 1 cm 2(see table on page 92).

The distribution of radiation over the earth's surface given in the table is usually called solar climate. We repeat that we have such a distribution of radiation only at the upper boundary of the atmosphere.

Weakening of solar radiation in the atmosphere. So far we have talked about the conditions for the distribution of solar heat over the earth's surface, without taking into account the atmosphere. Meanwhile, the atmosphere in this case is of great importance. Solar radiation, passing through the atmosphere, experiences dispersion and, in addition, absorption. Both of these processes together attenuate solar radiation to a significant extent.

The sun's rays, passing through the atmosphere, first experience scattering (diffusion). Scattering is created by the fact that light rays, refracted and reflected from air molecules and particles of solid and liquid bodies in the air, deviate from the straight path To really "dissipate".

Scattering greatly attenuates solar radiation. With an increase in the amount of water vapor and especially dust particles, the dispersion increases and the radiation is weakened. In large cities and desert areas, where the dust content of the air is greatest, dispersion weakens the strength of radiation by 30-45%. Thanks to scattering, daylight is obtained that illuminates objects, even if the sun's rays do not directly fall on them. Scattering also determines the color of the sky.

Let us now dwell on the ability of the atmosphere to absorb radiant energy from the Sun. The main gases that make up the atmosphere absorb relatively little radiant energy. Impurities (water vapor, ozone, carbon dioxide and dust), on the contrary, have a high absorption capacity.

In the troposphere, the most significant impurity is water vapor. They absorb especially strongly infrared (long-wavelength), i.e., predominantly thermal rays. And the more water vapor in the atmosphere, the naturally more and. absorption. The amount of water vapor in the atmosphere is subject to large changes. Under natural conditions, it varies from 0.01 to 4% (by volume).

Ozone has a very high absorption capacity. A significant admixture of ozone, as already mentioned, is located in the lower layers of the stratosphere (above the tropopause). Ozone absorbs ultraviolet (short-wave) rays almost completely.

Carbon dioxide also has a high absorption capacity. It absorbs mainly long-wave, i.e., predominantly thermal rays.

Dust in the air also absorbs some solar radiation. When heated by the sun's rays, it can significantly increase the air temperature.

Of the total amount of solar energy coming to the Earth, the atmosphere absorbs only about 15%.

The attenuation of solar radiation by scattering and absorption by the atmosphere is very different for different latitudes of the Earth. This difference depends primarily on the angle of incidence of the rays. At the zenith position of the Sun, the rays, falling vertically, cross the atmosphere along the shortest path. As the angle of incidence decreases, the path of the rays lengthens and the attenuation of solar radiation becomes more significant. The latter is clearly visible from the drawing (Fig. 31) and the attached table (in the table, the path of the sun's ray at the zenith position of the Sun is taken as one).

Depending on the angle of incidence of the rays, not only the number of rays changes, but also their quality. During the period when the Sun is at its zenith (above the head), ultraviolet rays account for 4%,

visible - 44% and infrared - 52%. When the Sun is positioned near the horizon, there are no ultraviolet rays at all, visible 28% and infrared 72%.

The complexity of the atmosphere's influence on solar radiation is further aggravated by the fact that its transmission capacity varies greatly depending on the time of year and weather conditions. So, if the sky remained cloudless all the time, then the annual course of the influx of solar radiation at various latitudes could be expressed graphically as follows (Fig. 32). The drawing clearly shows that with a cloudless sky in Moscow in May, June and July, the heat more would be received from solar radiation than at the equator. Similarly, in the second half of May, June and the first half of July, more heat would be received at the North Pole than at the equator and in Moscow. We repeat that this would be the case with a cloudless sky. But in reality this does not work, because cloudiness significantly weakens solar radiation. Let's give an example shown on the graph (Fig. 33). The graph shows how much solar radiation does not reach the Earth's surface: a significant part of it is delayed by the atmosphere and clouds.

However, it must be said that the heat absorbed by the clouds partly goes to warm the atmosphere, and partly indirectly reaches the earth's surface.

Daily and annual variations in solar intensitylight radiation. The intensity of direct solar radiation at the Earth's surface depends on the height of the Sun above the horizon and on the state of the atmosphere (its dustiness). If. If the transparency of the atmosphere was constant throughout the day, then the maximum intensity of solar radiation would be observed at noon, and the minimum at sunrise and sunset. In this case, the graph of the daily intensity of solar radiation would be symmetrical relative to half a day.

The content of dust, water vapor and other impurities in the atmosphere is constantly changing. In this regard, the transparency of the air changes and the symmetry of the solar radiation intensity graph is disrupted. Often, especially in summer, at midday, when the earth's surface is heated intensely, powerful upward air currents arise, and the amount of water vapor and dust in the atmosphere increases. This results in a significant reduction in solar radiation at midday; The maximum intensity of radiation in this case is observed in the pre-noon or afternoon hours. The annual variation in the intensity of solar radiation is also associated with changes in the height of the Sun above the horizon throughout the year and with the state of transparency of the atmosphere in different seasons. In the countries of the northern hemisphere, the highest height of the Sun above the horizon occurs in the month of June. But at the same time, the greatest dustiness of the atmosphere is observed. Therefore, the maximum intensity usually occurs not in the middle of summer, but in the spring months, when the Sun rises quite high* above the horizon, and the atmosphere after winter remains relatively clear. To illustrate the annual variation of solar radiation intensity in the northern hemisphere, we present data on monthly average midday radiation intensity values in Pavlovsk.

The amount of heat from solar radiation. During the day, the Earth's surface continuously receives heat from direct and diffuse solar radiation or only from diffuse radiation (in cloudy weather). The daily amount of heat is determined based on actinometric observations: by taking into account the amount of direct and diffuse radiation received on the earth's surface. Having determined the amount of heat for each day, the amount of heat received by the earth's surface per month or per year is calculated.

The daily amount of heat received by the earth's surface from solar radiation depends on the intensity of radiation and the duration of its action during the day. In this regard, the minimum heat influx occurs in winter, and the maximum in summer. In the geographic distribution of total radiation around the globe, its increase is observed with decreasing latitude. This position is confirmed by the following table.

The role of direct and diffuse radiation in the annual amount of heat received by the earth's surface at different latitudes of the globe is different. At high latitudes, the annual amount of heat is dominated by scattered radiation. With decreasing latitude, direct solar radiation becomes dominant. For example, in Tikhaya Bay, diffuse solar radiation provides 70% of the annual amount of heat, and direct radiation only 30%. In Tashkent, on the contrary, direct solar radiation provides 70%, scattered only 30%.

Reflectivity of the Earth. Albedo. As already indicated, the Earth's surface absorbs only part of the solar energy that reaches it in the form of direct and diffuse radiation. The other part is reflected into the atmosphere. The ratio of the amount of solar radiation reflected by a given surface to the amount of radiant energy flux incident on this surface is called albedo. Albedo is expressed as a percentage and characterizes the reflectivity of a given surface area.

Albedo depends on the nature of the surface (soil properties, presence of snow, vegetation, water, etc.) and on the angle of incidence of the Sun's rays on the Earth's surface. So, for example, if the rays fall on the earth's surface at an angle of 45°, then:

From the above examples it is clear that the reflectivity of different objects is not the same. It is greatest near snow and least near water. However, the examples we have taken relate only to those cases when the height of the Sun above the horizon is 45°. As this angle decreases, the reflectivity increases. So, for example, at a solar altitude of 90°, water reflects only 2%, at 50° - 4%, at 20° - 12%, at 5° - 35-70% (depending on the state of the water surface).

On average, with a cloudless sky, the surface of the globe reflects 8% of solar radiation. In addition, 9% is reflected by the atmosphere. Thus, the globe as a whole, with a cloudless sky, reflects 17% of the radiant energy of the Sun falling on it. If the sky is covered with clouds, then 78% of the radiation is reflected from them. If we take natural conditions, based on the ratio between a cloudless sky and a sky covered with clouds, which is observed in reality, then the reflectivity of the Earth as a whole is equal to 43%.

Terrestrial and atmospheric radiation. The Earth, receiving solar energy, heats up and itself becomes a source of heat radiation into space. However, the rays emitted by the earth's surface are very different from the sun's rays. The earth emits only long-wave (λ 8-14 μ) invisible infrared (thermal) rays. The energy emitted by the earth's surface is called terrestrial radiation. Radiation from the Earth occurs... day and night. The higher the temperature of the emitting body, the greater the radiation intensity. Terrestrial radiation is determined in the same units as solar radiation, i.e. in calories from 1 cm 2 surfaces in 1 min. Observations have shown that the amount of terrestrial radiation is small. Usually it reaches 15-18 hundredths of a calorie. But, acting continuously, it can give a significant thermal effect.

The strongest terrestrial radiation is obtained with a cloudless sky and good transparency of the atmosphere. Cloud cover (especially low clouds) significantly reduces terrestrial radiation and often brings it to zero. Here we can say that the atmosphere, together with the clouds, is a good “blanket” that protects the Earth from excessive cooling. Parts of the atmosphere, like areas of the earth's surface, emit energy according to their temperature. This energy is called atmospheric radiation. The intensity of atmospheric radiation depends on the temperature of the radiating part of the atmosphere, as well as on the amount of water vapor and carbon dioxide contained in the air. Atmospheric radiation belongs to the long-wave group. It spreads in the atmosphere in all directions; a certain amount of it reaches the earth's surface and is absorbed by it, the other part goes into interplanetary space.

ABOUT the arrival and consumption of solar energy on Earth. The earth's surface, on the one hand, receives solar energy in the form of direct and diffuse radiation, and on the other hand, loses part of this energy in the form of terrestrial radiation. As a result of the arrival and consumption of solar energy, some result is obtained. In some cases, this result can be positive, in others negative. Let us give examples of both.

January 8. The day is cloudless. On 1 cm 2 earth's surface received in 20 days feces direct solar radiation and 12 feces scattered radiation; in total, this gives 32 cal. During the same time, due to radiation 1 cm? earth's surface lost 202 cal. As a result, in accounting language, the balance sheet has a loss of 170 feces(negative balance).

July 6. The sky is almost cloudless. 630 received from direct solar radiation feces, from scattered radiation 46 cal. In total, therefore, the earth's surface received 1 cm 2 676 cal. 173 lost through terrestrial radiation cal. The balance sheet shows a profit of 503 feces(balance is positive).

From the examples given, among other things, it is completely clear why temperate latitudes are cold in winter and warm in summer.

Use of solar radiation for technical and domestic purposes. Solar radiation is an inexhaustible natural source of energy. The amount of solar energy on Earth can be judged by this example: if, for example, we use the heat of solar radiation falling on only 1/10 of the area of the USSR, then we can obtain energy equal to the work of 30 thousand Dnieper hydroelectric stations.

People have long sought to use the free energy of solar radiation for their needs. To date, many different solar power plants have been created that operate using solar radiation and are widely used in industry and to meet the domestic needs of the population. In the southern regions of the USSR, solar water heaters, boilers, salt water desalination plants, solar dryers (for drying fruits), kitchens, bathhouses, greenhouses, and devices for medicinal purposes operate on the basis of the widespread use of solar radiation in industry and public utilities. Solar radiation is widely used in resorts to treat and improve people's health.

When talking about the effect of the sun on the human body, it is impossible to accurately determine whether it is harmful or beneficial. Sun rays are like kilocalories from food. Their deficiency leads to exhaustion, and in excess they cause obesity. So it is in this situation. In moderate amounts, solar radiation has a beneficial effect on the body, while excess ultraviolet radiation provokes burns and the development of numerous diseases. Let's take a closer look.

Solar radiation: general effects on the body

Solar radiation is a combination of ultraviolet and infrared waves. Each of these components has its own effect on the body.

Effect of infrared radiation:

The main feature of infrared rays is the thermal effect they create. Warming up the body helps to dilate blood vessels and normalize blood circulation.
Warming has a relaxing effect on the muscles, providing a slight anti-inflammatory and analgesic effect.
Under the influence of heat, metabolism increases and the processes of assimilation of biologically active components are normalized.
Infrared radiation from the sun stimulates the functioning of the brain and visual apparatus.
Thanks to solar radiation, the body's biological rhythms are synchronized, sleep and wakefulness modes are triggered.
Treatment with solar heat improves the condition of the skin, eliminating acne.
Warm light lifts the mood and improves a person’s emotional background.
And according to recent studies, it also improves sperm quality in men.

Despite all the debate about the negative effects of ultraviolet radiation on the body, its lack can lead to serious health problems. This is one of the vital factors of existence. And under conditions of ultraviolet deficiency, the following changes begin to occur in the body:

First of all, the immune system weakens. This is caused by a violation of the absorption of vitamins and minerals, a failure of metabolism at the cellular level.
There is a tendency to develop new or worsen chronic diseases, most often occurring with complications.
There is lethargy, chronic fatigue syndrome, and the level of performance decreases.
Lack of ultraviolet radiation for children interferes with the production of vitamin D and provokes a decrease in growth rates.

However, you need to understand that excessive solar activity will not benefit the body!

Contraindications to sunbathing

Despite all the benefits of sunlight for the body, not everyone can afford to enjoy the warm rays. Contraindications include:

acute inflammatory processes;
tumors, regardless of their location;
progressive tuberculosis;
angina pectoris, ischemic disease;
endocrine pathologies;
damage to the nervous system;
dysfunction of the thyroid gland and adrenal glands;
diabetes mellitus;
mastopathy;
uterine fibroids;
pregnancy;
recovery period after surgery.

In all cases, active radiation will aggravate the course of the disease, provoking the development of new complications.

Elderly people and infants should not get carried away with the sun. For these categories of the population, treatment with sunlight in the shade is indicated. The required dose of safe heat will be enough there.

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Negative effects of the sun

The time of exposure to infrared and ultraviolet waves should be strictly limited. Excessive amounts of solar radiation:

can provoke a deterioration in the general condition of the body (so-called heat stroke due to overheating);
negatively affects the skin, causing permanent changes;
impairs vision;
provokes hormonal imbalances in the body;
may provoke the development of allergic reactions.

So lying on the beach for hours during periods of maximum solar activity causes enormous damage to the body.

To get the necessary portion of light, a twenty-minute walk on a sunny day is enough.

The effect of the sun on the skin

Excessive amounts of solar radiation lead to serious skin problems. In the short term, you risk getting a burn or dermatitis. This is the smallest problem you may encounter when tanning on a hot day. If a similar situation is repeated with enviable regularity, the sun's radiation will become an impetus for the formation of malignant formations on the skin, melanomas.

In addition, exposure to ultraviolet radiation dries out the skin, making it thinner and more sensitive. And constant exposure to direct rays accelerates the aging process, causing the appearance of early wrinkles.

In order to protect yourself from the negative effects of solar radiation, it is enough to follow simple safety measures:

In the summer, be sure to use sunscreen? Apply it to all exposed areas of the body, including the face, arms, legs and décolleté. The SPF icon on the packaging is the very same ultraviolet protection. And its degree will depend on the number indicated next to the abbreviation. When going to the store, cosmetics with an SPF level of 15 or SPF 20 are suitable. If you plan to spend time on the beach, use special products with higher levels. A cream with maximum protection SPF 50 is suitable for children's skin.
If you need to stay outside for a long time at maximum intensity of solar radiation, wear clothes made of light fabrics with long sleeves. Be sure to wear a wide-brimmed hat to hide your delicate facial skin.
Control the duration of sunbathing. Recommended time is 15-20 minutes. If you stay outside for a longer period of time, try to hide from direct sunlight in the shade of trees.

And remember that in the summer, solar radiation affects the skin at any time of the day, with the exception of night hours. You may not feel any noticeable warmth from infrared waves, but ultraviolet light remains at a high level of activity both in the morning and in the afternoon.

Negative effects on vision

The effect of sunlight on the visual apparatus is enormous. After all, thanks to light rays we receive information about the world around us. Artificial lighting, to some extent, can become an alternative to natural light, but reading and writing with a lamp increases eye strain.

Speaking about the negative impact of sunlight on humans and vision, we mean eye damage from prolonged exposure to the sun without sunglasses.

Some of the unpleasant sensations that you may encounter include cutting pain in the eyes, their redness, and photophobia. The most serious damage is a retinal burn.. Dry eyelid skin and the formation of fine wrinkles are also possible.

Wear sunglasses. When purchasing, first of all pay attention to the degree of protection. Fashion models often slightly shade the light, but do not prevent the penetration of ultraviolet radiation. Therefore, it is recommended to put aside bright frames and opt for high-quality lenses.
Make sure that direct rays do not hit your face. Stay in the shade and wear a hat, cap or other headdress with a visor.
Don't look at the sun. If you do not experience discomfort, this does not mean that this idea is safe. Even the winter sun has enough activity to cause vision problems.

Is there a safe time of year?

The use of solar radiation as a healing procedure is a common practice. Both ultraviolet and heat are considered strong irritants. And the abuse of these benefits can cause serious problems.

Tanning is the production of melanin. To be more precise, it is a protective reaction of the skin to an irritant.

Is sun radiation dangerous at any time of the year? It is difficult to give a definite answer to this question. Everything will depend not so much on the time of year, but on the geographical location. Thus, in mid-latitudes, solar radiation activity increases by 25-35% in the summer. Therefore, recommendations regarding staying outside on a clear day apply only to hot weather. In winter, residents of these regions are not threatened by ultraviolet radiation.

But residents of the equator face direct sunlight all year round. Therefore, the likelihood of negative effects on the body is present both in summer and winter. The inhabitants of northern latitudes are luckier in this regard. Indeed, with distance from the equator, the angle of incidence of the sun's rays on the earth changes, and with it the radiation activity. The length of the thermal wave increases, and at the same time the amount of heat (energy losses) decreases. Hence, it is winter all year round, since the surface of the earth does not have enough heat to warm it up.

Solar radiation is our body's friend. But you shouldn't abuse this friendship. Otherwise, the consequences can be very serious. Just enjoy the warmth without forgetting about safety precautions.

Dazhbog among the Slavs, Apollo among the ancient Greeks, Mithra among the Indo-Iranians, Amon Ra among the ancient Egyptians, Tonatiuh among the Aztecs - in ancient pantheism people called the Sun God with these names.

Since ancient times, people have understood how important the Sun is for life on Earth and deified it.

The luminosity of the Sun is enormous and amounts to 3.85x10 23 kW. Solar energy acting on an area of just 1 m 2 is capable of charging a 1.4 kW engine.

The source of energy is the thermonuclear reaction taking place in the core of the star.

The 4 He formed in this case constitutes almost (0.01%) all the helium of the earth.

The star of our system emits electromagnetic and corpuscular radiation. From the outside of the Sun's corona, the solar wind, consisting of protons, electrons and α-particles, “blows” into outer space. With the solar wind, 2-3x10 -14 masses of the star are lost annually. Magnetic storms and aurora are associated with corpuscular radiation.

Electromagnetic radiation (solar radiation) reaches the surface of our planet in the form of direct and scattered rays. Its spectral range is:

ultraviolet radiation;
X-rays;
γ-rays.

The short-wave part accounts for only 7% of the energy. Visible light makes up 48% of the sun's radiation energy. It is mainly composed of blue-green radiation spectrum, 45% is infrared radiation and only a small part is represented by radio radiation.

Ultraviolet radiation, depending on the wavelength, is divided into:

Most of the long wavelength ultraviolet radiation reaches the earth's surface. The amount of UV-B energy reaching the surface of the planet depends on the state of the ozone layer. UV-C is almost completely absorbed by the ozone layer and atmospheric gases. Back in 1994, WHO and WMO proposed introducing an ultraviolet index (UV, W/m2).

The visible part of the light is not absorbed by the atmosphere, but waves of some spectrum are scattered. Infrared color or mid-wave thermal energy is mainly absorbed by water vapor and carbon dioxide. The source of the long-wave spectrum is the earth's surface.

All of the above ranges are of great importance for life on Earth. A significant portion of solar radiation does not reach the Earth's surface. The following types of radiation are recorded at the surface of the planet:

1% ultraviolet;
40% optical;
59% infrared.

Types of radiation

The intensity of solar radiation depends on:

latitude;
season;
time of day;
atmospheric conditions;
features and relief of the earth's surface.

In different parts of the Earth, solar radiation affects living organisms differently.

Photobiological processes occurring under the influence of light energy, depending on their role, can be divided into the following groups:

synthesis of biologically active substances (photosynthesis);
photobiological processes that help navigate in space and help obtain information (phototaxis, vision, photoperiodism);
damaging effects (mutations, carcinogenic processes, destructive effects on bioactive substances).

Insolation calculation

Light radiation has a stimulating effect on photobiological processes in the body - the synthesis of vitamins, pigments, cellular photostimulation. The sensitizing effect of sunlight is currently being studied.

Ultraviolet radiation, affecting the skin of the human body, stimulates the synthesis of vitamins D, B4 and proteins, which are regulators of many physiological processes. Ultraviolet radiation affects:

metabolic processes;
immune system;
nervous system;
endocrine system.

The sensitizing effect of ultraviolet radiation depends on the wavelength:

The stimulating effect of sunlight is expressed in increasing specific and nonspecific immunity. For example, in children who are exposed to moderate natural UV radiation, the number of colds is reduced by 1/3. At the same time, the effectiveness of treatment increases, there are no complications, and the period of the disease is reduced.

The bactericidal properties of the short-wave spectrum of UV radiation are used in medicine, the food industry, and pharmaceutical production for the disinfection of environments, air and products. Ultraviolet radiation destroys the tuberculosis bacillus within a few minutes, staphylococcus in 25 minutes, and the causative agent of typhoid fever in 60 minutes.

Nonspecific immunity, in response to ultraviolet irradiation, responds with an increase in compliment titers and agglutination, and an increase in the activity of phagocytes. But increased UV radiation causes pathological changes in the body:

skin cancer;
solar erythema;
damage to the immune system, which is expressed in the appearance of freckles, nevi, solar lentigines.

Visible sunlight:

makes it possible to obtain 80% of the information using a visual analyzer;
accelerates metabolic processes;
improves mood and overall well-being;
warms;
affects the state of the central nervous system;
determines circadian rhythms.

The degree of exposure to infrared radiation depends on the wavelength:

long-wave - has weak penetrating ability and is largely absorbed by the surface of the skin, causing erythema;
short-wave – penetrates deep into the body, providing a vasodilator, analgesic, and anti-inflammatory effect.

In addition to its impact on living organisms, solar radiation is of great importance in shaping the Earth's climate.

The importance of solar radiation for climate

The sun is the main source of heat that shapes the earth's climate. In the early stages of the Earth's development, the Sun emitted 30% less heat than it does now. But thanks to the saturation of the atmosphere with gases and volcanic dust, the climate on Earth was humid and warm.

There is a cyclicity in the intensity of insolation, which causes warming and cooling of the climate. Cyclicity explains the Little Ice Age, which began in the 14th-19th centuries. and climate warming observed in the period 1900-1950.

In the history of the planet, there is a periodic change in the axis tilt and orbital eccentricity, which changes the redistribution of solar radiation on the surface and affects the climate. For example, these changes are reflected in the increase and decrease in the area of the Sahara Desert.

Interglacial periods last about 10,000 years. The Earth is currently in an interglacial period called the Heliocene. Thanks to early human agricultural activities, this period lasted longer than expected.

Scientists have described 35-45 year cycles of climate change, during which a dry and warm climate changes to a cool and humid one. They affect the filling of inland water bodies, the level of the World Ocean, and changes in glaciation in the Arctic.

Solar radiation is distributed differently. For example, in the middle latitudes in the period from 1984 to 2008, there was an increase in total and direct solar radiation and a decrease in scattered radiation. Changes in intensity are also observed throughout the year. Thus, the peak occurs in May-August, and the minimum occurs in the winter.

Since the height of the Sun and the duration of daylight hours in summer are greater, this period accounts for up to 50% of the total annual radiation. And in the period from November to February - only 5%.

The amount of solar radiation falling on a certain surface of the Earth affects important climatic indicators:

temperature;
humidity;
atmospheric pressure;
cloudiness;
precipitation;
wind speed.

An increase in solar radiation increases temperature and atmospheric pressure; other characteristics are in the opposite ratio. Scientists have found that the levels of total and direct radiation from the Sun have the greatest impact on climate.

Solar protection measures

Solar radiation has a sensitizing and damaging effect on humans in the form of heat and sunstroke, and the negative effects of radiation on the skin. Nowadays, a large number of celebrities have joined the anti-tanning movement.

Angelina Jolie, for example, says that she does not want to sacrifice several years of her life for two weeks of tanning.

To protect yourself from solar radiation, you must:

sunbathing in the morning and evening hours is the safest time;
use sunglasses;
during the period of active sun:

cover the head and open areas of the body;
use sunscreen with a UV filter;
purchase special clothing;
protect yourself with a wide-brimmed hat or sun umbrella;
observe drinking regime;
avoid intense physical activity.

When used wisely, solar radiation has a beneficial effect on the human body.

The sun is a source of warmth and light, giving strength and health. However, its impact is not always positive. A lack of energy or an excess of it can disrupt the natural processes of life and provoke various problems. Many are sure that tanned skin looks much more beautiful than pale skin, but if you spend a long time under direct rays, you can get a severe burn. Solar radiation is a stream of incoming energy distributed in the form of electromagnetic waves passing through the atmosphere. It is measured by the power of the energy it transfers per unit surface area (watt/m2). Knowing how the sun affects a person, you can prevent its negative effects.

What is solar radiation

Many books have been written about the Sun and its energy. The sun is the main source of energy for all physical and geographical phenomena on Earth. One two-billionth part of light penetrates into the upper layers of the planet’s atmosphere, while most of it settles in cosmic space.

Rays of light are the primary sources of other types of energy. When they fall on the surface of the earth and into water, they form into heat and affect climatic conditions and weather.

The degree to which a person is exposed to light rays depends on the level of radiation, as well as the period spent under the sun. People use many types of waves to their advantage, using x-rays, infrared rays, and ultraviolet. However, solar waves in their pure form in large quantities can negatively affect human health.

The amount of radiation depends on:

position of the Sun. The greatest amount of radiation occurs in plains and deserts, where the solstice is quite high and the weather is cloudless. The polar regions receive a minimal amount of light, since clouds absorb a significant part of the light flux;
length of the day. The closer to the equator, the longer the day. This is where people get the most heat;
atmospheric properties: cloudiness and humidity. At the equator there is increased cloudiness and humidity, which is an obstacle to the passage of light. That is why the amount of light flux there is less than in tropical zones.

Distribution

The distribution of sunlight over the earth's surface is uneven and depends on:

density and humidity of the atmosphere. The larger they are, the lower the radiation exposure;
geographic latitude of the area. The amount of light received increases from the poles to the equator;
Earth movements. The amount of radiation varies depending on the time of year;
characteristics of the earth's surface. A large amount of light is reflected in light-colored surfaces, such as snow. Chernozem reflects light energy most poorly.

Due to the extent of its territory, Russia's radiation levels vary significantly. Solar irradiation in the northern regions is approximately the same - 810 kWh/m2 for 365 days, in the southern regions - more than 4100 kWh/m2.

The length of the hours during which the sun shines is also important.. These indicators vary in different regions, which is influenced not only by geographic latitude, but also by the presence of mountains. The map of solar radiation in Russia clearly shows that in some regions it is not advisable to install power supply lines, since natural light is quite capable of meeting the residents’ needs for electricity and heat.

Species

Light streams reach the Earth in different ways. The types of solar radiation depend on this:

The rays emanating from the sun are called direct radiation. Their strength depends on the height of the sun above the horizon. The maximum level is observed at 12 noon, the minimum - in the morning and evening. In addition, the intensity of the impact is related to the time of year: the greatest occurs in summer, the least in winter. It is characteristic that in the mountains the level of radiation is higher than on flat surfaces. Dirty air also reduces direct light fluxes. The lower the sun is above the horizon, the less ultraviolet radiation there is.
Reflected radiation is radiation that is reflected by water or the surface of the earth.
Scattered solar radiation is formed when the light flux is scattered. The blue color of the sky in cloudless weather depends on it.

Absorbed solar radiation depends on the reflectivity of the earth's surface - albedo.

The spectral composition of the radiation is diverse:

colored or visible rays provide illumination and are of great importance in the life of plants;
ultraviolet radiation should penetrate the human body moderately, since its excess or deficiency can cause harm;
Infrared irradiation gives a feeling of warmth and affects the growth of vegetation.

Total solar radiation is direct and scattered rays penetrating the earth. In the absence of clouds, around 12 noon, as well as in the summer, it reaches its maximum.

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How does the impact occur?

Electromagnetic waves are made up of different parts. There are invisible, infrared and visible, ultraviolet rays. It is characteristic that radiation flows have different energy structures and affect people differently.

Light flux can have a beneficial, healing effect on the condition of the human body. Passing through the visual organs, light regulates metabolism, sleep patterns, and affects a person’s overall well-being. In addition, light energy can cause a feeling of warmth. When the skin is irradiated, photochemical reactions occur in the body that promote proper metabolism.

Ultraviolet has a high biological ability, having a wavelength from 290 to 315 nm. These waves synthesize vitamin D in the body and are also capable of destroying the tuberculosis virus in a few minutes, staphylococcus - within a quarter of an hour, and typhoid bacilli - in 1 hour.

It is characteristic that cloudless weather reduces the duration of emerging epidemics of influenza and other diseases, for example, diphtheria, which can be transmitted by airborne droplets.

The natural forces of the body protect a person from sudden atmospheric fluctuations: air temperature, humidity, pressure. However, sometimes such protection is weakened, which, under the influence of strong humidity together with elevated temperature, leads to heat stroke.

The impact of radiation depends on the degree of its penetration into the body. The longer the waves, the stronger the radiation force. Infrared waves can penetrate up to 23 cm under the skin, visible streams - up to 1 cm, ultraviolet - up to 0.5-1 mm.

People receive all types of rays during the activity of the sun, when they are in open spaces. Light waves allow a person to adapt to the world, which is why to ensure comfortable well-being in the premises it is necessary to create conditions for an optimal level of lighting.

Impact on humans

The influence of solar radiation on human health is determined by various factors. The place of residence of a person, the climate, as well as the amount of time spent under direct rays matter.

With a lack of sun, residents of the Far North, as well as people whose activities involve working underground, such as miners, experience various dysfunctions, decreased bone strength, and nervous disorders.

Children who do not receive enough light suffer from rickets more often than others. In addition, they are more susceptible to dental diseases, and also have a longer course of tuberculosis.

However, too much exposure to light waves without a periodic change of day and night can have detrimental effects on health. For example, residents of the Arctic often suffer from irritability, fatigue, insomnia, depression, and decreased ability to work.

Radiation in the Russian Federation is less active than, for example, in Australia.

Thus, people who are exposed to long-term radiation:

are at high risk of developing skin cancer;
have an increased tendency to dry skin, which, in turn, accelerates the aging process and the appearance of pigmentation and early wrinkles;
may suffer from deterioration of visual abilities, cataracts, conjunctivitis;
have weakened immunity.

Lack of vitamin D in humans is one of the causes of malignant neoplasms, metabolic disorders, which leads to excess body weight, endocrine disorders, sleep disorders, physical exhaustion, and bad mood.

A person who systematically receives the light of the sun and does not abuse sunbathing, as a rule, does not experience health problems:

has stable functioning of the heart and blood vessels;
does not suffer from nervous diseases;
has a good mood;
has a normal metabolism;
rarely gets sick.

Thus, only a dosed dose of radiation can have a positive effect on human health.

How to protect yourself

Excessive exposure to radiation can cause overheating of the body, burns, and exacerbation of some chronic diseases.. Fans of sunbathing need to take care of following simple rules:

Sunbathe in open spaces with caution;
During hot weather, hide in the shade under scattered rays. This is especially true for young children and elderly people suffering from tuberculosis and heart disease.

It should be remembered that it is necessary to sunbathe at a safe time of day, and also not to be under the scorching sun for a long time. In addition, you should protect your head from heatstroke by wearing a hat, sunglasses, closed clothing, and also use various sunscreens.

Solar radiation in medicine

Light fluxes are actively used in medicine:

X-rays use the ability of waves to pass through soft tissue and the skeletal system;
the introduction of isotopes makes it possible to record their concentration in internal organs and detect many pathologies and foci of inflammation;
Radiation therapy can destroy the growth and development of malignant tumors.

The properties of waves are successfully used in many physiotherapeutic devices:

Devices with infrared radiation are used for heat treatment of internal inflammatory processes, bone diseases, osteochondrosis, rheumatism, due to the ability of the waves to restore cellular structures.
Ultraviolet rays can have a negative effect on living beings, inhibit plant growth, and suppress microorganisms and viruses.

The hygienic significance of solar radiation is great. Devices with ultraviolet radiation are used in therapy:

various skin injuries: wounds, burns;
infections;
diseases of the oral cavity;
oncological neoplasms.

In addition, radiation has a positive effect on the human body as a whole: it can give strength, strengthen the immune system, and replenish the lack of vitamins.

Sunlight is an important source of a full human life. A sufficient supply of it leads to the favorable existence of all living beings on the planet. A person cannot reduce the degree of radiation, but he can protect himself from its negative effects.