Instructions

The Sun observed from space looks slightly different than from the surface of the Earth, and astronauts in orbit space stations, describe it as a dazzling white ball pressed into the black mass of space. However, its light does not interfere with seeing other objects at the same time: stars, the Moon, the Earth. To observe the sun, you need to use dark filters, as the radiation can scorch the corneas of your eyes. Observing in this way, the disk of the star is clearly visible, and around it the same radiation called the corona is visible. It has 2 million kelvins. Thanks to this radiation, life arose and is maintained on our planet.

Upon close examination of the surface, emissions of a huge amount of energy and matter in the form of prominences are immediately noticeable. Under the influence of powerful magnetic fields, they bend into arcs tens of diameters of our planet. During active years, emissions of matter into space are especially intense. On Earth, they cause auroras and negatively affect radio-electronic equipment.

Along with prominences, sunspots are also visible; these are areas with a lower temperature relative to the temperature of the rest of the surface. That's why they look darker. But they are very hot and have a temperature of about 5 thousand Kelvin. Spots are caused by tension magnetic field stars with an 11-year cycle of appearance. How more spots, the greater the solar activity. The spots also show its rotation around its axis with a period of 27 Earth days.

The Sun actually does not have a clear surface. The visible flat surface is the photosphere. This is a layer 400 km thick, which gradually turns into a boiling convective zone. The difference in the thickness of the photosphere layer and the distance to the Earth is significant, so it is simply not visible and a feeling of a flat surface is created.

Solar dermatitis is an inflammatory reaction of the skin in response to exposure ultraviolet rays. It is also called photodermatosis, phototoxic dermatitis, sun allergy.

Currently, the term “solar dermatitis” unites a group of similar conditions (skin changes), the appearance of which is associated with exposure to sunlight or isolated ultraviolet rays. Determining the form of the disease is the basis for selecting adequate therapy.

What is referred to as solar dermatitis?

Most people use the term “solar dermatitis” to refer to the burn that appears on the skin after excessive sun exposure. In fact, the group of photodermatoses includes quite a lot of conditions that differ in the details of pathogenesis and prognosis. They are united by the dependence of local skin changes on the fact of solar (ultraviolet) irradiation.

The modern classification of photodermatoses (solar dermatitis) includes:

• Phototraumatic reactions. This includes sunburn, actinic dermatitis, solar elastosis and.
• Photodermatoses, the appearance of which is associated with the existing deficiency of natural intradermal protectors. A classic example is xeroderma pigmentosum.
• Photodermatoses caused by the presence of photosensitizing factors in the body, including those of medicinal origin.
• Dermatoses, clinical manifestations which debut, recur or intensify after insolation. In this case, irradiation is not a key pathogenetic moment, but a provoking factor. Such dermatoses include dermatomyositis, systemic lupus erythematosus, and Darier's disease.

But according to the current International classification diseases 10th revision (ICD-10), many forms of solar dermatoses are classified into various classes. And in modern clinical practice Doctors often overlook the importance of insolation in the development and course of a number of dermatological disorders.

Phototraumatic skin changes are considered true solar dermatitis. It can be early (in the first hours after sun exposure), late and chronic.

Why does the skin react to the sun's rays?

As the main reason solar dermatitis insolation appears. Reaching the surface of the Earth sunlight is heterogeneous. It includes rays of the ultraviolet, infrared and visible spectrum. Other forms of radiation are almost completely shielded by the protective ozone layer and the upper atmosphere.

Ultraviolet (UV) radiation is the most traumatic for human skin. It is partially absorbed by epidermal cells, which in most people leads to the formation of characteristic temporary pigmentation - tanning. A person needs to regularly receive small doses of ultraviolet radiation, because it is a necessary condition for the synthesis of vitamin D in the skin.

But with prolonged or severe insolation, a significant part of the UV rays penetrates into the deep layers of the dermis and even into the underlying tissues. At the same time, they act at the cellular and even molecular level, damaging various structures.

UV rays lead to the appearance of free radicals in the thickness of the skin, which have a damaging effect on large specific molecules and cell walls. This is also the reason for the activation of nonspecific inflammatory reaction with local dilation of blood vessels, increasing their permeability, release of biologically active substances. Possibly direct damage keratinocytes.

Under the influence of ultraviolet radiation and free radicals, defective proteins also begin to be produced in the skin. They are perceived by the body as foreign and act as antigens, triggering a delayed immune reaction similar to an allergy. Repeated insolation leads to the release of biologically active substances (acetylcholine and histamine). This provokes the development of diffuse pseudo-inflammatory tissue changes, the appearance of a rash and common features allergies. Local changes when " sun allergy» often extend beyond the zone subjected to excessive insolation.

Ultraviolet in large doses is also capable of disrupting the structure of DNA, causing mutations and thereby provoking tumor growth(and others). And when long-term exposure it leads to degeneration of the main structural protein molecules of the intercellular spaces (collagen and elastin), uneven atrophy connective tissue and early skin aging.

Who is at risk

Under certain conditions, anyone can develop sun dermatitis. But the dose and duration of insolation will be different, as will the severity of the resulting skin changes. This depends on the presence of predisposing factors.

People belonging to Fitzpatrick skin phototypes 1-3 are prone to sun dermatitis. A feature of their dermis is a small amount of melanin, a pigment that can partially shield UV radiation coming from outside. Therefore, even short-term insolation can cause sunburn. varying degrees and at the same time practically does not lead to tanning.

At risk for the development of photodermatoses are people who are prone to excessive tanning (including in solariums) or who, due to the nature of their work, are forced to spend a lot of time on fresh air. Therefore, chronic solar dermatitis is often detected in farm and logging workers, agronomists, gardeners, builders, road workers, rescuers, and fishermen.

Some somatic diseases also change the reactivity of dermal cells and thereby increase the risk of solar dermatitis even with relatively small doses of UV radiation. These include diabetes mellitus and another endocrine pathology, chronic endogenous intoxication(for example, with renal and hepatic failure), obesity.

There is a high risk of developing pathology in individuals with photosensitivity. At the same time, the human body already has antibodies to substances formed under the influence of ultraviolet radiation. Great value They also have photosensitizers.

What are photosensitizers

There are substances that, when introduced into the human body, increase the sensitivity of its cells to UV rays. They are called photosensitizers. They usually enter the body from outside through digestive tract, but a transdermal route of penetration is not excluded.

Photosensitizers include:

• photosensitizer drugs specifically prescribed to the patient, which is sometimes necessary to increase the effectiveness of phototherapy () for psoriasis, trophic ulcers, alopecia areata, vitiligo and a number of others dermatological diseases, as well as in photodynamic therapy of certain forms of cancer;
• photosensitizers with selective accumulation in tumor tissues, their use increases the effectiveness of fluorescent diagnosis of malignant neoplasms;
• some drugs (tetracyclines, sulfonamides, griseofulvin, ibuprofen, typical and atypical antipsychotics and a number of other drugs);
• medicinal herbs used in the form of decoctions (for example, St. John's wort);
• oral contraceptives and sex hormone preparations used for therapeutic or replacement purposes.

A photosensitizing effect can also be observed in people who use cosmetics and deodorizing products with musk. Sometimes the appearance of solar dermatitis is facilitated by creams applied to the skin, settled plant pollen, and household chemicals not thoroughly washed off the hands.

What does solar dermatitis look like?

At acute form disease, symptoms of solar dermatitis appear 3-4 hours after exposure to insolation. The main manifestations resemble a 1st degree burn and include:

• The appearance of erythema - local redness of the skin with blurred boundaries. Its localization corresponds to the insolation zone; the closed areas of the body do not change. It is also possible that erythema may vary in severity over a limited area if, during insolation, a person partially covered the body with clothing.
• Mild diffuse swelling of the skin, the lesion looks compacted.
• Soreness. Even the touch of light clothing causes significant discomfort.
• Itching and burning sensation in the affected area.
• Feeling of dryness and tightness of the skin.

With deeper damage, intradermal blisters appear different sizes with serous contents. After their opening, erosions are formed that do not involve the underlying tissues and heal without scarring. This form of solar dermatitis is called vesiculobullous. In place of the blisters, foci of depigmentation often remain, gradually matching the color of the surrounding skin.

With continued or repeated exposure to sunlight, a fairly profuse rash appears on the skin. It can be papular, nodular, or urticarial (blister-like). Polymorphic rashes are often found. Individual elements have no tendency to merge, they are usually small and moderately itchy. When photosensitizing factors are eliminated and sun exposure is avoided, the rash gradually goes away over 3-8 weeks.

Polymorphic photodermatosis

Not excluded for photodermatitis and general symptoms. This is usually seen in deep or extensive lesions and in children. Malaise, weakness, headache, drowsiness, possible increase in body temperature. Sometimes during the period of rashes the patient notes cheilitis (inflammation of the red border of the lips), conjunctivitis, and mild rhinitis.

Other forms of the disease

With prolonged insolation and repeated episodes acute dermatitis possible development chronic form diseases. In this case, the skin is hyperpigmented and looks dense, dry, thickened, rough, with an enhanced dermal pattern. It often shows scratch marks, an uneven papular rash, small spider veins. These changes appear on the face, sides of the neck, ears, hands and other parts of the body that are not protected by clothing. General condition does not change in chronic dermatitis. But the itching that occurs when the skin is exposed to sunlight can negatively affect the patient’s quality of life.

Chronic course in adults can take the form of keratosis. In this case, the skin becomes covered with hard, non-flaking small scales. They are tightly connected to the underlying layers of the dermis, so their removal is painful and can even lead to capillary bleeding.

A special form of the disease is persistent solar erythema. It initially does not differ from typical dermatitis, but the erythema and rash persist for many months. Any new exposure to ultraviolet rays leads to a worsening of the condition.

Why is solar dermatitis dangerous?

Solar dermatitis does not pose an immediate threat to life, even in a child. But it increases the risk of developing skin cancer. This is due to the appearance of a significant number of mutations under the influence of ultraviolet radiation, as well as the immunosuppressive effect of excessive insolation. And some forms of the disease () WHO specialists currently classify as precancerous.

Actinic keratosis

Regularly received excess sunlight contributes to photoaging of the skin. The defects that arise in this case are less amenable to correction by means aesthetic medicine than natural age-related changes. Of course, photoaging is not dangerous, but it negatively affects psychological state women and can even lead to neurosis-like reactions.

Principles of therapy

Treatment of solar dermatitis includes avoiding sun exposure, eliminating photosensitizers, and using products to relieve skin changes. Hospitalization is usually not required.

At mild form illness may be enough local treatment folk remedies. But protracted, severe cases accompanied by a rash require the use of medicines topical and systemic action.

IN acute stage disease treatment at home includes the use of lotions with lead water, 2% boric acid. This allows you to reduce swelling and itching of the skin, and cope with the painful feeling of tightness. In the absence of signs of infection, treatment with folk remedies is acceptable: wet wraps with anti-inflammatory infusions medicinal plants, green tea.

Ascorutin, antihistamines and non-steroidal anti-inflammatory drugs are the basic drugs for solar dermatitis. Aevit, Delagil, Plaquenil are also prescribed.

In case of severe inflammation, the addition of a photoallergic reaction and a tendency to a protracted course, glucocorticosteroid drugs are used as prescribed by a doctor. Ointment and cream for solar dermatitis are applied for a strictly defined period of time to avoid the development of secondary fungal infections of the skin and tissue atrophy. It can also be carried out short-term systemic therapy, in this case, tablets or even injectable forms of the drug are prescribed.

Solar dermatitis is a fairly common disease. And the deterioration of the environmental situation, the gradual destruction of the Earth’s ozone layer and increased solar activity make the problem more and more urgent. Treatment of photodermatoses is not only an improvement in the patient’s quality of life, but also the prevention of skin cancer and melanoma. Prevention includes limiting exposure to open sun and ensuring daily use.

Let's start with Mercury. Mercury is an extremely hot world because it is very close to the Sun and has no atmosphere to shield it from the sun's heat. The lack of atmosphere determines what Mercury's sky looks like. The stars on Mercury are visible only at night; during the day they are not visible due to the fact that the Sun shines very brightly and outshines the stars with its brilliance. The solar disk is approximately three times larger than that of Earth. Temperature at night -180, during the day +430.

There is very interesting feature Mercury sky. Once a Mercurian year, for about 8 days, the sun is in the sky Mercury first it stops and then starts moving in the other direction. After eight days, the sun stops again, and then resumes its normal movement.

The second planet from the Sun is Venus. You won’t see the sun from the surface because of dense clouds of sulfuric acid, the pressure will squeeze out your eyes, and the temperature is even higher than on Mercury (+480°C), so you’re unlikely to have time to see anything.

Red planet - Mars. The sun on Mars is 1.5 times smaller. The sunset is not red like on Earth, but bluish. The reason for this color of the sky is the same that on Earth gives a blue sky and a red sunset - Rayleigh scattering. The difference between the color of the sky at noon and at sunset is in the volume of the atmosphere that is overcome sun rays. On Mars, the atmosphere is a hundred times thinner than on Earth, but when the Sun is at the horizon, its light travels thirty times more. thick layer atmosphere than at noon.

Jupiter- the largest planet in our system in every sense. A giant ball of gas, inside which hydrogen acquires metallic properties. The sun is 5.2 times smaller. As it dives into the atmosphere, the Sun will be covered by clouds different colors: Mostly blue, brown and red. However, Jupiter emits more heat than it receives from the outside.

Jupiter has several rings made of dust and tiny asteroids. These rings can be visible from latitudes far from the equator. In addition, several moons can be seen in the sky of Jupiter: Io, Europa, Callisto and Ganymede. The most noticeable of them will be Io: from Jupiter it will appear slightly larger than our Earth's Moon.

Lord of the Rings - Saturn. The most beautiful planet Solar system. The size of the solar disk is on average 9.5 times (!) smaller than ours. Also gas giant, emits more heat than it receives from the Sun.

Uranus- a truly unique planet. Uranus is unique in its location, its axis is tilted at 98 degrees, which forces the original planet to orbit while lying on its side. In this position, the main flow is directed towards the pole areas solar energy, but, contrary to logical conclusions, the temperature at the equator has more high performance. The direction of rotation of the ice giant is the opposite of its orbital motion. Uranus makes one revolution in 84 Earth years, and a day passes in 17 hours; this period is calculated approximately due to the uneven movement of the gaseous surface. In short, imagining how the Sun moves across the sky requires your brain to boil.

Neptune- blue giant. The winds blowing on Neptune have a unique speed, its average is 1000 km/h, and hurricane gusts reach 2400 km/h. Air masses move against the planet's axis of rotation. An inexplicable fact is the increase in storms and winds, which is observed with increasing distance between the planet and the Sun. The sun is 30 times smaller than the earth's.

There are thirteen known satellites of Neptune. The largest of them, Triton, will appear slightly larger than our Moon; the next largest Proteus will be half the size. The remaining moons of Neptune are small and will be visible as ordinary stars.

Pluto 40 times farther from the Sun than the Earth, so little solar energy and light comes here that our star can be confused with a large star. Pluto and its moon Charon orbit each other, and Pluto's orbit is sharply tilted relative to the other planets. A year on Pluto lasts 248 Earth years. And a day is almost a week. The surface temperature ranges from minus 228 to minus 238 °C.

*Illustrations by Ron Miller

Our solar system is amazing beautiful place. And thanks to modern telescopes and spacecraft, we can enjoy the volcanoes of Mercury, the crimson plains of Mars, the beautiful rings of Saturn, and even the dark icy desert of Pluto.

Illustrator Ron Miller worked with NASA specialists to recreate photographs of sunrises and sunsets that we - purely theoretically - could observe on different planets neighboring the Earth.

This is what the Sun looks like on the surface of Mercury. The distance between the two celestial bodies is 58 million kilometers.

Here is Venus covered with volcanoes and lava. Its atmosphere consists almost entirely of carbon dioxide, so there is a constant thunderstorm, hellish heat and almost no sun visible. The distance to it is 108 million kilometers.

Here is a rare photo of the Sun from Earth during an eclipse. Distance – 150 million kilometers.
This is what a sunny day on Mars looks like. The distance from the planet to the star is 228 million kilometers.

Here's what you would see on Jupiter. The sun seems small: the distance is 779 million kilometers. The view is blocked by Europa, Jupiter's largest satellite.

Here's what you might see on Saturn if you got there. The distance to the Sun is 1.43 billion kilometers.

And this is what dawn looks like on Uranus. The Sun is 2.88 billion kilometers from here, but nearby is Ariel, the main “Moon” of Uranus.

And this is the surface of Neptune. A huge Triton (satellite), huge geysers on the surface, ice and a tiny sun, which, nevertheless, is clearly visible. Distance – 4.5 billion kilometers.

And finally, here's what you would see on Pluto. From here to the Sun is 5.91 billion kilometers.

Sunsets are beautiful from anywhere in the solar system. And although we will never be able to enjoy them in person, satellites, telescopes and computer simulations allow us to see breathtaking images.

The closest planet to the Sun is Mercury. The solar disk is approximately three times larger than that of Earth. Temperature at night: −180 °C, during the day: +430 °C.

The second planet from the Sun is Venus. You won’t see the sun from the surface because of dense clouds of sulfuric acid, the pressure will squeeze out your eyes, and the temperature is even higher than on Mercury (+480 °C), so you’re unlikely to have time to see anything.

And here is the third planet from the Sun. How do you like this rare angle?

Red planet - Mars. The sun on Mars is 1.5 times smaller. The sunset is not red, like on Earth, but bluish. The reason for this color of the sky is the same that on Earth gives a blue sky and a red sunset - Rayleigh scattering... The difference between the color of the sky at noon and at sunset is in the volume of the atmosphere that is overcome by the sun's rays. On Mars, the atmosphere is a hundred times thinner than on Earth, but when the Sun is near the horizon, light travels thirty times thicker through the atmosphere than at midday.

Jupiter is the largest planet in our system in every sense. A giant ball of gas, inside which hydrogen acquires metallic properties. The sun is 5.2 times smaller. However, Jupiter emits more heat than it receives from the outside. And here is the view from the Europa satellite:

Lord of the Rings - Saturn. The most beautiful planet in the solar system. The size of the solar disk is on average 9.5 times (!) smaller than ours. The gas giant also emits more heat than it receives from the Sun.

Uranus is a truly unique planet. Uranus is unique in its location, its axis is tilted at 98 degrees, which forces the planet to orbit while lying on its side. In this position, the main flow of solar energy is directed to the polar regions, but contrary to logical conclusions, the temperature at the equator has higher values. The direction of rotation of the ice giant is the opposite of its orbital motion. Uranus makes one revolution in 84 Earth years, and a day passes in 17 hours; this period is calculated approximately due to the uneven movement of the gaseous surface. It is impossible to imagine how the Sun moves across the sky without the brain boiling (for Mercury it is even worse). And here is a satellite view of Ariel:

Neptune is a blue giant. Neptune's winds have a unique speed, the average is 1000 km/h, and hurricane gusts are 2400 km/h. Air masses move against the planet's axis of rotation. An inexplicable fact is the increase in storms and winds, which is observed with increasing distance between the planet and the Sun. Attention! The sun is 30 times smaller than the earth's. Not the best best place admiring the sunset, but here's the view from Triton:

Well, and our little brother, whom everyone offends, is the dwarf planet Pluto. It is 40 times further from the Sun than the Earth; so little solar energy and light comes here that our star can be confused with a large star. Pluto and its moon Charon orbit each other, and Pluto's orbit is sharply tilted relative to the other planets. A year on Pluto lasts 248 Earth years. And a day is almost a week. The surface temperature ranges from - 228 to - 238 °C.