• We can install a series of large reflectors at the Lagrange point L1 to keep some of the light from reaching the Earth.
• We can geoengineer our planet's atmosphere/albedo so that it reflects more light and absorbs less.
• We can rid the planet of the greenhouse effect by removing methane and carbon dioxide molecules from the atmosphere.
• We can leave Earth and focus on terraforming outer worlds like Mars.

In theory, everything can work, but it will require tremendous effort and support.

However, the decision to migrate the Earth to a distant orbit may become final. And although we will have to constantly remove the planet from orbit in order to maintain a constant temperature, this will take hundreds of millions of years. To compensate for the effect of a 1% increase in the luminosity of the Sun, the Earth must be moved 0.5% of the distance from the Sun; to compensate for the 20% increase (i.e., in 2 billion years), the Earth must be pulled 9.5% further. The Earth will no longer be 149,600,000 km from the Sun, but 164,000,000 km.

The distance from the Earth to the Sun has not changed much over the past 4.5 billion years. But if the Sun continues to heat up and we don't want the Earth to be completely fried, we will have to seriously consider the possibility of planetary migration.

This takes a lot of energy! To move the Earth - all of its six septillion kilograms (6 x 10 24) - away from the Sun - means to significantly change our orbital parameters. If we move the planet from the Sun to 164,000,000 km, obvious differences will be noticeable:

• The Earth will orbit the Sun 14.6% longer
• to maintain a stable orbit, our orbital speed must drop from 30 km/s to 28.5 km/s
• if the period of rotation of the Earth remains the same (24 hours), the year will not be 365, but 418 days
• The Sun will be much smaller in the sky - by 10% - and the tides caused by the Sun will be weaker by a few centimeters

If the Sun swells in size and the Earth moves away from it, these two effects do not quite cancel out; The sun will appear smaller from Earth

But in order to bring the Earth this far, we need to make very large energy changes: we will need to change the gravitational potential energy of the Sun-Earth system. Even taking into account all other factors, including the deceleration of the Earth around the Sun, we will have to change the Earth's orbital energy by 4.7 x 10 35 joules, which is equivalent to 1.3 x 10 20 terawatt-hours: 10 15 times the annual energy cost carried by humanity. One would think that in two billion years they would be different, and they are, but not by much. We will need 500,000 times more energy than humanity generates worldwide today, all of which will be used to move the Earth to safety.

The speed at which the planets revolve around the Sun depends on their distance from the Sun. Earth's slow migration of 9.5% of the distance will not disturb the orbits of other planets.

Technology is not the most difficult issue. The difficult question is much more fundamental: how do we get all this energy? In reality, there is only one place that will satisfy our needs: the Sun itself. Currently, the Earth receives about 1500 watts of energy per square meter from the Sun. In order to get enough power to move the Earth in the right amount of time, we would have to build an array (in space) that would collect 4.7 x 10 35 joules of energy, uniformly, over 2 billion years. This means that we need an array of 5 x 10 15 square meters (and 100% efficiency), which is equivalent to the entire area of ​​ten planets, like ours.

The concept of space solar energy has been developed for a long time, but no one has yet imagined an array of solar cells measuring 5 billion square kilometers.

Therefore, to transport the Earth to a safe orbit far away, you need a solar panel of 5 billion square kilometers of 100 percent efficiency, all of whose energy will be spent on pushing the Earth into another orbit for 2 billion years. Is it physically possible? Absolutely. With modern technology? Not at all. Is it practically possible? With what we know now, almost certainly not. Dragging an entire planet is difficult for two reasons: firstly, because of the force of the Sun's gravitational pull, and because of the massiveness of the Earth. But we have just such a Sun and such an Earth, and the Sun will heat up regardless of our actions. Until we figure out how to collect and use this amount of energy, we will need other strategies.

There are 3 options for deorbiting - move to a new orbit (which, in turn, may be closer or farther from the sun, or even be very elongated), fall into the Sun and leave the solar system. Consider only the third option, which, in my opinion, is the most interesting.

As we move further away from the sun, there will be less ultraviolet light for photosynthesis and the average temperature on the planet will decrease year by year. Plants will be the first to suffer, resulting in severe shocks to food chains and ecosystems. And the ice age will come quickly enough. The only oases with more or less conditions will be near geothermal springs, geysers. But not for long.

After a certain number of years (by the way, there will be no more seasons), at a certain distance from the sun, unusual rains will begin on the surface of our planet. It will be rains of oxygen. If you're lucky, maybe it will snow from oxygen. Whether people will be able to adapt to this on the surface, I can’t say for sure - there will be no food either, steel in such conditions will be too fragile, so it’s unclear how to extract fuel. the surface of the ocean will freeze to a solid depth, the ice cap will cover the entire surface of the planet except for the mountains due to the expansion of ice - our planet will turn white.

But the temperature of the core of the planet, the mantle will not change, so that under the ice cap at a depth of several kilometers the temperature will remain quite tolerable. (if you dig such a mine and provide constant food and oxygen, you can even live there)

The funniest thing is in the depths of the sea. Where even now no light beam penetrates. There, at a depth of several kilometers under the surface of the ocean, there are entire ecosystems that absolutely do not depend on the sun, on photosynthesis, or on solar heat. They have their own cycles of substances, chemosynthesis instead of photosynthesis, and the desired temperature is maintained by the heat of our planet (volcanic activity, underwater hot springs, and so on). Since the temperature inside our planet is provided by its gravity, mass, even without the sun, then outside the solar systems, stable conditions will be maintained there, the desired temperature. And the life that boils in the depths of the sea, at the bottom of the ocean, will not even notice that the sun is gone. That life will not even know that our planet once revolved around the sun. Perhaps it will evolve.

It is also unlikely but also possible that a snowball - the Earth someday, after billions of years, will fly to one of the stars of our galaxy and fall into its orbit. It is also possible that in that orbit of another star our planet will "thaw" and favorable conditions for life will appear on the surface. Perhaps life in the depths of the sea, having overcome all this path, will again come to the surface, as it already happened once. Perhaps, as a result of evolution on our planet after this, intelligent life will reappear. And finally, maybe they will find surviving media with questions and answers of the site in the remains of one of the data centers

It is impossible to explain … September 29th, 2016

Scientists from the NASA Jet Propulsion Laboratory and Los Alamos National Laboratory (USA) have compiled a list of astronomical phenomena observed in the solar system that are completely impossible to explain ...

These facts have been repeatedly verified, and there is no reason to doubt their reality. Yes, but they do not fit into the existing picture of the world at all. And this means that either we do not quite correctly understand the laws of nature, or ... someone is constantly changing these same laws.

See some examples here:

Who accelerates space probes

In 1989, the Galileo spacecraft set off on a long journey to Jupiter. In order to give it the desired speed, scientists used a "gravitational maneuver". The probe approached the Earth twice so that the planet's gravity could "push" it, giving it additional acceleration. But after the maneuvers, the speed of the Galileo turned out to be higher than calculated.

The technique was worked out, and earlier all devices accelerated normally. Then the scientists had to send three more research stations into deep space. The NEAR probe went to the asteroid Eros, the Rosetta flew to study the Churyumov-Gerasimenko comet, and the Cassini went to Saturn. All of them performed the gravitational maneuver in the same way, and for all of them the final speed turned out to be more than the calculated one - scientists followed this indicator seriously after the noticed anomaly with Galileo.

There was no explanation for what was happening. But all the vehicles sent to other planets after Cassini, for some reason, did not receive a strange additional acceleration during the gravitational maneuver. So what was the "something" between 1989 (Galileo) and 1997 (Cassini) that gave all the probes that went into deep space an extra boost?

Scientists are still shrugging their shoulders: who needed to “push” four satellites? In ufological circles, there was even a version that a certain Higher Mind decided that it would be necessary to help earthlings explore the solar system.

Now this effect is not observed, and whether it will ever appear again is unknown.

Why is the earth running away from the sun?

Scientists have long since learned to measure the distance from our planet to the star. Now it is considered equal to 149,597,870 kilometers. Previously, it was believed that it was immutable. But in 2004, Russian astronomers found that the Earth is moving away from the Sun by about 15 centimeters a year - that's 100 times more than the measurement error.

What happens that was previously described only in science fiction novels: the planet went to "free floating"? The nature of the journey that began is still unknown. Of course, if the rate of removal does not change, then hundreds of millions of years will pass before we move away from the Sun so much that the planet freezes. But suddenly the speed will increase. Or, on the contrary, the Earth will begin to approach the star?

So far, no one knows what will happen next.

Who "pioneers" does not let abroad

The American probes Pioneer 10 and Pioneer 11 were launched in 1972 and 1983, respectively. By now, they should have already left the solar system. However, at a certain moment, both one and the second, for unknown reasons, began to change their trajectory, as if an unknown force did not want to let them go too far.

"Pioneer-10" has already deviated by four hundred thousand kilometers from the calculated trajectory. "Pioneer-11" exactly repeats the path of a fellow. There are many versions: the influence of the solar wind, fuel leakage, programming errors. But all of them are not very convincing, since both ships, launched with an interval of 11 years, behave in the same way.

If you do not take into account the intrigues of aliens or the divine plan not to let people out of the solar system, then perhaps the influence of the mysterious dark matter is manifested here. Or are there some gravitational effects unknown to us?

What lurks on the outskirts of our system

Far, far beyond the dwarf planet Pluto is the mysterious asteroid Sedna, one of the largest in our system. In addition, Sedna is considered the reddest object in our system - it is even redder than Mars. Why is unknown.

But the main mystery lies elsewhere. It makes a complete revolution around the Sun in 10 thousand years. Moreover, it circulates in a very elongated orbit. Either this asteroid came to us from another star system, or maybe, as some astronomers believe, it was knocked out of a circular orbit by the gravitational attraction of some large object. What? Astronomers have no way of detecting it.

Why solar eclipses are so perfect

In our system, the dimensions of the Sun and Moon, as well as the distance from the Earth to the Moon and to the Sun, are selected in a very original way. If a solar eclipse is observed from our planet (by the way, the only one where there is intelligent life), then the disk of Selena perfectly covers the disk of the star perfectly evenly - their sizes coincide exactly.

If the Moon were a little smaller or farther from the Earth, then we would never have total solar eclipses. Accident? Something is unbelievable...

Why do we live so close to our star

In all star systems studied by astronomers, the planets are arranged in the same order: the larger the planet, the closer it is to the star. In our solar system, the giants - Saturn and Jupiter - are located in the middle, skipping ahead of the "kids" - Mercury, Venus, Earth and Mars. Why this happened is unknown.

If we had the same world order as in the vicinity of all other stars, then the Earth would be somewhere in the region of today's Saturn. And there reigns hellish cold and no conditions for intelligent life.

Radio signal from the constellation Sagittarius

In the 1970s, a program began in the United States to search for possible alien radio signals. To do this, the radio telescope was directed to different parts of the sky, and he scanned the ether at different frequencies, trying to detect a signal of artificial origin.

For several years, astronomers could not boast of at least some results. But on August 15, 1977, while astronomer Jerry Ehman was on duty, a recorder recording everything that fell into the “ears” of the radio telescope recorded a signal or noise that lasted 37 seconds. This phenomenon is called Wow! - according to a marginal note, which was brought out in red ink by the stunned Ehman.

"Signal" was at a frequency of 1420 MHz. According to international agreements, no terrestrial transmitter operates in this range. He proceeded from the direction of the constellation Sagittarius, where the nearest star is located at a distance of 220 light years from Earth. Whether it was artificial - there is still no answer. Subsequently, scientists have repeatedly searched this area of ​​the sky. But to no avail.

Dark matter

All galaxies in our universe revolve around the same center at high speed. But when scientists calculated the total masses of galaxies, it turned out that they are too light. And according to the laws of physics, this whole carousel would have broken long ago. However, it doesn't break.

To explain what is happening, scientists came up with a hypothesis that there is some kind of dark matter in the Universe that cannot be seen. But here's what it is and how to feel it, astronomers do not yet represent. We only know that its mass is 90% of the mass of the universe. And this means that we know what kind of world surrounds us, only one tenth.

Life on Mars

The search for organics on the Red Planet began in 1976 - the American Viking spacecraft landed there. They had to conduct a series of experiments in order to either confirm or disprove the hypothesis of the habitability of the planet. The results turned out to be contradictory: on the one hand, methane was detected in the atmosphere of Mars - obviously, of biogenic origin, but not a single organic molecule was identified.

The strange results of the experiments were attributed to the chemical composition of the Martian soil and decided that there was still no life on the Red Planet. However, a number of other studies suggest that there was once moisture on the surface of Mars, which again speaks in favor of the existence of life. According to some, we can talk about underground life forms.

What riddles are not worth a damn?

sources

something your conversation - "broke through":

What is the distance from the Earth to the Sun?

The distance between the Earth and the Sun ranges from 147 to 152 million km. It was very accurately measured using radar.

What is a light year?

A light year is a distance of 9460 billion km. It is this path that light travels in a year, moving at a constant speed of 300,000 km / s.

How far is it to the moon?

The moon is our neighbor. The distance to it at the point of the orbit closest to the Earth is 356410 km. The maximum distance of the Moon from the Earth is 406697 km. The distance was calculated from the time it took for the laser beam to reach the moon and return back, reflected from the mirrors left on the surface of the moon by American astronauts and Soviet lunar vehicles.

What is a parsec?

A parsec is equal to 3.26 light years. Parallax distances are measured in parsecs, that is, distances calculated geometrically from the smallest shifts in the apparent position of a star as the Earth moves around the Sun.

What is the farthest star you can see?

The most distant space objects that can be observed from Earth are quasars. They are at a distance of 13 billion light years from Earth.

Are the stars receding?

Redshift studies show that all galaxies are moving away from ours. The farther, the faster they move. The most distant galaxies move almost at the speed of light.

How was the distance to the Sun first measured?

In 1672, two astronomers - Cassini in France and Riecher in Guiana - noted the exact position of Mars in the sky. They calculated the distance to Mars from the small difference between the two measurements. And then scientists using elementary geometry calculated the distance from the Earth to the Sun. The value obtained by Cassini turned out to be underestimated by 7%.

What is the distance to the nearest star?

The closest star to the solar system is Proxima Centauri, the distance to it is 4.3 light years, or 40 trillion. km.

How do astronomers measure distances?

What is the distance from the Earth to the Sun?

Sun(hereinafter referred to as S.) - the central body of the solar system, is a hot plasma ball; S. is the closest star to Earth. Weight S. - 1,990 1030 kg(332,958 times the mass of the Earth). 99.866% of the mass of the solar system is concentrated in S. Solar parallax (the angle at which the equatorial radius of the Earth is visible from the center of S., which is at an average distance from S., is 8 "794 (4.263'10 \u003d 5 rad). The distance from the Earth to S(astronomical unit). The average angular diameter of S. is 1919",26 (9.305'10 = 3 rad), which corresponds to the linear diameter of S. 1.392'109 m (109 times the diameter of the Earth's equator). The average density of S. 1.41'103 kg / m3 The acceleration of gravity on the surface of S. is 273.98 m/s2 The parabolic velocity on the surface of S. (second cosmic velocity) is 6.18'105 m/s The effective temperature of the surface of S., determined according to the Stefan-Boltzmann law radiation, according to the total radiation of S. (see Solar radiation), is equal to 5770 K.

The history of telescopic observations of S. begins with observations made by G. Galileo in 1611; sunspots were discovered, and the period of solar revolution around its axis was determined. In 1843, the German astronomer G. Schwabe discovered the cyclicity of solar activity. The development of methods of spectral analysis made it possible to study the physical conditions on the Sun. In 1814, J. Fraunhofer discovered dark absorption lines in the spectrum of the Sun; this marked the beginning of the study of the chemical composition of the Sun. Since 1836, eclipses of the Sun have been regularly observed, which led to the discovery of the corona and chromosphere of the Sun. ., as well as solar prominences. In 1913, the American astronomer J. Hale observed the Zeeman splitting of the Fraunhofer lines in the spectrum of sunspots and thus proved the existence of magnetic fields in the north. By 1942, the Swedish astronomer B. Edlen and others had identified several lines in the spectrum of the solar corona with lines of highly ionized elements, thus proving the high temperature in the solar corona. In 1931, B. Lio invented a solar coronagraph, which made it possible to observe the corona and chromosphere without eclipses. In the early 40s. 20th century radio emission from the sun was discovered. was the development of magnetohydrodynamics and plasma physics. Since the beginning of the space age, the ultraviolet and X-ray radiation of solar radiation has been studied by the methods of extra-atmospheric astronomy using rockets, automatic orbital observatories on Earth's satellites, and space laboratories with people on board. In the USSR, research on solar radiation is being conducted at the Crimean and Pulkovo observatories and at astronomical institutions in Moscow, Kyiv, Tashkent, and Alma-Ata. Abastumani, Irkutsk, and others. Most foreign astrophysical observatories are engaged in S. research (see Astronomical Observatories and Institutes).

S.'s rotation around the axis occurs in the same direction as the Earth's rotation, in a plane inclined by 7? 15 "to the plane of the Earth's orbit (the ecliptic). The rotation speed is determined by the apparent movement of various parts in the S.'s atmosphere and by the shift of spectral lines in the spectrum of the solar disk edge due to the Doppler effect.Thus, it was found that the solar rotation period is not the same at different latitudes.The position of various details on the solar surface is determined using heliographic coordinates measured from the solar equator (heliographic latitude) and from the central meridian visible disk of S. or from some meridian chosen as the initial one (the so-called Carrington meridian). At the same time, it is believed that S. rotates like a solid body. The position of the initial meridian is given in the Astronomical Yearbooks for each day. Information about the position of the N axis on the celestial sphere.Points with a heliographic latitude of 17° make one revolution relative to the Earth in 27.275 days ( synodic period). The rotation time at the same latitude of the North relative to the stars (sidereal period) is 25.38 days. The angular velocity of rotation w for sidereal rotation varies with heliographic latitude j according to the law: w = 14?, 44-3? sin2j per day. The linear velocity of rotation at the equator of the North is about 2,000 m/sec.

S. as a star is a typical yellow dwarf and is located in the middle part of the main sequence of stars on the Hertzsprung-Russell diagram. The apparent photovisual magnitude of S. is - 26.74, the absolute visual magnitude of Mv is + 4.83. The color index of S. is for the case of the blue (B) and visual (V) regions of the spectrum MB - MV = 0.65. Spectral class C. G2V. The speed of movement relative to the totality of the nearest stars is 19.7 × 103 m / s. S. is located inside one of the spiral arms of our Galaxy at a distance of about 10 kpc from its center. The period of solar revolution around the center of the Galaxy is about 200 million years. S.'s age is about 5–109 years.

The internal structure of S. is determined on the assumption that it is a spherically symmetrical body and is in equilibrium. The energy transfer equation, the law of conservation of energy, the ideal gas equation of state, the Stefan-Boltzmann law, and the conditions of hydrostatic, radiant, and convective equilibrium, together with the values ​​of the total luminosity, total mass, and radius of C. determined from observations, and data on its chemical composition, make it possible to build a model The internal structure of S. It is believed that the content of hydrogen in S. by weight is about 70%, helium is about 27%, and the content of all other elements is about 2.5%. Based on these assumptions, it was calculated that the temperature in the center of S. is 10-15?106 K, the density is about 1.5'105 kg/m3, and the pressure is 3.4'1016 N/m2 (about 3'1011 atmospheres). It is believed that the source of energy that replenishes radiation losses and maintains the high temperature of C. are nuclear reactions occurring in the depths of C. The average amount of energy generated inside C. is 1.92 erg per g per second. The release of energy is determined by nuclear reactions where hydrogen is converted to helium. On S., 2 groups of thermonuclear reactions of this type are possible: the so-called. proton-proton (hydrogen) cycle and carbon cycle (Bethe cycle). It is most likely that the proton-proton cycle, which consists of three reactions, predominates in solarium, in the first of which deuterium nuclei (a heavy isotope of hydrogen, atomic mass 2) are formed from hydrogen nuclei; in the second of the deuterium nuclei, nuclei of a helium isotope with an atomic mass of 3 are formed, and, finally, in the third of them, nuclei of a stable helium isotope with an atomic mass of 4 are formed.

The transfer of energy from the inner layers of solarium mainly occurs through the absorption of electromagnetic radiation coming from below and subsequent reradiation. As a result of a decrease in temperature with distance from the center of solar radiation, the wavelength of radiation gradually increases, which transfers most of the energy to the upper layers (see the Wine law of radiation). The transfer of energy by the movement of hot matter from the inner layers, and cooled inside (convection) plays a significant role in the relatively higher layers that form the convective zone of solar radiation, which begins at a depth of about 0.2 solar radii and has a thickness of about 108 m. The speed of convective movements increases with distance from the center of solarium and reaches (2–2, 5)?103 m/sec. In still higher layers (in the atmospheric atmosphere), energy is again transferred by radiation. In the upper layers of the solar atmosphere (in the chromosphere and corona), part of the energy is delivered by mechanical and magnetohydrodynamic waves, which are generated in the convective zone but are absorbed only in these layers. The density in the upper atmosphere is very low, and the necessary energy removal due to radiation and heat conduction is possible only if the kinetic temperature of these layers is high enough. Finally, in the upper part of the solar corona, most of the energy is carried away by flows of matter moving away from the sun, the so-called. sunny wind. the temperature in each layer is set at such a level that the energy balance is automatically carried out: the amount of energy brought in due to the absorption of all types of radiation, thermal conductivity or the movement of matter is equal to the sum of all energy losses of the layer.

The total radiation of solar radiation is determined by the illumination it creates on the surface of the earth—about 100,000 lux when solar is at its zenith. Outside the atmosphere, at the mean distance of the earth from the north, the illumination is 127,000 lux. The luminous intensity of S. is 2.84 × 1027. The amount of light energy that comes in 1 minute to an area of ​​1 cm3, set perpendicular to the sun's rays outside the atmosphere at the average distance of the Earth from S., is called the solar constant. The power of the total radiation of S. is 3.83 × 1026 watts, of which about 2 × 1017 W hit the Earth, the average brightness of the S. surface (when observed outside the Earth’s atmosphere) is 1.98 × 109 nt, the brightness of the center of the S. disk is 2.48×109 nt. The brightness of the S. disk decreases from the center to the edge, and this decrease depends on the wavelength, so that the brightness at the edge of the S. disk, for example, for light with a wavelength of 3600 A, is about 0.2 of the brightness of its center, and for 5000 A - about 0.3 of the brightness of the center of the C. disk. At the very edge of the C. disk, the brightness drops by a factor of 100 over less than one second of the arc, so the border of the C. disk looks very sharp (Fig. 1).

The spectral composition of light emitted by solar radiation, i.e., the distribution of energy in the spectrum of solar radiation (after taking into account the influence of absorption in the earth’s atmosphere and the influence of Fraunhofer lines), in general terms corresponds to the distribution of energy in the radiation of an absolutely black body with a temperature of about 6000 K. However, there are noticeable deviations in some parts of the spectrum. The maximum energy in the spectrum of S. corresponds to a wavelength of 4600 A. The spectrum of S. is a continuous spectrum, on which more than 20 thousand absorption lines (Fraunhofer lines) are superimposed. More than 60% of them have been identified with the spectral lines of known chemical elements by comparing the wavelengths and relative intensity of the absorption line in the solar spectrum with laboratory spectra. The study of Fraunhofer lines provides information not only about the chemical composition of the solar atmosphere, but also about the physical conditions in the layers in which certain absorption lines form. The predominant element in S. is hydrogen. The number of helium atoms is 4-5 times less than that of hydrogen. The number of atoms of all other elements combined is at least 1000 times less than the number of hydrogen atoms. Among them, the most abundant are oxygen, carbon, nitrogen, magnesium, silicon, sulfur, iron, and others. Lines belonging to certain molecules and free radicals can also be identified in the spectrum of C.: OH, NH, CH, CO, and others.

Magnetic fields on S. are measured mainly by the Zeeman splitting of absorption lines in the spectrum of S. (see the Zeeman effect). There are several types of magnetic fields in the north (see solar magnetism). The total magnetic field of the solar system is small and reaches a strength of 1 Oe of one polarity or another and changes with time. This field is closely related to the interplanetary magnetic field and its sectoral structure. Magnetic fields associated with solar activity can reach a strength of several thousand e in sunspots. The structure of magnetic fields in active regions is very intricate, magnetic poles of different polarity alternate. There are also local magnetic regions with field strengths of hundreds of Oe outside sunspots. Magnetic fields penetrate both the chromosphere and the solar corona. Magnetogasdynamic and plasma processes play an important role in the north. At a temperature of 5000-10,000 K, the gas is sufficiently ionized, its conductivity is high, and due to the enormous scale of solar phenomena, the importance of electromechanical and magnetomechanical interactions is very large (see Cosmic magnetohydrodynamics).

S.'s atmosphere is formed by external layers accessible to observations. Almost all solar radiation comes from the lower part of its atmosphere, called the photosphere. Based on the equations of radiative energy transfer, radiative and local thermodynamic equilibrium, and the observed radiation flux, one can theoretically construct a model for the distribution of temperature and density with depth in the photosphere. The thickness of the photosphere is about 300 km, its average density is 3×10=4 kg/m3. the temperature in the photosphere drops as one moves to more outer layers, its average value is about 6000 K, at the boundary of the photosphere it is about 4200 K. The pressure varies from 2 × 104 to 102 N/m2. The existence of convection in the subphotospheric zone of the solarium is manifested in the uneven brightness of the photosphere and its visible granularity—the so-called granularity. granulation structure. The granules are bright spots of a more or less round shape, visible on the image of S., obtained in white light (Fig. 2). The size of the granules is 150-1000 km, the lifetime is 5-10 min. individual granules can be observed for 20 minutes. Sometimes granules form clusters up to 30,000 km in size. Granules are brighter than intergranular spaces by 20–30%, which corresponds to an average temperature difference of 300 K. Unlike other formations, granulation on the surface of S. is the same at all heliographic latitudes and does not depends on solar activity. The velocities of chaotic motions (turbulent velocities) in the photosphere are, according to various definitions, 1-3 km/sec. In the photosphere, quasi-periodic oscillatory motions in the radial direction have been found. They occur on sites 2-3 thousand km in size, with a period of about 5 minutes and a velocity amplitude of the order of 500 m/s. After several periods, oscillations in a given place fade, then may arise again. Observations also showed the existence of cells in which movement occurs in the horizontal direction from the center of the cell to its boundaries. The speed of such movements is about 500 m/sec. Cell sizes - supergranules - 30-40 thousand km. The position of the supergranules coincides with the cells of the chromospheric grid. At the boundaries of supergranules, the magnetic field is enhanced. It is assumed that supergranules reflect the existence of convective cells of the same size at a depth of several thousand km below the surface. Initially, it was assumed that the photosphere gives only continuous radiation, and the absorption lines are formed in the reversal layer located above it. Later it was found that both spectral lines and a continuous spectrum are formed in the photosphere. However, to simplify mathematical calculations in the calculation of spectral lines, the concept of a reversing layer is sometimes used.

Sunspots and torches. Sunspots and flares are often observed in the photosphere (Figs. 1 and 2). Sunspots are dark formations, usually consisting of a darker core (shadow) and the penumbra surrounding it. Spot diameters reach 200,000 km. Sometimes the spot is surrounded by a light border. Very small spots are called pores. The lifetime of spots is from several hours to several months. Even more lines and absorption bands are observed in the spectrum of spots than in the spectrum of the photosphere; it resembles the spectrum of a star of the spectral type KO. Line shifts in the spectrum of spots due to the Doppler effect indicate the movement of matter in the spots - outflow at lower levels and inflow at higher levels, the movement speeds reach 3 × 103 m/s (Evershed effect). From comparisons of the line intensities and the continuous spectrum of spots and the photosphere, it follows that the spots are colder than the photosphere by 1-2 thousand degrees (4500 K and below). As a result, against the background of the photosphere, the spots appear dark, the brightness of the core is 0.2-0.5 of the brightness of the photosphere, the brightness of the penumbra is about 80% of the photospheric. All sunspots have a strong magnetic field, reaching 5000 e for large spots. Usually, spots form groups that can be unipolar, bipolar, and multipolar in their magnetic field, i.e., containing many spots of different polarity, often united by a common penumbra. Groups of sunspots are always surrounded by faculae and flocculi, prominences, sometimes solar flares occur near them, and in the solar corona above them formations in the form of rays of helmets, fans are observed - all this together forms an active region in the north. The average annual number of observed sunspots and active regions, and also the average area occupied by them varies with a period of about 11 years. This is an average value, while the duration of individual cycles of solar activity ranges from 7.5 to 16 years (see Solar activity). The largest number of spots simultaneously visible on the surface of a solarium varies more than twice for different cycles. Mostly spots are found in the so-called. royal zones, extending from 5 to 30? heliographic latitude on both sides of the solar equator. At the beginning of the solar activity cycle, the latitude of the location of the spots is higher, at the end of the cycle it is lower, and at higher latitudes spots of a new cycle appear. Bipolar groups of sunspots are more often observed, consisting of two large sunspots - the head sunspot and the next sunspot, having opposite magnetic polarity, and several smaller sunspots. Headspots have the same polarity during the entire cycle of solar activity, these polarities are opposite in the northern and southern hemispheres of C. Apparently, the spots are depressions in the photosphere, and the density of matter in them is less than the density of matter in the photosphere at the same level .

In active solar regions, faculae are observed—bright photospheric formations that are visible in white light predominantly near the edge of the solar disk. Faculae usually appear before sunspots and exist for some time after they disappear. The area of ​​the torch sites is several times larger than the area of ​​the corresponding group of sunspots. The number of torches on the solar disk depends on the phase of the solar activity cycle. Faculae have maximum contrast (18%) near the edge of the C. disk, but not at the very edge. In the center of the C. disk, the faculae are practically invisible, and their contrast is very small. torches have a complex fibrous structure, their contrast depends on the wavelength at which observations are made. the temperature of the torches is several hundred degrees higher than the temperature of the photosphere, the total radiation from 1 cm2 exceeds the photospheric one by 3-5%. Apparently, the faculae rise somewhat above the photosphere. The average duration of their existence is 15 days, but can reach almost 3 months.

Chromosphere. Above the photosphere is a layer of the atmosphere called the chromosphere. Without special telescopes with narrow-band optical filters, the chromosphere is visible only during total solar eclipses as a pink ring surrounding the dark disk, in those minutes when the Moon completely covers the photosphere. Then one can observe the spectrum of the chromosphere, the so-called. flash spectrum. At the edge of the S. disk, the chromosphere appears to the observer as an uneven strip, from which individual teeth protrude - chromospheric spicules. The diameter of the spicules is 200-2000 km, the height is about 10,000 km, and the velocity of the plasma rise in the spicules is up to 30 km/sec. Up to 250,000 spicules exist simultaneously in the north. When observed in monochromatic light (for example, in the light of the line of ionized calcium 3934 A), a bright chromospheric network is visible on the C. disk, consisting of individual nodules - small nodules with a diameter of 1000 km and large ones with a diameter of 2000 to 8000 km. Large nodules are clusters of small ones. The size of the grid cells is 30-40 thousand km. It is believed that spicules are formed at the boundaries of the cells of the chromospheric grid. When observed in the light of the red hydrogen line 6563 A, a characteristic vortex structure is seen near sunspots in the chromosphere (Fig. 3). The density in the chromosphere decreases with increasing distance from the center C. The number of atoms in 1 cm3 varies from 1015 near the photosphere to 109 in the upper part of the chromosphere. The spectrum of the chromosphere consists of hundreds of emission spectral lines of hydrogen, helium, and metals. The strongest of them are the red line of hydrogen Na (6563 A) and the H and K lines of ionized calcium with a wavelength of 3968 A and 3934 A. The length of the chromosphere is not the same when observed in different spectra, lines: in the strongest chromospheric lines it can be traced up to 14 000 km above the photosphere. The study of the spectra of the chromosphere led to the conclusion that in the layer where the transition from the photosphere to the chromosphere occurs, the temperature passes through a minimum and, as the height above the base of the chromosphere increases, it becomes equal to 8-10 thousand K, and at an altitude of several thousand km it reaches 15 -20 thousand K. It has been established that in the chromosphere there is a chaotic (turbulent) movement of gas masses with velocities up to 15?103 m/s. . In the line Ha, dark formations called fibers are clearly visible. At the edge of the S. disk, the filaments protrude beyond the disk and are observed against the sky as bright prominences. Most often, filaments and prominences are found in four zones located symmetrically with respect to the solar equator: polar zones north of + 40? and south -40? heliographic latitude and low-latitude zones around? thirty? at the beginning of the solar activity cycle and 17? at the end of the cycle. The filaments and prominences of the low-latitude zones show a well-defined 11-year cycle; their maximum coincides with the sunspot maximum. In high-latitude prominences, the dependence on the phases of the solar activity cycle is less pronounced, the maximum occurs 2 years after the sunspot maximum. The filaments, which are quiet prominences, can reach the length of the solar radius and exist for several rotations of the north. The average height of prominences above the surface of the north is 30–50 thousand km, the average length is 200 thousand km, and the width is 5 thousand km. According to the studies of A. B. Severny, all prominences can be divided into 3 groups according to the nature of their movements: electromagnetic, in which movements occur along ordered curved trajectories - magnetic field lines; chaotic, in which disordered, turbulent movements predominate (velocities of the order of 10 km/sec); eruptive, in which the substance of an initially quiet prominence with chaotic motions is suddenly ejected at an increasing speed (reaching 700 km/sec) away from the north. The filaments, which are active, rapidly changing prominences, usually change strongly over several hours or even minutes. The form and nature of motions in prominences are closely related to the magnetic field in the chromosphere and the solar corona.

The solar corona is the outermost and most rarefied part of the solar atmosphere, extending over several (more than 10) solar radii. Until 1931, the corona could only be observed during total solar eclipses in the form of a silver-pearl glow around the S. disk covered by the Moon (see vol. 9, inset to pp. 384-385). The details of its structure stand out well in the crown: helmets, fans, coronal rays and polar brushes. After the invention of the coronagraph, the solar corona began to be observed outside of eclipses. The general shape of the corona changes with the phase of the solar activity cycle: in the years of minimum, the corona is strongly elongated along the equator; in years of maximum, it is almost spherical. In white light, the surface brightness of the solar corona is a million times less than the brightness of the center of the C disk. Its glow is formed mainly as a result of the scattering of photospheric radiation by free electrons. Almost all atoms in the corona are ionized. The concentration of ions and free electrons at the base of the corona is 109 particles per 1 cm3. The heating of the corona is carried out similarly to the heating of the chromosphere. The greatest release of energy occurs in the lower part of the corona, but due to the high thermal conductivity, the corona is almost isothermal - the temperature drops outward very slowly. The outflow of energy in the corona occurs in several ways. In the lower part of the corona, the main role is played by the downward transfer of energy due to heat conduction. Energy loss is caused by the escape of the fastest particles from the corona. In the outer parts of the corona, most of the energy is carried away by the solar wind, a stream of coronal gas whose velocity increases with distance from the north from a few km/sec at its surface to 450 km/sec at the Earth's distance. the temperature in the corona exceeds 106K. In active regions, the temperature is higher - up to 107K. Above the active regions, so-called. coronal condensations, in which the concentration of particles increases tenfold. Part of the radiation of the inner corona is the radiation lines of multiply ionized atoms of iron, calcium, magnesium, carbon, oxygen, sulfur, and other chemical elements. They are observed both in the visible part of the spectrum and in the ultraviolet region. Solar radiation in the meter range and X-rays are generated in the solar corona, which are amplified many times over in active regions. Calculations have shown that the solar corona is not in equilibrium with the interplanetary medium. Fluxes of particles propagate from the corona into interplanetary space, forming the solar wind. There is a relatively thin transitional layer between the chromosphere and the corona, in which the temperature rises sharply to values ​​characteristic of the corona. The conditions in it are determined by the flow of energy from the corona as a result of heat conduction. The transition layer is the source of most of the ultraviolet C radiation. The chromosphere, transition layer, and corona produce all of the observed C radio emission. In active regions, the structure of the chromosphere, corona, and transition layer changes. This change, however, is not yet well understood.

Solar flares. In active regions of the chromosphere, sudden and relatively short-term increases in brightness are observed, which are visible simultaneously in many spectral lines. These bright formations exist from several minutes to several hours. They are called solar flares (the former name is chromospheric flares). Flares are best seen in the light of the hydrogen line Ha, but the brightest ones are sometimes seen in white light. In the spectrum of a solar flare, there are several hundred emission lines of various elements, neutral and ionized. the temperature of those layers of the solar atmosphere that glow in the chromospheric lines (1-2) is ≈104 K, in higher layers - up to 107 K. The density of particles in the flare reaches 1013-1014 in 1 cm3. The area of ​​solar flares can reach 1015 m3. Typically, solar flares occur near rapidly developing sunspot groups with complex magnetic fields. They are accompanied by the activation of fibers and floccules, as well as the release of matter. During a flare, a large amount of energy is released (up to 1010-1011 J). It is assumed that the energy of a solar flare is initially stored in a magnetic field and then quickly released, which leads to local heating and acceleration of protons and electrons, causing further heating of the gas, its glow in different parts of the spectrum of electromagnetic radiation, the formation of a shock wave. Solar flares produce a significant increase in solar ultraviolet radiation and are accompanied by bursts of x-ray radiation (sometimes very powerful), bursts of radio emission, and the ejection of high-energy corpuscles up to 1010 eV. Sometimes bursts of X-ray emission are observed even without amplification of the glow in the chromosphere. Some solar flares (they are called proton flares) are accompanied by particularly strong streams of energetic particles - cosmic rays of solar origin. Proton flashes pose a danger to astronauts in flight, because Energetic particles, colliding with the atoms of the shell of the spacecraft, generate bremsstrahlung, x-rays and gamma radiation, sometimes in dangerous doses.

Influence of solar activity on terrestrial phenomena. S. is ultimately the source of all types of energy used by mankind (except atomic energy). This is the energy of wind, falling water, the energy released during the combustion of all types of fuel. The influence of solar activity on the processes occurring in the Earth's atmosphere, magnetosphere, and biosphere is very diverse (see Solar-Terrestrial Relations).

Instruments for the study of S. Observations of S. are carried out with the help of small or medium-sized refractors and large mirror telescopes, in which most of the optics are stationary, and the sun's rays are directed inside the horizontal or tower installation of the telescope using one (siderostat, heliostat) or two (coelostat ) moving mirrors (see Fig. to Art. Tower Telescope). In the construction of large solar telescopes, special attention is paid to high spatial resolution along the C disk. A special type of solar telescope, the non-eclipsing coronograph, has been created. Inside the coronagraph, the image of S. is eclipsed by an artificial "Moon" - a special opaque disk. In the coronagraph, the amount of scattered light is many times reduced, so that the outermost layers of the atmosphere C can be observed outside the eclipse. Solar telescopes are often equipped with narrow-band optical filters, which make it possible to observe in the light of a single spectral line. Neutral density filters with variable transparency along the radius have also been created, which make it possible to observe the solar corona at a distance of several radii C. Large solar telescopes are usually equipped with powerful spectrographs with photographic or photoelectric recording of spectra. A spectrograph may also have a magnetograph—an instrument for studying the Zeeman splitting and polarization of spectral lines and for determining the magnitude and direction of the magnetic field on the north. absorbed in the Earth's atmosphere led to the creation of orbital observatories outside the atmosphere, which make it possible to obtain spectra of solar radiation and individual formations on its surface outside the earth's atmosphere.