Sunny content. Sun, description, interesting facts, characteristics
The sun, the central body of the solar system, is a hot ball of gas. It is 750 times more massive than all other bodies in the solar system combined. That is why everything in the solar system can be roughly considered to revolve around the sun. The Sun outweighs the Earth by more than 330,000 times. A chain of 109 planets like ours could be placed on the solar diameter. The sun is the closest star to Earth and the only star whose disk is visible to the naked eye. All other stars that are light years away from us, even when viewed through the most powerful telescopes, do not reveal any details of their surfaces. Light from the Sun reaches us in 8 and a third minutes.
The sun rushes in the direction of the constellation Hercules in an orbit around the center of our Galaxy, overcoming more than 200 km every second. The Sun and the center of the Galaxy are separated by an abyss of 25,000 light years. A similar abyss lies between the Sun and the outskirts of the Galaxy. Our star is located near the galactic plane, not far from the border of one of the spiral arms.
The size of the Sun (1392,000 km in diameter) is very large by Earth standards, but astronomers, at the same time, call it a yellow dwarf - in the world of stars, the Sun does not stand out in anything special. However, in recent years, there are more and more arguments in favor of some unusualness of our Sun. In particular, the Sun emits less ultraviolet radiation than other stars of the same type. The sun has more mass than similar stars. In addition, these very similar stars to the Sun are seen in inconstancy, they change their brightness, that is, they are variable stars. The sun does not noticeably change its brightness. All this is not a reason for pride, but the basis for more detailed research and serious checks.
The radiation power of the Sun is 3.8 * 1020 MW. Only about one-half of a billionth of the Sun's total energy reaches Earth. Imagine a situation in which 15 standard apartments of 45 sq.m. flooded to the ceiling with water. If this amount of water is the entire output of the Sun, then the Earth will have less than a teaspoon. But it is thanks to this energy that the water cycle occurs on Earth, winds blow, life has developed and is developing. All the energy hidden in fossil fuels (oil, coal, peat, gas) is also originally the energy of the Sun.
The Sun radiates its energy in all wavelengths. But in a different way. 48% of the radiation energy is in the visible part of the spectrum, and the maximum corresponds to the yellow-green color. About 45% of the energy lost by the Sun is carried away by infrared rays. Gamma rays, X-rays, ultraviolet and radio radiation account for only 8%. However, the radiation of the Sun in these ranges is so strong that it is very noticeable at distances even hundreds of solar radii. The magnetosphere and the Earth's atmosphere protect us from the harmful effects of solar radiation.
The main characteristics of the Sun
| Weight | 1,989*10 30 kg |
| Mass (in Earth masses) | 332,830 |
| Radius at the equator | 695000 km |
| Radius at the equator (in Earth radii) | 108,97 |
| Average density | 1410 kg/m 3 |
| Sidereal day duration (rotation period) | 25.4 days (equator) - 36 days (poles) |
| Second space velocity (escape velocity) | 618.02 km/s |
| Distance from the center of the Galaxy | 25,000 light years |
| Period of revolution around the center of the Galaxy | ~200 Ma |
| The speed of movement around the center of the Galaxy | 230 km/s |
| Surface temperature | 5800–6000 K |
| Luminosity | 3,8 * 10 26 W(3.827*10 33 erg/sec) |
| Estimated age | 4.6 billion years |
| Absolute magnitude | +4,8 |
| Relative magnitude | -26,8 |
| Spectral class | G2 |
| Classification | yellow dwarf |
|
Chemical composition (by number of atoms) |
|
| Hydrogen | 92,1% |
| Helium | 7,8% |
| Oxygen | 0,061% |
| Carbon | 0,030% |
| Nitrogen | 0,0084% |
| Neon | 0,0076% |
| Iron | 0,0037% |
| Silicon | 0,0031% |
| Magnesium | 0,0024% |
| Sulfur | 0,0015% |
| Other | 0,0015% |
The sun is the center of our planetary system, its main element, without which there would be neither the Earth nor life on it. People have been observing the star since ancient times. Since then, our knowledge of the luminary has expanded significantly, enriched with numerous information about the movement, internal structure and nature of this cosmic object. Moreover, the study of the Sun makes a huge contribution to understanding the structure of the Universe as a whole, especially those of its elements that are similar in essence and principles of "work".
Origin
The sun is an object that has existed, by human standards, for a very long time. Its formation began about 5 billion years ago. Then there was a vast molecular cloud in place of the solar system. Under the influence of gravitational forces, eddies began to appear in it, similar to terrestrial tornadoes. In the center of one of them, matter (mostly hydrogen) began to condense, and 4.5 billion years ago a young star appeared here, which, after another long period of time, received the name of the Sun. Planets gradually began to form around it - our corner of the Universe began to acquire its usual modern man view.
yellow dwarf
The sun is not a unique object. It belongs to the class of yellow dwarfs, relatively small main sequence stars. The term of "service" released to such bodies is approximately 10 billion years. By the standards of space, this is quite a bit. Now our luminary, one might say, is in the prime of life: not yet old, no longer young - there is still half a life ahead.
A yellow dwarf is a giant ball of gas whose light source is thermonuclear reactions occurring in the core. In the red-hot heart of the Sun, the process of transformation of hydrogen atoms into atoms of heavier chemical elements is continuously going on. While these reactions are taking place, the yellow dwarf emits light and heat.
death of a star
When all the hydrogen burns out, it will be replaced by another substance - helium. This will happen in about five billion years. The exhaustion of hydrogen marks the onset of a new stage in the life of a star. She will turn into a red giant. The sun will begin to expand and occupy all space up to the orbit of our planet. At the same time, its surface temperature will decrease. In about another billion years, all the helium in the core will turn into carbon, and the star will shed its shells. In place of the solar system, the surrounding Takov will also remain. life path all the stars like our sun.
Internal structure
The mass of the Sun is huge. It accounts for approximately 99% of the mass of the entire planetary system.
About forty percent of this number is concentrated in the nucleus. It occupies less than a third of the solar volume. The core diameter is 350 thousand kilometers, the same indicator for the entire star is estimated at 1.39 million km.
The temperature in the solar core reaches 15 million Kelvin. Here is the most high rate density, other inner regions of the Sun are much more rarefied. Under such conditions, thermonuclear fusion reactions take place, providing energy for the luminary itself and all its planets. The core is surrounded by a radiative transport zone, followed by a convection zone. In these structures, energy moves towards the surface of the Sun by two different processes.
From the nucleus to the photosphere
The core borders on the radiative transmission zone. In it, the energy propagates further through the absorption and emission of light quanta by the substance. This is a rather slow process. It takes thousands of years for light quanta to travel from the nucleus to the photosphere. As they advance, they move forward and backward, and reach the next zone transformed.
From the zone of radiative transfer, energy enters the region of convection. Here the movement takes place according to somewhat different principles. The solar matter in this zone is mixed like a boiling liquid: the hotter layers rise to the surface, while the cooled ones sink deeper. Gamma quanta formed in the nucleus, as a result of a series of absorptions and radiations, become quanta of visible and infrared light.
Behind the convection zone is the photosphere, or the visible surface of the Sun. Here again the energy moves by means of radiant transfer. Hot streams reaching the photosphere from the underlying region create a characteristic granular structure, which is clearly visible in almost all photographs of the star.
outer shells
Above the photosphere is the chromosphere and the corona. These layers are much less bright, so they are visible from Earth only during a total eclipse. Magnetic flares on the Sun occur precisely in these rarefied regions. They, like other manifestations of the activity of our luminary, are of great interest to scientists.
Flashes are caused by the generation of magnetic fields. The mechanism of such processes requires careful study, also because solar activity leads to perturbation of the interplanetary medium, and this has a direct impact on geomagnetic processes on Earth. The impact of the luminary is manifested in a change in the number of animals, almost all systems of the human body react to it. The activity of the Sun affects the quality of radio communication, the level of ground and surface water planet, climate change. Therefore, the study of the processes leading to its increase or decrease is one of the most important tasks of astrophysics. To date, not all questions related to solar activity have been answered.
Earth observation
The sun affects all living beings on the planet. The change in the length of daylight hours, the increase and decrease in temperature directly depend on the position of the Earth relative to the star.
The movement of the Sun across the sky is subject to certain laws. The luminary moves along the ecliptic. This is the name of the annual path that the Sun travels. The ecliptic is the projection of the plane of the earth's orbit onto the celestial sphere.
The movement of the luminary is not difficult to notice if you watch it for a while. The point at which the sunrise occurs is moving. The same is true for sunset. When winter comes, the Sun is much lower at noon than in summer.
The ecliptic passes through the zodiac constellations. Observation of their displacement shows that at night it is impossible to see those celestial drawings in which the luminary is currently located. It turns out to admire only those constellations where the Sun stayed about six months ago. The ecliptic is inclined to the plane of the celestial equator. The angle between them is 23.5º.
Declension change
On the celestial sphere is the so-called point of Aries. In it, the Sun changes its declination from south to north. The luminary reaches this point every year on March 21st. The sun rises much higher in summer than in winter. Related to this is the change temperature regime and daylight hours. When winter comes, the Sun in its movement deviates from the celestial equator to the North Pole, and in summer to the South.
Calendar
The luminary is located exactly on the line of the celestial equator twice a year: on the days of the autumn and spring equinoxes. In astronomy, the time it takes for the Sun to travel from and back to Aries is called the tropical year. It lasts approximately 365.24 days. It is the duration that underlies It is used today almost everywhere on Earth.
The sun is the source of life on earth. The processes taking place in its depths and on the surface have a tangible impact on our planet. The meaning of the luminary was already clear in ancient world. Today we know quite a lot about the phenomena occurring on the Sun. The nature of individual processes has become clear thanks to advances in technology.
The Sun is the only star close enough to be directly studied. Data about the star help to understand the mechanisms of "work" of other similar space objects. However, the Sun still holds many secrets. They just have to be explored. Phenomena such as the rising of the Sun, its movement across the sky, and the heat it radiates were once also mysteries. The history of the study of the central object of our piece of the Universe shows that over time, all the oddities and features of the star find their explanation.
Sooner or later, every earthling asks this question, because the existence of our planet depends on the Sun, it is its influence that determines all the most important processes on Earth. The sun is a star.
There are a number of criteria according to which a celestial body can be classified as planets or stars, and the Sun corresponds precisely to those characteristics that are inherent in stars.
The main characteristics of stars
First of all, a star differs from a planet in its ability to radiate heat and light. Planets, on the other hand, only reflect light, and are essentially dark celestial bodies. The surface temperature of any star is much higher than the surface temperature.
The average temperature of the surface of stars can range from 2 thousand to 40 thousand degrees, and the closer to the core of the star, the higher this temperature. Near the center of a star, it can reach millions of degrees. The temperature on the surface of the Sun is 5.5 thousand degrees Celsius, and inside the core it reaches 15 million degrees.
Stars, unlike planets, do not have orbits, while any planet moves in its orbit relative to the luminary that forms the system. In the solar system, all the planets, their satellites, meteorites, comets, asteroids and cosmic dust move around the sun. The sun is the only star in the solar system. 
Any star with its mass exceeds even the largest planet. The Sun accounts for almost the entire mass of the entire solar system - the mass of the star is 99.86% of the total volume.
The diameter of the Sun at the equator is 1 million 392 thousand kilometers, which is 109 times the equatorial diameter of the Earth. And the mass of the sun is approximately 332,950 times the mass of our planet - it is 2x10 to the 27th power of tons.
Stars are made up mostly of light elements, unlike planets, which are made up of solid and light particles. The sun is 73% by mass and 92% by volume hydrogen, 25% by mass and 7% by volume is helium. A very small proportion (about 1%) is accounted for by an insignificant amount of other elements - these are nickel, iron, oxygen, nitrogen, sulfur, silicon, magnesium, calcium, carbon and chromium.
One more hallmark stars are nuclear or thermonuclear reactions occurring on its surface. It is these reactions that occur on the surface of the Sun: some substances are rapidly transformed into others with the release of a large amount of heat and light.
It is the products of thermonuclear reactions occurring on the Sun that give the Earth the necessary for it. But on the surface of the planets, such reactions are not observed.
Planets often have satellites, some celestial bodies even have several. A star cannot have satellites. Although there are also planets without satellites, therefore this sign can be considered indirect: the absence of a satellite is not yet an indicator that a celestial body is a star. To do this, the other listed features must also be available.
The sun is a typical star
So, the center of our solar system - the Sun - is classic star: it is much larger and heavier than even the largest planets, 99% consists of light elements, radiates heat and light during thermonuclear reactions occurring on its surface. The sun does not have an orbit and satellites, but eight planets and other celestial bodies that make up the solar system revolve around it.
The sun for a person observing it from the Earth is not a small point, like other stars. We see the Sun as a large bright disk because it is close enough to the Earth.
If the Sun, like other stars visible in the night sky, moved away from our planet for trillions of kilometers, we would see it as the same tiny star that we see now other stars. On the scale of space, the distance between the Earth and the Sun - 149 million kilometers - is not considered large.
According to scientific classification, the Sun belongs to the category of yellow dwarfs. Its age is about five billion years, and it shines with a bright and even yellow light. Why the light of the sun? This is due to its temperature. To understand how the color of stars is formed, we can recall the example of red-hot iron: first it turns red, then it acquires an orange tone, then yellow. 
If iron could be heated further, it would turn white and then blue. Blue stars are the hottest: the temperature on their surface is more than 33 thousand degrees.
The sun belongs to the category of yellow stars. Interestingly, within seventeen light years, where about fifty star systems are located, the Sun is the fourth brightest star.
The sun
The sun is the closest star to us. The distance to it by astronomical standards is small: only 8 minutes is the light from the Sun to the Earth. This is a star that was formed after supernova explosions, it is rich in iron and other elements. Near which such a planetary system was able to form, on the third planet of which - Earth - life arose. Five billion years is the age of our Sun. The sun is the star around which our planet revolves. The average distance from the Earth to the Sun, i.e. the semi-major axis of the Earth's orbit is 149.6 million km = 1 AU. (astronomical unit). The sun is the center of our planetary system, which, in addition to it, includes 9 large planets, several dozen satellites of the planets, several thousand asteroids (minor planets), comets, meteoroids, interplanetary dust and gas. The sun is a star that shines fairly evenly over millions of years, as proven by modern biological studies of the remnants of blue-green algae. If the temperature of the Sun's surface were to change by just 10%, life on Earth would probably be wiped out. Our star evenly and calmly radiates the energy so necessary to sustain life on Earth. The size of the Sun is very large. So, the radius of the Sun is 109 times, and the mass is 330,000 times greater than the radius and mass of the Earth. The average density is low - only 1.4 times the density of water. The sun does not rotate like a solid body, the speed of rotation of points on the surface of the sun decreases from the equator to the poles.
· Weight: 2*10 30kg;
· Radius: 696,000 km;
· Density: 1.4 g/cm 3 ;
· Surface temperature:+5500 С;
· Period of rotation relative to the stars: 25.38 Earth days;
· Distance from Earth (average): 149.6 million km;
· Age: about 5 billion years;
· Spectral class: G2V;
· Luminosity: 3.86*10 26W, 3.86*10 23KW
The position of the sun in our galaxy
The Sun is located in the plane of the Galaxy and is removed from its center by 8 kpc (26000 light years) and from the plane of the Galaxy by about 25 pc (48 light years). In the region of the Galaxy where our Sun is located, the stellar density is 0.12 stars per pc3. sun (and solar system) moves at a speed of 20 km / s towards the border of the constellations Lyra and Hercules. This is due to local motion within nearby stars. This point is called the apex of the motion of the Sun. The point on the celestial sphere opposite to the apex is called the anti-apex. At this point, the directions of proper velocities of the stars closest to the Sun intersect. The motions of the stars closest to the Sun occur at a low speed; this does not prevent them from participating in circulation around the galactic center. The solar system is involved in rotation around the center of the Galaxy at a speed of about 220 km/s. This movement occurs in the direction of the constellation Cygnus. The period of revolution of the Sun around the galactic center is about 220 million years.
The internal structure of the Sun
The sun is a hot ball of gas, the temperature in the center of which is very high, so much so that nuclear reactions can occur there. At the center of the Sun, the temperature reaches 15 million degrees, and the pressure is 200 billion times higher than at the surface of the Earth. The sun is a spherically symmetrical body in balance. Density and pressure rapidly increase in depth; the increase in pressure is explained by the weight of all overlying layers. At each internal point of the Sun, the condition of hydrostatic equilibrium is satisfied. Pressure at any distance from the center is balanced by gravitational attraction. The radius of the Sun is approximately 696,000 km. In the central region with a radius of about a third of the solar core, nuclear reactions take place. Then, through the zone of radiative transfer, energy is transferred by radiation from the inner regions of the Sun to the surface. Both photons and neutrinos are born in the zone of nuclear reactions in the center of the Sun. But if neutrinos interact very weakly with matter and instantly leave the Sun freely, then photons are repeatedly absorbed and scattered until they reach the outer, more transparent layers of the Sun's atmosphere, which is called the photosphere. While the temperature is high - more than 2 million degrees - the energy is transferred by radiant heat conduction, that is, by photons. The opacity zone due to the scattering of photons by electrons extends approximately to a distance of 2/3R of the solar radius. As the temperature decreases, the opacity increases greatly, and the diffusion of photons lasts about a million years. Approximately at a distance of 2/3R is the convective zone. In these layers, the opacity of matter becomes so great that large-scale convective motions arise. Here begins convection, that is, the mixing of hot and cold layers of matter. The rise time of a convective cell is relatively short - several tens of years. Acoustic waves propagate in the solar atmosphere, similar to sound waves in air. In the upper layers of the solar atmosphere, waves that have arisen in the convective zone and in the photosphere transfer part of the mechanical energy of convective movements to the solar matter and heat the gases of the subsequent layers of the atmosphere - the chromosphere and corona. As a result, the upper layers of the photosphere with a temperature of about 4500 K are the "coldest" on the Sun. Both deep into and up from them, the temperature of the gases increases rapidly. Every solar atmosphere is constantly fluctuating. It propagates both vertical and horizontal waves with lengths of several thousand kilometers. The oscillations are resonant in nature and occur with a period of about 5 minutes. The inner parts of the Sun rotate faster; the core rotates especially fast. It is the features of such rotation that can lead to the emergence of the magnetic field of the Sun.
The modern structure of the Sun arose as a result of evolution (Fig. 9.1, a, b). The observed layers of the Sun are called its atmosphere. Photosphere- its deepest part, and the deeper, the hotter the layers. In a thin (about 700 km) layer of the photosphere, the observed solar radiation arises. In the outer, colder layers of the photosphere, light is partially absorbed - against the background of a continuous spectrum, dark fraunhofer lines. The granularity of the photosphere can be observed through a telescope. Little bright spots granules(up to 900 km in size) - surrounded by dark gaps. This convection that occurs in the inner regions causes movements in the photosphere - in the granules, hot gas breaks out, and between them it sinks. These movements also propagate to the higher layers of the Sun's atmosphere - chromosphere And crown. Therefore, they are hotter than the upper part of the photosphere (4500 K). The chromosphere can be observed during eclipses. visible spicules- reeds of the condensed gas. The study of the spectra of the chromosphere shows its heterogeneity, the gas mixing occurs intensively, and the temperature of the chromosphere reaches 10,000 K. Above the chromosphere is the rarest part of the solar atmosphere - the corona, which constantly fluctuates with a period of 5 minutes. Density and pressure build up rapidly inward, where the gas is highly compressed. The pressure exceeds hundreds of billions of atmospheres (10 16 Pa), and the density is up to 1.5 10 5 kg/m. The temperature also rises strongly, reaching 15 million K.
Magnetic fields play an essential role on the Sun, since the gas is in the plasma state. With an increase in the field strength in all layers of its atmosphere, solar activity increases, manifesting itself in flares, which in the years of maximum are up to 10 per day. Flares with a size of about 1000 km and a duration of about 10 min usually occur in neutral regions between sunspots of opposite polarity. During a flash, energy is released equal to the energy of an explosion of 1 million megaton hydrogen bombs. Radiation at this time is observed both in the radio range and in the X-ray. Energetic particles appear - protons, electrons and other nuclei that make up solar cosmic rays.
Sunspots move across the disk; noticing this, Galileo concluded that it rotates around its axis. Observations of sunspots have shown that the Sun rotates in layers: near the equator the period is about 25 days, and near the poles - 33 days. The number of sunspots fluctuates over 11 years from the largest to the smallest. The so-called Wolf numbers are taken as a measure of this spot-forming activity: W= 10g+f, here g is the number of spot groups, f is the total number of spots on the disk. With no stains W= 0, with one spot - W= 11. On average, a stain lives for almost a month. The spots are hundreds of kilometers in size. Spots are usually accompanied by a group of light stripes - torches. It turned out that strong magnetic fields (up to 4000 oersteds) are observed in the region of the spots. The fibers visible on the disk are named prominences. These are masses of denser and colder gas rising hundreds and even thousands of kilometers above the chromosphere.
In the visible region of the spectrum, the Sun absolutely dominates on Earth over all other celestial bodies, its brilliance is 10 10 times greater than that of Sirius. In other ranges of the spectrum, it looks much more modest. Radio emission comes from the Sun, the power is the same as the radio source Cassiopeia A; there are only 10 sources in the sky 10 times weaker than it. It was noticed only in 1940 by military radar stations. The analysis shows that short-wavelength radio emission originates near the photosphere, and at meter wavelengths it is generated in the solar corona. A similar picture in terms of radiation power is also observed in the X-ray range - only for six sources is it weaker by an order of magnitude. The first X-ray photographs of the Sun were obtained in 1948 with the help of the equipment located on a high-altitude rocket. It has been established that the sources are associated with active regions on the Sun and are located at altitudes of 10–1,000,000 km above the photosphere; the temperature in them reaches 3–6 million K. An X-ray flare usually follows an optical flare with a delay of 2 min. X-rays come from the upper layers of the chromosphere and the corona. In addition, the Sun emits streams of particles - corpuscle. Solar corpuscular streams have a great impact on the upper layers of the atmosphere of our planet.
Origin of the Sun
The sun originated from an infrared dwarf, which in turn originated from a giant planet. The giant planet even earlier originated from an icy planet, and that one from a comet. This comet originated at the periphery of the Galaxy in one of the two ways that comets occur at the periphery of the solar system. Either the comet, from which the Sun originated many billions of years later, was formed during the crushing of larger comets or icy planets during their collision, or this comet passed into the Galaxy from intergalactic space ..
Hypothesis about the origin of the Sun from a gaseous nebula
So, according to the classical hypothesis, the solar system arose from gas and dust
a cloud made up of 98% hydrogen. In the initial epoch, the density of matter in this nebula was very low. Separate "pieces" of the nebula moved relative to each other at random speeds (about 1 km/s). In the process of rotation, such clouds first turn into flat disc-shaped clusters. Then, in the process of rotation and gravitational compression, the concentration of matter with the highest density occurs in the center. As I. Shklovsky writes, “as a result of the existence of a“ magnetic ”connection between the disk separated from the protostar and its main mass, due to the tension of the lines of force, the rotation of the protostar will slow down, and the disk will begin to go outward in a spiral. Over time, the disk will be smeared due to friction ", and part of its substance will turn into planets, which will thus "take away" with them a significant part of the moment ".
Thus, suns form in the center of the cloud, and planets along the periphery.
There are several hypotheses about the similar formation of suns and planets. Some tend to associate this process with external cause- a flash in the neighborhood of stars. So, S. K. Vsekhsvyatsky believes that a star flared up near our gas and dust cloud 5 billion years ago at a distance of 3.5 light years. This led to the heating of the gas and dust nebula, the formation of the Sun and planets. The same opinion is shared by Clayton (for the first time this idea was expressed in 1955 by the Estonian astronomer Epik). According to Clayton, the contraction that formed the Sun was caused by a supernova which, by exploding, gave motion to the interstellar matter and, like a broom, pushed it ahead of itself; this happened until, due to the force of gravity, a stable cloud was formed, which continued to contract, turning its own compression energy into heat. All this mass began to heat up, and in a very short time (tens of millions of years) the temperature inside the cloud reached 10-15 million degrees. By this time, thermonuclear reactions were in full swing and the compression process was over. It is generally accepted that it was at this “moment”, from four to six billion years ago, that the Sun was born.
This hypothesis, which has a small number of supporters, was confirmed as a result of a study in 1977 by an American scientist from the California Institute of Technology "Allende meteorite", found in a deserted region of northern Mexico. An unusual combination of chemical elements was found in it. The excess presence of calcium, barium and neodymium in it indicates that they fell into a meteorite during a supernova explosion in the neighborhood of our solar system. This outbreak occurred less than 2 million years before the formation of the solar system. This date was obtained from the results of determining the age of the meteorite using the aluminum-26 radioisotope, which has a half-life of T = 0.738 million years.
Other scientists, and most of them, believe that the process of the formation of the Sun and planets occurred as a result of the natural development of a gas and dust cloud during its rotation and compaction. According to one of these hypotheses, it is believed that the condensation of the Sun and planets occurred from a hot gas nebula (according to I. Kant and P. Laplace), and according to another, from a cold gas and dust cloud (according to O. Yu. Schmidt). Subsequently, the cold-onset hypothesis was developed by academicians V. G. Fesenkov, A. P. Vinogradov, and others.
The most consistent supporter of the hypothesis of the formation of the solar system from the primary "solar" nebula is the American astronomer Cameron. It links the formation of stars and planetary systems into a single process. Supernova explosions in the process of condensation of clouds of the interstellar medium due to their gravitational instability are, as it were, "stimulators" of the process of star formation.
However, none of these hypotheses fully satisfies scientists, since it is impossible to explain with their help all the nuances associated with the origin and development of the solar system. During the formation of planets from a "hot" beginning, it is believed that on early stage they were high-temperature homogeneous bodies consisting of liquid and gas phases. Subsequently, when such bodies cooled, iron cores first separated from the liquid phase, then the mantle was formed from sulfides, iron oxides and silicates. The gas phase led to the formation of the atmosphere of the planets and the hydrosphere on Earth.
etc.................
Think you know everything about our star? We present to you Interesting Facts about the sun. Some, you probably already know, while others will be completely unexpected for you.
List of the most interesting facts
1. Sun and solar system
We live on the planet and think that the Earth is an equal member of the solar system. The reality is that the mass of the central star is 99.8% of the mass of the solar system. And most of the remaining 0.2% comes to Jupiter. Thus, the mass of the Earth is hundredths of the mass of the solar system.
2. Our star is mostly hydrogen and helium.
The sun is 74% hydrogen and 24% helium. The remaining 2% includes a small amount of iron, nickel, oxygen. In other words, the solar system is mostly made up of hydrogen.
3. The sun is very bright
We know that there are amazingly large and bright stars, such as Sirius or Betelgeuse. But they are incredibly far away. Our own luminary is a relatively bright star. If you could take the 50 closest stars within 17 light years of Earth, then it would be the 4th brightest star.
4. The sun is huge but tiny at the same time.
Its diameter is 109 times larger than the Earth's, 1300 thousand Earths could fit inside it. But there are much larger stars whose diameter would almost reach the orbit of Saturn if the star were placed inside the solar system.
5. Average age 4.5 billion years
Astronomers believe that our star formed about 4590 million years ago. After about 5 billion years, it will enter the stage of a red giant, and swell, then, having shed its outer layers, it will turn into a white dwarf.
6. The sun has a layered structure
Although our luminary looks like a burning fireball, it actually has an internal structure divided into layers. The visible surface, called the photosphere, is heated to about 6,000 degrees Kelvin. Below it is a convection zone, where heat slowly moves from the center to the surface, and the cooled stellar matter falls down. This area starts at a distance of 70% of the radius. Below the convection zone is the radiation belt. In this zone, heat is transferred through radiation. The core extends from the center to a distance of 0.2 solar radii. This is the place where the temperature reaches 13.6 million degrees Kelvin, and hydrogen molecules fuse into helium.
7. The sun can destroy all life on Earth
The sun is actually slowly warming up. It gets 10% brighter every billion years. For the entire billion years, the heat will be so intense that liquid water will not be able to exist on the surface of the Earth. Life on Earth will disappear forever. Bacteria will be able to live underground, but the surface of the planet will be scorched and uninhabitable. In 7 billion years, it will turn into a red giant, and before it expands, the Sun will pull the Earth towards itself and destroy the entire planet.
8. Its different parts rotate at different speeds
Unlike the planets, the Sun is a huge sphere of hydrogen. Because of this, different parts rotate at different speeds. You can see how fast the surface is rotating by tracking the movement of the spots across the surface. A rotation at the equator takes 25 days, while at the poles, a full rotation can take 36 days.
9. The outer atmosphere is hotter than its surface
The surface has a temperature of 6000 degrees Kelvin. But this is much less than the temperature of the star's atmosphere. Above the surface there is a region of the atmosphere called the chromosphere, its temperature can reach 100,000 K. Even more distant regions, called the corona, reach temperatures of 1 million K.
10 There Are Spacecraft Studying It Right Now
The most famous spacecraft sent for observation was launched in December 1995 and is called SOHO. SOHO is constantly watching our luminary. In 2006, two vehicles of the STEREO mission were launched. The two craft were designed to view activity from two different vantage points, providing 3D models of our star, and allowing astronomers to more accurately predict space weather.
