Sunday, October 23, 2011

The sun

The description

 The sun is the centre, a dominating star in our Solar system. And though this star plays a huge role for our planetary system, on the scale of the Universe at this star enough average physical parametres which are up to standard of a star-dwarf. The sun is an enormous sphere from plasma (the gas sated with ions) which basically consists of hydrogen and helium.

The structure of the Sun known as on supervision, and as result of construction of theoretical models, layered. In the centre the kernel in which chain thermonuclear reactions proceed is located. Round a kernel there are sites circular konvektsii and radiating carrying over. The most external cover is a photosphere, chromosphere and a crown.

Though a kernel it is impossible to make out directly, physical parametres in its bowels are known with a fine precision. In a kernel the 15 million temperature ok remains and density about 100/sm3 Such conditions allow to proceed to nuclear processes in which course hydrogen turns to helium during the reaction known as “a proton – a proton”. During this reaction the energy large quantity is liberated. At formation of one kernel of helium 6 hundred billion calories is allocated approximately.

The energy arising during thermonuclear transformations, allows the Sun to support the existence and not kollapsirovat under the influence of gravity of own weight. Our star is in a balance condition between two these forces about 4,5 billion years, and it is supposed that the hydrogen which is in a kernel, will provide its stability for long enough period.

The unique particles made during nuclear processes on the Sun to which manage not to co-operate with a matter, are nejtrino which transfer the information "firsthand" from bowels of our star.

In the course of the nuclear reactions resulting in the heart of the Sun, the big set of gamma beams is liberated. They aspire to escape for star limits, thus "having bared" a kernel. But existence of the top layer brakes their exit in external open spaces. Thus, gamma beams many times make interaction with a matter meeting on their trajectory and are repeatedly radiated further. The layer of our star in which these events take place, is called as area of radiating carrying over as photons here are multiplied because of "the radiation", one of three probable ways of distribution, namely – electromagnetic radiation (other two: konvektsija and conductivity).

Processes vpityvanija and secondary radiation are so strong that energy let out in the form of gamma radiation to leave on a surface, millions years are necessary. It means that the sunlight reaching us now was born from heat which has appeared in its bowels millions years ago.

In a current of processes of colliding of a gamma particle lose an energy part. In a certain point their energy, at first rather high, becomes equal to thermal energy of a solar matter. From this point on prevailing there is a mechanism konvektsii. Unlike area of radiating carrying over where energy is transferred by gamma beams, in konvektivnoj to a zone radiation and a matter have equal temperature, and the energy most part is transferred here by a matter.

The higher limit konvektivnoj a zone looks like the small granules changing within several minutes, so-called rice grains which are visible on a solar surface even through a telescope with modest enough possibilities.

The external layer of the centre of our system consists of photosphere and chromosphere. The photosphere which is a visible surface of the Sun, has depth about 500 km and temperature nearby 6000 oК.

The sun

At photosphere there is a considerable activity first of all in the form of dark zones, so-called solar stains. Behind them conducted supervision during antique times, however, despite it, till now their present nature is a little known.
Later, with proprocession of some time, Galilej “again has opened” stains on the Sun though this "opening" and is long it was challenged by Jesuit Christopher Shejnerom. Supervision over solar stains among other, has led to a collapse oristotelevsko-ptolemeevskoj to Universe model on which shone are ideal inseparable spheres. Regular supervision over solar stains have been begun approximately in the middle of a XVIII-th century.
What kind solar stains from outside have. Solar stains seem dark, but not that they really black. Simply they colder in comparison with surrounding them photospheres. Round the most dark area of a stain, a so-called shade, there is an intermediate light zone, a so-called penumbra. The shade temperature is approximately equal to 4,3-4,8 thousand oК, that is approximately on 1000-1500 ° below photosphere temperature. And here heat of a penumbra is equal approximately 5400-5500 oК. Intensity of light in a shade makes approximately 32 % from intensity of a luminescence of photosphere, and a penumbra – 80 %. It seems that decrease in temperature in stains is connected with the strong magnetic fields opened by George Elleri Hejlom in 1908 and registered in this area. Such fields disturb constant konvektivnomu to movement of the solar matter being in a condition of plasma and trying from within vylezt on a surface.
Solar stains can reach to such impressive (from 7 thousand 50 thousand in km) parametres that them probably to make out without special devices, though, certainly, through protective filters. They can appear on one, but usually, are formed by groups. Besides, stains move on the Sun surface: as in itself, and is much stronger because of the non-uniform reference of the Sun. Without being firm space object, it rotates faster in the zones nearest to the middle (where the rotation period makes 27 sut), than in polar sites (nearby 31 sut).
It is known, at least, from a XVIII-th century that intensity and frequency of stains cyclically vary with periodicity approximately 11 years. That is during this period on a solar disk the quantity of stains grows, reaching a maximum. Then it decreases, reaching gradually starting level. Average duration of a cycle (11,07 years) fluctuates within the limits from 7 till 15 years.
In the minimum phase frequently happens that on the Sun of a stain are absent in general, sometimes even long enough time (days or even weeks). And here in the maximum phases it is possible to observe without effort 10-20 groups, and also separate stains. Last maximum of a cycle was in the beginning of 2001.
And though it is not absolutely clear yet, but, seemingly, that the solar cycle grows out of interaction between a magnetic field of the Sun and zones konvektsii on a surface.
Long enough irregular periods when there is an impression are historically fixed that solar activity has stiffened completely and definitively. The nearest to us on time such period is known in scientific organisation, as “a minimum of Maundera”, begun in 30th years of a XVII-th century and lasted about three quarters of the century.
Except solar stains, solar activity is expressed and in other displays. So, for example, flashes, the powerful explosions covering extensive areas of a blanket of the Sun, especially near to stains. Duration of flashes usually makes tens minutes, and at times reaches about one hour. The phase in which the energy most part is allocated, corresponds with the greatest brightness and lasts few minutes. This rather fast phase is preceded by""preparation"for very big emission of x-ray and ultra-violet beams and special radiation of a hydrogen spectrum, so-called lines the N-alpha, a characteristic red shade typical for chromosphere. Except these emissions of photons and particles, a considerable quantity of the radio-waves proceeds, similar process is easy for simulating on the Earth. After some hours the particles accelerated by flash, reach our planet, generating polar light of appreciable force and the electromagnetic storms leading to malfunctions in telecommunication networks and equipment in global scales.
Flashes – not the unique incident of explosive type meeting on a surface of our star. Besides them, are known still so-called protuberantsy. These are less entertainment, events; it also explosions, but much more silent. Nevertheless, in many cases protuberantsy associate with flashes. The cycle protuberantsa usually occurs much less impulsively, than flashes. Also that most of all amazes the spectator, this impressive show of ejection of a matter. Their form is to a greater or lesser extent similar to an arch ascending over chromosphere. There are various types protuberantsev, to duration from pair minutes about several days.

The sun

Over photosphere as it was already marked, the chromosphere in which the temperature happens to 10 thousand oК is located. It is found out in the form of a bright ring of a pinkish shade round the Sun during full solar eclipses. Researches of a solar disk by means of suitable equipment which gives the chance to allocate light which is let out by chromosphere, show that the Sun surface as if is covered by threads of the heated gas. These are the small emissions of hydrogen directed upwards on type protuberantsev. Such emissions of gas are called "spikulami" and can reach in height more than 10 thousand in km. They can last about 5 minutes
And at last, the chromosphere flows in the most external part of the Sun – a crown. Close the chromosphere is improbably bright and is not uniform, in interplanetary space it has more pale appearance.
Crown temperature extremely high – millions degrees. Factors of it are not up to the end investigated yet.
During a usual cycle of solar activity the crown grows, becoming more and more symmetric, getting a sharp teeth and deep hollows. The greatest uniformity meets during the periods of a maximum of solar activity whereas during the minimum periods of solar activity the crown seems flattened on equator, and on poles – almost disappears.
The sun liberates a large quantity of the charged particles of which the continuous stream aspiring to most okrainnym to the zones of our planetary system is formed. Such streams of particles have received the name “a solar wind”.
At a solar wind speed is equal about 400 km/s, and density – 10 particles on one see cubic, that is in billion billions times less, than density of a terrestrial air cover.
The solar wind consists basically of protons and elektronov, however in it there are also kernels of helium and other elements.
The solar wind not infinitely wanders in interstellar space because particles anyhow enter interaction with the interstellar environment – the rarefied gas and lose the kinetic energy. The area where the solar wind comes to an end, is called "geliopauzoj" and designates limits “influence spheres” the Sun.
Sun characteristics:
Weight (the Earth = 1) – 332 946
Volume (the Earth = 1) – 1 303 600
Average density – 1,41 g/sm3
The rotation period (concerning equator) – 27 days
Equatorial diameter – 1 392 000 km
Kernel temperature – 14 000 000 oK
Surface temperature – 5770 oK
Kernel density – about 100 g/sm3
Capacity of let out radiation – 3,86 * 1023 kw
Force of an attraction on a surface (the Earth = 1) – 27,9
Cycle time round the Galaxy centre – 225 million years

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