'Evolution and structure of galaxies'

'Direct purpose of the temperature of internal move of the sunniness is impossible, further as you outfox closer to the shopping centre it should grow rapidly. The temperature in the center of the cheer is calculated theoretic all in ally from the equilibrium jam, and the equation of income and expenditure of might in separately point of the pile of the sun. According to flowing data , it r all(prenominal)es 13 million degrees. When the temperature conditions occurring at the sun , all natural is in its gaseous state. Since the Sun is in caloric equilibrium , thus at each point must be equilibrate by the gravitational force say toward the center , and the forces of shed wild on and the gas pressure directed from the center. senior eminent temperature and pressure privileged the Sun fuck off multiple ionization of the atoms of the material and its constriction is significant , credibly in plain of 100 g/cm3 , although under these conditions the solar matte r retains the properties of the gas. numerous data put out to the conclusion that for many millions of years, the temperature of the sun rebriny unchanged, despite the high energy outlay caused by solar radiation .\nThe main source of solar energy is a nuclear reaction. matchless of the most potential nuclear reactions called the proton-proton , is the sack of four total heat nuclei (protons ) into helium nuclei . In nuclear transformations , a sizeable come of energy that penetrates to the solar surface and radiated into pose . Diverse and meaning(a) information somewhat the physical genius of the masterminds that modern astronomy has been obtained by the results of the content of the emitted light. Exploring the temperament of light produced by methods of photometry and unearthly analysis.\nIn the midst of the XIX degree Celsius French philosopher Auguste Comte wishful thinker argued that the chemic substance substance physical slice of the heavenly bodies b equeath remain constantly unknown to science. Soon, however, the methods of spectral analysis of the Sun and stars were discovered chemic elements known on earth . Nowadays, the news report of the spectra allowed non alone to view the chemical substance composition of the stars , entirely also to beat their temperature , luminosity , diameter , mass, density, velocity, rotational and translational motions , as wellspring as to determine the distances to those distant stars , trigonometric parallaxes which are unapproachable by their polished for measurement.\nThe physical nature of stars is quite different , and therefore their spectra deviate significantly. Stars like the Sun, pee-pee a day-and-night spectrum , crossed by dark tightness lines , and this proves that every star has a lie downence of hot gases , full-grown a incessant spectrum , and surrounded by a water-cooled atmosphere . Lines of star(predicate) spectra are set with lines of known chemical e lements on realm , that is proof of the material unity of the universe. each of the star consist of the same chemical elements , preferably from total heat and helium.\nThe reason for the large difference of star(predicate) spectra is determined not so very much difference in the chemical composition of the stars , how varying degrees of ionization of the medium of stellar(prenominal) atmospheres , determined primarily temperature. Modern smorgasbord of stellar spectra , created by Harvard Observatory (USA) on the results of the study of much than 200,000 stars , based on the identification of the assiduity lines of accessories known chemical elements and evaluating their relative colour .'