Stars are gaseous stars that produce their own light and energy, (various radiations such as visible light, ultraviolet rays, gamma rays, and electromagnetic energies).
They are agglomerations of matter in plasma and gaseous state, which is in a continuous process of collapse (caused by gravitational force) and expansion (by strong thermonuclear explosions and other forces) that keep the matter of the stars in a state of equilibrium hydrostatic. The closest star to the planet earth is our sun, approximately at a distance of 149,600,000 kilometers (8 light minutes) , followed by the next centauri which is approximately 4.22 light years from the earth, and continued by its two companions of that triple system, Alpha centauri and Beta centauri that are approximately 4.37 light-years away from the earth.
In the stars are the various elements of which the universe is composed, hydrogen being the most abundant element in them, followed by helium and other elements, which are constantly subjected to thermonuclear reactions, and it is thanks to these thermonuclear reactions, that the fusion of the atomic nuclei of several elements occurs, causing that they transform into other heavier elements and release great amounts of energy in the process. An example is hydrogen that is transformed into helium and this, in other elements with higher atomic weight and so on. The ways in which they release energy are multiple, such as electromagnetic radiation, neutrinos, stellar wind, and light, (visible and invisible to the human eye). Electromagnetic radiation is a combination of magnetic fields and electric fields, that are oscillating and that propagate through space, transporting energy from one place to another. Neutrinos are fermionic subatomic particles, with neutral electrical charges.
Through millennia the human being has observed the stars, sometimes identifying them with gods, mythological beings or deceased ancestors, naming them individually or in groups (constellations), being so important in some cultures that even the name of the star derives from the name of a deity, the goddess Istar, (Istar = a star), from Sumerian mythology.
Some of the characteristics that the stars possess:
Training.- The stars are formed from the condensation of existing matter in clouds of gas and dust; where atoms thanks to the gravitational force begin to collapse against each other contracting and generating heat, which is increased reaching the generation of thermonuclear reactions, (transforming hydrogen atoms into helium, for example), and the force of gravity as the mass of the star increases, which attracts more material, which when colliding with each other, generates more heat and a greater force of gravity, condensing the matter even more, continuing the cycle, becoming the mass every time denser and turning faster and faster, until the moment in which the matter reaches a hydrostatic equilibrium in which it stops contracting. The energy is radiated outwards in the form of light, photons,
Classification.- Stars are classified by the spectrum of light they emit; after the discovery that the spectra of the stars are arranged in continuous sequences depending on the intensity of certain absorption lines, corresponding to certain elements of which they are composed. Depending on the composition of each star they are designated with certain letters, depending on the elements that predominate in their composition, because when consuming certain elements as fuel over time, (mainly hydrogen and helium), they decrease, thus allowing the identification of the age of the star.
- Class A.- hydrogen predominates in its spectra.
- Class B. – Helium lines reach maximum intensity The intensity of hydrogen lines increases steadily in all subdivisions.
- Class F.- highlight the so-called H and K lines of calcium.
- Class G.- Includes stars with strong H and K lines of calcium and less strong hydrogen lines. Our sun belongs to this group.
- Class O.- Lines of helium, oxygen and nitrogen, in addition to those of hydrogen.
- Class M. – Spectra dominated by bands that indicate the presence of metal oxides, especially those of titanium oxide.
- Class K.- Stars that have strong calcium lines and others that indicate the presence of other metals.
Another way to classify them is by the color they present:
- Yellow color, (like the Sun).
- Color blue.
- White-blue color.
- White color.
- White-yellow color.
- Red color.
As well as the size of its mass.
There are billions.- According to calculations of astronomers, only in the Milky Way are between 200 and 300 billion stars, distributed along the spiral that forms our galaxy, being only a fraction of the stars that exist in the different known galaxies. , which amount to almost incalculable figures, estimating then an approximate number of forty billion of trillions, 40,000,000,000,000,000,000,000, (a four plus twenty-two zeros), basing that estimate on the appraisal of 200 billion galaxies that is believed to exist in our universe , calculation that is made by measuring the approximate mass that exists within a galaxy, and from there an estimate of the mass of other galaxies is calculated, making estimates of the number of stars in these galaxies.
They have their own light.- Unlike other bodies that are in space, such as planets, asteroids, comets, and clouds of gas and dust that do not have their own light, the stars do radiate luminosity, being precisely that luminosity, which is sometimes reflected by the other space bodies. Some stars of great mass and size, reach a point during their life that due to the various thermonuclear reactions inside, they end up consuming their fuel, reaching to expand rapidly, producing a burst of matter, energy and light, that even it can be seen with the naked eye in very distant places, illuminating even with a luminosity superior to that of other stars, which are relatively closer to a planet, as it happened in the year 1006,
They have a very large gravitational force .- Stars have very large masses to possess large amounts of matter, which by gravitational force is compressed; that force of gravity attracts various bodies towards itself, trapping within its mass or in orbits near them, large celestial bodies (planets), as well as asteroids, comets and clouds of gas and dust, sometimes forming solar systems, where the different bodies revolve around the star or the stars that make it up, because these are the celestial bodies with greater mass and gravitational force, there are stars that revolve around other stars of greater size.
They radiate energy.-The different kinds of stars, regardless of their size or color, radiate various types of energy; between the energy that diffuses to the space is the calorific energy, and diverse radiations like the light (like the visible and invisible waves to the human eye) and the diverse radiations that conform the electromagnetic spectrum, infrared rays, visible light (including all the range of wavelengths that can be seen), Ultra Violet rails, X-rays, Gamma rails, and cosmic rays, as well as neutrinos, which are expelled in all directions into space, spreading energy to the ends of the universe. In this respect it is necessary to emphasize that some stars, accumulate such amount of matter that their gravity increases vertiginously attracting more and more matter, arriving at the point in which the star collapses in itself,
With respect to the stars that collapse and turn into black holes, it has been discovered that they spin more rapidly than other stars, engulfing the matter in a spiral or swirl, rotating at extremely fast speeds, and it is believed that this swirling movement could reach speeds close to that of light. And when entering the matter in the black hole and spin at such high speeds, generates the expulsion of matter (gas, and various particles,) as well as energy, expelling it to the ends of the universe with a very large momentum and speed, ejecting jets of matter and energy at almost the speed of light. This hypothesis is a consequence of the observations made by physicists and astronomers in the cluster of galaxies called MS 0735.6 + 7421,
They transform the elements they contain.- Thermonuclear reactions cause the fusion of other elements, transforming them into heavier elements. Hydrogen is transformed into helium, and helium into other heavier elements. In this respect it has been observed that it is in the stars of greater size (mass), that is where the heavier elements are created.
They generate magnetic fields.- The stars have magnetic fields, which rise for several kilometers of their surfaces, creating so-called solar crowns, which collide, releasing ionized particles at very high temperatures, which are fired into space at high speeds. These sets of particles are called solar wind; this solar wind expands through space, sometimes clashing with celestial bodies such as planets and asteroids, is the case of the magnetic field of our star the sun, which generates solar wind that reaches our planet, which could end the life, if not because the planet earth has a magnetic field, which protects it, diverting the different radiations that the solar wind carries. In this respect, a phenomenon that occurs when there are solar explosions is highlighted,