The Sun
The Sun is known as the only one star in the Solar system. It is the center, around which the planets, asteroids, satellites, comets, space dust are revolving. The nature of each planet depends on the distance that separates the planet from the Sun. This bright star is important for all the planets surrounding it. So, how much the humanity knows about the fiery star that can kill the entire earth in one second?
Since the beginning of time, people looked at the sky, hoping to learn a little about the twinkling stars and the fiery sun. As we know now, the Sun is the sphere consisting of hot gas, having a diameter of 1.4 million km and locations at a distance of 150 million km from Earth. Without solar energy and heat, the life on Earth would not exist. Huge temperature and pressure in its nucleus cause a thermonuclear reaction with heat emission. Solar radiation determines the climate of our planet.
Scientists agreed that fiery star appeared nearly 4.6 billion years ago. At first, it was just a solar nebula, a huge cloud of gas and dust. Then, because of the gravity, the giant cloud collapsed, and turned into a flat disk. The major part of the space matter formed the Sun.
Being a star, it does not have a hard surface. It consists of the hydrogen and helium. These gases are held by their own gravity. The core of the Sun has temperature about 27 million degrees Fahrenheit. The photosphere, which is the name for the Sun’s surface, has temperature about 5788 K. There are several spots at the surface of the Sun, a bit darker than the rest of the photosphere. These spots are form and move over its surface in accordance with the rotation of the Sun. The temperature at the spots is only 3800 K. They are the result of the complicated convergences with the magnetic field of the star. The amount of the pots depends on the activity of the magnetic field of the Sun. The quantity of them vary from none to 260 spot during the solar cycle, which lasts about 11 years. The magnetic field of the Sun is that strong, that extends up to the Pluto.
The Sun looks like a big dazzling yellow-white ball with the surface, seeming smooth. However, photos of invisible radiation show that the situation on the sun is not so calm. Pulsating granules with dark borders and strange pillars of flame are saying about the powerful storms on the surface of the luminaries.
The inner regions of the sun are in a delicate balance: under the action of gravity, the substance tends to move inside, and the pressure from the hot core and the radiation pushes it back. As it was already mention, temperature at the Sun’s core is so high, that causes the nuclear reactions with the release of gamma radiation. The radiation is so fatal, if it allowed breaking out of the Sun. Fortunately, the diameter of the core is four times smaller than the diameter of the sun, and it is surrounded by layers of material that absorbs the gamma rays and turns them into light.
Apart from the heat and light, the Sun effuses low-density flow of protons and electrons. This stream of particles is called solar wind, which spread throughout the solar system.
The Sun is composed of several layers. The inner layer of the Sub is called the core. The core takes nearly 25% of the whole body of the star. The temperature at the core is the most high and in the core, almost all energy of the Sun is produced.
The next layer is called the radiative zone. It takes about 70% outside the core of the star. At this layer a hot plasma radiates the energy from the core.
There is also the convection zone. This is a place, where the gas is cooled enough and ready to convey the energy that transfers to the surface of the Sun.
The photosphere is the part of the Sun, which one can observe from Earth. Crown, the atmosphere of the star, is the last outer shell of the Sun. The crown consists mainly of prominences and energetic eruptions, outgoing and erupting for several hundreds of thousands and even over a million kilometers into space forming the solar wind.
Because the magnetic activity of the Sun is subject to regular change, and along with this change and its luminosity, it can be considered as a variable star. In the peak years of activity the Sun is brighter than in years of minimum.
As scientist discover, that solar energy will last at least another 5 billion years. After the energy become weak, the Sun will turn to the red giant. Eventually, the red draft will become a white dwarf. As the time will pass, the rest of the Sun will slowly become a cold black dwarf. Nevertheless, this to become a reality, the Sun still has many years to be the main object in the Solar system.
The conclusion is that the Sun is the biggest star in our Solar system and the most important one. For people, animals and plants, the sunlight is very important for the continued existence. The Earth's surface and lower air layers - troposphere, where clouds are formed and there are other meteorological phenomena, directly receive energy from the Sun. Also, important for living organisms is the Sun radiation in the ultraviolet range. Thus, under the action of ultraviolet radiation is formed vital vitamin D. Therefore, as it mention above, the Sun plays an important role in the Solar system.
Works Cited
Choi, C. (2014). Earth’s Sun: Facts About the Sun’s Age, Size and History. [online] http://www.space.com. Available at: http://www.space.com/58-the-sun-formation-facts-and-characteristics.html [Accessed 19 Apr. 2015].
Millis, J. (2010). Basic Information about the Sun. [online] http://space.about.com. Available at: http://space.about.com/od/sunsol/a/The-Sun.htm [Accessed 19 Apr. 2015].
http://science.nationalgeographic.com, (2015). Sun. [online] Available at: http://science.nationalgeographic.com/science/space/solar-system/sun-article/ [Accessed 19 Apr. 2015].
