Star, is a heavenly body that generates its own light and other forms of radiation. The mass of a star—that is, the amount of material it contains—can be determined most accurately if the star is a member of a true double, or binary, system at a known distance from the earth and separated from its companion by a measurable distance. The masses of both stars are calculated by measuring their motions over a period of years and applying the mathematical law of gravitation. Once a star’s diameter and mass are known, its density can be determined.
Stars have a relatively small range of masses but a wide range of diameters. Depending on its original mass, the lifetime of a star ranges from several million years to 20 billion years or more. The rate at which hydrogen in a star undergoes nuclear fusion is proportional to the temperature of the star’s core. The most massive stars have the shortest lifetimes, because the more massive a star is, the greater is the temperature of its core. As a star exhausts its store of hydrogen, it usually becomes a giant or super giant; the star’s outer layers expand and cool as the core contracts and becomes hotter.
The core becomes so hot that helium and heavier elements begin to undergo nuclear fusion. At this stage many stars fluctuate periodically in brightness and are called variable stars. A star of small or average mass eventually loses its outer layers, leaving a dense, very hot body about the size of the earth. The body is called a white dwarf. With massive stars, the core usually collapses, producing a tremendous explosion that ejects suddenly all of the matter from the star’s outer layers. The star briefly becomes very bright and is known as a supernova. The body that remains is
much denser than a white dwarf and forms either a neutron star or in the case of most massive stars, a black hole. Sun, is the star at the center of the solar system. The Probable age of the Sun is about 5,000,000,000 and its predicted death is also 5 billion years from our time now. The sun will undergo the stages of death of an ordinary star. Many people say that we should be afraid when the Sun will die for it will bring great damage to the earth. After a billion or thousand years from now, the great Star’ components will intermix, making the Sun to a Giant Red Star and spread out 200 hundred times.
In this connection, the Sun’s gravitational force towards the Earth will untighten or reduce in tension, thus, making the Earth move or travel to another place. This will affect the Earth’s speed and orbit, which in return affects the whole world. There would be a possibility that the Earth will collide with another planet. But researchers are still trying to figure out ways in which the Earth could possibly be saved after the death of the Sun.
References:
1. “Star”. New Standard Encyclopedia. Volume 16. Pages 768- 778. 2. “Sun”. New Standard Encyclopedia. Volume 16. Pages 891- 896. 3. Lampton, Christopher. The Sun. Watts, 1982.