Sunday, July 13, 2008

All About The Stars

by Dave Clark

We all love gazing stars in the sky but do we know as to what are these stars made up of and how they are born. Well, there are lot many questions surrounding the stars. So, let us begin with their formation. Stars are basically made up of plasma. Nebula is a term often used in this regard. It basically refers to the assemblage of dust particles and gas and when all these dust particles and gases get together, they form a star.

Did you know that sun is also a star? It might appear strange to you, but yes sun is also a star which appears to be bigger than rest of the stars but is actually smaller in comparison to others. Not only that, it also has a much less quantity of mass as compared to others. This is the reason why it has been able to survive for so long. After knowing this fact, you must have come to know that mass of the star is inversely related to its life cycle; the more the mass a star has, the lesser will be its life span and vice versa.

Let us now discuss the life cycle of a small star of about one solar mass. It passes through different stages of life. As mentioned before, when nebula is available in high density, it leads to the formation of a star. After that, it condenses to form a huge blob of gas and ultimately contracts under its own gravitational force. As the star becomes hot, it glows in the sky and transforms into a protostar. If it has adequate substance, it attains a very high temperature of 15 million degrees centigrade. At this heat level, nuclear reactions take place, thereby causing fusion of hydrogen. This in turn gives rise to helium. At this stage, the star starts releasing energy and shines all the more. It is now called the main sequence star.

A small star stays into the main sequence stage till the entire hydrogen converts into helium. In the next stage, the helium core begins to shrink. When the core becomes extremely hot, it causes fusion of helium to form carbon. This leads to the expansion of its outer layer. After some time, it becomes cool and glows. The expanded star is popularly called red giant. After a certain period, the helium core vanishes and its outer layer goes away from the star in the form of a gaseous shell. The left core turns into a white dwarf and fades away. Then a stage comes when the star stops glowing and is called a black dwarf. So, this is the life cycle of a star.

About the Author

Dave Clark is a freelance article writer and has been in the industry for many years, he has written many books and is very knowledgeable in various fields, Dave also works for Cushy Sofa a supplier of memory foam mattresses, sofas and Divan sets.

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