Electromagnetic waves are of the utmost importance in the area of engineering. Modern and classic engineering commonly choose to make use of electromagnetic waves. Optical Astronomy and Wireless Communication employ electromagnetic waves with equal levels of relevance as well (Shevgaonkar, 2005).
In terms of the hierarchy of the universe, stars are considered to be present between amalgamations of such small nature that they are unable to ignite and amalgamations that are far too unbalanced to persevere (Day, 1999). Modern day technology has allowed man to discover that what appeared to be stationary and permanent entities in the sky are in reality going through a highly intricate and complex cycle. They do not simply continue to shine as they appear to be doing so but go through a complete cycle of life, spanning from their life to their deaths.
When a star first takes birth, it is referred to as a nebula (Marks, 2005). At this point, the star is nothing more than a cloud of gases and dust particles. More specifically, the major constituent of these gases is hydrogen while helium takes on a smaller share of the star. Eventually, the formation of gravity within the nebula causes the gases and dust particles to come together and accumulate their atomic masses in a manner such that the gravitational pull of the nebula increases, hence causing the attraction of more dust particles and gas towards the nebula. This results in the addition of atoms to the structure of the nebula which leads to the execution of numerous reactions within the mass of the nebula. What forms as a result of these reactions and gravitational attraction is referred to as a prostar and is highly unstable (Leslie & Caldwell, 2001). It is perhaps the first recognizable form that the star takes during the course of its life time.
However, it is essential to highlight that unless the prostar acquires equilibrium soon after its generation it will not be able to enter the next phase of its evolution and will eventually die. In order to become stable, it is imperative that the prostar takes on a form such that its constituents are in equilibrium. In precise terms, the gravitational pull present at the center of the star has to be in balance with the pressure of the numerous gases that are attempting to push the prostars heat and light away from the body of the prostar.
It is essential to highlight that the pressure of the gas opposes the collapsing of the nebula while the density of the prostar’s core continues to increase as atoms continue to collide and attempt to share the same space inside the prostar. In the case that the star collapses and does not manage to reach the next stage of its evolution, it collapses into what is generally referred to as a brown-dwarf. If the prostar succeeds in acquiring equilibrium between its gases, dust particles and gravitational pull, the core of the star reaches a temperature so high that an internal fusion process begins on the basis of the excessive hydrogen at the core of the star as it reacts with other gases. At this point, the prostar can be referred to as a star.
The rest of the star’s life is spent in the burning away of the star’s hydrogen gases in a continuous fusion process within the core of the star. This burning away of the hydrogen gases in a fusion process is commonly referred to as the main sequence of the star and it is during the course of the main sequence that the star shines as we observe it across space. The main sequence can continue for countless years that can span well into and over a billion. It is imperative to note at this point that as the main sequence continues, the star continues to lose heat and energy. In order to compensate for the lost heat and energy, the star steadily contracts in size.
Once all the hydrogen within the star has burnt away, the star eventually evolves in a manner such that the helium gases in the star fuse with the carbon to form heavier elements. In a universal perspective, the star takes on a form that is extremely heavy in terms of mass and can perhaps be considered to be some of the heaviest elements that the universe makes.
A highly significant attribute of stars that merits highlighting at this point is the fact that the larger the size of the star is, the more rapidly it burns away during the fusion process in light of the fact that it requires the burning away of more fuel in order to compensate for its larger mass. On the other hand, a smaller star does not need to burn away hydrogen as rapidly and can therefore be expected to last longer than larger stars.
Once all the hydrogen in the star has burnt out and the fusion process drops to give way to a temperature drop in the star, the core begins to contract all the more rapidly which results in an increased number of collisions within the star causing the density of the core to spike once more. This eventually leads to the re-engaging of the fusion process and the fusion cycle begins once more. However, it is imperative to note that this time, the fusion process is credited to the helium presence in the star and it is because of the same reason that this repetition of the cycle is far more unstable than its predecessor.
At this point the star is referred to as a Red Giant in light of the fact that the size of the star increases in an attempt to keep heat and light from escaping. Once helium has run out as well, the star enters its final stage which is commonly referred to as carbon burning. However, once the carbon burning comes to a close as well, the star eventually collapses to form what is referred to as a white dwarf.
Stars are highly significant elements where the study of the origins of the universe is concerned. The manner in which they evolve as well as the nature of reactions that takes place inside them along with the time span that they take in going through their life cycles can be used and are being studied by man to acquire an understanding of the Milky Way, the galaxy and the origins of the universe (Zuckerman & Malkan, 1996). In light of the above discussion, we can surmise that stars are highly complex and hold a significant position with respect to the role that they play in the universe.
References
- Day, W. (1999). The Structure of the Universe.
- Leslie, L. & Caldwell, J. S. (2001). Qualitative Reading Inventory. Bel Air: Longman.
- Marks, M. (2005). Science. Huntington Beach: Creative Teaching Press.
- Shevgaonkar, R. K. (2005). Electromagnetic Waves. Powai: Tata McGraw-Hill.
- Zuckerman, B. & Malkan, M. A. (1996). The Origin and Evolution of the Universe. Sudbury: Jones & Bartlett Publishers.