The Life Cycle of a Star

Introduction For millenniums, stars have fascinated the human race. In medieval times, these heavenly bodies were thought to possess mystical powers and some civilizations even worshiped them. This supernatural view was caused by the lack of information on the true nature of stars. Modern science has enabled man to study stars and come up with scientific explanations of what they are and why they shine. Astronomers in the 20th century have been able to come up with a credible model of the entire life cycle of stars.Advertising We will write a custom essay sample on The Life Cycle of a Star specifically for you for only $16.05 $11/page Learn More Green and Burnell (2004) state that the life cycle of a star takes place over a timescale that appears infinitely long to human beings. Astronomers are therefore unable to study the complete life cycle of stars since the changes occur at a very slow rate to be observed. The evolutionary pattern of stars is theref ore deduced by observing their wide range at different stages of their existence. This paper will set out to provide a detailed description of the life-cycle of a star. Birth of a Star Stars are born from vast clouds of hydrogen gas and interstellar dust. This gas and dust clouds floating around in space are referred to as a nebula (NASA2010). Nebulas exist in different forms with some glowing brightly due to energizing of the gas by previously formed stars while others are dark due to the high density of hydrogen in the gas cloud. A star is formed when the gas and dust making up the nebula start to contract due to their own gravitational pull. As this matter condenses due to gravitational pull, the gas and dust begin to spin. This spinning motion causes the matter to generate heat and it forms a dull red protostar (Krumenaker, 2005). When the protostar is formed, the remaining matter of the star is still spread over a significant amount of space. The protostar keeps heating up due to the gravitational pressure until the temperature is high enough to initiate the nuclear fusion process (NASA, 2010). The minimum temperature required is about 15 million degrees Kelvin and it is achieved in the core of the protostar. The nuclear fusion process uses hydrogen as fuel to sustain the reaction and helium gas is formed from the fusion of the hydrogen nuclei. At this stage, the inward pull of gravity in the star is balanced by the outward pressure created by the heat of the nuclear fusion reaction taking place in the core of the star (Lang, 2013). Due to this balance, the star is stable and because of the nuclear fusion, considerable heat and a yellow light is emitted from the star, which is capable of shining for millions or even billions of years depending on its size. Mature and Ageing Stars The newly formed star is able to produce energy through nuclear fusion of hydrogen into helium for millions to billions of years. During the nuclear fusion process, the heavier h elium gas sinks into the core of the star. More heat is generated from this action and eventually, the hydrogen gas at the outer shell also begins to fuse (Krumenaker, 2005).Advertising Looking for essay on astronomy? Let's see if we can help you! Get your first paper with 15% OFF Learn More This fusing causes the star to swell and its brightness increases significantly. The closest star to the Earth is the Sun and scientists predict that it is at this stage of its life cycle. The brightness of a star is directly related to its mass since the greater the mass, the greater the amount of hydrogen available for use in the process of nuclear fusion. Death of a Star A star dies when its fuel (hydrogen) is used up and the nuclear fusion process can no longer occur. Without the nuclear reaction, the star lacks the outward force necessary to prevent the mass of the gas and dust from crashing down upon it and consequently, it starts to collapse upon itself (Lang, 2013). As the star ages, it continues to expand and the hydrogen gas available for fuel is used up. The star collapses under its own weight and all the matter in the core is compressed causing it to be being heated up again. At this stage, the hydrogen in the core of the star is used up and the star burns up more complex elements including carbon, nitrogen, and oxygen as fuels. The surface therefore cools down and a red giant star, which is 100 times larger than the original yellow star, is formed. From this stage, the path followed in the cycle is determined by the individual mass of a star. Path for Low Mass Stars For low mass stars, which are about the same size as the Sun, a helium fusion process begins where the helium making up the core of the star fuses into carbon. At this stage, a different heating process from the original hydrogen nuclear fusion process occurs. Al-Khalili (2012) explains that due to the compression heat, the helium atoms are forced together to make heavier elements. Wh en this occurs, the star begins to shrink and during this process, materials are ejected to form a bright planetary nebula that drifts away. The remaining core turns into a small white dwarf star, which has an extremely high temperature. The white dwarf is capable of burning for a few billion years but eventually it cools. When this happens, a black crystalline object referred to as a black dwarf is formed. Path for High Mass Stars For high-mass stars which are significantly bigger than the Sun, the carbon produced from helium fission fuses with oxygen. More complex reactions occur and eventually an iron core is formed at the center of the star. Since this iron does not fuel the nuclear fission process, the outward pressure provided by the previous nuclear process does not occur and the star collapses. The collapse leads to a supernova explosion. Green and Burnell (2004) describe a Supernova as the â€Å"explosive death of a star† (p.164). During this explosion, the star prod uces an extreme amount of energy, some of which is carried away by a rapidly expanding shell of gas. The exploding star attains a brightness of 100 million suns although this amount of energy release can only last for a short duration of time.Advertising We will write a custom essay sample on The Life Cycle of a Star specifically for you for only $16.05 $11/page Learn More For stars that are about five to ten times heavier than the sun, the supernova is followed by a collapse of the remaining core to form a neutron star or pulsar. As the name suggests, neutron stars are made up of neutrons produced from the action of the supernova on the protons and electrons previously available in the star (Krumenaker, 2005). These stars have a very high density and a small surface area since their diameter stretches for only 20km (Al-Khalili, 2012). If the neutron star exhibits rapid spinning motion, it is referred to as a pulsar. For stars that are 30 to 50 times he avier than the Sun, the explosion and supernova formation lead to the formation of a black hole. In this case, the core of the star has a very high gravitational pull that prevents protons and neutrons from combining. Due to their immense gravitational pull, black holes swallow up objects surrounding them including stars and they lead to a distortion of the space. Parker (2009) observes that the gravity of the black hole is so strong that even light is unable to escape from this pull. The only substance thing that black holes emit is radiation mostly in the form of X-rays. Conclusion This paper set out to provide an informative description of the life cycle of a star. It started with nothing but modern astronomy has made it possible for mankind to come up with a convincing sequence for the life cycle of a star. The paper has noted that all stars are formed from a nebula cloud. It has revealed that the life expectancy of stars can vary from a million to many billions of years dependi ng on their mass. A star begins to die when it runs out of hydrogen and the fusion reaction can no longer occur. The paper has also demonstrated that the death of a star is dependent on its mass. If a star is the size of the Sun, it will die off as a white dwarf while if it is significantly bigger, it will have an explosive death as a supernova. References Al-Khalili, J. (2012). Black Holes, Wormholes, and Time Machines. Boston: CRC Press.Advertising Looking for essay on astronomy? Let's see if we can help you! Get your first paper with 15% OFF Learn More Green, S.F., Burnell, J. (2004). An Introduction to the Sun and Stars. Cambridge: Cambridge University Press. Krumenaker, L. (2005). The Characteristics and the Life Cycle of Stars: An Anthology of Current Thought. NY: The Rosen Publishing Group. Lang, R.K. (2013). The Life and Death of Stars. Cambridge: Cambridge University Press. NASA. (2010). The Life Cycles of Stars: How Supernovae Are Formed. Web. Parker, K. (2009). Black Holes. London: Marshall Cavendish. This essay on The Life Cycle of a Star was written and submitted by user Edith Martin to help you with your own studies. You are free to use it for research and reference purposes in order to write your own paper; however, you must cite it accordingly. You can donate your paper here.

mythology Research Paper Example

mythology Research Paper Example mythology Paper mythology Paper The role of women in ancient Greek life was insignificant compared to that of Greek men. A womans Job was to take care of the children and to cook and clean unless she had servants or slaves that would do it for her. Yet, in Greek mythology, women were often written as major characters. Well-known Greek plays contain many well- written, complex, female characters. Female individuals in Greek mythology were often seen as very powerful and fierce Greek mythology is the body of myths and teachings that belong to the ancient Greeks, concerning their gods and heroes, the ature of the world, and the origins and significance of their own cult and ritual practices. It was a part of the religion in ancient Greece. Modern scholars refer to and study the myths in an attempt to throw light on the religious and political institutions of Ancient Greece and its civilization, and to gain understanding of the nature of myth-making itself. l] Greek mythology is explicitly embodied in a large collection of narratives, and implicitly in Greek representational arts, such as vase-paintings and votive gifts. Greek myth attempts to explain the origins of the world, and details the lives and dventures of a wide variety of gods, goddesses, heroes, heroines, and mythological creatures. These accounts initially were disseminated in an oral-poetic tradition; today the Gre ek myths are known primarily from Greek literature. The oldest known Greek literary sources, Homers epic poems Iliad and Odyssey, focus on the Trojan War and its aftermath. Two poems by Homers near contemporary Hesiod, the Theogony and the Works and Days, contain accounts of the genesis of the world, the succession of divine rulers, the succession of human ages, the origin of human woes, and the origin of sacrificial practices. Myths are also preserved in the Homeric Hymns, in fragments of epic poems of the Epic Cycle, in lyric poems, in the works of the tragedians of the fifth century BC, in writings of scholars and poets of the Hellenistic Age, and in texts from the time of the Roman Empire by writers such as Plutarch and Pausanias. Archaeological findings provide a principal source of detail about Greek mythology, with gods and heroes featured prominently in the decoration of many artifacts. Geometric designs on pottery of the eighth century BC depict scenes from the Trojan ycle as well as the adventures of Heracles. In the succeeding Archaic, Classical, and Hellenistic periods, Homeric and various other mythological scenes appear, supplementing the existing literary evidence. [2] Greek mythology has had an extensive influence on the culture, arts, and literature of Western civilization and remains part of Western heritage and language. Poets and artists from ancient times to the present have derived inspiration from Greek mythology and have discovered contemporary significance and relevance in the themes. [3] mythology By monicalhouston

Personal Leadership Development Project Paper Essay

Personal Leadership Development Project Paper - Essay Example The training period, all the trainees are conduct seminar, study classes etc, for developing the quality of employees. It is a good training. Verizon wireless, my role is to design the job, job analysis, human resource planning, recruitment, selection, hiring, induction, evaluation of performance, compensation management, training and development, welfare administration, employee movements, health and safety administration, grievance handling, discipline etc. The H R training in offices getting lot of experience, these experience are helps to manage the colloquies in the organization, also helps to identify the minds and behaviour of sub-ordinates. In my carrier planned some strategies. First one is to keeping 99% attitude for work and personal matter. Attitude is 99 percent, every person’s carrier is successful, for the reason I am keeping attitude for one year for the marketing training period, and our attitude is loose at one time for losing our carrier. Another strategy is to don’t cheating others. As a manager, in my view, to achieving the goal of the organization, to motivate and trained to the subordinates to achieve the higher volume of business. Which subordinates are performing better, to give additional bonus, gifts etc,. The main role of HR manager is to functioning the effective utilization of human resource in an organization. The overall goal of the organization is to building strong brands, expanding the bus iness, and getting marketing leadership. The main goal of organization is to create a new business in new areas. The top of the organization focusing expanding the networks across the countries. The training is conducting in the branch office; communicate the sub-ordinates for the entire process of organization and the organizational goals. The aim and objectives of the company is to achieve the market leader in wireless network. It is a very good feedback from my sub-ordinates or trainees, because,

Building and leading creative teams Research Paper

Building and leading creative teams - Research Paper Example Mayo’s motivation theory can therefore be applied in understanding another possible reason why Jeannie ceased to work as a freelancer and joined McTate & Mann advertising company. It is possible that Jeannie considered the social needs of being viewed as a career driven individual by the society by going to work rather than freelancing from home. Nonetheless, the main focus of Mayo’s motivational theory is the manner in which managers and leaders treat employees in relation to meting their social needs (Wilson & Madsen, 2008). It is evident that the social needs of both Jeannie and Sandy are met at the work place because they are happy with their work. The social needs of employees are further described by Maslow’s theory of motivation. According to Maslow’s theory, there are five distinct levels of human needs which should be met for them to feel motivated. The social needs of employees are postulated by Maslow within the third level of his hierarchy of needs. These include the sense of belonging and love needs (Wilson & Madsen, 2008). It can be depicted therefore that Sandy and Jeannie were motivated to leave their respective jobs for McTate & Mann because they needed to belong to a group. Moreover, Sandy and Jeannie needed to belong to a recognized company which met their needs for belonging. In addition to the social needs, the physiological needs are postulated in the first level of Maslow’s hierarchy of needs. The physiological needs include hunger and thirst (Wilson & Madsen, 2008). Through a good pay at McTate & Mann, Sandy and Jeannie would not go hungry or thirst. Therefore this justifies their motiv ation to work with the advertising company rather than their previous jobs. Furthermore, Maslow’s theory of motivation postulates that employees are motivated if their safety needs are met (Viorel, Aurel, Virgil & Stefania,

The Asda Effect Assignment Example | Topics and Well Written Essays - 1000 words

The Asda Effect - Assignment Example Everything changed all of a sudden as Asda found itself with demoralized employees, slow growth in sales, and declining profits in 1991. It had been a 1 billion pounds cash surplus supermarket chain in 1987, and by 1991 it had a debt of over 1 billion pounds. That was precisely the state of affairs at Asda when Archie Norman entered into the scene as Chief Executive Officer (CEO).The main reasons of the problems that Asda and Archie Norman had to face were due to complex organizational inefficiencies that they had to solve as soon as possible, right away, in order to survive, and at the same time, Asda had to become an efficient organization once again.  Ã‚   Among the different reasons behind Asda’s failures by mid-1991 were the following:   Asda as an organization with its own culture had become a bureaucratic and hierarchical institution beginning in the 1980s.   As a direct result of this rigid functioning structure in the company, any kind of innovation was stopped from being encouraged or implemented.   Without any innovation, Asda was unable to keep its competitive advantages in the retail market in the United Kingdom.   (Weber and Beer, 1998a:   p. 6).   So Asda and Archie Norman had to face the challenge of transforming the superstore in relation to its management style of doing things as well as implementing a sense of culture based on the core values of Asda.   Management and leadership had to change significantly in order to create a new productive and efficient organization.     Ã‚  Ã‚  Ã‚  

The Importance of Narrative Analysis in a Fake News World

The Importance of Narrative Analysis in a Fake News World Heroes, Villains, and Strangers: The Importance of Narrative Analysis in a Fake News World In When Narrative Matters More Than Fact, Ashley Lamb-Sinclair argues that Facts [ ] mean very little to people caught up in storylines. When it comes to creating ideologies and perceptions about the world, narrative is more powerful than facts and figures. Human beings tend to believe ideas that arise out of internal narratives, and these narratives are often based on limited personal experience. In an era of fake news, there is a tendency for teachers to focus on fact-checking as a way for students to combat erroneous information. Lamb-Sinclair argues that fact-checking is not the most effective approach to addressing errors in perception. Rather than placing an emphasis on facts and figures, adults should teach young people to analyze narratives and identify unreliable narrators, as well as heroes and villains. Lamb-Sinclair argues that narratives shape beliefs, and minds are changed when narratives change. The author draws upon her own experiences and provides two examples of the way that narrative has affected her own views. In high school, a love of historical narrative affected the author so deeply that she chose to study history in college. Perhaps even more significantly, Sinclairs youth experience working with two Latino men who were a little more flirty than is probably appropriate to be toward a 17-year-old girl became the source of her own temporary prejudice against older Latino males. It wasnt until she moved to Southern California and became sisters with Latina women in a sorority that she was able to form a new image of Latino men. While in the sorority, she went on dates with several men, and had the best carne asada from the father of her Latino friend. These new experiences caused her internal narrative about Latino men to shift, and her perceptions changed along with the n arrative. The author also points out that in an era of fake news, an emphasis on fact-checking and trying to persuade people through facts is largely unsuccessful. Narrative is rooted in the human experience, and will always be more compelling than a collection of facts. Even when people are not conscious of being involved in narrative, they want to connect with characters and to follow a plot to its end through multiple layers of conflict. The fascination with story and narrative structure means that emphasizing the extent to which a statement is factual has little impact on someone, if that person has already formed a narrative that contradicts the facts. Lamb-Sinclair offers an alternative to fact-checking: The best way to teach true understanding is not by teaching students facts (although that is still a valuable lesson); it is to teach them to analyze, as one does with elements of narrative. The recent U.S. general election provides an example of how this alternative approach might be ef fective. Simply pointing out that Donald Trump didnt help save 2,100 jobs with the Carrier deal may not be persuasive for someone who has lost a job and gotten it back. Creating a new narrative that challenges someones pre-existing narrative is far more likely to have an impact on causing someone to question her or his pre-existing views. Lamb-Sinclair sees adults, and particularly teachers, as playing an important role in teaching younger people how to analyze narratives. Teachers must not only teach students how to be critical thinkers who question the validity of facts, but also how to dissect a narrative and to identify unreliable narrators. Teachers must expose students to various types of characters and plotlines from many perspectives, both fictional and real in order for students to develop the analytical skills necessary to engage with real-world narratives. The author suggests that if students are familiar with heroes and villains from literature and history, they will be equipped to recognize heroes and villains in real life situations. Sinclair illustrates her own commitment to narrative by omitting facts and figures from her article and relying on personal narratives to illustrate her points. The efficacy of this approach poignantly demonstrates how susceptible readers are to being swept up in a narrative that makes use of only personal stories and recent events. Sinclair never refers to any statistics or facts when describing the way that her perceptions of Latino men shifted over time, yet her story resonates with the reader and felt trustworthy and factual. The author states that while no one had presented [her] with the facts, she understood much more of the story. Sinclair is critically aware that she has simply rewritten the original narrative, implying that the story is ever changing and another set of experiences could quickly alter what she believes. Lamb-Sinclair recognizes that not everyone has the opportunity to shift internal narratives through exposure to diverse people groups or experiences. The author states that while she was lucky enough to à ¢Ã¢â€š ¬Ã‚ ¦ experience other cultures, the general population is not so fortunate. For that reason, Lamb-Sinclair writes to encourage the education system to teach students analytical skills to avoid another generation where the facts mean very little. If teachers and other responsible adults fail to teach young people how to recognize unreliable narratives and real-world heroes or villains, prejudice and bigotry may take root in our society and permeate the ideologies of future generations.

Spiritual Shallowness in The Great Gatsby :: Great Gatsby Essays

Spiritual Shallowness in The Great Gatsby The American Dream was based on the assumption that each person, no matter what his origins, could succeed in life on the sole basis of his or her own skill and effort. The dream was embodied in the ideal of the self-made man. The Great Gatsby is a novel about what happened to the American dream in the 1920s, a period when the old values that gave substance to the dream had been corrupted by the vulgar pursuit of wealth. Spiritual shallowness is portrayed in The Great Gatsby through the characters' pursuit of power and pleasure, the character groupings and images and the forgotten past. The characters of The Great Gatsby are Midwesterners who have come east in pursuit of this new dream of money, fame, success, glamour, and excitement. Tom and Daisy must have a huge house, a stable of polo ponies, and friends in Europe. Gatsby must have his enormous mansion before he can feel confident enough to try to win Daisy. The energy that might have gone into the pursuit of noble goals has been channeled into the pursuit of power and pleasure, and a very showy, but fundamentally empty form of success. Fitzgerald employs clearly defined character groupings and various images and symbols in developing the theme. Character groups include Nick, the observer and commentator, who sees what has gone wrong, Gatsby, who lives the dream purely, and Tom, Daisy, and Jordan, the "foul dust" who are the prime examples of the corruption of the dream. The primary images and symbols used are, the green light, the eyes of Dr. T. J. Eckleburg, the image of the East and Midwest, Owl Eyes, Dan Cody's yacht; and religious terms such as grail and incarnation. Both the character groupings and the images and symbols suggest a second major theme that may be referred to as "sight and insight." The novel contains many images of blindness, perhaps because hardly anyone seems to "see" what is really going on. The characters have little self-knowledge and even less knowledge of each other. Especially Gatsby- he lacks the insight to understand what is happening. He never truly sees either Daisy or himself, so blinded is he by his dream. The only characters who see, in the sense of "understand," are Nick and Owl Eyes. Spiritual Shallowness in The Great Gatsby :: Great Gatsby Essays Spiritual Shallowness in The Great Gatsby The American Dream was based on the assumption that each person, no matter what his origins, could succeed in life on the sole basis of his or her own skill and effort. The dream was embodied in the ideal of the self-made man. The Great Gatsby is a novel about what happened to the American dream in the 1920s, a period when the old values that gave substance to the dream had been corrupted by the vulgar pursuit of wealth. Spiritual shallowness is portrayed in The Great Gatsby through the characters' pursuit of power and pleasure, the character groupings and images and the forgotten past. The characters of The Great Gatsby are Midwesterners who have come east in pursuit of this new dream of money, fame, success, glamour, and excitement. Tom and Daisy must have a huge house, a stable of polo ponies, and friends in Europe. Gatsby must have his enormous mansion before he can feel confident enough to try to win Daisy. The energy that might have gone into the pursuit of noble goals has been channeled into the pursuit of power and pleasure, and a very showy, but fundamentally empty form of success. Fitzgerald employs clearly defined character groupings and various images and symbols in developing the theme. Character groups include Nick, the observer and commentator, who sees what has gone wrong, Gatsby, who lives the dream purely, and Tom, Daisy, and Jordan, the "foul dust" who are the prime examples of the corruption of the dream. The primary images and symbols used are, the green light, the eyes of Dr. T. J. Eckleburg, the image of the East and Midwest, Owl Eyes, Dan Cody's yacht; and religious terms such as grail and incarnation. Both the character groupings and the images and symbols suggest a second major theme that may be referred to as "sight and insight." The novel contains many images of blindness, perhaps because hardly anyone seems to "see" what is really going on. The characters have little self-knowledge and even less knowledge of each other. Especially Gatsby- he lacks the insight to understand what is happening. He never truly sees either Daisy or himself, so blinded is he by his dream. The only characters who see, in the sense of "understand," are Nick and Owl Eyes.