Astronomy Essay Example | Topics and Well Written Essays - 750 words

Astronomy - Essay Example 4). Explain how type I and Type II. Supernovae occur. 1). The four main grouping of stars as depicted by the Hertzprung- Russel diagram are dwarf (white and red) stars, main sequence grouping stars, giant stars and supergiant stars (p. 142). The white dwarf stars are Sirius B, Wolf 486, Van Maanen's star, Procyon B, Wolf 1346 and 40 Eridani B. The size characteristic of these stars is ranging from 0.008 R to 0.03 R. The stars in the white dwarf category have temperatures ranging from 5,000 K to 25, 000 K. In between the white dwarf stars and the main sequence grouping we have Bernard's star. Bernard's star is a red dwarf. It has a radius of about 0.1 R and 150 L/L. Bernard's star is also the coolest star with temperatures of 2900 K. The white and red dwarf stars have Mv > 15. The main sequence stars are Aldebaran B, Alpha Centauri B, the Sun, Altair, Sirius, Procyon A, Vega, Rigel B, Pollux, Spica B, Spica A, Adara and Capella B. The luminosity class of these stars is V. The size of these stars vary from 1R to 10R. The stars in the main sequence grouping vary from 7,000 L/L to 85,000 L/L. The main sequence grouping stars have temperatures ranging from 3700 K for Aldebaran B to 30,000 K for Adara. The main sequence stars have between 5- 10 Mv. The next sequence of stars are the giants. Included in the giant classification of stars are Capella A, Aldebaran A, Arcturus, Mira and Canopus. The giant classification of stars have radii which vary from 10 R to 100 R. The luminosity class of the giant stars are III. The giant stars have a Mv between 0- 5. The next sequence is the supergiant sequence of stars. This includes Polaris, Deneb, Rigel A and Alnilam. The supergiants temperatures range from 10,000 K to 30,000K. The luminosity class is Ib. The largest stars are Betegeuse and Antares,.Betelgeuse has a size of 1000 R. Antares has a size of about 2000 R. The Mv for these stars is – 5 (p. 143). 2). A star is born from the thin gases of space. When a star is bo rn, there is normally a large cloud of gas and dust. The thin gases of space are known as the interstellar medium ( p. 162). When enough hydrogen is compressed through the gravity of these stars, hydrogen fusion is achieved. In the center core of these stars there is a helium core. A teaspoon of mass of helium from the center of a star would weigh more than a ton. When enough helium is compressed in the center of the star, there is an abrupt explosion of intense magnitude called a helium flash. For this particular moment in time, the center of the newly born star produces more energy per second than an entire grouping of stars. This helium flash causes the center of the star to increase in temperature, whereas a great number of electrons become excited by the reaction. This causes the hydrogen to fuse into helium. At that point, the star is born with a self sustaining hydrogen fusion reaction at its shell. Often there is a helium fusion reaction at the center of the star. The size o f the star is of the utmost importance, stars less than 0.40 solar masses never get enough energy to continue the helium fusion reaction process. Stars which are greater than 3 solar masses experience degeneration at their core before this phenomenon occurs (p. 187). In the star there are two types of fusion reactions, helium fusion at the center and hydrogen fusion at the shell. 3). A star begins to die when the helium fusion which occurs at its center begins to produce carbon, oxygen and neon. As the fusion

Timothy McVeigh Research Paper Example | Topics and Well Written Essays - 1750 words

Timothy McVeigh - Research Paper Example Unarguably, the case of Timothy McVeigh is one of the most infamous and heinous crimes ever committed in the United States. It is second only to the damage wrought by the 9/11 terrorist attacks in New York in damage to property lives claimed. What made it particularly significant, however, is the fact that McVeigh is an American citizen, which made his terrorist act homegrown as opposed to the 9/11 terrorist attacks, which was perpetrated by foreign terrorists. This paper will explore the criminal theories behind his act as well as in the dynamics of the drama that unfolded in the course of his arrest and trial, which culminated in his execution. This is particularly because there was so little effort to comprehend his act and his motivations because there was a collective clamor for his death and nothing else just so he could no longer repeat his feat. The sentiment was understandable, as McVeigh – throughout the whole affair stood unmoved and unrepentant, coldly defending hi s action as rational and calling the victims â€Å"collateral damage† in his twisted notion of things. ... The tragic event, wrote Stein, effectively â€Å"shattered the mythic invulnerability of the American â€Å"Heartland†Ã¢â‚¬ . (p. 51) McVeigh was apprehended a little over an hour later on a different charge – that of transporting a firearm. â€Å"By August 1995, McVeigh and co-defendant Terry Nichols had been charged with conspiracy, use of weapon of mass destruction, destruction by explosives, and eight counts of first-degree murder.† (Greene and Heilburn 2010, p. 189) When McVeigh was apprehended, along with his cohort, Terry Nichols, America was again shocked to find that these clean-cut men, both served in the country’s armed forces, were responsible for planning and implementing an action that would kill hundreds of their countrymen. In the process, they methodically constructed and detonated bombs, with the plan as some sort of revenge and catalyst to his separatist movement. (Disilvestre 2003, p. 64) For this paraphrase, this is the information/d irect quote from the source (I will include the quotes if you want to use it): â€Å"Timothy McVeigh, just 29 years, was the ex-soldier convicted of constructing, planting and detonating the bomb that killed so many of his countrymen. Terry Nichols, 42, was convicted of helping McVeigh plan, purchase and steal materials in order to construct the bomb.† (Disilvestre, p. 64) Criminological Theories Again, it must be emphasized that contemporary interest on the motivational factors for McVeigh’s crime was close to nonexistent as many Americans wanted closure and the sense of security that came with finally putting the man who murdered hundreds of Americans to death. If the public and criminologists themselves bothered to look, there are existing criminological theories that could explain McVeigh’s behavior and