Radiation in Space and Astronomy - Definition

Astronomy is the study of objects in the universe that radiate (or reflect) energy from across the electromagnetic spectrum. Astronomers study radiation from all objects in the universe. Lets take an in-depth look at the forms of radiation out there. Artwork of a planet orbiting a pulsar. Pulsars are very rapidly spinning neutron stars are the dead cores of massive stars and rotating on their axes often hundreds of times every second. They radiate radio waves and in optical light. Mark Garlick/Science Photo Library (Getty Images) Importance to Astronomy In order to completely understand the universe, scientists must look at it across the entire electromagnetic spectrum. This includes the high-energy particles such as cosmic rays. Some objects and processes are actually completely invisible in certain wavelengths (even optical), which is why astronomers look at them in many wavelengths. Something invisible at one wavelength or frequency may be very bright in another, and that tells scientists something very important about it. Types of Radiation Radiation describes elementary particles, nuclei, and electromagnetic waves as they propagate through space. Scientists typically reference radiation in two ways:  ionizing and non-ionizing. Ionizing Radiation Ionization is the process by which electrons are removed from an atom. This happens all the time in nature, and it merely requires the atom to collide with a photon or a particle with enough energy to excite the election(s). When this happens, the atom can no longer maintain its bond to the particle. Certain forms of radiation carry enough energy to ionize various atoms or molecules. They can cause significant harm to biological entities by causing cancer or other significant health problems. The extent of the radiation damage is a matter of how much radiation was absorbed by the organism. The electromagnetic spectrum show as a function of frequence/wavelength and temperature. Chandra X-Ray Observatory The minimum threshold energy needed for radiation to be considered ionizing is about 10 electron volts (10 eV). There are several forms of radiation that naturally exist above this threshold: Gamma-rays: Gamma rays (usually designated by the Greek letter ÃŽ ³) are a form of electromagnetic radiation. They represent the highest energy forms of light in the universe. Gamma rays occur from a variety of processes, ranging from activity inside nuclear reactors to stellar explosions called  supernovae and highly energetic events known as gamma-ray bursters. Since gamma rays are electromagnetic radiation, they do not readily interact with atoms unless a head-on collision occurs. In this case the gamma ray will decay into an electron-positron pair. However, should a gamma ray be absorbed by a biological entity (e.g. a person), then significant harm can be done as it takes a considerable amount of energy to stop such radiation. In this sense, gamma rays are perhaps the most dangerous form of radiation to humans. Luckily, while they can penetrate several miles into our atmosphere before they interact with an atom, our atmosphere is thick enough that most gamma rays are absorbed b efore they reach the ground. However, astronauts in space lack protection from them, and are limited to the amount of time that they can spend outside a spacecraft or space station. While very high doses of gamma radiation can be fatal, the most likely outcome to repeated exposures to above-average doses of gamma-rays (like those experienced by astronauts, for instance) is an increased risk of cancer. This is something that life sciences experts in the worlds space agencies study closely. X-rays: x-rays are, like gamma rays, a form of electromagnetic waves (light). They are usually broken up into two classes: soft x-rays (those with the longer wavelengths) and hard x-rays (those with the shorter wavelengths). The shorter the wavelength (i.e. the harder the x-ray) the more dangerous it is. This is why lower energy x-rays are used in medical imaging. The x-rays will typically ionize smaller atoms, while larger atoms can absorb the radiation as they have larger gaps in their ionization energies. This is why x-ray machines will image things like bones very well (they are composed of heavier elements) while they are poor imagers of soft tissue (lighter elements). It is estimated that x-ray machines, and other derivative devices, account for between 35-50% of the ionizing radiation experienced by people in the United States.Alpha Particles: An alpha particle (designated by the Greek letter ÃŽ ±) consists of two protons and two neutrons; exactly the same composition as a helium nucleus. Focusing on the alpha decay process that creates them, heres what happens: the alpha particle is ejected from the parent nucleus with very high speed (therefore high energy), usually in excess of 5% of the speed of light. Some alpha particles come to Earth in the form of cosmic rays  and  may achieve speeds in excess of 10% of the speed of light. Generally, however, alpha particles interact over very short distances, so here on Earth, alpha particle radiation is not a direct threa t to life. It is simply absorbed by our outer atmosphere. However, it is a danger for astronauts.  Beta Particles: The result of beta decay, beta particles (usually described by the Greek letter Î’) are energetic electrons that escape when a neutron decays into a proton, electron, and anti-neutrino. These electrons are more energetic than alpha particles but less so than high energy gamma rays. Normally, beta particles are not of concern to human health as they are easily shielded. Artificially created beta particles (like in accelerators) can penetrate the skin more readily as they have considerably higher energy. Some places use these particle beams to treat various kinds of cancer because of their ability to target very specific regions. However, the tumor needs to be near the surface as not to damage significant amounts of interspersed tissue.Neutron Radiation: Very high-energy neutrons are created during nuclear fusion or nuclear fission processes. They can then be absorbe d by an atomic nucleus, causing the atom to go into an excited state and it can emit gamma-rays. These photons will then excite the atoms around them, creating a chain-reaction, leading to the area to become radioactive. This is one of the primary ways humans are injured while working around nuclear reactors without proper protective gear. Non-ionizing Radiation While ionizing radiation (above) gets all the press about being harmful to humans, non-ionizing radiation can also have significant biological effects. For instance, non-ionizing radiation can cause things like sunburns. Yet, it is what we use to cook food in microwave ovens.  Non-ionizing radiation can also come in the form of thermal radiation, which can heat material (and hence atoms) to high enough temperatures to cause ionization. However, this process is considered different than kinetic or photon ionization processes. The Karl Jansky Very Large Array of radio telescopes is located near Socorro, New Mexico. This array focuses on radio emissions from a variety of objects and processes in the sky. NRAO/AUI Radio Waves: Radio waves are the longest wavelength form of electromagnetic radiation (light). They span 1 millimeter to 100 kilometers. This range, however, overlaps with the microwave band (see below). Radio waves are produced naturally by active galaxies (specifically from the area around their supermassive black holes), pulsars and in supernova remnants. But they are also created artificially for the purposes of radio and television transmission.Microwaves: Defined as wavelengths of light between 1 millimeter and 1 meter (1,000 millimeters), microwaves are sometimes considered to be a subset of radio waves. In fact, radio astronomy is generally the study of the microwave band, as longer wavelength radiation is very difficult to detect as it would require detectors of immense size; hence only a few peer beyond the 1-meter wavelength. While non-ionizing, microwaves can still be dangerous to humans as it can impart a large amount of thermal energy to an item due to its interactions with water and water vapor. (This is also why microwave observatories are typically placed in high, dry places on Earth, as to lessen the amount of interference that water vapor in our atmosphere can cause to the experiment.Infrared Radiation: Infrared radiation is the band of electromagnetic radiation that occupies wavelengths between 0.74 micrometers up to 300 micrometers. (There are 1 million micrometers in one meter.) Infrared radiation is very close to optical light, and therefore very similar techniques are used to study it. However, there are some difficulties to overcome; namely infrared light is produced by objects comparable to room temperature. Since electronics used to power and control infrared telescopes will run at such temperatures, the instruments themselves will give off infrared light, interfering with data acquisition. Therefore the instruments are cooled using liquid helium, so as to lessen extraneous infrared photons from entering the detector. Most of what the Sun emits that reaches Earths surface is actually infrared light, with the visible radiation not far behind (and ultraviolet a distant third). An infrared view of a cloud of gas and dust made by Spitzer Space Telescope. The Spider and Fly Nebula is a star-forming region and Spitzers infrared view shows structures in the cloud affected by a cluster of newborn stars. Spitzer Space Telescope/NASA Visible (Optical) Light: The range of wavelengths of visible light is 380 nanometers (nm) and 740 nm. This is the electromagnetic radiation that we are able to detect with our own eyes, all other forms are invisible to us without electronic aids. Visible light is actually only a very small part of the electromagnetic spectrum, which is why it is important to study all other wavelengths in astronomy as to get a complete picture of the universe and to understand the physical mechanisms that govern the heavenly bodies.Blackbody Radiation: A blackbody is an object that emits electromagnetic radiation when it is heated, the peak wavelength of light produced will be proportional to the temperature (this is known as Wiens Law). There is no such thing as a perfect blackbody, but many objects like our Sun, the Earth and the coils on your electric stove are pretty good approximations.Thermal Radiation: As particles inside of a material move due to their temperature the resulting kinetic energy can be described as the total thermal energy of the system. In the case of a blackbody object (see above) the thermal energy can be released from the system in the form of electromagnetic radiation. Radiation, as we can see, is one of the fundamental aspects of the universe. Without it, we would not have light, heat, energy, or life. Edited by Carolyn Collins Petersen.

International Events Involving The U.s. Military Essay

The 20th century entailed many ups and downs, such as the fall of the Standard Oil Company by President William Taft, creator of the first assembly line by Henry Ford, and the opening of the Panama Canal. Most importantly, the U.S. along with other allies entering World War I and II showed just how dominant the U.S. was, both domestically and internationally. Showing pure dominance over other countries, the U.S. became the Policemen of the World, which is still thriving today. This paper will describe international events involving the U.S. military that can be traced back to a foreign policy created after the Civil War, as well as aspects of U.S. history since 1865 that have led to the U.S. s rise as a world super power policeman. International incidents since WWII that America has taken on a policing role will also be discussed. Lastly, driving forces that fueled international policy decisions for the events mentioned will be discussed. The President Theodore Roosevelt s decisive way to deal with Latin America and the Caribbean has regularly been described as the Enormous Stick, and his arrangement came to be known as the Roosevelt Corollary to the Monroe Doctrine. President Theodore Roosevelt In spite of the fact that the Monroe Doctrine of 1823 was basically latent (it asked that Europeans not expand their impact or recolonize any part of the Western Hemisphere), by the twentieth century a more sure United States was eager to go up against the part of provincialShow MoreRelatedThe League Of Nations And The United Nations1178 Words   |  5 PagesIntroduction The League of Nations and the United Nations are two unique forms of international governance created by world powers out of the same necessity—needing a better format of managing global conflict. However, both international organizations were created, structured, and operated under very different circumstances. For instance, the League of Nations was created during towards the end of World War I, when nations were looking for a governing body to address future global conflicts. SimilarlyRead MoreForeign Policy Essay599 Words   |  3 PagesPolicemen of the World Thesis and Outline Janene Bull Professor Joel A. Goldstein Contemporary US History 2/22/2015 The evolution of U.S. Foreign policy following the Civil War is continually evolving. During the Civil War years, America had an economy that was based on agriculture. Farmers were growing cotton, tobacco and sugarcane. Slaves from Africa worked on these enormous plantations. . At the time, America was in an election year with Lincoln as the candidate of the Republican PartyRead MoreThe United States Government1309 Words   |  6 Pagesgovernment was formed to create a democracy fit for the idea that they would be considered â€Å"land of the free.† Unfortunately, throughout the history of several world wide events, the intentions of the â€Å"forefathers† have strayed to manipulate events and people. The government has been accused for many past years of lying when main events strike the nation causing many tragedies as well as causing emotional anguish on the world. Many claims of false accusations are typically only made public after severalRead MoreThe United States Has Engaged In Numerous International1349 Words   |  6 Pagesnumerous international interventions in the Middle East. The two major events that have shaped the politics of U.S. foreign policy, Israel, and the Arab states are the Suez Crisis of 1956 and the Six Day War of 1967. President Eisenhower and President Johnson each took different approaches while confronting these crises. The personalities, motives and predispositions of the Presidents and their circle of closest advisors explain how they shaped their policies and how they responded to the events. TheRead MoreRelations Between China And The United States Essay1451 Words   |  6 PagesThe events that have taken place over the past couple of centuries, and more so the past decade, have monumentally impacted the relationship between the United States and China for better and for worse. Today, China and the U.S. have evolved into two of the most elite superpowers in the world, and they classify as some of the most prominent leaders in economics, military, technology, and universal innovation. Currently, the United States is just weeks away from electing their next president, cyber-attacksRead MoreAttack on the Marine Corps Barracks in Beirut1603 Words   |  6 Pagestruck full of explosives attacked military barracks and killed 241 servicemen (including 220 U.S. Marines) in Beirut, Lebanon. The blast was the biggest known non-nuclear explosion since World War II and was the bloodiest day since Iowa Jima, according to Rick Hampson writing in USA Today. The Marines had been sent to Lebanon as peace-keepers, trying to bring some peace to a civil war that was ongoing in Lebanon. Military observers subsequent to that horrific event have suggested that this terroristRead More Impact of Reducing Global U.S. Troop Deployment Essay1412 Words   |  6 PagesUnited States military is the strongest military that the world has ever seen. However if it is to continue to remain a dominant power it must remain in key positions throughout the world. The United States military is used for more than just fighting the nations wars, it is also used as a diplomatic tool, a deterrent, and to assist in stabilizing the world economy. The effects of reducing U.S. troop presence around the world will have repercussions in more aspects than simply military strength. Read MoreRealism During the 1994 Rwanda Genocide1215 Words   |  5 Pages Realism is one of the oldest and most popular theories in International Relations. It offers a perspecti ve about competition and power, and can be used to explain the actions between states. An example of realism is the U.S. reaction – or lack thereof – during the 1994 Rwandan genocide. All branches of realism share some central tenets. Realists believe that the world exists in a state of anarchy. Since there is not a world government to keep states from attacking each otherRead MoreHomeland Security And Homeland Defense1321 Words   |  6 PagesIntroduction Since the September 11, 2001 events, the United States of America gravitated towards a more aggressive approach in its security. The result of the tragic events was the establishment of homeland security. The White House, the federal government and the Congress joined together to establish it. On September 20, 2001, President George W. Bush issued an executive order 13228 to establish an Office of Homeland Security within the White House and assigning the Governor of PennsylvaniaRead MoreWar Between Countries And The Time Frame Of The Vast Advancements Essay933 Words   |  4 Pageslearn about why certain events happened in time and the impact that resulted. The topic war, in particular, is the most fascinating thing that occurs throughout history to me because of the fact that it has been used as a way to dispute conflicts between countries and the time frame of the vast advancements that have been made in weaponry in the past one hundred years. I feel I have accumulated basic knowledge about war throughout my high school years by taking world and U.S history courses. These

Prevention Free Essays

Prevention can be taken to mean, a process of offering advice, guiding and educating a certain group of people in the name of promoting their well being in the society. It is a critical decision one makes to meet the choice aimed at meeting ones challenges of life by creating a condition favorable to promote good lifestyles and healthy behaviors. Prevention of diseases involves three levels, according to the stages of the target disease (Sieving 1997). We will write a custom essay sample on Prevention or any similar topic only for you Order Now They are primary, secondary and tertiary levels. Primary level is the process by which various methods are used in to avoid a person initiating a p disease (Piccinino   1998). They are used prior to that person getting the disease. Methods used in this level would be like, campaigns from public service, school and community programs and of course constant communication with the intended group. This helps in avoidance of the disease. According to (Sieving 1997) the second level of prevention is the secondary level that is used in the early stages of disease detection. In this case the disease has already occurred in the person but the patient is not aware the main objective of this level is to detect and treat the disease early enough. Tertiary level of prevention aims at reducing the negative consequences of the disease already in the person. It helps to slow down the rate of spreading the infections or complications in that it prevents pain from the disease. Public health programs are the set activities by the government or other organizations with intentions of meeting certain objectives in health prevention. Health programs aims at reducing incidences of diseases, improving the social conditions of a person .One of the most common activity in the health programs is vaccination. Public health programs go hand in hand with levels of prevention. One of the major problems today is how to cope with the high rate of adolescent pregnancy. This issue can be addressed by using various programs to create awareness. It can also fit in all the levels of prevention though sutes best in the primary level of prevention. Despite the fact that the teen rate of pregnancy has declined by a big margin in U.S. Since early 1990s, it is said and justified that over 1 million Americans adolescent girls get pregnant. Many of these pregnancies are usually accidental or unplanned though others are usually intended It is said that about fifty percent of teenage girls who were once pregnant become pregnant again within two years. It is also said that the second baby of the teenage girl is usually at a risk of being underweight and at the same time there is the high chance of drop out in school. (Piccinino 1998) There are a number of public health programs that are being developed at least from each level of prevention targeted to children and adolescent boys and mainly girls. According to (Aboma 1998) ( Joseph 1999) This may include abstinence programs, school-based sexuality programs, Involvement by the community, family planning clinics, school-based programs and public healthcare programs. (Aboma 1997) Many of these programs call for either abstinence or use of contraceptives. Abstain ace could be the best method however, adolescents don’t take it as a reality .Some institutions have criticized the issue of using contraceptives arguing that it promotes sexual engagement.( Piccinino 1998) observes   that,   a survey has shown that contraceptives like condoms do not motivate teens to engage in sex and thus they should be introduced in schools. The initiative by the community can help reduces the high rate of illiteracy .Parents have a greater influence on their adolescents on either becoming pregnant or impregnating. Parents communicating with their children freely about issues they come across like sex, relationships and love ( Aboma 1998). As parents one should talk to them what you feel about this issues, be honest to them have courage to tell them the truth that having an early pregnancy is risky to both the child and the teenage herself. In case she is already pregnant, let her know her responsibilities like visiting a prenatal care center, avoid drugs especially smoking and to eat nutritional food (Sonenstein 1998). Parents ought to be opening minded and begin a talk concerning these issues; if you are not capable, use other methods like letting them watch a video or a movie. There is the need to super vice your children as they grow up to adolescence and give them lots of guidance counseling (Sonenstein 1998). This should be for both the boy and the girl .The secondary and tertiary level of prevention could constitute the issues of caring for the born child and more so the teen. There is the need to have programs that will address this issue. The tertiary level of prevention can really help at this stage (Aboma 1997). There is the importance developing programs that would look at issues of child-rearing responsibilities, relationships with their friends and the rest of the community. Educational activity programs, counseling and life skills training need to be developed (Sieving 1997). These educational programs would include offering remedial classes for the teen parents, family planning, parenting skills, food and nutritional advices for both the child and the mother In conclusion, prevention is a process involved in offering guidance and educating a certain group of people with an aim of promoting their wellbeing. It has three levels consisting of the primary level-prevents occurring of diseases, secondary level-aimed at detecting early diseases and tertiary-help the patient cope with the already established problem. In the case of the teenage pregnant group, all the three levels of prevention can help them to cope with the situation, and even prevent further occurrences if proper programs are put in place. References Aboma CD (1999). State-Specific Pregnancy Rates Among Adolescents—United States, 1992-1998, Oxford University press. pp 45-67, 77 Aboma JC, Chandra A, Mosher WD, Peterson LS, Piccinino LJ (1997.). Fertility, Family Planning, and Women’s Health, New York. Abma J, Driscoll A, Moore K. (1998). Young Women’s Degree of Control over First Intercourse: An Exploratory Analysis. Family Planning Perspectives 30(1):12-18. 1998. Piccinino LJ, Mosher WD (1998.). Trends in Contraceptive Use in the United States: 1982-1998. Family Planning Perspectives, Oxford University press: 4-10, 46 Sieving R, Shew M, Ireland M, Bearinger L, Udry JR (.1997.)   Protecting Adolescents from Harm: Findings from the National Longitudinal Study on Adolescent Health. London pp57-97 Sonenstein FL, Ku L, Lindberg LD, Turner DF, Pleck JH (1998.). Changes in Sexual Behavior and Condom Use among Teenaged feMales: 1988 to 1996.   London.pp 956-959, Ventura SJ, Mathews TJ, Curtin SC. (1998) Teenage Births in the United States: New York pp 66-79.       How to cite Prevention, Essay examples

Violent Media is Good for Kids free essay sample

Gerard Jones essay â€Å"Violent Media is Good for Kids† was a very interesting paper. He opens with a story of him as a child, â€Å"alone and afraid† of the rage that was inside of him. His parents taught him that violence was wrong and that rage was something that could be simply overcome. Jones main argument was aimed at parents, saying that they are stifling a childs natural instinct of anger and rage. He wrote that â€Å"we send the message to our children in a hundred ways that their craving for imaginary gun battles and symbolic killing is wrong†, and uses his own childhood as an example of how comics were good for him because they were juvenile and violent. I feel that his explanation of our fear of â€Å"youth violence† is logically sound, and I agree with him that violent media can actually help children. Jones states the children will feel rage. Then, he uses the powerful tool of rebuttal to show the credibility of his argument. Throughout the essay, Jones discusses his past with violent media. He begins with discussing his professional career as a comic book writer. Later, Jones mentions his three-year long project with Dr. Melanie Moore, a psychologist who works with urban teens. This project produced Jones’s most useful tool in using violent media for good. According to Jones, his program, Power Play, â€Å"helps young people improve their self-knowledge and sense of potency through heroic, combative storytelling† (Jones). Discussing his past with the realm of violent media makes the audience feel like Jones is a competent and trustworthy source on the matter. To further contribute to ethos, Jones uses a rebuttal. In his essay, he mentions that many psychologists argue that violent stories breed more violence- such as the recent increase in columbine shootings. They say people use media violence as a driving force for real life violence. Jones acknowledges these points. However, he refutes them by saying that â€Å"it’s helped hundreds of people for everyone its hurt, and it can help far more if we learn how to use it† (Jones). In other words, when we channel violent media into heroic battles of good versus evil, it can empower a child in need. This rebuttal contributes to the objectivity of the essay. It shows that the author did his research so well that he can recognize opposing viewpoints and refute them. The author also effectively supports his thesis through pathos. To evoke strong emotion in his readers, Jones appeals to the audience’s feeling of vulnerability in their youth. Recognizing that during adolescence most people feel powerless, he tells engaging stories of his own and his son’s rise to power through comic books to give the audience something to connect to. As these stories are told, readers reminisce about those days, and feel joy in knowing that there was a happy ending. The feelings created make the audience look positively at the essay and relate to it. Lastly, Jones uses logos to solidify his argument with concrete evidence. This is done by giving two real-life examples of girls that were helped through childhood by writing violent media. In both cases, Jones personally assisted these girls during a difficult time, and got them started on their path to future successes. The first example involves a little girl, Emily, whose parents were separated. Her main problem was her violent fantasies. Because she didn’t have a proper outlet, she acted out aggressively. Jones stepped in and channeled her fantasies into stories. At the end of the day, she was still fiery and strong, but she was able to control herself in public. In fact, she even became a student leader in her school. In this case, violent media gave a child an outlet for her aggression. The second example involved an older girl in a very chaotic family situation. She was surrounded by fighting, alcohol, and peer pressure. Jones stepped in with the power of writing. His use of the Power Play program helped the girl escape from her reality. In the girl’s stories, she was powerful and invulnerable. She was able to ignore the world going on around her for a period of time. This proved to be very beneficial. She stayed out of trouble, and grew up to be a writer and political activist. In this case, Jones showed how media violence helped someone power through adolescence and contribute to a very successful future. Jones uses the two examples above to drive home his argument. By employing real life examples, he is able to not only provide concrete evidence, but also put a face to the fact. Instead of spewing a list of facts, he gives two examples the audience could relate to and better visualize. This makes for a stronger use of logos. It seems that Gerald Jones had his work cut out for him in writing this essay. He had to take the hardwired belief that violence is bad and convince the world that â€Å"Through immersion in imaginary combat and identification with a violent protagonist, children engage the rage they’ve stifled, come to fear it less, and become more capable of utilizing it against life’s challenges† (Jones). By using ethos to give credibility to himself and his argument, pathos to evoke strong emotion and connect the reader to the essay, and logos to make the argument solid, Jones is able to effectively argue his thesis. Work Cited Jones, Gerard. â€Å"Violent Media is Good for Kids. † Current Issues and Enduring Questions. 9th Edition. Sylvan Barnet and Hugo Bedau, Eds. Boston: Bedford St. Martin’s Press, 2011. 195-199. Print.