Astronomy 101 - Learning About Stars

Astronomers are often asked about objects in the cosmos and how they came to be. Stars, in particular, fascinate many people, particularly because we can look out on a dark night and see so many of them. So, what are they? Stars are massive shining spheres of hot gas. Those stars you see with your naked eye in the night sky all belong to the Milky Way Galaxy, the huge system of stars that contains our solar system. There are around 5,000 stars which can be seen with the naked eye, though not all stars are visible at all times and places. With a small telescope, hundreds of thousands of stars can be seen. Larger telescopes can show millions of galaxies, which can have upwards of a trillion or more stars. There are more than 1 x 1022 stars in the universe (10,000,000,000,000,000,000,000). Many are so large that if they took our Suns place, they would engulf Earth, Mars, Jupiter, and Saturn. Others, called white dwarf stars, are around the size of Earth, and neutron stars are less than about 16 kilometers (10 miles) in diameter. Our Sun is about 93 million miles from Earth, 1 astronomical Unit (AU). The difference in its appearance from the stars visible in the night sky is due to its close proximity. The next closest star is Proxima Centauri, 4.2 light-years (40.1 trillion kilometers (20 trillion miles) from Earth. Stars come in a wide variety of colors, ranging from deep red, through orange and yellow to an intense white-blue. The color of a star depends on its temperature. Cooler stars tend to be red, while the hottest ones are blue. Stars are classified many ways, including by their brightness. They are also divided into brightness groups, which are called magnitudes. Each star magnitude is 2.5 times brighter than the next lower star. The brightest stars now represented by negative numbers and they can be dimmer than 31st magnitude.   Stars - Stars - Stars Stars are primarily made of hydrogen, smaller amounts of helium, and trace amounts of other elements. Even the most abundant of the other elements present in stars (oxygen, carbon, neon, and nitrogen) are only present in very small quantities. Despite the frequent use of phrases like the emptiness of space, space is actually full of gases and dust. This material gets compressed by collisions and blast waves from exploding stars, causing lumps of matter to form. If the gravity of these protostellar objects is strong enough, they can pull in other matter for fuels. As they continue to compress, their internal temperatures rise to the point where hydrogen ignites in thermonuclear fusion. While the gravity continues pulling, trying to collapse the star into the smallest possible size, the fusion stabilizes it, preventing further contraction. Thus, a great struggle ensues for the life of the star, as each force continues to push or pull. How Do Stars Produce Light, Heat, and Energy? There are a number of different processes (thermonuclear fusion) which make stars produce light, heat and energy. The most common happens when four hydrogen atoms combine into a helium atom. This releases energy, which is converted to light and heat. Eventually, most of the fuel, hydrogen, is exhausted. As the fuel begins to run out, the strength of the thermonuclear fusion reaction declines. Soon (relatively speaking), gravity will win and the star will collapse under its own weight. At that time, it becomes what is known as a white dwarf. As the fuel further depletes and reaction stops all together, it will collapse further, into a black dwarf. This process can take billions and billions of years to complete. Toward the end of the twentieth century, astronomers began to discover planets orbiting other stars. Because planets are so much smaller and fainter than stars, they are difficult to detect and impossible to see, so how do scientists find them? They measure tiny wobbles in a star’s motion caused by the gravitational pull of the planets. Although no Earth-like planets have been discovered yet, scientists are hopeful. Next lesson, well take a closer look at some of these balls of gas.

Tina and Dan-Birth Control Methods Essay - 875 Words

Tina and Dan are considering various birth control methods. They are a newly-wed couple who practiced abstinence before marriage and plan on starting their family with a year. Choose possible methods of contraception for the couple and discuss the advantages and disadvantages they would need to consider at the point in their lives. Due to the fact that Tina and Dan are newly-wed it would be safe to assume their sexual activities with each other will be plentiful. Considering the fact they practiced abstinence prior to their marriage, it should also be safe to assume they are both free from STI or HIV/AIDS. Under these circumstances I would recommend the birth-control pill. The greatest advantage of using the pill, when used properly,†¦show more content†¦These include hypertension, diabetes, migraine headaches, uterine fibroids, and elevated cholesterol level (Voelker, 2000). Linda is a young single woman with an active dating life. She chooses to be intimate only with long-term committed partners. She is wary of the risks associated with sexually transmitted infections and has decided that she does not want to be a single parent. Choose possible methods of contraception for Linda and discuss the advantage and disadvantages she should consider at this point in her life. I would recommend that Linda use condoms and a spermicide. Although condoms are not 100% effective for the protection against STIs, HIV/AIDS, or pregnancy, it is the best prevention available for those who are sexually active. Some condoms are made of latex; while others are made of intestinal membranes of lambs. For Linda I believe latex condoms are best for her. The skins are thinner and do not protect as well as the latex condoms. Although Linda is intimate with long-term commitments there is a plural there, meaning other relationships have not worked out and she has moved on to another relationship. Not only is there a number of partners for Linda but Linda dont know about the other partners her new partners have been with. Among the advantages for the use of condoms and spermicide is the effectiveness rivals that of the birth-control pill when used correctly andShow MoreRelatedProduct Placement10682 Words   |  43 Pagesfrom the television industry in the 1950s than they do with traditional films.[10] Gurevitch suggests that as a result, the relationship between cinema and advertising is more intertwined than previous historians have credited, suggesting that the birth of cinema was in part the result of advertising and the economic kickstart that it provided early film makers.[11] Kerry Segrave details the industries that advertised in these early films and goes on to give a thorough account of the history of productRead MoreProduct Placement10670 Words   |  43 Pagesfrom the television industry in the 1950s than they do with traditional films.[10] Gurevitch suggests that as a result, the relationship between cinema and advertising is more intertwined than previous historians have credited, sugge sting that the birth of cinema was in part the result of advertising and the economic kickstart that it provided early film makers.[11] Kerry Segrave details the industries that advertised in these early films and goes on to give a thorough account of the history of productRead MoreLibrary Management204752 Words   |  820 Pagesand Joseph R. Matthews The Complete Guide to Acquisitions Management Frances C. Wilkinson and Linda K. Lewis Organization of Information, Second Edition Arlene G. Taylor The School Library Media Manager, Third Edition Blanche Woolls Basic Research Methods for Librarians Ronald R. Powell and Lynn Silipigni Connoway Library of Congress Subject Headings: Principles and Application, Fourth Edition Lois Mai Chan Developing Library and Information Center Collections, Fifth Edition G. Edward Evans and Margaret

Case Study 2 Free Essays

Chapter 2 Case Study Summary 1: 21-year old woman that has had type 1 diabetes for the past 8 years, was brought to the hospital in a coma. She was prescribed to take 92 units of insulin a day to maintain her sugar levels within normal limits and prevent excess sugar in her urine. Upon admission she was hypontensive, tachycardic and hyperventilating. We will write a custom essay sample on Case Study 2 or any similar topic only for you Order Now Her labs show she is acidonic, arterial blood carbon dioxide levels were low, blood oxygen tension is normal, bicarbonate levels are really low indicating metabolic acidosis, low sodium levels, slightly high level of potassium, Chloride level is on the low end of normal, very high levels of blood urea and nitrogen, total carbon dioxide levels are really low, extremely high sugar levels and high creatinine levels. She tested positive for ketones. She recieved 8 units of regular insulin through an IV and 8 units per hour by IV infusion pump. Her blood sugar levels began to drop at about 100 mg/dL each hour. After seven hours her breathing and pH went back to normal, following an injection of intravenous sodium bicarbonate to raise her pH and vigorous IV fluids and electrolyte replacement. 1. It seems her type 1 diabetes is uncontrolled. As her body could not use the sugar and there is not enough insulin, fat was used for fuel instead. During fat breakdown, byproducts called ketones are developed. Ketone bodies are acidic and dangerous when it build up in the body causing all her symptoms upon admission. . Yes, her pH levels became normal. Meaning her bicarbonate levels increased to compensate for the increased hydrogen proton levels in her blood. 3. When the body uses fat for energy instead of sugar, the body creates a byproduct called ketones. Since this is a byproduct, it flows through the renal system waiting to be expelled from the body. Normally, the existence of ketone bodies are detected through a urine sample. 4. The potassium results were high which can indicate some problem with her kidneys. 5. The low sodium results are based on the fact that sodiums job in the body is to keep proper acid-base equilibrium (homeostasis). Sodium has alkaline properties so if the levels are low the acid levels will be higher. 6. Diabetes can affect normal control of BP and can cause damage to the nerves supplying the blood vessels. When the blood pressure lowers the glomerular filtration rate decreases. 7. Anion gap measures of anions in the arterial blood. Anion gap equals chloride plus bicarbonate minus sodium Na-(Cl + HCO3-). The patient has a anion gap of 30. Normal levels are 7 to 16. 8. Osmolality measures the concentration of all chemical particles found in the fluid part of blood. Normal values range from 275 to 295. The patient has a osmolality of 351. 1 Summary 2: 14 year old boy that was never vaccinated against poliomyelitis got the disease late summer. He was hospitalized and needed a respirator during the severity of the illness. Once he began to recover, they took him off the respirator with no apparent effects. Days later a blood analysis revealed the following. H level is slightly acidic, carbon dioxide levels are high and indicate some respiratory acidosis, blood oxygen level is low, bicarbonate level is high, sodium levels are normal, potassium is normal, chloride level is slightly low, and total carbon dioxide levels are high. 1. It seems the patient has respiratory acidosis. Production of carbon dioxide occurs fast and the failure of proper ventilated increases the CO2 in the blood. 2. B uffers are normal compensatory mechanisms to respond to the acidosis. 3. Yes, the HCO3 (bicarbonate) test is elevated and bicarbonate is a buffer. 4. Acute respiratory acidosis is when a abrupt failure of ventilation occurs. Chronic respiratory acidosis may be secondary to many disorders. 5. Total CO2 measures the serum bicarbonate and available forms of carbon dioxide. Bicarbonate takes up about 95% of the total. They take the bicarbonate measurements by the sample of the venous blood and arterial blood gas analysis. 6. Chloride levels are slightly lower due to respiratory muscle weakness. How to cite Case Study 2, Free Case study samples Case Study 2 Free Essays Case Study 2 Springfield Express is a luxury passenger carrier in Texas. All seats are first class, and the following data are available: Number of seats per passenger train car 90 Average load factor (percentage of seats filled) 70% Average full passenger fare $ 160 Average variable cost per passenger $ 70 Fixed operating cost per month $3,150,000 Formula : Revenue = Units Sold * Unit price Contribution Margin = Revenue – All Variable Cost Contribution Margin Ratio = Contribution Margin/Selling Price Break Even Points in Units = (Total Fixed Costs + Target Profit )/Contribution Margin Break Even Points in Sales = (Total Fixed Costs + Target Profit )/Contribution Margin Ratio Margin of Safety = Revenue – Break Even Points in Sales Degree of Operating Leverage = Contribution Margin/Net Income Net Income = Revenue – Total Variable Cost – Total Fixed Cost Unit Product Cost using Absorption Cost = (Total Variable Cost + Total Fixed Cost)/# of units a. Contribution margin per passenger =$160 – $70 = $90 Contribution margin ratio =$90/$160=56. We will write a custom essay sample on Case Study 2 or any similar topic only for you Order Now 25% Break-even point in passengers = Fixed costs/Contribution Margin = $ 3,150,000/$90 Passengers =35,000 Break-even point in dollars = Fixed Costs/Contribution Margin Ratio = $ 3,150,000/56. 25% $ 5,600,000 b. Compute # of seats per train car (remember load factor? )= 90 * 70% = 63 Seats filled Compute # of train cars (rounded) = 35,000/63 = 556 train cars filled c. Contribution margin = $190 – $70 = $120 Break-even point in passengers = fixed costs/ contribution margin =$ 3,150,000/$120 Passengers = 26,250 BE = 90 seats *60% = 54 Train cars (rounded) = 26,250/54 = 486 d. Contribution margin = $190 – $90 = $70 Break-even point in passengers = Fixed costs/Contribution Margin = $ 3,150,000/$70 Passengers =45,000 BE = 90 seats *70% = 63 Train cars (rounded) = 45,000/63 = 714 e. Contribution margin = $205 – $85 = $120 (P = Passengers) Sales205*P Variable Exp. 085*P Contribution M. 120*P Fixed Exp. 3,600,000 PretaxX Tax Exp. :X*30% Net Income Op. 750,000 750,000 = X – 0. 3X (X (1 – 0. 3) = 750,000/(1-0. 3) = X X=$ 1,071,428. 57 (Pre-Tax) $ 1,071,429= 120P – $ 3,600,000 = $ 1,071,429 + $ 3,600,000= 120P = 4,671,429/120= P P =38,928 f. Contribution margin = $120 – $70 = $50 # of discounted seats = 90*70%; 90*80% ( Difference is 10%; 90*10% = 9 Seats Contribution margin for discounted fares X #discounted seats = $50 * 9 Seats = $450 50 Train *$ 450 train cars per day * 30 days per month= $675,000 $ 675,000 (-) $ 180,000 additional fixed costs = $495,000 pretax income. g. 1. Co mpute Contribution margin Route 1 Route2 Overall Mix Sales160*P175*P335 *p Variable Exp. 070*P070*P140 *p Contribution M. 090*P105*P195 *P Route 1 Contribution Margin Ratio =$90/$160=56. 5% Route 2 Contribution Margin Ratio =$105/$175=60% Overall Contribution Margin Ratio =$195/$335=58. 20% Answer: Yes, it should, because the CMR is greater with the two routes. 2. BE = 90 * 60% = 54 Seats filled Contribution margin = $175 – $70 = $105 (P = Passengers) Sales175*P (54 Seats) Variable Exp. 070*P Contribution M. 105*P Fixed Exp. 3,150,000+250,000=3,400,000 Pretax120,000 120,000 = (105P*(54 Seats)) – 3,400,000 = 3,520,000 = 5,670P = 3,520,000/5,670 = P P=621 621/54 =12 train cars 3. Contribution margin = $175 – $70 = $105 BE = 90 seats *75% = 68 Contribution margin = $175 – $70 = $105 (P = Passengers) Sales175*P (68 Seats) Variable Exp. 070*P Contribution M. 105*P Fixed Exp. 3,150,000+250,000=3,400,000 Pretax120,000 120,000 = (105P*(68 Seats)) – 3,400,000 = 3,520,000 = 7,140P = 3,520,000/7,140= P P=493 493/68 = 7 train cars 4. Springfield should consider Qualitative factors such as: (1) effect on employee morale, schedules and other internal elements; (2) relationships with and commitments to older and new suppliers; (3) effect on present and future customers; and (4) long-term future effect on profitability and new businesses. How to cite Case Study 2, Free Case study samples