Answers to Questions in Astronomy Essay Example for Free

Answers to Questions in Astronomy Essay 1. How do astronomers measure the distances to galaxies and how does that allow the sizes, luminosities and masses of galaxies to be determined? A distance indicator is an object within a galaxy that functions as a marker to that galaxy. It may be a Cepheid star, globular cluster, H II region, planetary nebula or supernova. The distance to a galaxy, especially if it is very far away, is approximated by employing the Hubble Law which is expressed as Recession Velocity (Vr) = Hubble’s Constant (H) x distance (d). After obtaining the distance, it is possible to determine diameter through the small angle formula and luminosity from distance and apparent magnitude where both formulas are derived equations (Garber). Meanwhile mass can be estimated in three ways. Rotation curves reveal the calculation of rotational velocities for varying distances from the galactic center so that once distance and velocity are known, mass can be obtained (Garber). Another is through the cluster method which focuses on the motion of a galaxy within a galactic cluster. The size of the galaxy as well as range of velocity determines the total mass of the cluster (Garber). The third is through the velocity dispersion method where the spectra of the galaxy are used to approximate mass. Broad spectral lines indicate high velocity which in turns suggests a large mass (Garber). 2. Discuss how individual stars and the shapes of galaxies are affected by collisions. As a galaxy approaches another in a collision, the gravitational fields of the stars in each of them start to interweave and the resulting powerful tidal forces disturb and radically alter the shape of the galaxy, similar to the manner in which the gravitational pull of the moon causes the tide to rise in regions of the earth nearest to it but magnified a thousand times. A collision initiates the formation of tidal tails, bars or rings and colliding gas clouds produce knots of newly formed blue stars while the nucleus of the galaxy becomes deformed (sciencedaily.com). On the other hand, when stars collide, they merge together as one star that displays unusual brightness and heat relative to age so that they become very prominent in their globular cluster. These stars are referred to as â€Å"blue stragglers†. When stars increase in age and use up their hydrogen, they become cooler, less massive and red in color but through collisions, they obtain extra mass causing them to turn blue (Masters). This permits them to remain longer in the main sequence the phase in a star’s life where it burns its hydrogen. 3. Explain the differences between the three types of galaxies and what happens to change their shape. An elliptical galaxy is rounded or oval in shape, do not have visible gas and dust or bright, hot stars and consists of population II stars. Elliptical galaxies are also surrounded by globular clusters. A spiral galaxy has a disc component, consists of both populations of stars, exhibits a nucleus and may have arms with differing orientations (Garber). An irregular galaxy does not present a regular pattern and includes new and old stars alike. Galactic interaction, collision and merging, which involve the effects of the gravitational fields of galaxies, are the primary events that change the shape of galaxies. The subsequent structure depends on both the type of the galaxies involved and the directions of their orbits (Keel). Collision, mentioned earlier, may not result in a merger if both galaxies have enough force to continue moving away from each other after the event. Galaxies are said to be interacting when they do not collide but both their gravitational attractions cause distortion and exchange of gas and dust (astro.umd.edu). In interactions that occur at slow speeds and involve galaxies with unequal masses, spiral formations may assume irregular-lenticular shapes (Than). Gases being pulled to the central region, as a result of tidal disturbances, clear away the spiral configuration, leaving behind a disk structure. The most drastic interaction is the merging of two galaxies and occurs when they collide but lose their momentum to slide past one another. Instead, they fall back into each other and unite into one galaxy, losing their original shapes in the process (astro.umd.edu). When a significantly more massive galaxy collides and merges with a smaller one in a type of interaction known as galactic cannibalism, the bigger galaxy does not exhibit a visible change in shape but the less massive galaxy is ripped apart, loses its shape and becomes integrated into the bigger one.

Archimedes Essay example -- Biographies Bio Biography

Archimedes was born in Syracuse, Sicily, in 287 B.C. His father was Philas, an aristocratic astronomer. He was educated in Alexandria, Egypt; where he met the Alexandrian scholars Conon of Samos and Eratosthenes of Cyrene. For much of his life, Archimedes kept a correspondence with these two scholars, updating them on his most recent discoveries and proofs. Archimedes spent the major part of his life in Sicily, in and around Syracuse. He did not hold any public office but devoted his entire lifetime to research and experiment. Archimedes is credited with the invention of the compound pulley, the hydraulic screw, the burning mirror, and vast improvements made on the catapult. He calculated the exact value of pi, proved that the volume of a sphere is 2/3 that of the circumscribed cylinder, and defined the law of the lever. Perhaps one of Archimedes’ most famous discoveries is the discovery of the hydrostatic principle now called the Archimedes principle. There are three different accounts of Archimedes’ death in 212 B.C. One of the most popular is that a Roman soldier came upon Archimedes while he was drawing diagrams in sand during the Roman siege of Syracuse during the Second Punic War. As legend has it, Archimedes, so involved in his calculations, had not noticed the commotion around him; he offended he intruder by saying, â€Å"Do not disturb my diagrams.† The soldier stabbed Archimedes through the chest, killing what historians call one the Three Greatest Mathematicians. Archimedes wrote many books containing his propositions and proofs before his death, but none were so famous as The Method Treating of Mechanical Problems, or more simply known as The Method. This work is also widely known as the Archimedes Palimpsest. ... ..., Archimedes provides a proposition as to the cause of this remarkable experiment. He sates that two solids of equal weight and equal size will, when immersed in water, will displace the same amount of liquid. He also states that the two solids will come to rest just beneath the surface of the water. Archimedes hypothesizes that any solid that is heavier than a fluid will sink to the bottom of the fluid, but will be lighter than the fluid displaced, if weighed in the fluid. Archimedes was, in conclusion, one of the greatest mathematicians of all time. Without his contributions, the branch of math known as the calculus would likely not be complete, nor would there likely be as many advances in the fields of science and mechanics as we have today. One can hardly imagine what great treasures will be unlocked in the Palimpsest, or where those discoveries might lead.

Carl’s Jr. Commercial

Fried Sexuality It is funny how you can get the attention of a man’s sexual desires through a commercial. You can’t blame a man for his behavior. It’s in our nature to be who we are as men. Specifically, the kind of men that can be tricked by a mere image of a woman, in a bikini, eating a cheese burger. The advertisements in today’s world have been altered to use women as bait to reel in men and buy the product without any hesitation. If I told you that if you go to Carl’s Jr. and purchase a cheeseburger and a gorgeous model comes with the burger, would you buy it?I sure would†¦if only it were true. Carl’s Jr. is known for having its famous juicy, charbroiled, seven hundred calorie burgers. Anytime they want to promote a new burger, they use a model dressed revealingly to present the burger. They have the model eat very slowly and take big bites out of the burger to show its ingredients and condiments. At the end of the commercial there is a white background and the burger falls from the sky and lands on the white ground. End of commercial. We have sort of gotten the feeling that these advertisements tend to be repetitive and very similar.It has come to my attention that these commercials were pitched by men or a man. Only a man could use a woman as his tool and present her in front of an audience of millions to show the new way of how to unveil a new product. I have seen so many Carl’s Jr. commercials to the point where I feel like they want me to buy the model, rather than the burger. Nonetheless, having the model will not solve my hunger problem but having her for the sexual desire aspect will suffice. What appealed to me was the lack of importance of the burger in the beginning of the commercial.The commercial starts with the beautiful model at the beach. She is lying on the beach on a towel. The sun is so bright it makes her skin glow and come to life. A breeze flows through the air and has her hair dan cing with the wind. Her face so delicate and lovely. As she eats the burger, sauce drips on to her skin. As if the men weren’t aroused already, she wipes the sauce with her finger and licks it off. The newest burger from Carl’s Jr. is the Memphis BBQ Pulled Pork burger. The commercial, dare I say it, is hot.You find yourself at an annual cook-off in Memphis, Tennessee and come across stands selling food, beer, etc. This one particular stand has these two gorgeous girls flipping patties and teasing each other. They give each other menacing looks. You can feel the sexual tension rising. The camera is behind the girls and you can clearly see that they are wearing, what appeared to be, shorts. These shorts allow you to see the girls’ rear ends hanging. The heat was so unstable you can see sweat sliding down their tan, perfect bodies like children sliding down a tube at a waterpark.Remember when I said that these commercials tend to be repetitive? Well history repeat s itself because also in this commercial, one of the girls has a drop of sauce land on one of her breasts. She immediately wipes it with her finger and licks it like it was a lollipop. The table across from the girls has two men standing there, staring at them with their mouths so wide open that their jaws are touching the floor. Meanwhile, the girls have put together their burgers and are feeding each other.The men over at the other table took out their cell phones and started to take pictures, like they were teenagers recording a fight in high school. I am going out on a limb here by saying that this and many other commercials by Carl’s Jr. received generally more negative reviews than positive. Those negative reviews came from concerned and angry mothers. One mother had this to say about one of Carl’s Jr. ’s commercials: â€Å"This is absolutely the most disgusting commercial Carl's Jr has came up with so far. The women looks like she's actually getting sexu ally aroused from eating a hamburger for God sake!Not to mention she even looks as if she's fingering herself† (http://www. complaintsboard. com). Now this post received many negative comments from men and good comments from mothers. The mother goes on to say: â€Å"The FCC need's to ban this filthy commercial right off the air. There are innocent children that are being subjected to that appalling, demoralizing smut† (http://www. complaintsboard. com). Several comments to this post were very crucial and degrading. One comment said the following about the concerned mother: â€Å"Oh shut the hell up and quit your bitching.You are just pissed because she is one of the most gorgeous females walking the earth and you are probably just some fat chick who is pissed because you feel even more guilty when you go and eat at Carl's Jr every other day because you have to look at yourself in the mirror and wish you looked like her. If it bothers you that much then find a new burge r joint to fill your mouth with to gain more weight† (http://www. complaintsboard. com). I wouldn’t call that comment very â€Å"heartwarming† but what is heartwarming is the flow of endless money into your bank account after that commercial is aired in front of billions watching worldwide.I asked my mother if she remembers the burger Carl’s Jr. was advertising in the Memphis BBQ cook-off and she told me: â€Å"What? They were selling burgers? I thought they were selling prostitutes! † Well that’s my mother for you. Just another confused and possibly concerned parent. I asked my father the same question and he told me: â€Å"I got to go get that burger! † Like father, like son. Carl’s Jr. has created this new way of advertising for the same reason we have jobs. To make money and lots of it.

Early Education of Native Americans - 830 Words

Native Americans put up a good fight in defending their homelands against foreign invaders. Unfortunately, they suffered defeat and realized they would have to adapt to a new way of life. The battle for their lands was over, but the battle for their identities would just begin. However, it would not be the hardened warriors engaging in this conflict. Instead, the young Native American children would witness first-hand the American government’s solution to the Indian problem. Boarding schools were established to assimilate Native American children into white society. These boarding schools had both positive and negative impacts on the children. Education was seen as the key to saving the Indians and would be forced upon them if necessary (Calloway, 425). The adults of Native American tribes were the first target for this approach (Calloway, 425). However, the plan backfired due to many adults resisting the assimilation project (Calloway, 425). The next step was to go after easier targets; the children (Calloway, 425). It proved to be a haunting experience for the children as many were pulled out of their own mothers’ arms (Calloway, 426). Some children were already attending schools located on the reservation (Calloway, 426). The education reformers thought it was best to relocate the children to school off the reservation (Calloway, 426). They wanted to isolate the children from their Indian ways and that meant taking them away from family and culture (Calloway, 426). AtShow MoreRelatedLiberty And Education For All America, The Land Of Opportunity1531 Words   |  7 PagesLiberty and Education for All America, the land of opportunity. Many people imagine of making their dreams a reality in the country of the United States, some do succeed but for others it is out of their reach. Many people do not think of the fight for education to be an issue in America, especially since America is called â€Å"the best nation on Earth†. 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