Extra-Terrestrial Existence :: essays research papers fc

Has intelligent extra-terrestrial life visited the Earth? Have people actually seen spacecraft from another world? Have these spacecraft abducted human beings and performed experiments on them? Have these spacecraft been recovered by our goverment? Many believe this to be very true. Contrary to these beliefs, there is no physical or any evidence to prove these aliens have visited the Earth. But that does not rule out the existence of intelligent life elsewere in the Universe. There could always be life out there. But way to far away to have visited the Earth. The major reason people believe in aliens is a good reason to believe. This major reason is the sighting of a UFO. UFOs have revolutionized the way people think about aliens. The term UFO means: Unidentified Flying Object. Today the term UFO usually is reffered to an alien spacecraft. These alien â€Å"spacecraft† come in many shapes and sizes. The most common UFO has a disk or saucer shape. They move at very high speeds and appear to spin on an axis. UFO sightings vary from person to person. there have been so many reports of UFO sightings they can’t be counted. But are these sightings really alien spacecraft? The earliest sighting of a UFO is dated back to 213 B.C. Theses sighting were thought to be alien craft. Studies show that these sightings could have been a comet of a meteor. Around 742-814 A. D. "During the reign of Charlemagne, spacecraft took away some of the earth's inhabitants to show them something of the way of life of space people. These events are described in the Comte de Gabalis' Discourses.† Trench 1966. The University of Colorado conducted a UFO report. This elaborate report was lead by Edward U. Condon. Condon states, The decision to etablish this report for the Scientific Study of Unidentified Flying Objects stems from recommendations in a report dated March 1966 of an Ad Hoc Commitee of the Air Force Scientific advisory board set up under the chairmanship of Dr. Brian O’Brien to review the work of Project Blue Book. In this report Condon gives examples of some UFO reports. In 1952, so many UFO reports came in it clogged some Military communication channels. It was believed that an enemy planning a sneak attack could report a bunch of UFO reports to cause mass confusion to the Military communcations. Since 1953 many results of UFO study have been unclassified except when reasons needed to withold evidence because of classified missles or classified radar.

Indicate A Person Who Has Had A Significant Influence On You

Cholera is an infectious disease that causes severe watery diarrhea, which can lead to dehydration and even death if untreated. It is caused by eating food or drinking water contaminated with a bacterium called Vibrio cholerae. Cholera was prevalent in the U. S. in the 1800s before modern water and sewage treatment systems eliminated its spread by contaminated water. Only about 10 cases of cholera are reported each year in the U. S. and half of these are acquired abroad. Rarely, contaminated seafood has caused cholera outbreaks in the U. S.However, cholera outbreaks are still a serious problem in other parts of the world, where cholera affects an estimated 3 to 5 million people and causes more than 100,000 deaths each year. The disease is most common in places with poor sanitation, crowding, war, and famine. Common locations include parts of Africa, south Asia, and Latin America. If you are traveling to one of those areas, knowing the following cholera facts can help protect you and your family. Cholera Causes Vibrio cholerae, the bacterium that causes cholera, is usually found in food or water contaminated by feces from a person with the infection.Common sources include: Municipal water supplies Ice made from municipal water Foods and drinks sold by street vendors Vegetables grown with water containing human wastes Raw or undercooked fish and seafood caught in waters polluted with sewage When a person consumes the contaminated food or water, the bacteria release a toxin in the intestines that produces severe diarrhea. It is not likely you will catch cholera just from casual contact with an infected person. Cholera Symptoms Symptoms of cholera can begin as soon as a few hours or as long as five days after infection. Often symptoms are mild.But sometimes they are very serious. About one in 20 people infected have severe watery diarrhea accompanied by vomiting, which can quickly lead to dehydration. Although many infected people may have minimal or no symptoms, t hey can still contribute to spread of the infection. Signs and symptoms of dehydration include: Rapid heart rate Loss of skin elasticity (the ability to return to original position quickly if pinched) Dry mucous membranes, including the inside of the mouth, throat, nose, and eyelids Low blood pressure Thirst Muscle cramps If not treated, dehydration can lead to shock and death in a matter of hours.Yellow fever is caused by a virus. The yellow fever virus is a single-stranded RNA virus that belongs to the Flavivirus genus. After transmission of the virus occurs, it replicates in regional lymph nodes and subsequently spreads via the bloodstream. This widespread dissemination can affect the bone marrow, spleen, lymph nodes, kidneys, and liver, in addition to other organs. Tissue damage to the liver, for example, can lead to jaundice and disrupt the body's blood-clotting mechanism, leading to the hemorrhagic complications sometimes seen with yellow fever.Yellow fever is transmitted to h umans by the bite of infected mosquitoes. Various species of Aedes and Haemagogus mosquitoes serve as vectors and are responsible for the transmission to human and nonhuman primates, which serve as reservoirs for the disease. Three transmission cycles for yellow fever have been identified. Sylvatic (jungle) cycle: In tropical rain forests, infected monkeys pass the virus to mosquitoes that feed on them. These infected mosquitoes then bite humans who enter the rain forest for occupational (for example, loggers) or recreational activities.Intermediate (savannah) cycle: In humid or semi-humid regions of Africa, mosquitoes that breed around households and in the wild (semi-domestic mosquitoes) infect both humans and monkeys. The virus can be transmitted from monkeys to humans, or from human to human by the mosquitoes. This is the most common type of outbreak in Africa. Urban cycle: When infected humans introduce the virus into urban areas with large numbers of unvaccinated individuals, infected mosquitoes (Aedes aegypti) transmit the disease from human to human. This form of transmission can lead to large epidemics.

Magma Versus Lava How It Melts, Rises, and Evolves

In the textbook picture of the rock cycle, everything starts with molten underground rock: magma. What do we know about it? Magma and Lava Magma is a lot more than lava. Lava is the name for molten rock that has erupted onto the Earths surface - the red-hot material spilling from volcanoes. Lava is also the name for the resulting solid rock. In contrast, magma is unseen. Any rock underground that is fully or partially melted qualifies as magma. We know it exists because every igneous rock type solidified from a molten state: granite, peridotite, basalt, obsidian and all the rest. How Magma Melts Geologists call the whole process of making melts magmagenesis. This section is a very basic introduction to a complicated subject. Obviously, it takes a lot of heat to melt rocks. Earth has a lot of heat inside, some of it left over from the planets formation and some of it generated by radioactivity and other physical means. However, even though the bulk of our planet - the mantle, between the rocky crust and the iron core  - has temperatures reaching thousands of degrees, its solid rock. (We know this because it transmits earthquake waves like a solid.) Thats because high pressure counteracts high temperature. Put another way, high pressure raises the melting point. Given that situation, there are three ways to create magma: raise the temperature over the melting point, or lower the melting point by reducing the pressure (a physical mechanism) or by adding a flux (a chemical mechanism). Magma arises in all three ways - often all three at once - as the upper mantle is stirred by plate tectonics. Heat transfer: A rising body of magma - an intrusion - sends out heat to the colder rocks around it, especially as the intrusion solidifies. If those rocks are already on the verge of melting, the extra heat is all it takes. This is how rhyolitic magmas, typical of continental interiors, are often explained. Decompression melting: Where two plates are pulled apart, the mantle beneath rises into the gap. As the pressure is reduced, the rock begins to melt. Melting of this type happens, then, wherever plates are stretched apart - at divergent margins and areas of continental and back-arc extension (learn more about  divergent zones). Flux melting: Wherever water (or other volatiles like carbon dioxide or sulfur gases) can be stirred into a body of rock, the effect on melting is dramatic. This accounts for the copious volcanism near subduction zones, where descending plates carry down water, sediment, carbonaceous matter and hydrated mineral with them. The volatiles released from the sinking plate rise into the overlying plate, giving rise to the worlds volcanic arcs. The composition of a magma depends on the type of rock it melted from and how completely it melted. The first bits to melt are richest in silica (most felsic) and lowest in iron and magnesium (least mafic). So ultramafic mantle rock (peridotite) yields a mafic melt (gabbro and basalt), which forms the oceanic plates at the mid-ocean ridges. Mafic rock yields a felsic melt (andesite, rhyolite, granitoid). The greater the degree of melting, the more closely a magma resembles its source rock. How Magma Rises Once magma forms, it tries to rise. Buoyancy is the prime mover of magma because melted rock is always less dense than solid rock. Rising magma tends to remain fluid, even if its cooling because it continues to decompress. There is no guarantee that a magma will reach the surface, though. Plutonic rocks (granite, gabbro and so on) with their large mineral grains represent magmas that froze, very slowly, deep underground. We commonly picture magma as big bodies of melt, but it moves upward in slim pods and thin stringers, occupying the crust and upper mantle like water fills a sponge. We know this because seismic waves slow down in magma bodies, but do not disappear as they would in a liquid. We also know that magma is hardly ever a simple liquid. Think of it as a continuum from broth to stew. Its usually described as a mush of mineral crystals carried in a liquid, sometimes with bubbles of gas too. The crystals are usually denser than the liquid and tend to slowly settle downward, depending on the magmas stiffness (viscosity). How Magma Evolves Magmas evolve in three main ways: they change as they slowly crystallize, mix with other magmas, and melt the rocks around them. Together these mechanisms are called magmatic differentiation. Magma may stop with differentiation, settle down and solidify into a plutonic rock. Or it may enter a final phase that leads to eruption. Magma crystallizes as it cools in a fairly predictable way, as we have worked out by experiment. It helps to think of magma not as a simple melted substance, like glass or metal in a smelter, but as a hot solution of chemical elements and ions that have many options as they become mineral crystals. The first minerals to crystallize are those with mafic compositions and (generally) high melting points: olivine, pyroxene, and calcium-rich plagioclase. The liquid left behind, then, changes composition in the opposite way. The process continues with other minerals, yielding a liquid with more and more silica. There are many more details that igneous petrologists must learn in school (or read about The Bowen Reaction Series), but thats the gist of crystal fractionation.Magma can mix with an existing body of magma. What takes place then is more than simply stirring the two melts together, because crystals from one can react with the liquid from the other. The invader can energize the older magma, or they can form an emulsion with blobs of one floating in the other. But the basic principle of magma mixing is simple.When magma invades a place in the solid crust, it influences the country rock existing there. Its hot temperature and its leaking volatiles can cause portions of the country rock - usually the felsic part - to melt and enter the magma. Xenoliths - whole chunks of country rock - can enter the magma this way too. This process is called assimilation. The final phase of differentiation involves the volatiles. The water and gases that are dissolved in magma eventually start to bubble out as the magma rises nearer to the surface. Once that starts, the pace of activity in a magma rises dramatically. At this point, magma is ready for the runaway process that leads to eruption. For this part of the story, proceed to Volcanism in a Nutshell.