Shape of Earth Coursework (Coursework Sample)

Shape of the Earth
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Introduction
The first assumptions about the shape of the earth were initially documented in Mesopotamian mythology. It depicted the earth to be a flat disk that surrounded by a sky that was spherical and floated in the oceans. However, that school of thought was dispelled by early Greek philosophy and confirmed by Hellenistic astronomy which established the shape of the earth to be spherical. However, it is important to note that the shape of the earth does not reflect that of a perfect sphere. Its actual shape is described as to be ‘oblate spheroid’. This means that the earth is has an oblong shape that is almost spherical, though not quite one. This is due to the difference in its parameters; from the shortest diameter (from the North Pole to the South Pole) and the longest diameter (equatorial diameter) measure 12,714 km and 12,756 km hence the slight difference accounts for its oblate spheroid shape.
Evidence why the earth is spherical in shape
1. Photographic evidence
Pictures that have been taken from space argue in favor of the earth’s shape being ‘spherical’ and not flat. When viewed at any point in space, the earth’s shape is appears spherical in nature. As earlier stated, it is not a perfect sphere as it is flattened at the poles. Despite the vantage point in which the photos are taken from space, the earth appears to be spherical.
2. Changing positions of the stars
Evidence of the earth’ spherical shape is supported by the accurate measurements of the positions of the stars. As one moves across the earth, the position of the sun and other stars appear to change. If the earth was flat, the positions would appear the same. A good example is the position of Polaris, the Northern Star.
3. Gravity
The pull of objects to the center of the earth changes as it moves from center of the earth. The further an object moves, the less it weighs and vice versa. If the earth was flat, they would weigh the same at any point. However, this is not the case as objects weigh less at the equator and more at the poles given that the earth’s diameter is least and they weigh less at the equator where the earth’s diameter’s is greatest.
4. Other planets
Other planets in the solar system are spherical in shape. Therefore, the earth, which is also a planet, is considered to be of the same nature.
5. Circumnavigation and daytime gains and losses
If you travel from one point and goes around the earth, you will end up at your point of origin. This is proof that the earth is spherical. Moreover, circumnavigation of the earth results in the gain or loss of a day, relative those who did not travel.
6. Time zones
If the earth were flat, then all places would be having the same day and night time. However, due to the earth’s spherical shape, places have different time zones as the earth rotates around the sun. In addition, the length of the day varies the further one goes from the equator.
7. Eclipses
Another proof of the earth spherical shape is exhibited during the lunar eclipse. The earth casts a circular shadow on the moon. This would not have been possible if the earth was flat.
8. Artificial satellites
Artificial satellites that circumnavigate the earth have proven that the earth is spherical in nature.
Explain the goals of NASA’s missions to Mars and highlight any preliminary findings with appropriate illustrations
1. To determine whether Life ever arose on Mars
Water is essential for life. Therefore, it is important to discover whether or not the Martian environment is conducive for any forms of life by exploring the history of water on the planet. NASA's Mars Exploration Rover managed to gather data and a few findings can be made. The rover discovered that there was an indication of water soaked place on the Meridiani plains where large deposits of hematite, which is formed in the presence of water were found from the rocks and soil samples (Jet Propulsion Laboratory: California Institute of technology).
2. To characterize the Climate of Mars
As a planet, Mars is considered to have a very low atmospheric pressure as well as being too cold for habitation as liquid water is yet to be discovered. Earlier missions by NASA’a Sojourner, Pathfinder lander and Global Surveyor Orbiter indicate that the planet was once wetter while some scientists think it was warmer. Others speculate that occasional volcanic activity may melt the frozen polar ice. However, the modern Mars is covered with streaks of materials and sand dunes deposited by wind. Evidence of water in the past has been supported by the fact that the surface has been wet at times (Jet Propulsio...