Essay: Earth Science Astronomy

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Earth Science / Astronomy

Ptolemy focused on a series of earlier ideas when he devised his theory regarding the geocentric movement of the planets. The theory emphasized the fact that the Earth was stationary and at the center of the universe. All the objects in the universe were believed by Ptolemy to revolve around earth. The Greek astronomer observed that the celestial bodies appear every day in the same place they did a day before and that the Earth appeared to be at rest because of its presumed stability. This theory contributed to the belief that the Earth was spherical, not flat as most people formerly believed.

The Earth performs a complete revolution every twenty-four hours, relative to the sun. Every year the Earth revolves around the sun, this motion lasting for approximately three hundred and sixty five days. The Earth performs a complete cycle of precession once in approximately 26000 years, with the current angle between its rotational axis and the plane to its trajectory being 23.44 degrees.

Q3. Nicolaus Copernicus is responsible for devising a reasonable heliocentric theory. Tycho Brahe was a Danish astronomer who devoted his life to studying astronomy and the movement of the planets, bringing large contributions to the field of astronomy and providing his assistant, Johannes Kepler, with information which the latter used in developing the laws of planetary motion. Kepler's studies were essential in assisting Sir Isaac Newton in devising the theory of universal gravitation. Galileo Galilei lived contemporary to Kepler, with the latter mentioning a series of the former's achievements for astronomy, namely the confirmation of Venus's phases and the finding of Jupiter's four largest satellites. Galilei is also responsible for perfecting the telescope.

Q4. There are eight planets in the solar system, Mercury, Venus, Earth and Mars are referred to as "terrestrial planets" while Jupiter, Saturn, Uranus and Neptune are called "gas giants." The terrestrial planets are mainly composed out of rock and metal whereas the gas giants are principally made out of water, ammonia, and methane. The terrestrial planets are much smaller than the gas giants. There are also other planets in the solar system, with Pluto, Haumea, Makemake, Eris, and the asteroid Ceres representing the system's dwarf planets, which do not comply with all the requirements necessary for a celestial object to be classified as being called a principal planet in the solar system.

Q5. Stellar parallax is the phenomenon through which one can approximate the distance to a celestial object by observing the position of an object in the universe at different times in the year, the measuring tool most often used to do this being a heliometer.

Q6. Earth only has one natural satellite, the Moon. It is only surpassed by five other satellites in the solar system when considering its size, the largest satellite in the solar system in comparison to the size of the planet it revolves around, and the second densest satellite in the solar system. The lunar maria are dark areas on the planet's surface which are a result of volcanic eruptions. Their darkness is owed to the fact that they are based in plains, making them less reflective than the higher areas, which contain less iron. The moon's surface is filled with craters and most of them are a consequence of impacts. The term was first used for the depressions on the moon's surface by Galilei, who supported the theory that the moon was not a perfect sphere. Craters differ in size, with the smallest being microscopic and the largest being approximately 200 miles in diameter. Lunar maria were associated with craters, some individuals promoting the belief that the dark areas on the moon are actually craters that were filled with lava consequent to the impact. The soil on the moon is also recognized as regolith, given that it complies with the term's characteristics of being heterogeneous found on top of solid rock. Unlike the soil on earth, lunar soil does not contain moisture and air. There… [END OF PREVIEW]

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Earth Science Astronomy.  (2010, September 18).  Retrieved November 19, 2019, from

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"Earth Science Astronomy."  18 September 2010.  Web.  19 November 2019. <>.

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"Earth Science Astronomy."  September 18, 2010.  Accessed November 19, 2019.