History of Astronomy Outline

History of Astronomy Outline University of Phoenix Astronomy SCI 151 Norm Stradleigh January 17, 2013  History of Astronomy Outline Chapter 1: Our Place in the Universe Geocentric Universe means the Earth is centered. There is an assumption that life exists within an Earth-centered universe. The Sun, planets, and Moon move around the sky in a circular motion daily. On its axis, as the Earth orbits the Sun, its rotation feels motionless to living beings. The limit to which the Earth can be studied is referred to as the observable universe. The universe is a clock that tells a time-based story revealing information about Earths’ past and future. There is no way to look beyond 14-billion light-years marking the margin of what is likely observable. The observable universe is made-up of millions of galaxies and more stars than there are grains of sand on every beach on Earth. The solar system is located midway from the galactic center. The genesis of the solar system was more than four billion years ago and was initially made-up of hydrogen and helium but later merged into more intense components generated by stars. Astronomer Carl Sagan’s reference to “Star stuff” is based on the principle that stars that lived and died prior to the existence of the Sun are responsible for the creation of Earth. Research reveals the Earth is primarily made of carbon, nitrogen, oxygen, and iron. Light is the gateway to information within the complexity of the universe. Researchers discovered light from stars travel at a slower rate and therefore the starlight’s distance is measured in units, which are referred to as light-years. The speed of light is approximately 300,000 kilometers per second. At this speed, light can travel around the entire Earth eight times in one second. Light traveling from the Sun takes eight minutes to reach Earth and the light traveling from the Moon takes one second to reach Earth. Stars and planets evolve from a massive cloud called Orion Nebula, which is located, several light-years from Earth. Many galaxies exist within groups in which those with more than 12 elements are referred to as clusters and then there are local groups that make up a tiny portion of the universe. The Milky Way contains more than 100 billion stars and is one of the largest of 40 galaxies in the “local group.” Studies indicate galaxies once closely aligned began to expand, which led astronomers to predict the big bang. Sirius is the brightest night star and is approximately eight light-years in distance meaning it takes eight years to reach Earth. Because Sirius is eight light-years away, the state in which man can see Sirius is eight years in the past. Chapter 2: Discovering the Universe for Yourself What are constellations and how did they come about? Constellations derived from the names of patterns used to described the sky by the various cultures of people Astronomers define constellation as an area of the sky with distinct boundaries. The familiarity of the stars patterns enables man to locate the constellations. Each region of the sky is directly correlated with some constellation. Evidence indicates that Earth falls within the center of the celestial sphere. The celestial sphere enables man to landmark the sky from Earth. The celestial sphere can be identify by four special points The north sphere is the point above the North Pole The south sphere is the point above the South Pole The equator makes a circular rotation around the celestial sphere The ecliptic is the direction the Sun takes as it rotates annually around the celestial sphere and crosses the equator. The images in the sky appear to be different based on the location from which an individual is viewing the sky from Earth. Stars are present within the sky around the clock, which means that even during the daylight hours the stars are out. The Sun being the brightest star during the day is so bright that it appears to be the only star in the sky to the naked eye however; a telescope allows man to confirm that stars are indeed present in the sky during the day. Tales of the North Star being the brightest is a myth as others near the North Pole shine just as bright if not brighter. Earth’s orbit helps to determine the four seasons and each season is dependent upon the direction of the hemisphere in reference to the Sun. Phases of the moon are seen because of the Moons relative position to the Sun as the Sun orbits the Earth. A portion of the Moon is exposed by the Sun at all times. The extent of what is visible to man depends on the Moons orbital position. The phase of the Moon is relative to the time the Moon rises, hits its highest level in the sky, and sets. Planetary motion was very hard to explain because of ancient assumptions that the Earth is at the center of the universe Traditionally planets move in an eastern direction, which is relative to the stars over a period of one year. There are times in which the stars direction moves in reverse, which occurs when Earth is passed by or passes by another planet. This change in course is known as the apparent retrograde motion. Ancient Greeks rejected the explanation of planetary motion. The inability for the Greeks to discover stellar parallax is responsible for their rejection. Greeks found it implausible that stars were so distant making parallax hidden to the naked eye however; evidence proves this is indeed the case. Chapter 3: The Science of Astronomy A common misconception is that scientists think differently from everyday people. Thinking scientifically is a normal part of the human thought process. Paying attention to detail, testing theories, and ensuring the validity and reliability of information are ways in which humans think scientifically. Scientific thought is heavily reliant on trial and error. Ancient cultures were vigilant in their decision-making based on an innate inquisitiveness as well as the part astronomy played in their lives. Prior to clocks, the only method for telling time was simply the sky; otherwise known as astronomical observations. The Sun, Moon, and the stars were critical elements for those who relied heavily on agriculture to gauge the seasons and time. Today measurements of time are based on ancient studies. The foundation of modern science can be traced back to Greek examples. The Greeks are responsible for creating examples of life and highlighting the significance of said examples to correspond with studies of nature. The Greeks’ definition of planetary motion is that the planets rotate around a small circle in which the inner portion of the circle moves around the Earth on a bigger circle. Constantinople’s fall was responsible for the migration of scholars to Western Europe where their experiences were instrumental to the Renaissance. “One reason science is difficult to define is that not all science works in the same way” (Bennett, Donahue, Voit, & Schneider, 2010, p. 74). Generally, science is illustrated through the process of acquiring reliable evidence-based facts about the universe. Today, three distinct trademarks otherwise known as hallmarks of science traditionally distinguish science. Modern science examines clues from the past based on facts to explain unfolding occurrences. The advancement of science takes place by testing natural theories and simplistically explaining findings. Science must be tested and evidence-based Scientific theory is factual-based explanations of scientific studies. Astrology and Astronomy are terms similar in sound but have very distinct meanings. Astrology is a belief that the location of the stars and planets when a person is born has an effect on his or her character. Astronomy is the study of anything that can be observed in the universe. In ancient history, the two were used interchangeably. Astrology played a significant role in the ancient advancement of astronomy. Today, scientific evidence indicates that astrology is not infallible. Chapter 4: Making Sense of the Universe When one thinks of motion typically, the first thing that comes to mind is movement. Movement consists of speed, velocity, and acceleration. An objects movement can measure speed, velocity is the same as speed but for a specified direction, and acceleration is a shift in speed and velocity. Together these three components generate what is known as momentum, which is mass multiplied by the direction of speed. Mass is confused with weight at times however; the difference is that mass remains the same regardless to its location, whereas weight changes based on the amount of gravity present. Newton changed man’s perception of Earth through his teaching of the potential to acquire knowledge about the Earth by examining the physical laws of the universe. Newton later went on to define three laws of motion. Objects maintain their speed and direction because of the lack of force. When force is present, it creates a shift in momentum, which influences speed and direction. For every action there is an equivalent action or reaction; simply put for every cause there is an effect Planets continually rotate and orbit the Sun because there is not enough angular resistance of momentum with anything else in their path. An object receives energy from another object when energy is exchanged at the point in which the objects paths cross. Energy consists of three components: Kinetic Radiative Potential Newton’s law of gravity simply means that objects tend to move in a downward motion. Gravity and energy define the meaning of orbits. Gravity regulates the path an object will take however; an object’s path will not change without a gain or loss of “orbital energy.” Orbital energy is defined as the total of” kinetic and gravitational potential energies.” A tidal force is responsible for pushing Earth near and apart from the Moon daily. The tidal force can also cause resistance, which reduces the speed of Earth’s cycle. References Bennett, J. O., Donahue, M., Voit, M., & Schneider, N. O. (2010). Discovering the Universe for Yourself. In The Cosmic Perspective (6th ed., pp. 26-54). Boston, MA: Addison Wesley. Bennett, J. O., Donahue, M., Voit, M., & Schneider, N. O. (2010). Making Sense of the Universe. In The Cosmic Perspective (6th ed., pp. 87-113). Boston, MA: Addison Wesley. Bennett, J. O., Donahue, M., Voit, M., & Schneider, N. O. (2010). Our Place in the Universe. In The Cosmic Perspective (6th ed., pp. 1-25). Boston, MA: Addison Wesley. Bennett, J. O., Donahue, M., Voit, M., & Schneider, N. O. (2010). The Science of Astronomy. In The Cosmic Perspective (6th ed., pp. 55-86). Boston, MA: Addison Wesley. Running head: HISTORY OF ASTRONOMY OUTLINE 1 HISTORY OF ASTRONOMY OUTLINE 2 HISTORY OF ASTRONOMY OUTLINE ?