University of Phoenix Material

Basics of Astronomy Outline

Amanda Taddei

8-27-2012

Complete the outline based on the readings for this week: Ch. 1–4 of The Cosmic Perspective. Use complete sentences for all sub points listed. The following is an example of a completed outline:

1. Our place in the universe
a. The modern view of the universe
1) What is our Sun and what is its role in the solar system?
a) Our sun is a hot ball of glowing gases that is at the heart of our solar system.
b) Our suns role is to give out energy and heat. This energy and heat allows for there to be life on earth. However, even though our sun is unique and life giving there are billions of stars that are just like it in the Milky Way galaxy. (Solar System Exploration, 2012)
2) What is our Milky Way galaxy and the sun’s position in it?
a) The Milky Way galaxy is a spiral galaxy that has arms that extend out from the center like a pinwheel. Our galaxy is one of about 100 billion visible universes. (Solar System Exploration, 2012)
b) The sun’s posistion in the galaxy is in the Orions arm of the Mily Way. However, because of how our planets are set up in our system there is life on Earth. The Sun has an almost circular orbit. The sun is just the right distance from the center of our galaxy to promote life. The planets and our sun are just the right distance apart for one of our planets, Earth, to have higher intelegance life on it.
3) What is the Big Bang and what does it say about the age of the universe?
a) Scientist says that the Big Bang is what created our universe. Edwin Hubble was the first, in 1929, to discover that the Universe was expanding an great speeds. Now Hubble discovered that planets and galaxies that were outside our own are moving away from use and that their speeds were proportional to their distances from us. It was then deduced that there had to be a point in time that a single violent event happened to create the universe. This was later named “The Big Bang.” (Solar System Exploration, 2012)
b) This means that the age of the universe can be traced back to a single point in time just like anything else that we are intelegently aware of. Everything has an exapt point of conception and can be deduced to have an exact age.
4) What is meant by the phase “looking out in the universe is looking back in time?”
a) This phrase means that when we look into the heavens and observe the lights from distant stars we are looking back in time. This could mean that we are looking back several thousand years. Because light can only travel at the speed of light when we see it in the night sky we are looking at ‘old’ light that came from a star in a distant galaxy. If we trace this light back to its source we are esentally tracing the light back to its birth and or its planet. Sometimes when light is being traced back it comes to an end without its origin planet ever being seen because it died thousands of years ago.
b. Where are we in the universe?
1) What is Earth’s place in the solar system?
a) The earth is placed in the solar system as the third planet from the sun. Its orbit is around the sun just like the other eight (8) planets in the solar system do. However, earth is the only planet in this solar system that is the exact distance from the sun and has the correct off kilter rotation that life is able to prosper upon it.
2) How close are the nearest stars to the Sun as compared to the distance between the Sun and the Earth?
a) There are 8 stars that are nearest the sun in the solar system and they are as follows closest to farthest way: Mercury, Venus, Earth, Jupiter, Saturn, Uranus, and Neptune. Then you have the dwarf planets starting with Pluto , then you have Haumea, Makemake, and Eris. The four planets that are closest to the sun are as follows:
1) Mercury at .4 AU. (Solar System Exploration, 2012)
2) Venus at .7 AU. (Solar System Exploration, 2012)
3) Earth at 1 AU and the only planet at the right distance to promote life. (Solar System Exploration, 2012)
4) Mars is at 1.5 AU which is just .5 AU to far from the sun to sustain life. (Solar System Exploration, 2012)
3) How large is our Milky Way galaxy?
a) The Milky Way galaxy is a large spinning disk of stars. It is about 100,000 light years across. However, the galaxy is only about 2,000 light years thick. At the edge of the Orion arm is where the sun of the Milky Way galaxy is located.
4) How many stars are estimated to exist in our galaxy?
a) There are about 200 billion stars in the Milky Way Galaxy. Most of these are located in the central disk of the galaxy where stars are formed.
5) How old is the earth compared to the universe itself?
a) The Milky Way galaxy is estimated by astronomers to be approximately 14.5 billion years old . The Earth is estimated to be about 4.55 billion years old that is an almost 10 billion year difference. Through cooperative investigation this information was collected all over the world.
c. Motion in the universe
1) How fast does the Earth move around the Sun? Compare that to fast things in day-to-day life.
a) The earth goes around the sun at about 67,000 miles per hour. Let’s compare this to normal day to day that is manmade.
1) The Bullet Train travels at a top speed of 262 mile per hour according to China in 2010.
2) The Voyager 1 goes 3.602 AU per year or 10,604.3661 miles per hour.
2) How is our Sun moving in the galaxy?
a) The sun is about 26,000 light years from the center of the galaxy and is half way out on one of the curving arms called Orion. The Sun and the planets associated with it take about 255 million years to revolve around the galactic center. This time is called sometimes a galactic year. It has been estimated that the galaxies sun has completed about 20 rotations since the solar system was created. (Chan, 2001)
3) How are the galaxies around the Milky Way galaxy moving from our point of view?
a) The galaxies that are in the Milky Way are moving in our point of view in an oval pattern. Because of the Earth at our feet we are not able to see in a circular manner so we can only assume that the orbits of other galaxies are similar to our own. There are pictures that have been taken over time that we can see and estimate that the Milky Way galaxy is moving in a circular pattern but because it is actually shaped like an oval it is rotating in that manner or pattern.
2. The sky and the science of astronomy
a. Explain the significance of the celestial sphere.
1) Euclidean space or straight lines and planes is how humans perceive things. Now s[pace is very large and the mind draws it in as a sphere so that it can comprehend it better. So using a spherical coordinate system is the best way for mapping the sky so that the human mind can comprehend how vast it really is.
2) What important directions and coordinate systems help you find your way around the sky?
a) The important directions and coordinate systems that help a person to find his or her way around the sky are that we use a projection of earth’s reference points onto the sky. These are the North Pole and the equator. Standing on the earth’s surface a hemisphere is marks with compass points on the horizon and the circle that would pass through the south point and the north point and the point that is directly over head which is also known as the zenith and is also called the meridian. (Celestial Sphere:, 2012)
b) This kind of system allows a person to be able to indicate any potion in the sky using two reference points and the time from the meridian along with the angle from the horizon. However, the earth rotates so the coordinates will change after a few minutes of standing in the same place. (Celestial Sphere:, 2012)
3) Why are there different brightness of stars and how do we describe their brightness as compared to one another?
a) Each star is a different distance away from the earth so the brightness of the stars are different. This can be described by how fast the light travels and what may be blocking the light from reaching completely to earth. If a star is farther away from earth then the light has to travel a longer distance and it will be dimmer by the time it reaches earth.
4) What are constellations?
a) Constellations are stars that are grouped together and make patterns in the sky they are also the brightest stars in the sky and are used to navigate over long distances. They are also used to tell what time of year it is and when a person is at sea where that person is relative to what constellation is in the sky at night.
5) What is Polaris and what is its significance in the sky?
a) Polaris is the Alpha Ursae Minoris and is not a seasonal star. It is always in the northern nighttime sky. Polaris is also the North Star and marks the north celestial pole. It is a navigator’s benchmark. (Kaler., 2012)
6) Why does the Moon change its phase, how does it move and how do these combine to create eclipses?
a) The moon changes phase because it orbits around the earth about every 29 and ½ days. It is lit by the sun but only half at all times. As the moon orbits around the earth it is rotating on its own axis so we see more and more of the sun lit side of the moon. This is what makes the phases of the moon that we see. (Moon Phases, 2012)
b. What is the science of astronomy?
1) It is a branch of physics that studies celestial bodies and the universe as a whole. Astrophysics is a type of astronomy that is more about the study of physics in space such and the laws and forces that govern objects and particles moving through space. (opensite, 2012).
c. What is the scientific method and how does it relate to the science of astronomy?
1) The scientific method is a systematic approach in the researching of questions and problems that uses objective and accurate observation. This is done through a collection and analyses if data and direct experimentation rather than with a replication of these procedures. . (John Wiley & Sons, 2000-2012)
d. Who was Aristotle and what was his relationship to the science of astronomy?
1) A Greek philosopher is what Aristotle is. He was a student of Plato and the teacher of Alexander the Great. Aristotle’s connection with astronomy is through his works in physics and metaphysics.
e. What was the Copernican revolution?
1) Immanuel Kant’s philosophy is the Copernican Revolution. In Kant’s novelty the Copernican revolution was hugely important. Kant synthesized rationalism and empiricism and he left no discussion possible when the role of human minds in constructing reality and knowledge. (LaFave, 2012)
f. What observations did Galileo make that proved that planets go around the sun?
1) Galileo Galilei (1564-1642) was considered a pivotal figure in the development of astronomy that we know today. Because of his work not only in astronomy but his work also in physics. Galileo proved that the Copernican hypothesis was correct by his observations. He laid the foundations that helped give a correct understanding of the movement of objects on the surface of earth and of gravity (Galileo: the Telescope & the Laws of Dynamics , 2012).
2) What Galileo observed was that there were four points of light that changed their positions with time around the planet Jupiter. Galileo concluded that these were objects that orbited Jupiter. These objects were the four brightest moons that orbited Jupiter. They are commonly called Galilean moons now but Galileo himself called them the Medicea Siderea or the “Medician Stars.” These observations proved that when a planet had objects orbiting it they were not left behind so therefore the Earth did orbit around the sun. (Galileo: the Telescope & the Laws of Dynamics , 2012)
g. What laws tell us how the planets move around the star?
1) The laws that tell us how stars move are called Kepler’s laws these are as follows:
a) The obit of every planet is an ellipse with the Sun at one of the two foci.
b) A line joining a planet and the sun sweeps out equal areas during equal intervals of time
c) The square of the orbital period of a planet is directly proportional to the cube of the semi-major axis of its orbit.
h. How does the Earth rotate and how does that relate to day and night or the seasons?
1) “The earth rotates on an axis which is called its rotational axis. The earth does not rotate on a straight axis of either vertical or horizontal but its axis is tipped over at about a 23.5 degree from vertical axis (The Earth's Rotation, 2012).
2) Because the earth rotates we have set hours that are lighted and set hours that are not. These are day and night time. The earth takes about 23 and ½ hours to rotate. Now this leaves about half of that for exposure to the sun and half of that is when the sun exposed side is facing away from the sun which is night time. The Earth’s rotation around the sun and its rotation on its axis are not in a perfect circle so there are some times when there are longer days and or longer nights. This also depends on where a person is on earth as to what they experience.
3) It relates to the seasons because when the earth is rotating on it axis and its orbit is close to the sun we have a hotter or summer season. When the earth is rotating on its axis away from the sun and its orbit is farther away we have more of a colder season or winter. During summer seasons we see longer days and shorter nights. During winter months we see shorter days and longer nights. Depending on where a person is we also see snow or rain in the areas that are farthest away from the sun.” (Amanda Taddei, June 2012)
i. How does the Earth revolve and how does that relate to day and night or the seasons?
1) The earth revolves around the sun. Because the earth rotates we get night and day and we get the seasons- summer, spring, winter and fall. The night and day phases happen because the earth rotates around the sun and the season happen because the earth also rotates on an axis that allowing it to spin closer to the sun and farther away from the sun.
j. What causes the seasons? Is it the tilt of the Earth’s axis or its changing distance from the Sun throughout the year?
1) The seasons, summer winter, spring and fall are created because of the earth’s rotation on its off kilter axis that brings either the top half or the bottom half of the earth closer to the sun. this is also way the seasons are opposite each other depending on where a person is on earth. For example right now in Nevada it is summer time and Nevada is located in the northern hemisphere, but if you go to the southern hemisphere it is winter time there because they are farther away from the sun.
3. Gravity, free fall, and orbits
a. What is gravity and how much weaker does it get as you get farther from the center of a body?
1) Gravity is a force that is created by the spin of a body. The faster something spins the greater the gravity or pull of that object. For example it is like spinning on a carnival ride, everyone ones which one, the faster it goes the more weight is placed on the body of the person in the ride. This is the same with a planet. The faster it goes the ‘heavier’ the gravity of the planet.
b. Are objects in orbit of the Earth still under the influence of gravity?
1) Objects that are in orbit are under the influence of the earth’s gravity but to a lesser degree than anything that is on earth. The objects that are in Earth’s orbit are pulled toward earth by its gravity but they have to be at a specific distance from earth before they will be pulled to earth’s surface.

c. An object in orbit falls around the Earth, what do planets, comets, and asteroids fall around?
1) Planets, comets, and asteroids fall around the center of the galaxy. They are influenced by whatever body in space they are near. Some come close enough to large planets or body’s and is pulled down by their gravitational pull.

Works Cited

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Austin. (2011). The Little Planet that Could - 2: The Sun’s Position in the Milky Way Galaxy. Retrieved July 11, 2012, from austin biblical creationist: http://www.austinbiblicalcreationist.org/2011/02/the-little-planet-that-could-2-the-suns-position-in-the-milky-way-galaxy.html
Celestial Sphere:. (2012, July 21). Retrieved from abyss.uoregon.edu: http://abyss.uoregon.edu/~js/ast122/lectures/lec02.html
Chan, A. (2001). Speed of the Sun. Retrieved July 11, 2012, from hypertextbook: http://hypertextbook.com/facts/2001/AngelaChan.shtml
Galileo: the Telescope & the Laws of Dynamics . (2012, July 21). Retrieved from http://csep10.phys.utk.edu/astr161/lect/history/galileo.html: http://csep10.phys.utk.edu/astr161/lect/history/galileo.html
John Wiley & Sons, I. (2000-2012, july 21). Cliffnotes.
Kaler., J. (2012, July 21). POLARIS . Retrieved from stars.astro.illinois.edu: http://stars.astro.illinois.edu/sow/polaris.html
LaFave, S. (2012, July 21). Kant: The "Copernican Revolution" in Philosophy. Retrieved from instruct.westvalley.edu: http://instruct.westvalley.edu/lafave/KANT.HTM
Math and Science Activity Center. (1999). Retrieved July 11, 2012, from edinformatics.com: http://www.edinformatics.com/math_science/solar_system/milky_way_galaxy.htm
Moon Phases. (2012, July 21). Retrieved from library.thinkquest.org: http://library.thinkquest.org/J0112188/moon_phases.htm national Aroenatics and space administration. (2012, July 21). Retrieved from NASA: http://science.nasa.gov/astrophysics/focus-areas/what-powered-the-big-bang/ opensite. (2012, july 21). Retrieved from http://open-site.org/Science/Astronomy/
Solar System Exploration: Sun. (n.d.). Retrieved July 11, 2012, from http://solarsystem.nasa.gov: http://solarsystem.nasa.gov/planets/profile.cfm?Object=Sun
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