Essay on The Universe
The Universe Term Papers
While the free essays can give you inspiration for writing, they cannot be used 'as is' because they will not meet your assignment's requirements. If you are in a time crunch, then you need a custom written term paper on your subject (the universe)
Here you can hire an independent writer/researcher to custom write you an authentic essay to your specifications that will pass any plagiarism test (e.g. Turnitin). Waste no more time!
Student's Name: Paul Blanton
The Universe
Summary : 100% 5 correct out of the 5 marked for grading
1. What is the composition of the Sun's surface?
Your Answer: 94% hydrogen, 5.9% helium, .1% other
The Sun's surface is called the photosphere and it is made up (by number of atoms) of about 94.0% hydrogen and 5.9% helium, with only traces of the heavier elements making up the other 0.1%
2. State the two primary motions that the Sun is undergoing.
Your Answer: It rotates on its axis, and it revolves around the center of the Milky Way Galaxy.
The Sun's equatorial region rotates about its own axis every 25 Earth days, while the polar regions take slightly longer. The Sun also revolves about the center of the Milky Way Galaxy with a period of one revolution every 250 million years.
3. What are sunspots.
Your Answer:asdf
Sunspots are patches on the surface of the Sun that are cooler than the surrounding region by several hundred degrees. They, therefore, appear as dark spots on the Sun's hot surface, hence their name. They usually last for several days and sometimes up to several weeks. Sunspots are thousands of miles in width and are related to changes in the Sun's magnetic field. Sunspots occur in greater numbers on the Sun's surface in a regular 11-year cycle.
4. What is the celestial sphere?
Your Answer: Imaginary transparent that surrounds the Earth which planets can be positioned.
The celestial sphere is a huge, imaginary, transparent sphere that completely surrounds Earth and on which the observable celestial objects that appear as part of the night sky can be positioned. This sphere undergoes an apparent rotation, as seen by an observer located on Earth's surface, such that it accounts for the motions of all of the "fixed stars." The Sun, Moon, and planets move across the surface of the celestial sphere with respect to the fixed stars along a general path called the ecliptic. An observer on Earth's surface can only see half the celestial sphere at one time. It appears as a large, transparent, overhead dome moving westward, but this apparent motion is really caused by the motion of Earth as it rotates eastward.
5. What is the zodiac?
Your Answer: a section which follows the path of the sun on the celestial sphere.
The zodiac is a section extending around the celestial sphere 8. above and 8. below the apparent path of the Sun across the sphere. This path is called the ecliptic. The zodiac is divided into 12 nearly equal sections, each of which is about 30. wide and 16. high. Each section has its apex at the Sun and extends outward to infinity. The names of these sections, often called the signs of the zodiac, are taken from the predominant constellation that can be seen in that region of the sky.
6. Define the unit of length called the parsec.
Your Answer: Distance to a star when the star s parallel is one second of arc.
One parsec is the distance to a star when that star exhibits a parallax angle of one second of arc. One parsec is equal to 3.26 light-years or 206,265 astronomical units. (See Figure 18.8 in the textbook for details on parallax measurement and the distance unit, the parsec.)
7. What is meant by the absolute magnitude of a star?
Your Answer: The apparent magnitude of a star if it were moved to ten parsecs from Earth.
The absolute magnitude is defined as the apparent magnitude that a star would have if it were moved (in our imagination) to a location exactly 10 parsecs from Earth. Thus the absolute magnitude can be used to compare the true brightnesses of the stars. When we observe stars in their actual locations from Earth, their distances from us are primary factors in determining how bright they appear to be. The actual brightness that we observe when viewing a star from Earth is called the apparent magnitude of that star.
8. What is a Hertzsprung-Russell diagram?
Your Answer: A plot of absolute magnitudes of stars.
A Hertzsprung-Russell, or H-R diagram is a plot of the absolute magnitudes of stars as a function of their surface temperatures. On an H-R diagram, different types of stars, such as main sequence stars, red giants, and white dwarfs, are located in well defined areas, which makes the diagram useful in assigning characteristics to stars for which we know only the absolute magnitude and/or surface temperature.
9. What are Cepheid variables?
Your Answer: Stars in which their absolute magnitude varies.
Cepheid variables are stars that exhibit a periodic variation in their absolute magnitude or brightnesses. A linear relationship has been discovered between the length of these periods and the absolute magnitudes of the stars, so we need only measure the time between brightness maxima to estimate the absolute magnitude of a given star. Then using the inverse square law of intensity we can calculate the distance to this star. This is one of the best methods astronomers have for finding the distance to faraway stars and the galaxies that they inhabit.
10. How are galaxies classified?
Your Answer: By their appearance to an observer on Earth.
Galaxies are classified by their appearance to an observer on Earth. This determination is usually made after studying photographs of the galaxies taken by our largest telescopes.
11. What are the three main classifications of galaxies?
Your Answer: Elliptical, spiral, and irregular.
Galaxies are classified as either elliptical or spiral, depending on their appearance as seen from Earth. Any galaxies that do not fit into these two main categories are simply called irregular galaxies.
12. Which type of galaxy is most abundant?
Your Answer: Most are spiral galaxies
Of the brighter galaxies observed from Earth, over 75% are of the spiral type, but in any given volume of space there are more elliptical galaxies than spirals. This is the case because elliptical galaxies are made up of older stars that are generally dimmer than the young stars that predominate in spiral galaxies. This makes the spiral galaxies easier to see at large distances. The third type, irregular galaxies, appear to make up only about 3% of all known galaxies.
13. What are the principal phases in the life cycle of a star?
Your Answer: Begin as a cloud of gas called main sequence stars, then depending on their size, they enter white dwarf, neutron, or black hole stage.
Stars begin their lives as large clouds of gas and dust that collect under the pull of gravity into main sequence stars, during which phase they produce energy from the fusion of hydrogen in their cores. When the hydrogen becomes depleted, they evolve into their red giant phase where helium is the main core fuel. When the helium in the core also gives out, stars end their lives in one of three final states, depending on their masses at this point in their lives. These final states are white dwarf stars, neutron stars, and black holes.
14. What are the physical dimensions of the Milky Way Galaxy?
Your Answer: 100,000 light-years in diameter and 2,000 light-years thick.
The Milky Way is 100,000 light-years in diameter and 2,000 light-years in thickness in the region where our solar system is found. There is also a much thicker central bulge (10,000 ly) surrounding its center of rotation. The Milky Way contains about 100 billion individual stars.
15. What is a black hole?
Your Answer: a collapsed star with strong gravitational pull.
A black hole is believed to be a collapsed star with a gravitational field so strong that nothing, not even light, can escape from it. Black holes are the final stage in the life cycles of the most massive stars.
16. What are Seyfert galaxies?
Your Answer: They have bright centers and tend to give off high levels of radio emissions.
Seyfert galaxies are galaxies that exhibit very bright centers and whose spectra show broad emission lines. They tend to give off large amounts of radio emissions from their cores, but they look like normal spiral galaxies through an optical telescope.
17. What are superclusters?
Your Answer: Large clusters made of individual clusters of galaxies.
Superclusters are huge clusters made up of many individual clusters of galaxies lumped together. They vary from 50 to 300 million ly in diameter and contain masses that are estimated to be greater than 1015 solar masses.
18. What is the Hubble constant?
Your Answer: Constant of proportionality in Hubble s law which relates to galaxies distance from Earth.
The Hubble constant is the constant of proportionality (H) in Hubble's law (v = H d), which relates the speed of recession (v) for remote galaxies to their distances from Earth (d). The...
MLA Style
. EssayMania.com. Retrieved on 11 Feb, 2012 from
<http://essaymania.com/143548/the-universe>
More College Papers
Sonnet 130
My mistress' eyes are nothing like the sun;Coral is far more red than her lips' red;If snow be white, why then her breasts are dun;If hairs be wires, black wires grow on her head.I have seen roses damask'd, red and white,But no such roses see I in her cheeks;And in some perfumes is there more deligh
Clean Up On Aisle Four
Clean Up on Aisle Four
As her son reaches out of the cart for anything he can get his hands on, the young woman tries to decide in what section of the store is the best place for her to begin her venture. Located in the heart of Green Hills, the red-schemed H.G. Hills Food Store has been helping fa
untitled
Words = 1740
A Day in the Life of Ivan Denisovich
In "A Day in the Life of Ivan Denisovich", the author tells the tale of Ivan Denisovich Shukov, a prisoner in a Russian work camp during the reign of Stalin who had been arrested for high treason. Solzhenitsyn introduces the reader to the sched