Foundations of Astronomy (MindTap Course List)
14th Edition
ISBN: 9781337399920
Author: Michael A. Seeds, Dana Backman
Publisher: Cengage Learning
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Textbook Question
Chapter 1, Problem 4LTL
Look at Figure 1-9. Would you say that the distribution of stars is uniform in this field of view, 17 ly across? Compare with Figure 1-10, 1700 ly across. Now look at Figure 1-12; would you say that the distribution of galaxies is uniform in this field of view, 17 million ly across? Compare with Figure 1-13, 1.7 billion ly across.
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Approximate values of length (in meters)
107
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1016
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Our galaxy is approximately 100,000 light years in diameter and 2,000 light years thick through the plane of the galaxy. If we were to compare the ratio of the diameter galaxy and its thickness to the ratio of the diameter of a CD and its thickness (CD has a diameter of 12 cm and thickness of 0.6 mm), what would be the factor differentiating those ratios? Put differently, if the galaxy were scaled down to the diameter of a CD, how many times thicker or thinner would the galaxy be than the CD? (For example if it would be twice as thick, you would answer 2 and if it were twice as thin you would answer 0.5 (aka 1/2))
The Kormendy relation for ellipticals can be written as
He = 20.2+ 3.0 log R.
where R. is the half-light radius (in kpc) and 4e is the surface brightness (in magnitudes per square arc second) at R..
An elliptical galaxy obeying this relation will have a total luminosity
Lo R
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O a. n=-6/5
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T23D
Oc n= 16/5
O d. n cannot be determined with the information we have.
Chapter 1 Solutions
Foundations of Astronomy (MindTap Course List)
Ch. 1 - Prob. 1RQCh. 1 - What is the largest dimension of which you have...Ch. 1 - What is the difference between the Solar System,...Ch. 1 - What is the difference between the Moon and a...Ch. 1 - Why do astronomers now label Pluto a dwarf planet?Ch. 1 - Why are light-years more convenient than miles,...Ch. 1 - Why is it difficult to detect planets orbiting...Ch. 1 - Prob. 8RQCh. 1 - What is the difference between the Milky Way and...Ch. 1 - What are the Milky Way Galaxys spiral arms?
Ch. 1 - Prob. 11RQCh. 1 - Where are you in the Universe? If you had to give...Ch. 1 - Prob. 13RQCh. 1 - Prob. 14RQCh. 1 - Prob. 15RQCh. 1 - How do we know? How does the scientific method...Ch. 1 - The equatorial diameter of Earth is 7928 miles. If...Ch. 1 - The equatorial diameter of the Moon is 3476...Ch. 1 - One astronomical unit (AU) is about 1.5 108 km....Ch. 1 - A typical galaxy is shown on the first page of the...Ch. 1 - The time of the Cambrian explosion is listed on...Ch. 1 - Venus orbits 0.72 AU from the Sun. What is that...Ch. 1 - Light from the Sun takes 8 minutes to reach Earth....Ch. 1 - The Sun is almost 400 times farther from Earth...Ch. 1 - If the speed of light is 3.0 105 km/s, how many...Ch. 1 - Prob. 10PCh. 1 - How long does it take light to cross the diameter...Ch. 1 - The nearest galaxy to our home galaxy is about 2.5...Ch. 1 - How many galaxies like our own would it take if...Ch. 1 - Arrange the following in order of increasing size:...Ch. 1 - Prob. 2SOPCh. 1 - The Sun is roughly 100 times the diameter of...Ch. 1 - Prob. 4SOPCh. 1 - Look at the center of Figure 14. Approximately...Ch. 1 - Look at Figure 1-6. How can you tell that Mercury...Ch. 1 - Prob. 3LTLCh. 1 - Look at Figure 1-9. Would you say that the...Ch. 1 - Of the objects listed here, which would be...Ch. 1 - Prob. 6LTL
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