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 13P
How many galaxies like our own would it take if they were placed edge-to-edge to reach the nearest galaxy? (Hint: See Problems 11 and 12.)
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Suppose you want to observe every galaxy within some distance. Your enterprising assistant says that instead you can observe every galaxy within double the original distance. What is the ratio of the number of galaxies you can now observe as opposed to before?
Approximate values of length (in meters)
107
Diameter of Earth
1011
Distance from Earth to Sun
1016
Distance traveled by light in one year
1021
Diameter of the Milky Way Galaxy
1022
Distance from Earth to the nearest galaxy
1025 Distance from Earth to the edge of the known universe
I asked the following question and was given the attached solution:
Suppose that the universe were full of spherical objects, each of mass m and radius r . If the objects were distributed uniformly throughout the universe, what number density (#/m3) of spherical objects would be required to make the density equal to the critical density of our Universe?
Values:
m = 4 kg
r = 0.0407 m
Answer must be in scientific notation and include zero decimal places (1 sig fig --- e.g., 1234 should be written as 1*10^3)
I don't follow the work and I got the wrong answer, so please help and show your work as I do not follow along easily
thanks
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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