Loose Leaf For Explorations: Introduction To Astronomy
9th Edition
ISBN: 9781260432145
Author: Thomas T Arny, Stephen E Schneider Professor
Publisher: McGraw-Hill Education
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Chapter 17, Problem 20QFR
To determine
The meaning of dark matter, observations supporting the existence of dark matter and the types of dark matter that have been proposed.
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An astronomer observed the motions of some galaxies. Based on his observations, he made the following statements. Which one of them is most likely to be false? Take Hubble's constant to be 67 km/s/Mpc.
A. A galaxy observed to be moving away from us at a speed of 70 km/s is at a distance of about 1 Mpc from us.
B. A galaxy observed to be moving away from us at a speed of 700 km/s is at a distance of about 10 Mpc from us.
C. A galaxy observed to be moving away from us at a speed of 7000 km/s is at a distance of about 100 Mpc from us.
D. A galaxy observed to be moving away from us at a speed of 70000 km/s is at a distance of about 1 Gpc from us.
Is the answer D? Thank you!
What is “dark energy”?
What is “dark matter”? Why do some scientists think it is everywhere, while Houston thinks it is a lazy crock of….?
1. The current (critical) density of our universe is pe = 10-26kg/m³. Assume the universe is
filled with cubes with equal size that each contain one person of m = 100kg. What would
the length of the side of such a cube have to be in order to give the correct critical density?
How many hydrogen atoms would you need in a box of 1 m³ to reach the critical density?
The matter we know, which consists mostly of hydrogen, constitutes only 4.8% of the current
critical energy density of our universe. So how many hydrogen atoms are actually in a box
of 1 m3 in our universe? Deep space is very empty and a much better vacuum than we can
obtain on earth in a laboratory.
Chapter 17 Solutions
Loose Leaf For Explorations: Introduction To Astronomy
Ch. 17 - Prob. 1QFRCh. 17 - Prob. 2QFRCh. 17 - Prob. 3QFRCh. 17 - Prob. 4QFRCh. 17 - (17.3) Why are galaxy collisions of interest?Ch. 17 - Prob. 6QFRCh. 17 - Prob. 7QFRCh. 17 - Prob. 8QFRCh. 17 - Prob. 9QFRCh. 17 - Prob. 10QFR
Ch. 17 - Prob. 11QFRCh. 17 - Prob. 12QFRCh. 17 - Prob. 13QFRCh. 17 - Prob. 14QFRCh. 17 - Prob. 15QFRCh. 17 - Prob. 16QFRCh. 17 - Prob. 17QFRCh. 17 - Prob. 18QFRCh. 17 - Prob. 19QFRCh. 17 - Prob. 20QFRCh. 17 - Prob. 21QFRCh. 17 - Prob. 22QFRCh. 17 - Prob. 1TQCh. 17 - Prob. 2TQCh. 17 - Prob. 3TQCh. 17 - Prob. 4TQCh. 17 - Prob. 5TQCh. 17 - Prob. 6TQCh. 17 - Prob. 1PCh. 17 - Prob. 2PCh. 17 - Prob. 3PCh. 17 - Prob. 4PCh. 17 - Prob. 5PCh. 17 - Prob. 6PCh. 17 - Prob. 7PCh. 17 - Prob. 8PCh. 17 - Prob. 9PCh. 17 - Prob. 10PCh. 17 - Prob. 1TYCh. 17 - Prob. 2TYCh. 17 - Prob. 3TYCh. 17 - Prob. 4TYCh. 17 - Prob. 5TYCh. 17 - Prob. 6TYCh. 17 - Prob. 7TYCh. 17 - Prob. 8TYCh. 17 - Prob. 9TYCh. 17 - Prob. 10TY
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