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 16, Problem 5TQ
To determine
The explanation of density-wave theory to another person.
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1.2
1.0
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0.6
Cosmic background
data from COBE
0.4
0.2
0.0
0.5
10
Wavelength A in mm
c)
Background (CMB) undertaken by the COBE satellite. Use this diagram to estimate the
current temperature of the CMB. Based on your estimate, what would the temperature of
the CMB have been at a redshift of z = 5000?
The left hand diagram above shows the results from observations of the Cosmic Microwave
Radiated Intensity per Unit Wavelength
(16° Watts/m per mm)
Explain how the Hubble constant, H0, can be used to make an estimate for the age of the Universe. Use the value of H0 = 0.07×103 kms-1/Mpc to estimate the Universe’s age. Comment on the significance of your answer.
A galaxy's rotation curve is a measure of the orbital speed of stars as a function of distance
from the galaxy's centre. The fact that rotation curves are primarily flat at large galactocen-
tric distances (vrot(r) ~ constant) is the most common example of why astronomer's believe
dark matter exists. Let's work out why!
Assuming that each star in a given galaxy has a circular orbit, we know that the accelera-
tion due to gravity felt by each star is due to the mass enclosed within its orbital radius r and
equal to v?/r. Here, ve is the circular orbit velocity of the star. (a) Show that the expected
relationship between ve and r due to the stellar halo (p(r) xr-3.5) does not produce a flat
rotation curve. (b) Show that a p(r) ∞ r¯² density profile successfully produces a flat ro-
tation curve and must therefore be the general profile that dark matter follows in our galaxy.
Chapter 16 Solutions
Loose Leaf For Explorations: Introduction To Astronomy
Ch. 16 - Prob. 1QFRCh. 16 - How do we know our Galaxy is a flat disk?Ch. 16 - Prob. 3QFRCh. 16 - Prob. 4QFRCh. 16 - Prob. 5QFRCh. 16 - Prob. 6QFRCh. 16 - Prob. 7QFRCh. 16 - Prob. 8QFRCh. 16 - Prob. 9QFRCh. 16 - Prob. 10QFR
Ch. 16 - Prob. 11QFRCh. 16 - Prob. 12QFRCh. 16 - Prob. 13QFRCh. 16 - Prob. 14QFRCh. 16 - Prob. 15QFRCh. 16 - Prob. 16QFRCh. 16 - Prob. 17QFRCh. 16 - Prob. 18QFRCh. 16 - Prob. 19QFRCh. 16 - Prob. 20QFRCh. 16 - Prob. 21QFRCh. 16 - Prob. 1TQCh. 16 - Prob. 2TQCh. 16 - Prob. 3TQCh. 16 - Prob. 4TQCh. 16 - Prob. 5TQCh. 16 - Prob. 7TQCh. 16 - Prob. 8TQCh. 16 - Prob. 9TQCh. 16 - Prob. 10TQCh. 16 - Prob. 1PCh. 16 - Prob. 2PCh. 16 - Prob. 3PCh. 16 - Prob. 4PCh. 16 - Prob. 5PCh. 16 - Prob. 6PCh. 16 - Prob. 7PCh. 16 - Prob. 8PCh. 16 - Prob. 9PCh. 16 - Prob. 1TYCh. 16 - Prob. 2TYCh. 16 - Prob. 3TYCh. 16 - Prob. 4TYCh. 16 - Prob. 5TYCh. 16 - Prob. 6TYCh. 16 - Prob. 7TYCh. 16 - Prob. 8TYCh. 16 - Prob. 9TYCh. 16 - Prob. 10TY
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