21st Century Astronomy (sixth Edition)
6th Edition
ISBN: 9780393675504
Author: Laura Kay, Stacy Palen, George Blumenthal
Publisher: W. W. Norton & Company
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Chapter 23.4, Problem 23.4CYU
To determine
The kind of galaxies expected at the redshift of
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What happens when galaxies collide?
A. Star collisions will be rare but the shapes of the galaxies will be largely distorted.
B. The shapes of the galaxies will be largely distorted and many of the stars of one galaxy will collide with stars of the other galaxy.
C. The shapes of the galaxies will be distorted and many stars will collide with stars of the other galaxy, as well as with other stars in the same galaxy.
D. Star collisions will be rare and the two galaxies will just pass through each other without any changes.
Is the answer A? Thank you!
We know that dark matter must exist in galaxies. If not, many of the stars in a galaxy would ...
a.Expand and go supernova due to the expansion of the Universe
b.Fly away from the galaxy because the stars’ velocities are so large, and the galaxy would not have enough gravity to hold onto them
c.Orbit the center of the galaxy normally
d.Spiral in toward the center of the galaxy because most of the galaxy’s mass would be toward the center
What are the angular diameters of the following, as seen from Earth?
a. The Sun, with radius R = Rsun = 7x10^5 km.
b. Betelgeuse, with MV = -5.5 mag, mv = 0.8 mag, and R = 650Rsun.
c. The galaxy M31, with R = 30 kpc at a distance D = 0.7Mpc.
d. The Coma cluster of galaxies, with R = 3 Mpc at a distance D = 100 Mpc.
Chapter 23 Solutions
21st Century Astronomy (sixth Edition)
Ch. 23.1 - Prob. 23.1CYUCh. 23.2 - Prob. 23.2CYUCh. 23.3 - Prob. 23.3CYUCh. 23.4 - Prob. 23.4CYUCh. 23 - Prob. 1QPCh. 23 - Prob. 2QPCh. 23 - Prob. 3QPCh. 23 - Prob. 4QPCh. 23 - Prob. 5QPCh. 23 - Prob. 6QP
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