21st Century Astronomy
6th Edition
ISBN: 9780393428063
Author: Kay
Publisher: NORTON
expand_more
expand_more
format_list_bulleted
Concept explainers
Videos
Question
Chapter 23.4, Problem 23.4CYU
To determine
The kind of galaxies expected at the redshift of
Expert Solution & Answer
Want to see the full answer?
Check out a sample textbook solution
Students have asked these similar questions
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!
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 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
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
Ch. 23 - Prob. 7QPCh. 23 - Prob. 8QPCh. 23 - Prob. 9QPCh. 23 - Prob. 10QPCh. 23 - Prob. 11QPCh. 23 - Prob. 12QPCh. 23 - Prob. 13QPCh. 23 - Prob. 14QPCh. 23 - Prob. 15QPCh. 23 - Prob. 16QPCh. 23 - Prob. 17QPCh. 23 - Prob. 18QPCh. 23 - Prob. 19QPCh. 23 - Prob. 20QPCh. 23 - Prob. 21QPCh. 23 - Prob. 22QPCh. 23 - Prob. 23QPCh. 23 - Prob. 24QPCh. 23 - Prob. 25QPCh. 23 - Prob. 26QPCh. 23 - Prob. 27QPCh. 23 - Prob. 28QPCh. 23 - Prob. 29QPCh. 23 - Prob. 30QPCh. 23 - Prob. 31QPCh. 23 - Prob. 32QPCh. 23 - Prob. 33QPCh. 23 - Prob. 36QPCh. 23 - Prob. 37QPCh. 23 - Prob. 38QPCh. 23 - Prob. 45QP
Knowledge Booster
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, physics and related others by exploring similar questions and additional content below.Similar questions
- 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 centerarrow_forwardWhich of the following might you expect to be an additional consequence of the fact that galaxies contain more mass than expected?A. The gravitational force between galaxies is greater than expected.B. Galaxies appear less bright than expected.C. Galaxies are farther away than expected.D. There are more galaxies than expected.arrow_forwardGalaxy seeds around which galaxies, clusters, and walls grew may have been a. caused by hot dark matter. b. caused by baryons. c. the result of the separation of the electromagnetic and weak forces. d. the result of freezing water molecules shortly after the universe became transparent to photons. e. caused by microscopic random fluctuations in the infant universe.arrow_forward
- 1. If a galaxy is 9.1 Mpc away from Earth and recedes at 511 km/s, what is H0 (in km/s/Mpc)? 2. What is the Hubble time (in yr)? 3. How old (in yr) would the universe be, assuming space-time is flat and the expansion of the universe has not been accelerating?arrow_forwardAstronomers now think that there is a black hole with more than 4 milliion times the mass of our Sun at the center of our galaxy? Roughly how large would the event horizon of such a supermassive black hole be? a. the size of our moon b. about 4 light years across c. about 17 times the size of our sun d. about the size of an atom (so much mass really compresses the event horizon) e. this question can't be answered without knowing what kind of stars were swallowed by the black holearrow_forwardHow do we know there are supermassive black holes driving active galaxies? a. The cores fluctuate over short periods of time, suggesting a small size. b. The gas near the core is moving very rapidly, suggesting high mass. c. The spectra are dominantly in the Balmer region, suggesting they are made of hydrogen. d. both a and b e. both a and carrow_forward
- If a galaxy is 9.0 Mpc away from Earth and recedes at 488 km/s, what is H0 (in km/s/Mpc)? km/s/Mpc What is the Hubble time (in yr)? years How old (in yr) would the universe be, assuming space-time is flat and the expansion of the universe has not been accelerating? How would acceleration change your answer? A.If the expansion of the Universe has been accelerating, the Universe could be substantially younger than the value entered above. BIf the expansion of the Universe has been accelerating, the Universe could be substantially older than the value entered above.arrow_forwardThe evidence leads modern astronomers to conclude that at the cores of active galaxies are supermassive black holes with masses as high as a. ten solar masses. b. a thousand solar masses. c. a million solar masses. d. a billion solar masses.arrow_forwardTrue or False: Dwarf elliptical galaxies and giant ellipticals probably formed in entirely different ways.a. Trueb. Falsearrow_forward
- What is the only viable explanation for so much mass in so small a region at the core of our galaxy? a. a tight cluster of stars b. many neutron stars c. many stellar black holes d. a single massive black hole e. none of the abovearrow_forwardThe supermassive black hole at the center of a galaxy has a mass of 6.5 billion solar masses. If we assume that it is a Schwarzschild black hole, what is the radius of this black hole? A. 18 light hours B. 20 light hours C. 16 light hours D. 14 light hours Is the answer A? S. radius = 3 x 6.5 x 109 x 9.26567-10 = 18.1 light hours Thanks!arrow_forwardIn a spiral galaxy, the orbital speeds of stars far from the galaxy's center distance from the center increases. as the A. increase B. decrease C. are approximately the same D. The answer changes depending on the galaxy.arrow_forward
arrow_back_ios
SEE MORE QUESTIONS
arrow_forward_ios
General Relativity: The Curvature of Spacetime; Author: Professor Dave Explains;https://www.youtube.com/watch?v=R7V3koyL7Mc;License: Standard YouTube License, CC-BY