COSMIC PERSPECTIVE
9th Edition
ISBN: 9780135729458
Author: Bennett
Publisher: PEARSON
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Chapter 21, Problem 34EAP
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To explain: The evidence for the existence of the supermassive black holes.
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Indicate whether the following statements are true or false. (Select T-True, F-False. If the first is T and the rest F, enter TFFFFF).
A) The nearest large spiral Galaxy, similar in size to the Milky Way, is the Andromeda Galaxy (M31). It is located about 2 million light years from Earth.
B) On very large scales, matter in the Universe is distributed in clumps and voids.
C) RR Lyrae and Cepheid variable stars are used to measure the distance to nearby galaxies.
D) Distances to most stars in the Milky Way are measured by parallax.
E) If we find an O type star in our galaxy, it must be in the disk.
F) The disk of the Milky Way galaxy is about 1,000,000 light years in diameter.
Are the galaxies red-shifting or blue-shifting? Explain. (You may find the big-bang theory helpful). Andromeda galaxy is currently approaching our galaxy with a radial velocity of 266 km/sec. How far is our galaxy from Andromeda? (Hubble’s constant, H, is 73 km/sec/MParsec). When can the two galaxies be anticipated to collide?
The figure below shows the spectra of two galaxies A and B.
Please can i get help with this questions below:
1. Which of these galaxies has ongoing star formation? How can you tell?2. One of these galaxies has Hubble type E3 while the other is SBb. Which is which? What does the 3 inE3 tell you about the galaxy? What does the SB in SBb tell you about the galaxy?3. What effects would dust have on the two spectra?4. Which galaxy would you expect to have more far-infrared emission? Expl
Chapter 21 Solutions
COSMIC PERSPECTIVE
Ch. 21 - Prob. 1VSCCh. 21 - Prob. 2VSCCh. 21 - Prob. 3VSCCh. 21 - Prob. 4VSCCh. 21 - Prob. 1EAPCh. 21 - Prob. 2EAPCh. 21 - Prob. 3EAPCh. 21 - Prob. 4EAPCh. 21 - Prob. 5EAPCh. 21 - Prob. 6EAP
Ch. 21 - Prob. 7EAPCh. 21 - Prob. 9EAPCh. 21 - Prob. 10EAPCh. 21 - Prob. 11EAPCh. 21 - Prob. 12EAPCh. 21 - Prob. 13EAPCh. 21 - Prob. 14EAPCh. 21 - Prob. 15EAPCh. 21 - Prob. 16EAPCh. 21 - Prob. 17EAPCh. 21 - Prob. 18EAPCh. 21 - Prob. 19EAPCh. 21 - Prob. 20EAPCh. 21 - Prob. 21EAPCh. 21 - Prob. 22EAPCh. 21 - Prob. 23EAPCh. 21 - Prob. 24EAPCh. 21 - Prob. 25EAPCh. 21 - Prob. 26EAPCh. 21 - Prob. 27EAPCh. 21 - Prob. 28EAPCh. 21 - Prob. 29EAPCh. 21 - Prob. 30EAPCh. 21 - Prob. 31EAPCh. 21 - Prob. 32EAPCh. 21 - Prob. 34EAPCh. 21 - Prob. 36EAPCh. 21 - Life Story of a Spiral. Imagine that you are a...Ch. 21 - Prob. 39EAPCh. 21 - Prob. 40EAPCh. 21 - Prob. 41EAPCh. 21 - Prob. 42EAPCh. 21 - Prob. 43EAPCh. 21 - Prob. 44EAPCh. 21 - Prob. 45EAPCh. 21 - Prob. 46EAPCh. 21 - Prob. 47EAPCh. 21 - A Nearby Starburst. The galaxy M82, shown in...Ch. 21 - Prob. 49EAPCh. 21 - Prob. 50EAPCh. 21 - Prob. 51EAPCh. 21 - Prob. 52EAPCh. 21 - Prob. 53EAP
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- Once again in this chapter, we see the use of Kepler’s third law to estimate the mass of supermassive black holes. In the case of NGC 4261, this chapter supplied the result of the calculation of the mass of the black hole in NGC 4261. In order to get this answer, astronomers had to measure the velocity of particles in the ring of dust and gas that surrounds the black hole. How high were these velocities? Turn Kepler’s third law around and use the information given in this chapter about the galaxy NGC 4261-the mass of the black hole at its center and the diameter of the surrounding ring of dust and gas-to calculate how long it would take a dust particle in the ring to complete a single orbit around the black hole. Assume that the only force acting on the dust particle is the gravitational force exerted by the black hole. Calculate the velocity of the dust particle in km/s.arrow_forwardWhat are the two best ways to measure the distance to a distant, isolated spiral galaxy, and how would it be measured?arrow_forwardThe globular clusters revolve around the Galaxy in highly elliptical orbits. Where would you expect the clusters to spend most of their time? (Think of Kepler’s laws.) At any given time, would you expect most globular clusters to be moving at high or low speeds with respect to the center of the Galaxy? Why?arrow_forward
- The first clue that the Galaxy contains a lot of dark matter was the observation that the orbital velocities of stars did not decreases with increasing distance from the center of the Galaxy. Construct a rotation curve for the solar system by using the orbital velocities of the planets, which can be found in Appendix F. How does this curve differ from the rotation curve for the Galaxy? What does it tell you about where most of the mass in the solar system is concentrated?arrow_forwardSuppose you were Hubble and Humason, working on the distances and Doppler shifts of the galaxies. What sorts of things would you have to do to convince yourself (and others) that the relationship you were seeing between the two quantities was a real feature of the behavior of the universe? (For example, would data from two galaxies be enough to demonstrate Hubble’s law? Would data from just the nearest galaxies-in what astronomers call “the Local Group”-suffice?)arrow_forwardSuppose somebody proposed that rather than invoking dark matter to explain the increased orbital velocities of stars beyond the Sun’s orbit, the problem could be solved by assuming that the Milky Way’s central black hole was much more massive. Does simply increasing the assumed mass of the Milky Way’s central supermassive black hole correctly resolve the issue of unexpectedly high orbital velocities in the Galaxy? Why or why not?arrow_forward
- Given that only about 5% of the galaxies visible in the Hubble Deep Field are bright enough for astronomers to study spectroscopically, they need to make the most of the other 95%. One technique is to use their colors and apparent brightnesses to try to roughly estimate their redshift. How do you think the inaccuracy of this redshift estimation technique (compared to actually measuring the redshift from a spectrum) might affect our ability to make maps of large-scale structures such as the filaments and voids shown in Figure 28.21? Figure 28.21 Sloan Digital Sky Survey Map of the Large-Scale Structure of the Universe. This image shows slices from the SDSS map. The point at the center corresponds to the Milky Way and might say “You Are Here!” Points on the map moving outward from the center are farther away. The distance to the galaxies is indicated by their redshifts (following Hubble’s law), shown on the horizontal line going right from the center. The redshift z=/ , where is the difference between the observed wavelength and the wavelength emitted by a nonmoving source in the laboratory. Hour angle on the sky is shown around the circumference of the circular graph. The colors of the galaxies indicate the ages of their stars, with the redder color showing galaxies that are made of older stars. The outer circle is at a distance of two billion light-years from us. Note that red (older stars) galaxies are more strongly clustered than blue galaxies (young stars). The unmapped areas are where our view of the universe is obstructed by dust in our own Galaxy. (credit: modification of work by M. Blanton and the Sloan Digital Sky Survey)arrow_forwardExplain where in a spiral galaxy you would expect to find globular clusters, molecular clouds, and atomic hydrogen.arrow_forwardWhen comparing two isolated spiral galaxies that have the same apparent brightness, but rotate at different rates, what can you say about their relative luminosity?arrow_forward
- Determine the wavelength of the standard 21-cm hydrogen spectral line that we receive from the galaxy described in the preceding problem. Could such a large redshift lead astronomers to mistake this spectral line for another one that has an intrinsically longer wavelength?arrow_forwardA 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.arrow_forwardIndicate whether the following statements are true or false. (Select T-True, F-False. If the first is T and the rest F, enter TFFFFF). A) If we find an O type star in our galaxy, it must be in the disk. B) The nearest large spiral Galaxy, similar in size to the Milky Way, is the Andromeda Galaxy (M31). It is located about 2 million light years from Earth. C) The disk of the Milky Way galaxy is about 100,000 light years in diameter. D) On very large scales, matter in the Universe is distributed in clumps and voids. E) Distances to most stars in the Milky Way are measured by parallax. F) RR Lyrae and Cepheid variable stars are used to measure the distance to nearby galaxies.arrow_forward
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