Astronomy
1st Edition
ISBN: 9781938168284
Author: Andrew Fraknoi; David Morrison; Sidney C. Wolff
Publisher: OpenStax
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Textbook Question
Chapter 27, Problem 8E
Why were quasars and active galaxies not initially recognized as being “special” in some way?
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Chapter 27 Solutions
Astronomy
Ch. 27 - Describe some differences between quasars and...Ch. 27 - Describe the arguments supporting the idea that...Ch. 27 - In what ways are active galaxies like quasars but...Ch. 27 - Why could the concentration of matter at the...Ch. 27 - Describe the process by which the action of a...Ch. 27 - Describe the observations that convinced...Ch. 27 - Why do astronomers believe that quasars represent...Ch. 27 - Why were quasars and active galaxies not initially...Ch. 27 - What do we now understand to be the primary...Ch. 27 - What is the typical structure we observe in a...
Ch. 27 - What evidence do we have that the luminous central...Ch. 27 - Suppose you observe a star-like object in the sky....Ch. 27 - Why don’t any of the methods for establishing...Ch. 27 - One of the early hypotheses to explain the high...Ch. 27 - A friend of yours who has watched many Star Trek...Ch. 27 - Could the Milky Way ever become an active galaxy?...Ch. 27 - Why are quasars generally so much more luminous...Ch. 27 - Suppose we detect a powerful radio source with a...Ch. 27 - A friend tries to convince you that she can easily...Ch. 27 - Show that no matter how big a redshift (z) we...Ch. 27 - If a quasar has a redshift of 3.3, at what...Ch. 27 - If a quasar is moving away from us at v/c=0.8 ,...Ch. 27 - In the chapter, we discussed that the largest...Ch. 27 - Rapid variability in quasars indicates that the...Ch. 27 - Large redshifts move the positions of spectral...Ch. 27 - Once again in this chapter, we see the use of...Ch. 27 - In the Check Your Learning section of Example...Ch. 27 - In the Check Your Learning section of Example...Ch. 27 - The quasar that appears the brightest in our sky,...
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- Why don’t any of the methods for establishing distances to galaxies, described in Galaxies (other than Hubble’s law itself), work for quasars?arrow_forwardWhat are the advantages and disadvantages of using quasars to probe the early history of the universe?arrow_forwardCould the Milky Way ever become an active galaxy? Is it likely to ever be as luminous as a quasar?arrow_forward
- Why are quasars generally so much more luminous (why do they put out so much more energy) than active galaxies?arrow_forwardIn what ways are active galaxies like quasars but different from normal galaxies?arrow_forwardPretend that galaxies are spaced evenly, 4.0 Mpc apart, and the average mass of a galaxy is 1.0 x 101 M What is the average density (in kg/m³) of matter in the universe? (Note: The volume of a sphere is 4 -ar, and the mass of the sun is 2.0 x 1030 kg.) kg/m3 Which model universe does this density value support? flat open closedarrow_forward
- What Hubble constant corresponds to an approximate age of the universe of 1010 y? To get an approximate value, assume the expansion rate is constant and calculate the speed at which two galaxies must move apart to be separated by 1 Mly (present average galactic separation) in a time of 1010 yarrow_forwardSuppose there exists a hypothetical galaxy with mass MG around the center of which a solar system with mass Ms orbits with period T and radius r. Use the formula T = 2n(r³/GMG)¹/2 to calculate T if: MG = 1 x 1040 kg Ms = 2 x 1028 kg • R = 2.5 x 1020 m . .arrow_forwardIf a galaxy has a radial velocity of 21,641 km/s, what is its expected distance from the Hubble Law? Assume that the Hubble Constant is 71 km/s/Mpc. Answer in Mpcarrow_forward
- Observations of quasars have shown us that many are extremely _________, emitting more energy than all the stars in a galaxy. The energy they give off comes from a very small volume, typically about the size of ___________. Some have long ______, shooting off in opposite directions. Today, astronomers understand that all the properties of quasars can be explained if they are __________ at the centers of galaxies. Astronomers can use _____________ to study images and spectra of the central regions of galaxies more clearly than earlier instruments.arrow_forwardIs the appearance of a quasar changing over time a sign that it has entered a new physical state, or are these objects just the extreme outliers of quasars at low activity?arrow_forwardIf Hubble’s constant is taken to be 70 ??? ???, and a quasar is found to have a radial velocity equal to 95% of the speed of light, how far is the quasar in Mpc? (Hint: Use Hubble’s Law and solve for the distance; and the speed of light in vacuum is: ?=3.0×105 ??/?).arrow_forward
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