Astronomy
1st Edition
ISBN: 9781938168284
Author: Andrew Fraknoi; David Morrison; Sidney C. Wolff
Publisher: OpenStax
expand_more
expand_more
format_list_bulleted
Concept explainers
Videos
Textbook Question
Chapter 24, Problem 21E
Suppose you wanted to know the size of black holes with masses that are larger or smaller than the Sun. You could go through all the steps in Exercise 24.20, wrestling with a lot of large numbers with large exponents. You could be clever, however, and evaluate all the constants in the equation once and then simply vary the mass. You could even express the mass in terms of the Sun’s mass and make future calculations really easy. Show that the event horizon equation is equivalent to saying that the radius of the event horizon is equal to 3 km times the mass of the black hole in units of the Sun’s mass.
Expert Solution & Answer
Trending nowThis is a popular solution!
Students have asked these similar questions
What is the orbital period (in s) of a bit of matter in an accretion disk that is located 6 ✕ 105 km from a 99 M black hole?
Hint:
Use the circular orbit velocity formula,
Vc =
GM
r
.
s
An AGN hosts a central Black Hole of mass 2×1038×1038 kg. The AGN emits at 1/51/5 of the Eddington limit. Find the luminosity of the AGN. Give your answer in Watts to 3 significant figures.
The temperature of the CMB today is
T=2.725 K. Calculate the temperature of
the CMB at redshift z=2000. Choose the
option below that most closely matches
your answer.
Select one:
O a. 9759 K
O b. 3412 K
Ос.
5453 K.
O d. 5450K
Ое. 2000 К
Chapter 24 Solutions
Astronomy
Ch. 24 - How does the equivalence principle lead us to...Ch. 24 - If general relativity offers the best description...Ch. 24 - Einstein’s general theory of relativity made or...Ch. 24 - If a black hole itself emits no radiation, what...Ch. 24 - What characteristics must a binary star have to be...Ch. 24 - A student becomes so excited by the whole idea of...Ch. 24 - What is an event horizon? Does our Sun have an...Ch. 24 - What is a gravitational wave and why was it so...Ch. 24 - What are some strong sources of gravitational...Ch. 24 - Suppose the amount of mass in a black hole...
Ch. 24 - Imagine that you have built a large room around...Ch. 24 - A monkey hanging from a tree branch sees a hunter...Ch. 24 - Why would we not expect to detect X-rays from a...Ch. 24 - Look elsewhere in this book for necessary data,...Ch. 24 - Which is likely to be more common in our Galaxy:...Ch. 24 - If the Sun could suddenly collapse to a black...Ch. 24 - Suppose the people in Figure 24.4 are in an...Ch. 24 - You arrange to meet a friend at 5:00 p.m. on...Ch. 24 - You are standing on a scale in an elevator when...Ch. 24 - Look up G, c, and the mass of the Sun in Appendix...Ch. 24 - Suppose you wanted to know the size of black holes...Ch. 24 - Use the result from Exercise 24.21 to calculate...Ch. 24 - Since the force of gravity a significant distance...
Additional Science Textbook Solutions
Find more solutions based on key concepts
12.52 CP The deepest point known in any of the earth’s oceans is in the Marianas Trench, 10.92 km deep. (a) Ass...
University Physics (14th Edition)
Energy in Thermal Physics Estimate the number of air molecules in an average-sized room.
An Introduction to Thermal Physics
The pV-diagram of the Carnot cycle.
Sears And Zemansky's University Physics With Modern Physics
Rank these elements in order of increasing abundance in the universe: a helium, b hydrogen, c carbon.
Conceptual Integrated Science
A plank, fixed to a sled at rest in frame S, is of length L0 and makes an angle of 0 with the xaxis. Later, the...
Modern Physics
Repeat Problem 79 for the charge distribution = 0(x/L). (Hint: What does this charge distribution resemble at ...
Essential University Physics (3rd Edition)
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
- Which of the following statements about black holes are true? (select all that apply) If you watch someone else fall into a black hole, you will never see him or her cross the event horizon. However, he or she will fade from view as the light he or she emits (or reflects) becomes more and more redshifted. If you fell into a black hole, you would experience time to be running normally as you plunged rapidly across the event horizon. If we watch a clock fall toward a black hole you will see it tick slower and slower as it falls nearer to the event horizon. If the Sun magically disappeared and was replaced by a black hole of the same mass, Earth would soon be sucked into the black hole.arrow_forwardAssume the event horizon is the size of the black hole (it is not: in reality, the black hole is a point source). What is the density of a black hole that has the mass of the Sun in units of kg/cm3? Please express your answer in scientific notation with the "e" format inside the text box, and keep three significant figures (for example, 5.01e3 for 5.01 × 103).arrow_forwardAs a mass m of gas falls into a black hole, at most 0.1mc2 is likely to emerge as radiation; the rest is swallowed by the black hole. Show the Eddington luminosity for a black hole of mass M is equivalent to 2*10-9 Mc2yr-1. Explain why we expect the black hole's mass to grow by at least a factor of e every 5*107 years. Where Edding Luminicity is defined as LE=(4piGMmpc)/(sigmaT), where G is the gravitational constant, M is the mass of the black hole, mp is the mass of a proton, c is the speed of light, and sigmaT is Thomson scattering where sigmaT=6.653*10-25 cm2.arrow_forward
- How much energy could we obtain from 1 kg of hydrogen if it were to undergo nuclear fusion in the interior of a star? The proton mass is 1.00794 amu and the Helium mass is 4.002602 amu. Please please show all calculations and what numbers you are using thank you i will give a thumbs uparrow_forwardThe diagram shows the believed structure of a black hole if viewed from the top and in 3D. Calculate the Schartzchild Radius of a 25 Solar Mass black hole. The Mass of the Sun is 2x10^30kgarrow_forwardA stellar black hole may form when a massive star dies. The mass of the star collapses down to a single point. Imagine an astronaut orbiting a black hole having eight times the mass of the Sun. Assume the orbit is circular. a. Find the speed of the astronaut if his orbital radius is r = 1 AU. b. Find his speed if his orbital radius is r = 11.8 km. c. CHECK and THINK: Compare your answers to the speed of light in a vacuum. What would the astronauts orbital speed be if his orbital radius were smaller than 11.8 km?arrow_forward
- The next step in deciding whether the object in Exercise 25.25 is a black hole is to estimate the density of this mass. Assume that all of the mass is spread uniformly throughout a sphere with a radius of 20 lighthours. What is the density in kg/km3? (Remember that the volume of a sphere is given by V=43R3 .) Explain why the density might be even higher than the value you have calculated. How does this density compare with that of the Sun or other objects we have talked about in this book?arrow_forwardA black hole is an object with mass, but no spatial extent. It truly is a particle. A black hole may form from a dead star. Such a black hole has a mass several times the mass of the Sun. Imagine a black hole whose mass is ten times the mass of the Sun. a. Would you expect the period of an object orbiting the black hole with a semimajor axis of 1 AU to have a period greater than, less than, or equal to 1 yr? Explain your reasoning. b. Use Equation 7.6 to calculate this period.arrow_forwardYou discover by dropping particles into it that the Event Horizon (Schwartzschild Radius) of a black hole is 171 km. How massive is it? (enter just the number in solar masses)arrow_forward
- If the Sun were to magically, and instantly, become a black hole; what would happen to the Earth’s orbit? How does a supernova happen? What makes it different from your run of the mill nova (i.e. why is it so darn super?)?arrow_forwardCalculate your body’s volume.Next, assume that the nuclei are densely packed. Atomic distances are replaced by the radii of the nuclei. What would your body’s volume be like?How tall would you be? Could you become a black hole?arrow_forwardwhat is the mass of the black hole ? give your answer as a multiple of Ms where Ms is the solar mass, Ms = 2.0 * 10^(30) express your answer as a multiple of the solar mass mass Ms.arrow_forward
arrow_back_ios
SEE MORE QUESTIONS
arrow_forward_ios
Recommended textbooks for you
AstronomyPhysicsISBN:9781938168284Author:Andrew Fraknoi; David Morrison; Sidney C. WolffPublisher:OpenStax
Physics for Scientists and Engineers: Foundations...PhysicsISBN:9781133939146Author:Katz, Debora M.Publisher:Cengage Learning
Foundations of Astronomy (MindTap Course List)PhysicsISBN:9781337399920Author:Michael A. Seeds, Dana BackmanPublisher:Cengage Learning
Stars and Galaxies (MindTap Course List)PhysicsISBN:9781337399944Author:Michael A. SeedsPublisher:Cengage Learning
Stars and GalaxiesPhysicsISBN:9781305120785Author:Michael A. Seeds, Dana BackmanPublisher:Cengage Learning
Astronomy
Physics
ISBN:9781938168284
Author:Andrew Fraknoi; David Morrison; Sidney C. Wolff
Publisher:OpenStax
Physics for Scientists and Engineers: Foundations...
Physics
ISBN:9781133939146
Author:Katz, Debora M.
Publisher:Cengage Learning
Foundations of Astronomy (MindTap Course List)
Physics
ISBN:9781337399920
Author:Michael A. Seeds, Dana Backman
Publisher:Cengage Learning
Stars and Galaxies (MindTap Course List)
Physics
ISBN:9781337399944
Author:Michael A. Seeds
Publisher:Cengage Learning
Stars and Galaxies
Physics
ISBN:9781305120785
Author:Michael A. Seeds, Dana Backman
Publisher:Cengage Learning
General Relativity: The Curvature of Spacetime; Author: Professor Dave Explains;https://www.youtube.com/watch?v=R7V3koyL7Mc;License: Standard YouTube License, CC-BY