Concept explainers
To prove:
The density of matter needed for a black hole is inversely proportional to the square of the mass of the black hole.
The mass of a substance having a density equal to water (
Answer to Problem 63Q
Mass of substance with a density of
Explanation of Solution
Given:
The density of the substance used to make the black hole =
Formula used:
Calculation:
When density of the substance used to make the black hole =
Conclusion:
Mass of substance with a density of
Want to see more full solutions like this?
Chapter 21 Solutions
Universe: Stars And Galaxies
- 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_forwardWhat characteristics must a binary star have to be a good candidate for a black hole? Why is each of these characteristics important?arrow_forwardOnce 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_forward
- What causes the largest mass-to-light ratio: gas and dust, dark matter, or stars that have burnt out?arrow_forwardTrue or false The escape speed from a black hole would be greater than the speed of light. If the impact time of a collision is increased, the force of impact will decrease. A size of a Kelvin degree (oK) is larger than a Celsius degree (oC).arrow_forwardWhat indicates that the gravitational wave originated from the merger of a black hole?arrow_forward
- What is the Schwarzschild radius (in km) of a 20 solar mass black hole?arrow_forwardIn 1999, scientists discovered a new class of black holes with masses 100 to 10000 times the mass of our sun, but occupying less space than our moon. Suppose that one of these black holes has a mass of 1x10^3 suns and a radius equal to one-half the radius of our moon. What is the density of the black hole in g/cm^3? The radius of our sun is 7.0x10^5km and it has an average density of 1.4x10^3kg/m^3. The diameter of the moon is 2.16x10^3 miles. Note: the volume of a sphere is V=4/3 pie r^3arrow_forwardUse the result from Exercise 24.21 to calculate the radius of a black hole with a mass equal to: the Earth, a B0-type main-sequence star, a globular cluster, and the Milky Way Galaxy. Look elsewhere in this text and the appendixes for tables that provide data on the mass of these four objects.arrow_forward
- AstronomyPhysicsISBN:9781938168284Author:Andrew Fraknoi; David Morrison; Sidney C. WolffPublisher:OpenStaxFoundations of Astronomy (MindTap Course List)PhysicsISBN:9781337399920Author:Michael A. Seeds, Dana BackmanPublisher:Cengage LearningStars and Galaxies (MindTap Course List)PhysicsISBN:9781337399944Author:Michael A. SeedsPublisher:Cengage Learning
- Stars and GalaxiesPhysicsISBN:9781305120785Author:Michael A. Seeds, Dana BackmanPublisher:Cengage Learning