Integrated Science
7th Edition
ISBN: 9780077862602
Author: Tillery, Bill W.
Publisher: Mcgraw-hill,
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Question
Chapter 12, Problem 25CQ
To determine
The several ideas that explain that the shape of Milky Way galaxy is a large and smooth cloud of spiral shape
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Check out a sample textbook solutionStudents have asked these similar questions
1 - If you were to travel straight up from the core of our galaxy and then look
back, you would have a grand view of the Milky Way's spiral shape. If the
distance from the core to the outer edge was 50.000 light-years, how much
surface area are you looking at? Assume the galaxy is a circle whose area can
be found by the equation
Area = Pi * ²
1. Consider our Sun - it is in orbit around the center of our Milky Way Galaxy.
The velocity of the Sun in its orbit is about 250 km/s. The distance to the center
of the galaxy is about 9.1 kpc (kiloparsecs). We can use Kepler's third law to
calculate the mass of the galaxy interior to the Sun's orbit. We assume that the
orbit is circular so that the semimajor axis is just the radius of the circular orbit =
9.1 kpc. First we need to calculate the number of AU's in 9.1 kpc. (Note that 1
Крс - 1000 рс - 3260 1t yrs and 1 pc - 206,265 AU.)
%3D
a =r =9.1kpc = (9.1kpc) 1000 pc 206,265AU]
1kpc
AU
Sun
1pc
In 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.
Chapter 12 Solutions
Integrated Science
Ch. 12.1 - Stars twinkle and planets do not twinkle because...Ch. 12.6 - Prob. 2SCCh. 12.6 - Prob. 3SCCh. 12.6 - Prob. 4SCCh. 12.6 - Prob. 5SCCh. 12.6 - Prob. 6SCCh. 12.6 - Prob. 7SCCh. 12.6 - Prob. 8SCCh. 12.7 - Prob. 9SCCh. 12.7 - Prob. 10SC
Ch. 12.7 - Prob. 11SCCh. 12.7 - Prob. 12SCCh. 12 - What is a light-year, and how is it defined?Ch. 12 - Prob. 2CQCh. 12 - Prob. 3CQCh. 12 - What is the Hertzsprung-Russell diagram?Ch. 12 - Prob. 5CQCh. 12 - Prob. 6CQCh. 12 - Prob. 7CQCh. 12 - Prob. 8CQCh. 12 - Prob. 9CQCh. 12 - Prob. 10CQCh. 12 - Prob. 11CQCh. 12 - Prob. 12CQCh. 12 - Prob. 13CQCh. 12 - Prob. 14CQCh. 12 - Prob. 15CQCh. 12 - Prob. 16CQCh. 12 - Prob. 17CQCh. 12 - Prob. 18CQCh. 12 - Prob. 19CQCh. 12 - Prob. 20CQCh. 12 - Prob. 21CQCh. 12 - Prob. 22CQCh. 12 - Analyze when apparent magnitude is a better scale...Ch. 12 - Prob. 24CQCh. 12 - Prob. 25CQCh. 12 - Prob. 1PEACh. 12 - Prob. 2PEACh. 12 - Prob. 3PEACh. 12 - Prob. 4PEACh. 12 - Prob. 5PEACh. 12 - Prob. 6PEACh. 12 - Prob. 7PEACh. 12 - Prob. 8PEACh. 12 - Prob. 9PEACh. 12 - Prob. 10PEACh. 12 - Prob. 11PEACh. 12 - Prob. 1PEBCh. 12 - Prob. 2PEBCh. 12 - Prob. 3PEBCh. 12 - Prob. 4PEBCh. 12 - Prob. 5PEBCh. 12 - Prob. 6PEBCh. 12 - Prob. 7PEBCh. 12 - Prob. 8PEBCh. 12 - Prob. 9PEBCh. 12 - Prob. 10PEBCh. 12 - Prob. 11PEB
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- 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_forwardObservations indicate that each galaxy contains a supermassive black hole at its center. These black holes can be hundreds of thousands to billions of times more massive than the Sun. Astronomers estimate the size of such black holes using multiple methods. One method, using the orbits of stars around the black hole, is an application of Kepler's third law. The mass of the black hole can be found by using the given equation, where a is the semi-major axis in astronomical units, P is the period in years, and k is a constant with a value of 1 Mo X year²/ AU³. a³ M = k- p² What is the mass of a supermassive black hole if a star orbits it with a semimajor axis of 959 AU and a period of 13.3 years? mass: Another method measures the speed of gas moving past the black hole. In the given equation, v is the velocity of the gas (in kilometers per second), r is the distance of the gas cloud from the black hole (in kilometers), and G is Newton's gravitational constant. In this equation, G = 1.33 ×…arrow_forwardA galaxy with a spherically symmetric distribution of matter has a mass density profile of the type p(r) ∞ 1/r, where r is the radial coordinate from the centre of the galaxy. To what type of circular velocity (r) does this correspond? Select one: a. (r) O b. c. O d. (r) ~ r (r) ~ √r (r): = constantarrow_forward
- Question A6 The Tully-Fischer method relies on being able to relate the mass of a galaxy to its rotation velocity. Stars in the outer-most regions of the Milky Way galaxy, located at a distance of 50 kpc from the galactic centre, are observed to orbit at a speed Vrot = 250 km s-¹. Using Kepler's 3rd Law, determine the mass in the Milky Way that lies interior to 50 kpc. Express your answer in units of the Solar mass.arrow_forwardRecently, astronomers have observed stars and other objects that orbit the center of the Milky Way Galaxy farther out than our Sun, but move around faster than we do. How do astronomers think such an observation can be explained? A, all these faster-moving objects must be escaping from the gravity of the Milky Way and will soon be lost to our Galaxy B. each of the faster-moving outer objects must be the result of a supernova explosion (giving them extra speed) C, it is the Sun that is moving too slowly because of a collision billions of years ago; the outer objects are really moving at the appropriate speed for their distance from the center D there must be a great deal of invisible dark matter outside the orbit of the Sun whose gravitational pull explains the faster motions we see out there E. no one can come up with any explanation for this puzzling observationarrow_forward4. A binary system is composed of two identical stars orbiting each other with some period To. a) Now imagine scaling all lengths (separation between the stars and the radius of the stars) by a factor k, but keeping the density of the stars the same. By what factor does the period change? b) Now instead of scaling the lengths, scale the density by k (i.e. p → kx p). By what factor does the period change?arrow_forward
- 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!arrow_forwardFor a circular velocity profile of the type (r) = ar¹/9, where a is a constant and r is the radial distance from the centre of a spiral galaxy, find the ratio K(r)/(r), where K(r) is the epicyclic frequency and 2(r) is the angular velocity. Enter your answer to 2 decimal places.arrow_forwardRadio maps of the spiral arms of our galaxy a. reveal that our galaxy is a grand design spiral. b. map the location of hot O and B stars by the radio radiation they emit. c. reveal that the spiral arms are winding up and growing closer together. d. reveal that the sun is currently located in the center of a spiral arm. e. map the location of dense neutral hydrogen clouds.arrow_forward
- You observe the H-alpha line of Hydrogen in a distant galaxy to have a wavelength of 754.4 nm. What is the radial velocity of the galaxy? Hint: The rest wavelength of H-alpha is 656 nm.arrow_forwardYou observe the H-alpha line of Hydrogen in a distant galaxy to have a wavelength of 754.4 nm. What is the radial velocity of the galaxy?arrow_forwardThe fact that many radio lobes emit less intensely on the side of the galaxy facing away from Earth suggests that a. they are formed by material falling into the galaxy. b. they are powered by black body radiation. c. they are excited by radiation from nearby galaxies. d. they are powered by the rapid rotation of the galaxy. e. they are created by jets of high-speed matter in magnetic fields, which tend to emit photons in the direction they are moving.arrow_forward
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