UNDERSTANDING THE UNIVERSE(LL)-W/CODE
3rd Edition
ISBN: 9780393869903
Author: PALEN
Publisher: NORTON
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Chapter 14, Problem 20QAP
To determine
Reason for the strong radio emissions from the jets of active galactic nuclei.
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An important part of the lifecycle of galaxies like the Milky Way is the self regulation of formation of future generations of stars. Which statement best describes this process?
A) Massive stars explode as Supernovae, heating nearby gas which then can't form stars, and even forcing the gas out of the galaxy in asuperbubble.
B) Low mass stars like our Sun explode as Supernovae, heating nearby gas which then can't form stars, and even forcing the gas out the galaxy in asuperbubble.
C) Stars fuse new elements in their cores which mix with nearby gas clouds, preventing the collapse of the clouds and hence stopping new starformation.
D) The stars lock up material in their cores (like White Dwarf and Neutron Stars) meaning they can act as gravitational seeds for future starformation.
Disk population stars have
I. circular orbits in the plane of the galaxy
II. randomly tipped, elliptical orbits
III. old stars with low metal content
IV. young stars with heavy metal content
a.
I and II
b.
I and III
c.
II and III
d.
II and IV
e.
I and IV
Figure 2 shows the "rotation curve" of
NGC 2742. It plots the “radial velocity
(V)" (how fast material is moving
either toward or away from us) that is
measured for objects at different
distances (R = radius") from the
center of the galaxy. The center of the
galaxy is at 0 kpc (kiloparsecs) with a
speed of 9 km/sec away from us.
(These velocities have been corrected
for the observed tilt of the galaxy and
represent true orbital velocities of the
stars and gas.)
200
100
U4779
-100
As you can see, one side of the galaxy
is moving with a negative velocity
(spinning toward us), while the other
side has a positive velocity (spinning
away from us). Using Newton's
gravity equation, we will be able to
determine the gravitational mass of the
entire galaxy and how the mass varies
versus distance from the galaxy's center.
-200
-8
8
-4
Radius (kpc)
Read the following text carefully and follow the instructions:
Select five radii spaced evenly from 0-10 kpc across the galaxy. Your selections should…
Chapter 14 Solutions
UNDERSTANDING THE UNIVERSE(LL)-W/CODE
Ch. 14.1 - Prob. 14.1CYUCh. 14.2 - Prob. 14.2CYUCh. 14.3 - Prob. 14.3CYUCh. 14.4 - Prob. 14.4CYUCh. 14 - Prob. 1QAPCh. 14 - Prob. 2QAPCh. 14 - Prob. 3QAPCh. 14 - Prob. 4QAPCh. 14 - Prob. 5QAPCh. 14 - Prob. 6QAP
Ch. 14 - Prob. 7QAPCh. 14 - Prob. 8QAPCh. 14 - Prob. 9QAPCh. 14 - Prob. 10QAPCh. 14 - Prob. 11QAPCh. 14 - Prob. 12QAPCh. 14 - Prob. 13QAPCh. 14 - Prob. 14QAPCh. 14 - Prob. 15QAPCh. 14 - Prob. 16QAPCh. 14 - Prob. 17QAPCh. 14 - Prob. 18QAPCh. 14 - Prob. 19QAPCh. 14 - Prob. 20QAPCh. 14 - Prob. 21QAPCh. 14 - Prob. 22QAPCh. 14 - Prob. 23QAPCh. 14 - Prob. 24QAPCh. 14 - Prob. 25QAPCh. 14 - Prob. 27QAPCh. 14 - Prob. 28QAPCh. 14 - Prob. 29QAPCh. 14 - Prob. 30QAPCh. 14 - Prob. 31QAPCh. 14 - Prob. 32QAPCh. 14 - Prob. 33QAPCh. 14 - Prob. 34QAPCh. 14 - Prob. 35QAPCh. 14 - Prob. 36QAPCh. 14 - Prob. 37QAPCh. 14 - Prob. 38QAPCh. 14 - Prob. 39QAPCh. 14 - Prob. 40QAPCh. 14 - Prob. 41QAPCh. 14 - Prob. 43QAPCh. 14 - Prob. 44QAPCh. 14 - Prob. 45QAP
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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
- 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_forwardConsider the Milky Way disk, which has a 50 kpc diameter and a total height of 600 pc. Suppose that the Sun orbits precisely at the mid-plane of the disk in a circular orbit. Supernovae explosions happen randomly throughout the disk at a rate of about 2 per 100 years. Consider a spherical region around the Sun with a radius of 300 pc. Ignore the Milky Way bulge and halo in this problem; assume the Milky Way disk is perfectly uniform and extends all the way through the region of the bulge. (I.e., the Milky Way is modeled *only* as a cylindrical disk--like a hockey puck-- with constant density throughout.) If a particular supernova goes off at a random location within the disk, what is the probability that it went off in the 300 pc radius spherical region near the Sun? Express your probability as a percentage (but without writing the percent sign). [Hint: there is a 100% probability that the supernova went off somewhere in the volume of the Milky Way disk; there is a 50% probability that…arrow_forwardIf a standard passenger aircraft can fly at 0.32 km/s (716 mph), how long (in yr) would it take to reach the sun? ______ yr How long (In yr) would it take to reach the galactic center? (Note: 1 pc = 3.1 x 10^13 km. The radius of the suns orbit around the galactic center is approximately 8,300 pc.) ______ yrarrow_forward
- The mass of the interstellar medium is determined by a balance between sources (which add mass) and sinks (which remove it). Make a table listing the major sources and sinks, and briefly explain each one.arrow_forwardHow does the presence of an active galactic nucleus in a starburst galaxy affect the starburst process?arrow_forwardA Type la supernova explodes in a galaxy at a distance of 6.10×107 light-years from Earth. If astronomers detect the light from the supernova today, how many years T have passed since the supernova exploded? T= 2.07 x10 -5 years Given a Hubble constant of 74.3 km/s/Mpc, at what speed v is this galaxy moving away from Earth? v= km/s What is this galaxy's redshift? redshift:arrow_forward
- A two-arm spiral density wave is moving through the Galactic disk. At the 8-kpc radius of the Sun's orbit around the Galactic center, the wave's speed is 120 km/s, and the Galactic rotation speed is 220 km/s. How many times has the Sun passed through a spiral arm since the Sun formed 4.6 billion years ago?arrow_forwardGlobular 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? (If you would like to learn more about globular clusters, read Section 22.2 of the book, though it is not necessary to answer this question)arrow_forwardThe Milky Way grew through merging with many smaller galaxies. What are the observational signatures of this process? O The motion of old stars in the bulge and halo of our galaxy are randomly orientated, meaning they were formed from collisions of small, accreted, galaxies all on different paths. O The ordered motion of the bulge / halo stars means that they came from many objects. The random motions of stars in the disk means it was formed from collisions of small, accreted, galaxies. O The motion of young stars in the disk are all in the same direction, meaning they came in as seperate objects.arrow_forward
- The traditional theory of the formation of our galaxy CANNOT explain a. the existence of the disk of the galaxy. b. the fact that the oldest stars in the galaxy are not metal free. c. the spherical distribution of the globular clusters. d. the difference in metal abundance of the population I and II stars. e. the existence of the nuclear bulge.arrow_forwardSuppose you have obtained spectra of several galaxies and have measured the observed wavelength of the H-Alpha line (rest wavelength = 656.3 nm) to be Galaxy 1: 658.1 nm. Galaxy 2: 667.1 nm. Galaxy 3: 677.6 nm. Calculate the radial velocity of each of these galaxies.arrow_forwardA star at a distance of 50000 light years from the center of a galaxy has an orbital speed of 100 km/s around the galactic center. What is the total mass of the galaxy located at distances smaller than 50000 light years from the center? A. 7.6 ×1010 solar masses B. 4.2 ×1011 solar masses C. 3.5 ×1010 solar masses D. 1.4 ×1011 solar masses Is the answer C? M = (r x v^2) / G = 50000 x 9.46e15 x (100000^2) / 6.67e-11 / 2e30 (the Sun's mass) = 3.55e10 solar massesarrow_forward
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