The document discusses a conceptual test on astronomy and the Milky Way galaxy. It provides questions and answers about the location of the Galactic center, the location of the Sun in the Milky Way, and characteristics of the Milky Way such as it being a barred spiral galaxy.
2. 1) supernova remnants. 2) white dwarf stars in the spiral arms. 3) red giant variable stars in globular clusters. 4) bright O and B stars in open clusters. 5) X-ray sources. Question 1 The location of the Galactic center was identified using
3. 1) supernova remnants. 2) white dwarf stars in the spiral arms. 3) red giant variable stars in globular clusters. 4) bright O and B stars in open clusters. 5) X-ray sources. Question 1 The location of the Galactic center was identified using Harlow Shapley used pulsating RR-Lyrae variables as distance indicators to the globular clusters. He then deduced the distance and direction of the Milky Way’s center.
4. Question 2 Our Sun is located in the Milky Way Galaxy 1) about 30 kpc from the center in the halo. 2) 30,000 light years from the center in a globular cluster. 3) at the outer edge of the Galactic disk, in the plane. 4) about half-way from the center, in the spiral arms. 5) in the bulge, near the Orion arm.
5. 1) about 30 kpc from the center in the halo. 2) 30,000 light years from the center in a globular cluster. 3) at the outer edge of the Galactic disk, in the plane. 4) about half-way from the center, in the spiral arms. 5) in the bulge, near the Orion arm. Question 2 Our Sun is located in the Milky Way Galaxy The Sun orbits the center of the Galaxy within the disk, taking about 225 million years to complete one orbit.
6. 1) measuring distances with Cepheid variable stars. 2) identifying the mass of the Galaxy’s central black hole. 3) determining the masses of stars in an eclipsing binary system. 4) using spectroscopic parallax to measure distances to stars. Question 3 The Period-Luminosity relationship is a crucial component to
7. 1) measuring distances with Cepheid variable stars. 2) identifying the mass of the Galaxy’s central black hole. 3) determining the masses of stars in an eclipsing binary system. 4) using spectroscopic parallax to measure distances to stars. Question 3 The Period-Luminosity relationship is a crucial component to Cepheid variable stars with longer periods have higher actual luminosities; short-period Cepheids are dimmer.
8. Question 4 High speed motion of gas and stars near the Milky Way Galaxy’s center is explained by 1) tidal forces from the Andromeda Galaxy. 2) accretion disks around neutron stars. 3) gamma-ray bursts. 4) gravitation from globular clusters. 5) a supermassive black hole.
9. 1) tidal forces from the Andromeda Galaxy. 2) accretion disks around neutron stars. 3) gamma-ray bursts. 4) gravitation from globular clusters. 5) a supermassive black hole. Question 4 High speed motion of gas and stars near the Milky Way Galaxy’s center is explained by Recent observations estimate the black hole to be 4 million solar masses.
10. 1) a spiral galaxy. 2) a barred spiral galaxy. 3) an elliptical galaxy. 4) a quasar. 5) an irregular galaxy. Question 5 Detailed measurements of the disk suggest that our Milky Way is
11. 1) a spiral galaxy. 2) a barred spiral galaxy. 3) an elliptical galaxy. 4) a quasar. 5) an irregular galaxy. Question 5 Detailed measurements of the disk suggest that our Milky Way is Measurements of stellar motion in and near the bulge imply that it is football shaped, about half as wide as it is long, characteristic of a barred spiral galaxy.
12. Question 6 What two observations allow us to estimate the Galaxy’s mass? 1) the Sun’s mass and velocity in orbit around the Galactic center 2) the rotation of the bulge and disk components 3) the Sun’s age and age of globular cluster stars 4) the motion of spiral arms and the mass of the central black hole 5) the Sun’s orbital period and distance from the center
13. 1) the Sun’s mass and velocity in orbit around the Galactic center 2) the rotation of the bulge and disk components 3) the Sun’s age and age of the globular cluster stars 4) the motion of spiral arms and mass of the central black hole 5) the Sun’s orbital period and distance from the center Question 6 What two observations allow us to estimate the Galaxy’s mass? Use the modified form of Kepler’s law to find the mass: Total Mass = (orbital size) 3 / (orbital period) 2
14. 1) the spiral arms formed first. 2) the globular clusters formed first. 3) the disk component started out thin and grew. 4) spiral density waves formed first. 5) the bar in the bulge formed first. Question 7 In the formation of our Galaxy
15. 1) the spiral arms formed first. 2) the globular clusters formed first. 3) the disk component started out thin and grew. 4) spiral density waves formed first. 5) the bar in the bulge formed first. Question 7 In the formation of our Galaxy Globular clusters contain very old stars, no gas or dust, and orbit around the center randomly.
16. 1) the waves penetrate dusty cocoons to reveal star formation. 2) it reflects from the Galaxy’s core. 3) the waves are not absorbed by Galactic black holes. 4) it can be used to map out the cool hydrogen in spiral arms. 5) radio waves provide a distance measurement like parallax. Question 8 21-cm radio radiation is useful in studying the Galaxy because
17. 1) the waves penetrate dusty cocoons to reveal star formation. 2) it reflects from the Galaxy’s core. 3) the waves are not absorbed by Galactic black holes. 4) it can be used to map out the cool hydrogen in spiral arms. 5) radio waves provide a distance measurement like parallax. Question 8 21-cm radio radiation is useful in studying the Galaxy because The Doppler shifts of 21-cm radiation from hydrogen in the spiral arms provides astronomers with a tool to map out the Galaxy’s structure.
18. 1) OB associations 2) open clusters 3) giant molecular clouds 4) emission nebulae 5) Population II red giant stars Question 9 Which of these is not a typical part of the Galaxy’s spiral arms?
19. 1) OB associations 2) open clusters 3) giant molecular clouds 4) emission nebulae 5) Population II red giant stars Question 9 Which of these is not a typical part of the Galaxy’s spiral arms? The spiral arms contain gas, dust, molecular clouds, new clusters, and Population I stars.
20. Question 10 1) 21-cm maps of the spiral arms 2) the rotation curve of the outer edges of the Galaxy 3) orbits of open clusters in the disk 4) infrared observations of new star forming regions 5) X-ray images of other galaxies What suggests that the mass of the Galaxy extends farther than its visible disk?
21. 1) 21-cm maps of the spiral arms 2) the rotation curve of the outer edges of the Galaxy 3) orbits of open clusters in the disk 4) infrared observations of new star forming regions 5) X-ray images of other galaxies Question 10 What suggests that the mass of the Galaxy extends farther than its visible disk? The outer edges of the Galaxy’s disk rotate much faster than they should. Most of the mass of the Galaxy must be dark matter.