PH109 Exploring the Universe, Test #4, Spring 2001
Please indicate the best answer to the following questions on the answer sheet provided. Each question is worth 2 ½ points.
1. Who first calibrated the Cepheid variable stars for use in determining distance?
a. Henrietta Leavitt, b. Edwin Hubble, c. John Glenn, d. Carl Sagan, e. Harlow Shapley
2. Which of the following is not a characteristic of the stars of the disk component of our galaxy?
a. circular orbits, b. randomly inclined orbits, c. higher metal abundance
d. young stars, e. star formation regions
3. Younger stars have more heavy elements because
a. old stars destroy heavy elements as they age.
b. young stars burn their nuclear fuels faster.
c. the heavy elements were made in previous generations of stars.
d. heavy elements haven't had time to settle to the core of these younger stars.
4. The center of our galaxy lies in the direction of the constellation of
a. Ursa Minor, b. Ursa Major, c. Sagittarius, d. Orion, e. Monoceros
5. The mass of a single galaxy might be found by
a. the double galaxy method, b. the rotation curve method, c. the cluster method.
d. any of these methods, e. none of these methods
6. Most of the mass of a galaxy is
a. contained in the massive O and B stars in the galaxy.
b. contained in the H I regions of the galaxy.
c. contained in the H II regions of the galaxy.
d. contained in the dark matter of the galaxy.
7. ______galaxies contain large clouds of gas and dust, both young and old stars, but have no obvious spiral arms or nucleus.
a. Irregular, b. S0, c. E7, d. Sa, e. E0
8. For what type of object is the period-luminosity relation used for determining distances?
a. Algol variables, b. Cepheids, c. Cataclysmic variables, d. 21 centimeter radiation.
9. The two dwarf irregular companions of the Milky Way Galaxy are known as the
a. bi-polar nebular, c. M31 and M32, d. Happy and Sleepy, e. large and small Magellanic clouds
10. Why can't we see visible radiation from the central region of the galaxy?
a. no visible light is emitted by the central region of the galaxy
b. interstellar dust blocks our view
c. too many stars are in the way
d. gravity curves the light away from the Earth and Sun
11. The oldest stars in the galaxy are found
a. in globular clusters in the halo, b. at the center of the galaxy
c. on the front rim of spiral arms, d. in the galactic disk
12. What kind of Galaxy do we live in
a. Globular, b. Spiral, c. Elliptical, d. Irregular
13. Which of the following is not found in the Galaxy’s spiral arms?
a) young star clusters, b) O and B stars, c) globular clusters, d) emission nebulae
14. Why are quasars called “quasi-stellar”?
a) Their spectra strongly resemble the spectra of stars.
b) They are ordinary stars located at vast distances from Earth.
c) They look like stars on photographs.
d) Like the stars visible in our night sky, quasars reside within the boundaries of the Milky Way.
15. Which type of galaxy contains the least amount of interstellar material?
a) ellipticals, b) spirals, c) barred spirals, d) irregulars
16. One would expect the HR diagram of an elliptical galaxy to resemble that of a(n)
a) globular star cluster, b) open star cluster, c) star formation region, d) supernova remnant
17. Which of the following would not be useful in determining the distance to another galaxy?
a) parallax, b) Cepheid variables, c) the sizes of HII regions, d) the brightness of a supernova
18. The radio emission from radio galaxies and quasars is due to
a) thermal emission, b) blackbody radiation, c) O and B stars, d) synchrotron radiation
19. What type of galaxy is frequently found at the center of a rich cluster of galaxies?
a) elliptical, b) spiral, c) barred spiral, d) irregular
20. Why do the cores of spiral galaxies appear redder than the arms
a) because of reddening due to dust, b) because the cores are bigger
b) because the cores are further away, d) because of black holes in the center
21. The location of the center of the Galaxy is determined by observations of:
a) Cepheids.
b) Globular clusters.
c) The spiral arms.
d) A visually bright, massive, object around which all objects in the Galaxy move.
22. In the video of the simulation of six galaxies interacting, what was the result
a) they all orbited around each other
b) they drifted away from each other because of the Hubble force
c) they were all cannibalized into one giant galaxy
d) they became neutron galaxies
23. It is unlikely that astronauts will ever pass through black holes because
a) they do not really exist
b) they are too small to hold a person
c) they cannot be found because they are black and cannot be seen
d) tidal forces would rip them apart
24. Elliptical galaxies are reddish in color because they
a) shine because of synchrotron radiation
b) are moving away faster than other galaxies
c) contain relatively few young, hot stars
d) are surrounded by intergalactic dust clouds
25. What two observations of an object allow for a determination of the Milky Way's mass?
a) Object's mass and velocity.
b) Object's age and distance from the galactic center.
c) Object's mass and age.
d) Object's velocity and distance from the galactic center.
26. The two dwarf irregular companions of the Milky Way Galaxy are known as the
a) bi-polar nebular, c) M31 and M32, d) Happy and Sleepy, e) large and small Magellanic clouds
27. The relationship which equates distance with redshift velocity is called
a) Hubble’s Law
b) Law of Redshifts
c) Einstein’s Law
d) Doppler’s Law
28. The growth of a galaxy by devouring multiple companions is called
a) galactic digestion
b) dog eat dog
c) galactic feeding
d) galactic cannibalism
29. Which of the following is an essential part of Einstein's explanation of gravity?
(a) matter causes curvature of space
(b) the gravity of a moving object varies with time
(c) gravitational forces exist only over a limited distance
(d) anti-matter has negative gravity
30. Why can't we see visible radiation from the central region of the galaxy?
(a) no visible light is emitted by the central region of the galaxy
(b) interstellar dust blocks our view, (c) too many stars are in the way
(d) gravity curves the light away from the Earth and Sun
31. How was Hubble able to determine the distances of nearby galaxies?
(a) by using radar
(b) by measuring trigonometric parallaxes
(c) by measuring the typical angular separations of stars in them
(d) by observing Cepheid variables in them
32. The location of the center of the Galaxy is determined by observations of:
a) Cepheids.
b) Globular clusters.
c) The spiral arms.
d) A visually bright, massive, object around which all objects in the Galaxy move.
33. Galaxies which show no flat structural feature, but just a smooth apparently three-dimensional luminosity structure, are called
a) boring, b) spirals, c) irregulars, d) ellipticals
34. What is the most likely source of energy for active galaxies and quasars?
a) Large clusters of very massive, luminous stars.
b) A single supermassive, superluminous star.
c) Accretion onto a supermassive black hole.
d) Numerous supernovae from rapid star formation in young galaxies.
35. 21 cm radiation is produced by which element?
a) hydrogen, b) helium, c) carbon, d) iron
36. We cannot see the other side of the galaxy primarily because our view is blocked by
a) too many stars, b) glowing interstellar gas
c) interstellar dust, d) planetary nebulae and supernova remnants
37. Globular clusters are:
a) great clusters of globs in our galaxy
b) tight collections of a few hundred thousand stars
c) regions of recent star formation
d ) observed mostly by radio telescopes
38. The location of our Sun in the galaxy is approximately
a) near the core
b) near the outer edge
c) about 2/3 of the way out to the edge
d) not currently determined
39. Why don’t we see quasars in our local neighborhood?
a) most quasars happened a long time ago so they are distant
b) there is no room for quasars in our local neighborhood
c) we must wait for their light to e red shifted first
d) the gas and dust from out own galaxy keeps us from seeing them
40. We can best see the spiral structure of our own galaxy by looking in the in which part of the spectrum?
a) infrared, b) visible, c) radio, d) x-ray