PH109 Exploring the Universe, Fall 00, TEST 4
NAME______
Please indicate the best answer to the following questions on the answer sheet provided. All questions are worth 4 points unless noted otherwise.
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 chemical abundance of population I stars
a. indicates that they were formed before the population II stars.
b. indicates that the material they formed from had been enriched with material from supernovae.
c. indicates that they contain very few heavy metals compared to halo stars.
d. depends on the temperature of the star.
e. depends on the mass of the star.
5. 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
6. Observations of galaxies and clusters of galaxies indicate that about _____ per cent of the universe is dark matter.
a. 25, b. 50, c. 75, d. 95
7. A Type II Cepheid has been located in a distant globular cluster with a
period of 10 days, what is the star's absolute magnitude?
a. –1, b. 0, c. –4, d. -6
8. 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
9. 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.
10. Galactic cannibalism refers to
a. binary galaxies.
b. the merging of galaxies.
c. galaxies drawing in gas from the intergalactic medium.
d. the destruction of a galaxies globular clusters by the galaxies nucleus.
11. ______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
12. The Milky Way galaxy is part of
a. the Virgo cluster, b. the Large Magellanic Cloud, c. the Small Magellanic Cloud
d. the Local Group, e. a rich cluster
13. 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.
14. Why is our galaxy in the shape of a disk
a. because it rotates
b. because it got sheered off during a galactic collision
c. the outer parts were torn away by the Magallenic clouds
d. the dark matter holds it in that formation
15. 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
16. The distribution of matter in a galaxy can be found by measuring
a. the number of stars, b. the rotation curve
c. number of pulsars, d. how thick a galaxy is
17. 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
18. 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.
19. 21 cm radiation is produced by which element?
a. hydrogen, b. helium, c. carbon, d. iron
20. 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
21. Why do the Magellanic clouds have their name
a. people thought they were magical, b. named after their discoverer
c. they form a large “M” in the sky, d. the name McDonalds was already taken
22. What kind of Galaxy do we live in
a. Globular, b. Spiral, c. Elliptical, d. Irregular
23. What is the name of the nearest large galaxy to our own
a. Milky Way, b. Andromeda, c. Orion, d. Cygnus
24. If a galaxy is determined to be 2 million light years away, what does that mean
a. it takes light 2 million years to cross the galaxy
b. stars did not turn on till about 2 million years ago
c. it takes light 2 million years to reach us from the galaxy
d. if we could put our galaxy 2 million light years away it would look as bright as that galaxy.
25. Hubble’s law states that:
a. putting telescopes in space will cost approximately ten times more than ground based telescopes
b. the recession of one galaxy must equal the precession of another
c. the faster a galaxy moves away from us the more massive it is
d. the faster a galaxy moves away from us the farther away it is