Download PH109 Exploring the Uiverse, Test #4, Spring, 1999

PH109 Exploring the Universe, Test #4, Spring, 1999
Name______________________________________
Please indicate the best answer to the following question on the answer sheet provided. Do
not answer the essay questions on the answer sheet as these are graded separately. All
questions are worth two points unless indicated otherwise.
1. For what type of object is the period-luminosity relation used for determining distances?
a) RR Lyrae variables, b) Cepheids, c) Cataclysmic variables, d) 21 centimeter radiation.
2. 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.
3. Which of the following is not found in the Galaxy's halo?
a) globular clusters
b) old stars
c) stars with random, three dimensional orbits
d) red stars
e) star formation regions
4. Collisions between galaxies:
a) Turn ellipticals into spirals, b) May cause bursts of star formation.
c) Cause large numbers of stars to collide and explode, d) Never occur
5. In a lobe radio galaxy, the ultimate energy source for the entire galaxy is thought to reside:
a) In the lobes, b) In the galaxy's center, c) In the jets, d) anti-matter
6.
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
7. How long does it takes the Sun to travel around the center of the Galaxy
a) one billion years, b) 250 million years, c) one million years, d) 5 billion years
8. 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
9. The closest star formation region which can also be seen with the unaided eye
a) Orion nebula, b) ring nebula, c) globular cluster, d) Cyngus Cluster
10. Why do stars evolve
a) Gravity eventually wears out
b) they use up their fuel
c) stars try to merge with other stars thus reforming the star formation region
d) the universe is expanding
11. What classification do we give a star where degenerate electrons prevent the outer layers of the star from
collapsing in on itself
a) main sequence, b) white dwarf, c) neutron star, d) black hole
12. What classification do we give a star where degenerate neutrons prevent the outer layers of the star from
collapsing in on itself
a) main sequence
b) white dwarf
c) neutron star
d) black hole
13. Black holes are
a) creations of science fiction writers
b) the result of stars too massive for neutrons to support them
c) condensed molecular clouds before star formation takes place
d) small dark spot seen on the surface of the Sun
14. 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
15. In the simulation we saw in class, what was the result of six galaxies interacting in a cluster
a) they all collapsed into one large galaxy
b) they were all destroyed
c) they were propelled out of the cluster
d) they formed a chain of galaxies
16. 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
17. Einstein’s ring is
a) a planetary nebula
b) when the image of one galaxy gravitationally distorts the image of another
c) the effect that people living on the surface of a “balloon” can look all the way around forming a ring
d) a treasured heirloom passed from astronomer to astronomer
18. Who is the astronomer who cataloged nuisance nebulae
a) Einstein
b) Galileo
c) Messier
d) Hubble
19. The size of our galaxy is about
a) 3 light years
b) 120 thousand light years
c) one mega parsec
d) unknown at the present
20. As matter streams into a black hole it usually forms what kind of structure
a) accretion disk
b) spherical shell
c) a dark nebula
d) star formation region
21. The heaviest elements on Earth were originally created by
a) Volcanoes
b) the big bang
c) super novae
d) black holes
22. 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
23. The growth of a galaxy by devouring multiple companions is called
a) galactic digestion
b) dog eat dog
c) galactic feeding
d) galactic cannibalism
24. The stars located in the lower left corner of the HR diagram are
(a) white dwarfs, (b) main sequence stars, (c) giants, (d) supergiants
25. All the stars in a cluster are usually assumed to have the same
(a) age, (b) mass, (c) temperature, (d) main sequence lifetime
26. 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
27. If the Sun were replaced by a black hole having a mass of one solar mass, what would happen to the Earth's
orbit?
(a) the Earth would spiral inward
(b) the Earth would jump to a smaller orbit
(c) the size of the Earth's orbit would increase rapidly
(d) the Earth's orbit would remain the same
28. 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
29. 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
30. 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.
31. 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.
32. 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
33. How long does it takes the Sun to travel around the center of the Galaxy
a) one billion years, b) 250 million years, c) one million years, d) 5 billion years
34. 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
35. After our Sun expands and engulfs the Earth in its red giant stage, what will be its final fate.
a) become a nova
b) become a neutron star
c) become a white dwarf
d) become a pulsar
36. The heaviest elements on Earth were originally created by
a) Volcanoes
b) the big bang
c) super novae
d) black holes
37. The growth of a galaxy by devouring multiple companions is called
a) galactic digestion
b) dog eat dog
c) galactic feeding
d) galactic cannibalism
38. 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
39. If the Sun were replaced by a black hole having a mass of one solar mass, what would happen to the Earth's
orbit?
(a) the Earth would spiral inward
(b) the Earth would jump to a smaller orbit
(c) the size of the Earth's orbit would increase rapidly
(d) the Earth's orbit would remain the same
40. Which wavelength would you choose to study star formation
a) infrared
b) visible
c) gamma ray
d) ultra violet
41. (10 points) Explain the differences between spiral, irregular, and elliptical galaxies
42. Name five different techniques we use to measure distances in astronomy.