ASTRONOMY 101

Mesa College

Spring 2004

Fifth Examination

NAME______________________________(Print) Lec. hr.______ days class meets______

NAME______________________________(Signature) select best answer

1 Which of the following would be considered a population II object?

a. open clusters

b. globular clusters

c. gas and dust

d. O and B stars

e. all of the above

2 The spiral arms of our galaxy have been traced out and explored by observing

a. globular clusters

b. radio emission from neutral hydrogen(21-cm radiation)

c. O and B stars

d. galactic clusters

e. none of the above

3 The sun's location within the Milky Way galaxy was determined primarily by the study of

a. 21-cm radio emission

b. distribution of O and B type stars

c. the fuzzy band in the sky

d. distributions of globular clusters

4 Stars of Population II are almost all old.

a. true b. false

5 The sun is one of about how many stars in the Milky Way galaxy

a. 100 million

b. one billion

c. 100 to 400 billion

d. one trillion

e. We really have no idea of the number of stars in the Milky Way Galaxy.

6 The sun is

a. near the center of the galaxy

b. 2/3 out from the center of the galaxy

c. in a globular cluster

7 Astronomers cannot observe the stars in visible light on the far side of our Galaxy because

a. no telescope is large enough

b. photographic materials are not sensitive enough

c. we are not certain of their locations

d. interstellar dust obscures them

e. none of the above

8 William Herschel first tried to figure out the shape of the Milky Way using "star counts." This technique was based on the idea that: (note: this que. does not ask for the result)

a. There is a limit to how far away stars can be and still remain visible to the naked eye.

b. The Milky Way must be flat.

c. The Milky Way must have a finite size and therefore an edge.

c. The further the Milky Way stretches in any given direction, the more stars which should be visible in that direction.

9 Our most powerful tool for estimating distances to nearby galaxies is

a. globular clusters d. Cepheid variables

b. white dwarfs e. parallax

c. binary stars

10 A super cluster of galaxies is a cluster made up of super massive galaxies.

a. true b. false

11 Which of these objects exhibits the largest red shifts?

a. Virgo A b. a quasar c. Cygnus X-1 d. Crab Nebula

12 Which is a characteristic of a Seyfert galaxy?

a. Faint spiral arms.

b. Nucleus bright with respect to arms.

c. Nucleus that varies in brightness.

d. All of the above.

13 The pattern of Doppler shifts we see among the galaxies indicates that the universe is now

a. expanding c. standing still

b. contracting d. none of these

14 The mysterious "dark matter" is thought to exist because it

a. provides gravitational force but does not emit light

b. blocks the view of more distant H II regions

c. blocks the view of more distant galaxies

d. reddens the light from more distant galaxies

e. reddens the light from more distant stars

15 Spiral galaxies usually

a. contain dust in the disk region

b. are rounder than ellipticals

c. are generally closer to the Milky Way than other types of galaxies

16 Our Milky Way Galaxy is what type of galaxy?

a. spiral b. elliptical c. dwarf elliptical d. irregular

17 Which of the following was not done by Edwin Hubble?

a. measuring the distance to the Andromeda "nebula"

b. classifying the galaxies by their shapes

c. establishing the expansion of the universe

d. discovering the law that the motion of the galaxies away from us is a function of distance

e. discovering the relationship between period and luminosity for cepheid variables

18 Hubble's law states that the velocity of recession of a

a. galaxy is proportional to its distance

b. galaxy is inversely proportional to its distance

c. star is inversely proportional to its distance

d. star is proportional to its distance

e. galaxy is independent of its distance

19 Of the following, which has the greatest flattening?

a. E0 b. E7 c. E3 d. E5

20 The largest(most mass) galaxies are

a. spirals b. irregulars c. globulars e. ellipticals

21 In regards to galaxies, what does the mass to light ratio tell the astronomer?

a. its distance c. its chemical composition

b. its shape d. whether star formation is most likely going on or not

22 What is the believed energy source that powers quasars?

a. star formation c. supernovae explosions

b. star collisions d. super-massive black hole

23 The mass of a galaxy can be found from

a. observing objects in orbit about the galaxy.

b. the width of spectral lines from its stars

c. the number of black holes it contains

d. the mass of gas and dust in its spiral arms

e. measuring the period and brightness of its Cepheids

24 The luminosity of a typical Seyfert galaxy is

a. more than either a normal galaxy or a quasar

b. less than a normal galaxy, but more than a quasar

c. more than a normal galaxy, but less than a quasar

d. less than either a normal galaxy or a quasar

e. unknown, because the distances to Seyferts are unknown

25 Why were quasars called quasi-stellar radio sources?

a. They looked like stars on photographs.

b. They are ordinary (but very luminous) stars located at vast distances from Earth. c. Their spectra strongly resemble those of stars.

d. They are stars which emit very strong radiation in the radio.

26 The cosmological principle states that the large scale structure and composition of the universe is the same everywhere in space for all time.

a. true b. false

27 The 3 deg. K radiation is believed to be the

a. combined light from distant stars

b. combined light from distant galaxies

c. remnant of the early days of the universe

d. redshifted radiation from quasars

28 The distances of the most remote galaxies are based upon

a. the luminosity of the brightest Cepheids

b. the surface brightness of the galaxies

c. the Hubble law of recession

d. the resolution of the H II regions within the galaxies

29 A big success of the concept of an inflationary universe is that it explains why

a. the cosmic background radiation is so uniform

b. galaxies formed in clusters

c. there is a cosmic background radiation

d. galaxies appear larger at greater distances

e. the universe is ten billion years old

30 A way to test whether the universe is open or closed is to

a. determine the density of the universe

b. study the motions of distant globular clusters

c. check the speeds of nearby quasars

d. determine the density of the Milky Way

31 The results of the COBE mission was to

a. discover the first planets orbiting distant star systems.

b. discover the cause of the formation of our solar system.

c. determine the elements found in distant interstellar clouds.

d. find the first evidence of galaxy formation.

32 The fundamental force that holds the protons & neutrons together in the nucleus is:

a. strong nuclear. c. weak nuclear.

b. gravitation. d. electromagnetic.

33 The force that holds stars together is

a. electromagnetic b. gravity c. strong nuclear d. weak nuclear

43 Since all distant objects in the universe appear to be moving away from our Milky Way, we must be fairly close to the center of the universe. a. true b. false

44 In general, galaxies are found in clusters of galaxies.

a. true b. false

45 Which galaxy has the most tightly wound arms?

a. Sa b. Sb c. Sc

34 The smallest(least mass) galaxies are

a. spirals b. irregulars c. globulars e. ellipticals

35 It is suspected that "twin quasars" are

a. identical quasars orbiting each other

b. two images of the same quasar produced by gravitation(lensing)

c. a double image produced by a defect in the telescope

d. produced by a supernova explosion

e. actually binary stars in the Milky Way

36 Of the galaxies in the Local Group, the majority appear to fall into the classification we call

a. spiral b. irregular c. peculiar d. colliding e. elliptical

37 The term The Local Group, refers to

a. the near by stars.

b. a cluster of galaxies at the edge of the visible universe

c. nearby civilizations to us in space.

d. the spiral arm that our Solar System is located in.

e. the cluster of galaxies that our galaxy in located in.

38 Which of the following is the Earth not located in?

a. the solar system d. the universe

b. globular cluster M13 e. the Earth is located in all of these

c. the Milky Way Galaxy

39 The approximate accepted age of the universe is believed to be about

a. 10 million years c. 5 billion years

b. 1 billion years d. 13-15 billion years

40 The giant voids that astronomers are finding are:

a. regions where a number of black holes have cleared out space in the center of a galaxy

b. empty regions between the spiral arms of the Milky Way galaxy

c. huge HII regions, where the powerful radiation from a hot star has cleared out the local interstellar material

d. very large regions of intergalactic space, where relatively few galaxies or galaxy clusters can be found

e. regions inside the brain of college non-science majors where information about astronomy topics should have been located

41 A universe that will continue to expand forever, never stopping, is described as a(n)

a. closed universe c. inflationary universe

b. open universe d. oscillating universe

42 If the universe is closed

a. the galaxies will move apart forever

b. it will eventually fall back in on itself

c. Hubble's law must be wrong

d. it will eventually become static

43 Since all distant objects in the universe appear to be moving away from our Milky Way, we must be fairly close to the center of the universe. a. true b. false

44 In general, galaxies are found in space by themselves, that is, not in clusters of galaxies.

a. true b. false

45 Which galaxy has the most open arms?

a. Sa b. Sb c. Sc

Describe the Inflationary Model of the Universe and discuss how it is different from the old standard model. 3 points

Describe the cause of gravitational lensing. 2 points

Describe, in general terns how our Galaxy was created. 3 points

Is your name on the scantron and examination? ___________(yes or no) 1 point