Astro 201: Review Questions

These are questions from those "game show cards" I often use. The questions are listed first, and you have to scroll to the bottom to find the answers. Topics: The Milky Way, Galaxies, Cosmology, and SETI.


1.   In the Milky Way, where are the globular clusters found?
	a) disk
	b) spheroid

2.   In the Milky Way, where are all/most stars many billions of years old?
	a) disk
	b) spheroid

3.   Collectively, the nucleus, bulge, and halo are known as the ______.

4.   In the Milky Way, where do you find globular clusters?
	a) disk
	b) spheroid

5.   In the Milky Way, where do you find gas and dust?
	a) disk
	b) spheroid

6.   In the Milky Way, where do you find HII regions?
	a) disk
	b) spheroid

7.   What galaxy type does not have dust?

8.   In what part of the galaxy are globular clusters found?

9.   Is the Milky Way at the center of the Universe?

10.  Hydrogen & Helium came from where?

11.  Why can't you see the center of the Milky Way in the optical?

12.  State the formula for the Hubble Law.

13.  What recessional velocity would you expect for a galaxy 100 Mpc 
     distant?  Use H=50 km/s/Mpc.

14. What is the approximate diameter of the Milky Way?

15.  If the average density of matter in the universe is exactly equal to 
     the critical density Pc, the curvature of space is ______________.

16.  What theory was published by Einstein in 1905?

17.  What is the Cosmological Principle?

18.  The ___________time is when gravity freezes out and all four forces of 
     the Universe come together.

19.  Heavy elements were synthesized where?

20.  What is the dark matter problem?

21.  What are open clusters sometimes called?

22.  What is the approximate "size" of the universe?

23.  What are the two main observations that support a hot big bang cosmology?

24.  Is the sun at the center of the galaxy?

25.  What are the two most common spectral types of stars in our galaxy?

26.  A galaxy comprised of mostly young stars is:
	a) disk
	b) spheroid

27.  If the universe has less than the critical density of matter, 
     do we live in an open or closed universe?

28.  Who discovered the expansion of the universe?

29.  Who discovered interstellar extinction?

30.  The Hyades and Pleisades are open or globular clusters?

31.  Are most globular clusters old or young?

32.  What are the two dominant (most massive) galaxies in the local group?

33.  In classifying spiral galaxies, what do the "a" "b" and "c" designations 

34.  In Hubble's "tuning fork" what are the main types of galaxies?

35.  Approximately how many stars does our Galaxy have?

36.  If the average density of matter in the universe is greater than the 
     critical density Pc, we live in a(n) ____________ universe.

37.  What does C.M.B.R. stand for?

38.  What type of clusters are in the disk?

39.  What color are cepheid variable stars?

40.  What is cosmology?

41.  What are the four types of galaxies?

42.  What is evidence of the Big Bang Theory?

43.  When galaxies come together do the stars collide or pass through 
     each other?

44.  How do you find the age of a star cluster?

45.  What is the root cause of these two phenomena:
	galaxy peculiar velocities
	galaxy clustering

46.  There are 3.26 light-years in a parsec.  How many light years in a Mpc?

47.  What is the "peculiar velocity" of a galaxy?

48.  How many light years in a parsec?

49.  State the "Fermi Paradox"?

50.  What is on the left hand side of the equal sign of the Drake equation?

51.  Do astronomers think that UFO abduction stories are valid?

52.  What are the two types of radio emissions looked for in current SETI 

53.  What is the "water hole"?


1.   spheroid

2.   spheroid

3.   spheroid

4.   spheroid

5.   disk

6.   disk

7.   elliptical

8.   halo, bulge, or spheroid

9.   no

10.  nucleosyntheses in the big bang

11.  too much dust extinction

12.   v=Hd

13.  v=Hd
      =(50 km/s/Mpc)(100 Mpc)
      =5000 km/s

14.  30 kiloparsecs,
       30,000 parsecs,
       or 100,000 light-years

15.  flat

16.  the special theory of relativity

17.  the idea that on large scales, the universe looks the same at 
     all locations and in every direction

18.  Planck

19.  in the interiors of massive stars (and in supernova explosions)

20.  the luminous mass of a cluster is not large enough to account for the 
     motions of the galaxy thus a large amount of unobserved mass must be 
     present between the galaxies

21.  associations or Galactic Clusters

22.  10-15 billion light years, or 3,000-6,000 Mpc

23.  Expanding Universe (Hubble Law)
     and the Cosmic Microwave Background Radiation

24.  No
       (it's 8 kpc out, in the midplane of the disk)

25.  K and M-type

26.  disk

27.  open

28.  Hubble

29.  Trumpler

30.  open

31.  old

32.  Milky Way and Andromeda Galaxy

33.  Toward "a" galaxies have bigger bulges (relative to the disks) and the
     spiral arms are wound in a tighter spiral. 
     So "Sc" galaxies have tiny bulges and loosely wound spiral arms.

34.  elliptical, S0, spiral, barred spiral

35.  400 billion

36.  closed

37.  cosmic microwave background radiation

38.  open clusters

39.  yellow

40.  study of the universe

41.  a)spirals
      b)barred spirals

42.  CMBR (cosmic microwave background radiation)
       The Hubble expansion of galaxies

43.  pass through

44.  Find the mass of the brightest & bluest main sequence star.  It's 
     main sequence lifetime is approximately the age of the cluster.

45.  gravity causes both

46.  3.26 million light years. ("M" = "mega" = millions of)

47.  Random, gravity induced motion relative to the Hubble flow.

48.  3.26

49.  "Colonization time for the Milky Way is much shorter than the age of 
     the Galaxy, so if even one civilization has arisen where are they?  
     (They should be here)

50.  The number of technologically advanced civilizations in the Milky Way.

51.  no

52.  a)Beacons: purposeful, loud radio signals
     b)Leakage, "eavesdropping mode", background signals

53.  A wavelength region relatively free of interference, thought to be 
     a likely region to look for extraterrestrial signals.

Last modified: Mon May 3 14:02:45 CDT 1999