Geography Assignment 4


1) Which statement about the Milky way Galaxy is correct?

  • Our Galaxy is but one of many galaxies.
  • Our Galaxy contains all stars in the universe.
  • AII stars in our Galaxy take the same time to complete one orbit.
  • Most stars in our Galaxy are in the central bulge.
  • None of the stars in our Galaxy move.

2) What observations led Harlow Shapley to conclude that we are not at the center of the Galaxy?

3) What evidence indicates that a supermassive black hole is located at the center of our Galaxy?

4) Which of the following statements about the motion of galaxies is correct?

  • All galaxies are moving apart.
  • Superclusters of galaxies are all moving apart.
  • Superclusters of galaxies are all moving toward each other.
  • The Milky Way Galaxy is at the center of the universe.
  • All clusters of galaxies in each supercluster are moving toward each other

5) In spiral galaxies, what spectral classes of stars are only found in spiral arms?

6) Briefly describe how the spiral density wave theory accounts for the existence of spiral arms in some spiral galaxies.

7) What two things does the engine of a quasar contain?

  • supermassive black hole and a binary companion
  • stellar-mass black hole and a binary companion
  • supermassive black hole and an accretion disk
  • stellar-mass black hole and an accretion disk
  • supergiant star and an accretion disk

8) Suppose you suspected a certain object in the sky to be a quasar. what sort of observations would you perform to confirm your hypothesis?

9) Inflation most directly explains which of the following?

  • Why the universe is homogeneous
  • Why the universe is expanding
  • why the universe is going to last forever
  • why the universe has a background temperature
  • Why the universe has particles

10) Explain the difference between a Doppler redshift and a cosmological redshift

11) Where do astronomers believe most of the photons in the cosmic microwave background originated?

12) Try using the Drake equation with values that you find reasonable. How many civilizations do you estimate there are in our Galaxy?