FiltersDone

Question type

Essay

Multiple Choice

Short Answer

True False

Matching

Exam 10: Galaxies

Show Answer

Share

---

All types

Filters

Study FlashcardsPractice ExamLearn

Question 31

Multiple Choice

Review LaterAdd Note

Review Later

If Galaxy A is found to have a recessional velocity four times greater than that of Galaxy B,what can you say about their relative distances from Earth?

A) Galaxy A is one quarter as far away as Galaxy B.
B) Galaxy A is half as far away as Galaxy B.
C) Galaxy A is twice as far away as Galaxy B.
D) Galaxy A is four times as far away as Galaxy B.

Correct Answer

verified

Show Answer

Question 32

Multiple Choice

Review LaterAdd Note

Review Later

Based on statistical studies,what is the most common type of galaxy in the universe expected to be?

A) barred spiral galaxies
B) dwarf elliptical galaxies
C) irregular galaxies
D) giant elliptical galaxies

Correct Answer

verified

Show Answer

Question 33

Multiple Choice

Review LaterAdd Note

What property of a galaxy do you need to measure before you can determine its size or luminosity?

The high ____________________ of quasars reveals to astronomers that they must be very distant.

Quasar redshifts are usually larger than the redshifts of the visible galaxies.

Which of the following is the best example of a selection effect?

The rapid fluctuations of quasars show that the energy-emitting portions of these objects must be very small.

What is the major observational difference between a Seyfert galaxy and a normal spiral galaxy?

The spectrum of a(n)____________________ consists of a continuum and a few highly redshifted emission lines due to hydrogen.

Describe how the effect of gravitational lensing can produce multiple images of the same quasar.

Cepheid variable stars are more luminous than the Sun.

What process is most likely to turn a dormant black hole at the centre of a galaxy into an active galactic nucleus?

Measuring the Doppler shift of material at various distances from the centre of a galaxy can be used to construct a(n)____________________ for that galaxy.

Explain why good distance indicators must be luminous objects.Why must they be unambiguously recognizable?

A(n)____________________ is observed if our line of sight is along the rotation axis of an active galactic nucleus.

Elliptical galaxies are primarily made up of massive O and B stars.

If a disk galaxy is reasonably close and edge-on,the Doppler shift of the galaxy disk material relative to the centre can be measured at several distances from the galaxy's centre.What does this measurement tell us about the galaxy?

Which of the following generally contain well over 1000 galaxies (mainly ellipticals) packed closely together?

If you wanted to measure the distance to a galaxy,what kind of objects within it could you observe?

What is the Hubble constant essentially a measure of?