Question 1

How does a lenticular galaxy differ from a normal spiral galaxy?

Accepted Answer

A) It has no bulge. 
B) It has an elongated bulge resembling a bar more than a sphere. 
C) It is flatter in shape. 
D) It has no gas or dust. 
E) It has no spiral arms. 
A) It has no bulge. 
B) It has an elongated bulge resembling a bar more than a sphere. 
C) It is flatter in shape. 
D) It has no gas or dust. 
E) It has no spiral arms.

Question 2

What is the most accurate way to determine the distance to a very distant irregular galaxy?

Accepted Answer

A) using Cepheid variables 
B) using a white-dwarf supernova as a standard candle 
C) main sequence fitting 
D) Hubble's law 
A) using Cepheid variables 
B) using a white-dwarf supernova as a standard candle 
C) main sequence fitting 
D) Hubble's law

Question 3

What two observable properties of a Cepheid variable are directly related to one another?

Accepted Answer

A) the period between its peaks of brightness and its distance 
B) its luminosity and its mass 
C) the period between its peaks of brightness and its luminosity 
D) its mass and its distance 
A) the period between its peaks of brightness and its distance 
B) its luminosity and its mass 
C) the period between its peaks of brightness and its luminosity 
D) its mass and its distance

Question 4

Suppose that we look at a photograph of many galaxies.Assuming that all galaxies formed at about the same time,which galaxy in the picture is the youngest?

Accepted Answer

A) the one that is reddest in color 
B) the one that is bluest in color 
C) the one that is farthest away 
D) the one that is closest to us 
E) the one that appears smallest in size 
A) the one that is reddest in color 
B) the one that is bluest in color 
C) the one that is farthest away 
D) the one that is closest to us 
E) the one that appears smallest in size

Question 5

All galaxies start out as members of the blue cloud,but some transition to the red sequence.

Accepted Answer

A) True 
 B)False

Question 6

Compared to spiral galaxies,elliptical galaxies are

Accepted Answer

A) redder and rounder. 
B) redder and flattened. 
C) bluer and rounder. 
D) bluer and flattened. 
E) always much smaller. 
A) redder and rounder. 
B) redder and flattened. 
C) bluer and rounder. 
D) bluer and flattened. 
E) always much smaller.

Question 7

What does cosmological redshift do to light?

Accepted Answer

A) makes it brighter 
B) stretches its wavelength 
C) makes it slow down 
D) makes all light infrared 
A) makes it brighter 
B) stretches its wavelength 
C) makes it slow down 
D) makes all light infrared

Question 8

Process of Science: Most galaxies do not obey Hubble's Law perfectly.Why do we not take this as evidence that Hubble's law (and the theory of the expanding universe)is incorrect?

Accepted Answer

Hubble's law describes motions due only

Question 9

The lookback time of the cosmological horizon is

Accepted Answer

A) the Big Bang. 
B) the age of the universe. 
C) 1 billion years. 
D) 10 billion years. 
A) the Big Bang. 
B) the age of the universe. 
C) 1 billion years. 
D) 10 billion years.

Question 10

Which of the following types of galaxies are most spherical in shape?

Accepted Answer

A) spirals 
B) ellipticals 
C) lenticulars 
D) irregulars 
A) spirals 
B) ellipticals 
C) lenticulars 
D) irregulars

Question 11

Approximately how many stars does a dwarf elliptical galaxy have?

Accepted Answer

A) 1 trillion 
B) 100 billion 
C) 10 billion 
D) less than a billion 
E) less than a million 
A) 1 trillion 
B) 100 billion 
C) 10 billion 
D) less than a billion 
E) less than a million

Question 12

Suppose an elliptical galaxy is so far away that we cannot see even its brightest stars individually.Which of the following techniques might allow us to measure its distance?

Accepted Answer

A) We could use parallax. 
B) We could use Cepheid variables as standard candles. 
C) We could use a white dwarf supernova as a standard candle. 
D) We could use radar ranging. 
A) We could use parallax. 
B) We could use Cepheid variables as standard candles. 
C) We could use a white dwarf supernova as a standard candle. 
D) We could use radar ranging.

Question 13

When we use an analogy that represents the expanding universe with the surface of an expanding balloon,what does the inside of the balloon represent?

Accepted Answer

A) It represents the center of the universe. 
B) It represents the entire universe. 
C) It represents regions of the universe beyond the Milky Way Galaxy. 
D) The inside of the balloon does not represent any part of our universe. 
A) It represents the center of the universe. 
B) It represents the entire universe. 
C) It represents regions of the universe beyond the Milky Way Galaxy. 
D) The inside of the balloon does not represent any part of our universe.

Question 14

Hubble's galaxy classification diagram (the "tuning fork")

Accepted Answer

A) explains active galactic nuclei. 
B) shows how galaxies evolve from one form to another. 
C) suggests the existence of black holes. 
D) relates galaxies according to their shapes,but not according to any evolutionary status. 
A) explains active galactic nuclei. 
B) shows how galaxies evolve from one form to another. 
C) suggests the existence of black holes. 
D) relates galaxies according to their shapes,but not according to any evolutionary status.

Question 15

Which of the following sequences lists the methods for determining distance in the correct order from nearest to farthest?

Accepted Answer

A) parallax,Cepheid variables,Hubble's law 
B) parallax,Hubble's law,Cepheid variables 
C) parallax,white-dwarf supernovae,Hubble's law 
D) parallax,Hubble's law,white-dwarf supernovae 
A) parallax,Cepheid variables,Hubble's law 
B) parallax,Hubble's law,Cepheid variables 
C) parallax,white-dwarf supernovae,Hubble's law 
D) parallax,Hubble's law,white-dwarf supernovae

Question 16

You observe the peak brightnesses of two white dwarf supernovae.Supernova A is only 1/4 as bright as Supernova B.What can you say about their relative distances?

Accepted Answer

A) Supernova A is twice as far away as Supernova B. 
B) Supernova A is 4 times as far away as Supernova B. 
C) Supernova B is 4 times as far away as Supernova A. 
D) Supernova B is twice as far away as Supernova A. 
E) We can't say anything about their relative distances because we do not have enough information. 
A) Supernova A is twice as far away as Supernova B. 
B) Supernova A is 4 times as far away as Supernova B. 
C) Supernova B is 4 times as far away as Supernova A. 
D) Supernova B is twice as far away as Supernova A. 
E) We can't say anything about their relative distances because we do not have enough information.

Question 17

In 1924,Edwin Hubble proved that the Andromeda Galaxy lay far beyond the bounds of the Milky Way,thus putting to rest the idea that it might have been a cloud within our own galaxy.How was he able to prove this?

Accepted Answer

A) He proved this by observing individual Cepheid variable stars in Andromeda and applying the period-luminosity relation. 
B) He was able to measure the parallax of the Andromeda Galaxy. 
C) He found that the universe is expanding,and therefore concluded that Andromeda must lie outside our own galaxy. 
D) He was the first person ever to look through a telescope at the object we now call the Andromeda Galaxy. 
A) He proved this by observing individual Cepheid variable stars in Andromeda and applying the period-luminosity relation. 
B) He was able to measure the parallax of the Andromeda Galaxy. 
C) He found that the universe is expanding,and therefore concluded that Andromeda must lie outside our own galaxy. 
D) He was the first person ever to look through a telescope at the object we now call the Andromeda Galaxy.

Question 18

What is a standard candle?

Accepted Answer

A) an object for which we are likely to know the true luminosity 
B) an object for which we can easily measure the apparent brightness 
C) a class of objects in astronomy that all have exactly the same luminosity 
D) any star for which we know the exact apparent brightness 
E) a long,tapered candle that lights easily 
A) an object for which we are likely to know the true luminosity 
B) an object for which we can easily measure the apparent brightness 
C) a class of objects in astronomy that all have exactly the same luminosity 
D) any star for which we know the exact apparent brightness 
E) a long,tapered candle that lights easily

Question 19

Based on counting the number of galaxies in a small patch of the sky and multiplying by the number of such patches needed to cover the entire sky,the total number of galaxies in the observable universe is estimated to be approximately

Accepted Answer

A) 100 million. 
B) 1 billion. 
C) 10 billion. 
D) 100 billion. 
E) 1 trillion. 
A) 100 million. 
B) 1 billion. 
C) 10 billion. 
D) 100 billion. 
E) 1 trillion.

Question 20

What does the equivalent of an H-R diagram for galaxies,plotting luminosity versus color,show?

Accepted Answer

A) galaxies fill the diagram showing that there is no correlation between luminosity and color 
B) two clumps,one blue with relatively low luminosity,one red with relatively high luminosity,and a valley in between with few galaxies 
C) a continuum from faint,blue galaxies to bright,red galaxies 
D) a continuum from faint,red galaxies to bright,blue galaxies 
E) a main sequence,just as for stars 
A) galaxies fill the diagram showing that there is no correlation between luminosity and color 
B) two clumps,one blue with relatively low luminosity,one red with relatively high luminosity,and a valley in between with few galaxies 
C) a continuum from faint,blue galaxies to bright,red galaxies 
D) a continuum from faint,red galaxies to bright,blue galaxies 
E) a main sequence,just as for stars

Exam 20: Galaxies and the Foundations of Modern Cosmology

How does a lenticular galaxy differ from a normal spiral galaxy?

What is the most accurate way to determine the distance to a very distant irregular galaxy?

What two observable properties of a Cepheid variable are directly related to one another?

Suppose that we look at a photograph of many galaxies.Assuming that all galaxies formed at about the same time,which galaxy in the picture is the youngest?

All galaxies start out as members of the blue cloud,but some transition to the red sequence.

Compared to spiral galaxies,elliptical galaxies are

What does cosmological redshift do to light?

Process of Science: Most galaxies do not obey Hubble's Law perfectly.Why do we not take this as evidence that Hubble's law (and the theory of the expanding universe)is incorrect?

The lookback time of the cosmological horizon is

Which of the following types of galaxies are most spherical in shape?

Approximately how many stars does a dwarf elliptical galaxy have?

Suppose an elliptical galaxy is so far away that we cannot see even its brightest stars individually.Which of the following techniques might allow us to measure its distance?

When we use an analogy that represents the expanding universe with the surface of an expanding balloon,what does the inside of the balloon represent?

Hubble's galaxy classification diagram (the "tuning fork")

Which of the following sequences lists the methods for determining distance in the correct order from nearest to farthest?

You observe the peak brightnesses of two white dwarf supernovae.Supernova A is only 1/4 as bright as Supernova B.What can you say about their relative distances?

In 1924,Edwin Hubble proved that the Andromeda Galaxy lay far beyond the bounds of the Milky Way,thus putting to rest the idea that it might have been a cloud within our own galaxy.How was he able to prove this?

What is a standard candle?

Based on counting the number of galaxies in a small patch of the sky and multiplying by the number of such patches needed to cover the entire sky,the total number of galaxies in the observable universe is estimated to be approximately

What does the equivalent of an H-R diagram for galaxies,plotting luminosity versus color,show?

A Modern View of the Universe

Discovering the Universe for Yourself

The Science of Astronomy

Making Sense of the Universe: Understanding Motion, Energy, and Gravity

Light and Matter: Reading Messages from the Cosmos

Telescopes: Portals of Discovery

Our Planetary System

Formation of the Solar System

Planetary Geology: Earth and the Other Terrestrial Worlds

Planetary Atmospheres: Earth and the Other Terrestrial Worlds

Jovian Planet Systems

Asteroids, Comets, and Dwarf Planets: Their Nature, Orbits, and Impacts

Other Planetary Systems: The New Science of Distant Worlds

Our Star

Surveying the Stars

Star Birth

Star Stuff

The Bizarre Stellar Graveyard

Our Galaxy

Galaxy Evolution

The Birth of the Universe

Dark Matter, Dark Energy, and the Fate of the Universe

Life in the Universe

Celestial Timekeeping and Navigation

Space and Time

Spacetime and Gravity

Building Blocks of the Universe

Filters