Question 1

What is the major difference between an elliptical galaxy and a spiral galaxy?

Accepted Answer

A) A spiral galaxy contains mostly younger stars. 
B) A spiral galaxy has a spherical halo. 
C) An elliptical galaxy lacks a disk component. 
D) Elliptical galaxies are not as big as spiral galaxies. 
E) There are no dwarf spiral galaxies,but there are dwarf ellipticals. 
A) A spiral galaxy contains mostly younger stars. 
B) A spiral galaxy has a spherical halo. 
C) An elliptical galaxy lacks a disk component. 
D) Elliptical galaxies are not as big as spiral galaxies. 
E) There are no dwarf spiral galaxies,but there are dwarf ellipticals.

Question 2

Which types of galaxies have a clearly defined disk component?

Accepted Answer

A) spirals only 
B) ellipticals only 
C) lenticulars only 
D) irregulars only 
E) spirals and lenticulars 
A) spirals only 
B) ellipticals only 
C) lenticulars only 
D) irregulars only 
E) spirals and lenticulars

Question 3

White-dwarf supernovae are good standard candles for distance measurements for all the following reasons except which?

Accepted Answer

A) All white-dwarf supernovae involve the explosion of stars of nearly the same mass. 
B) White-dwarf supernovae are so bright that they can be detected even in very distant galaxies. 
C) White-dwarf supernovae are common enough that we detect several every year. 
D) White-dwarf supernovae occur only among young and extremely bright stars. 
E) All white-dwarf supernovae have similar light curves,which makes them easy to distinguish from massive-star supernovae. 
A) All white-dwarf supernovae involve the explosion of stars of nearly the same mass. 
B) White-dwarf supernovae are so bright that they can be detected even in very distant galaxies. 
C) White-dwarf supernovae are common enough that we detect several every year. 
D) White-dwarf supernovae occur only among young and extremely bright stars. 
E) All white-dwarf supernovae have similar light curves,which makes them easy to distinguish from massive-star supernovae.

Question 4

Process of Science: Give examples of how we build upon our knowledge of stars to measure distances to the edge of the Universe.

Accepted Answer

We use established theories fo

Question 5

Which types of galaxies have a clearly defined halo component?

Accepted Answer

A) spirals only 
B) ellipticals only 
C) lenticulars only 
D) irregulars only 
E) all but irregulars 
A) spirals only 
B) ellipticals only 
C) lenticulars only 
D) irregulars only 
E) all but irregulars

Question 6

Given that white dwarf supernovae are such good standard candles,why don't we use them to measure the distance to all galaxies?

Accepted Answer

A) They are rare events,so we have observed them in only a tiny fraction of all galaxies. 
B) We cannot see them beyond a distance of about 100 million light-years. 
C) They can occur only in spiral galaxies,not elliptical galaxies. 
D) We would,but we don't have enough telescopes. 
A) They are rare events,so we have observed them in only a tiny fraction of all galaxies. 
B) We cannot see them beyond a distance of about 100 million light-years. 
C) They can occur only in spiral galaxies,not elliptical galaxies. 
D) We would,but we don't have enough telescopes.

Question 7

Stars are continually forming in the halo of our Galaxy today.

Accepted Answer

A) True 
 B)False

Question 8

The fact that the universe is expanding means that space itself is growing within

Accepted Answer

A) the Milky Way. 
B) clusters of galaxies. 
C) the observable universe. 
D) the Local Group. 
A) the Milky Way. 
B) clusters of galaxies. 
C) the observable universe. 
D) the Local Group.

Question 9

In a photo like the Hubble Deep Field (Figure 20.1 in your textbook),we see galaxies in many different stages of their lives.In general,which galaxies are seen in the earliest (youngest)stages of their lives?

Accepted Answer

A) the galaxies that are farthest away 
B) the galaxies that have the most hot,young O and B stars 
C) the galaxies that are the reddest in color 
D) the galaxies that are nearest to us 
A) the galaxies that are farthest away 
B) the galaxies that have the most hot,young O and B stars 
C) the galaxies that are the reddest in color 
D) the galaxies that are nearest to us

Question 10

Which of the following is a consequence of Hubble's Law?

Accepted Answer

A) the Big Bang 
B) all galaxies are moving away from us equally fast 
C) the more distant a galaxy is from us,the faster it moves away from us 
D) the closer a galaxy is to us,the faster it moves away from us 
E) more distant galaxies appear younger 
A) the Big Bang 
B) all galaxies are moving away from us equally fast 
C) the more distant a galaxy is from us,the faster it moves away from us 
D) the closer a galaxy is to us,the faster it moves away from us 
E) more distant galaxies appear younger

Question 11

What is the primary practical difficulty that limits the use of Hubble's law for measuring distances?

Accepted Answer

A) Redshifts of galaxies are difficult to measure. 
B) The recession velocities of distant galaxies are so great that they are hard to measure. 
C) We do not know Hubble's constant very accurately yet. 
D) Hubble's law is only useful theoretically;it is difficult to use in practice. 
E) The motion of Earth relative to the Milky Way is difficult to account for. 
A) Redshifts of galaxies are difficult to measure. 
B) The recession velocities of distant galaxies are so great that they are hard to measure. 
C) We do not know Hubble's constant very accurately yet. 
D) Hubble's law is only useful theoretically;it is difficult to use in practice. 
E) The motion of Earth relative to the Milky Way is difficult to account for.

Question 12

What two quantities did Edwin Hubble plot against each other to discover the expansion of the Universe?

Accepted Answer

A) velocity and distance 
B) luminosity and distance 
C) velocity and temperature 
D) luminosity and temperature 
E) age and distance 
A) velocity and distance 
B) luminosity and distance 
C) velocity and temperature 
D) luminosity and temperature 
E) age and distance

Question 13

If we went back in time 10 billion years,would we expect Hubble's constant to be identical to the present-day Hubble constant?

Accepted Answer

A) Yes,a constant never changes. 
B) No,Hubble's constant is roughly equal to 1 divided by the age of the universe,and 10 billion is a substantial enough number to notice a difference. 
C) If we went back further in time,it would be different,but 10 billion years is not enough. 
D) It would only change if we went 10 billion years into the future. 
A) Yes,a constant never changes. 
B) No,Hubble's constant is roughly equal to 1 divided by the age of the universe,and 10 billion is a substantial enough number to notice a difference. 
C) If we went back further in time,it would be different,but 10 billion years is not enough. 
D) It would only change if we went 10 billion years into the future.

Question 14

Spiral galaxies have more gas,dust,and younger stars than elliptical galaxies do.

Accepted Answer

A) True 
 B)False

Question 15

Does Hubble's law work well for galaxies in the Local Group? Why or why not?

Accepted Answer

A) No,because Hubble did not know the Local Group existed when he discovered his law. 
B) No,because galaxies in the Local Group are gravitationally bound together. 
C) No,because we do not know the precise value of Hubble's constant. 
D) Yes,it works so well that we have never detected any measurable deviations from its predictions. 
A) No,because Hubble did not know the Local Group existed when he discovered his law. 
B) No,because galaxies in the Local Group are gravitationally bound together. 
C) No,because we do not know the precise value of Hubble's constant. 
D) Yes,it works so well that we have never detected any measurable deviations from its predictions.

Question 16

A lenticular galaxy is another name for an elongated elliptical galaxy.

Accepted Answer

A) True 
 B)False

Exam 20: Galaxies and the Foundations of Modern Cosmology

What is the major difference between an elliptical galaxy and a spiral galaxy?

Which types of galaxies have a clearly defined disk component?

White-dwarf supernovae are good standard candles for distance measurements for all the following reasons except which?

Process of Science: Give examples of how we build upon our knowledge of stars to measure distances to the edge of the Universe.

Which types of galaxies have a clearly defined halo component?

Given that white dwarf supernovae are such good standard candles,why don't we use them to measure the distance to all galaxies?

Stars are continually forming in the halo of our Galaxy today.

The fact that the universe is expanding means that space itself is growing within

In a photo like the Hubble Deep Field (Figure 20.1 in your textbook),we see galaxies in many different stages of their lives.In general,which galaxies are seen in the earliest (youngest)stages of their lives?

Which of the following is a consequence of Hubble's Law?

What is the primary practical difficulty that limits the use of Hubble's law for measuring distances?

What two quantities did Edwin Hubble plot against each other to discover the expansion of the Universe?

If we went back in time 10 billion years,would we expect Hubble's constant to be identical to the present-day Hubble constant?

Spiral galaxies have more gas,dust,and younger stars than elliptical galaxies do.

Does Hubble's law work well for galaxies in the Local Group? Why or why not?

A lenticular galaxy is another name for an elongated elliptical galaxy.

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