Question 1

In the Milky Way halo,the stars orbit

Accepted Answer

A)  mostly in the prograde direction. 
B)  mostly in the retrograde direction. 
C)  equally in the prograde and retrograde directions. 
D)  neither in the prograde nor retrograde directions. 
A)  mostly in the prograde direction. 
B)  mostly in the retrograde direction. 
C)  equally in the prograde and retrograde directions. 
D)  neither in the prograde nor retrograde directions.

Question 2

The Milky Way appears as __________ in the night sky because __________.

Accepted Answer

A)  randomly distributed stars;the Sun lies near the center of the Milky Way 
B)  a faint band of light sprinkled with dark clouds;the Sun lies in the disk 
C)  a faint band of light;the Sun lies in the halo 
D)  an ellipse of light in the Southern sky;the Sun lies midway along the disk 
A)  randomly distributed stars;the Sun lies near the center of the Milky Way 
B)  a faint band of light sprinkled with dark clouds;the Sun lies in the disk 
C)  a faint band of light;the Sun lies in the halo 
D)  an ellipse of light in the Southern sky;the Sun lies midway along the disk

Question 3

Cosmic rays come mostly from extragalactic sources and contribute little to the overall energy balance in the Milky Way disk.

Accepted Answer

A) True 
 B)False

Question 4

The chemical composition of a star's atmosphere tells us

Accepted Answer

A)  how much nuclear burning has gone on in the star. 
B)  the star's evolutionary stage. 
C)  the chemical composition of the cloud from which the star formed. 
D)  All of the above 
A)  how much nuclear burning has gone on in the star. 
B)  the star's evolutionary stage. 
C)  the chemical composition of the cloud from which the star formed. 
D)  All of the above

Question 5

What is the radius of the event horizon for the   black hole at the center of the Milky Way?

Accepted Answer

A)  0.02 AU 
B)  0.08 AU 
C)  0.17 AU 
D)  0.35 AU 
A)  0.02 AU 
B)  0.08 AU 
C)  0.17 AU 
D)  0.35 AU

Question 6

If a globular cluster were 1,000 light-years away from us and an RR Lyrae star in it had an absolute magnitude of 0.6,what would its apparent magnitude be?

Accepted Answer

A)  8 
B)  10 
C)  12 
D)  14 
A)  8 
B)  10 
C)  12 
D)  14

Question 7

How have astronomers searched for evidence of MACHOs in the halo of the Milky Way?

Accepted Answer

A)  They search for stars that are binary companions of MACHOs. 
B)  They search for rapidly moving,massive gas clouds. 
C)  They search for disturbances in the background of gravitational waves. 
D)  They search for stars whose light is briefly amplified by gravitational lensing. 
A)  They search for stars that are binary companions of MACHOs. 
B)  They search for rapidly moving,massive gas clouds. 
C)  They search for disturbances in the background of gravitational waves. 
D)  They search for stars whose light is briefly amplified by gravitational lensing.

Question 8

Where would we find the stars with the richest abundance of massive elements? Where would we find those with the smallest amounts of massive elements? Why?

Accepted Answer

Stars with the highest abundance of mass

Question 9

Open star clusters primarily inhabit which part of spiral galaxies?

Accepted Answer

A)  Disk 
B)  Halo 
C)  Bulge 
D)  Nucleus 
A)  Disk 
B)  Halo 
C)  Bulge 
D)  Nucleus

Question 10

Stars in the halo are most easily identified passing by the Sun because of their distinctively redder colors.

Accepted Answer

A) True 
 B)False

Question 11

The Sun is located approximately

Accepted Answer

A)  halfway out in the disk. 
B)  one-third of the way out in the halo. 
C)  one-quarter of the way out in the bulge. 
D)  three-quarters of the way out in the disk. 
A)  halfway out in the disk. 
B)  one-third of the way out in the halo. 
C)  one-quarter of the way out in the bulge. 
D)  three-quarters of the way out in the disk.

Question 12

In which part of the Milky Way would you find little or no neutral hydrogen,no current star formation,and stars that are older than 10 billion years?

Accepted Answer

A)  The halo 
B)  The disk 
C)  The galactic center 
D)  The solar neighborhood 
A)  The halo 
B)  The disk 
C)  The galactic center 
D)  The solar neighborhood

Question 13

Explain how a standard candle allows you to determine the distance to an object.What is it that you have to measure or know about the standard candle to derive its distance?

Accepted Answer

A standard candle is a star that can be

Question 14

The Milky Way has two major spiral arms that emanate from the ends of its bar.

Accepted Answer

A) True 
 B)False

Question 15

If we found gas at the edge of the disk of the Milky Way at a distance of 50,000 light-years from the center,which rotated in a circular orbit with a velocity of 300 km/s,what would be the total mass enclosed within this radius?

Accepted Answer

A)    
B)    
C)    
D)    
A)    
B)    
C)    
D)

Question 16

Sagittarius A*,the radio source located at the center of our galaxy,is believed to be

Accepted Answer

A)  a massive star cluster. 
B)  a supernova remnant. 
C)  a quasar. 
D)  a supermassive black hole. 
A)  a massive star cluster. 
B)  a supernova remnant. 
C)  a quasar. 
D)  a supermassive black hole.

Question 17

How have astronomers measured the mass of the black hole at the center of our galaxy?

Accepted Answer

A)  Using the rotation curve derived from 21-cm emission 
B)  By observing the motions of stars near the center of the galaxy 
C)  By measuring the brightness of the quasar 
D)  By measuring the Doppler shift of Sagittarius A* 
A)  Using the rotation curve derived from 21-cm emission 
B)  By observing the motions of stars near the center of the galaxy 
C)  By measuring the brightness of the quasar 
D)  By measuring the Doppler shift of Sagittarius A*

Question 18

Why is 21-cm radiation the best way to map the spiral arms in the Milky Way?

Accepted Answer

A)  The molecular hydrogen gas that produces this emission is concentrated in the spiral arms. 
B)  These photons,which are produced by neutral hydrogen,penetrate the dense clouds of gas and dust in the disk. 
C)  This synchrotron emission is produced by supernovae,which are concentrated in the spiral arms. 
D)  Radio telescopes are easier to operate than optical telescopes and observations can be made even during the daytime. 
A)  The molecular hydrogen gas that produces this emission is concentrated in the spiral arms. 
B)  These photons,which are produced by neutral hydrogen,penetrate the dense clouds of gas and dust in the disk. 
C)  This synchrotron emission is produced by supernovae,which are concentrated in the spiral arms. 
D)  Radio telescopes are easier to operate than optical telescopes and observations can be made even during the daytime.

Question 19

Every open star cluster in the Milky Way is younger than even the youngest globular cluster.

Accepted Answer

A) True 
 B)False

Question 20

Because of the ages of globular clusters in the Milky Way,we think our galaxy's early formation history was characterized by

Accepted Answer

A)  one single cloud of gas gently collapsing and star formation proceeding slowly within it. 
B)  one single cloud of gas that rapidly collapsed and turned most of its gas into stars. 
C)  violent merging of protogalactic fragments that stimulated a high rate of star formation. 
D)  slow merging of protogalactic fragments after they had already turned most of their gas into stars. 
A)  one single cloud of gas gently collapsing and star formation proceeding slowly within it. 
B)  one single cloud of gas that rapidly collapsed and turned most of its gas into stars. 
C)  violent merging of protogalactic fragments that stimulated a high rate of star formation. 
D)  slow merging of protogalactic fragments after they had already turned most of their gas into stars.

Exam 20: The Milky Waya Normal Spiral Galaxy

In the Milky Way halo,the stars orbit

The Milky Way appears as __________ in the night sky because __________.

Cosmic rays come mostly from extragalactic sources and contribute little to the overall energy balance in the Milky Way disk.

The chemical composition of a star's atmosphere tells us

What is the radius of the event horizon for the black hole at the center of the Milky Way?

If a globular cluster were 1,000 light-years away from us and an RR Lyrae star in it had an absolute magnitude of 0.6,what would its apparent magnitude be?

How have astronomers searched for evidence of MACHOs in the halo of the Milky Way?

Where would we find the stars with the richest abundance of massive elements? Where would we find those with the smallest amounts of massive elements? Why?

Open star clusters primarily inhabit which part of spiral galaxies?

Stars in the halo are most easily identified passing by the Sun because of their distinctively redder colors.

The Sun is located approximately

In which part of the Milky Way would you find little or no neutral hydrogen,no current star formation,and stars that are older than 10 billion years?

Explain how a standard candle allows you to determine the distance to an object.What is it that you have to measure or know about the standard candle to derive its distance?

The Milky Way has two major spiral arms that emanate from the ends of its bar.

If we found gas at the edge of the disk of the Milky Way at a distance of 50,000 light-years from the center,which rotated in a circular orbit with a velocity of 300 km/s,what would be the total mass enclosed within this radius?

Sagittarius A*,the radio source located at the center of our galaxy,is believed to be

How have astronomers measured the mass of the black hole at the center of our galaxy?

Why is 21-cm radiation the best way to map the spiral arms in the Milky Way?

Every open star cluster in the Milky Way is younger than even the youngest globular cluster.

Because of the ages of globular clusters in the Milky Way,we think our galaxy's early formation history was characterized by

Why Learn Astronomy

Patterns in the Skymotions of Earth

Gravity and Orbitsa Celestial Ballet

Light

The Tools of the Astronomer

The Birth and Evolution of Planetary Systems

The Terrestrial Planets and Earths Moon

Atmospheres of the Terrestrial Planets

Worlds of Gas and Liquidthe Giant Planets

Gravity Is More Than Keplers Laws

Planetary Adornmentsmoons and Rings

Dwarf Planets and Small Solar System Bodies

Taking the Measure of Stars

A Run-Of-The-Mill G-Type Starour Sun

Star Formation and the Interstellar Medium

Stars in the Slow Lanelow-Mass Stellar Evolution

Live Fast,die Younghigh-Mass Stellar Evolution

Our Expanding Universe

Galaxies

Modern Cosmology

The Origin of Structure

Life

Filters

The Milky Way appears as in the night sky because .