Question 1

Which of the following best describes the Milky Way Galaxy?

Accepted Answer

A) a barred spiral galaxy with a disk about 100,000 light-years in diameter and containing between 100 billion and 1 trillion stars 
B) a barred spiral galaxy with a disk about 1 billion kilometers in diameter and containing between 100 million and 1 billion stars 
C) a barred spiral galaxy with a disk about 100,000 light-years in diameter and containing about 100,000 stars 
D) a spherically shaped collection of stars including our solar system and about a dozen other solar systems,stretching about 4 light-years in diameter 
E) a spherically shaped collection of about 1 million stars that is about 100 light-years in diameter 
A) a barred spiral galaxy with a disk about 100,000 light-years in diameter and containing between 100 billion and 1 trillion stars 
B) a barred spiral galaxy with a disk about 1 billion kilometers in diameter and containing between 100 million and 1 billion stars 
C) a barred spiral galaxy with a disk about 100,000 light-years in diameter and containing about 100,000 stars 
D) a spherically shaped collection of stars including our solar system and about a dozen other solar systems,stretching about 4 light-years in diameter 
E) a spherically shaped collection of about 1 million stars that is about 100 light-years in diameter A

Question 2

A typical supercluster contains no more than about 10,000 stars.

Accepted Answer

A) True 
 B)False  False

Question 3

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

Question 4

No galaxies existed before the Big Bang.

Accepted Answer

A) True 
 B)False

Question 5

The speed of light is 300,000 km/s.How far is a light-year? Be sure to show all work clearly on your calculations.

Accepted Answer

1 light-year
= (spee

Question 6

About where is our solar system located within the Milky Way Galaxy?

Accepted Answer

A) at the center of the galaxy 
B) about 10 percent of the way from the center of the galaxy to the outskirts of the galactic disk 
C) about half way from the center of the galaxy to the outskirts of the galactic disk 
D) near the far outskirts of the galactic disk 
E) in the halo of the galaxy above the galactic disk 
A) at the center of the galaxy 
B) about 10 percent of the way from the center of the galaxy to the outskirts of the galactic disk 
C) about half way from the center of the galaxy to the outskirts of the galactic disk 
D) near the far outskirts of the galactic disk 
E) in the halo of the galaxy above the galactic disk

Question 7

One light-hour is the distance that light travels in an hour.How far is this,in kilometers? (Recall that the speed of light is 300,000 km/s. )

Accepted Answer

A) 300,000 km 
B) 18 million km 
C) 100 million km 
D) 1.08 billion km 
E) 9.46 trillion km 
A) 300,000 km 
B) 18 million km 
C) 100 million km 
D) 1.08 billion km 
E) 9.46 trillion km

Question 8

Which of the following is smallest?

Accepted Answer

A) size of a typical planet 
B) 1 light-second 
C) 1 AU 
D) size of a typical star 
A) size of a typical planet 
B) 1 light-second 
C) 1 AU 
D) size of a typical star

Question 9

If you could count stars at a rate of about one per second,how long would it take to count all the stars in the Milky Way Galaxy?

Accepted Answer

A) several days 
B) several weeks 
C) several years 
D) several thousand years 
A) several days 
B) several weeks 
C) several years 
D) several thousand years

Question 10

Modern telescopes are capable of seeing bright galaxies up to about

Accepted Answer

A) 1 million light-years away. 
B) 10 million light-years away. 
C) 1 billion light-years away. 
D) 10 billion light-years away. 
E) 1 trillion light-years away. 
A) 1 million light-years away. 
B) 10 million light-years away. 
C) 1 billion light-years away. 
D) 10 billion light-years away. 
E) 1 trillion light-years away.

Question 11

A typical galaxy is a

Accepted Answer

A) collection of a few hundred million to a trillion or more stars,bound together by gravity. 
B) large,glowing ball of gas powered by nuclear energy. 
C) nearby object orbiting a planet. 
D) relatively small,icy object orbiting a star. 
A) collection of a few hundred million to a trillion or more stars,bound together by gravity. 
B) large,glowing ball of gas powered by nuclear energy. 
C) nearby object orbiting a planet. 
D) relatively small,icy object orbiting a star.

Question 12

What do we mean when we say that the universe is expanding?

Accepted Answer

A) Average distances are increasing between star systems within galaxies. 
B) Everything in the universe is gradually growing in size. 
C) All galaxies are increasingly moving away from one another. 
D) The statement is not meant to be literal;rather,it means that our knowledge of the universe is growing. 
E) Individual galaxies are gradually growing in size. 
A) Average distances are increasing between star systems within galaxies. 
B) Everything in the universe is gradually growing in size. 
C) All galaxies are increasingly moving away from one another. 
D) The statement is not meant to be literal;rather,it means that our knowledge of the universe is growing. 
E) Individual galaxies are gradually growing in size.

Question 13

Patterns of stars in constellations hardly change in appearance over times of even a few thousand years.Why?

Accepted Answer

A) Stars are fixed and never move. 
B) Stars move,but they move very slowly-only a few kilometers in a thousand years. 
C) Although most stars move through the sky,the brightest stars do not,and these are the ones that trace the patterns we see in the constellations. 
D) The stars in our sky actually move rapidly relative to us-thousands of kilometers per hour-but are so far away that it takes a long time for this motion to make a noticeable change in the patterns in the sky. 
E) Stars within a constellation move together as a group,which tends to hide their actual motion and prevent the pattern from changing. 
A) Stars are fixed and never move. 
B) Stars move,but they move very slowly-only a few kilometers in a thousand years. 
C) Although most stars move through the sky,the brightest stars do not,and these are the ones that trace the patterns we see in the constellations. 
D) The stars in our sky actually move rapidly relative to us-thousands of kilometers per hour-but are so far away that it takes a long time for this motion to make a noticeable change in the patterns in the sky. 
E) Stars within a constellation move together as a group,which tends to hide their actual motion and prevent the pattern from changing.

Question 14

Suppose we look at two distant galaxies: Galaxy 1 is twice as far away as Galaxy 2.In this case,

Accepted Answer

A) Galaxy 1 must be twice as big as Galaxy 2. 
B) we are seeing Galaxy 1 as it looked at an earlier time in the history of the universe than Galaxy 2. 
C) we are seeing Galaxy 1 as it looked at a later time in the history of the universe than Galaxy 2. 
D) Galaxy 2 must be twice as old as Galaxy 1. 
A) Galaxy 1 must be twice as big as Galaxy 2. 
B) we are seeing Galaxy 1 as it looked at an earlier time in the history of the universe than Galaxy 2. 
C) we are seeing Galaxy 1 as it looked at a later time in the history of the universe than Galaxy 2. 
D) Galaxy 2 must be twice as old as Galaxy 1.

Question 15

Based on the idea of "spaceship Earth," write one or two paragraphs explaining why it is not the case that we are "just sitting here."

Accepted Answer

Far from just sitting still,we on Earth

Question 16

Briefly explain how the Sun generates energy.

Accepted Answer

The Sun generates energy throu

Question 17

If we use 1 millimeter to represent 1 light-year,how large in diameter is the Milky Way Galaxy?

Accepted Answer

A) 100 millimeters 
B) 100 meters 
C) 1 kilometer 
D) 100 kilometers 
E) 1 million millimeters 
A) 100 millimeters 
B) 100 meters 
C) 1 kilometer 
D) 100 kilometers 
E) 1 million millimeters

Question 18

Consider the following statement,and explain whether or not it is sensible: Someday we may build spaceships capable of traveling at a speed of 1 light-second per hour.

Accepted Answer

This statement is fine.A light

Question 19

Consider the following statement,and explain whether or not it is sensible: Earth is always precisely 1 AU from the Sun.

Accepted Answer

Not sensible: One AU

Question 20

Earth is always precisely 1 AU from the Sun.

Accepted Answer

A) True 
 B)False

Exam 1: A Modern View of the Universe

Which of the following best describes the Milky Way Galaxy?

A typical supercluster contains no more than about 10,000 stars.

Suppose 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?

No galaxies existed before the Big Bang.

The speed of light is 300,000 km/s.How far is a light-year? Be sure to show all work clearly on your calculations.

About where is our solar system located within the Milky Way Galaxy?

One light-hour is the distance that light travels in an hour.How far is this,in kilometers? (Recall that the speed of light is 300,000 km/s. )

Which of the following is smallest?

If you could count stars at a rate of about one per second,how long would it take to count all the stars in the Milky Way Galaxy?

Modern telescopes are capable of seeing bright galaxies up to about

A typical galaxy is a

What do we mean when we say that the universe is expanding?

Patterns of stars in constellations hardly change in appearance over times of even a few thousand years.Why?

Suppose we look at two distant galaxies: Galaxy 1 is twice as far away as Galaxy 2.In this case,

Based on the idea of "spaceship Earth," write one or two paragraphs explaining why it is not the case that we are "just sitting here."

Briefly explain how the Sun generates energy.

If we use 1 millimeter to represent 1 light-year,how large in diameter is the Milky Way Galaxy?

Consider the following statement,and explain whether or not it is sensible: Someday we may build spaceships capable of traveling at a speed of 1 light-second per hour.

Consider the following statement,and explain whether or not it is sensible: Earth is always precisely 1 AU from the Sun.

Earth is always precisely 1 AU from the Sun.

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

Galaxies and the Foundations of Modern Cosmology

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