Astronomy Chapter 1 Test Answers

which of the following statements does not use the term light-year in an appropriate way?
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The farthest bright galaxies that modern telescopes are capable of seeing are up to
A) 1 million light years away.
B) 10 million light years away.
C) 1 trillion light years away.
D) 1 billion light years away.
E) 10 billion light years away.
E
Suppose we imagine the Sun to be about the size of a grapefruit. How big an area would the orbits of the eight planets of the Solar System cover?
A) the size of a small city
B) the size of a western state (e.g., Colorado)
C) the size of a typical dorm room
D) the size of a typical campus building
E) the size of a typical campus
E
Earth is made mostly of metals and rocks. Where did this material come from?
A) It was made by nuclear fission of uranium and other radioactive materials.
B) It was created by chemical reactions in interstellar space.
C) It was produced in the Big Bang.
D) It was produced by nuclear fusion in stars.
E) It was made by our Sun.
D
What is nuclear fusion?
A) the process of splitting nuclei to produce energy
B) the process of turning matter into pure energy
C) an explosion caused by putting together two volatile chemicals
D) a process that only occurs in bombs
E) the process of combining lightweight nuclei to make heavier nuclei
E
Which of the following statements does not use the term light-year in an appropriate way?
A) A light-year is about 10 trillion kilometers.
B) It’s about 4 light-years from here to Alpha Centauri.
C) It will take the Voyager spacecraft about 20,000 years to travel just 1 light-year.
D) The Milky Way Galaxy is about 100,000 light-years in diameter.
E) It will take me light-years to complete this homework assignment.
E
Light takes approximately one second to travel from the Earth to the Moon. This means that the Moon is approximately
A) twice the distance from the Earth to the Sun.
B) 1 light year from the Earth.
C) 1 astronomical unit from the Earth.
D) 3,000 kilometers from the Earth.
E) 300,000 kilometers from the Earth.
D
One light-hour is the distance that light travels in an hour. How far is this, in kilometers? (Recall 7) that the speed of light is 300,000 km/s.)
A) 1.08 billion km
B) 9.46 trillion km
C) 100 million km
D) 300,000 km
E) 18 million km
A
Suppose we look at a photograph of many galaxies. Assuming that all galaxies formed at the same time after the Big Bang, which galaxy appears to us as the youngest?
A) the galaxy that is closest to us
B) the galaxy that appears bluest to us
C) the galaxy that appears largest to us
D) the galaxy that is furthest from us
E) All galaxies would appear to have the same age.
D
Suppose we imagine the Sun to be about the size of a grapefruit (about 10 cm across). Which of the following describes the size and distance of Earth on the same scale?
A) Earth is the size of a point about 1 meter away from the Sun.
B) Earth is the size of a point about 15 meters away from the Sun.
C) Earth is the size of a marble about 25 miles away from the Sun.
D) Earth is the size of a golf ball about 1 meter away from the Sun.
E) Earth is the size of a golf ball about 15 meters away from the Sun.
B
Which of the following correctly describes the concept of galactic recycling?
A) In the formation of a star, no matter is wasted as all excess material ends up recycled into
planets.
B) New stars are continuously being formed in the Milky Way out of gas that has been ejected from a previous generation of stars.
C) Stars near the center of the Milky Way are continually recycled to the outskirts of the disk by their orbital motion.
D) New galaxies are continuously being formed out of gas ejected from a previous generation of
galaxies.
E) Life is continuously being spread from star to star in the Milky Way.
B
What is the Sun mainly made of?
A) nearly equal portions of all the elements
B) oxygen and carbon
C) hydrogen and helium
D) carbon and nitrogen
E) hydrogen and oxygen
C
Which of the following is smallest?
A) 1 AU
B) Size of a typical star
C) 1 Light-Second
D) Size of a typical planet
D
Which of the following is largest?
A) distance to the nearest star (other than our Sun)
B) size of Pluto’s orbit
C) size of a typical galaxy
D) 1 light-year
C
On the 1-to-10-billion scale, about how far is it to the nearest stars besides the Sun?
A) 10,000 kilometers
B) 400 kilometers
C) 1,000 kilometers
D) 4,400 kilometers
E) 4 kilometers
D
Suppose we imagine the Sun to be about the size of a grapefruit (about 10 cm across). How far away are the nearest stars (the three stars of Alpha Centauri)?
A) the length of a football field
B) 2.5 miles
C) 2,500 miles
D) 25,000 miles
E) 250 miles
C
If we use 1 millimeter to represent 1 light-year, how large in diameter is the Milky Way Galaxy?
A) 100 millimeters
B) 100 meters
C) 100 kilometers
D) 1 kilometer
E) 1 million millimeters
B
Which of the following best describes the Milky Way Galaxy?
A) a spiral galaxy with a disk about 100,000 light-years in diameter and containing about 100,000 stars
B) a spiral galaxy with a disk about 100,000 light-years in diameter and containing between 100 billion and 1 trillion stars
C) a spiral galaxy with a disk about a billion kilometers in diameter and containing between 100 million and 1 billion 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
B
How many galaxies are there in the observable universe? A) about as many as the number of grains of sand on all the beaches on Earth
B) roughly (within a factor of the same as the number of stars in our galaxy
C) infinity
D) roughly a thousand times more than the number of stars in our galaxy
E) about as many as the number of stars we see in the sky with our naked eyes
B
On the scale of the cosmic calendar, in which the history of the universe is compressed to 1 year, how long has human civilization (i.e., since ancient Egypt) existed?
A) a few hours
B) less than a millionth of a second
C) about a month
D) a few seconds
E) about half the year
D
On a cosmic calendar, in which the history of the universe is compressed into 1 year, when did the dinosaurs become extinct?
A) in late October
B) in late August
C) in late November
D) in late September
E) in late December
E
On a cosmic calendar, in which the history of the universe is compressed into 1 year, when did Kepler and Galileo first discover that we live on a planet in a solar system?
A) 1 week ago
B) December 30
C) 1 day ago
D) 1 second ago
E) December 25
D
Approximately how fast is a person located at the Earth’s equator traveling due to the rotation of the Earth?
A) 170 km/hr
B) 17 km/hr
C) 17,000 km/hr
D) 1,700 km/hr
E) not moving at all
D
How long does it take our solar system to complete one orbit around the Milky Way Galaxy?
A) 1 million years
B) 230 million years
C) 100 million years
D) 230 thousand years
E) 10 thousand years
B
Which of the following statements about the Milky Way Galaxy is not true?
A) The galaxy is about 100,000 light-years in diameter.
B) One rotation of the galaxy takes about 200 million years.
C) Our solar system is located very close to the center of the Milky Way Galaxy.
D) It contains between 100 billion and 1 trillion stars.
C
Which of the following correctly lists speeds from slowest to fastest?
A) Earth’s speed of rotation on its axis, typical speeds of stars in the local solar neighborhood relative to us, Earth’s speed of revolution about the Sun, the speed of our solar system orbiting the center of the Milky Way Galaxy, the speeds of very distant galaxies relative to us
B) the speed of our solar system orbiting the center of the Milky Way Galaxy, Earth’s speed of revolution about the Sun, Earth’s speed of rotation on its axis, the speeds of very distant galaxies relative to us, typical speeds of stars in the local solar neighborhood relative to us
C) Earth’s speed of revolution about the Sun, typical speeds of stars in the local solar neighborhood relative to us, Earth’s speed of rotation on its axis, the speed of our solar system orbiting the center of the Milky Way Galaxy, the speeds of very distant galaxies relative to us
D) the speeds of very distant galaxies relative to us, typical speeds of stars in the local solar neighborhood relative to us, Earth’s speed of rotation on its axis, Earth’s speed of revolution about the Sun, the speed of our solar system orbiting the center of the Milky Way Galaxy
E) Earth’s speed of revolution about the Sun, Earth’s speed of rotation on its axis, the speed of our solar system orbiting the center of the Milky Way Galaxy, typical speeds of stars in the local solar neighborhood relative to us, the speeds of very distant galaxies relative to us
A
Most of the mass in the Milky Way Galaxy is located
A) in the halo (above/below the disk).
B) in the central bulge of the galaxy.
C) in the stars in the spiral arms.
D) in the gas and dust.
E) within the disk.
A
The distribution of the mass of the Milky Way Galaxy is determined by
A) studying how stars are distributed in the Milky Way.
B) studying the rotation of the galaxy.
C) counting the number of stars.
D) determining the amount of gas and dust.
E) weighing various parts of the Milky Way.
B
From the fact that virtually every galaxy is moving away from us and more distant galaxies are moving away from us at a faster rate than closer ones, we conclude that
A) the universe is shrinking.
B) the Milky Way Galaxy is expanding.
C) we are located at the center of the universe.
D) the farthest galaxies will eventually be moving faster than the speed of light.
E) the universe is expanding.
D
By studying distant galaxies in the 1920s, Hubble made the following important discovery that led us to conclude that the universe is expanding.
A) All galaxies outside the Local Group are moving away from us, and the farther away they are, the faster they’re going.
B) All galaxies contain billions of stars, and all galaxies have spiral shapes.
C) All galaxies outside the Local Group are orbiting the Local Group.
D) All galaxies outside the Local Group are moving away from us, and all are moving away at nearly the same speed.
E) All galaxies were born at the same time, and all will die at the same time.
A
Imagine that we put a raisin cake into the oven, with each raisin separated from the others by 1 cm. An hour later, we take it out and the distances between raisins are 3 cm. If you lived in one of the raisins and watched the other raisins as the cake expanded, which of the following would you conclude?
A) More distant raisins would be moving away from you faster.
B) All raisins would be moving away from you at the same speed.
C) More distant raisins would be moving away from you more slowly.
D) It depends: If you lived in a raisin near the left side of the cake, you’d see other raisins moving away from you, but they’d be coming toward you if you lived in a raisin near the right side of the cake.
A
How many seconds are in one year? (Calculate this, do not look it up.)
A) about 3,600 (3.6 × 103)
B) about 86 thousand (86,000, or 8.6 × 105)
C) about 30 million (30,000,000, or 3 × 107)
D) about 380 million (380,000,000, or 3.8 × 108)
C
The speed of light is about 300,000 km/s (3 × 105 km/s). How far does light travel in 30 seconds?
A) 900 thousand km (900,000, or 9 × 105 km)
B) 9 million km (9,000,000, or 9 × 106 km)
C) 10 thousand km (10,000, or 106 km)
D) 300 thousand km (300,000, or 3 × 105 km)
B
One light-minute is the distance light travels in one minute. The speed of light is about 300,000 33) km/s (3×105 km/s). How far is one light-minute?
A) 300 thousand km (300,000, or 3 × 105 km)
B) 1.08 billion km (1,080,000,000, or 1.08 × 109 km)
C) 18 million km (18,000,000, or 1.8 × 107 km)
D) 9.46 trillion km (9,460,000,000,000, or 9.46 × 1012 km)
C
One light-minute is the distance light travels in one minute. The speed of light is about 300,000 km/s (3 × 105 km/s). How far is 5 light- minutes?
A) 1.5 million km (1,500,000, or 1.5 × 10^6 km)
B) 47.3 trillion km (47,300,000,000,000, or 4.73 × 10^13 km)
C) 5.4 billion km (5,400,000,000, or 5.4 × 10^9 km)
D) 90 million km (90,000,000, or 9 × 10^7 k)
D
One light-hour is the distance light travels in one hour. The speed of light is about 300,000 km/s 35) (3 × 105 km/s). How far is 1 light-hour?
A) 9.46 trillion km (9,460,000,000,000, or 9.46 × 1012 km)
B) 300 thousand km (300,000, or 3 × 105 km)
C) 18 million km (18,000,000, or 1.8 × 107 km)
D) 1.08 billion km (1,080,000,000, or 1.08 ×109 km)
D
The planet Neptune is, on average, about 4.5 billion km from the sun. How long does it take light from the sun to reach Neptune? (Recall that the speed of light is about 300,000 km/s)
A) about 4 seconds
B) about 4 minutes
C) about 4 days
D) about 4 hours
D
One light-year is the distance light travels in one year. The speed of light is about 300,000 km/s 37) (3 × 105 km/s). How far is 1 light-year?
A) 300 thousand km (300,000, or 3 × 105 km)
B) 1.08 billion km (1,080,000,000, or 1.08 × 109 km)
C) 18 million km (18,000,000, or 1.8 × 107 km)
D) 9.46 trillion km (9,460,000,000,000, or 9.46 × 1012 km)
D
What is the diameter of the galaxy, in km?
A) About 100,000 (10^5)
B) About 1 million trillion km (10^18 km)
C) About 10 trillion km (10^13)
D) About 1 Billion Trillion km (10^21km)
D
If the entire galaxy (with a diameter of 100,000 light years) were represented by a circle with a 39) diameter of 4,400 km (similar to the width of the continental United States), then how far apart would be the Sun and its nearest stellar neighbor, Proxima Centauri (which is 4.2 light years
away)?
A) about 200 meters (about 2 football fields)
B) about 0.2 meters (about the length of an adult’s forearm)
C) about 2 meters (about 2 long footsteps)
D) about 20 meters (about the size of a large classroom)
A
The Earth has a radius of about 6,000 km. How long would it take for an object traveling at the speed of light to circle the earth? (Recall that the speed of light is 300,000 km/s)
A) 1/ 6000 of a second (0.00015 s)
B) 1/2 of a second (0.5 s)
C) 1/50 of a second (0.02s)
D) 1/300,000 of a second (0.0000033 s)
C
Our solar system is located about 27,000 light-years from the galactic center. How far does our solar system travel in one orbit?
A) 54,000 light-years
B) 100,000 light-years
C) 85,000 light-years
D) 170,000 light-years
D
Our solar system is located about 27,000 light-years from the galactic center. How far does our solar system travel in one orbit?
A) 8.5 × 1017 km
B) 1.7 × 1018 km
C) 1018 km
D) 5.4 × 1017 km
B
Stars nearby to our sun have an average relative speed of about 70,000 km/hour. How fast is that in km/s?
A) about 1200 km/s
B) about 4.2 million km/s
C) about 3000 km/s
D) about 20 km/s
D

What is the meaning of the word cosmos?

A) The origin of earth and life upon it
B) the light from a distant astronomical object
C) the milky way
D) the sum total of all matter and energy, that is, everything within and between all galaxies
e) the dark sky

D) the sum total of all matter and energy, that is, everything within and between all galaxies
Which of the following has your “address” in the correct order?
A) you, earth, solar system, local group, local supercluster, milky way
B) you, earth, solar system, milky way, local supercluster, local group
C) you, earth, solar system, local group, milky way, local supercluster
D) you, earth, local group, local supercluster, solar system, milky way
E) you, earth, solar system, milky way, local group, local supercluster
E) you, earth, solar system, milky way, local group, local supercluster
About where is our solar system located within the milky way galaxy?
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 galaxy
C) about two thirds of the way from the center of the galaxy to the outskirts of the galaxy
D) near the far outskirts of the galactic disk
E) in the halo of the galaxy above the galactic disk
C) about two thirds of the way from the center of the galaxy to the outskirts of the galaxy

Roughly how many stars are in the Milky Way Galaxy?

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

B) 100 billion

Modern telescopes are capable of seeing bright galaxies up to about

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

D) 10 billion light-years away
Suppose we imagine the Sun to be about the size of a grapefruit. How big an area would the
orbits of the eight planets of the solar system cover?A) the size of a typical dorm room
B) the size of a typical campus building
C) the size of a typical campus
D) the size of a small city
E) the size of a western state (e.g., Colorado)
C) the size of a typical campus

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

A) Average distances are increasing between star systems within galaxies.
B) Everything in the universe is gradually growing in size.
C) Average distances are increasing between galaxies.
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.

C) Average distances are increasing between galaxies

The age of the universe is

A) between 10 million and 16 million years.
B) between 100 million and 160 million years.
C) between 1 billion and 1.6 billion years.
D) between 10 billion and 16 billion years.
E) between 100 billion and 160 billion years.

D) between 10 billion and 16 billion years

How are galaxies important to our existence?

A) Without galaxies, there could not have been a Big Bang.
B) Without galaxies, the universe could not be expanding.
C) Galaxies prevent planets from leaving their orbits around stars; e.g., our galaxy prevents Earth
from leaving its orbit of the Sun.
D) Galaxies recycle heavy elements produced in stars into future generations of stars.
E) Galaxies provide the gravity that prevents us from falling off Earth.

D) Galaxies recycle heavy elements produced in stars into future generations of stars

Earth is made mostly of metals and rocks. Where did this material come from?

A) It was produced in the Big Bang.
B) It was created by chemical reactions in interstellar space.
C) It was produced by nuclear fusion in stars.
D) It was made by our Sun.
E) It was made by nuclear fission of uranium and other radioactive materials.

C) It was produced by nuclear fusion in stars

What is nuclear fusion?

A) an explosion caused by putting together two volatile chemicals
B) the process of splitting nuclei to produce energy
C) the process of turning matter into pure energy
D) the process of combining lightweight nuclei to make heavier nuclei
E) a process that only occurs in bombs

D) The process of combining lightweight nuclei to make heavier nuclei

Why did Carl Sagan say that we are star stuff?

A) The composition of most stars (mostly hydrogen and helium) is about the same as the
composition of our bodies.
B) Cosmic rays reaching Earth from distant astronomical sources may be one source of
mutations that help evolution along.
C) Nearly every atom from which we are made once (before the solar system formed) was inside
of a star.
D) Nearly every atom from which we are made was once inside our star, the Sun.
E) Sagan thought that all of us have the potential to be movie (or TV) stars like he was.

C) Nearly every atom from which we are made once (before the solar system formed) was inside a star

Which of the following statements does not use the term light-year in an appropriate way?

A) It’s about 4 light-years from here to Alpha Centauri.
B) It will take me light-years to complete this homework assignment.
C) A light-year is about 10 trillion kilometers.
D) It will take the Voyager spacecraft about 20,000 years to travel just 1 light-year.
E) The Milky Way Galaxy is about 100,000 light-years in diameter.

B) It will take me light-years to complete this homework assignment
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.)A) 300,000 km
B) 18 million km
C) 100 million km
D) 1.08 billion km
E) 9.46 trillion km
D) 1.08 billion km
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?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

What do we mean by the observable universe?

A) the part of the universe that we can see with the naked eye
B) the part of the universe that we can see through telescopes
C) the part of the universe that could be observed in principle, including things that may require
future technologies
D) the compendium of all objects that we have observed to date
E) the entire universe, since it is inconceivable that there could be parts of the universe that we
cannot observe

C) the part of the universe that could be observed in principle, including things that may require future technologies
Suppose we imagine the Sun to be about the size of a grapefruit. Which of the following
describes the size and distance of Earth on the same scale?A) Earth is the size of a point about 1 meter away from the Sun.
B) Earth is the size of a golf ball about 1 meter away from the Sun.
C) Earth is the size of a point about 15 meters away from the Sun.
D) Earth is the size of a golf ball about 15 meters away from the Sun.
E) Earth is the size of a marble about 25 miles away from the Sun.
C) Earth is the size of a point about 15 meters away from the sun

What is the Sun mainly made of?

A) hydrogen and oxygen
B) hydrogen and helium
C) carbon and nitrogen
D) oxygen and carbon
E) nearly equal portions of all the elements

B) hydrogen and helium

Which of the following is smallest?

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

Which of the following is largest?

A) size of a typical galaxy
B) size of Pluto’s orbit
C) distance to the nearest star (other than our Sun)
D) 1 light-year

A) size of a typical galaxy

On the 1-to-10-billion scale, about how far is it to the nearest stars besides the Sun?

A) 4 kilometers
B) 400 kilometers
C) 1,000 kilometers
D) 4,400 kilometers
E) 10,000 kilometers

D) 4,400 kilometers
Suppose we imagine the Sun to be about the size of a grapefruit. How far away are the
nearest stars (the three stars of Alpha Centauri)?A) the length of a football field
B) 2.5 miles
C) 250 miles
D) 2,500 miles
E) 25,000 miles
D) 2,500 miles
If we use 1 millimeter to represent 1 light-year, how large in diameter is the Milky Way
Galaxy?A) 100 millimeters
B) 100 meters
C) 1 kilometer
D) 100 kilometers
E) 1 million millimeters
B) 100 meters

Which of the following best describes the Milky Way Galaxy?

A) a spiral galaxy with a disk about 100,000 light-years in diameter and containing between 100
billion and 1 trillion stars
B) a spiral galaxy with a disk about 1 billion kilometers in diameter and containing between 100
million and 1 billion stars
C) a 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 spiral galaxy with a disk about 100,000 light-years in diameter and containing between 100 billion and 1 trillion stars
How long would it take to count all the stars in the Milky Way Galaxy at a rate of one star
per second?A) several days
B) several weeks
C) several years
D) several thousand years
E) hundreds of thousands of years
D) several thousand years

How many galaxies are there in the observable universe?

A) roughly (within a factor of 10) the same as the number of stars in our galaxy
B) roughly a thousand times more than the number of stars in our galaxy
C) about as many as the number of stars we see in the sky with our naked eyes
D) about as many as the number of grains of sand on all the beaches on Earth
E) an infinite number

A) roughly (within a factor of 10) the same as the number of stars in our galaxy
If you represented each star by a grain of sand, how much sand would it take to represent all
the stars in the universe?A) all the sand in a typical playground sandlot
B) all the sand on Miami Beach
C) all the sand on the beaches of California
D) all the sand on the beaches in the United States
E) more than all the sand on all the beaches on Earth
E) more than all the sand on all the beaches on earth

On the scale of the cosmic calendar, in which the history of the universe is compressed to 1

year, how long has human civilization (i.e., since ancient Egypt) existed?

A) about half the year
B) about a month
C) a few hours
D) a few seconds
E) less than a millionth of a second

D) a few seconds
On a cosmic calendar, in which the history of the universe is compressed into 1 year, when
did the dinosaurs become extinct?A) in late December
B) in late November
C) in late October
D) in late September
E) in late August
A) in late December
On a cosmic calendar, in which the history of the universe is compressed into 1 year, when
did Kepler and Galileo first discover that we live on a planet in a solar system?A) 1 second ago
B) 1 day ago
C) 1 week ago
D) December 25
E) December 30
A) 1 second ago
On a cosmic calendar, in which the history of the universe is compressed into one year, how
long is the average human life span?A) 0.2 millisecond
B) 0.2 second
C) 2 seconds
D) 2 minutes
E) 2 hours
B) 0.2 seconds

Approximately how fast are you moving with the rotation of Earth?

A) 13,000 km/hr
B) 1,300 km/hr
C) 130 km/hr
D) 13 km/hr
E) not moving at all

B) 1,300 km/hr

What is an astronomical unit?

A) the average speed of Earth around the Sun
B) the length of time it takes Earth to revolve around the Sun
C) the average distance from Earth to the Sun
D) the diameter of Earth’s orbit around the Sun
E) any basic unit used in astronomy

C) the average distance from Earth to the Sun

Which of the following statements about the ecliptic plane is not true?

A) It is the plane of Earth’s orbit around the Sun.
B) It is the plane of the Moon’s orbit around Earth.
C) During a solar eclipse, the Moon lies in the ecliptic plane.
D) During a lunar eclipse, the Moon lies in the ecliptic plane.
E) The nodes of the Moon’s orbit lie in the ecliptic plane.

B) it is the plane of the moon’s orbit around earth
Patterns of stars in constellations hardly change in appearance over times of even a few
thousand years. Why?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.
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

How long does it take our solar system to complete one orbit around the Milky Way Galaxy?

A) 10 thousand years
B) 230 thousand years
C) 1 million years
D) 100 million years
E) 230 million years

E) 230 million years

Which of the following statements about the Milky Way Galaxy is not true?

A) It contains between 100 billion and 1 trillion stars.
B) Our solar system is located very close to the center of the Milky Way Galaxy.
C) Our view of distant objects is obscured by gas and dust when we look into the galactic plane.
D) The galaxy is about 100,000 light-years in diameter.
E) One rotation of the galaxy takes about 200 million years.

B) our solar system is located very close to the center of the milky way galaxy

Which of the following correctly lists speeds from slowest to fastest?

A) Earth’s speed of revolution about the Sun, typical speeds of stars in the local solar
neighborhood relative to us, Earth’s speed of rotation on its axis, the speed of our solar system
orbiting the center of the Milky Way Galaxy, the speeds of very distant galaxies relative to us
B) Earth’s speed of rotation on its axis, Earth’s speed of revolution about the Sun, typical speeds
of stars in the local solar neighborhood relative to us, the speed of our solar system orbiting the
center of the Milky Way Galaxy, the speeds of very distant galaxies relative to us
C) the speeds of very distant galaxies relative to us, typical speeds of stars in the local solar
neighborhood relative to us, Earth’s speed of rotation on its axis, Earth’s speed of revolution
about the Sun, the speed of our solar system orbiting the center of the Milky Way Galaxy
D) the speed of our solar system orbiting the center of the Milky Way Galaxy, Earth’s speed of
revolution about the Sun, Earth’s speed of rotation on its axis, the speeds of very distant galaxies
relative to us, typical speeds of stars in the local solar neighborhood relative to us
E) Earth’s speed of revolution about the Sun, Earth’s speed of rotation on its axis, the speed of
our solar system orbiting the center of the Milky Way Galaxy, typical speeds of stars in the local
solar neighborhood relative to us, the speeds of very distant galaxies relative to us

B) Earth’s speed of rotation on its axis, Earth’s speed of revolution around the Sun, typical speeds of stars in the local solar neighborhood relative to us, the speed of our solar system orbiting the center of the Milky Way Galaxy, the speeds of very distant galaxies relative to us

Most of the mass in the Milky Way Galaxy is located

A) in the halo (above/below the disk).
B) within the disk.
C) in the stars in the spiral arms.
D) in the gas and dust.
E) in the central bulge of the galaxy.

A) in the halo (above/below the disk)

The distribution of the mass of the Milky Way Galaxy is determined by

A) counting the number of stars.
B) determining the amount of gas and dust.
C) studying how stars are distributed in the Milky Way.
D) studying the rotation of the galaxy.
E) weighing various parts of the Milky Way.

D) studying the rotation of the galaxy
From the fact that virtually every galaxy is moving away from us and more distant galaxies
are moving away from us at a faster rate than closer ones, we conclude thatA) the Milky Way Galaxy is expanding.
B) we are located at the center of the universe.
C) the farthest galaxies will eventually be moving faster than the speed of light.
D) the universe is expanding.
E) the universe is shrinking.
D) the universe is expanding
By studying distant galaxies in the 1920s, Hubble made which of the following important
discoveries that led us to conclude that the universe is expanding?A) All galaxies contain billions of stars, and all galaxies have spiral shapes.
B) All galaxies were born at the same time, and all will die at the same time.
C) All galaxies outside the Local Group are moving away from us, and the farther away they are,
the faster they’re going.
D) All galaxies outside the Local Group are orbiting the Local Group.
E) All galaxies outside the Local Group are moving away from us, and all are moving away at
nearly the same speed.
C) All galaxies outside the Local Group are moving away from us, and the farther away they are, the faster they’re going
Imagine that we put a raisin cake into the oven, with each raisin separated from the others by
1 cm. An hour later, we take it out and the distances between raisins are 3 cm. If you lived in one
of the raisins and watched the other raisins as the cake expanded, which of the following would
you conclude?A) All raisins would be moving away from you at the same speed.
B) More distant raisins would be moving away from you faster.
C) More distant raisins would be moving away from you more slowly.
D) It depends: If you lived in a raisin near the edge of the cake, you’d see other raisins moving
away from you, but they’d be coming toward you if you lived in a raisin near the center of the
cake.
B) More distant raisins would be moving away from you faster
Which scientists played a major role in overturning the ancient idea of an Earth-centered
universe, and about when?A) Copernicus, Kepler, and Galileo; about 400 years ago
B) Aristotle and Copernicus; about 400 years ago
C) Newton and Einstein; about 100 years ago
D) Huygens and Newton; about 300 years ago
E) Aristotle and Plato; about 2,000 years ago
A) Copernicus, Kepler and Galileo; about 400 years ago

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