Exam
Name___________________________________
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
1)
Which of the following is largest?
1)
A)
size of a typical galaxy
B)
1 light–year
C)
distance to the nearest star (other than our Sun)
D)
size of Pluto’s orbit
2)
On a scale where the Sun is about the size of a grapefruit and the Earth is about 15 meters away,
how far away are the nearest stars besides the Sun?
2)
A)
100 meters
B)
about the distance across the state of Delaware
C)
about the distance across the United States
D)
about the distance across 50 football fields
3)
Stars nearby to our sun have an average relative speed of about 70,000 km/hour. How fast is that in
km/s?
3)
A)
about 4.2 million km/s
B)
about 1200 km/s
C)
about 20 km/s
D)
about 3000 km/s
4)
On a scale in which the distance from Earth to the Sun is about 15 meters, the distance from Earth
to the Moon is ________.
4)
A)
small enough to fit within your hand
B)
about 5 meters
C)
about 1 meter
D)
about 30 meters
5)
The number of stars in the Milky Way Galaxy is approximately ________.
5)
A)
a few hundred billion
B)
a few hundred
C)
a few hundred million
D)
a few hundred thousand
6)
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)
6)
A)
about 4 days
B)
about 4 minutes
C)
about 4 seconds
D)
about 4 hours
7)
One light–hour is the distance light travels in one hour. The speed of light is about 300,000 km/s
(3 × 105 km/s). How far is 1 light–hour?
7)
A)
18 million km (18,000,000, or 1.8 × 107 km)
B)
9.46 trillion km (9,460,000,000,000, or 9.46 × 1012 km)
C)
1.08 billion km (1,080,000,000, or 1.08 ×109 km)
D)
300 thousand km (300,000, or 3 × 105 km)
8)
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 one light–minute?
8)
A)
1.08 billion km (1,080,000,000, or 1.08 × 109 km)
B)
300 thousand km (300,000, or 3 × 105 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)
9)
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?
9)
A)
about a month
B)
a few hours
C)
about half the year
D)
a few seconds
E)
less than a millionth of a second
10)
Relative to the age of the universe, how old is our solar system?
10)
A)
It is about 1% as old as the universe.
B)
It is between about 5% and 10% as old as the universe.
C)
It is nearly the same age as the universe.
D)
It is about one–third the age of the universe.
11)
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?
11)
A)
47.3 trillion km (47,300,000,000,000, or 4.73 × 1013 km)
B)
1.5 million km (1,500,000, or 1.5 × 106 km)
C)
5.4 billion km (5,400,000,000, or 5.4 × 109 km)
D)
90 million km (90,000,000, or 9 × 107 km)
12)
Which of the following correctly lists speeds from slowest to fastest?
12)
A)
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
B)
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
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 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 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
13)
Astronomers infer that the universe is expanding because distant galaxies all appear to ________.
13)
A)
be moving away from us, with more distant ones moving faster
B)
rotate rapidly
C)
be growing in size
D)
be made mostly of dark matter
14)
The total number of stars in the observable universe is about ________.
14)
A)
the same as the number of atoms that make up the Earth
B)
the same as the number of grains of sand in a school sandbox
C)
the same as the number of grains of sand on all the beaches on Earth
D)
100 billion
15)
How do scientists estimate how old the universe is?
15)
A)
They measure the speeds and distances of galaxies, and calculate the time it took for them to
travel that distance.
B)
They look up the answer in a book.
C)
They make a guess; no one really knows how old the universe is.
D)
They measure the abundances of radioactive elements in meteorites, and use their half–lives
to calculate the age.
E)
They measure how fast the Sun is losing energy, and how much energy it has to lose.
16)
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?
16)
A)
Earth is the size of a golf ball about 15 meters 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 point about 1 meter away from the Sun.
E)
Earth is the size of a marble about 25 miles away from the Sun.
17)
The distribution of the mass of the Milky Way Galaxy is determined by
17)
A)
determining the amount of gas and dust.
B)
weighing various parts of the Milky Way.
C)
studying the rotation of the galaxy.
D)
counting the number of stars.
E)
studying how stars are distributed in the Milky Way.
18)
Which statement correctly locates the formation of the Earth and the appearance of the first humans
on the cosmic calendar, which compresses the 14–billion year history of the universe into one
“year,” where “now” is exactly midnight, Dec 31?
18)
A)
Earth forms in early September, life begins in November, and humans appear on Dec 15.
B)
Earth forms in January, life begins in April, and humans appear in early December.
C)
Earth forms in January, life begins in September, and humans appear in October.
D)
Earth forms in early September, life begins in late September, humans appear a few hours
before midnight, Dec 31.
19)
A television advertisement claiming that a product is light–years ahead of its time does not make
sense because ________.
19)
A)
light–years can only be used to talk about light
B)
a light–year is an astronomically large unit, so a product could not possibly be so advanced
C)
it doesn’t specify the number of light–years
D)
it uses “light–years” to talk about time, but a light–year is a unit of distance
20)
According to current scientific estimates, when did the Big Bang occur?
20)
A)
about 20 billion years ago
B)
about 14 billion years ago
C)
about 65 million years ago
D)
about 10 billion years ago
E)
about 4.5 billion years ago
21)
Our solar system is located about 27,000 light–years from the galactic center. How far does our
solar system travel in one orbit?
21)
A)
100,000 light–years
B)
170,000 light–years
C)
54,000 light–years
D)
85,000 light–years
Explanation:
22)
On the 1–to–10–billion scale, about how far is it to the nearest stars besides the Sun?
22)
A)
10,000 kilometers
B)
4 kilometers
C)
1,000 kilometers
D)
4,400 kilometers
E)
400 kilometers
23)
Which of the following statements about the Milky Way Galaxy is not true?
23)
A)
Our solar system is located very close to the center of the Milky Way Galaxy.
B)
It contains between 100 billion and 1 trillion stars.
C)
The galaxy is about 100,000 light–years in diameter.
D)
One rotation of the galaxy takes about 200 million years.
24)
How long does it take our solar system to complete one orbit around the Milky Way Galaxy?
24)
A)
230 thousand years
B)
1 million years
C)
10 thousand years
D)
230 million years
E)
100 million years
25)
If we imagine the history of the universe compressed into one year, dinosaurs became extinct
________.
25)
A)
yesterday morning
B)
about 6 months ago
C)
about 3 weeks ago
D)
about an hour ago
26)
Which of the following best describes the Milky Way Galaxy?
26)
A)
a spherically shaped collection of about 1 million stars that is about 100 light–years in
diameter
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 spiral galaxy with a disk about 100,000 light–years in diameter and containing about 100,000
stars
27)
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?
27)
A)
1 week ago
B)
December 25
C)
December 30
D)
1 second ago
E)
1 day ago
28)
Why do the patterns of the stars in our sky look the same from year to year?
28)
A)
because the stars in the constellations are not moving
B)
because the stars in the constellations move so slowly–typically about the speed of a
snail–that their motions are not noticeable
C)
because the stars in the constellations are so far away
D)
because the stars in the constellations all move at the same speeds and in the same directions,
so they don’t change their relative positions
29)
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?
29)
A)
several years
B)
several days
C)
several weeks
D)
several thousand years
30)
One light–year is the distance light travels in one year. The speed of light is about 300,000 km/s
(3 × 105 km/s). How far is 1 light–year?
30)
A)
300 thousand km (300,000, or 3 × 105 km)
B)
18 million km (18,000,000, or 1.8 × 107 km)
C)
9.46 trillion km (9,460,000,000,000, or 9.46 × 1012 km)
D)
1.08 billion km (1,080,000,000, or 1.08 × 109 km)
31)
When we look at an object that is 1,000 light–years away, we see it ________.
31)
A)
as it was 1,000 light–years ago
B)
looking just the same as our ancestors would have seen it 1,000 years ago
C)
as it is right now, but it appears 1,000 times dimmer
D)
as it was 1,000 years ago
32)
What is the Sun mainly made of?
32)
A)
carbon and nitrogen
B)
nearly equal portions of all the elements
C)
hydrogen and helium
D)
oxygen and carbon
E)
hydrogen and oxygen
33)
Our solar system is located about 27,000 light–years from the galactic center. How far does our
solar system travel in one orbit?
33)
A)
1018 km
B)
8.5 × 1017 km
C)
5.4 × 1017 km
D)
1.7 × 1018 km
34)
Using the ideas discussed in your textbook, in what sense are we “star stuff”?
34)
A)
We could not survive without light from our star, the Sun.
B)
The overall chemical composition of our bodies is about the same as that of stars.
C)
Nearly every atom from which we are made was once inside of a star.
D)
Movie stars and other people are all made of the same stuff, so we all have the potential to be
famous.
35)
What is the ecliptic plane?
35)
A)
the plane of Earth’s orbit around the Sun
B)
the plane of the Sun’s equator
C)
the plane of the Milky Way Galaxy
D)
the plane of Earth’s equator
36)
Suppose we make a scale model of our solar system, with the Sun the size of a grapefruit. Which of
the following best describes what the planets would look like?
36)
A)
The planets are all much smaller than the Sun. Four planets are located within a few
centimeters of the Sun, and four planets are located at distances ranging up to about a meter.
B)
The planets are all much smaller than the Sun. Four planets are within about 20 meters of the
Sun, while the rest planets are spread much farther apart.
C)
The planets range in size from about the size of a marble to the size of a baseball. They are
spread out over a region about the size of a football field.
D)
The planets are all much smaller than the Sun and are spread out evenly over a distance
about the length of a large classroom.
37)
Which of the following best describes what we mean by the universe?
37)
A)
the sum total of all matter and energy
B)
The universe is another name for our Milky Way Galaxy.
C)
a vast collection of stars that number as many as the grains of sand on all the beaches on Earth
D)
all the galaxies in all the superclusters
38)
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?
38)
A)
the size of a typical dorm room
B)
the size of a typical campus
C)
the size of a small city
D)
the size of a western state (e.g., Colorado)
E)
the size of a typical campus building
39)
Jupiter is about 5 AU from the Sun. In a ten billion to one scale model, Jupiter is
39)
A)
about 15 meters from the Sun.
B)
about 75 meters from the Sun.
C)
about a kilometer from the Sun.
D)
less than one meter from the Sun.
40)
The term observable universe refers to ________.
40)
A)
the portion of the universe that can be seen by the naked eye
B)
that portion of the universe that we have so far photographed through telescopes
C)
that portion of the universe that we can see in principle, given the current age of the universe
D)
the portion of the universe that is not hidden from view by, for example, being below the
horizon
41)
Suppose we look at two distant galaxies: Galaxy 1 is twice as far away as Galaxy 2. In that case,
________.
41)
A)
we are seeing Galaxy 1 as it looked at a later time in the history of the universe than Galaxy 2
B)
Galaxy 2 must be twice as old as Galaxy 1
C)
we are seeing Galaxy 1 as it looked at an earlier time in the history of the universe than Galaxy
2
D)
Galaxy 1 must be twice as big as Galaxy 2
42)
Light takes approximately one second to travel from the Earth to the Moon. This means that the
Moon is approximately
42)
A)
1 astronomical unit from the Earth.
B)
3,000 kilometers from the Earth.
C)
300,000 kilometers from the Earth.
D)
twice the distance from the Earth to the Sun.
E)
1 light year from the Earth.
43)
How long does it take the Earth to complete one orbit around the Sun?
43)
A)
one day
B)
one month
C)
one week
D)
one year
E)
The time it takes Earth to orbit the Sun changes significantly from one orbit to the next.
44)
Rank the following 3 items from nearest to farthest. Hint: the Orion Nebula is a cloud of gas in
which young stars are being born within the Milky Way, about 1,500 light–years away.
44)
A)
star in the center of the Milky Way, Orion Nebula, Alpha Centauri
B)
Alpha Centauri, Orion Nebula, star in the center of the Milky Way
C)
star in the center of the Milky Way, Alpha Centauri, Orion Nebula
45)
One of the main reasons the Hubble Space Telescope was built and launched was to measure how
fast the universe is expanding. If the expansion turns out to be faster than we thought, our estimate
for the age of the universe will be
45)
A)
unaffected.
B)
older (more time between now and the Big Bang).
C)
younger (less time between now and the Big Bang).
46)
Earth is made mostly of metals and rocks. Where did this material come from?
46)
A)
It was created by chemical reactions in interstellar space.
B)
It was produced in the Big Bang.
C)
It was made by nuclear fission of uranium and other radioactive materials.
D)
It was made by our Sun.
E)
It was produced by nuclear fusion in stars.
47)
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.)
47)
A)
100 million km
B)
300,000 km
C)
1.08 billion km
D)
9.46 trillion km
E)
18 million km
48)
An astronomical unit (AU) is ________.
48)
A)
the average distance between any planet and the Sun
B)
any very large unit, such as a light–year
C)
the average distance between Earth and the Sun
D)
the current distance between Earth and the Sun
49)
Most of the mass in the Milky Way Galaxy is located
49)
A)
in the halo (above/below the disk).
B)
within the disk.
C)
in the gas and dust.
D)
in the central bulge of the galaxy.
E)
in the stars in the spiral arms.
50)
Our textbook discusses the cosmic calendar, a model of the history of the universe scaled to a single
year. The length of time represented by one month on this cosmic calendar is therefore
50)
A)
about 1000 years.
B)
about ten billion years.
C)
about ten million years.
D)
about one billion years.
E)
about one million years.
51)
On a cosmic calendar, in which the history of the universe is compressed into 1 year, when did the
dinosaurs become extinct?
51)
A)
in late September
B)
in late August
C)
in late November
D)
in late October
E)
in late December
52)
A typical galaxy is a ________.
52)
A)
system consisting of one or a few stars orbited by planets, moons, and smaller objects
B)
nearby object orbiting a planet
C)
collection of a few hundred million to a trillion or more stars, bound together by gravity
D)
relatively small, icy object orbiting a star
E)
large, glowing ball of gas powered by nuclear energy
53)
Which of the following statements does not use the term light–year in an appropriate way?
53)
A)
The Milky Way Galaxy is about 100,000 light–years in diameter.
B)
A light–year is about 10 trillion kilometers.
C)
It will take the Voyager spacecraft about 20,000 years to travel just 1 light–year.
D)
It’s about 4 light–years from here to Alpha Centauri.
E)
It will take me light–years to complete this homework assignment.
54)
Which object has aged the most since it emitted the light we see today?
54)
A)
a star in the Andromeda Galaxy
B)
a star near the center of the Milky Way
C)
Pluto
D)
the Sun
55)
If the entire galaxy (with a diameter of 100,000 light years) were represented by a circle with a
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)?
55)
A)
about 200 meters (about 2 football fields)
B)
about 20 meters (about the size of a large classroom)
C)
about 2 meters (about 2 long footsteps)
D)
about 0.2 meters (about the length of an adult’s forearm)
56)
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?
56)
A)
the galaxy that appears largest to us
B)
the galaxy that appears bluest to us
C)
the galaxy that is furthest from us
D)
the galaxy that is closest to us
E)
All galaxies would appear to have the same age.
57)
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
57)
A)
the universe is shrinking.
B)
the universe 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 Milky Way Galaxy is expanding.
58)
Approximately how fast is a person located at the Earth’s equator traveling due to the rotation of
the Earth?
58)
A)
17,000 km/hr
B)
1,700 km/hr
C)
17 km/hr
D)
170 km/hr
E)
not moving at all
59)
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?
59)
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.
60)
Place the following items in order of actual physical size, from smallest to largest.
60)
A)
star, planet, solar system, galaxy
B)
planets and stars are about the same size, solar system, galaxy
C)
planet, star, galaxy, solar system
D)
planet, star, solar system, galaxy
E)
star, planet, galaxy, solar system
61)
Which of the following is smallest?
61)
A)
1 light–second
B)
size of a typical star
C)
1 AU
D)
size of a typical planet
62)
Light travels at 300,000 km/sec. About how far does light travel in 10 years?
62)
A)
about 10 light–years
B)
about 30,000 kilometers
C)
about 3,000,000 kilometers
D)
about 10 trillion kilometers
E)
about 30 million seconds
63)
What do we mean when we say that the universe is expanding?
63)
A)
The statement is not meant to be literal; rather, it means that our knowledge of the universe is
growing.
B)
Within galaxies, average distances between star systems are increasing with time.
C)
Everything in the universe is gradually growing in size.
D)
Average distances between galaxies are increasing with time.
64)
Based on observations of the universal expansion, the age of the universe is about ________.
64)
A)
14 trillion years
B)
14 million years
C)
14 billion years
D)
14,000 years
65)
By studying distant galaxies in the 1920s, Hubble made the following important discovery that led
us to conclude that the universe is expanding.
65)
A)
All galaxies outside the Local Group are moving away from us, and all are moving away at
nearly the same speed.
B)
All galaxies outside the Local Group are orbiting the Local Group.
C)
All galaxies were born at the same time, and all will die at the same time.
D)
All galaxies contain billions of stars, and all galaxies have spiral shapes.
E)
All galaxies outside the Local Group are moving away from us, and the farther away they are,
the faster they’re going.
66)
How are galaxies important to our existence?
66)
A)
Without galaxies, the universe could not be expanding.
B)
Deep in their centers, galaxies created the elements from which we are made.
C)
Galaxies recycle material from one generation of stars to the next, and without this recycling
we could not exist.
D)
Without galaxies, there could not have been a Big Bang.
67)
How do the speeds at which we are moving with Earth’s rotation and orbit compare to the speeds
of more familiar objects?
67)
A)
Earth’s rotation carries most people around the axis at about the speed of a car on the
freeway, and Earth’s orbit carries us around the Sun at about the speed of a commercial jet.
B)
Earth‘s rotation carries most people around the axis faster than a commercial jet travels, and
Earth’s orbit carries us around the Sun faster than the Space Shuttle orbits Earth.
C)
Earth’s rotation carries most people around the axis at about the speed of a commercial jet,
and Earth’s orbit carries us around the Sun at about the speed of a military jet.
D)
Earth‘s rotation carries most people around the axis at about the speed at which the Space
Shuttle orbits Earth, and Earth’s orbit carries us around the Sun at nearly the speed of light.
68)
You have taken a picture of a galaxy 1 billion light years away. That picture shows
68)
A)
a galaxy that is 13 billion years old.
B)
a galaxy that is 1 billion light years old.
C)
a galaxy that is 1 billion years old.
D)
a galaxy as it was 1 billion years ago.
69)
Our solar system consists of ________.
69)
A)
the Sun and several nearby stars, as well as the planets and other objects that orbit these stars
B)
a few hundred billion stars, bound together by gravity
C)
the Sun and the planets, and nothing else
D)
the Sun and all the objects that orbit it
70)
Where is our solar system located within the Milky Way Galaxy?
70)
A)
roughly halfway between the center and the edge of the visible disk of the galaxy
B)
in the halo of the galaxy
C)
very near the center of the galaxy
D)
at the far edge of the galaxy’s visible disk
71)
How many galaxies are there in the observable universe?
71)
A)
roughly a thousand times more than the number of stars in our galaxy
B)
about as many as the number of stars we see in the sky with our naked eyes
C)
infinity
D)
roughly (within a factor of 10) the same as the number of stars in our galaxy
E)
about as many as the number of grains of sand on all the beaches on Earth
72)
Which of the following is not a general difference between a planet and a star?
72)
A)
Planets are dimmer than stars.
B)
All planets are made of rock, and all stars are made of gas.
C)
Planets orbit stars, while stars orbit the center of the galaxy.
D)
Planets are smaller than stars.
73)
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)
73)
A)
1/50 of a second (0.02s)
B)
1/ 6000 of a second (0.00015 s)
C)
1/2 of a second (0.5 s)
D)
1/300,000 of a second (0.0000033 s)
74)
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)?
74)
A)
the length of a football field
B)
250 miles
C)
2.5 miles
D)
25,000 miles
E)
2,500 miles
75)
Wendy measures a recession velocity for two distant galaxies, well outside our Local Group of
galaxies. Galaxy A has a recession velocity of 35,000 km/s and Galaxy B has a recession velocity of
70,000 km/s. What can she say about the distances to those galaxies?
75)
A)
She can’t say anything about the distances to Galaxy A or B.
B)
Galaxy B is twice as far as Galaxy A.
C)
Galaxy A is four times as far as Galaxy B.
D)
Galaxy B is four times as far as Galaxy A.
E)
Galaxy A is twice as far as Galaxy B.
76)
The farthest bright galaxies that modern telescopes are capable of seeing are up to
76)
A)
10 billion light years away.
B)
1 trillion light years away.
C)
1 million light years away.
D)
1 billion light years away.
E)
10 million light years away.
A
77)
The speed of light is about 300,000 km/s (3 × 105 km/s). How far does light travel in 30 seconds?
77)
A)
10 thousand km (10,000, or 106 km)
B)
9 million km (9,000,000, or 9 × 106 km)
C)
300 thousand km (300,000, or 3 × 105 km)
D)
900 thousand km (900,000, or 9 × 105 km)
B
78)
What is nuclear fusion?
78)
A)
a process that only occurs in bombs
B)
the process of splitting nuclei to produce energy
C)
an explosion caused by putting together two volatile chemicals
D)
the process of turning matter into pure energy
E)
the process of combining lightweight nuclei to make heavier nuclei
E
B
79)
How many seconds are in one year? (Calculate this, do not look it up.)
79)
A)
about 30 million (30,000,000, or 3 × 107)
B)
about 380 million (380,000,000, or 3.8 × 108)
C)
about 3,600 (3.6 × 103)
D)
about 86 thousand (86,000, or 8.6 × 105)
80)
If we use 1 millimeter to represent 1 light–year, how large in diameter is the Milky Way Galaxy?
80)
A)
1 million millimeters
B)
100 kilometers
C)
1 kilometer
D)
100 millimeters
E)
100 meters
E
81)
In a ten–billion to one scale model, the Sun and the Earth are about the size of
81)
A)
a basketball and a grape.
B)
a grapefruit and a grain of sand.
C)
a grape and a grain of sand.
D)
a grapefruit and a grape.
B
82)
Which of the following has your “cosmic address” in the correct order?
82)
A)
you, Earth, solar system, Milky Way Galaxy, Local Group, Local Supercluster, universe
B)
you, Earth, Local Group, Local Supercluster, solar system, Milky Way Galaxy, universe
C)
you, Earth, Milky Way Galaxy, solar system, Local Group, Local Supercluster, universe
D)
you, Earth, solar system, Local Group, Local Supercluster, Milky Way Galaxy, universe
E)
you, Earth, solar system, Local Group, Milky Way Galaxy, Local Supercluster, universe
A
A
83)
Which of the following correctly describes the concept of galactic recycling?
83)
A)
Life is continuously being spread from star to star in the Milky Way.
B)
Stars near the center of the Milky Way are continually recycled to the outskirts of the disk by
their orbital motion.
C)
New stars are continuously being formed in the Milky Way out of gas that has been ejected
from a previous generation of stars.
D)
In the formation of a star, no matter is wasted as all excess material ends up recycled into
planets.
E)
New galaxies are continuously being formed out of gas ejected from a previous generation of
galaxies.
84)
One of the most fundamental discoveries about the universe has been that it is expanding. “The
universe is expanding” means
84)
A)
galaxies are growing with time.
B)
our estimate for the size of the universe has increased over the last century.
C)
distances between most galaxies are getting larger.
D)
the cosmological horizon is growing with time.
85)
What do astronomers mean by the Big Bang?
85)
A)
the event that marked the beginning of the expansion of the universe
B)
the explosion of a massive star at the end of its life
C)
a gigantic explosion that blew all the galaxies in the universe to smithereens
D)
the event that marked the birth of our solar system
86)
What is the diameter of the galaxy, in km?
86)
A)
about 1 billion trillion km (1021 km)
B)
about 10 trillion km (1013 km)
C)
about 1 million trillion km (1018 km)
D)
about 100,000 km (105 km)
87)
Rank the following 4 items by how long it takes for light to reach us from these objects, from
shortest to longest.
87)
A)
Pluto, Sun, the Andromeda Galaxy, center of the Milky Way
B)
Sun, Pluto, the Andromeda Galaxy, center of the Milky Way
C)
Sun, Pluto, center of the Milky Way, the Andromeda Galaxy
D)
the Andromeda Galaxy, the center of the Milky Way, Pluto, Sun
E)
Pluto, Sun, center of Milky Way, the Andromeda Galaxy
88)
Which statement about motion in the universe is not true?
88)
A)
Except for a few nearby galaxies, all other galaxies are moving away from us.
B)
The mysterious dark matter is the fastest–moving material in the universe.
C)
Your speed of rotation around Earth’s axis is faster if you live near the equator than if you live
near the North Pole.
D)
Some stars in the Milky Way Galaxy are moving toward us and others are moving away from
us.
SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.
89)
Explain why it is so difficult to see planets around other stars.
89)
90)
Briefly explain what we mean by the statement “The farther away we look in distance, the
further back we look in time.”
90)
91)
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.
91)
92)
The speed of light is 300,000 km/s. How far is a light–year? Be sure to show all work clearly
on your calculation.
92)
93)
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.”
93)
94)
Consider the following statement, and explain whether or not it is sensible: It will take me
light–years to complete this homework assignment.
94)
95)
Consider the following statement, and explain whether or not it is sensible: NASA hopes to
build a new telescope that will allow us to see 100 million light–years into the past.
95)
96)
Imagine that you could drive your car in space. Assume that you can drive at a constant
speed of 100 kilometers per hour. Suppose you started driving from the Sun. How long
would it take, in years, to reach Earth?
96)
25
97)
Starting from the Big Bang, briefly explain how our solar system came to contain the
chemical elements necessary to make Earth and living organisms.
97)
98)
Briefly explain why an expanding universe implies a beginning (called a Big Bang).
98)
99)
Consider the following statement, and explain whether or not it is sensible: NASA hopes to
build a new telescope that will allow us to see some galaxies as they appeared 8 billion
years ago.
99)
100)
Consider the following statement, and explain whether or not it is sensible: Earth is always
precisely 1 AU from the Sun.
100)
101)
Consider the following statement, and explain whether or not it is sensible: The universe is
between 10 and 16 billion light–years old.
101)
102)
Briefly explain how the Sun generates energy.
102)
TRUE/FALSE. Write ‘T’ if the statement is true and ‘F’ if the statement is false.
103)
In the grapefruit model of the solar system, it would take a few minutes to walk from the Sun to
Pluto.
103)
104)
The observable universe is the same size today as it was a few billion years ago.
104)
105)
Compared to its size, the Sun is very far away from all other stars.
105)
106)
Compared to its size, the Milky Way is very far away from all other galaxies.
106)
107)
Earth is always precisely 1 AU from the Sun.
107)
108)
Voyager 2 should reach the nearest stars (besides the Sun) in about 500 years.
108)
109)
One light year is about 10 trillion kilometers.
109)
110)
No galaxies existed before the Big Bang.
110)
111)
The solar system is a member of a galaxy containing approximately 100 billion stars.
111)
112)
The Milky Way is moving further away from most other galaxies in the universe.
112)
113)
A typical supercluster contains no more than about 10,000 stars.
113)
114)
Our solar system is located in the center of the Milky Way Galaxy.
114)
115)
The solar system contains about 100 billion stars.
115)
ESSAY. Write your answer in the space provided or on a separate sheet of paper.
116)
A Life Calendar: Make a “life calendar” for hypothetical person. Assume that this person lived 80 years and
represent the 80 year period as a single calendar year in which he or she was born on January 1st and died on
December 31st. Estimate the calendar dates on which this person reached various life milestones. For example,
when did he or she take their first step? Speak their first word? Start elementary school? Finish high school?
When did he or she retire? Does your life calendar for this particular person give any insight into human lives in
general?
117)
Stellar and galactic crowding: The comparison of objects’ sizes to the distance between them gives a sense of their
relative density, i.e., how “crowded” they are. A typical human is about 1 meter across the shoulders. Compare
the relative density of people in the case where they are standing on average 1 meter apart compared to a
situation where they are on average 10 meters apart (hint: describe the separation in units of person–size). Now,
compare the “crowding” of stars to that of galaxies. A typical star has a diameter of about 1 million km, while
the average space between stars is about 5 light–years. A typical spiral galaxy in a cluster (such as the Milky
Way) is 100,000 light–years across, and has another spiral galaxy within about 10 million light years.
118)
Light Travel Time: Because of the finite speed of light, we see more distant objects as they were in the past. For
example, we see the star Alpha Centauri as it was 4.4 years ago, and the Andromeda Galaxy as it was 2.5
million years ago. Astronomers are often asked how we know that these objects still exist when we look at them
in the night sky. How would you try to answer this question?
119)
The Observable Universe: How does the age of the universe (estimated at 14 billion years) introduce the concept
of the “observable universe?” Suppose you feel, as do many astronomers, that the universe is much larger than
the observable universe. Do you think there is any way to obtain direct evidence for this larger universe?
Answer Key
Testname: C1
Answer Key
Testname: C1
30
Answer Key
Testname: C1
31
Answer Key
Testname: C1