Download S1_Testbank

The Cosmic Perspective, 7e (Bennett et al.)
Supplement 1: Celestial Timekeeping and Navigation
S1.1 Multiple-Choice Questions
1) The amount of time between successive passes of any given star across the meridian is
A) 23 hours 56 minutes.
B) 24 hours.
C) 365.25 days.
D) 12 years.
E) 26,000 years.
Answer: A
2) Which of the following statements about sidereal and solar days is not true?
A) A solar day is 4 minutes longer than a sidereal day.
B) A solar day represents more than 360° of rotation for Earth.
C) The time it takes for a star to make one circuit of our sky is one sidereal day.
D) The time it takes for the Sun to make one circuit of our sky is one solar day.
E) The time it takes for the Moon to make one circuit of our sky is one solar day.
Answer: E
3) Which of the following is the reason for the solar day being longer than a sidereal day?
A) precession of Earth's axis
B) the tilt of Earth's axis
C) the combined effect of the rotation of Earth and its orbit about the Sun
D) Earth year being a non-integer number of Earth days
E) the non-circular orbit of Earth around the Sun
Answer: C
4) The average length of a solar day is
A) 23 hours 56 minutes.
B) 24 hours.
C) 365.25 days.
D) 12 years.
E) 26,000 years.
Answer: B
5) The lunar month is longer than the sidereal month because
A) the Moon completes the cycle of lunar phases before it completes a full orbit around Earth.
B) the Moon has to complete more than one full orbit around Earth to complete the cycle of lunar
phases.
C) the Moon orbits Earth faster than Earth orbits the Sun.
D) the Moon orbits Earth faster than Earth rotates.
E) the lunar month is based on the Moon's orbit, while the sidereal month is based on Earth's
orbit.
Answer: B
1
Copyright © 2014 Pearson Education, Inc.
6) What kind of time can be read directly from a sundial?
A) apparent solar time
B) mean solar time
C) standard time
D) daylight saving time
E) sidereal time
Answer: A
7) All the following statements are true. Which one explains why mean solar time differs from
apparent solar time?
A) The length of a solar day is not always exactly 24 hours.
B) Earth's rotation period is actually about 23 hours 56 minutes, not 24 hours.
C) Earth's axis precesses with a period of 26,000 years.
D) The Sun reaches the meridian at different times at different longitudes within the same time
zone.
E) The path of the Sun through the sky depends on both latitude and date.
Answer: A
8) Which of the following is the reason for the leap years?
A) precession of Earth's axis
B) the tilt of Earth's axis
C) the combined effect of the rotation of Earth and its orbit about the Sun
D) Earth year being a non-integer number of Earth days
E) the non-circular orbit of Earth around the Sun
Answer: D
9) Our calendar has leap years because
A) there is one more sidereal day in a year than solar days.
B) a tropical year is slightly more than 365 days.
C) there is a difference between a sidereal year and a tropical year.
D) the perihelion of Earth's orbit is slowly advancing.
Answer: B
10) Based on our current Gregorian calendar, which of the following years is not a leap year?
A) 2000
B) 2004
C) 2008
D) 2012
E) All of the above are leap years.
Answer: E
2
Copyright © 2014 Pearson Education, Inc.
11) The Sun is rising in the east and will be on your meridian in 2 hours. What time is it?
A) 2 A.M.
B) 2 P.M.
C) 10 A.M.
D) 10 P.M.
E) noon
Answer: C
12) What is the hour angle of a star crossing your meridian?
A) -6 hours
B) 0 hours
C) 6 hours
D) It depends on your latitude.
E) It depends on the right ascension of the star.
Answer: B
13) Suppose you lived at Earth's equator. Which of the following statements would not be true?
A) The north celestial pole is directly on your horizon, due north (with Polaris quite nearby).
B) The south celestial pole is directly on your horizon, due south.
C) Every day of the year, the Sun is above your horizon for 12 hours and below it for 12 hours.
D) The celestial equator goes through your sky from due east on your horizon, through 50°
altitude in the south, to due west on the horizon.
E) No stars are circumpolar.
Answer: D
14) The south celestial pole appears on your meridian at an altitude of 30° in the south. Where
are you?
A) latitude = 30°S
B) latitude = 60°S
C) latitude = 30°N
D) latitude = 60°N
E) the South Pole
Answer: A
15) Suppose you live at latitude 40°N. Which of the following describes the path of the celestial
equator through your sky?
A) It goes from due south on your horizon, to your zenith, to due north on your horizon.
B) It goes from due east on your horizon, to your zenith, to due west on your horizon.
C) It goes from due east on your horizon, to an altitude of 50° in the south, to due west on your
horizon.
D) It goes from due east on your horizon, to an altitude of 40° in the south, to due west on your
horizon.
E) It goes from due east on your horizon, to an altitude of 40° in the north, to due west on your
horizon.
Answer: C
3
Copyright © 2014 Pearson Education, Inc.
16) The time between rising and setting of a star
A) is always 12 hours.
B) depends on the star's declination.
C) depends on the star's right ascension.
D) depends on the observer's latitude.
E) depends on the observer's longitude.
Answer: D
17) Suppose you live at latitude 40°N. Which of the following describes the conditions that make
a star circumpolar?
A) Stars are circumpolar if they have declination > +50°.
B) Stars are circumpolar if they have declination > +40°.
C) Stars are circumpolar if they have right ascension > 6 hr.
D) Stars are circumpolar if they have right ascension < 6 hr.
E) No stars are circumpolar at this latitude.
Answer: A
18) Which of the following best describes the Tropic of Cancer?
A) It is any place where it is always very warm.
B) It is another name for the equator.
C) It is a place where the Sun appears to remain stationary in the sky.
D) It is a place where the Sun is directly overhead at noon on the summer solstice.
E) It is a place where the Sun is directly overhead at noon on the spring equinox.
Answer: E
19) Suppose the date is March 21 and the Sun passes through your zenith at noon. Where are
you?
A) the equator
B) the Tropic of Cancer
C) the Tropic of Capricorn
D) the Arctic Circle
E) the Antarctic Circle
Answer: A
20) Suppose the date is March 21 and the Sun crosses your meridian at an altitude of 23.5° in the
north. Where are you?
A) the equator
B) the Tropic of Cancer
C) the Tropic of Capricorn
D) the Arctic Circle
E) the Antarctic Circle
Answer: E
4
Copyright © 2014 Pearson Education, Inc.
21) Suppose the date is June 21 and the Sun never sets, just touching your northern horizon at
midnight. Where are you?
A) the equator
B) the Tropic of Cancer
C) the Tropic of Capricorn
D) the Arctic Circle
E) the Antarctic Circle
Answer: D
22) Which of the following explains why navigators a few hundred years ago found it much
more difficult to determine their longitude than their latitude?
A) Determining longitude requires mathematical techniques that were not known at the time.
B) Determining longitude without modern instruments requires being able to see the Moon.
C) Determining longitude requires much more precise measurements of angles in the sky than
does latitude.
D) Determining longitude requires having an accurate clock.
Answer: D
23) The Sun is on your meridian, and you have a UT clock that tells you it is 3 P.M. in
Greenwich. What is your longitude?
A) 3° west of Greenwich
B) 3° east of Greenwich
C) 45° west of Greenwich
D) 45° east of Greenwich
E) 30° west of Greenwich
Answer: C
24) The Sun is on your meridian, and you have a UT clock that tells you it is midnight in
Greenwich. What is your longitude?
A) 12° west of Greenwich
B) 12° east of Greenwich
C) 60° west of Greenwich
D) 60° east of Greenwich
E) 180° of longitude from Greenwich
Answer: E
25) The constellation shaped like a big square (the "great square of . . . ") is
A) Cassiopeia.
B) Pegasus.
C) Canis Major.
D) Taurus.
E) Andromeda.
Answer: B
5
Copyright © 2014 Pearson Education, Inc.
26) The constellation shaped like a W is
A) Cassiopeia.
B) Pegasus.
C) Canis Major.
D) Taurus.
E) Andromeda.
Answer: A
27) Which of the following statements about Betelgeuse is not true?
A) It is distinctly red in color.
B) We now know that it is a very massive star near the end of its life.
C) Its Arabic name means "the demon star."
D) It is one star of the three stars of the Winter Triangle, along with Procyon and Sirius.
E) It is the upper left shoulder star of the constellation Orion.
Answer: C
28) The three bright stars that make up the Winter Triangle are
A) Polaris, Aldebaran, and Algol.
B) Polaris, Betelgeuse, and Sirius.
C) Betelgeuse, Procyon, and Sirius.
D) Betelgeuse, Rigel, and Aldebaran.
E) Capella, Procyon, and Sirius.
Answer: C
29) The three stars of the Summer Triangle are
A) Antares, Arcturus, and Spica.
B) Arcturus, Vega, and Algol.
C) Deneb, Spica, and Vega.
D) Vega, Deneb, and Altair.
E) Altair, Antares, and Arcturus.
Answer: D
30) Each of the following lists a constellation and a bright star. In all cases but one, the star is
part of the constellation. Which one is the mismatch?
A) Scorpio, Vega
B) Cygnus, Deneb
C) Boötes, Arcturus
D) Virgo, Spica
E) Auriga, Capella
Answer: A
6
Copyright © 2014 Pearson Education, Inc.
31) All of the following are true. Which of the following gives evidence that Earth's orbit is not
perfectly circular?
A) The Sun's angular size changes throughout the year.
B) Earth's seasons are not of exactly equal length.
C) In North America, it is hotter in July than January.
D) Both A and C
E) Both A and B
Answer: E
S1.2 True/False Questions
1) No matter where you live on Earth, except the poles, your meridian extends from due south on
your horizon, through your zenith, to due north on your horizon.
Answer: TRUE
2) Our calendar is based on the length of the tropical year rather than the sidereal year.
Answer: TRUE
3) The coordinates used to locate a position on the celestial sphere are altitude and declination.
Answer: FALSE
4) All directions are south from the North Pole.
Answer: TRUE
5) The summer solstice is east of the vernal equinox by 6 hours of right ascension.
Answer: TRUE
6) The celestial coordinates of the Sun change from day to day.
Answer: TRUE
7) No matter where you live on Earth, the Sun always rises and sets each day.
Answer: FALSE
8) No matter where you live on Earth, the Sun is always directly overhead at noon.
Answer: FALSE
9) On the equator, days and nights are always 12 hours long, no matter what time of year.
Answer: TRUE
10) A year at the south pole consists of 6 months of darkness and 6 months of daylight.
Answer: TRUE
11) The Summer Triangle is formed by the stars Deneb, Vega, and Altair.
Answer: TRUE
12) The Winter Triangle is formed by the stars Betelgeuse, Rigel, and Aldebaran.
Answer: FALSE
7
Copyright © 2014 Pearson Education, Inc.
S1.3 Short Answer Questions
1) Your Local Sky
a. Where is the north (or south) celestial pole in your sky?
b. Describe the meridian in your sky.
c. Describe the celestial equator in your sky.
d. What is the range of declinations that makes a star circumpolar in your sky? Explain.
e. Describe the path of the Sun through your sky on the fall equinox.
f. Describe the path of the Sun through your sky on the winter solstice.
Answer: Answers will vary with latitude; the following is a sample answer for latitude 40°N.
a. The north celestial pole appears in the sky at an altitude of 40°, in the direction due north.
b. The meridian is a half-circle that stretches from the point due south on the horizon, through
the zenith, to the point due north on the horizon.
c. The celestial equator is a half-circle that stretches from the point due east on the horizon,
through an altitude of 50° due south, to the point due west on the horizon.
d. Because the north celestial pole appears due north at an altitude of 40°, a star is circumpolar if
it is within 40° of the north celestial pole. The north celestial pole has a declination of +90°, so
within 40° means declinations greater than +50°.
e. On the fall equinox, the Sun rises due east, reaches an altitude of 50°S on the meridian, and
sets due west.
f. On the winter solstice, the Sun rises more than 23.5° south of due east, reaches an altitude of
50° - 23.5° = 26.5° on the meridian in the south, and sets more than 23.5° south of due west.
2) Suppose you live at the North Pole. Describe the path of the Sun through your sky for each of
the following days:
a. the day of the spring equinox
b. the day of the summer solstice
c. the day of the winter solstice
Answer:
a. On the vernal equinox, the Sun circles the sky on the horizon in 24 hours.
b. On the summer solstice, the Sun circles the sky at a constant altitude of 23.5° in 24 hours.
c. On the winter solstice, the Sun remains well below the horizon all day.
3) Suppose you live at the equator. Describe the path of the Sun through your sky for each of the
following days:
a. the day of the spring equinox
b. the day of the summer solstice
c. the day of the winter solstice
Answer:
a. On the vernal equinox, the Sun rises due east, reaches the zenith at noon, and sets due west.
b. On the summer solstice, the Sun rises exactly 23.5° north of due east, reaches an altitude of
90° - 23.5° = 66.5° on the meridian in the north, and sets exactly 23.5° north of due west.
c. On the winter solstice, the Sun rises exactly 23.5° south of due east, reaches an altitude of 90°
- 23.5° = 66.5° on the meridian in the south, and sets exactly 23.5° south of due west.
8
Copyright © 2014 Pearson Education, Inc.
4) Suppose that you live in Sydney, Australia (latitude 34°S). Describe the path of the Sun
through your sky for each of the following days:
a. the day of the spring equinox
b. the day of the summer solstice
c. the day of the winter solstice
Answer:
a. On the vernal equinox, the Sun rises due east, reaches an altitude of 56°N on the meridian, and
sets due west.
b. On the summer solstice, the Sun rises more than 23.5° north of due east, reaches an altitude of
56° - 23.5° = 32.5° on the meridian in the north, and sets more than 23.5° north of due west.
c. On the winter solstice, the Sun rises more than 23.5° south of due east, reaches an altitude of
56° + 23.5° = 79.5° on the meridian in the north, and sets more than 23.5° south of due west.
5) For vacation, you decide to take a solo boat trip. While contemplating the universe, you lose
track of your location. Fortunately, you have some astronomical tables and instruments, as well
as a UT clock. You thereby put together the following description of your situation:
∙ It is the day of the summer solstice.
∙ The Sun is on your meridian at an altitude of 83.5° in the south.
∙ The UT clock reads 22:00.
a. What is your latitude? How do you know?
b. What is your longitude? How do you know?
Answer:
a. Your latitude is 30°N. Because it is the summer solstice, the Sun follows a path 23.5° north of
the celestial equator through the sky. Thus, the Sun's meridian altitude of 83.5°S tells you that
the celestial equator crosses the meridian at 60°S. Because we know that the celestial equator
crosses the meridian at 90° - (your latitude), your latitude is 90° - 60° = 30°; it is north latitude
because the celestial equator is in your southern sky.
b. Your longitude is 150°W. The Sun is on your meridian, so it is noon for you. The UT clock
reads 22:00, or 10 P.M., so Greenwich is 10 hours ahead of you. Each hour represents 15° of
longitude, so 10 hours means 150°; you are west of Greenwich because your time is behind.
9
Copyright © 2014 Pearson Education, Inc.
6) For vacation, you decide to take a solo boat trip. While contemplating the universe, you lose
track of your location. Fortunately, you have some astronomical tables and instruments, as well
as a UT clock. You thereby put together the following description of your situation:
∙ It is the day of the spring equinox.
∙ The Sun is on your meridian at an altitude of 75° in the south.
∙ The UT clock reads 22:00.
a. What is your latitude? How do you know?
b. What is your longitude? How do you know?
Answer:
a. Your latitude is 15°N. Because it is the vernal equinox, the Sun follows the path of the
celestial equator through the sky. Thus, the Sun's meridian altitude of 75°S tells you that this also
is the altitude at which the celestial equator crosses the meridian. Because we know that the
celestial equator crosses the meridian at 90° - (your latitude), your latitude is 90° - 75° = 15°; it is
north latitude because the celestial equator is in your southern sky.
b. Your longitude is 150°W. The Sun is on your meridian, so it is noon for you. The UT clock
reads 22:00, or 10 P.M.., so Greenwich is 10 hours ahead of you. Each hour represents 15° of
longitude, so 10 hours means 150°; you are west of Greenwich because your time is behind.
7) For vacation, you decide to take a solo boat trip. While contemplating the universe, you lose
track of your location. Fortunately, you have some astronomical tables and instruments, as well
as a UT clock. You thereby put together the following description of your situation:
∙ It is the day of the summer solstice.
∙ The Sun is on your meridian at an altitude of 67.5° in the north.
∙ The UT clock reads 06:00.
a. What is your latitude? How do you know?
b. What is your longitude? How do you know?
Answer:
a. You are on the equator. Because it is the summer solstice, the Sun crosses the meridian 23.5°
north of the celestial equator. Thus the Sun's meridian altitude of 67.5°N tells you that the
celestial equator is passing through your zenith, and hence that you are on the earth's equator.
b. Your longitude is 90°E. The Sun is on your meridian, so it is noon for you. The UT clock
reads 06:00, or 6 A.M., so Greenwich is 6 hours behind you. Each hour represents 15° of
longitude, so 6 hours means 90°; you are east of Greenwich because your time is ahead.
10
Copyright © 2014 Pearson Education, Inc.
8) For vacation, you decide to take a solo boat trip. While contemplating the universe, you lose
track of your location. Fortunately, you have some astronomical tables and instruments, as well
as a UT clock. You thereby put together the following description of your situation:
∙ Your local time is midnight.
∙ Polaris appears at an altitude of 67° in the north.
∙ The UT clock reads 01:00.
a. What is your latitude? How do you know?
b. What is your longitude? How do you know?
Answer:
a. Your latitude is within 1° of 67°N, which you know because that is the altitude of Polaris in
your sky.
b. Your longitude is 15°W. Your local time is midnight and the UT clock reads 01:00, or 1 A.M.,
so Greenwich is 1 hour ahead of you. Thus, you are 15° west of Greenwich.
9) Note to instructors: The following question assumes you gave a "lost at sea" question on your
midterm.
It is often said that history repeats itself. Much to your chagrin, you find that to be the case:
Despite having been rescued during the midterm, you are, once again, lost in a body of water.
Fortunately, you still have your astronomical tables and instruments, as well as a UT clock. You
thereby put together the following description of your situation:
∙ It is the day of the summer solstice.
∙ The Sun is on your meridian at an altitude 73.5° in the south.
∙ The UT clock reads 19:00.
a. What is your latitude? How do you know?
b. What is your longitude? How do you know?
Answer:
a. Your latitude is 40°N, where the Sun crosses the meridian at an altitude of 73.5°S on the
summer solstice.
b. Your longitude is 105°W. The Sun is on your meridian, so it is noon for you. The UT clock
reads 19:00, or 7 P.M., so Greenwich is 7 hours ahead of you. Each hour represents 15° of
longitude, so 7 hours means 105°; you are west of Greenwich because your time is behind. In
fact, it's next year's summer solstice, and you are floating on a small raft in the Boulder
Reservoir. You are lost only because you have become disoriented while contemplating the fourdimensional nature of spacetime and the expansion of the universe.
11
Copyright © 2014 Pearson Education, Inc.
For the following questions, refer to Figure S1.1, which shows a portion of the sky visible in the
early evenings in the fall. Note that five bright stars are labeled with lowercase letters and five
constellations are labeled with capitals. A few hints are also given.
10) Which bright star (lowercase letters) is Capella?
Answer: a
11) Which bright star (lowercase letters) is Aldebaran?
Answer: b
12) Which bright star (lowercase letters) is Algol, the "demon star"?
Answer: c
13) Which constellation (capital letters) is Auriga?
Answer: A
14) Which constellation (capital letters) is Taurus?
Answer: B
15) Which constellation (capital letters) is Perseus?
Answer: C
16) Which constellation (capital letters) is Cassiopeia?
Answer: D
17) Which constellation (capital letters) is Pegasus?
Answer: E
12
Copyright © 2014 Pearson Education, Inc.
For the following questions, refer to Figure S1.2, which shows a portion of the sky visible in the
early evenings in winter. Note that five bright stars are labeled with lowercase letters and five
constellations are labeled with capitals. A few hints are also given.
18) Which bright star (lowercase letters) is Procyon?
Answer: a
19) Which bright star (lowercase letters) is Sirius?
Answer: b
20) Which bright star (lowercase letters) is Betelgeuse?
Answer: c
21) Which bright star (lowercase letters) is Rigel?
Answer: d
22) Which bright star (lowercase letters) is Aldebaran?
Answer: e
23) Which constellation (capital letters) is Canis Minor?
Answer: A
13
Copyright © 2014 Pearson Education, Inc.
For the following questions, refer to Figure S1.2, which shows a portion of the sky visible in the
early evenings in winter. Note that five bright stars are labeled with lowercase letters and five
constellations are labeled with capitals. A few hints are also given.
24) Which constellation (capital letters) is Canis Major?
Answer: B
25) Which constellation (capital letters) is Orion?
Answer: C
26) Which constellation (capital letters) is Gemini?
Answer: D
27) Which constellation (capital letters) is Taurus?
Answer: E
14
Copyright © 2014 Pearson Education, Inc.
Choose the appropriate star from Table S1.1 for the following questions:
Table S1.1
Star
A. Sirius
B. Canopus
C. Alpha
Centauri
D. Arcturus
E. Vega
Right
Ascension
6hr 43m
6hr 23m
Declination
-16°39'
-52°40'
Constellation
Canis Major
Carina
14hr 36m
14hr 13m
18hr 35m
-60°38'
+19°27'
+38°44'
Centaurus
Bootes
Lyra
28) Which star lies closest to the celestial equator on the celestial sphere?
Answer: A
29) Which star lies closest to the north celestial pole on the celestial sphere?
Answer: E
30) Which star lies closest to the south celestial pole on the celestial sphere?
Answer: C
31) Suppose you live at latitude 20°N. Which star passes closest to your zenith on its daily path
through your sky?
Answer: D
32) Suppose you live at latitude 20°S. Which star passes closest to your zenith on its daily path
through your sky?
Answer: A
33) Suppose you live at latitude 30°N. Which star is never visible in your sky?
Answer: C
34) Suppose it is late June. Which star crosses your meridian around midnight? Assume you live
at a latitude where all the stars on this list rise above your horizon each day.
Answer: E
15
Copyright © 2014 Pearson Education, Inc.
Choose the appropriate star from Table S1.2 for the following questions:
Table S1.2
Star
A. Spica
B. Deneb
C. Sirius
D. Alpha
Centauri
E. Vega
RA
13hr 24m .1
20hr 39m .7
6hr 44m .2
Dec.
-11°20'
-45°06'
-16°42'
14hr 38m .4
+60°46'
18hr 35m .2
+38°44'
35) Which star can never be seen at latitude 40°N?
Answer: D
36) Which star appears nearest to the south celestial pole?
Answer: D
37) Which star remains above the horizon for the longest time each day at latitude 40°N?
Answer: B
38) Suppose you are looking at the sky at about midnight on the winter solstice. Which star will
be nearest your meridian? (Hint: Remember that midnight occurs when the Sun is exactly 12
hours away from the meridian.)
Answer: C
39) Which star passes nearest the zenith at latitude 40°N?
Answer: E
40) If both the Sun and a distant star cross your meridian at exactly 12:00 noon today, at what
time will the star cross your meridian tomorrow?
Answer: Tomorrow the star will cross at 11:56 A.M.
41) If the constellation Orion crosses your meridian at midnight in mid-December, at what time
will Orion cross your meridian in mid-January?
Answer: In mid-January it will cross around 10 P.M.
42) Process of Science: Devise an observation involving stars that would provide evidence (not
necessarily proof) that Earth is round. Any observation that can be made from Earth is
acceptable.
Answer: Observe the North Star (or, for that matter, any star) from the North Pole and then
watch its position change as you move towards the equator. Similarly, observe the Sun from
different latitudes.
16
Copyright © 2014 Pearson Education, Inc.
43) Process of Science: Devise an observation to be made from Earth that gives evidence that
our orbit is not perfectly circular.
Answer: Measure the angular size of the Sun and see it grow larger and smaller with the
seasons, indicating that we are moving closer and then farther away. Count the number of days
between equinoxes and solstices, showing that the seasons are not all of equal length. This means
we are speeding up and slowing down, which we know from Kepler's Third Law means that the
orbit isn't perfectly circular.
44) Process of Science: Describe a (rare) observation that directly shows that Venus lies between
the Earth and Sun. What is a simple observation that shows that Mars is further from the Sun
than Earth?
Answer: A Venus transit of the Sun (which only occur about once per century) is a direct and
unambiguous indication that Venus lies between the Sun and Earth. The fact that Mars can
sometimes be seen overhead at midnight means that the Sun and Mars are on different sides of
the Earth, which can only happen if Mars is further from the Sun than Earth.
45) Process of Science: Give some examples of how human exploration of the Earth and our
understanding of the Universe went hand in hand.
Answer: This is an open-ended question, which can include the discovery that the Earth is
round, and the development of scientific tools to measure star positions in order to determine
latitude and, along with accurate clocks, longitude.
S1.4 Mastering Astronomy Reading Quiz
1) Which of the following statements about sidereal and solar days is not true?
A) A sidereal day is the definition of a day on the Earth and a solar day is the definition of a day
on the Sun.
B) A solar day is approximately 4 minutes longer than a sidereal day.
C) A solar day is the amount of time between successive appearances of the Sun on our
meridian.
D) A sidereal day is the amount of time between successive appearances of any star on our
meridian.
Answer: A
2) What is the difference between a synodic month and a sidereal month?
A) A synodic month is our 30 or 31 day calendar month and a sidereal month is the time it takes
for a cycle of the Moon's phases.
B) A synodic month is the time it takes for a cycle of lunar phases and a sidereal month is the
time it takes the Moon to orbit Earth (relative to the stars).
C) A synodic month is the time it takes for a cycle of the Moon's phases and a sidereal month is
our 30 or 31 day calendar month.
D) A synodic month is based on the orbit of some planet around the Sun and a sidereal month is
based on the orbit of the Moon around Earth.
Answer: B
17
Copyright © 2014 Pearson Education, Inc.
3) When we say that Jupiter is at opposition we mean that it
A) is behind the Sun as seen from Earth, so that it appears very close to the Sun in our sky.
B) is at its greatest western elongation.
C) it is at the point in its orbit where it is farthest from the Sun.
D) appears on the opposite side of the sky from the Sun, so that it is on our meridian at midnight.
Answer: D
4) What kind of time can be read directly from a sundial?
A) apparent solar time
B) mean solar time
C) standard time
D) universal time
Answer: A
5) Universal time, or UT, is
A) another name for standard time.
B) the mean solar time in Greenwich, England.
C) the apparent solar time in Greenwich, England.
D) a timekeeping system based on careful observations of positions of stars throughout the
universe.
Answer: B
6) Our modern calendar is also known as
A) the Gregorian calendar.
B) the Julian calendar.
C) the Metonic calendar.
D) the Universal Calendar (UC).
Answer: A
7) Which of the following best describes the meaning of declination and right ascension?
A) They are coordinates on the celestial sphere that are very similar to the coordinates of altitude
and direction on Earth.
B) They are used to describe the locations and distances of stars that we see in the night sky.
C) They are coordinates on the celestial sphere, with declination telling us the angular distance of
an object from the celestial equator and right ascension telling us how far around the celestial
sphere an object is located from the vernal equinox.
D) They are terms used by astronomers to describe how the sky changes with the seasons.
Answer: C
8) The Sun's declination on June 21st is
A) +23.5 degrees.
B) 0 degrees.
C) -23.5 degrees.
D) different depending on where you are on Earth.
Answer: A
18
Copyright © 2014 Pearson Education, Inc.
9) Which of the following best describes the Tropic of Cancer?
A) It is the circle of latitude on Earth for which the Sun appears to remain above the horizon for
a full 24 hours on the summer solstice.
B) It is the circle of latitude on Earth for which the Sun appears directly overhead at noon on the
spring and fall equinoxes.
C) It is the line of right ascension passing through the constellation of Cancer.
D) It is the circle of latitude on Earth for which the Sun appears directly overhead at noon on the
summer solstice.
Answer: D
10) Suppose you live at latitude 40°N. Which of the following describes the path of the celestial
equator through your sky?
A) It extends from due east on your horizon, to an altitude of 50° in the south, to due west on
your horizon.
B) It extends from due south on your horizon, to your zenith, to due north on your horizon.
C) It extends from due east on your horizon, to an altitude of 40° in the south, to due west on
your horizon.
D) It extends from due east on your horizon, to an altitude of 40° in the north, to due west on
your horizon.
Answer: A
11) Suppose it is January and the Sun remains above your horizon all day long. Where must you
be located?
A) at the South Pole
B) at the North Pole
C) somewhere between the Antarctic Circle and the South Pole
D) somewhere between the Arctic Circle and the North Pole
Answer: C
12) From a latitude of 60 degrees north during the winter, the Sun will
A) spend most of each day below the horizon.
B) spend most of each day above the horizon.
C) never be seen above the horizon.
D) end a few weeks continuously below the horizon.
Answer: A
13) If you were standing on Earth's equator, where would you look to see the north celestial
pole?
A) directly overhead
B) on your horizon due north
C) toward the ecliptic
D) due east
Answer: B
19
Copyright © 2014 Pearson Education, Inc.
14) Suppose you know the declination of a bright star that is now crossing your meridian. What
else must you measure in order to determine your latitude?
A) the star's altitude
B) the apparent solar time
C) the current universal time
D) the star's right ascension
Answer: A
15) What is the global positioning system (GPS)?
A) a system for determining positions on the Earth by careful observations of the Sun and stars
B) a system of determining positions on the Earth by receiving radio signals from many groundbased beacons
C) a system for determining positions on Earth using signals from a set of satellites in Earth orbit
D) a term used to refer to any type of celestial navigation
Answer: C
S1.5 Mastering Astronomy Concept Quiz
1) Which of the following best explains why a solar day is longer than a sidereal day?
A) Because Earth orbits the Sun at the same time it rotates, Earth must make slightly more than
one full rotation between noon one day and noon the next.
B) The precession of Earth's axis gradually changes the length of the solar day while leaving the
length of the sidereal day alone.
C) The fact that Earth's orbit is not a perfect circle causes the length of the solar day to vary
during the year, so that it the solar day is sometimes longer and sometimes shorter than a sidereal
day.
D) The Sun rotates much as the Earth does, but more slowly, so that a solar day is longer than a
sidereal day.
Answer: A
2) When should we next expect to observe a transit of the Sun by Mars?
A) 2010
B) 2015
C) 2140
D) Never
Answer: D
3) A friend says she saw a planet shining on her meridian at midnight. Which planet can you be
sure that she did not see?
A) Venus
B) Mars
C) Jupiter
D) Saturn
Answer: A
20
Copyright © 2014 Pearson Education, Inc.
4) Suppose you have a time-keeping device that always reads precisely 12:00 when the Sun
crosses your meridian. What kind of time is this clock keeping?
A) mean solar time
B) standard time
C) apparent solar time
D) universal time
Answer: C
5) All the following statements are true. Which one explains why mean solar time differs from
apparent solar time?
A) The length of a solar day is not always exactly 24 hours.
B) Earth's rotation period is actually about 23 hours and 56 minutes, not 24 hours.
C) Earth's axis precesses with a period of about 26,000 years.
D) The Sun reaches the meridian at different times at different longitudes within the same time
zone.
Answer: A
6) As viewed from any place within the continental United States, noon on apparent solar time is
defined as the moment when the Sun is
A) directly overhead.
B) ante meridiem.
C) at a right ascension of 0 hours.
D) directly south.
Answer: D
7) All the following statements are true. Which one explains why our calendar has leap years?
A) Earth's axis precesses with a period of about 26,000 years.
B) There is a difference between a sidereal year and a tropical year.
C) A tropical year is slightly more than 365 days.
D) Earth's speed varies as it orbits the Sun.
Answer: C
Consider the following data for four stars:
Star
Spica
Deneb
Sirius
Alpha Centauri
RA
hr
13 24m.1
20hr39m.7
6hr44m.2
14hr38m.4
Dec.
+
-
8) Which of these stars lies closest to the north celestial pole on the celestial sphere?
A) Deneb
B) Alpha Centauri
C) Spica
D) Sirius
Answer: A
21
Copyright © 2014 Pearson Education, Inc.
9) Suppose you live at latitude 30°S. Which star is circumpolar in your sky?
A) Alpha Centauri
B) Deneb
C) Spica
D) Sirius
Answer: A
10) Suppose that you are looking at the sky at about midnight on the winter solstice. Which star
will be nearest to your meridian?
A) Alpha Centauri
B) Sirius
C) Spica
D) Deneb
Answer: B
11) Which of the following statements is not true about the sky at Earth's equator?
A) Over the course of the year, all 88 constellations will at some point be visible in the evening
sky.
B) There are no circumpolar stars in the equatorial sky.
C) The Sun will pass directly overhead around noon each day.
D) The north celestial pole is directly on your horizon, due north (with Polaris quite nearby).
Answer: C
12) Suppose Earth's axis had a greater tilt (more than 23.5 degrees). Which of the following
statements would not be true?
A) The celestial sphere would be covered by a different set of constellations than it is with the
current axis tilt.
B) Seasonal temperature variations would be more extreme than they are with the current tilt.
C) We would have more daylight in summer and less daylight in winter than we do with the
current tilt.
D) The Arctic and Antarctic circles would be located closer to the equator than they are now.
Answer: A
13) Which of the following explains why navigators prior to a few hundred years ago found it
much more difficult to determine longitude than latitude?
A) Determining longitude requires mathematical techniques that were not known at the time.
B) Determining longitude requires much more precise measurements of angles in the sky than
does latitude.
C) Determining longitude requires accurate tables of the celestial coordinates of stars, while
determining latitude does not.
D) Determining longitude requires an accurate clock, but latitude does not.
Answer: D
22
Copyright © 2014 Pearson Education, Inc.
14) It's the summer solstice, the Sun is at your zenith, and you have a UT clock that tells you it is
midnight in Greenwich, England. Where are you?
A) on the Tropic of Cancer near the International Date Line
B) on the equator near the International Date Line
C) on the Tropic of Cancer, due south of Greenwich, England
D) at latitude 25°S and longitude 49°E
Answer: A
15) The north celestial pole appears 30° above your horizon. The star Vega is on your meridian.
By studying your star charts and your clocks, you determine that Vega crossed the meridian in
Greenwich (England) 3 hours ago. Where are you?
A) latitude 30°N, longitude 45° west
B) latitude 30°N, longitude 3° west
C) latitude 60°N, longitude 45° west
D) It is not possible to determine your longitude from the information given.
Answer: A
23
Copyright © 2014 Pearson Education, Inc.