Question 1

On December 21 of this year, the Sun will be at what declination angle?

Accepted Answer

A)  90° 
B)  +23.5° 
C)  0° 
D)  -23.5° 
A)  90° 
B)  +23.5° 
C)  0° 
D)  -23.5° D

Question 2

During a total lunar eclipse, the Moon is

Accepted Answer

A)  totally invisible since Earth blocks all light from reaching it. 
B)  barely visible because of "zodiacal light," that is, sunlight reflected off dust grains in space. 
C)  barely visible because it glows slightly by its own light. 
D)  barely visible because of light passing through Earth's atmosphere. 
A)  totally invisible since Earth blocks all light from reaching it. 
B)  barely visible because of "zodiacal light," that is, sunlight reflected off dust grains in space. 
C)  barely visible because it glows slightly by its own light. 
D)  barely visible because of light passing through Earth's atmosphere. D

Question 3

Astronauts on the Moon look back at Earth, a distance of about 400,000 km. If the cities of Washington, D.C., and New York are separated by about 300 km, what will the angle between them be when viewed from the Moon?

Accepted Answer

A)  1.3° 
B)  1300° 
C)  2.5° 
D)  2.5 arcminutes 
A)  1.3° 
B)  1300° 
C)  2.5° 
D)  2.5 arcminutes D

Question 4

Why are different phases of the Moon observable from Earth?

Accepted Answer

A)  The motion of the Moon in its orbit around Earth causes observers to see different amounts of Earth's shadow falling on the Moon. 
B)  The motion of the Moon in its orbit around Earth causes observers to see different amounts of the sunlit side of the Moon. 
C)  The distance of the Moon from Earth changes because of the elliptical orbit of the Moon, causing the sunlit side of the Moon to move relative to Earth. 
D)  The rotation of the Moon around its own axis causes observers to see different amounts of the sunlit side of the Moon. 
A)  The motion of the Moon in its orbit around Earth causes observers to see different amounts of Earth's shadow falling on the Moon. 
B)  The motion of the Moon in its orbit around Earth causes observers to see different amounts of the sunlit side of the Moon. 
C)  The distance of the Moon from Earth changes because of the elliptical orbit of the Moon, causing the sunlit side of the Moon to move relative to Earth. 
D)  The rotation of the Moon around its own axis causes observers to see different amounts of the sunlit side of the Moon.

Question 5

The angle subtended at an observer by a city transit bus (length 9 m) at a distance of 1000 m is close to

Accepted Answer

A)  1000/9, or 111.1 arcseconds. 
B)  ½ of a degree. 
C)  9000 arcminutes. 
D)  9/1000, or 0.009 arcseconds. 
A)  1000/9, or 111.1 arcseconds. 
B)  ½ of a degree. 
C)  9000 arcminutes. 
D)  9/1000, or 0.009 arcseconds.

Question 6

What was the approximate value of right ascension of the Sun this year on December 21?

Accepted Answer

A)  6 hours 0 minutes 
B)  0 hours 0 minutes 
C)  18 hours 0 minutes 
D)  12 hours 0 minutes 
A)  6 hours 0 minutes 
B)  0 hours 0 minutes 
C)  18 hours 0 minutes 
D)  12 hours 0 minutes

Question 7

How long will it take for precession to move Earth's spin axis to a position perpendicular to the ecliptic plane?

Accepted Answer

A)  no time at all because the axis is in this position now 
B)  a very long or even infinite time because it is very unlikely to happen 
C)  13,000 years 
D)  26,000 years 
A)  no time at all because the axis is in this position now 
B)  a very long or even infinite time because it is very unlikely to happen 
C)  13,000 years 
D)  26,000 years

Question 8

Would a calendar based on a sidereal day be satisfactory?

Accepted Answer

A)  No. Noon on the clock would become earlier than the high point of the Sun by 4 minutes each day until eventually it would occur in the middle of the night. 
B)  No. Noon on the clock would become later than the high point of the Sun by 4 minutes each day until eventually it would occur in the middle of the night. 
C)  No. The seasons would be reversed. 
D)  Yes, but, we would have to add an extra day every year. 
A)  No. Noon on the clock would become earlier than the high point of the Sun by 4 minutes each day until eventually it would occur in the middle of the night. 
B)  No. Noon on the clock would become later than the high point of the Sun by 4 minutes each day until eventually it would occur in the middle of the night. 
C)  No. The seasons would be reversed. 
D)  Yes, but, we would have to add an extra day every year.

Question 9

Solar eclipses (when the Moon and Sun are precisely in line) can be either total (Sun completely covered) or annular (Sun not quite covered) when viewed from the eclipse centerline. This is because

Accepted Answer

A)  the Moon has deep valleys on its surface. 
B)  the Moon's orbit is inclined at several degrees to that of Earth. 
C)  the Moon's distance from Earth varies from eclipse to eclipse. 
D)  of the time of day at the viewing site; annular eclipses always occur in early mornings and early evenings. 
A)  the Moon has deep valleys on its surface. 
B)  the Moon's orbit is inclined at several degrees to that of Earth. 
C)  the Moon's distance from Earth varies from eclipse to eclipse. 
D)  of the time of day at the viewing site; annular eclipses always occur in early mornings and early evenings.

Question 10

Which one of these is NOT a zodiac constellation?

Accepted Answer

A)  Pisces 
B)  Cancer 
C)  Ophiuchus 
D)  Cygnus 
A)  Pisces 
B)  Cancer 
C)  Ophiuchus 
D)  Cygnus

Question 11

A science fiction writer, writing a story about inhabitants on Earth in 14,000 A.D. who have survived a disaster that included the loss of modern navigational aids, describes them traveling due north across barren wastes by walking toward Polaris, the pole star. What is wrong with this situation?

Accepted Answer

A)  Polaris will have moved away from due north since it is moving rapidly with respect to surrounding stars. 
B)  Polaris will no longer be due north because of Earth's precession. 
C)  By that time, Polaris will be due south, not due north, because of the reversal of Earth's spin axis. 
D)  Polaris will no longer be visible since its lifetime is only a few thousand years. 
A)  Polaris will have moved away from due north since it is moving rapidly with respect to surrounding stars. 
B)  Polaris will no longer be due north because of Earth's precession. 
C)  By that time, Polaris will be due south, not due north, because of the reversal of Earth's spin axis. 
D)  Polaris will no longer be visible since its lifetime is only a few thousand years.

Question 12

What will be the elevation angle of the Sun above the horizon at midday on June 21 every year at latitude 66.5° S?

Accepted Answer

A)  90°, in the zenith 
B)  23.5° 
C)  The Sun will not appear above the horizon at all on this date at this location. 
D)  0° 
A)  90°, in the zenith 
B)  23.5° 
C)  The Sun will not appear above the horizon at all on this date at this location. 
D)  0°

Question 13

Over an interval of 6 months, the tilt of Earth's spin axis with respect to the background stars will change by

Accepted Answer

A)  0°. 
B)  23.5°. 
C)  47°. 
D)  180°. 
A)  0°. 
B)  23.5°. 
C)  47°. 
D)  180°.

Question 14

If the plane of the Moon's orbit were the same as the ecliptic plane, there would be a lunar eclipse

Accepted Answer

A)  twice per month. 
B)  twice per year. 
C)  every day. 
D)  once per month. 
A)  twice per month. 
B)  twice per year. 
C)  every day. 
D)  once per month.

Question 15

The phase of the Moon when Sun and Moon are separated by 6 hours of right ascension is always

Accepted Answer

A)  full Moon. 
B)  new Moon. 
C)  crescent. 
D)  either first or third quarter. 
A)  full Moon. 
B)  new Moon. 
C)  crescent. 
D)  either first or third quarter.

Question 16

If the stars Polaris and Arcturus are seen to be 71° apart, as shown in Figure 1-5, how far away from Polaris is the closest star in Ursa Major?

Accepted Answer

A)  0.25° 
B)  2.5° 
C)  25° 
D)  250° 
A)  0.25° 
B)  2.5° 
C)  25° 
D)  250°

Question 17

The motion of the Moon across the sky in 1 hour, as seen against the background of stars, is approximately

Accepted Answer

A)  its own diameter (1/2°). 
B)  1/10°. 
C)  4°. 
D)  13°. 
A)  its own diameter (1/2°). 
B)  1/10°. 
C)  4°. 
D)  13°.

Question 18

The true orbital period of Earth around the Sun, defined as the time taken to complete one orbit with respect to the background stars, is 1

Accepted Answer

A)  sidereal year. 
B)  Gregorian year. 
C)  tropical year. 
D)  solar day. 
A)  sidereal year. 
B)  Gregorian year. 
C)  tropical year. 
D)  solar day.

Question 19

Which way does an observer move with respect to the stars because of the rotation of Earth?

Accepted Answer

A)  westward 
B)  southward 
C)  northward 
D)  eastward 
A)  westward 
B)  southward 
C)  northward 
D)  eastward

Question 20

One-billionth divided by one-millionth is equal to

Accepted Answer

A)  10-15 
B)  1015 
C)  10-3 
D)  103 
A)  10-15 
B)  1015 
C)  10-3 
D)  103

On December 21 of this year, the Sun will be at what declination angle?

During a total lunar eclipse, the Moon is

Astronauts on the Moon look back at Earth, a distance of about 400,000 km. If the cities of Washington, D.C., and New York are separated by about 300 km, what will the angle between them be when viewed from the Moon?

Why are different phases of the Moon observable from Earth?

The angle subtended at an observer by a city transit bus (length 9 m) at a distance of 1000 m is close to

What was the approximate value of right ascension of the Sun this year on December 21?

How long will it take for precession to move Earth's spin axis to a position perpendicular to the ecliptic plane?

Would a calendar based on a sidereal day be satisfactory?

Solar eclipses (when the Moon and Sun are precisely in line) can be either total (Sun completely covered) or annular (Sun not quite covered) when viewed from the eclipse centerline. This is because

Which one of these is NOT a zodiac constellation?

A science fiction writer, writing a story about inhabitants on Earth in 14,000 A.D. who have survived a disaster that included the loss of modern navigational aids, describes them traveling due north across barren wastes by walking toward Polaris, the pole star. What is wrong with this situation?

What will be the elevation angle of the Sun above the horizon at midday on June 21 every year at latitude 66.5° S?

Over an interval of 6 months, the tilt of Earth's spin axis with respect to the background stars will change by

If the plane of the Moon's orbit were the same as the ecliptic plane, there would be a lunar eclipse

The phase of the Moon when Sun and Moon are separated by 6 hours of right ascension is always

If the stars Polaris and Arcturus are seen to be 71° apart, as shown in Figure 1-5, how far away from Polaris is the closest star in Ursa Major?

The motion of the Moon across the sky in 1 hour, as seen against the background of stars, is approximately

The true orbital period of Earth around the Sun, defined as the time taken to complete one orbit with respect to the background stars, is 1

Which way does an observer move with respect to the stars because of the rotation of Earth?

One-billionth divided by one-millionth is equal to

Gravitation and the Motion of the Planets

Light and Telescopes

Atomic Physics and Spectra

Exoplanets and the Formation of Planetary Systems

Formation of the Solar System

Earth and the Moon

The Other Terrestrial Planets

The Outer Planets

Vagabonds of the Solar System

The Sun: Our Extraordinary Star

Characterizing Stars

The Lives of Stars From Birth Through Middle Age

The Death of Stars

Black Holes: Matters of Gravity

The Milky Way Galaxy

Galaxies

Quasars and Other Active Galaxies

Cosmology

Astrobiology

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Exam 1: Discovering the Night Sky

On December 21 of this year, the Sun will be at what declination angle?

During a total lunar eclipse, the Moon is

Astronauts on the Moon look back at Earth, a distance of about 400,000 km. If the cities of Washington, D.C., and New York are separated by about 300 km, what will the angle between them be when viewed from the Moon?

Why are different phases of the Moon observable from Earth?

The angle subtended at an observer by a city transit bus (length 9 m) at a distance of 1000 m is close to

What was the approximate value of right ascension of the Sun this year on December 21?

How long will it take for precession to move Earth's spin axis to a position perpendicular to the ecliptic plane?

Would a calendar based on a sidereal day be satisfactory?

Solar eclipses (when the Moon and Sun are precisely in line) can be either total (Sun completely covered) or annular (Sun not quite covered) when viewed from the eclipse centerline. This is because

Which one of these is NOT a zodiac constellation?

A science fiction writer, writing a story about inhabitants on Earth in 14,000 A.D. who have survived a disaster that included the loss of modern navigational aids, describes them traveling due north across barren wastes by walking toward Polaris, the pole star. What is wrong with this situation?

What will be the elevation angle of the Sun above the horizon at midday on June 21 every year at latitude 66.5° S?

Over an interval of 6 months, the tilt of Earth's spin axis with respect to the background stars will change by

If the plane of the Moon's orbit were the same as the ecliptic plane, there would be a lunar eclipse

The phase of the Moon when Sun and Moon are separated by 6 hours of right ascension is always

If the stars Polaris and Arcturus are seen to be 71° apart, as shown in Figure 1-5, how far away from Polaris is the closest star in Ursa Major?

The motion of the Moon across the sky in 1 hour, as seen against the background of stars, is approximately

The true orbital period of Earth around the Sun, defined as the time taken to complete one orbit with respect to the background stars, is 1

Which way does an observer move with respect to the stars because of the rotation of Earth?

One-billionth divided by one-millionth is equal to

Gravitation and the Motion of the Planets

Light and Telescopes

Atomic Physics and Spectra

Exoplanets and the Formation of Planetary Systems

Formation of the Solar System

Earth and the Moon

The Other Terrestrial Planets

The Outer Planets

Vagabonds of the Solar System

The Sun: Our Extraordinary Star

Characterizing Stars

The Lives of Stars From Birth Through Middle Age

The Death of Stars

Black Holes: Matters of Gravity

The Milky Way Galaxy

Galaxies

Quasars and Other Active Galaxies

Cosmology

Astrobiology

Filters